Science.gov

Sample records for area plastic scintillator

  1. Advanced Large Area Plastic Scintillator Project (ALPS): Final Report

    SciTech Connect

    Jordan, David V.; Reeder, Paul L.; Todd, Lindsay C.; Warren, Glen A.; McCormick, Kathleen R.; Stephens, Daniel L.; Geelhood, Bruce D.; Alzheimer, James M.; Crowell, Shannon L.; Sliger, William A.

    2008-02-05

    The advanced Large-Area Plastic Scintillator (ALPS) Project at Pacific Northwest National Laboratory investigated possible technological avenues for substantially advancing the state-of-the-art in gamma-ray detection via large-area plastic scintillators. The three predominant themes of these investigations comprised the following: * Maximizing light collection efficiency from a single large-area sheet of plastic scintillator, and optimizing hardware event trigger definition to retain detection efficiency while exploiting the power of coincidence to suppress single-PMT "dark current" background; * Utilizing anti-Compton vetoing and supplementary spectral information from a co-located secondary, or "Back" detector, to both (1) minimize Compton background in the low-energy portion of the "Front" scintillator's pulse-height spectrum, and (2) sharpen the statistical accuracy of the front detector's low-energy response prediction as impelmented in suitable energy-windowing algorithms; and * Investigating alternative materials to enhance the intrinsic gamma-ray detection efficiency of plastic-based sensors.

  2. Plastic scintillation dosimetry: Optimal selection of scintillating fibers and scintillators

    SciTech Connect

    Archambault, Louis; Arsenault, Jean; Gingras, Luc; Sam Beddar, A.; Roy, Rene; Beaulieu, Luc

    2005-07-15

    Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter.

  3. Plastic scintillation dosimetry: optimal selection of scintillating fibers and scintillators.

    PubMed

    Archambault, Louis; Arsenault, Jean; Gingras, Luc; Beddar, A Sam; Roy, René; Beaulieu, Luc

    2005-07-01

    Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter.

  4. Extruding plastic scintillator at Fermilab

    SciTech Connect

    Anna Pla-Dalmau; Alan D. Bross; Victor V. Rykalin

    2003-10-31

    An understanding of the costs involved in the production of plastic scintillators and the development of a less expensive material have become necessary with the prospects of building very large plastic scintillation detectors. Several factors contribute to the high cost of plastic scintillating sheets, but the principal reason is the labor-intensive nature of the manufacturing process. In order to significantly lower the costs, the current casting procedures had to be abandoned. Since polystyrene is widely used in the consumer industry, the logical path was to investigate the extrusion of commercial-grade polystyrene pellets with dopants to yield high quality plastic scintillator. This concept was tested and high quality extruded plastic scintillator was produced. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. An extrusion line has recently been installed at Fermilab in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new facility will serve to further develop and improve extruded plastic scintillator. This paper will discuss the characteristics of extruded plastic scintillator and its raw materials, the different manufacturing techniques and the current R&D program at Fermilab.

  5. Extruded plastic scintillator including inorganic powders

    DOEpatents

    Bross, Alan D.; Mellott, Kerry L.; Pla-Dalmau, Anna

    2006-06-27

    A method for producing a plastic scintillator is disclosed. A plurality of nano-sized particles and one or more dopants can be combined with a plastic material for the formation of a plastic scintillator thereof. The nano-sized particles, the dopant and the plastic material can be combined within the dry inert atmosphere of an extruder to produce a reaction that results in the formation of a plastic scintillator thereof and the deposition of energy within the plastic scintillator, such that the plastic scintillator produces light signifying the detection of a radiative element. The nano-sized particles can be treated with an inert gas prior to processing the nano-sized particles, the dopant and the plastic material utilizing the extruder. The plastic scintillator can be a neutron-sensitive scintillator, x-ray sensitive scintillator and/or a scintillator for the detection of minimum ionizing particles.

  6. Extruded plastic scintillator for MINERvA

    SciTech Connect

    Pla-Dalmau, Anna; Bross, Alan D.; Rykalin, Victor V.; Wood, Brian M.; /NICADD, DeKalb

    2005-11-01

    An extrusion line has recently been installed at Fermilab in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new facility will serve to further develop and improve extruded plastic scintillator. Since polystyrene is widely used in the consumer industry, the logical path was to investigate the extrusion of commercial-grade polystyrene pellets with dopants to yield high quality plastic scintillator. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. A new experiment at Fermilab is pursuing the use of extruded plastic scintillator. A new plastic scintillator strip is being tested and its properties characterized. The initial results are presented here.

  7. Epoxy resins produce improved plastic scintillators

    NASA Technical Reports Server (NTRS)

    Markley, F. W.

    1967-01-01

    Plastic scintillator produced by the substitution of epoxy resins for the commonly used polystyrene is easy to cast, stable at room temperature, and has the desirable properties of a thermoset or cross-linked system. Such scintillators can be immersed directly in strong solvents, an advantage in many chemical and biological experiments.

  8. Current status on plastic scintillators modifications.

    PubMed

    Bertrand, Guillaume H V; Hamel, Matthieu; Sguerra, Fabien

    2014-11-24

    Recent developments of plastic scintillators are reviewed, from 2000 to March 2014, distributed in two different chapters. First chapter deals with the chemical modifications of the polymer backbone, whereas modifications of the fluorescent probe are presented in the second chapter. All examples are provided with the scope of detection of various radiation particles. The main characteristics of these newly created scintillators and their detection properties are given. PMID:25335882

  9. Temperature dependence of BCF plastic scintillation detectors

    PubMed Central

    Wootton, Landon; Beddar, Sam

    2013-01-01

    We examined temperature dependence in plastic scintillation detectors (PSDs) made of BCF-60 or BCF-12 scintillating fiber coupled to optical fiber with cyanoacrylate. PSDs were subjected to a range of temperatures using a temperature-controlled water bath and irradiated at each temperature while either the dose was measured using a CCD camera or the spectral output was measured using a spectrometer. The spectrometer was used to examine the intensity and spectral distribution of scintillation light emitted by the PSDs, Cerenkov light generated within the PSD, and light transmitted through an isolated optical coupling. BCF-60 PSDs exhibited a 0.50% decrease and BCF-12 PSDs a 0.09% decrease in measured dose per °C increase, relative to dose measured at 22°C. Spectrometry revealed that the total intensity of the light generated by BCF-60 and BCF-12 PSDs decreased by 0.32% and 0.13%, respectively, per °C increase. The spectral distribution of the light changed slightly with temperature for both PSDs, accounting for the disparity between the change in measured dose and total light output. The generation of Cerenkov light was temperature independent. However, light transmitted through optical coupling between the scintillator and the optical fiber also exhibited temperature dependence. PMID:23574889

  10. Plastic fiber scintillator response to fast neutrons

    SciTech Connect

    Danly, C. R.; Sjue, S.; Wilde, C. H.; Merrill, F. E.; Haight, R. C.

    2014-11-15

    The Neutron Imaging System at NIF uses an array of plastic scintillator fibers in conjunction with a time-gated imaging system to form an image of the neutron emission from the imploded capsule. By gating on neutrons that have scattered from the 14.1 MeV DT energy to lower energy ranges, an image of the dense, cold fuel around the hotspot is also obtained. An unmoderated spallation neutron beamline at the Weapons Neutron Research facility at Los Alamos was used in conjunction with a time-gated imaging system to measure the yield of a scintillating fiber array over several energy bands ranging from 1 to 15 MeV. The results and comparison to simulation are presented.

  11. Methods for the continuous production of plastic scintillator materials

    DOEpatents

    Bross, Alan; Pla-Dalmau, Anna; Mellott, Kerry

    1999-10-19

    Methods for producing plastic scintillating material employing either two major steps (tumble-mix) or a single major step (inline-coloring or inline-doping). Using the two step method, the polymer pellets are mixed with silicone oil, and the mixture is then tumble mixed with the dopants necessary to yield the proper response from the scintillator material. The mixture is then placed in a compounder and compounded in an inert gas atmosphere. The resultant scintillator material is then extruded and pelletized or formed. When only a single step is employed, the polymer pellets and dopants are metered into an inline-coloring extruding system. The mixture is then processed under a inert gas atmosphere, usually argon or nitrogen, to form plastic scintillator material in the form of either scintillator pellets, for subsequent processing, or as material in the direct formation of the final scintillator shape or form.

  12. Calibration of Small Plastic Scintillators for Imaging Applications

    SciTech Connect

    Pozzi, S.

    2005-01-19

    This report presents the results of measurements and simulations performed with 12 small plastic scintillation detectors manufactured by Scionix for imaging applications. The scintillator is equivalent to a Bicron BC-420 plastic scintillator. A gamma calibration is presented to determine the voltage to be applied on each detector to ensure uniform detector operation. Time of flight measurements performed with a Cf-252 source are also presented. Comparisons between experimental data and data from the Monte Carlo simulations show good agreement for time lags of 0 to 70 ns.

  13. Transparent plastic scintillators for neutron detection based on lithium salicylate

    NASA Astrophysics Data System (ADS)

    Mabe, Andrew N.; Glenn, Andrew M.; Carman, M. Leslie; Zaitseva, Natalia P.; Payne, Stephen A.

    2016-01-01

    Transparent plastic scintillators with pulse shape discrimination containing 6Li salicylate have been synthesized by bulk polymerization with a maximum 6Li loading of 0.40 wt%. Photoluminescence and scintillation responses to gamma-rays and neutrons are reported herein. Plastics containing 6Li salicylate exhibit higher light yields and permit a higher loading of 6Li as compared to previously reported plastics based on lithium 3-phenylsalicylate. However, pulse shape discrimination performance is reduced in lithium salicylate plastics due to the requirement of adding more nonaromatic monomers to the polymer matrix as compared to those based on lithium 3-phenylsalicylate. Reduction in light yield and pulse shape discrimination performance in lithium-loaded plastics as compared to pulse shape discrimination plastics without lithium is interpreted in terms of energy transfer interference by the aromatic lithium salts.

  14. Final LDRD report : advanced plastic scintillators for neutron detection.

    SciTech Connect

    Vance, Andrew L.; Mascarenhas, Nicholas; O'Bryan, Greg; Mrowka, Stanley

    2010-09-01

    This report summarizes the results of a one-year, feasibility-scale LDRD project that was conducted with the goal of developing new plastic scintillators capable of pulse shape discrimination (PSD) for neutron detection. Copolymers composed of matrix materials such as poly(methyl methacrylate) (PMMA) and blocks containing trans-stilbene (tSB) as the scintillator component were prepared and tested for gamma/neutron response. Block copolymer synthesis utilizing tSBMA proved unsuccessful so random copolymers containing up to 30% tSB were prepared. These copolymers were found to function as scintillators upon exposure to gamma radiation; however, they did not exhibit PSD when exposed to a neutron source. This project, while falling short of its ultimate goal, demonstrated the possible utility of single-component, undoped plastics as scintillators for applications that do not require PSD.

  15. Characterizing Properties and Performance of 3D Printed Plastic Scintillators

    NASA Astrophysics Data System (ADS)

    McCormick, Jacob

    2015-10-01

    We are determining various characteristics of the performance of 3D printed scintillators. A scintillator luminesces when an energetic particle raises electrons to an excited state by depositing some of its energy in the atom. When these excited electrons fall back down to their stable states, they emit the excess energy as light. We have characterized the transmission spectrum, emission spectrum, and relative intensity of light produced by 3D printed scintillators. We are also determining mechanical properties such as tensile strength and compressibility, and the refractive index. The emission and transmission spectra were measured using a monochromator. By observing the transmission spectrum, we can see which optical wavelengths are absorbed by the scintillator. This is then used to correct the emission spectrum, since this absorption is present in the emission spectrum. Using photomultiplier tubes in conjunction with integration hardware (QDC) to measure the intensity of light emitted by 3D printed scintillators, we compare with commercial plastic scintillators. We are using the characterizations to determine if 3D printed scintillators are a viable alternative to commercial scintillators for use at Jefferson Lab in nuclear and accelerated physics detectors. I would like to thank Wouter Deconinck, as well as the Parity group at the College of William and Mary for all advice and assistance with my research.

  16. The response of scintillators to heavy ions: 1, Plastics

    SciTech Connect

    McMahan, M.A.

    1987-10-01

    The response of various scintillator detectors to ions of A = 1-84 and energies E/A = 5 to 30 MeV have been measured, and are found to be linear above an energy of 100 MeV. Results are presented for a typical organic plastic scintillator including parametrizations of the data as a function of Z, A, and energy. These results can be used by anyone using scintillators as heavy ion detectors, with one calibration point giving a normalization that allows use of the whole set of curves. The response functions are compared to previous parametrizations at lower energies and discussed in terms of the theory of delta-ray formation in the scintillator.

  17. Radiation damage by neutrons to plastic scintillators

    SciTech Connect

    Buss, G.; Dannemann, A.; Holm, U.; Wick, K.

    1995-08-01

    Polystyrene based scintillator SCSN38, wavelength shifter Y7 with polymethylmethacrylate matrix and pure PM-MA light guide GS218 have been irradiated in the mixed radiation field of a pool reactor. About 77% of the dose released in SCSN38 was caused by the {gamma}-field, 23% by fast neutrons. The total dose ranged from 2 to 105 kGy. The dose measurements were made using alanine dosimeters. Transmission and fluorescence of the samples have been measured before and several times after irradiation. The radiation damage results shown o differences to irradiations in pure {gamma}-fields with corresponding released doses.

  18. Preparation and characterization of a novel UV-curable plastic scintillator

    NASA Astrophysics Data System (ADS)

    Zhu, Jun; Ding, Yunyu; Zhu, Jiayi; Qi, Di; Su, Ming; Xu, Yewei; Bi, Yutie; Lin, Runxiong; Zhang, Lin

    2016-05-01

    A novel UV-curable plastic scintillator was first prepared by using the technology of photosensitivity rapid prototyping. It used the copolymer of 621A-80, TPGDA and styrene as the matrix doped with PPO and POPOP. Its fluorescence spectra displayed a maximum emission wavelength at 428 nm. The light yield of the plastic scintillator was approximately 7.1% of anthracene on the basis of a comparison with the commercially available scintillator (ST-401). The as-prepared plastic scintillator also displayed a fast scintillation decay. Its decay time is 2.6 ns approximately. Importantly, through the technology of photosensitivity rapid prototyping, the plastic scintillator could be prepared in a short period of time at low temperature. What's more, this preparation method provides the possibility of combining the plastic scintillator with 3D printing technology, and then the applications of the plastic scintillator may be expanded greatly.

  19. The Plastic Scintillator Detector of the DAMPE space experiment

    NASA Astrophysics Data System (ADS)

    Sun, Zhiyu

    2016-07-01

    The DArk Matter Explorer (DAMPE) is a satellite based experiment aiming for dark matter search and many other topics astronomy interested. The Plastic Scintillator Detector (PSD) gives DAMPE the ability to measure charge of the crossing particles and separate gamma from electrons, which are necessary for achieving the goals of the experiment. The PSD is composed by 82 scintillator counters and read at both ends by a total of 162 photomultiplier tubes. In this paper, we describe the final design of DAMPE-PSD, the expected performances, and shows some results of the beam test carried on at CERN.

  20. The readout electronics for Plastic Scintillator Detector of DAMPE

    NASA Astrophysics Data System (ADS)

    Kong, Jie; Yang, Haibo; Zhao, Hongyun; Su, Hong; Sun, Zhiyu; Yu, Yuhong; JingZhe, Zhang; Wang, XiaoHui; Liu, Jie; Xiao, Guoqing; Ma, Xinwen

    2016-07-01

    The Dark Matter Particle Explorer (DAMPE) satellite, which launched in December 2015, is designed to find the evidence of the existence of dark matter particles in the universe via the detection of the high-energy electrons and gamma-ray particles produced possibly by the annihilation of dark matter particles. Plastic Scintillator Detector (PSD) is one of major part of the satellite payload, which is comprised of a crossed pair of layers with 41 plastic scintillator-strips, each read out from both ends by the same Hamamatsu R4443MOD2 photo-multiplier tubes (PMTs). In order to extend linear dynamic range of detector, PMTs read out each plastic scintillator-strip separately with two dynode pickoffs. Therefore, the readout electronics system comprises of four Front-end boards to receive the pulses from 328 PMTs and implement charge measurement, which is based on the Application Specific Integrated Circuit (ASIC) chip VA160, 16 bits ADC and FPGA. The electronics of the detector has been designed following stringent requirements on mechanical and thermal stability, power consumption, radiation hardness and double redundancy. Various experiments are designed and implemented to check the performance of the electronics, some excellent results has been achieved.According to experimental results analysis, it is proved that the readout electronics works well.

  1. Modelling plastic scintillator response to gamma rays using light transport incorporated FLUKA code.

    PubMed

    Ranjbar Kohan, M; Etaati, G R; Ghal-Eh, N; Safari, M J; Afarideh, H; Asadi, E

    2012-05-01

    The response function of NE102 plastic scintillator to gamma rays has been simulated using a joint FLUKA+PHOTRACK Monte Carlo code. The multi-purpose particle transport code, FLUKA, has been responsible for gamma transport whilst the light transport code, PHOTRACK, has simulated the transport of scintillation photons through scintillator and lightguide. The simulation results of plastic scintillator with/without light guides of different surface coverings have been successfully verified with experiments.

  2. A new tritiated water measurement method with plastic scintillator pellets.

    PubMed

    Furuta, Etsuko; Iwasaki, Noriko; Kato, Yuka; Tomozoe, Yusuke

    2016-01-01

    A new tritiated water measurement method with plastic scintillator pellets (PS-pellets) by using a conventional liquid scintillation counter was developed. The PS-pellets used were 3 mm in both diameter and length. A low potassium glass vial was filled full with the pellets, and tritiated water was applied to the vial from 5 to 100 μl. Then, the sample solution was scattered in the interstices of the pellets in a vial. This method needs no liquid scintillator, so no liquid organic waste fluid is generated. The counting efficiency with the pellets was approximately 48 % when a 5 μl solution was used, which was higher than that of conventional measurement using liquid scintillator. The relationship between count rate and activity showed good linearity. The pellets were able to be used repeatedly, so few solid wastes are generated with this method. The PS-pellets are useful for tritiated water measurement; however, it is necessary to develop a new device which can be applied to a larger volume and measure low level concentration like an environmental application. PMID:26856930

  3. Systematic evaluation of photodetector performance for plastic scintillation dosimetry

    SciTech Connect

    Boivin, Jonathan Beaulieu, Luc; Beddar, Sam; Guillemette, Maxime

    2015-11-15

    Purpose: The authors’ objective was to systematically assess the performance of seven photodetectors used in plastic scintillation dosimetry. The authors also propose some guidelines for selecting an appropriate detector for a specific application. Methods: The plastic scintillation detector (PSD) consisted of a 1-mm diameter, 10-mm long plastic scintillation fiber (BCF-60), which was optically coupled to a clear 10-m long optical fiber of the same diameter. A light-tight plastic sheath covered both fibers and the scintillator end was sealed. The clear fiber end was connected to one of the following photodetectors: two polychromatic cameras (one with an optical lens and one with a fiber optic taper replacing the lens), a monochromatic camera with an optical lens, a PIN photodiode, an avalanche photodiode (APD), or a photomultiplier tube (PMT). A commercially available W1 PSD was also included in the study, but it relied on its own fiber and scintillator. Each PSD was exposed to both low-energy beams (120, 180, and 220 kVp) from an orthovoltage unit and high-energy beams (6 and 23 MV) from a linear accelerator. Various dose rates were tested to identify the operating range and accuracy of each photodetector. Results: For all photodetectors, the relative uncertainty was less than 5% for dose rates higher than 3 mGy/s. The cameras allowed multiple probes to be used simultaneously, but they are less sensitive to low-light signals. The PIN, APD, and PMT had higher sensitivity, making them more suitable for low dose rate and out-of-field dose monitoring. The relative uncertainty of the PMT was less than 1% at the lowest dose rate achieved (0.10 mGy/s), suggesting that it was optimal for use in live dosimetry. Conclusions: For dose rates higher than 3 mGy/s, the PIN diode is the most effective photodetector in terms of performance/cost ratio. For lower dose rates, such as those seen in interventional radiology or high-gradient radiotherapy, PMTs are the optimal choice.

  4. Synthesis of plastic scintillation microspheres: alpha/beta discrimination.

    PubMed

    Santiago, L M; Bagán, H; Tarancón, A; Garcia, J F

    2014-11-01

    Plastic scintillation microspheres (PSm) have been developed as an alternative for liquid scintillation cocktails due to their ability to avoid the mixed waste, besides other strengths in which the possibility for alpha/beta discrimination is included. The aim of this work was to evaluate the capability of PSm containing two combinations of fluorescence solutes (PPO/POPOP and pT/Bis-MSB) and variable amounts of a second organic solvent (naphthalene) to enhance the alpha/beta discrimination. Two commercial detectors with different Pulse Shape Discrimination performances (Quantulus and Triathler) were used to evaluate the alpha/beta discrimination. An optimal discrimination of alpha/beta particles was reached, with very low misclassification values (2% for beta particles and 0.5% for alpha particles), when PSm containing PPO/POPOP and between 0.6 and 2.0 g of naphthalene were evaluated using Triathler and the appropriate programme for data processing.

  5. Comparing the response of PSD-capable plastic scintillator to standard liquid scintillator

    NASA Astrophysics Data System (ADS)

    Woolf, Richard S.; Hutcheson, Anthony L.; Gwon, Chul; Phlips, Bernard F.; Wulf, Eric A.

    2015-06-01

    This work discusses a test campaign to characterize the response of the recently developed plastic scintillator with pulse shape discrimination (PSD) capabilities (EJ-299-33). PSD is a property exhibited by certain types of scintillating material in which incident stimuli (fast neutrons or γ rays) can be separated by exploiting differences in the scintillation light pulse tail. Detector geometries used were: a 10 cm×10 cm×10 cm cube and a 10-cm diameter×10-cm long cylinder. EJ-301 and EJ-309 liquid scintillators with well-known responses were also tested. The work was conducted at the University of Massachusetts Lowell Van De Graaff accelerator. The facility accelerated protons on a thin Li target to yield quasi-monoenergetic neutrons from the 7Li(p,n)7Be reaction (Q-value: -1.644 MeV). Collimated fast neutrons were obtained by placing detectors behind a neutron spectrometer. Rotating the spectrometer, and thus changing the neutron energy, allowed us to achieve 0.5-3.2 MeV neutrons in 200-300 keV steps. Data were acquired through a flash analog-to-digital converter (ADC) capable of performing digital PSD measurements. By using the PSD technique to separate the neutron events from unwanted γ background, we constructed a pulse height spectrum at each energy. Obtaining a relationship of the relative light output versus energy allowed us to construct the response function for the EJ-299-33 and liquid scintillator. The EJ-299-33 response in terms of electron equivalent energy (Ee.e.) vs. proton equivalent energy (Ep.e.), how it compared with the standard xylene-based EJ-301 (or, NE-213/BC-501 A equivalent) and EJ-309 liquid scintillator response, and how the EJ-301 and EJ-309 compared, are presented. We find that the EJ-299-33 demonstrated a lower light output by up to 40% for <1.0 MeV neutrons; and ranging between a 5-35% reduction for 2.5-3.0 MeV neutrons compared to the EJ-301/309, depending on the scintillator and geometry. Monte Carlo modeling techniques were

  6. Simulation results of liquid and plastic scintillator detectors for reactor antineutrino detection - A comparison

    NASA Astrophysics Data System (ADS)

    Kashyap, V. K. S.; Pant, L. M.; Mohanty, A. K.; Datar, V. M.

    2016-03-01

    A simulation study of two kinds of scintillation detectors has been done using GEANT4. We compare plastic scintillator and liquid scintillator based designs for detecting electron antineutrinos emitted from the core of reactors. The motivation for this study is to set up an experiment at the research reactor facility at BARC for very short baseline neutrino oscillation study and remote reactor monitoring.

  7. Review of plastic and liquid scintillation dosimetry for photon, electron, and proton therapy

    NASA Astrophysics Data System (ADS)

    Beaulieu, Luc; Beddar, Sam

    2016-10-01

    While scintillation dosimetry has been around for decades, the need for a dosimeter tailored to the reality of modern radiation therapy—in particular a real-time, water-equivalent, energy-independent dosimeter with high spatial resolution—has generated renewed interest in scintillators over the last 10 years. With the advent of at least one commercial plastic scintillation dosimeter and the ever-growing scientific literature on this subject, this topical review is intended to provide the medical physics community with a wide overview of scintillation physics, related optical concepts, and applications of plastic scintillation dosimetry.

  8. Study and understanding of n/γ discrimination processes in organic plastic scintillators

    NASA Astrophysics Data System (ADS)

    Hamel, Matthieu; Blanc, Pauline; Rocha, Licinio; Normand, Stéphane; Pansu, Robert

    2013-05-01

    For 50 years, it was assumed that unlike liquid scintillators or organic crystals, plastic scintillators were not able to discriminate fast neutrons from gamma. In this work, we will demonstrate that triplet-triplet annihilations (which are responsible of n/γ discrimination) can occur even in plastic scintillators, following certain conditions. Thus, the presentation will deal with the chemical preparation, the characterization and the comparison of n/γ pulse shape discrimination of various plastic scintillators. To this aim, scale-up of the process allowed us to prepare a Ø 100 mm × ≈ 110 mm thick.

  9. Neutron/gamma pulse shape discrimination (PSD) in plastic scintillators with digital PSD electronics

    NASA Astrophysics Data System (ADS)

    Hutcheson, Anthony L.; Simonson, Duane L.; Christophersen, Marc; Phlips, Bernard F.; Charipar, Nicholas A.; Piqué, Alberto

    2013-05-01

    Pulse shape discrimination (PSD) is a common method to distinguish between pulses produced by gamma rays and neutrons in scintillator detectors. This technique takes advantage of the property of many scintillators that excitations by recoil protons and electrons produce pulses with different characteristic shapes. Unfortunately, many scintillating materials with good PSD properties have other, undesirable properties such as flammability, toxicity, low availability, high cost, and/or limited size. In contrast, plastic scintillator detectors are relatively low-cost, and easily handled and mass-produced. Recent studies have demonstrated efficient PSD in plastic scintillators using a high concentration of fluorescent dyes. To further investigate the PSD properties of such systems, mixed plastic scintillator samples were produced and tested. The addition of up to 30 wt. % diphenyloxazole (DPO) and other chromophores in polyvinyltoluene (PVT) results in efficient detection with commercial detectors. These plastic scintillators are produced in large diameters up to 4 inches by melt blending directly in a container suitable for in-line detector use. This allows recycling and reuse of materials while varying the compositions. This strategy also avoids additional sample handling and polishing steps required when using removable molds. In this presentation, results will be presented for different mixed-plastic compositions and compared with known scintillating materials

  10. The impact of fluorescent dyes on the performances of polystyrene-based plastic scintillators

    NASA Astrophysics Data System (ADS)

    Zhu, Jun; Deng, Cheng; Jiang, Huimin; Zheng, Zhanlong; Gong, Rui; Bi, Yutie; Zhang, Lin; Lin, Runxiong

    2016-11-01

    To investigate the influence of both the first luminescent additive and the wavelength-shifter on the performance of plastic scintillator, a series of polystyrene-based scintillator had been prepared by thermal polymerization. Three first luminescent additives (PPO, p-TP and b-PBD) and four wavelength-shifters (POPOP, Bis-MSB, Me-MSB and DPA) were added to the scintillators respectively. The comparison results showed that PPO and POPOP were the most adequate fluorescent dyes for the polystyrene-based plastic scintillator. Moreover, with the increase of the concentration of PPO and POPOP, the fluorescence intensity and light yield were increased firstly and then decreased. The plastic scintillator containing 2% PPO and 0.02% POPOP had the highest fluorescence intensity and light yield.

  11. A plastic scintillator film for an electron beam-excitation assisted optical microscope

    NASA Astrophysics Data System (ADS)

    Inami, Wataru; Fukuta, Masahiro; Masuda, Yuriko; Nawa, Yasunori; Ono, Atsushi; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

    2015-04-01

    A plastic scintillator film for use in an electron beam excitation-assisted (EXA) optical microscope is characterized. The thin film scatters an incident electron beam weakly and generates high intensity nanoscale luminescence excited by the beam spot. For high spatial resolution and signal to noise, an EXA microscope requires a thin high-efficiency scintillator film. Homogeneous plastic scintillators with thicknesses ranging from 60 to 2800 nm were fabricated on silicon nitride via spin coating. The emission intensity was examined as a function of film thickness and the accelerating voltage of the incident electron beam. The emission wavelength can be tuned by changing scintillator materials in the film matrix. To demonstrate a plastic scintillator film performance with an EXA microscope, time-lapse images of yeast cells were acquired.

  12. Photon dosimetry using plastic scintillators in pulsed radiation fields

    SciTech Connect

    David L. Chichester; Brandon W. Blackburn; James T. Johnson; Scott W. Watson

    2007-04-01

    Simulations and experiments have been carried out to explore using a plastic scintillator as a dosimetry probe in the vicinity of a pulsed bremsstrahlung source in the range 4 to 20 MeV. Taking advantage of the tissue-equivalent properties of this detector in conjunction with the use of a fast digital signal processor near real-time dosimetry was shown to be possible. The importance of accounting for a broad energy electron beam in bremsstrahlung production, and photon scattering and build-up, in correctly interpreting dosimetry results at long stand-off distances is highlighted by comparing real world experiments with ideal geometry simulations. Close agreement was found between absorbed energy calculations based upon spectroscopic techniques and calculations based upon signal integration, showing a ratio between 10 MeV absorbed dose to 12 MeV absorbed dose of 0.66 at a distance of 91.4 m from the accelerator. This is compared with an idealized model simulation with a monoenergetic electron beam and without scattering, where the ratio was 0.46.

  13. CALCULATION OF GAMMA SPECTRA IN A PLASTIC SCINTILLATOR FOR ENERGY CALIBRATIONAND DOSE COMPUTATION.

    PubMed

    Kim, Chankyu; Yoo, Hyunjun; Kim, Yewon; Moon, Myungkook; Kim, Jong Yul; Kang, Dong Uk; Lee, Daehee; Kim, Myung Soo; Cho, Minsik; Lee, Eunjoong; Cho, Gyuseong

    2016-09-01

    Plastic scintillation detectors have practical advantages in the field of dosimetry. Energy calibration of measured gamma spectra is important for dose computation, but it is not simple in the plastic scintillators because of their different characteristics and a finite resolution. In this study, the gamma spectra in a polystyrene scintillator were calculated for the energy calibration and dose computation. Based on the relationship between the energy resolution and estimated energy broadening effect in the calculated spectra, the gamma spectra were simply calculated without many iterations. The calculated spectra were in agreement with the calculation by an existing method and measurements. PMID:27127208

  14. The plastic scintillator detector calibration circuit for DAMPE

    NASA Astrophysics Data System (ADS)

    Yang, Haibo; Kong, Jie; Zhao, Hongyun; Su, Hong

    2016-07-01

    The Dark Matter Particle Explorer (DAMPE) is being constructed as a scientific satellite to observe high energy cosmic rays in space. Plastic scintillator detector array (PSD), developed by Institute of Modern Physics, Chinese Academy of Sciences (IMPCAS), is one of the most important parts in the payload of DAMPE which is mainly used for the study of dark matter. As an anti-coincidence detector, and a charged-particle identification detector, the PSD has a total of 360 electronic readout channels, which are distributed at four sides of PSD using four identical front end electronics (FEE). Each FEE reads out 90 charge signals output by the detector. A special calibration circuit is designed in FEE. FPGA is used for on-line control, enabling the calibration circuit to generate the pulse signal with known charge. The generated signal is then sent to the FEE for calibration and self-test. This circuit mainly consists of DAC, operation amplifier, analog switch, capacitance and resistance. By using controllable step pulse, the charge can be coupled to the charge measuring chip using the small capacitance. In order to fulfill the system's objective of large dynamic range, the FEE is required to have good linearity. Thus, the charge-controllable signal is needed to do sweep test on all channels in order to obtain the non-linear parameters for off-line correction. On the other hand, the FEE will run on the satellite for three years. The changes of the operational environment and the aging of devices will lead to parameter variation of the FEE, highlighting the need for regular calibration. The calibration signal generation circuit also has a compact structure and the ability to work normally, with the PSD system's voltage resolution being higher than 0.6%.

  15. SU-E-CAMPUS-T-03: Four-Dimensional Dose Distribution Measurement Using Plastic Scintillator

    SciTech Connect

    Hashimoto, M; Kozuka, T; Oguchi, M; Nishio, T; Haga, A; Hanada, T; Kabuki, S

    2014-06-15

    Purpose: To develop the detector for the four-dimensional dose distribution measurement. Methods: We made the prototype detector for four-dimensional dose distribution measurement using a cylindrical plastic scintillator (5 cm diameter) and a conical reflection grass. The plastic scintillator is used as a phantom. When the plastic scintillator is irradiated, the scintillation light was emitted according to absorbed dose distribution. The conical reflection grass was arranged to surround the plastic scintillator, which project to downstream the projection images of the scintillation light. Then, the projection image was reflected to 45 degree direction by flat reflection grass, and was recorded by camcorder. By reconstructing the three-dimensional dose distribution from the projection image recorded in each frame, we could obtain the four-dimensional dose distribution. First, we tested the characteristic according to the amount of emitted light. Then we compared of the light profile and the dose profile calculated with the radiotherapy treatment planning system. Results: The dose dependency of the amount of light showed linearity. The pixel detecting smaller amount of light had high sensitivity than the pixel detecting larger amount of light. However the difference of the sensitivity could be corrected from the amount of light detected in each pixel. Both of the depth light profile through the conical reflection grass and the depth dose profile showed the same attenuation in the region deeper than peak depth. In lateral direction, the difference of the both profiles was shown at outside field and penumbra region. We consider that the difference is occurred due to the scatter of the scintillation light in the plastic scintillator block. Conclusion: It was possible to obtain the amount of light corresponding to the absorbed dose distribution from the prototype detector. Four-dimensional dose distributions can be reconstructed with high accuracy by the correction of

  16. Surface preparation and coupling in plastic scintillator dosimetry.

    PubMed

    Ayotte, Guylaine; Archambault, Louis; Gingras, Luc; Lacroix, Frédéric; Beddar, A Sam; Beaulieu, Luc

    2006-09-01

    One way to improve the performance of scintillation dosimeters is to increase the light-collection efficiency at the coupling interfaces of the detector system. We performed a detailed study of surface preparation of scintillating fibers and their coupling with clear optical fibers to minimize light loss and increase the amount of light collected. We analyzed fiber-surface polishing with aluminum oxide sheets, coating fibers with magnesium oxide, and the use of eight different coupling agents (air, three optical gels, an optical curing agent, ultraviolet light, cyanoacrylate glue, and acetone). We prepared 10 scintillating fiber and clear optical fiber light guide samples to test different coupling methods. To test the coupling, we first cut both the scintillating fiber and the clear optical fiber. Then, we cleaned and polished both ends of both fibers. Finally, we coupled the scintillating fiber with the clear optical fiber in either a polyethylene jacket or a V-grooved support depending on the coupling agent used. To produce more light, we used an ultraviolet lamp to stimulate scintillation. A typical series of similar couplings showed a standard deviation in light-collection efficiency of 10%. This can be explained by differences in the surface preparation quality and alignment of the scintillating fiber with the clear optical fiber. Absence of surface polishing reduced the light collection by approximately 40%, and application of magnesium oxide on the proximal end of the scintillating fiber increased the amount of light collected from the optical fiber by approximately 39%. Of the coupling agents, we obtained the best results using one of the optical gels. Because a large amount of the light produced inside a scintillator is usually lost, better light-collection efficiency will result in improved sensitivity. PMID:17022248

  17. Surface preparation and coupling in plastic scintillator dosimetry

    SciTech Connect

    Ayotte, Guylaine; Archambault, Louis; Gingras, Luc; Lacroix, Frederic; Beddar, A. Sam; Beaulieu, Luc

    2006-09-15

    One way to improve the performance of scintillation dosimeters is to increase the light-collection efficiency at the coupling interfaces of the detector system. We performed a detailed study of surface preparation of scintillating fibers and their coupling with clear optical fibers to minimize light loss and increase the amount of light collected. We analyzed fiber-surface polishing with aluminum oxide sheets, coating fibers with magnesium oxide, and the use of eight different coupling agents (air, three optical gels, an optical curing agent, ultraviolet light, cyanoacrylate glue, and acetone). We prepared 10 scintillating fiber and clear optical fiber light guide samples to test different coupling methods. To test the coupling, we first cut both the scintillating fiber and the clear optical fiber. Then, we cleaned and polished both ends of both fibers. Finally, we coupled the scintillating fiber with the clear optical fiber in either a polyethylene jacket or a V-grooved support depending on the coupling agent used. To produce more light, we used an ultraviolet lamp to stimulate scintillation. A typical series of similar couplings showed a standard deviation in light-collection efficiency of 10%. This can be explained by differences in the surface preparation quality and alignment of the scintillating fiber with the clear optical fiber. Absence of surface polishing reduced the light collection by approximately 40%, and application of magnesium oxide on the proximal end of the scintillating fiber increased the amount of light collected from the optical fiber by approximately 39%. Of the coupling agents, we obtained the best results using one of the optical gels. Because a large amount of the light produced inside a scintillator is usually lost, better light-collection efficiency will result in improved sensitivity.

  18. A plastic scintillating fiber position detector in vacuum for the test beam facility at BEPC II -LINAC

    NASA Astrophysics Data System (ADS)

    Ke, Zun-Jian; Li, Jia-Cai; Zhang, Shao-Ping; An, Guang-Peng; Tang, Xing-Hua; Yang, Tao

    2012-01-01

    Two plastic scintillating fiber position detectors for charged particles have been designed, built and installed inside the vacuum tube near two sides of the DM2 deflection magnet on the E3 beam line of the test beam facility at the BEPC-LINAC. A one-dimensional position resolution of ~1 mm with a sensitive area of 60 mm×60 mm has been obtained for this detector.

  19. First performance test of newly developed plastic scintillator for radiation detection

    NASA Astrophysics Data System (ADS)

    Watanabe, M.; Katsumata, M.; Ono, H.; Suzuki, T.; Miyata, H.; Itoh, Y.; Ishida, K.; Tamura, M.; Yamaguchi, Y.

    2015-01-01

    We present a plastic scintillator, developed in collaboration with Carlit Holdings Co., Ltd., that is fabricated using a liquid parent material cured at room temperature by adding a hardener. The new scintillator can incorporate heat-labile functional materials such as gadolinium to enhance neutron sensitivity. The characteristics of the new scintillator, in particular the light yield and attenuation length, were evaluated using a 90Sr β-ray source. The light yield was measured 7% Anthracene on the basis of a comparison with commercially available scintillator (BC-408) at a distance of 18 cm from the photodetector surface. This light yield is dependent on the distance between the luminous point and the photodetector because of light attenuation. The attenuation length of the Gd-doped scintillator was about 50 cm.

  20. Reaching time resolution of less than 10 ps with plastic scintillation detectors

    NASA Astrophysics Data System (ADS)

    Zhao, J. W.; Sun, B. H.; Tanihata, I.; Terashima, S.; Zhu, L. H.; Enomoto, A.; Nagae, D.; Nishimura, T.; Omika, S.; Ozawa, A.; Takeuchi, Y.; Yamaguchi, T.

    2016-07-01

    Timing-pick up detectors with excellent timing resolutions are essential in many modern nuclear physics experiments. Aiming to develop a Time-Of-Flight system with precision down to about 10 ps, we have made a systematic study of the timing characteristic of TOF detectors, which consist of several combinations of plastic scintillators and photomultiplier tubes. With the conventional electronics, the best timing resolution of about 5.1 ps (σ) has been achieved for detectors with an area size of 3 × 1cm2 . It is found that for data digitalization a combination of TAC and ADC can achieve a better time resolution than the currently available TDC. Simultaneous measurements of both time and pulse height are very valuable for the correction of time-walk effect.

  1. A systematic characterization of the low-energy photon response of plastic scintillation detectors.

    PubMed

    Boivin, Jonathan; Beddar, Sam; Bonde, Chris; Schmidt, Daniel; Culberson, Wesley; Guillemette, Maxime; Beaulieu, Luc

    2016-08-01

    To characterize the low energy behavior of scintillating materials used in plastic scintillation detectors (PSDs), 3 PSDs were developed using polystyrene-based scintillating materials emitting in different wavelengths. These detectors were exposed to National Institute of Standards and Technology (NIST)-matched low-energy beams ranging from 20 kVp to 250 kVp, and to (137)Cs and (60)Co beams. The dose in polystyrene was compared to the dose in air measured by NIST-calibrated ionization chambers at the same location. Analysis of every beam quality spectrum was used to extract the beam parameters and the effective mass energy-absorption coefficient. Monte Carlo simulations were also performed to calculate the energy absorbed in the scintillators' volume. The scintillators' expected response was then compared to the experimental measurements and an energy-dependent correction factor was identified to account for low-energy quenching in the scintillators. The empirical Birks model was then compared to these values to verify its validity for low-energy electrons. The clear optical fiber response was below 0.2% of the scintillator's light for x-ray beams, indicating that a negligible amount of fluorescence contamination was produced. However, for higher-energy beams ((137)Cs and (60)Co), the scintillators' response was corrected for the Cerenkov stem effect. The scintillators' response increased by a factor of approximately 4 from a 20 kVp to a (60)Co beam. The decrease in sensitivity from ionization quenching reached a local minimum of about [Formula: see text] between 40 keV and 60 keV x-ray beam mean energy, but dropped by 20% for very low-energy (13 keV) beams. The Birks model may be used to fit the experimental data, but it must take into account the energy dependence of the kB quenching parameter. A detailed comprehension of intrinsic scintillator response is essential for proper calibration of PSD dosimeters for radiology.

  2. Iterative Monte Carlo simulation with the Compton kinematics-based GEB in a plastic scintillation detector

    NASA Astrophysics Data System (ADS)

    Kim, Chankyu; Kim, Yewon; Moon, Myungkook; Cho, Gyuseong

    2015-09-01

    Plastic scintillators have been used for gamma ray detection in the fields of dosimetry and homeland security because of their desired characteristics such as a fast decay time, a low production cost, availability in a large-scale, and a tissue-equivalence. Gaussian energy broadening (GEB) in MCNP simulation is an effective treatment for tallies to calculate the broadened response function of a detector similarly to measured spectra. The full width at half maximum (FWHM) of a photopeak has been generally used to compute input parameters required for the GEB treatment. However, it is hard to find the photopeak in measured gamma spectra with plastic scintillators so that computation of the input parameters for the GEB has to be taken with another way. In this study, an iterative method for the GEB treated MCNP simulation to calculate the response function of a plastic scintillator is suggested. Instead of the photopeak, Compton maximum and Compton edge were used to estimate energy broadening in the measured spectra and to determine the GEB parameters. In a demonstration with a CsI(Tl) scintillator, the proposed iterative simulation showed the similar gamma spectra to the existing method using photopeaks. The proposed method was then applied to a polystyrene scintillator, and the simulation result were in agreement with the measured spectra with only a little iteration.

  3. Reactor antineutrino monitoring with a plastic scintillator array as a new safeguards method

    NASA Astrophysics Data System (ADS)

    Oguri, S.; Kuroda, Y.; Kato, Y.; Nakata, R.; Inoue, Y.; Ito, C.; Minowa, M.

    2014-09-01

    We developed a segmented reactor-antineutrino detector made of plastic scintillators for application as a tool in nuclear safeguards inspection and performed mostly unmanned field operations at a commercial power plant reactor. At a position outside the reactor building, we measured the difference in reactor antineutrino flux above the ground when the reactor was active and inactive.

  4. Measurement of (222)Rn by absorption in plastic scintillators and alpha/beta pulse shape discrimination.

    PubMed

    Mitev, Krasimir K

    2016-04-01

    This work demonstrates that common plastic scintillators like BC-400, EJ-200 and SCSF-81 absorb radon and their scintillation pulse decay times are different for alpha- and beta-particles. This allows the application of pulse shape analysis for separation of the pulses of alpha- and beta-particles emitted by the absorbed radon and its progeny. It is shown that after pulse shape discrimination of beta-particles' pulses, the energy resolution of BC-400 and EJ-200 alpha spectra is sufficient to separate the peaks of (222)Rn, (218)Po and (214)Po and allows (222)Rn measurements that are unaffected by the presence of thoron ((220)Rn) in the environment. The alpha energy resolution of SCSF-81 in the experiments degrades due to imperfect collection of the light emitted inside the scintillating fibers. The experiments with plastic scintillation microspheres (PSM) confirm previous findings of other researchers that PSM have alpha-/beta-discrimination properties and show suitability for radon measurements. The diffusion length of radon in BC-400 and EJ-200 is determined. The pilot experiments show that the plastic scintillators are suitable for radon-in-soil-gas measurements. Overall, the results of this work suggest that it is possible to develop a new type of radon measurement instruments which employ absorption in plastic scintillators, pulse-shape discrimination and analysis of the alpha spectra. Such instruments can be very compact and can perform continuous, real-time radon measurements and thoron detection. They can find applications in various fields from radiation protection to earth sciences. PMID:26851823

  5. Neutron response characterization for an EJ299-33 plastic scintillation detector

    SciTech Connect

    Lawrence, Chris C.; Febbraro, Michael; Massey, Thomas N.; Flaska, Marek; Becchetti, F. D.; Pozzi, Sara A.

    2014-05-10

    Organic scintillation detectors have shown promise as neutron detectors for characterizing special nuclear materials in various arms-control and homeland security applications. Recent advances have yielded a new plastic scintillator - EJ299-33 - with pulse-shape-discrimination (PSD) capability. Plastic scintillators would have a much expanded range of deployment relative to liquids and crystals. Here, we present a full characterization of pulse height response to fission-energy neutrons for an EJ299-33 detector with 7.62-by-7.62-cm cylindrical active volume, and compare with an EJ309 liquid scintillator in the same assembly. Scintillation light output relations, energy resolutions, and response matrices are presented for both detectors. A Continuous spectrum neutron source, obtained via the bombardment of Al-27 with 7.44-MeV deuterons at the Edwards Accelerator Facility at Ohio University, was used for the measurement. A new procedure for evaluating and comparing PSD performance is presented which accounts for the effect of the light output relation on the ability to detect low energy neutrons. The EJ299-33 is shown to have considerable deficit in matrix condition, and in PSD figure of merit when compared to EJ309, especially when neutron energy is taken into account. Furthermore the EJ299 is likely to bring a modest PSD capability into a array of held applications that are not accessible to liquids or crystals. (C) 2014 Elsevier B.V. All rights reserved. Keywords

  6. Neutron response characterization for an EJ299-33 plastic scintillation detector

    DOE PAGES

    Lawrence, Chris C.; Febbraro, Michael; Massey, Thomas N.; Flaska, Marek; Becchetti, F. D.; Pozzi, Sara A.

    2014-05-10

    Organic scintillation detectors have shown promise as neutron detectors for characterizing special nuclear materials in various arms-control and homeland security applications. Recent advances have yielded a new plastic scintillator - EJ299-33 - with pulse-shape-discrimination (PSD) capability. Plastic scintillators would have a much expanded range of deployment relative to liquids and crystals. Here, we present a full characterization of pulse height response to fission-energy neutrons for an EJ299-33 detector with 7.62-by-7.62-cm cylindrical active volume, and compare with an EJ309 liquid scintillator in the same assembly. Scintillation light output relations, energy resolutions, and response matrices are presented for both detectors. A Continuousmore » spectrum neutron source, obtained via the bombardment of Al-27 with 7.44-MeV deuterons at the Edwards Accelerator Facility at Ohio University, was used for the measurement. A new procedure for evaluating and comparing PSD performance is presented which accounts for the effect of the light output relation on the ability to detect low energy neutrons. The EJ299-33 is shown to have considerable deficit in matrix condition, and in PSD figure of merit when compared to EJ309, especially when neutron energy is taken into account. Furthermore the EJ299 is likely to bring a modest PSD capability into a array of held applications that are not accessible to liquids or crystals. (C) 2014 Elsevier B.V. All rights reserved. Keywords« less

  7. Neutron response characterization for an EJ299-33 plastic scintillation detector

    NASA Astrophysics Data System (ADS)

    Lawrence, Chris C.; Febbraro, Michael; Massey, Thomas N.; Flaska, Marek; Becchetti, F. D.; Pozzi, Sara A.

    2014-09-01

    Organic scintillation detectors have shown promise as neutron detectors for characterizing special nuclear materials in various arms-control and homeland-security applications. Recent advances have yielded a new plastic scintillator - EJ299-33 - with pulse-shape-discrimination (PSD) capability. Plastic scintillators would have a much-expanded range of deployment relative to liquids and crystals. Here, we present a full characterization of pulse-height response to fission-energy neutrons for an EJ299-33 detector with 7.62-by-7.62-cm cylindrical active volume, and compare with an EJ309 liquid scintillator in the same assembly. Scintillation light-output relations, energy resolutions, and response matrices are presented for both detectors. A continuous-spectrum neutron source, obtained via the bombardment of 27Al with 7.44-MeV deuterons at the Edwards Accelerator Facility at Ohio University, was used for the measurement. A new procedure for evaluating and comparing PSD performance is presented which accounts for the effect of the light-output relation on the ability to detect low-energy neutrons. The EJ299-33 is shown to have considerable deficit in matrix condition, and in PSD figure of merit when compared to EJ309, especially when neutron energy is taken into account. Nevertheless the EJ299 is likely to bring a modest PSD capability into a array of field applications that are not accessible to liquids or crystals.

  8. Accounting for self-absorption in calculation of light collection in plastic scintillators

    NASA Astrophysics Data System (ADS)

    Senchyshyn, V.; Lebedev, V.; Adadurov, A.; Budagov, J.; Chirikov-Zorin, I.

    2006-10-01

    This paper concerns Monte Carlo calculations of light collection in plastic scintillators with accounting for self-absorption. Two approaches are compared: a monochrome one, which takes into account light absorption at a wavelength of the emission spectra maximum, and a spectral one, which accounts for the absorption dependence on a wave length over the whole range of scintillating photon emission. Both approaches are used in light yield calculations for OPERA and Super-Nemo detectors. It is shown that the monochrome approach overestimates light collection values 1.5-2 times, while the spectral one leads to better agreement with experiment.

  9. Use of water-equivalent plastic scintillator for intravascular brachytherapy dosimetry.

    PubMed

    Geso, M; Robinson, N; Schumer, W; Williams, K

    2004-03-01

    Beta irradiation has recently been investigated as a possible technique for the prevention of restenosis in intravascular brachytherapy after balloon dilatation or stent implantation. Present methods of beta radiation dosimetry are primarily conducted using radiochromic film. These film dosimeters exhibit limited sensitivity and their characteristics differ from those of tissue, therefore the dose measurement readings require correction factors to be applied. In this work a novel, mini-size (2 mm diameter by 5 mm long) dosimeter element fabricated from Organic Plastic Scintillator (OPS) material was employed. Scintillation photon detection is accomplished using a precision photodiode and innovative signal amplification and processing techniques, rather than traditional photomultiplier tube methods. A significant improvement in signal to noise ratio, dynamic range and stability is achieved using this set-up. In addition, use of the non-saturating organic plastic scintillator material as the detector enables the dosimeter to measure beta radiation at very close distances to the source. In this work the plastic scintillators have been used to measure beta radiation dose at distances of less than 1 mm from an Sr-90 cardiovascular brachytherapy source having an activity of about 2.1 GBq beta radiation levels for both depth-distance and longitudinal profile of the source pellet chain, both in air and in liquid water, are measured using this system. The data obtained is compared with results from Monte Carlo simulation technique (MCNP 4B). Plastic scintillator dosimeter elements, when used in conjunction with photodiode detectors may prove to be useful dosimeters for cardiovascular brachytherapy beta sources, or other applications where precise near-source field dosimetry is required. The system described is particularly useful where measurement of actual dose rate in real time, a high level of stability and repeatability, portability, and immediate access to results are

  10. Evaluation of NaI(TL) and plastic scintillators for use in remote, unattended, and portal monitoring

    SciTech Connect

    Staples, P.; Audia, J.; Bai, Y.; Briggs, M.; Halbig, J.K.; Ianakiev, K.D.

    1998-12-31

    The authors have evaluated and compared some of the relevant operating characteristics of NaI and plastic scintillators for use in various safeguards monitoring applications. These include a sensitivity analysis of the two scintillators to various radiation fields and scintillator response as affected by environmental temperature. A comparison of experiment and modeling via the Monte Carlo N-Particle (MCNP) code has been performed to validate the calculational techniques. This then enables complex detector situations to be simulated with increased confidence.

  11. Compensated bismuth-loaded plastic scintillators for neutron detection using low-energy pseudo-spectroscopy

    NASA Astrophysics Data System (ADS)

    Dumazert, Jonathan; Coulon, Romain; Bertrand, Guillaume H. V.; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

    2016-05-01

    Gadolinium-covered modified plastic scintillators show a high potential for the deployment of cost-effective neutron detectors. Taking advantage of the low-energy photon and electron signature of thermal neutron captures in gadolinium-155 and gadolinium-157 however requires a background correction. In order to display a trustable rate, dual compensation schemes appear as an alternative to Pulse Shape Discrimination. This paper presents the application of such a compensation scheme to a two-bismuth loaded plastic scintillator system. A detection scintillator interacts with incident photon and fast neutron radiations and is covered with a gadolinium converter to become thermal neutron-sensitive as well. In the meantime, an identical compensation scintillator, covered with terbium, solely interacts with the photon and fast neutron part of incident radiations. After the acquisition and the treatment of the counting signals from both sensors, a hypothesis test determines whether the resulting count rate after subtraction falls into statistical fluctuations or provides a robust image of neutron activity. A laboratory prototype is tested under both photon and neutron radiations, allowing us to investigate the performance of the overall compensation system. The study reveals satisfactory results in terms of robustness to a cesium-137 background and in terms of sensitivity in presence of a californium-252 source.

  12. Proton beam dosimetry: a comparison between a plastic scintillator, ionization chamber and Faraday cup.

    PubMed

    Ghergherehchi, Mitra; Afarideh, Hossein; Ghannadi, Mohammad; Mohammadzadeh, Ahmad; Aslani, Golam Reza; Boghrati, Behzad

    2010-01-01

    In this study, a comparison was made between a plastic scintillator (BC400), a Faraday Cup (FC) and an ionization chamber (IC) used for routine proton dosimetry. Thin scintillators can be applied to proton dosimetry and consequently to proton therapy as relative dosimeters because of their water-equivalent nature, high energy-light conversion efficiency, low dimensions and good proportionality to the absorbed dose at low stopping powers. To employ such scintillators as relative dosimeters in proton therapy, the corrective factors must be applied to correct the quenching luminescence at the Bragg peak. A fine linear proportionality between the luminescence light yield Y and the proton flux in a thin (0.5 mm) scintillator for the 20 and 30 MeV proton beams were observed. The experimental peak/plateau ratios of Bragg Curve for 2, 1 and 0.5 mm scintillators with an accuracy of 0.5% were obtained to be 1.87, 1.91 and 2.30, respectively. With combination of the Markus chamber and the CR-39 detector, the peak/plateau ratio was improved to 3.26. The obtained data of the luminescence yield as a function of the specific energy loss is in agreement with the Craun-Birk's theory. Results show that the FC and Markus ionization chamber are in agreement within 4%, while the FC gives a lower dose evaluation. For a defined beam, the data for the fluence measurements are reproducible within a good accuracy.

  13. A capture-gated neutron calorimeter using plastic scintillators and 3He drift tubes

    SciTech Connect

    Wang, Zhehui; Morris, Christopher L; Spaulding, Randy J; Bacon, Jeffrey D; Borozdin, Konstantin N; Chung, Kiwhan; Clark, Deborah J; Green, Jesse A; Greene, Steven J; Hogan, Gary E; Jason, Andrew; Lisowski, Paul W; Makela, Mark F; Mariam, Fessaha G; Miyadera, Haruo; Murray, Matthew M; Saunders, Alexander; Wysocki, Frederick J; Gray, Frederick E

    2010-01-01

    A segmented neutron calorimeter using nine 4-inch x 4-inch x 48-inch plastic scintillators and sixteen 2-inch-diameter 48-inch-long 200-mbar-{sup 3}He drift tubes is described. The correlated scintillator and neutron-capture events provide a means for n/{gamma} discrimination, critical to the neutron calorimetry when the {gamma} background is substantial and the {gamma} signals are comparable in amplitude to the neutron signals. A single-cell prototype was constructed and tested. It can distinguish between a {sup 17}N source and a {sup 252}Cf source when the {gamma} and the thermal neutron background are sufficiently small. The design and construction of the nine-cell segmented detector assembly follow the same principle. By recording the signals from individual scintillators, additional {gamma}-subtraction schemes, such as through the time-of-flight between two scintillators, may also be used. The variations of the light outputs from different parts of a scintillator bar are less than 10%.

  14. A systematic characterization of the low-energy photon response of plastic scintillation detectors.

    PubMed

    Boivin, Jonathan; Beddar, Sam; Bonde, Chris; Schmidt, Daniel; Culberson, Wesley; Guillemette, Maxime; Beaulieu, Luc

    2016-08-01

    To characterize the low energy behavior of scintillating materials used in plastic scintillation detectors (PSDs), 3 PSDs were developed using polystyrene-based scintillating materials emitting in different wavelengths. These detectors were exposed to National Institute of Standards and Technology (NIST)-matched low-energy beams ranging from 20 kVp to 250 kVp, and to (137)Cs and (60)Co beams. The dose in polystyrene was compared to the dose in air measured by NIST-calibrated ionization chambers at the same location. Analysis of every beam quality spectrum was used to extract the beam parameters and the effective mass energy-absorption coefficient. Monte Carlo simulations were also performed to calculate the energy absorbed in the scintillators' volume. The scintillators' expected response was then compared to the experimental measurements and an energy-dependent correction factor was identified to account for low-energy quenching in the scintillators. The empirical Birks model was then compared to these values to verify its validity for low-energy electrons. The clear optical fiber response was below 0.2% of the scintillator's light for x-ray beams, indicating that a negligible amount of fluorescence contamination was produced. However, for higher-energy beams ((137)Cs and (60)Co), the scintillators' response was corrected for the Cerenkov stem effect. The scintillators' response increased by a factor of approximately 4 from a 20 kVp to a (60)Co beam. The decrease in sensitivity from ionization quenching reached a local minimum of about [Formula: see text] between 40 keV and 60 keV x-ray beam mean energy, but dropped by 20% for very low-energy (13 keV) beams. The Birks model may be used to fit the experimental data, but it must take into account the energy dependence of the kB quenching parameter. A detailed comprehension of intrinsic scintillator response is essential for proper calibration of PSD dosimeters for radiology. PMID:27384872

  15. Highly lead-loaded red plastic scintillators as an X-ray imaging system for the Laser Mega Joule

    SciTech Connect

    Hamel, M.; Normand, S.; Turk, G.; Darbon, S.

    2011-07-01

    The scope of this project intends to record spatially resolved images of core shape and size of a DT micro-balloon during Inertial Confinement Fusion (ICF) experiments at Laser Mega Joule facility (LMJ). We need to develop an X-ray imaging system which can operate in the radiative background generated by an ignition shot of ICF. The scintillator is a part of the imaging system and has to gather a compromise of scintillating properties (scintillating efficiency, decay time, emission wavelength) so as to both operate in the hard radiative environment and to allow the acquisition of spatially resolved images. Inorganic scintillators cannot be used because no compromise can be found regarding the expected scintillating properties, most of them are not fast enough and emit blue light. Organic scintillators are generally fast, but present low X-ray absorption in the 10 to 40 keV range, that does not permit the acquisition of spatially resolved images. To this aim, we have developed highly lead-loaded and red-fluorescent fast plastic scintillators. Such a combination is not currently available via scintillator suppliers, since they propose only blue-fluorescent plastic scintillators doped with up to 12%w Pb. Thus, incorporation ratio up to 27%w Pb has been reached in our laboratory, which can afford a plastic scintillator with an outstanding Z{sub eff} close to 50. X-rays in the 10 to 40 keV range can thus be detected with a higher probability of photoelectric effect than for classic organic scintillators, such as NE102. The strong orange-red fluorescence can be filtered, so that we can eliminate residual Cerenkov light, generated by {gamma}-ray absorption in glass parts of the imaging system. Decay times of our scintillators evaluated under UV excitation were estimated to be in the range 10 to 13 ns. (authors)

  16. Reference drums used in calibration of a plastic scintillation counter in a 4π counting geometry.

    PubMed

    Yeh, Chin-Hsien; Yuan, Ming-Chen

    2016-03-01

    In this study, two kinds of reference drums were developed. One type was constructed with nine layers of large-area sources filled with different materials having five different densities. The other type of reference drums was constructed with nine rod sources filled with the same materials of different densities. The efficiency calibration of a plastic scintillation counter in 4π counting geometry using these two kinds of drums showed that rod-source drums resulted in higher counting efficiency than layered source drums. The counting rates obtained from rod-source drums were closer to those obtained from a standard drum with water solution than counting rates from drums with layered sources. The results of this study recommend to use reference drums with rod-sources to compensate the drawbacks of standard drums with water solution of not being able to adjust the density of material. The proposed reference drums improve the accuracy of radioactivity analysis for waste drums of different densities. PMID:26651167

  17. Neutron/gamma pulse shape discrimination in plastic scintillators: Preparation and characterization of various compositions

    NASA Astrophysics Data System (ADS)

    Blanc, Pauline; Hamel, Matthieu; Dehé-Pittance, Chrystèle; Rocha, Licinio; Pansu, Robert B.; Normand, Stéphane

    2014-06-01

    This work deals with the preparation and evaluation of plastic scintillators for neutron/gamma pulse shape discrimination (PSD). We succeeded in developing a plastic scintillator with good neutron/gamma discrimination properties in the range of what is already being commercialized. Several combinations of primary and secondary fluorophores were implemented in chemically modified polymers. These scintillators were fully characterized by fluorescence spectroscopy and under neutron irradiation. The materials proved to be stable for up to 5 years without any degradation of PSD properties. They were then classified in terms of their PSD capabilities and light yield. Our best candidate, 28.6 wt% of primary fluorophore with a small amount of secondary fluorophore, shows promising PSD results and is particularly suited to industrial development, because its preparation does not involve the use of expensive or exotic compounds. Furthermore, even at the highest prepared concentration, high stability over time was observed. As a proof of concept, one sample with dimensions 109 mm ∅×114 mm height (≈1 L) was prepared.

  18. Bismuth- and lithium-loaded plastic scintillators for gamma and neutron detection

    NASA Astrophysics Data System (ADS)

    Cherepy, Nerine J.; Sanner, Robert D.; Beck, Patrick R.; Swanberg, Erik L.; Tillotson, Thomas M.; Payne, Stephen A.; Hurlbut, Charles R.

    2015-04-01

    Transparent plastic scintillators based on polyvinyltoluene (PVT) have been fabricated with high loading of bismuth carboxylates for gamma spectroscopy, and with lithium carboxylates for neutron detection. When activated with a combination of standard fluors, 2,5-diphenyloxazole (PPO) and tetraphenylbutadiene (TPB), gamma light yields with 15 wt% bismuth tripivalate of 5000 Ph/MeV are measured. A PVT plastic formulation including 30 wt% lithium pivalate and 30 wt% PPO offers both pulse shape discrimination, and a neutron capture peak at ~400 keVee. In another configuration, a bismuth-loaded PVT plastic is coated with ZnS(6Li) paint, permitting simultaneous gamma and neutron detection via pulse shape discrimination with a figure-of-merit of 3.8, while offering gamma spectroscopy with energy resolution of R(662 keV)=15%.

  19. Dose verification of radiotherapy for lung cancer by using plastic scintillator dosimetry and a heterogeneous phantom

    NASA Astrophysics Data System (ADS)

    Ottosson, W.; Behrens, C. F.; Andersen, C. E.

    2015-01-01

    Bone, air passages, cavities, and lung are elements present in patients, but challenging to properly correct for in treatment planning dose calculations. Plastic scintillator detectors (PSDs) have proven to be well suited for dosimetry in non-reference conditions such as small fields. The objective of this study was to investigate the performance of a commercial treatment planning system (TPS) using a PSD and a specially designed thorax phantom with lung tumor inserts. 10 treatment plans of different complexity and phantom configurations were evaluated. Although the TPS agreed well with the measurements for the least complex tests, deviations of tumor dose > 4% were observed for some cases. This study underpins the dosimetric challenge in TPS calculations for clinically relevant heterogeneous geometries. The scintillator system, together with the special phantom, provides a promising tool for evaluation of complex radiotherapy dose calculations and delivery.

  20. Development of the Plastic Scintillator Detector Array for the Prototype of the Dark Matter Particle Explorer

    NASA Astrophysics Data System (ADS)

    Zhang, Yongjie; Sun, Zhiyu; Yu, Yuhong; Zhou, Yong; Fang, Fang; Chen, Junling

    2016-07-01

    The scientific object of Dark Matter Particles Explorer(DAMPE) is the measurement of electrons and photons in the range of 5GeV~10TeV and the flux of nuclei up to 500TeV with excellent resolution , and the realization of measurements will identify possible Dark Matter(DM) signature and help deepen our understanding of the origin and propagation of high energy cosmic ray respectively. Plastic Scintillator Detector Array (PSD), which adopts perpendicular structure with two layers and each layer consists of 15 scintillator strips, is one sub-detector of DAMPE for detecting heavy ions and distinguishing photons and electrons. In this paper, the design and some test results of PSD are to be described.

  1. Utilization of wavelength-shifting fibers coupled to ZnS(Ag) and plastic scintillator for simultaneous detection of alpha/beta particles

    NASA Astrophysics Data System (ADS)

    Ifergan, Y.; Dadon, S.; Israelashvili, I.; Osovizky, A.; Gonen, E.; Yehuda-Zada, Y.; Smadja, D.; Knafo, Y.; Ginzburg, D.; Kadmon, Y.; Cohen, Y.; Mazor, T.

    2015-06-01

    Low level radioactive surface contamination measurements require lightweight, large area and high efficiency detector. In most existing scintillation detectors there is a tradeoff between effective area and scintillation light collection. By using wavelength shifting (WLS) fibers the scintillation light may be collected efficiently also in a large area detector. In this study, WLS fibers were coupled to a beta sensitive plastic scintillator layer and to a alpha sensitive silver-activated zinc sulfide ZnS(Ag) layer for detecting both alpha and beta particles. The WLS fibers collect the scintillation light from the whole detector and transfer it to a single PMT. This first prototype unique configuration enables monitoring radioactive contaminated surfaces by both sides of the detector and provides high gamma rejection. In this paper, the detector structure, as well as the detector's measured linear response, will be described. The measured detection efficiency of 238Pu alpha particles (5.5 MeV) is ~63%. The measured detection efficiency for beta particles is ~89% for 90Sr-90Y (average energy of 195.8 keV, 934.8 keV), ~50% for 36Cl (average energy of 251.3 keV), and 35% for 137Cs (average energy of 156.8 keV).

  2. Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph.

    PubMed

    Moskal, P; Rundel, O; Alfs, D; Bednarski, T; Białas, P; Czerwiński, E; Gajos, A; Giergiel, K; Gorgol, M; Jasińska, B; Kamińska, D; Kapłon, Ł; Korcyl, G; Kowalski, P; Kozik, T; Krzemień, W; Kubicz, E; Niedźwiecki, Sz; Pałka, M; Raczyński, L; Rudy, Z; Sharma, N G; Słomski, A; Silarski, M; Strzelecki, A; Wieczorek, A; Wiślicki, W; Witkowski, P; Zieliński, M; Zoń, N

    2016-03-01

    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the [Formula: see text] configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the [Formula: see text] matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of [Formula: see text]0.170 ns for 15 cm axial field-of-view (AFOV) and [Formula: see text]0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities. PMID:26895187

  3. Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

    NASA Astrophysics Data System (ADS)

    Moskal, P.; Rundel, O.; Alfs, D.; Bednarski, T.; Białas, P.; Czerwiński, E.; Gajos, A.; Giergiel, K.; Gorgol, M.; Jasińska, B.; Kamińska, D.; Kapłon, Ł.; Korcyl, G.; Kowalski, P.; Kozik, T.; Krzemień, W.; Kubicz, E.; Niedźwiecki, Sz; Pałka, M.; Raczyński, L.; Rudy, Z.; Sharma, N. G.; Słomski, A.; Silarski, M.; Strzelecki, A.; Wieczorek, A.; Wiślicki, W.; Witkowski, P.; Zieliński, M.; Zoń, N.

    2016-03-01

    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2× 5 configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the 2× 5 matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of ≈ 0.170 ns for 15 cm axial field-of-view (AFOV) and ≈ 0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.

  4. Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph.

    PubMed

    Moskal, P; Rundel, O; Alfs, D; Bednarski, T; Białas, P; Czerwiński, E; Gajos, A; Giergiel, K; Gorgol, M; Jasińska, B; Kamińska, D; Kapłon, Ł; Korcyl, G; Kowalski, P; Kozik, T; Krzemień, W; Kubicz, E; Niedźwiecki, Sz; Pałka, M; Raczyński, L; Rudy, Z; Sharma, N G; Słomski, A; Silarski, M; Strzelecki, A; Wieczorek, A; Wiślicki, W; Witkowski, P; Zieliński, M; Zoń, N

    2016-03-01

    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the [Formula: see text] configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the [Formula: see text] matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of [Formula: see text]0.170 ns for 15 cm axial field-of-view (AFOV) and [Formula: see text]0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.

  5. Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

    NASA Astrophysics Data System (ADS)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

    2016-08-01

    Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

  6. TH-C-19A-10: Systematic Evaluation of Photodetectors Performances for Plastic Scintillation Dosimetry

    SciTech Connect

    Boivin, J; Beaulieu, L; Beddar, S; Guillemette, M

    2014-06-15

    Purpose: To assess and compare the performance of different photodetectors likely to be used in a plastic scintillation detector (PSD). Methods: The PSD consists of a 1 mm diameter, 10 mm long plastic scintillation fiber (BCF-60) which is optically coupled to a clear 10 m long optical fiber of the same diameter. A light-tight plastic sheath covers both fibers and the scintillator end is sealed. The clear fiber end is connected to one of the following six studied photodetectors: two polychromatic cameras (one with an optical lens and one with a fiber optic taper replacing the lens); a monochromatic camera with the same optical lens; a PIN photodiode; an avalanche photodiode (APD); and a photomultiplier tube (PMT). Each PSD is exposed to both low energy beams (120, 180, and 220 kVp) from an orthovoltage unit, and high energy beams (6 MV and 23 MV) from a linear accelerator. Various dose rates are explored to identify the photodetectors operating ranges and accuracy. Results: For all photodetectors, the relative uncertainty remains under 5 % for dose rates over 3 mGy/s. The taper camera collects four times more signal than the optical lens camera, although its standard deviation is higher since it could not be cooled. The PIN, APD and PMT have higher sensitivity, suitable for low dose rate and out-of-field dose monitoring. PMT's relative uncertainty remains under 1 % at the lowest dose rate achievable (50 μGy/s), suggesting optimal use for live dosimetry. Conclusion: A set of 6 photodetectors have been studied over a broad dose rate range at various energies. For dose rate above 3 mGy/s, the PIN diode is the most effective photodetector in term of performance/cost ratio. For lower dose rate, such as those seen in interventional radiology, PMTs are the optimal choice. FQRNT Doctoral Research Scholarship.

  7. Performance of the Cylindrical Drift Chamber and the Inner Plastic Scintillator in the BGOegg experiment

    NASA Astrophysics Data System (ADS)

    Shibukawa, Takuya; Masumoto, Shinichi; Ozawa, Kyoichiro; Ohnishi, Hiroaki; Muramatsu, Norihito; Ishikawa, Takatsugu; Miyabe, Manabu; Tsuchikawa, Yusuke; Yamazaki, Ryuji; Matsumura, Yuji; Mizutani, Keigo; Hashimoto, Toshikazu; Hamano, Hirotomo; LEPS2/BGOegg Collaboration

    2014-09-01

    Properties of vector mesons, such as ω mesons, in nucleus are intensively measured to study interactions between mesons and nuclear medium. To study ω meson properties in nuclei, we search for the nuclear ω bound states in the LEPS2/BGOegg experiment at SPring-8. If a strongly bounded ω state exists and binding energy is measured, it gives a phenomenological information about interactions between ω meson and nuclei. ω meson is produced using the GeV γ rays at SPring-8/LEPS2 beamline. The ω bound state is searched from the missing mass measurements of forward going protons. ω meson production is identified by detecting γ and proton from ωN --> N* --> γp or ωN --> γΔ --> γπ p reaction. In the BGOegg experiment, charged particles are detected by Cylindrical Drift Chamber(CDC) and Inner Plastic Scintillators (IPS) around the target. CDC has 4 layers of stereo wires and each layer has 72 sense wires. IPS consists of 30 plastic scintillators. In this talk, the performance of CDC and IPS are described in detail. Properties of vector mesons, such as ω mesons, in nucleus are intensively measured to study interactions between mesons and nuclear medium. To study ω meson properties in nuclei, we search for the nuclear ω bound states in the LEPS2/BGOegg experiment at SPring-8. If a strongly bounded ω state exists and binding energy is measured, it gives a phenomenological information about interactions between ω meson and nuclei. ω meson is produced using the GeV γ rays at SPring-8/LEPS2 beamline. The ω bound state is searched from the missing mass measurements of forward going protons. ω meson production is identified by detecting γ and proton from ωN --> N* --> γp or ωN --> γΔ --> γπ p reaction. In the BGOegg experiment, charged particles are detected by Cylindrical Drift Chamber(CDC) and Inner Plastic Scintillators (IPS) around the target. CDC has 4 layers of stereo wires and each layer has 72 sense wires. IPS consists of 30 plastic

  8. Test and simulation of plastic scintillator strips readout by silicon photomultipliers

    NASA Astrophysics Data System (ADS)

    Balbi, G.; Boldini, M.; Cafaro, V.; Fabbri, F.; Giordano, V.; Montanari, A.; Rovelli, T.; Torromeo, G.; Tosi, N.

    2014-04-01

    We studied the light collection in plastic scintillator strips, optimized for the detection of Minimum Ionizing Particles (MIPs). The light is collected by Wave Length Shifter (WLS) fibers and detected by Silicon Photo Multipliers (SiPMs). The study is based on prototypes developed for the muon detector of SuperB experiment. In parallel to measurement made on various type of geometries, a complete simulation suite, based on FLUKA, was developed. The simulation parameters were tuned by comparison with real data. In this way, we were able to study the effects of geometries and assembling procedures on light collection and provide a useful simulation tool for the design of future prototypes.

  9. Optimization of a coincidence system using plastic scintillators in 4pi geometry.

    PubMed

    Dias, M S; Piuvezam-Filho, H; Koskinas, M F

    2008-01-01

    Improvements recently developed at the Nuclear Metrology Laboratory of IPEN-CNEN/SP in São Paulo were performed in order to increase the detector efficiency of a 4pibeta-gamma coincidence primary system using plastic scintillators in 4pi geometry. Measurements were undertaken and compared to the original system and Monte Carlo simulations of the extrapolation curves were calculated for this new system and compared to experimental results. For this purpose, the code Penelope was applied for calculating response functions for each detector and the code Esquema, developed at LMN, was used for simulating the decay scheme processes.

  10. A large dynamic range readout design for the plastic scintillator detector of DAMPE

    NASA Astrophysics Data System (ADS)

    Zhou, Yong; Sun, Zhiyu; Yu, Yuhong; Zhang, Yongjie; Fang, Fang; Chen, Junling; Hu, Bitao

    2016-08-01

    A large dynamic range is required by the Plastic Scintillator Detector (PSD) of DArk Matter Particle Explorer (DAMPE) to detect particles from electron to heavy ions with Z ≤ 20. To expand the dynamic range, the readout design based on the double-dynodes signal extraction from the photomultiplier tube has been proposed and adopted by PSD. To verify this design, a prototype detector module has been constructed and tested with cosmic ray and relativistic ion beam. The results match with the estimation and the readout unit could easily cover the required dynamic range of about 4 orders of magnitude.

  11. Measurement of tritium with plastic scintillator surface improvement with plasma treatment

    SciTech Connect

    Yoshihara, Y.; Furuta, E.; Ohyama, R.I.; Yokota, S.; Kato, Y.; Yoshimura, T.; Ogiwara, K.

    2015-03-15

    Tritium is usually measured by using a liquid scintillation counter. However, liquid scintillator used for measurement will become radioactive waste fluid. To solve this issue, we have developed a method of measuring tritium samples with plasma-treated plastic scintillator (PS)sheets (Plasma method). The radioactive sample is held between 2 PS sheets and the whole is enclosed in a a low-potassium glass vial. With the Plasma method of 2-min plasma treatment, we have obtained measurement efficiency of 48 ± 2 % for 2 min measurement of tritium except for tritiated water. The plasma treatment makes the PS surface rough and hydrophilic which contributes to improve the contact between tritium and PS. On the other hand, it needed almost 6 hours to obtain constant measurement efficiency. The reason was that the dry-up handling in the vial needed longer time to vaporize H{sub 2}O molecules than in the air. We tried putting silica gel beads into vials to remove H{sub 2}O molecules from PS sheet surface quickly. The silica gel beads worked well and we got constant measurement efficiency within 1-3 hours. Also, we tried using other kinds of PS treated with plasma to obtain higher measurement efficiencies of tritium samples.

  12. Effects of Temperature and X-rays on Plastic Scintillating Fiber and Infrared Optical Fiber.

    PubMed

    Lee, Bongsoo; Shin, Sang Hun; Jang, Kyoung Won; Yoo, Wook Jae

    2015-01-01

    In this study, we have studied the effects of temperature and X-ray energy variations on the light output signals from two different fiber-optic sensors, a fiber-optic dosimeter (FOD) based on a BCF-12 as a plastic scintillating fiber (PSF) and a fiber-optic thermometer (FOT) using a silver halide optical fiber as an infrared optical fiber (IR fiber). During X-ray beam irradiation, the scintillating light and IR signals were measured simultaneously using a dosimeter probe of the FOD and a thermometer probe of the FOT. The probes were placed in a beaker with water on the center of a hotplate, under variation of the tube potential of a digital radiography system or the temperature of the water in the beaker. From the experimental results, in the case of the PSF, the scintillator light output at the given tube potential decreased as the temperature increased in the temperature range from 25 to 60 °C. We demonstrated that commonly used BCF-12 has a significant temperature dependence of -0.263 ± 0.028%/°C in the clinical temperature range. Next, in the case of the IR fiber, the intensity of the IR signal was almost uniform at each temperature regardless of the tube potential range from 50 to 150 kVp. Therefore, we also demonstrated that the X-ray beam with an energy range used in diagnostic radiology does not affect the IR signals transmitted via a silver halide optical fiber.

  13. Study of a detector system for high-energy astrophysical objects using a combination of plastic scintillator and MPPC

    NASA Astrophysics Data System (ADS)

    Nakaoka, Tatsuya; Mizuno, Tsunefumi; Takahashi, Hiromitsu; Fukazawa, Yasushi

    2016-09-01

    We have investigated a hard X-ray detector system using a combination of a plastic scintillator and multi-pixel photon counters (MPPC). Photomultiplier tubes (PMTs) have typically been adopted to read scintillators because of their high gain and large photoelectric surface, and studies on PMT and scintillator systems are well advanced. However, PMTs have limitations; for example, they are relatively large in size, require high voltage to operate, and cannot be used in strong magnetic fields. On the other hand, MPPCs do not have such limitations and instead possess high quantum efficiency and a large compact size. Therefore, we have studied a detector system that combines an MPPC with a plastic scintillator. The system is primarily intended to be used for polarization measurements of high-energy astrophysical objects. We achieved an energy threshold of as low as ~5 keV while operating the detector at low temperature (-10 °C), reading the signal with short integration time (50 ns), and using a low-noise MPPC. We also confirmed that the light yield of our MPPC+plastic scintillator system is comparable to that obtained using a conventional PMT to read the scintillator signal. Herein, we report test results and future prospects.

  14. MA-NRBC: First successful attempt for neutron gamma discrimination in plastic scintillators

    SciTech Connect

    Normand, S.; Kondrasovs, V.; Corre, G.; Bourbotte, J. M.; Ferragut, A.

    2011-07-01

    In this paper, a new electronic hardware and algorithms enabling discrimination between neutron and gamma in plastic scintillators together with the first associated experimental results, are presented. This electronic platform is mainly based onto a quad 200 MHz ADCs. Using phase rotating, it is possible to sample the signal up to 800 MHz equivalent, with 8 bits precision. This sampling frequency allows a real time signal processing. Despite all previous work, we have shown during this study that it is possible to discriminate neutron from gamma in plastic scintillators even for low energy neutrons (less than 10 MeV). Two patents have been accepted and registered; the first deals with the intrinsic signal processing and the second with thermal stabilization methods of photomultiplier tubes. The system could be used up to 100 000 events per second (both gamma and neutron). This system is currently dedicated to homeland security devices; this is due to its response time (in the order of 1 up to 3 seconds). The next step is to implement the thermal stabilization algorithm in the FPGA and micro-controller to obtain a global system free from any trouble caused by the environment thermal variations. This aspect of the research is crucial for measurements in the field. The time response should also be improved to make it a reliable alternative to Helium-3 shortage for neutron detection at borders checkpoint. (authors)

  15. Analysis of (210)Pb in water samples with plastic scintillation resins.

    PubMed

    Lluch, E; Barrera, J; Tarancón, A; Bagán, H; García, J F

    2016-10-12

    (210)Pb is a radioactive lead isotope present in the environment as member of the (238)U decay chain. Since it is a relatively long-lived radionuclide (T1/2 = 22.2 years), its analysis is of interest in radiation protection and the geochronology of sediments and artwork. Here, we present a method for analysing (210)Pb using plastic scintillation resins (PSresins) packaged in solid-phase extraction columns (SPE cartridge). The advantages of this method are its selectivity, the low limit of detection, as well as reductions in the amount of time and reagents required for analysis and the quantity of waste generated. The PSresins used in this study were composed of a selective extractant (4',4″(5″)-Di-tert-butyldicyclohexano-18-crown-6 in 1-octanol) covering the surface of plastic scintillation microspheres. Once the amount of extractant (1:1/4) and medium of separation (2 M HNO3) were optimised, PSresins in SPE cartridges were calibrated with a standard solution of (210)Pb. (210)Pb could be fully separated from its daughters, (210)Bi and (210)Po, with a recovery value of 91(3)% and detection efficiency of 44(3)%. Three spiked water samples (one underground and two river water samples) were analysed in triplicates with deviations lower than 10%, demonstrating the validity of the PS resin method for (210)Pb analysis. PMID:27662757

  16. Pulse shape discrimination using EJ-299-33 plastic scintillator coupled with a Silicon Photomultiplier array

    NASA Astrophysics Data System (ADS)

    Liao, Can; Yang, Haori

    2015-07-01

    Recent developments in organic plastic scintillators capable of pulse shape discrimination (PSD) have gained much interest. Novel photon detectors, such as Silicon Photomultipliers (SiPMs), offer numerous advantages and can be used as an alternative to conventional photo multiplier tubes (PMTs) in many applications. In this work, we evaluate the PSD performance of the EJ-299-33 plastic scintillator coupled with a SiPM array. 2D PSD plots as well as the Figure of Merit (FOM) parameters are presented to demonstrate the PSD capability of EJ-299-33 using a SiPM as the light sensor. The best FOM of 0.76 was observed with a 1.0 MeVee (MeV-electron-equivalent) energy threshold, despite the high noise level of the SiPM array. A high-speed digital oscilloscope was used to acquire data, which was then processed offline in MATLAB. A performance comparison between two different PSD algorithms was carried out. The dependence of PSD quality on the sampling rate was also evaluated, stimulated by the interest to implement this setup for handheld applications where power consumption is crucial.

  17. Bis(pinacolato)diboron as an additive for the detection of thermal neutrons in plastic scintillators

    NASA Astrophysics Data System (ADS)

    Mahl, Adam; Yemam, Henok A.; Stuntz, John; Remedes, Tyler; Sellinger, Alan; Greife, Uwe

    2016-04-01

    A readily available and inexpensive boron compound was tested as an additive for the detection of thermal neutrons in plastic scintillators. Bis(pinacolato)diboron (B2Pin2) was determined to be a compatible boron source (8.51 wt% boron, 1.70 wt% 10B) in poly(vinyltoluene) based matrices. Plastic scintillator blends of 1-20 wt% 2,5-diphenyloxazole (PPO), 0.1 wt% 1,4-bis(5-phenyloxazol-2-yl) benzene (POPOP) and 1-15 wt% B2Pin2 were prepared that provided optical clarity, good mechanical properties, and the capability of thermal neutron detection. Independent of B2Pin2 concentration, strong 10B neutron capture signals around 90 keVee were observed at essentially constant light output. Increasing PPO concentration allowed for the use of pulse shape discrimination (PSD) in both fast and thermal neutron detection. High PPO concentrations appear to cause additional alpha quenching that affected the 10B neutron capture signal. Aging effects after storage in air for several months were observed, which led to degradation of performance and in some samples of mechanical stability.

  18. Measurements of response functions of EJ-299-33A plastic scintillator for fast neutrons

    NASA Astrophysics Data System (ADS)

    Hartman, J.; Barzilov, A.; Peters, E. E.; Yates, S. W.

    2015-12-01

    Monoenergetic neutron response functions were measured for an EJ-299-33A plastic scintillator. The 7-MV Van de Graaff accelerator at the University of Kentucky Accelerator Laboratory was used to produce proton and deuteron beams for reactions with gaseous tritium and deuterium targets, yielding monoenergetic neutrons by means of the 3H(p,n)3He, 2H(d,n)3He, and 3H(d,n)4He reactions. The neutron energy was selected by tuning the charged-particle's energy and using the angular dependence of the neutron emission. The resulting response functions were measured for 0.1-MeV steps in neutron energy from 0.1 MeV to 8.2 MeV and from 12.2 MeV to 20.2 MeV. Experimental data were processed using a procedure for digital pulse-shape discrimination, which allowed characterization of the response functions of the plastic scintillator to neutrons only. The response functions are intended for use in neutron spectrum unfolding methods.

  19. Nanostructured organosilicon luminophores and their application in highly efficient plastic scintillators

    NASA Astrophysics Data System (ADS)

    Ponomarenko, Sergei A.; Surin, Nikolay M.; Borshchev, Oleg V.; Luponosov, Yuriy N.; Akimov, Dmitry Y.; Alexandrov, Ivan S.; Burenkov, Alexander A.; Kovalenko, Alexey G.; Stekhanov, Viktor N.; Kleymyuk, Elena A.; Gritsenko, Oleg T.; Cherkaev, Georgiy V.; Kechek'yan, Alexander S.; Serenko, Olga A.; Muzafarov, Aziz M.

    2014-10-01

    Organic luminophores are widely used in various optoelectronic devices, which serve for photonics, nuclear and particle physics, quantum electronics, medical diagnostics and many other fields of science and technology. Improving their spectral-luminescent characteristics for particular technical requirements of the devices is a challenging task. Here we show a new concept to universal solution of this problem by creation of nanostructured organosilicon luminophores (NOLs), which are a particular type of dendritic molecular antennas. They combine the best properties of organic luminophores and inorganic quantum dots: high absorption cross-section, excellent photoluminescence quantum yield, fast luminescence decay time and good processability. A NOL consists of two types of covalently bonded via silicon atoms organic luminophores with efficient Förster energy transfer between them. Using NOLs in plastic scintillators, widely utilized for radiation detection and in elementary particles discoveries, led to a breakthrough in their efficiency, which combines both high light output and fast decay time. Moreover, for the first time plastic scintillators, which emit light in the desired wavelength region ranging from 370 to 700 nm, have been created. We anticipate further applications of NOLs as working elements of pulsed dye lasers in photonics, optoelectronics and as fluorescent labels in biology and medical diagnostics.

  20. Analysis of (210)Pb in water samples with plastic scintillation resins.

    PubMed

    Lluch, E; Barrera, J; Tarancón, A; Bagán, H; García, J F

    2016-10-12

    (210)Pb is a radioactive lead isotope present in the environment as member of the (238)U decay chain. Since it is a relatively long-lived radionuclide (T1/2 = 22.2 years), its analysis is of interest in radiation protection and the geochronology of sediments and artwork. Here, we present a method for analysing (210)Pb using plastic scintillation resins (PSresins) packaged in solid-phase extraction columns (SPE cartridge). The advantages of this method are its selectivity, the low limit of detection, as well as reductions in the amount of time and reagents required for analysis and the quantity of waste generated. The PSresins used in this study were composed of a selective extractant (4',4″(5″)-Di-tert-butyldicyclohexano-18-crown-6 in 1-octanol) covering the surface of plastic scintillation microspheres. Once the amount of extractant (1:1/4) and medium of separation (2 M HNO3) were optimised, PSresins in SPE cartridges were calibrated with a standard solution of (210)Pb. (210)Pb could be fully separated from its daughters, (210)Bi and (210)Po, with a recovery value of 91(3)% and detection efficiency of 44(3)%. Three spiked water samples (one underground and two river water samples) were analysed in triplicates with deviations lower than 10%, demonstrating the validity of the PS resin method for (210)Pb analysis.

  1. The customized groud test platforms for the plastic scintillator detector of DAMPE

    NASA Astrophysics Data System (ADS)

    Zhou, Yong; Sun, Zhiyu; Yu, Yuhong; Fang, Fang; Chen, Junling; Zhang, Yongjie

    2016-07-01

    The DArk Matter Particle Explorer (DAMPE) is a high-precision satellite-borne spectrometer aiming for dark matter search, understanding of the origin and propagation of cosmic rays and gamma-ray astronomy. The Plastic Scintillator Detector (PSD) is a key sub-detector of DAMPE, which provides the function of e/γ discrimination and charge measurement from proton to calcium. It consists of 82 plastic scintillator bars with the dimension of 884mm×28mm×10mm, each readout by two photomultiplier tubes (PMT) at both ends. To ensure the quality and achieve the best performance, various ground tests have been carried out during the construction phase of PSD both on the module and system scale. Customized test platforms are designed and constructed to facilitate these works which includes a test bench for batch PMT characterization and qualification with the capacity of 25 tubes, a test bench for batch scintillator bar characterization with the capacity of 24 bars, and an integrated platform which emulates the vacuum condition in space and provides accurate tracking of the incident cosmic ray particle for precise calibration of the PSD detector as a whole. A dedicated analysis software based on ROOT library has also been developed for PSD ground test, which can process both the engineering and science data, and combines decoding, analysis and data visualization into a single framework. These facilities constitute a complete test suite for PSD development and are applied successfully in the construction of both the Engineering Qualified Model and the Flight Model of PSD.

  2. SU-E-T-553: Characterization of Plastic Scintillator Detectors for Radiation Therapy

    SciTech Connect

    Liu, H; Lin, H; Darafsheh, A; Finlay, J; Both, S; Zhu, T

    2014-06-01

    Purpose: To characterize basic performance of plastic scintillator detectors (PSD) designed for dosimetry of radiation therapy. Methods: The Exradin W1 Scintillator is a plastic scintillating fiber-based detector designed for highly accurate measurement of small radiotherapy fields used in patient plan verification and machine commissioning and QA procedures. The Cerenkov emissions were corrected using spectral separation. The optical signal was converted to electronic signal with a photodiode. We measured its dosimetry performance, including percentage depth dose, output factor, dose and dose rate linear response. We compared the dosimetry results with reference ion chamber measurements. Results: The dosimetry results of PSD agree well with reference ion chamber measurements. For percentage depth dose, the differences between PSD and ion chamber results are on average 1.7±1.1% and 0.8±0.8% with a maximum of 3.5% and 2.7% for 6MV and 15MV beams, respectively. For the output factors, PSD measurements are within 2% from ion chamber results. The dose linear response is within 1% when dose is larger than 20 MU for both 6 MV and 15 MV. The dose rate linear response is within 1% for the entire dose rate used (100 MU/min to 600MU/min). Conclusions: The current design of PSD is feasible for the dosimtry measurement in radiation therapy. This combination of PSD and photodiode system could be extended to multichannel array detection of dose distribution. It might as well be used as range verification in proton therapy. The work is partially supported by: DOD (W81XWH-09-2-0174) and American Cancer Society (IRG-78-002-28)

  3. A systematic characterization of the low-energy photon response of plastic scintillation detectors

    NASA Astrophysics Data System (ADS)

    Boivin, Jonathan; Beddar, Sam; Bonde, Chris; Schmidt, Daniel; Culberson, Wesley; Guillemette, Maxime; Beaulieu, Luc

    2016-08-01

    To characterize the low energy behavior of scintillating materials used in plastic scintillation detectors (PSDs), 3 PSDs were developed using polystyrene-based scintillating materials emitting in different wavelengths. These detectors were exposed to National Institute of Standards and Technology (NIST)-matched low-energy beams ranging from 20 kVp to 250 kVp, and to 137Cs and 60Co beams. The dose in polystyrene was compared to the dose in air measured by NIST-calibrated ionization chambers at the same location. Analysis of every beam quality spectrum was used to extract the beam parameters and the effective mass energy-absorption coefficient. Monte Carlo simulations were also performed to calculate the energy absorbed in the scintillators’ volume. The scintillators’ expected response was then compared to the experimental measurements and an energy-dependent correction factor was identified to account for low-energy quenching in the scintillators. The empirical Birks model was then compared to these values to verify its validity for low-energy electrons. The clear optical fiber response was below 0.2% of the scintillator’s light for x-ray beams, indicating that a negligible amount of fluorescence contamination was produced. However, for higher-energy beams (137Cs and 60Co), the scintillators’ response was corrected for the Cerenkov stem effect. The scintillators’ response increased by a factor of approximately 4 from a 20 kVp to a 60Co beam. The decrease in sensitivity from ionization quenching reached a local minimum of about 11%+/- 1% between 40 keV and 60 keV x-ray beam mean energy, but dropped by 20% for very low-energy (13 keV) beams. The Birks model may be used to fit the experimental data, but it must take into account the energy dependence of the kB quenching parameter. A detailed comprehension of intrinsic scintillator response is essential for proper calibration of PSD dosimeters for radiology.

  4. Dosimetric performance and array assessment of plastic scintillation detectors for stereotactic radiosurgery quality assurance

    SciTech Connect

    Gagnon, Jean-Christophe; Theriault, Dany; Guillot, Mathieu; Archambault, Louis; Beddar, Sam; Gingras, Luc; Beaulieu, Luc

    2012-01-15

    Purpose: To compare the performance of plastic scintillation detectors (PSD) for quality assurance (QA) in stereotactic radiosurgery conditions to a microion-chamber (IC), Gafchromic EBT2 films, 60 008 shielded photon diode (SD) and unshielded diodes (UD), and assess a new 2D crosshair array prototype adapted to small field dosimetry. Methods: The PSD consists of a 1 mm diameter by 1 mm long scintillating fiber (BCF-60, Saint-Gobain, Inc.) coupled to a polymethyl-methacrylate optical fiber (Eska premier, Mitsubishi Rayon Co., Ltd., Tokyo, Japan). Output factors (S{sub c,p}) for apertures used in radiosurgery ranging from 4 to 40 mm in diameter have been measured. The PSD crosshair array (PSDCA) is a water equivalent device made up of 49 PSDs contained in a 1.63 cm radius area. Dose profiles measurements were taken for radiosurgery fields using the PSDCA and were compared to other dosimeters. Moreover, a typical stereotactic radiosurgery treatment using four noncoplanar arcs was delivered on a spherical phantom in which UD, IC, or PSD was placed. Using the Xknife planning system (Integra Radionics Burlington, MA), 15 Gy was prescribed at the isocenter, where each detector was positioned. Results: Output Factors measured by the PSD have a mean difference of 1.3% with Gafchromic EBT2 when normalized to a 10 x 10 cm{sup 2} field, and 1.0% when compared with UD measurements normalized to the 35 mm diameter cone. Dose profiles taken with the PSD crosshair array agreed with other single detectors dose profiles in spite of the presence of the 49 PSDs. Gamma values comparing 1D dose profiles obtained with PSD crosshair array with Gafchromic EBT2 and UD measured profiles shows 98.3% and 100.0%, respectively, of detector passing the gamma acceptance criteria of 0.3 mm and 2%. The dose measured by the PSD for a complete stereotactic radiosurgery treatment is comparable to the planned dose corrected for its SD-based S{sub c,p} within 1.4% and 0.7% for 5 and 35 mm diameter cone

  5. Pulse-shape discrimination of the new plastic scintillators in neutron-gamma mixed field using fast digitizer card

    NASA Astrophysics Data System (ADS)

    Jančář, A.; Kopecký, Z.; Dressler, J.; Veškrna, M.; Matěj, Z.; Granja, C.; Solar, M.

    2015-11-01

    Recently invented plastic scintillator EJ-299-33 enables pulse-shape discrimination (PSD) and thus measurement of neutron and photon spectra in mixed fields. In this work we compare the PSD properties of EJ-299-33 plastic and the well-known NE-213 liquid scintillator in monoenergetic neutron fields generated by the Van de Graaff accelerator using the 3H(d, n)4He reaction. Pulses from the scintillators are processed by a newly developed digital measuring system employing the fast digitizer card. This card contains two AD converters connected to the measuring computer via 10 Gbps optical ethernet. The converters operate with a resolution of 12 bits and have two differential inputs with a sampling frequency 1 GHz. The resulting digital channels with different gains are merged into one composite channel with a higher digital resolution in a wide dynamic range of energies. Neutron signals are fully discriminated from gamma signals. Results are presented.

  6. Effects of Temperature and X-rays on Plastic Scintillating Fiber and Infrared Optical Fiber

    PubMed Central

    Lee, Bongsoo; Shin, Sang Hun; Jang, Kyoung Won; Yoo, Wook Jae

    2015-01-01

    In this study, we have studied the effects of temperature and X-ray energy variations on the light output signals from two different fiber-optic sensors, a fiber-optic dosimeter (FOD) based on a BCF-12 as a plastic scintillating fiber (PSF) and a fiber-optic thermometer (FOT) using a silver halide optical fiber as an infrared optical fiber (IR fiber). During X-ray beam irradiation, the scintillating light and IR signals were measured simultaneously using a dosimeter probe of the FOD and a thermometer probe of the FOT. The probes were placed in a beaker with water on the center of a hotplate, under variation of the tube potential of a digital radiography system or the temperature of the water in the beaker. From the experimental results, in the case of the PSF, the scintillator light output at the given tube potential decreased as the temperature increased in the temperature range from 25 to 60 °C. We demonstrated that commonly used BCF-12 has a significant temperature dependence of −0.263 ± 0.028%/°C in the clinical temperature range. Next, in the case of the IR fiber, the intensity of the IR signal was almost uniform at each temperature regardless of the tube potential range from 50 to 150 kVp. Therefore, we also demonstrated that the X-ray beam with an energy range used in diagnostic radiology does not affect the IR signals transmitted via a silver halide optical fiber. PMID:25970257

  7. Passively scattered proton beam entrance dosimetry with a plastic scintillation detector

    PubMed Central

    Wootton, Landon; Holmes, Charles; Sahoo, Narayan; Beddar, Sam

    2015-01-01

    We tested the feasibility of using plastic scintillation detectors (PSDs) for proton entrance dosimetry. A PSD built with BCF-12 scintillating fiber was used to measure the absolute entrance dose of a passively scattered proton beam for energies ranging from 140 MeV to 250 MeV, and for a range of spread out Bragg peak (SOBP) widths at 2 energies, to quantify the effect of ionization quenching on the response of the detector and to determine the necessity of Cerenkov radiation correction in proton beams. The overall accuracy and precision of the PSD was evaluated by measuring lateral beam profiles and comparing the results with profiles measured using film. The PSD under-responded owing to ionization quenching, exhibiting approximately a 7% loss of signal at the highest energy studied (250 MeV) and a 10% loss of signal at the lowest energy studied (140 MeV). For a given nominal energy, varying the SOBP width did not significantly alter the response of the PSD. Cerenkov radiation contributed negligibly to the PSD signal and can be safely ignored without introducing more than 1% error in the measured dose. Profiles measured with the PSD and film agreed to within the uncertainty of the detector, demonstrating good relative accuracy. Although correction factors were necessary to account for ionization quenching, the magnitude of the correction varied minimally over a broad range of energies; PSDs therefore represent a practical detector for proton entrance dosimetry. PMID:25591037

  8. Passively scattered proton beam entrance dosimetry with a plastic scintillation detector

    NASA Astrophysics Data System (ADS)

    Wootton, Landon; Holmes, Charles; Sahoo, Narayan; Beddar, Sam

    2015-02-01

    We tested the feasibility of using plastic scintillation detectors (PSDs) for proton entrance dosimetry. A PSD built with BCF-12 scintillating fiber was used to measure the absolute entrance dose of a passively scattered proton beam for energies ranging from 140 to 250 MeV, and for a range of spread out Bragg peak (SOBP) widths at two energies, to quantify the effect of ionization quenching on the response of the detector and to determine the necessity of Cerenkov radiation correction in proton beams. The overall accuracy and precision of the PSD was evaluated by measuring lateral beam profiles and comparing the results with profiles measured using film. The PSD under-responded owing to ionization quenching, exhibiting approximately a 7% loss of signal at the highest energy studied (250 MeV) and a 10% loss of signal at the lowest energy studied (140 MeV). For a given nominal energy, varying the SOBP width did not significantly alter the response of the PSD. Cerenkov radiation contributed negligibly to the PSD signal and can be safely ignored without introducing more than 1% error in the measured dose. Profiles measured with the PSD and film agreed to within the uncertainty of the detector, demonstrating good relative accuracy. Although correction factors were necessary to account for ionization quenching, the magnitude of the correction varied minimally over a broad range of energies; PSDs therefore represent a practical detector for proton entrance dosimetry.

  9. A new anti-neutrino detection technique based on positronium tagging with plastic scintillators

    NASA Astrophysics Data System (ADS)

    Consolati, G.; Franco, D.; Jollet, C.; Meregaglia, A.; Minotti, A.; Perasso, S.; Tonazzo, A.

    2015-09-01

    The main signature for anti-neutrino detection in reactor and geo-neutrino experiments based on scintillators is provided by the space-time coincidence of positron and neutron produced in the Inverse Beta Decay reaction. Such a signature strongly suppresses backgrounds and allows for measurements performed underground with a relatively high signal-to-background ratio. In an aboveground environment, however, the twofold coincidence technique is not sufficient to efficiently reject the high background rate induced by cosmogenic events. Enhancing the positron-neutron twofold coincidence efficiency may pave the way to future aboveground detectors for reactor monitoring. We propose a new detection scheme based on a threefold coincidence, among the positron ionization, the ortho-positronium (o-Ps) decay, and the neutron capture, in a sandwich detector with alternated layers of plastic scintillator and aerogel powder. We present the results of a set of dedicated measurements on the achievable light yield and on the o-Ps formation and lifetime. The efficiencies for signal detection and background rejection of a preliminary detector design are also discussed.

  10. Radiation hardness of plastic scintillators for the Tile Calorimeter of the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Jivan, H.; Sideras-Haddad, E.; Erasmus, R.; Liao, S.; Madhuku, M.; Peters, G.; Sekonya, K.; Solvyanov, O.

    2015-10-01

    The radiation damage in polyvinyl toluene based plastic scintillator EJ200 obtained from ELJEN technology was investigated. This forms part of a comparative study conducted to aid in the upgrade of the Tile Calorimeter of the ATLAS detector during which the Gap scintillators will be replaced. Samples subjected to 6 MeV proton irradiation using the tandem accelerator of iThemba LABS, were irradiated with doses of approximately 0.8 MGy, 8 MGy, 25 MGy and 80 MGy. The optical properties were investigated using transmission spectroscopy and light yield analysis whilst structural damage was assessed using Raman spectroscopy. Findings indicate that for the dose of 0.8 MGy, no structural damage occurs and light loss can be attributed to a breakdown in the light transfer between base and fluor dopants. For doses of 8 MGy to 80 MGy, structural damage leads to possible hydrogen loss in the benzene ring of the PVT base which forms free radicals. This results in an additional absorptive component causing increased transmission loss and light yield loss with increasing dose.

  11. Radiation hardness of plastic scintillators for the Tile Calorimeter of the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Jivan, H.; Mellado, B.; Sideras-Haddad, E.; Erasmus, R.; Liao, S.; Madhuku, M.; Peters, G.; Solvyanov, O.

    2015-06-01

    The radiation damage in polyvinyl toluene based plastic scintillator EJ200 obtained from ELJEN technology was investigated. This forms part of a comparative study conducted to aid in the upgrade of the Tile Calorimeter of the ATLAS detector during which the Gap scintillators will be replaced. Samples subjected to 6 MeV proton irradiation using the tandem accelerator of iThemba LABS, were irradiated with doses of approximately 0.8 MGy, 8 MGy, 25 MGy and 80 MGy. The optical properties were investigated using transmission spectroscopy whilst structural damage was assessed using Raman spectroscopy. Findings indicate that for the dose of 0.8 MGy, no structural damage occurs but a breakdown in the light transfer between base and fluor dopants is observed. For doses of 8 MGy to 80 MGy, structural damage leads to hydrogen loss in the benzene ring of the PVT base which forms free radicals. This results in an additional absorptive component causing increased transmission loss as dose is increased.

  12. Optimizing concentration of shifter additive for plastic scintillators of different size

    NASA Astrophysics Data System (ADS)

    Adadurov, A. F.; Zhmurin, P. N.; Lebedev, V. N.; Titskaya, V. D.

    2009-02-01

    This paper concerns the influence of wavelength shifting (secondary) luminescent additive (LA 2) on the light yield of polystyrene-based plastic scintillator (PS) taking self-absorption into account. Calculations of light yield dependence on concentration of 1.4-bis(2-(5-phenyloxazolyl)-benzene (POPOP) as LA 2 were made for various path lengths of photons in PS. It is shown that there is an optimal POPOP concentration ( Copt), which provides a maximum light yield for a given path length. This optimal concentration is determined by the competition of luminescence and self-reflection processes. Copt values were calculated for PS of different dimensions. For small PS, Copt≈0.02%, which agree with a common (standard) value of POPOP concentration. For higher PS dimensions, the optimal POPOP concentration is decreased (to Copt≈0.006% for 320×30×2 cm sample), reducing the light yield from PS by almost 35%.

  13. Development and characterization of a tissue equivalent plastic scintillator based dosimetry system.

    PubMed

    Petric, M P; Robar, J L; Clark, B G

    2006-01-01

    High precision techniques in radiation therapy, such as intensity modulated radiation therapy, offer the potential for improved target coverage and increased normal tissue sparing compared with conformal radiotherapy. The complex fluence maps used in many of these techniques, however, often lead to more challenging quality assurance with dose verification being labor-intensive and time consuming. A prototype dose verification system has been developed using a tissue equivalent plastic scintillator that provides easy-to-acquire, rapid, digital dose measurements in a plane perpendicular to the beam. The system consists of a water-filled Lucite phantom with a scintillator screen built into the top surface. The phantom contains a silver coated plastic mirror to reflect scintillation light towards a viewing window where it is captured using a charge coupled device camera and a personal computer. Optical photon spread is removed using a microlouvre optical collimator and by deconvolving a glare kernel from the raw images. A characterization of the system was performed that included measurements of linear output response, dose rate dependence, spatial linearity, effective pixel size, signal uniformity and both short- and long-term reproducibility. The average pixel intensity for static, regular shaped fields between 3 cm X 3 cm and 12 cm x 12 cm imaged with the system was found to be linear in the dose delivered with linear regression analysis yielding a correlation coefficient r2 > 0.99. Effective pixel size was determined to be 0.53 mm/pixel. The system was found to have a signal uniformity of 5.6% and a long-term reproducibility/stability of 1.7% over a 6 month period. The system's ability to verify a dynamic treatment field was evaluated using 60 degrees dynamic wedged fields and comparing the results to two-dimensional film dosimetry. Results indicate agreement with two-dimensional film dosimetry distributions within 8% inside the field edges. With further

  14. Time correlated measurements using plastic scintillators with neutron-photon pulse shape discrimination

    NASA Astrophysics Data System (ADS)

    Richardson, Norman E., IV

    nuclear and radiological material. Moreover, the production of 3He isotope as a byproduct of security programs was drastically decreased. This isotope shortage coupled with the disadvantages of relying on a detector that requires neutron moderation before the detection of fission neutrons, poses a significant challenge in supporting the existing detection systems and the development of future technologies. To address this problem, a reliable and accurate alternative technology to detect neutrons emitted in fissions must be developed. One such alternative technology that shows promise in this application is the use of scintillators based on solid state materials (plastics) which are sensitive to fast neutrons. However, plastic scintillators are also sensitive to photons. Hence, it is necessary to separate the neutron signals from the photon signals, using the pulse shape discrimination (PSD) analysis. The PSD is based on the comparison of the pulse shapes of digitized signal waveforms. This approach allows for the measurement of fast neutrons without the necessity of their moderation. Because the fission spectrum neutrons are mainly fast, methods employing fast neutron detection are applicable for the assay of fissile materials. In addition, the average time of scintillation of the plastic medium is much shorter than those of the gaseous counters, thus allowing scintillation detectors to be used in high count rate environments. Furthermore, the temporal information of the fast neutron detection using multiple sensors enables the time correlation analysis of the fission neutron multiplicity. The study of time correlation measurements of fast neutrons using the array of plastic scintillators is the basis of this work. The array of four plastic scintillator detectors equipped with the digital data acquisition and analysis system was developed. The digital PSD analysis of detector signals "on-the-fly" was implemented for the array. The time coincidence measurement technique

  15. A feasibility study of ortho-positronium decays measurement with the J-PET scanner based on plastic scintillators

    NASA Astrophysics Data System (ADS)

    Kamińska, D.; Gajos, A.; Czerwiński, E.; Alfs, D.; Bednarski, T.; Białas, P.; Curceanu, C.; Dulski, K.; Głowacz, B.; Gupta-Sharma, N.; Gorgol, M.; Hiesmayr, B. C.; Jasińska, B.; Korcyl, G.; Kowalski, P.; Krzemień, W.; Krawczyk, N.; Kubicz, E.; Mohammed, M.; Niedźwiecki, Sz.; Pawlik-Niedźwiecka, M.; Raczyński, L.; Rudy, Z.; Silarski, M.; Wieczorek, A.; Wiślicki, W.; Zgardzińska, B.; Zieliński, M.; Moskal, P.

    2016-08-01

    We present a study of the application of the Jagiellonian positron emission tomograph (J-PET) for the registration of gamma quanta from decays of ortho-positronium (o-Ps). The J-PET is the first positron emission tomography scanner based on organic scintillators in contrast to all current PET scanners based on inorganic crystals. Monte Carlo simulations show that the J-PET as an axially symmetric and high acceptance scanner can be used as a multi-purpose detector well suited to pursue research including e.g. tests of discrete symmetries in decays of ortho-positronium in addition to the medical imaging. The gamma quanta originating from o-Ps decay interact in the plastic scintillators predominantly via the Compton effect, making the direct measurement of their energy impossible. Nevertheless, it is shown in this paper that the J-PET scanner will enable studies of the { o-Ps }→ 3γ decays with angular and energy resolution equal to σ (θ ) ≈ {0.4°} and σ (E) ≈ 4.1 {keV}, respectively. An order of magnitude shorter decay time of signals from plastic scintillators with respect to the inorganic crystals results not only in better timing properties crucial for the reduction of physical and instrumental background, but also suppresses significantly the pile-ups, thus enabling compensation of the lower efficiency of the plastic scintillators by performing measurements with higher positron source activities.

  16. Monte Carlo code G3sim for simulation of plastic scintillator detectors with wavelength shifter fiber readout

    NASA Astrophysics Data System (ADS)

    Mohanty, P. K.; Dugad, S. R.; Gupta, S. K.

    2012-04-01

    A detailed description of a compact Monte Carlo simulation code "G3sim" for studying the performance of a plastic scintillator detector with wavelength shifter (WLS) fiber readout is presented. G3sim was developed for optimizing the design of new scintillator detectors used in the GRAPES-3 extensive air shower experiment. Propagation of the blue photons produced by the passage of relativistic charged particles in the scintillator is treated by incorporating the absorption, total internal, and diffuse reflections. Capture of blue photons by the WLS fibers and subsequent re-emission of longer wavelength green photons is appropriately treated. The trapping and propagation of green photons inside the WLS fiber is treated using the laws of optics for meridional and skew rays. Propagation time of each photon is taken into account for the generation of the electrical signal at the photomultiplier. A comparison of the results from G3sim with the performance of a prototype scintillator detector showed an excellent agreement between the simulated and measured properties. The simulation results can be parametrized in terms of exponential functions providing a deeper insight into the functioning of these versatile detectors. G3sim can be used to aid the design and optimize the performance of scintillator detectors prior to actual fabrication that may result in a considerable saving of time, labor, and money spent.

  17. A new plastic scintillation resin for single-step separation, concentration and measurement of technetium-99.

    PubMed

    Barrera, J; Tarancón, A; Bagán, H; García, J F

    2016-09-14

    Technetium is a synthetic element with no stable isotopes, produced as waste in nuclear power plants and in cyclotrons used for nuclear medicine. The element has high mobility, in the form of TcO4(-); its determination is therefore important for environmental protection. Technetium is found in low concentrations and therefore common methods for its analysis include long treatments in several steps and require large amounts of reagents for its purification and preconcentration. Plastic scintillation resins (PSresin) are novel materials used to separate, preconcentrate and measure radionuclides in a single step. The objective of this study is to prepare and characterise a PSresin for the preconcentration and measurement of (99)Tc. The study first evaluates the reproducibility of the production of PSresins between batches and over time; showing good reproducibility and storage stability. Next, we studied the effect of some common non-radioactive interferences, showing small influences on measurement, and radioactive interferences ((36)Cl and (238)U/(234)U). (36)Cl can be removed by a simple treatment with 0.5 M HCl and (238)U/(234)U can be removed from the column by cleaning with a mixture of 0.1 M HNO3 and 0.1 M HF. In the latter case, a slight change in the morphology of the PSresin caused an increase in detection efficiency. Finally, the PSresin was applied to the measurement of real spiked samples (sea water and urine) with deviations lower than 10% in all cases.

  18. Robustness of plastic scintillation microspheres in the continuous measurement of different river waters.

    PubMed

    Tarancón, A; Novella, O; Batlle, M; Pujadas, M; Cros, J; García, J F

    2016-08-01

    Plastic scintillation microspheres (PSm) represent one of the most promising options for monitoring alpha and beta radioactivity in river water. For that reason, a study of the stability of PSm packed into a cell against the continuous flow of river water with different degrees of turbidity was performed over a period of 100h. The results showed that the volume of the cell became stable after 15h of pumping and continued to be stable throughout the 100h of the experiment. During this period of time, the detection efficiency of the PSm, in terms of efficiency*volume, presented mean values of 0.75(3)% for (3)H and 272(11)% for (90)Sr/(90)Y. No dependence on flow time or river water type was observed. The background was also constant for 100h and for the different water types, although (222)Rn should be removed from the water beforehand to prevent its accumulation in the PSm. Since PSm did not present any degradation throughout the whole experiment, PSm can undoubtedly be used for monitoring radioactivity with low reagent consumption, low waste generation and low maintenance costs. PMID:27235888

  19. Robustness of plastic scintillation microspheres in the continuous measurement of different river waters.

    PubMed

    Tarancón, A; Novella, O; Batlle, M; Pujadas, M; Cros, J; García, J F

    2016-08-01

    Plastic scintillation microspheres (PSm) represent one of the most promising options for monitoring alpha and beta radioactivity in river water. For that reason, a study of the stability of PSm packed into a cell against the continuous flow of river water with different degrees of turbidity was performed over a period of 100h. The results showed that the volume of the cell became stable after 15h of pumping and continued to be stable throughout the 100h of the experiment. During this period of time, the detection efficiency of the PSm, in terms of efficiency*volume, presented mean values of 0.75(3)% for (3)H and 272(11)% for (90)Sr/(90)Y. No dependence on flow time or river water type was observed. The background was also constant for 100h and for the different water types, although (222)Rn should be removed from the water beforehand to prevent its accumulation in the PSm. Since PSm did not present any degradation throughout the whole experiment, PSm can undoubtedly be used for monitoring radioactivity with low reagent consumption, low waste generation and low maintenance costs.

  20. Neutron generator burst timing measured using a pulse shape discrimination plastic scintillator with silicon photomultiplier readout

    NASA Astrophysics Data System (ADS)

    Preston, R. M.; Eberhardt, J. E.; Tickner, J. R.

    2013-12-01

    An EJ-299-34 plastic scintillator with silicon photomultiplier (SiPM) readout was used to measure the fast neutron output of a pulsed Thermo-Fisher A-325 Deuterium-Tritium sealed tube neutron generator (STNG). The SiPM signals were handled by a prototype digital pulse processing system, based on a free-running analogue to digital converter feeding a digital signal processor (DSP). Pulse shape discrimination was used to distinguish between detected fast-neutrons and gammas. Pulse detection, timing, energy and shape were all processed by the DSP in real-time. The time-dependency of the neutron output of the STNG was measured for various pulsing schemes. The switch-on characteristics of the tube strongly depended on the operating settings, with the delay between pulse turn-on and the production of neutrons ranging between 13 μs to 74 μs for the tested pulse rates and duty cycles. This work will facilitate the optimization and modeling of apparatus that use the neutron generator's pulsing abilities.

  1. Compressive sensing of signals generated in plastic scintillators in a novel J-PET instrument

    NASA Astrophysics Data System (ADS)

    Raczyński, L.; Moskal, P.; Kowalski, P.; Wiślicki, W.; Bednarski, T.; Białas, P.; Czerwiński, E.; Gajos, A.; Kapłon, Ł.; Kochanowski, A.; Korcyl, G.; Kowal, J.; Kozik, T.; Krzemień, W.; Kubicz, E.; Niedźwiecki, Sz.; Pałka, M.; Rudy, Z.; Rundel, O.; Salabura, P.; Sharma, N. G.; Silarski, M.; Słomski, A.; Smyrski, J.; Strzelecki, A.; Wieczorek, A.; Zieliński, M.; Zoń, N.

    2015-06-01

    The J-PET scanner, which allows for single bed imaging of the whole human body, is currently under development at the Jagiellonian University. The discussed detector offers improvement of the Time of Flight (TOF) resolution due to the use of fast plastic scintillators and dedicated electronics allowing for sampling in the voltage domain of signals with durations of few nanoseconds. In this paper we show that recovery of the whole signal, based on only a few samples, is possible. In order to do that, we incorporate the training signals into the Tikhonov regularization framework and we perform the Principal Component Analysis decomposition, which is well known for its compaction properties. The method yields a simple closed form analytical solution that does not require iterative processing. Moreover, from the Bayes theory the properties of regularized solution, especially its covariance matrix, may be easily derived. This is the key to introduce and prove the formula for calculations of the signal recovery error. In this paper we show that an average recovery error is approximately inversely proportional to the number of acquired samples.

  2. Application of the CIEMAT-NIST method to plastic scintillation microspheres.

    PubMed

    Tarancón, A; Barrera, J; Santiago, L M; Bagán, H; García, J F

    2015-04-01

    An adaptation of the MICELLE2 code was used to apply the CIEMAT-NIST tracing method to the activity calculation for radioactive solutions of pure beta emitters of different energies using plastic scintillation microspheres (PSm) and (3)H as a tracing radionuclide. Particle quenching, very important in measurements with PSm, was computed with PENELOPE using geometries formed by a heterogeneous mixture of polystyrene microspheres and water. The results obtained with PENELOPE were adapted to be included in MICELLE2, which is capable of including the energy losses due to particle quenching in the computation of the detection efficiency. The activity calculation of (63)Ni, (14)C, (36)Cl and (90)Sr/(90)Y solutions was performed with deviations of 8.8%, 1.9%, 1.4% and 2.1%, respectively. Of the different parameters evaluated, those with the greatest impact on the activity calculation are, in order of importance, the energy of the radionuclide, the degree of quenching of the sample and the packing fraction of the geometry used in the computation.

  3. A new plastic scintillation resin for single-step separation, concentration and measurement of technetium-99.

    PubMed

    Barrera, J; Tarancón, A; Bagán, H; García, J F

    2016-09-14

    Technetium is a synthetic element with no stable isotopes, produced as waste in nuclear power plants and in cyclotrons used for nuclear medicine. The element has high mobility, in the form of TcO4(-); its determination is therefore important for environmental protection. Technetium is found in low concentrations and therefore common methods for its analysis include long treatments in several steps and require large amounts of reagents for its purification and preconcentration. Plastic scintillation resins (PSresin) are novel materials used to separate, preconcentrate and measure radionuclides in a single step. The objective of this study is to prepare and characterise a PSresin for the preconcentration and measurement of (99)Tc. The study first evaluates the reproducibility of the production of PSresins between batches and over time; showing good reproducibility and storage stability. Next, we studied the effect of some common non-radioactive interferences, showing small influences on measurement, and radioactive interferences ((36)Cl and (238)U/(234)U). (36)Cl can be removed by a simple treatment with 0.5 M HCl and (238)U/(234)U can be removed from the column by cleaning with a mixture of 0.1 M HNO3 and 0.1 M HF. In the latter case, a slight change in the morphology of the PSresin caused an increase in detection efficiency. Finally, the PSresin was applied to the measurement of real spiked samples (sea water and urine) with deviations lower than 10% in all cases. PMID:27566363

  4. Technical Note: Out-of-field dose measurement at near surface with plastic scintillator detector.

    PubMed

    Bourgouin, Alexandra; Varfalvy, Nicolas; Archambault, Louis

    2016-01-01

    Out-of-field dose depends on multiple factors, making peripheral dosimetry com-plex. Only a few dosimeters have the required features for measuring peripheral dose. Plastic scintillator dosimeters (PSDs) offer numerous dosimetric advantages as required for out-of-field dosimetry. The purpose of this study is to determine the potential of using PSD as a surface peripheral dosimeter. Measurements were performed with a parallel-plate ion chamber, a small volume ion chamber, and with a PSD. Lateral-dose measurements (LDM) at 0.5 cm depth and depth-dose curve (PDD) were made and compared to the dose calculation provided by a treatment planning system (TPS). This study shows that a PSD can measure a dose as low as 0.51 ± 0.17 cGy for photon beam and 0.58 ± 0.20 cGy for electron beam with a difference of 0.2 and 0.1 cGy compared to a parallel-plate ion chamber. This study demonstrates the potential of using PSD as an out-of-field dosimeter since measure-ments with PSD avoid averaging over a too-large depth, at 1 mm diameter, and can make precise measurement at very low dose. Also, electronic equilibrium is easier to reach with PSD due to its small sensitive volume and its water equivalence. PMID:27685131

  5. Comparative Gamma Spectroscopy with SrI2(Eu), GYGAG(Ce) and Bi-loaded Plastic Scintillators

    SciTech Connect

    Cherepy, N J

    2010-11-19

    We are developing new scintillator materials that offer potential for high resolution gamma ray spectroscopy at low cost. Single crystal SrI{sub 2}(Eu) offers {approx}3% resolution at 662 keV, in sizes of {approx}1 in{sup 3}. We have developed ceramics processing technology allowing us to achieve cubic inch scale transparent ceramic scintillators offering gamma spectroscopy performance superior to NaI(Tl). We fabricated a bismuth-loaded plastic scintillator that demonstrates energy resolution of {approx}8% at 662 keV in small sizes. Gamma ray spectroscopy can be used to identify the presence of weak radioactive sources within natural background. The ability to discriminate close-lying spectral lines is strongly dependent upon the energy resolution of the detector. In addition to excellent energy resolution, large volume detectors are needed to acquire sufficient events, for example, to identify a radioactive anomaly moving past a detector. We have employed a 'directed search' methodology for identifying potential scintillator materials candidates, resulting in the discovery of Europium-doped Strontium Iodide, SrI{sub 2}(Eu), Cerium-doped Gadolinium Garnet, GYGAG(Ce), and Bismuth-loaded Polymers. These scintillators possess very low self-radioactivity, offer energy resolution of 3-8% at 662 keV, and have potential to be grown cost-effectively to sizes similar to the most widely deployed gamma spectroscopy scintillator, Thallium-doped Sodium Iodide, NaI(Tl). In this study, gamma ray spectra of a variety of sources, were obtained employing SrI{sub 2}(Eu), GYGAG(Ce), Bi-loaded polymers, LaBr{sub 3}(Ce), and NaI(Tl). The effects of detector size, energy resolution, and background radioactivity (including self-radioactivity) on the ability to distinguish weak sources is quantified, based on a simple model, and qualitatively compared to laboratory data.

  6. Monte Carlo simulation of a novel water-equivalent electronic portal imaging device using plastic scintillating fibers

    SciTech Connect

    Teymurazyan, A.; Pang, G.

    2012-03-15

    Purpose: Most electronic portal imaging devices (EPIDs) developed so far use a thin Cu plate/phosphor screen to convert x-ray energies into light photons, while maintaining a high spatial resolution. This results in a low x-ray absorption and thus a low quantum efficiency (QE) of approximately 2-4% for megavoltage (MV) x-rays. A significant increase of QE is desirable for applications such as MV cone-beam computed tomography (MV-CBCT). Furthermore, the Cu plate/phosphor screen contains high atomic number (high-Z) materials, resulting in an undesirable over-response to low energy x-rays (due to photoelectric effect) as well as high energy x-rays (due to pair production) when used for dosimetric verification. Our goal is to develop a new MV x-ray detector that has a high QE and uses low-Z materials to overcome the obstacles faced by current MV x-ray imaging technologies. Methods: A new high QE and low-Z EPID is proposed. It consists of a matrix of plastic scintillating fibers embedded in a water-equivalent medium and coupled to an optically sensitive 2D active matrix flat panel imager (AMFPI) for image readout. It differs from the previous approach that uses segmented crystalline scintillators made of higher density and higher atomic number materials to detect MV x-rays. The plastic scintillating fibers are focused toward the x-ray source to avoid image blurring due to oblique incidence of off-axis x-rays. When MV x-rays interact with the scintillating fibers in the detector, scintillation light will be produced. The light photons produced in a fiber core and emitted within the acceptance angle of the fiber will be guided toward the AMFPI by total internal reflection. A Monte Carlo simulation has been used to investigate imaging and dosimetric characteristics of the proposed detector under irradiation of MV x-rays. Results: Properties, such as detection efficiency, modulation transfer function, detective quantum efficiency (DQE), energy dependence of detector

  7. Monte Carlo study of the energy and angular dependence of the response of plastic scintillation detectors in photon beams

    SciTech Connect

    Wang, Lilie L. W.; Klein, David; Beddar, A. Sam

    2010-10-15

    Purpose: By using Monte Carlo simulations, the authors investigated the energy and angular dependence of the response of plastic scintillation detectors (PSDs) in photon beams. Methods: Three PSDs were modeled in this study: A plastic scintillator (BC-400) and a scintillating fiber (BCF-12), both attached by a plastic-core optical fiber stem, and a plastic scintillator (BC-400) attached by an air-core optical fiber stem with a silica tube coated with silver. The authors then calculated, with low statistical uncertainty, the energy and angular dependences of the PSDs' responses in a water phantom. For energy dependence, the response of the detectors is calculated as the detector dose per unit water dose. The perturbation caused by the optical fiber stem connected to the PSD to guide the optical light to a photodetector was studied in simulations using different optical fiber materials. Results: For the energy dependence of the PSDs in photon beams, the PSDs with plastic-core fiber have excellent energy independence within about 0.5% at photon energies ranging from 300 keV (monoenergetic) to 18 MV (linac beam). The PSD with an air-core optical fiber with a silica tube also has good energy independence within 1% in the same photon energy range. For the angular dependence, the relative response of all the three modeled PSDs is within 2% for all the angles in a 6 MV photon beam. This is also true in a 300 keV monoenergetic photon beam for PSDs with plastic-core fiber. For the PSD with an air-core fiber with a silica tube in the 300 keV beam, the relative response varies within 1% for most of the angles, except in the case when the fiber stem is pointing right to the radiation source in which case the PSD may over-response by more than 10%. Conclusions: At {+-}1% level, no beam energy correction is necessary for the response of all three PSDs modeled in this study in the photon energy ranges from 200 keV (monoenergetic) to 18 MV (linac beam). The PSD would be even closer

  8. Monte Carlo study of the energy and angular dependence of the response of plastic scintillation detectors in photon beams

    PubMed Central

    Wang, Lilie L. W.; Klein, David; Beddar, A. Sam

    2010-01-01

    Purpose: By using Monte Carlo simulations, the authors investigated the energy and angular dependence of the response of plastic scintillation detectors (PSDs) in photon beams. Methods: Three PSDs were modeled in this study: A plastic scintillator (BC-400) and a scintillating fiber (BCF-12), both attached by a plastic-core optical fiber stem, and a plastic scintillator (BC-400) attached by an air-core optical fiber stem with a silica tube coated with silver. The authors then calculated, with low statistical uncertainty, the energy and angular dependences of the PSDs’ responses in a water phantom. For energy dependence, the response of the detectors is calculated as the detector dose per unit water dose. The perturbation caused by the optical fiber stem connected to the PSD to guide the optical light to a photodetector was studied in simulations using different optical fiber materials. Results: For the energy dependence of the PSDs in photon beams, the PSDs with plastic-core fiber have excellent energy independence within about 0.5% at photon energies ranging from 300 keV (monoenergetic) to 18 MV (linac beam). The PSD with an air-core optical fiber with a silica tube also has good energy independence within 1% in the same photon energy range. For the angular dependence, the relative response of all the three modeled PSDs is within 2% for all the angles in a 6 MV photon beam. This is also true in a 300 keV monoenergetic photon beam for PSDs with plastic-core fiber. For the PSD with an air-core fiber with a silica tube in the 300 keV beam, the relative response varies within 1% for most of the angles, except in the case when the fiber stem is pointing right to the radiation source in which case the PSD may over-response by more than 10%. Conclusions: At ±1% level, no beam energy correction is necessary for the response of all three PSDs modeled in this study in the photon energy ranges from 200 keV (monoenergetic) to 18 MV (linac beam). The PSD would be even closer

  9. A comparative study of the radiation hardness of plastic scintillators for the upgrade of the Tile Calorimeter of the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Liao, S.; Erasmus, R.; Jivan, H.; Pelwan, C.; Peters, G.; Sideras-Haddad, E.

    2015-10-01

    The influence of radiation on the light transmittance of plastic scintillators was studied experimentally. The high optical transmittance property of plastic scintillators makes them essential in the effective functioning of the Tile calorimeter of the ATLAS detector at CERN. This significant role played by the scintillators makes this research imperative in the movement towards the upgrade of the tile calorimeter. The radiation damage of polyvinyl toluene (PVT) based plastic scintillators was studied, namely, EJ-200, EJ-208 and EJ-260, all manufactured and provided to us by ELJEN technology. In addition, in order to compare to scintillator brands actually in use at the ATLAS detector currently, two polystyrene (PS) based scintillators and an additional PVT based scintillator were also scrutinized in this study, namely, Dubna, Protvino and Bicron, respectively. All the samples were irradiated using a 6 MeV proton beam at different doses at iThemba LABS Gauteng. The radiation process was planned and mimicked by doing simulations using a SRIM program. In addition, transmission spectra for the irradiated and unirradiated samples of each grade were obtained, observed and analyzed.

  10. Plastic scintillator with effective pulse shape discrimination for neutron and gamma detection

    DOEpatents

    Zaitseva, Natalia P.; Carman, M Leslie; Cherepy, Nerine; Glenn, Andrew M.; Hamel, Sebastien; Payne, Stephen A.; Rupert, Benjamin L.

    2016-04-12

    In one embodiment, a scintillator material includes a polymer matrix; and a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount of 5 wt % or more; wherein the scintillator material exhibits an optical response signature for neutrons that is different than an optical response signature for gamma rays. In another embodiment, a scintillator material includes a polymer matrix; and a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount greater than 10 wt %.

  11. Validating plastic scintillation detectors for photon dosimetry in the radiologic energy range

    SciTech Connect

    Lessard, Francois; Archambault, Louis; Plamondon, Mathieu; and others

    2012-09-15

    Purpose: Photon dosimetry in the kilovolt (kV) energy range represents a major challenge for diagnostic and interventional radiology and superficial therapy. Plastic scintillation detectors (PSDs) are potentially good candidates for this task. This study proposes a simple way to obtain accurate correction factors to compensate for the response of PSDs to photon energies between 80 and 150 kVp. The performance of PSDs is also investigated to determine their potential usefulness in the diagnostic energy range. Methods: A 1-mm-diameter, 10-mm-long PSD was irradiated by a Therapax SXT 150 unit using five different beam qualities made of tube potentials ranging from 80 to 150 kVp and filtration thickness ranging from 0.8 to 0.2 mmAl + 1.0 mmCu. The light emitted by the detector was collected using an 8-m-long optical fiber and a polychromatic photodiode, which converted the scintillation photons to an electrical current. The PSD response was compared with the reference free air dose rate measured with a calibrated Farmer NE2571 ionization chamber. PSD measurements were corrected using spectra-weighted corrections, accounting for mass energy-absorption coefficient differences between the sensitive volumes of the ionization chamber and the PSD, as suggested by large cavity theory (LCT). Beam spectra were obtained from x-ray simulation software and validated experimentally using a CdTe spectrometer. Correction factors were also obtained using Monte Carlo (MC) simulations. Percent depth dose (PDD) measurements were compensated for beam hardening using the LCT correction method. These PDD measurements were compared with uncorrected PSD data, PDD measurements obtained using Gafchromic films, Monte Carlo simulations, and previous data. Results: For each beam quality used, the authors observed an increase of the energy response with effective energy when no correction was applied to the PSD response. Using the LCT correction, the PSD response was almost energy independent, with

  12. Dose rate effects in the radiation damage of the plastic scintillators of the CMS hadron endcap calorimeter

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Litomin, A.; Mossolov, V.; Shumeiko, N.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Spilbeeck, A.; Alves, G. A.; Aldá Júnior, W. L.; Hensel, C.; Carvalho, W.; Chinellato, J.; De Oliveira Martins, C.; Matos Figueiredo, D.; Mora Herrera, C.; Nogima, H.; Prado Da Silva, W. L.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Finger, M.; Finger, M., Jr.; Jain, S.; Khurana, R.; Adamov, G.; Tsamalaidze, Z.; Behrens, U.; Borras, K.; Campbell, A.; Costanza, F.; Gunnellini, P.; Lobanov, A.; Melzer-Pellmann, I.-A.; Muhl, C.; Roland, B.; Sahin, M.; Saxena, P.; Hegde, V.; Kothekar, K.; Pandey, S.; Sharma, S.; Beri, S. B.; Bhawandeep, B.; Chawla, R.; Kalsi, A.; Kaur, A.; Kaur, M.; Walia, G.; Bhattacharya, S.; Ghosh, S.; Nandan, S.; Purohit, A.; Sharan, M.; Banerjee, S.; Bhattacharya, S.; Bhowmik, S.; Chatterjee, S.; Das, P.; Dewanjee, R. K.; Jain, S.; Kumar, S.; Maity, M.; Majumder, G.; Mandakini, P.; Patil, M.; Sarkar, T.; Saikh, A.; Sezen, S.; Juodagalvis, A.; Afanasiev, S.; Bunin, P.; Ershov, Y.; Golutvin, I.; Malakhov, A.; Moisenz, P.; Smirnov, V.; Zarubin, A.; Chadeeva, M.; Chistov, R.; Danilov, M.; Popova, E.; Rusinov, V.; Andreev, Yu.; Dermenev, A.; Karneyeu, A.; Krasnikov, N.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Pozdnyakov, I.; Safronov, G.; Toms, M.; Zhokin, A.; Flacher, H.; Baskakov, A.; Belyaev, A.; Boos, E.; Dubinin, M.; Dudko, L.; Ershov, A.; Gribushin, A.; Kaminskiy, A.; Klyukhin, V.; Kodolova, O.; Lokhtin, I.; Miagkov, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Snigirev, A.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Leonidov, A.; Terkulov, A.; Bitioukov, S.; Elumakhov, D.; Kalinin, A.; Krychkine, V.; Mandrik, P.; Petrov, V.; Ryutin, R.; Sobol, A.; Troshin, S.; Volkov, A.; Adiguzel, A.; Bakirci, N.; Cerci, S.; Damarseckin, S.; Demiroglu, Z. S.; Dozen, C.; Dumanoglu, I.; Eskut, E.; Girgis, S.; Gokbulut, G.; Guler, Y.; Hos, I.; Kangal, E. E.; Kara, O.; Kayis Topaksu, A.; Kiminsu, U.; Oglakci, M.; Onengut, G.; Ozdemir, K.; Ozturk, S.; Polatoz, A.; Sunar Cerci, D.; Tali, B.; Topakli, H.; Turkcapar, S.; Zorbakir, I. S.; Zorbilmez, C.; Bilin, B.; Isildak, B.; Karapinar, G.; Murat Guler, A.; Ocalan, K.; Yalvac, M.; Zeyrek, M.; Gülmez, E.; Kaya, M.; Kaya, O.; Yetkin, E. A.; Yetkin, T.; Cankocak, K.; Sen, S.; Boyarintsev, A.; Grynyov, B.; Levchuk, L.; Popov, V.; Sorokin, P.; Borzou, A.; Call, K.; Dittmann, J.; Hatakeyama, K.; Liu, H.; Pastika, N.; Charaf, O.; Cooper, S. I.; Henderson, C.; Rumerio, P.; West, C.; Arcaro, D.; Gastler, D.; Hazen, E.; Rohlf, J.; Sulak, L.; Wu, S.; Zou, D.; Hakala, J.; Heintz, U.; Kwok, K. H. M.; Laird, E.; Landsberg, G.; Mao, Z.; Gary, J. W.; Ghiasi Shirazi, S. M.; Lacroix, F.; Long, O. R.; Wei, H.; Bhandari, R.; Heller, R.; Stuart, D.; Yoo, J. H.; Apresyan, A.; Chen, Y.; Duarte, J.; Spiropulu, M.; Winn, D.; Abdullin, S.; Banerjee, S.; Chlebana, F.; Freeman, J.; Green, D.; Hare, D.; Hirschauer, J.; Joshi, U.; Lincoln, D.; Los, S.; Pedro, K.; Spalding, W. J.; Strobbe, N.; Tkaczyk, S.; Whitbeck, A.; Linn, S.; Markowitz, P.; Martinez, G.; Bertoldi, M.; Hagopian, S.; Hagopian, V.; Kolberg, T.; Baarmand, M. M.; Noonan, D.; Roy, T.; Yumiceva, F.; Bilki, B.; Clarida, W.; Debbins, P.; Dilsiz, K.; Durgut, S.; Gandrajula, R. P.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Miller, M.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Schmidt, I.; Snyder, C.; Southwick, D.; Tiras, E.; Yi, K.; Al-bataineh, A.; Bowen, J.; Castle, J.; McBrayer, W.; Murray, M.; Wang, Q.; Kaadze, K.; Maravin, Y.; Mohammadi, A.; Saini, L. K.; Baden, A.; Belloni, A.; Eno, S. C.; Ferraioli, C.; Grassi, T.; Hadley, N. J.; Jeng, G.-Y.; Kellogg, R. G.; Kunkle, J.; Mignerey, A.; Ricci-Tam, F.; Shin, Y. H.; Skuja, A.; Tonjes, M. B.; Yang, Z. S.; Apyan, A.; Bierwagen, K.; Brandt, S.; Klute, M.; Niu, X.; Chatterjee, R. M.; Evans, A.; Frahm, E.; Kubota, Y.; Lesko, Z.; Mans, J.; Ruckstuhl, N.; Heering, A.; Karmgard, D. J.; Musienko, Y.; Ruchti, R.; Wayne, M.; Benaglia, A. D.; Medvedeva, T.; Mei, K.; Tully, C.; Bodek, A.; de Barbaro, P.; Galanti, M.; Garcia-Bellido, A.; Khukhunaishvili, A.; Lo, K. H.; Vishnevskiy, D.; Zielinski, M.; Agapitos, A.; Chou, J. P.; Hughes, E.; Saka, H.; Sheffield, D.; Akchurin, N.; Damgov, J.; De Guio, F.; Dudero, P. R.; Faulkner, J.; Gurpinar, E.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Undleeb, S.; Volobouev, I.; Wang, Z.; Goadhouse, S.; Hirosky, R.; Wang, Y.; CMS-HCAL collaboration

    2016-10-01

    We present measurements of the reduction of light output by plastic scintillators irradiated in the CMS detector during the 8 TeV run of the Large Hadron Collider and show that they indicate a strong dose rate effect. The damage for a given dose is larger for lower dose rate exposures. The results agree with previous measurements of dose rate effects, but are stronger due to the very low dose rates probed. We show that the scaling with dose rate is consistent with that expected from diffusion effects.

  13. In-phantom dose verification of prostate IMRT and VMAT deliveries using plastic scintillation detectors.

    PubMed

    Klein, David; Briere, Tina Marie; Kudchadker, Rajat; Archambault, Louis; Beaulieu, Luc; Lee, Andrew; Beddar, Sam

    2012-10-01

    The goal of this work was to demonstrate the feasibility of using a plastic scintillation detector (PSD) incorporated into a prostate immobilization device to verify doses in vivo delivered during intensity-modulated radiation therapy (IMRT) and volumetric modulated-arc therapy (VMAT) for prostate cancer. The treatment plans for both modalities had been developed for a patient undergoing prostate radiation therapy. First, a study was performed to test the dependence, if any, of PSD accuracy on the number and type of calibration conditions. This study included PSD measurements of each treatment plan being delivered under quality assurance (QA) conditions using a rigid QA phantom. PSD results obtained under these conditions were compared to ionization chamber measurements. After an optimal set of calibration factors had been found, the PSD was combined with a commercial endorectal balloon used for rectal distension and prostate immobilization during external beam radiotherapy. This PSD-enhanced endorectal balloon was placed inside of a deformable anthropomorphic phantom designed to simulate male pelvic anatomy. PSD results obtained under these so-called "simulated treatment conditions" were compared to doses calculated by the treatment planning system (TPS). With the PSD still inserted in the pelvic phantom, each plan was delivered once again after applying a shift of 1 cm anterior to the original isocenter to simulate a treatment setup error.The mean total accumulated dose measured using the PSD differed the TPS-calculated doses by less than 1% for both treatment modalities simulated treatment conditions using the pelvic phantom. When the isocenter was shifted, the PSD results differed from the TPS calculations of mean dose by 1.2% (for IMRT) and 10.1% (for VMAT); in both cases, the doses were within the dose range calculated over the detector volume for these regions of steep dose gradient. Our results suggest that the system could benefit prostate cancer patient

  14. In-phantom dose verification of prostate IMRT and VMAT deliveries using plastic scintillation detectors

    PubMed Central

    Klein, David; Briere, Tina Marie; Kudchadker, Rajat; Archambault, Louis; Beaulieu, Luc; Lee, Andrew; Beddar, Sam

    2012-01-01

    The goal of this work was to demonstrate the feasibility of using a plastic scintillation detector (PSD) incorporated into a prostate immobilization device to verify doses in vivo delivered during intensity-modulated radiation therapy (IMRT) and volumetric modulated-arc therapy (VMAT) for prostate cancer. The treatment plans for both modalities had been developed for a patient undergoing prostate radiation therapy. First, a study was performed to test the dependence, if any, of PSD accuracy on the number and type of calibration conditions. This study included PSD measurements of each treatment plan being delivered under quality assurance (QA) conditions using a rigid QA phantom. PSD results obtained under these conditions were compared to ionization chamber measurements. After an optimal set of calibration factors had been found, the PSD was combined with a commercial endorectal balloon used for rectal distension and prostate immobilization during external beam radiotherapy. This PSD-enhanced endorectal balloon was placed inside of a deformable anthropomorphic phantom designed to simulate male pelvic anatomy. PSD results obtained under these so-called “simulated treatment conditions” were compared to doses calculated by the treatment planning system (TPS). With the PSD still inserted in the pelvic phantom, each plan was delivered once again after applying a shift of 1 cm anterior to the original isocenter to simulate a treatment setup error. The mean total accumulated dose measured using the PSD differed the TPS-calculated doses by less than 1% for both treatment modalities simulated treatment conditions using the pelvic phantom. When the isocenter was shifted, the PSD results differed from the TPS calculations of mean dose by 1.2% (for IMRT) and 10.1% (for VMAT); in both cases, the doses were within the dose range calculated over the detector volume for these regions of steep dose gradient. Our results suggest that the system could benefit prostate cancer

  15. Development of a simple-material discrimination method with three plastic scintillator strips for visualizing nuclear reactors

    NASA Astrophysics Data System (ADS)

    Takamatsu, k.; Tanaka, h.; Shoji, d.

    2012-04-01

    The Fukushima Daiichi nuclear disaster is a series of equipment failures and nuclear meltdowns, following the T¯o hoku earthquake and tsunami on 11 March 2011. We present a new method for visualizing nuclear reactors. Muon radiography based on the multiple Coulomb scattering of cosmic-ray muons has been performed. In this work, we discuss experimental results obtained with a cost-effective simple detection system assembled with three plastic scintillator strips. Actually, we counted the number of muons that were not largely deflected by restricting the zenith angle in one direction to 0.8o. The system could discriminate Fe, Pb and C. Materials lighter than Pb can be also discriminated with this system. This method only resolves the average material distribution along the muon path. Therefore the user must make assumptions or interpretations about the structure, or must use more than one detector to resolve the three dimensional material distribution. By applying this method to time-dependent muon radiography, we can detect changes with time, rendering the method suitable for real-time monitoring applications, possibly providing useful information about the reaction process in a nuclear reactor such as burnup of fuels. In nuclear power technology, burnup (also known as fuel utilization) is a measure of how much energy is extracted from a primary nuclear fuel source. Monitoring the burnup of fuels as a nondestructive inspection technique can contribute to safer operation. In nuclear reactor, the total mass is conserved so that the system cannot be monitored by conventional muon radiography. A plastic scintillator is relatively small and easy to setup compared to a gas or layered scintillation system. Thus, we think this simple radiographic method has the potential to visualize a core directly in cases of normal operations or meltdown accidents. Finally, we considered only three materials as a first step in this work. Further research is required to improve the

  16. Non-Carbon Dyes For Platic Scintillators- Report

    SciTech Connect

    Teprovich, J.; Colon-Mercado, H.; Gaillard, J.; Sexton, L.; Washington, A.; Ward, P.; Velten, J.

    2015-10-19

    Scintillation based detectors are desirable for many radiation detection applications (portal and border monitoring, safeguards verification, contamination detection and monitoring). The development of next generation scintillators will require improved detection sensitivity for weak gamma ray sources, and fast and thermal neutron quantification. Radiation detection of gamma and neutron sources can be accomplished with organic scintillators, however, the single crystals are difficult to grow for large area detectors and subject to cracking. Alternatives to single crystal organic scintillators are plastic scintillators (PS) which offer the ability to be shaped and scaled up to produce large sized detectors. PS is also more robust than the typical organic scintillator and are ideally suited for deployment in harsh real-world environments. PS contain a mixture of dyes to down-convert incident radiation into visible light that can be detected by a PMT. This project will evaluate the potential use of nano-carbon dyes in plastic scintillators.

  17. Plastic scintillators with high loading of one or more metal carboxylates

    DOEpatents

    Cherepy, Nerine; Sanner, Robert Dean

    2016-01-12

    In one embodiment, a material includes at least one metal compound incorporated into a polymeric matrix, where the metal compound includes a metal and one or more carboxylate ligands, where at least one of the one or more carboxylate ligands includes a tertiary butyl group, and where the material is optically transparent. In another embodiment, a method includes: processing pulse traces corresponding to light pulses from a scintillator material; and outputting a result of the processing, where the scintillator material comprises at least one metal compound incorporated into a polymeric matrix, the at least one metal compound including a metal and one or more carboxylate ligands, where at least one of the one or more carboxylate ligands has a tertiary butyl group, and where the scintillator material is optically transparent and has an energy resolution at 662 keV of less than about 20%.

  18. Neutron detection and multiplicity counting using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array

    SciTech Connect

    Miller, M.C.

    1998-03-01

    Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection ({sup 10}B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where {sup 3}He proportional counters are embedded in a polyethylene matrix. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on a pulse-by-pulse basis using custom integrator and timing circuits. In addition, a custom time-tag module was used to provide a time for each detector event. Analysis of the combined energy and time event stream was performed by calibrating each detector`s response and filtering based on the presence of a simultaneous energy deposition corresponding to the {sup 10}B(n,alpha) reaction products in the plastic scintillator (93 keV{sub ee}) and the accompanying neutron-capture gamma ray in the bismuth germanate (478 keV). Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift-register-type singles and doubles count rates. Proof-of-principle measurements were conducted with a variety of gamma-ray and neutron sources including {sup 137}Cs, {sup 54}Mn, AmLi, and {sup 252}Cf. Results of this study indicate that a neutron-capture probability of {approximately}10% and a die-away time of {approximately}10 {micro}s are possible with a 4-detector array with a detector volume of 1600 cm{sup 3}. Simulations were performed that indicate neutron-capture probabilities on the order of 50% and die-away times of less than 4 {micro}s are realistically achievable. While further study will be required for practical application of such a detection system, the results obtained in this

  19. Three-dimensional photograph of electron tracks through a plastic scintillator

    NASA Astrophysics Data System (ADS)

    Filipenko, Mykhaylo; Iskhakov, Timur; Hufschmidt, Patrick; Anton, Gisela; Campbell, Michael; Gleixner, Thomas; Leuchs, Gerd; Tick, Timo; Vallerga, John; Wagenpfeil, Michael; Michel, Thilo

    2014-11-01

    The reconstruction of particle trajectories makes it possible to distinguish between different types of charged particles. In high-energy physics, where trajectories are rather long (several meters), large size trackers must be used to achieve sufficient position resolution. However, in low-background experiments like the search for neutrinoless double beta decay, tracks are rather short (some mm to several cm, depending on the detector in use) and three-dimensional trajectories could only be resolved in gaseous time-projection chambers so far. For detectors of a large volume of around one cubic meter (large in the scope of neutrinoless double beta search) and therefore large drift distances (several decimeters to 1 m), this technique is limited by diffusion and repulsion of charge carriers. In this work we present a "proof-of-principle" experiment for a new method of the three-dimensional tracking of charged particles by scintillation light: we used a setup consisting of a scintillator, mirrors, lenses, and a novel imaging device (the hybrid photon detector) in order to image two projections of electron tracks through the scintillator. We took data at the T-22 beamline at DESY with relativistic electrons with a kinetic energy of 5 GeV and from this data successfully reconstructed their three-dimensional propagation path in the scintillator. With our setup we achieved a position resolution in the range of 170-248 µm.

  20. On the use of a single-fiber multipoint plastic scintillation detector for 192Ir high-dose-rate brachytherapy

    PubMed Central

    Therriault-Proulx, François; Beddar, Sam; Beaulieu, Luc

    2013-01-01

    Purpose: The goal of this study was to prove the feasibility of using a single-fiber multipoint plastic scintillation detector (mPSD) as an in vivo verification tool during 192Ir high-dose-rate brachytherapy treatments. Methods: A three-point detector was built and inserted inside a catheter-positioning template placed in a water phantom. A hyperspectral approach was implemented to discriminate the different optical signals composing the light output at the exit of the single collection optical fiber. The mPSD was tested with different source-to-detector positions, ranging from 1 to 5 cm radially and over 10.5 cm along the longitudinal axis of the detector, and with various integration times. Several strategies for improving the accuracy of the detector were investigated. The device's accuracy in detecting source position was also tested. Results: Good agreement with the expected doses was obtained for all of the scintillating elements, with average relative differences from the expected values of 3.4 ± 2.1%, 3.0 ± 0.7%, and 4.5 ± 1.0% for scintillating elements from the distal to the proximal. A dose threshold of 3 cGy improved the general accuracy of the detector. An integration time of 3 s offered a good trade-off between precision and temporal resolution. Finally, the mPSD measured the radioactive source positioning uncertainty to be no more than 0.32 ± 0.06 mm. The accuracy and precision of the detector were improved by a dose-weighted function combining the three measurement points and known details about the geometry of the detector construction. Conclusions: The use of a mPSD for high-dose-rate brachytherapy dosimetry is feasible. This detector shows great promise for development of in vivo applications for real-time verification of treatment delivery. PMID:23718599

  1. Preliminary evaluation of the dosimetric accuracy of the in vivo plastic scintillation detector OARtrac system for prostate cancer treatments

    PubMed Central

    Klawikowski, Slade J.; Zeringue, Clint; Wootton, Landon S.; Ibbott, Geoffrey S.; Beddar, Sam

    2014-01-01

    A promising, new, in vivo prostate dosimetry system has been developed for clinical radiation therapy. This work outlines the preliminary end-to-end testing of the accuracy and precision of the new OARtrac scintillation dosimetry system. We tested 94 calibrated plastic scintillation detector (PSD) probes before their final integration into endorectal balloon assemblies. These probes had been calibrated at The University of Texas MD Anderson Cancer Center Dosimetry Laboratory (MDADL). We used a complete clinical OARtrac system including the PSD probes, charge coupled device (CCD camera) monitoring system, and the manufacturer’s integrated software package. The PSD probes were irradiated at 6 MV in a Solid Water® phantom. Irradiations were performed with a 6 MV linear accelerator using anterior-posterior/posterior-anterior (AP/PA) matched fields to a maximum dose of 200 cGy in a 100 cm source-axis distance (SAD geometry. As a whole, the OARtrac system has good accuracy with a mean error of 0.01% and an error spread of ± 5.4% at the 95% confidence interval. These results reflect the PSD probes’ accuracy before their final insertion into endorectal balloons. Future work will test the dosimetric effects of mounting the PSD probes within the endorectal balloon assemblies. PMID:24732073

  2. Plastic scintillators in coincidence for the study of multi-particle production of sea level cosmic rays in dense medium

    NASA Technical Reports Server (NTRS)

    Chuang, L. S.; Chan, K. W.; Wada, M.

    1985-01-01

    Cosmic ray particles at sea level penetrate a thick layer of dense medium without appreciable interaction. These penetrating particles are identified with muons. The only appreciable interaction of muons are by knock on processes. A muon may have single, double or any number of knock on with atoms of the material so that one, two, three or more particles will come out from the medium in which the knock on processes occur. The probability of multiparticle production is expected to decrease with the increase of multiplicity. Measurements of the single, double, and triple particles generated in a dense medium (Fe and Al) by sea level cosmic rays at 22.42 N. Lat. and 114.20 E. Long. (Hong Kong) are presented using a detector composed of two plastic scintillators connected in coincidence.

  3. SHIELDING AND DETECTOR RESPONSE CALCULATIONS PERTAINING TO CATEGORY 1 QUANTITIES OF PLUTONIUM AND HAND-HELD PLASTIC SCINTILLATORS

    SciTech Connect

    Couture, A.

    2013-06-07

    Nuclear facilities sometimes use hand-held plastic scintillator detectors to detect attempts to divert special nuclear material in situations where portal monitors are impractical. MCNP calculations have been performed to determine the neutron and gamma radiation field arising from a Category I quantity of weapons-grade plutonium in various shielding configurations. The shields considered were composed of combinations of lead and high-density polyethylene such that the mass of the plutonium plus shield was 22.7 kilograms. Monte-Carlo techniques were also used to determine the detector response to each of the shielding configurations. The detector response calculations were verified using field measurements of high-, medium-, and low- energy gamma-ray sources as well as a Cf-252 neutron source.

  4. SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator

    NASA Astrophysics Data System (ADS)

    Gardés, E.; Balanzat, E.; Ban-d'Etat, B.; Cassimi, A.; Durantel, F.; Grygiel, C.; Madi, T.; Monnet, I.; Ramillon, J.-M.; Ropars, F.; Lebius, H.

    2013-02-01

    We developed a new sub-nanosecond time-resolved instrument to study the dynamics of UV-visible luminescence under high stopping power heavy ion irradiation. We applied our instrument, called SPORT, on a fast plastic scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean electronic stopping power of 2.6 MeV/μm. As a consequence of increasing permanent radiation damages with increasing ion fluence, our investigations reveal a degradation of scintillation intensity together with, thanks to the time-resolved measurement, a decrease in the decay constant of the scintillator. This combination indicates that luminescence degradation processes by both dynamic and static quenching, the latter mechanism being predominant. Under such high density excitation, the scintillation deterioration of BC-400 is significantly enhanced compared to that observed in previous investigations, mainly performed using light ions. The observed non-linear behaviour implies that the dose at which luminescence starts deteriorating is not independent on particles' stopping power, thus illustrating that the radiation hardness of plastic scintillators can be strongly weakened under high excitation density in heavy ion environments.

  5. A plastic scintillator-based 2D thermal neutron mapping system for use in BNCT studies.

    PubMed

    Ghal-Eh, N; Green, S

    2016-06-01

    In this study, a scintillator-based measurement instrument is proposed which is capable of measuring a two-dimensional map of thermal neutrons within a phantom based on the detection of 2.22MeV gamma rays generated via nth+H→D+γ reaction. The proposed instrument locates around a small rectangular water phantom (14cm×15cm×20cm) used in Birmingham BNCT facility. The whole system has been simulated using MCNPX 2.6. The results confirm that the thermal flux peaks somewhere between 2cm and 4cm distance from the system entrance which is in agreement with previous studies. PMID:26986813

  6. SU-E-T-423: TrueBeam Small Field Dosimetry Using Commercial Plastic Scintillation and Other Stereotactic Detectors

    SciTech Connect

    Pino, R; Therriault-Proulx, F; Wang, X; Yang, J; Beddar, S

    2014-06-01

    Purpose: To perform dose profile and output factor (OF) measurements with the Exradin W1 plastic scintillation detector (PSD) for small fields made by the high-definition multi-leaf collimator (MLC) on the TrueBeam STx system and to compare them to values measured with an IBA CC01 ionization chamber and a Sun Nuclear Edge detector diode for 6 MV photon beams. Methods: The Exradin W1 is a new small volume near-water equivalent and energy independent PSD manufactured by Standard Imaging, Inc. All measurements were performed in an IBA Blue Phantom water tank. Square MLC-shaped fields with sides ranging from 0.5 cm to 2 cm and jawshaped fields with sides ranging from 1 cm to 40 cm were measured using an SAD setup at 10 cm depth. Dose profile and percent depth dose (PDD) measurements were also taken under the same conditions for MLC fields 0.5×0.5 and 1×1 cm2 in size with jaws at 2×2cm2. The CC01 and W1 were vertically mounted. Results: OFs measured with the W1 for jaw only square fields were consistent with the ones measured with a Farmers PTW TN33013 ion chamber (1.8% maximum deviation). OF and penumbra measurement results are presented below. PDDs measured for all detectors are within 1.5% for the 0.5×0.5 cm2 and within 1% for the 1×1 cm2 MLC fields.Output factors:MLC size W1 CC01 EDGE0.5cm 0.555 0.541 0.5851.0cm 0.716 0.702 0.7331.5cm 0.779 0.761 0.7772.0cm 0.804 0.785 0.796Penumbras (mm):MLC size W1 CC01 EDGE0.5cm 2.7 2.9 2.51.0cm 3.0 3.4 2. Conclusion: OFs measured for small MLC fields were consistent with the ones measured with the other stereotactic detectors. Measured penumbras are consistent with detector size. The Exradin W1 PSD is an excellent choice for characterizing MLC-shaped small beam dosimetry used for stereotactic radiosurgery and body radiation therapy. Sam Beddar would like to disclose a NIH/NCI SBIR Phase II grant (2R44CA153824-02A1) with Standard Imaging, Title: “Water-Equivalent Plastic Scintillation Detectors for Small Field

  7. SU-E-T-476: Quality Assurance for Gamma Knife Perfexion Using the Exradin W1 Plastic Scintillation Detector

    SciTech Connect

    Pino, R; Therriault-Proulx, F; Yang, J; Beddar, S

    2014-06-01

    Purpose: To perform dose profile and output factor measurements for the Exradin W1 plastic scintillation detector (PSD) for the Gamma Knife Perfexion (GKP) collimators in a Lucy phantom and to compare these values to an Exradin A16 ion chamber, EBT3 radiochromic film and treatment planning system (TPS) data. Methods: We used the Exradin W1 PSD which has a small volume, near-water equivalent sensitive element. It has also been shown to be energy independent. This new detector is manufactured and distributed by Standard Imaging, Inc. Measurements were performed for all three collimators (4 mm, 8 mm and 16 mm) for the GKP. The Lucy phantom with the PSD inserted was moved in small steps to acquire profiles in all three directions. EBT3 film was inserted in the Lucy phantom and exposed to a single shot for each collimator. Relative output factors were measured using the three detectors while profiles acquired with the PSD were compared to the ones measured with EBT3 radiochromic film. Results: Measured output factors relative to the largest collimator are as followsCollimator PS EBT3 A1616mm 1.000 1.000 1.0008mm 0.892 0.881 0.8834mm 0.795 0.793 0.727 The nominal (vendor) OFs for GKP are 1.000, 0.900, and 0.814, for collimators 16 mm, 8 mm and 4 mm, respectively. There is excellent agreement between all profiles measured with the PSD and EBT3 as well as with the TPS data provided by the vendor. Conclusion: Output factors measured with the W1 were consistent with the ones measured with EBT3 and A16 ion chamber. Measured profiles are in excellent agreement. The W1 detector seems well suited for beam QA for Gamma Knife due to its dosimetric characteristics. Sam Beddar would like to disclose a NIH/NCI SBIR Phase II grant (2R44CA153824-02A1) with Standard Imaging, Title: “Water-Equivalent Plastic Scintillation Detectors for Small Field Radiotherapy”.

  8. Development of proton CT imaging system using plastic scintillator and CCD camera

    NASA Astrophysics Data System (ADS)

    Tanaka, Sodai; Nishio, Teiji; Matsushita, Keiichiro; Tsuneda, Masato; Kabuki, Shigeto; Uesaka, Mitsuru

    2016-06-01

    A proton computed tomography (pCT) imaging system was constructed for evaluation of the error of an x-ray CT (xCT)-to-WEL (water-equivalent length) conversion in treatment planning for proton therapy. In this system, the scintillation light integrated along the beam direction is obtained by photography using the CCD camera, which enables fast and easy data acquisition. The light intensity is converted to the range of the proton beam using a light-to-range conversion table made beforehand, and a pCT image is reconstructed. An experiment for demonstration of the pCT system was performed using a 70 MeV proton beam provided by the AVF930 cyclotron at the National Institute of Radiological Sciences. Three-dimensional pCT images were reconstructed from the experimental data. A thin structure of approximately 1 mm was clearly observed, with spatial resolution of pCT images at the same level as that of xCT images. The pCT images of various substances were reconstructed to evaluate the pixel value of pCT images. The image quality was investigated with regard to deterioration including multiple Coulomb scattering.

  9. Development of proton CT imaging system using plastic scintillator and CCD camera.

    PubMed

    Tanaka, Sodai; Nishio, Teiji; Matsushita, Keiichiro; Tsuneda, Masato; Kabuki, Shigeto; Uesaka, Mitsuru

    2016-06-01

    A proton computed tomography (pCT) imaging system was constructed for evaluation of the error of an x-ray CT (xCT)-to-WEL (water-equivalent length) conversion in treatment planning for proton therapy. In this system, the scintillation light integrated along the beam direction is obtained by photography using the CCD camera, which enables fast and easy data acquisition. The light intensity is converted to the range of the proton beam using a light-to-range conversion table made beforehand, and a pCT image is reconstructed. An experiment for demonstration of the pCT system was performed using a 70 MeV proton beam provided by the AVF930 cyclotron at the National Institute of Radiological Sciences. Three-dimensional pCT images were reconstructed from the experimental data. A thin structure of approximately 1 mm was clearly observed, with spatial resolution of pCT images at the same level as that of xCT images. The pCT images of various substances were reconstructed to evaluate the pixel value of pCT images. The image quality was investigated with regard to deterioration including multiple Coulomb scattering. PMID:27191962

  10. Study of the response of plastic scintillation detectors in small-field 6 MV photon beams by Monte Carlo simulations

    PubMed Central

    Wang, Lilie L. W.; Beddar, Sam

    2011-01-01

    Purpose: To investigate the response of plastic scintillation detectors (PSDs) in a 6 MV photon beam of various field sizes using Monte Carlo simulations. Methods: Three PSDs were simulated: A BC-400 and a BCF-12, each attached to a plastic-core optical fiber, and a BC-400 attached to an air-core optical fiber. PSD response was calculated as the detector dose per unit water dose for field sizes ranging from 10×10 down to 0.5×0.5 cm2 for both perpendicular and parallel orientations of the detectors to an incident beam. Similar calculations were performed for a CC01 compact chamber. The off-axis dose profiles were calculated in the 0.5×0.5 cm2 photon beam and were compared to the dose profile calculated for the CC01 chamber and that calculated in water without any detector. The angular dependence of the PSDs’ responses in a small photon beam was studied. Results: In the perpendicular orientation, the response of the BCF-12 PSD varied by only 0.5% as the field size decreased from 10×10 to 0.5×0.5 cm2, while the response of BC-400 PSD attached to a plastic-core fiber varied by more than 3% at the smallest field size because of its longer sensitive region. In the parallel orientation, the response of both PSDs attached to a plastic-core fiber varied by less than 0.4% for the same range of field sizes. For the PSD attached to an air-core fiber, the response varied, at most, by 2% for both orientations. Conclusions: The responses of all the PSDs investigated in this work can have a variation of only 1%–2% irrespective of field size and orientation of the detector if the length of the sensitive region is not more than 2 mm long and the optical fiber stems are prevented from pointing directly to the incident source. PMID:21520871

  11. Extraction of depth-dependent perturbation factors for parallel-plate chambers in electron beams using a plastic scintillation detector

    SciTech Connect

    Lacroix, Frederic; Guillot, Mathieu; McEwen, Malcolm; Cojocaru, Claudiu; Gingras, Luc; Beddar, A. Sam; Beaulieu, Luc

    2010-08-15

    Purpose: This work presents the experimental extraction of the overall perturbation factor P{sub Q} in megavoltage electron beams for NACP-02 and Roos parallel-plate ionization chambers using a plastic scintillation detector (PSD). Methods: The authors used a single scanning PSD mounted on a high-precision scanning tank to measure depth-dose curves in 6, 12, and 18 MeV clinical electron beams. The authors also measured depth-dose curves using the NACP-02 and PTW Roos chambers. Results: The authors found that the perturbation factors for the NACP-02 and Roos chambers increased substantially with depth, especially for low-energy electron beams. The experimental results were in good agreement with the results of Monte Carlo simulations reported by other investigators. The authors also found that using an effective point of measurement (EPOM) placed inside the air cavity reduced the variation of perturbation factors with depth and that the optimal EPOM appears to be energy dependent. Conclusions: A PSD can be used to experimentally extract perturbation factors for ionization chambers. The dosimetry protocol recommendations indicating that the point of measurement be placed on the inside face of the front window appear to be incorrect for parallel-plate chambers and result in errors in the R{sub 50} of approximately 0.4 mm at 6 MeV, 1.0 mm at 12 MeV, and 1.2 mm at 18 MeV.

  12. Real-time in vivo rectal wall dosimetry using plastic scintillation detectors for patients with prostate cancer

    NASA Astrophysics Data System (ADS)

    Wootton, Landon; Kudchadker, Rajat; Lee, Andrew; Beddar, Sam

    2014-02-01

    We designed and constructed an in vivo dosimetry system using plastic scintillation detectors (PSDs) to monitor dose to the rectal wall in patients undergoing intensity-modulated radiation therapy for prostate cancer. Five patients were enrolled in an Institutional Review Board-approved protocol for twice weekly in vivo dose monitoring with our system, resulting in a total of 142 in vivo dose measurements. PSDs were attached to the surface of endorectal balloons used for prostate immobilization to place the PSDs in contact with the rectal wall. Absorbed dose was measured in real time and the total measured dose was compared with the dose calculated by the treatment planning system on the daily computed tomographic image dataset. The mean difference between measured and calculated doses for the entire patient population was -0.4% (standard deviation 2.8%). The mean difference between daily measured and calculated doses for each patient ranged from -3.3% to 3.3% (standard deviation ranged from 5.6% to 7.1% for four patients and was 14.0% for the last, for whom optimal positioning of the detector was difficult owing to the patient's large size). Patients tolerated the detectors well and the treatment workflow was not compromised. Overall, PSDs performed well as in vivo dosimeters, providing excellent accuracy, real-time measurement and reusability.

  13. A method to correct for temperature dependence and measure simultaneously dose and temperature using a plastic scintillation detector

    PubMed Central

    Therriault-Proulx, Francois; Wootton, Landon; Beddar, Sam

    2015-01-01

    Plastic scintillation detectors (PSDs) work well for radiation dosimetry. However, they show some temperature dependence, and a priori knowledge of the temperature surrounding the PSD is required to correct for this dependence. We present a novel approach to correct PSD response values for temperature changes instantaneously and without the need for prior knowledge of the temperature value. In addition to rendering the detector temperature-independent, this approach allows for actual temperature measurement using solely the PSD apparatus. With a temperature-controlled water tank, the temperature was varied from room temperature to more than 40°C and the PSD was used to measure the dose delivered from a cobalt-60 photon beam unit to within an average of 0.72% from the expected value. The temperature was measured during each acquisition with the PSD and a thermocouple and values were within 1°C of each other. The depth-dose curve of a 6-MV photon beam was also measured under warm non-stable conditions and this curve agreed to within an average of −0.98% from the curve obtained at room temperature. The feasibility of rendering PSDs temperature-independent was demonstrated with our approach, which also enabled simultaneous measurement of both dose and temperature. This novel approach improves both the robustness and versatility of PSDs. PMID:26407188

  14. A design methodology using signal-to-noise ratio for plastic scintillation detectors design and performance optimization

    PubMed Central

    Lacroix, Frédéric; Beddar, A. Sam; Guillot, Mathieu; Beaulieu, Luc; Gingras, Luc

    2009-01-01

    Purpose: The design of novel plastic scintillation detectors (PSDs) is impeded by the lack of a suitable framework to simulate and predict their performance. The authors propose to use the signal-to-noise ratio (SNR) to model the performance of PSDs that use charge-coupled devices (CCDs) as photodetectors. Methods: In PSDs using CCDs, the SNR is inversely related to the normalized standard deviation of the dose measurement. Thus, optimizing the SNR directly optimizes the system’s precision. In this work, a model of SNR as a function of the system parameters is derived for optical fiber-based PSD systems. Furthermore, this proposed model is validated using experimental results. A formula for the efficiency of fiber coupling to CCDs is derived and used to simulate the performance of a PSD under varying magnifications. Results: The proposed model is shown to simulate the experimental performance of an actual PSD to a suitable degree of accuracy under various conditions. Conclusions: The SNR constitutes a useful tool to simulate the dosimetric precision of PSDs. Using the SNR model, recommendations for the design and optimization of PSDs are provided. Using the same framework, recommendations for non-fiber-based PSDs are also provided. PMID:19994531

  15. Development of a novel multi-point plastic scintillation detector with a single optical transmission line for radiation dose measurement*

    PubMed Central

    Therriault-Proulx, François; Archambault, Louis; Beaulieu, Luc; Beddar, Sam

    2013-01-01

    Purpose The goal of this study was to develop a novel multi-point plastic scintillation detector (mPSD) capable of measuring the dose accurately at multiple positions simultaneously using a single optical transmission line. Methods A 2-point mPSD used a band-pass approach that included splitters, color filters, and an EMCCD camera. The 3-point mPSD was based on a new full-spectrum approach, in which a spectrograph was coupled to a CCD camera. Irradiations of the mPSDs and of an ion chamber were performed with a 6-MV photon beam at various depths and lateral positions in a water tank. Results For the 2-point mPSD, the average relative differences between mPSD and ion chamber measurements for the depth-dose were 2.4±1.6% and 1.3±0.8% for BCF-60 and BCF-12, respectively. For the 3-point mPSD, the average relative differences over all conditions were 2.3±1.1%, 1.6±0.4%, and 0.32±0.19% for BCF-60, BCF-12, and BCF-10, respectively. Conclusions This study demonstrates the practical feasibility of mPSDs. This type of detector could be very useful for pre-treatment quality assurance applications as well as an accurate tool for real-time in vivo dosimetry. PMID:23060069

  16. Real-time in vivo rectal wall dosimetry using plastic scintillation detectors for patients with prostate cancer

    PubMed Central

    Wootton, Landon; Kudchadker, Rajat; Lee, Andrew; Beddar, Sam

    2014-01-01

    We designed and constructed an in vivo dosimetry system using plastic scintillation detectors (PSDs) to monitor dose to the rectal wall in patients undergoing intensity-modulated radiation therapy for prostate cancer. Five patients were enrolled in an Institutional Review Board–approved protocol for twice weekly in vivo dose monitoring with our system, resulting in a total of 142 in vivo dose measurements. PSDs were attached to the surface of endorectal balloons used for prostate immobilization to place the PSDs in contact with the rectal wall. Absorbed dose was measured in real time and the total measured dose was compared with the dose calculated by the treatment planning system on the daily CT image dataset. The mean difference between measured and calculated doses for the entire patient population was −0.4% (standard deviation 2.8%). The mean difference between daily measured and calculated doses for each patient ranged from −3.3% to 3.3% (standard deviation ranged from 5.6% to 7.1% for 4 patients and was 14.0% for the last, for whom optimal positioning of the detector was difficult owing to the patient’s large size). Patients tolerated the detectors well and the treatment workflow was not compromised. Overall, PSDs performed well as in vivo dosimeters, providing excellent accuracy, real-time measurement, and reusability. PMID:24434775

  17. Measuring output factors of small fields formed by collimator jaws and multileaf collimator using plastic scintillation detectors

    SciTech Connect

    Klein, David M.; Tailor, Ramesh C.; Archambault, Louis; Wang, Lilie; Therriault-Proulx, Francois; Beddar, A. Sam

    2010-10-15

    Purpose: As the practice of using high-energy photon beams to create therapeutic radiation fields of subcentimeter dimensions (as in intensity-modulated radiotherapy or stereotactic radiosurgery) grows, so too does the need for accurate verification of beam output at these small fields in which standard practices of dose verification break down. This study investigates small-field output factors measured using a small plastic scintillation detector (PSD), as well as a 0.01 cm{sup 3} ionization chamber. Specifically, output factors were measured with both detectors using small fields that were defined by either the X-Y collimator jaws or the multileaf collimator (MLC). Methods: A PSD of 0.5 mm diameter and 2 mm length was irradiated with 6 and 18 MV linac beams. The PSD was positioned vertically at a source-to-axis distance of 100 cm, at 10 cm depth in a water phantom, and irradiated with fields ranging in size from 0.5x0.5 to 10x10 cm{sup 2}. The field sizes were defined either by the collimator jaws alone or by a MLC alone. The MLC fields were constructed in two ways: with the closed leaves (i.e., those leaves that were not opened to define the square field) meeting at either the field center line or at a 4 cm offset from the center line. Scintillation light was recorded using a CCD camera and an estimation of error in the median-filtered signals was made using the bootstrapping technique. Measurements were made using a CC01 ionization chamber under conditions identical to those used for the PSD. Results: Output factors measured by the PSD showed close agreement with those measured using the ionization chamber for field sizes of 2.0x2.0 cm{sup 2} and above. At smaller field sizes, the PSD obtained output factors as much as 15% higher than those found using the ionization chamber by 0.6x0.6 cm{sup 2} jaw-defined fields. Output factors measured with no offset of the closed MLC leaves were as much as 20% higher than those measured using a 4 cm leaf offset

  18. Scattering height estimation using scintillating Wide Area Augmentation System/Satellite Based Augmentation System and GPS satellite signals

    NASA Astrophysics Data System (ADS)

    Cerruti, A. P.; Ledvina, B. M.; Kintner, P. M.

    2006-12-01

    An experiment to measure equatorial amplitude scintillations on the geostationary Wide Area Augmentation System (WAAS) Satellite Based Augmentation System (SBAS) signal was conducted in Cachoeira Paulista (22.70°S, 45.01°W geographic coordinates; -17.74°N, 21.74°E geomagnetic coordinates), Brazil from December 2003 through February 2004. The purpose of this paper is to estimate the scattering height of the irregularities using the WAAS signal scintillations as compared to nearby Global Positioning System (GPS) signal scintillations. Estimating the scattering height is important because the calculated zonal drift velocity of the irregularities using the measured scintillation pattern velocity on the ground is height dependent. Accurate height estimation is also required if one wishes to develop phase screen scintillation models. The difference in the pattern velocities is due to the different signal puncture point velocities with respect to the ionospheric drift. Two east-west receivers are used to measure the scintillation pattern drift velocity and to compare the results of the geostationary WAAS satellite signal to that of a GPS satellite signal, which has a nonzero ionospheric signal puncture point velocity. By varying the assumed scattering height for the measurements from the nearby GPS signal, the zonal velocity measurements from the GPS scintillations can be matched to those of the WAAS scintillations, and a scattering height estimate can be made. When the puncture points have minimal separation, the inferred ionospheric irregularity zonal velocities should be equal. On the two nights for which data are available, scattering height estimates of 669 ± 209 km for the first night and 388 ± 139 km for the second night were obtained. On the second night, the reported mean hmF2 as calculated using a collocated Digisonde was 385 ± 17 km over the same period as the GPS/WAAS scattering height estimate. The geometry of this experiment was not optimal, but

  19. Determination of the quenching correction factors for plastic scintillation detectors in therapeutic high-energy proton beams

    PubMed Central

    Wang, L L W; Perles, L A; Archambault, L; Sahoo, N; Mirkovic, D; Beddar, S

    2013-01-01

    The plastic scintillation detectors (PSD) have many advantages over other detectors in small field dosimetry due to its high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs will undergo a quenching effect which makes the signal level reduced significantly when the detector is close to Bragg peak where the linear energy transfer (LET) for protons is very high. This study measures the quenching correction factor (QCF) for a PSD in clinical passive-scattering proton beams and investigates the feasibility of using PSDs in depth-dose measurements in proton beams. A polystyrene based PSD (BCF-12, ϕ0.5mm×4mm) was used to measure the depth-dose curves in a water phantom for monoenergetic unmodulated proton beams of nominal energies 100, 180 and 250 MeV. A Markus plane-parallel ion chamber was also used to get the dose distributions for the same proton beams. From these results, the QCF as a function of depth was derived for these proton beams. Next, the LET depth distributions for these proton beams were calculated by using the MCNPX Monte Carlo code, based on the experimentally validated nozzle models for these passive-scattering proton beams. Then the relationship between the QCF and the proton LET could be derived as an empirical formula. Finally, the obtained empirical formula was applied to the PSD measurements to get the corrected depth-dose curves and they were compared to the ion chamber measurements. A linear relationship between QCF and LET, i.e. Birks' formula, was obtained for the proton beams studied. The result is in agreement with the literature. The PSD measurements after the quenching corrections agree with ion chamber measurements within 5%. PSDs are good dosimeters for proton beam measurement if the quenching effect is corrected appropriately. PMID:23128412

  20. Design of a muon tomography system with a plastic scintillator and wavelength-shifting fiber arrays

    NASA Astrophysics Data System (ADS)

    Jo, Woo Jin; Kim, Hyun-Il; An, Su Jung; Lee, Chae Young; Baek, Cheol-Ha; Chung, Yong Hyun

    2013-12-01

    Recently, monitoring nuclear materials to avoid nuclear terrorism has become an important area of national security. It can be difficult to detect gamma rays from nuclear material because they are easily shielded by shielding material. Muon tomography using multiple -Coulomb scattering derived from muons can be utilized to detect special nuclear materials (SNMs) such as uranium-235 and plutonium-239. We designed a muon tomography system composed of four detector modules. The incident and scattered muon tracks can be calculated by two top and two bottom detectors, respectively. 3D tomographic images are obtained by extracting the crossing points of muon tracks with a point-of-closest-approach algorithm. The purpose of this study was to optimize the muon tomography system using Monte Carlo simulation code. The effects of the geometric parameters of the muon tomography system on material Z-discrimination capability were simulated and evaluated.

  1. SU-C-304-03: Experimental Investigation On the Accuracy of Plastic Scintillation Dosimeters in Small Fields

    SciTech Connect

    Papaconstadopoulos, P; Archambault, L; Seuntjens, J

    2015-06-15

    Purpose: To investigate the accuracy of the Exradin W1 (SI) and of an “in-house” plastic scintillation dosimeter (CHUQ PSD) in small radiation fields. Methods: Output factor (OF) measurements with the W1 and CHUQ PSD were performed for field sizes of 0.5 x 0.5, 1 x 1 and 2 x 2 cm{sup 2}. Both detectors were placed parallel to the central axis (CAX) in water. The spectrum discrimination calibration method was performed in each set-up to account for the Cerenkov (CRV) signal created in the fiber. The OFs were compared to the expected field factors in water derived using i) Monte Carlo (MC) simulations of an accurate accelerator model and ii) microLion (PTW) and D1V diode (SI) OFs. MC-derived correction factors were applied to both the microLion and D1V OFs. For the CHUQ PSD the calibration was repeated in water (// CAX), solid water (perpendicular to CAX) and under a shielded configuration. The signal was collected using a spectrometer (wavelength range = 185–1100 nm). Spectral analysis was performed to evaluate potential changes of the spectral distributions under the various calibration set-up configurations. Results: The W1 OFs presented an over-response for the 0.5 x 0.5 cm{sup 2} in the range of 3 – 4.1% relative to the expected field factor. The CHUQ PSD presented an under-response in the range of 1.5 – 2.7%, without accounting for volume averaging. The CRV spectra under the various calibration procedures appeared similar to each other and only minor changes were observed to the respective OFs. Conclusion: The W1 and CHUQ PSD can be used in small fields down to a 1 x 1 cm{sup 2} field size. Discrepancies were encountered between the two detectors for the smallest field size of 0.5 x 0.5 cm{sup 2} with the CHUQ PSD exhibiting a closer agreement to the expected field factor. Funding sources: 1) Alexander S. Onassis Public Benefit Foundation in Greece and 2) CREATE Medical Physics Research Training Network grant of the Natural Sciences and Engineering

  2. SU-C-BRD-06: Results From a 5 Patient in Vivo Rectal Wall Dosimetry Study Using Plastic Scintillation Detectors

    SciTech Connect

    Wootton, L; Kudchadker, R; Lee, A; Beddar, S

    2014-06-15

    Purpose: To evaluate the performance characteristics of plastic scintillation detectors (PSDs) in an in vivo environment for external beam radiation, and to establish the usefulness and ease of implementation of a PSD based in vivo dosimetry system for routine clinical use. Methods: A five patient IRB approved in vivo dosimetry study was performed. Five patients with prostate cancer were enrolled and PSDs were used to monitor rectal wall dose and verify the delivered dose for approximately two fractions each week over the course of their treatment (approximately fourteen fractions), resulting in a total of 142 in vivo measurements. A set of two PSDs was fabricated for each patient. At each monitored fraction the PSDs were attached to the anterior surface of an endorectal balloon used to immobilize the patient's prostate during treatment. A CT scan was acquired with a CTon- rails linear accelerator to localize the detectors and to calculate the dose expected to be delivered to the detectors. Each PSD acquired data in 10 second intervals for the duration of the treatment. The deviation between expected and measured cumulative dose was calculated for each detector for each fraction, and averaged over each patient and the patient population as a whole. Results: The average difference between expected dose and measured dose ranged from -3.3% to 3.3% for individual patients, with standard deviations between 5.6% and 7.1% for four of the patients. The average difference for the entire population was -0.4% with a standard deviation of 2.8%. The detectors were well tolerated by the patients and the system did not interrupt the clinical workflow. Conclusion: PSDs perform well as in vivo dosimeters, exhibiting good accuracy and precision. This, combined with the practicability of using such a system, positions the PSD as a strong candidate for clinical in vivo dosimetry in the future. This work supported in part by the National Cancer Institute through an R01 grant (CA120198

  3. Development of intrinsic IPT scintillator

    SciTech Connect

    Bross, A.D.

    1989-07-31

    We report on the development of a new polystyrene based plastic scintillator. Optical absorption, fluorescence and light output measurements are presented. Preliminary results of radiation damage effects are also given and compared to the effects on a commercial plastic scintillator, NE 110. 6 refs., 12 figs.

  4. Technical Note: Removing the stem effect when performing Ir-192 HDR brachytherapy in vivo dosimetry using plastic scintillation detectors: A relevant and necessary step

    PubMed Central

    Therriault-Proulx, Francois; Beddar, Sam; Briere, Tina M.; Archambault, Louis; Beaulieu, Luc

    2011-01-01

    Purpose: The purpose of this study was to investigate whether or not a stem effect removal technique is necessary when performing Ir-192 HDR brachytherapy in vivo dosimetry using a scintillation detector. Methods: A red-green-blue photodiode connected to a multichannel electrometer was used to detect the light emitted from a plastic scintillation detector (PSD) during irradiation with an Ir-192 HDR brachytherapy source. Accuracy in dose measurement was compared with and without the use of stem effect removal techniques. Monochromatic and polychromatic filtration techniques were studied. An in-house template was built for accurate positioning of catheters in which the source and the PSD were inserted. Dose distribution was measured up to 5 cm from source to detector in the radial and longitudinal directions. Results: The authors found the stem effect to be particularly important when the source was close to the optical fiber guide and far from the scintillation component of the detector. It can account for up to (72±3)% of the signal under clinically relevant conditions. The polychromatic filtration outperformed the monochromatic filtration as well as the absence of filtration in regard to dose measurement accuracy. Conclusions: It is necessary to implement a stem effect removal technique when building a PSD for in vivo dosimetry during Ir-192 HDR brachytherapy. The PSD that the authors have developed for this study would be suitable for such an application. PMID:21626951

  5. The First Tests of a Large-Area Light Detector Equipped with Metallic Magnetic Calorimeters for Scintillating Bolometers for the LUMINEU Neutrinoless Double Beta Decay Search

    NASA Astrophysics Data System (ADS)

    Gray, D.; Enss, C.; Fleischmann, A.; Gastaldo, L.; Hassel, C.; Hengstler, D.; Kempf, S.; Loidl, M.; Navick, X. F.; Rodrigues, M.

    2016-08-01

    Future rare-event searches using scintillating crystals need very low background levels for high sensitivity; however, unresolved pile-up can limit this. We present the design and fabrication of large-area photon detectors based on metallic magnetic calorimeters (MMCs), optimized for fast rise times to resolve close pile-up. The first prototypes have been characterized using Fe-55 X-rays and ZnMoO4 crystal scintillation light. A fast intrinsic rise time of 25-30 \\upmu s has been measured and has been compared to the 250 \\upmu s scintillation light pulse rise time constant. The difference indicates that the scintillation process limits the light pulse rise time. The fast rise time allows for a reduction of background due to close pile-up events as well as the study of the inherent crystal scintillation process. MMC-based photon detectors are shown to be a promising tool for scintillating crystal based rare event searches.

  6. SU-F-BRE-07: Experimental Validation of a Lung SBRT Technique Using a Novel, True Volumetric Plenoptic-Plastic-Scintillator Detector

    SciTech Connect

    Goulet, M; Rilling, M; Gingras, L; Beaulieu, L; Archambault, L; Beddar, S

    2014-06-15

    Purpose: Lung SBRT is being used by an increasing number of clinics, including our center which recently treated its first patient. In order to validate this technique, the 3D dose distribution of the SBRT plan was measured using a previously developed 3D detector based on plenoptic camera and plastic scintillator technology. The excellent agreement between the detector measurement and the expected dose from the treatment planning system Pinnacle{sup 3} shows great promise and amply justify the development of the technique. Methods: The SBRT treatment comprised 8 non-coplanar 6MV photon fields with a mean field size of 12 cm{sup 2} at isocentre and a total prescription dose of 12Gy per fraction for a total of 48Gy. The 3D detector was composed of a 10×10×10 cm{sup 2} EJ-260 water-equivalent plastic scintillator embedded inside a truncated cylindrical acrylic phantom of 10cm radius. The scintillation light was recorded using a static R5 light-field camera and the 3D dose was reconstructed at a 2mm resolution in all 3 dimensions using an iterative backprojection algorithm. Results: The whole 3D dose distribution was recorded at a rate of one acquisition per second. The mean absolute dose difference between the detector and Pinnacle{sup 3} was 1.3% over the region with more than 10% of the maximum dose. 3D gamma tests performed over the same region yield passing rates of 98.8% and 96.6% with criteria of 3%/1mm and 2%/1mm, respectively. Conclusion: Experimental results showed that our beam modeling and treatment planning system calculation was adequate for the safe administration of small field/high dose techniques such as SBRT. Moreover, because of the real-time capability of the detector, further validation of small field rotational, dynamic or gated technique can be monitored or verified by this system.

  7. Pulse shape discrimination properties of plastic scintillators incorporating a rationally designed highly soluble and polymerizable derivative of 9,10-diphenylanthracene

    NASA Astrophysics Data System (ADS)

    Hajagos, Tibor Jacob; Kishpaugh, David; Pei, Qibing

    2016-07-01

    A highly soluble and polymerizable derivative of 9,10-diphenylanthracene was designed and synthesized specifically to be capable of achieving very high loadings (at least 50 wt.%) when copolymerized with a polyvinyltoluene (PVT) matrix. The resulting heavily crosslinked plastics are mechanically hard and robust, and were found to have exceptional clarity with no sign of dye precipitation. Samples of these plastics both with and without added wavelength shifter were characterized for light yield, scintillation decay, and pulse shape discrimination (PSD) performance for α / γ discrimination, and the results were compared to that of a commercially available PSD plastic, EJ-299-34. The best performing formulation, with a primary dye loading of 50 wt.%, had a measured light yield of 9950 photons/MeV, and achieved a PSD figure-of-merit (FOM) of 1.05, the latter indicating that while the present material is not suited for practical applications, the overall approach demonstrates a proof-of-concept of PSD in highly loaded plastics stabilized through copolymerization of the primary dye, and suggests that further improvements through better dye choice/design may yet be achievable.

  8. Spectral method for the correction of the Cerenkov light effect in plastic scintillation detectors: A comparison study of calibration procedures and validation in Cerenkov light-dominated situations

    PubMed Central

    Guillot, Mathieu; Gingras, Luc; Archambault, Louis; Beddar, Sam; Beaulieu, Luc

    2011-01-01

    Purpose: The purposes of this work were: (1) To determine if a spectral method can accurately correct the Cerenkov light effect in plastic scintillation detectors (PSDs) for situations where the Cerenkov light is dominant over the scintillation light and (2) to develop a procedural guideline for accurately determining the calibration factors of PSDs. Methods: The authors demonstrate, by using the equations of the spectral method, that the condition for accurately correcting the effect of Cerenkov light is that the ratio of the two calibration factors must be equal to the ratio of the Cerenkov light measured within the two different spectral regions used for analysis. Based on this proof, the authors propose two new procedures to determine the calibration factors of PSDs, which were designed to respect this condition. A PSD that consists of a cylindrical polystyrene scintillating fiber (1.6 mm3) coupled to a plastic optical fiber was calibrated by using these new procedures and the two reference procedures described in the literature. To validate the extracted calibration factors, relative dose profiles and output factors for a 6 MV photon beam from a medical linac were measured with the PSD and an ionization chamber. Emphasis was placed on situations where the Cerenkov light is dominant over the scintillation light and on situations dissimilar to the calibration conditions. Results: The authors found that the accuracy of the spectral method depends on the procedure used to determine the calibration factors of the PSD and on the attenuation properties of the optical fiber used. The results from the relative dose profile measurements showed that the spectral method can correct the Cerenkov light effect with an accuracy level of 1%. The results obtained also indicate that PSDs measure output factors that are lower than those measured with ionization chambers for square field sizes larger than 25×25 cm2, in general agreement with previously published Monte Carlo

  9. Enhanced light extraction of scintillator using large-area photonic crystal structures fabricated by soft-X-ray interference lithography

    SciTech Connect

    Zhu, Zhichao; Wu, Shuang; Liu, Bo Cheng, Chuanwei; Gu, Mu; Chen, Hong; Xue, Chaofan; Zhao, Jun; Wang, Liansheng; Wu, Yanqing; Tai, Renzhong

    2015-06-15

    Soft-X-ray interference lithography is utilized in combination with atomic layer deposition to prepare photonic crystal structures on the surface of Bi{sub 4}Ge{sub 3}O{sub 12} (BGO) scintillator in order to extract the light otherwise trapped in the internal of scintillator due to total internal reflection. An enhancement with wavelength- and emergence angle-integration by 95.1% has been achieved. This method is advantageous to fabricate photonic crystal structures with large-area and high-index-contrast which enable a high-efficient coupling of evanescent field and the photonic crystal structures. Generally, the method demonstrated in this work is also suitable for many other light emitting devices where a large-area is required in the practical applications.

  10. Silicon photomultiplier readout of a monolithic 270×5×5 cm3 plastic scintillator bar for time of flight applications

    NASA Astrophysics Data System (ADS)

    Reinhardt, Tobias P.; Gohl, Stefan; Reinicke, Stefan; Bemmerer, Daniel; Cowan, Thomas E.; Heidel, Klaus; Röder, Marko; Stach, Daniel; Wagner, Andreas; Weinberger, David; Zuber, Kai

    2016-04-01

    The detection of 200-1000 MeV neutrons requires large amounts, ~ 100 cm, of detector material because of the long nuclear interaction length of these particles. In the example of the NeuLAND neutron time-of-flight detector at FAIR, this is accomplished by using 3000 monolithic scintillator bars of 270 × 5 × 5cm3 size made of a fast plastic. Each bar is read out on the two long ends, and the needed time resolution of σt < 150 ps is reached with fast timing photomultipliers. In the present work, it is investigated whether silicon photomultiplier (SiPM) photosensors can be used instead. Experiments with a picosecond laser system were conducted to determine the timing response of the assembly made up of SiPM and preamplifier. The response of the full system including also the scintillator was studied using 30 MeV single electrons provided by the ELBE superconducting electron linac. The ELBE data were matched by a simple Monte Carlo simulation, and they were found to obey an inverse-square-root scaling law. In the electron beam tests, a time resolution of σt = 136 ps was reached with a pure SiPM readout, well within the design parameters for NeuLAND.

  11. Light output function and assembly of the time-of-flight enhanced diagnostics neutron spectrometer plastic scintillators for background reduction by double kinematic selection at EAST.

    PubMed

    Peng, X Y; Chen, Z J; Zhang, X; Hu, Z M; Du, T F; Cui, Z Q; Xie, X F; Ge, L J; Yuan, X; Gorini, G; Nocente, M; Tardocchi, M; Hu, L Q; Zhong, G Q; Lin, S Y; Wan, B N; Li, X Q; Zhang, G H; Chen, J X; Fan, T S

    2014-11-01

    The 2.5 MeV neutron spectrometer TOFED (Time-Of-Flight Enhanced Diagnostics) has been constructed to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas on EAST. The instrument has a double-ring structure which, in combination with pulse shape digitization, allows for a dual kinematic selection in the time-of-flight/recoil proton energy (tof/Ep) space, thus improving the spectrometer capability to resolve fast ion signatures in the neutron spectrum, in principle up to a factor ≈100. The identification and separation of features from the energetic ions in the neutron spectrum depends on the detailed knowledge of the instrument response function, both in terms of the light output function of the scintillators and the effect of undesired multiple neutron scatterings in the instrument. This work presents the determination of the light output function of the TOFED plastic scintillator detectors and their geometrical assembly. Results from dedicated experiments with γ-ray sources and quasi-monoenergetic neutron beams are presented. Implications on the instrument capability to perform background suppression based on double kinematic selection are discussed. PMID:25430291

  12. Light output function and assembly of the time-of-flight enhanced diagnostics neutron spectrometer plastic scintillators for background reduction by double kinematic selection at EAST

    SciTech Connect

    Peng, X. Y.; Chen, Z. J.; Zhang, X.; Hu, Z. M.; Du, T. F.; Cui, Z. Q.; Xie, X. F.; Ge, L. J.; Yuan, X.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S.; Gorini, G.; Nocente, M.; Tardocchi, M.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.

    2014-11-15

    The 2.5 MeV neutron spectrometer TOFED (Time-Of-Flight Enhanced Diagnostics) has been constructed to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas on EAST. The instrument has a double-ring structure which, in combination with pulse shape digitization, allows for a dual kinematic selection in the time-of-flight/recoil proton energy (tof/E{sub p}) space, thus improving the spectrometer capability to resolve fast ion signatures in the neutron spectrum, in principle up to a factor ≈100. The identification and separation of features from the energetic ions in the neutron spectrum depends on the detailed knowledge of the instrument response function, both in terms of the light output function of the scintillators and the effect of undesired multiple neutron scatterings in the instrument. This work presents the determination of the light output function of the TOFED plastic scintillator detectors and their geometrical assembly. Results from dedicated experiments with γ-ray sources and quasi-monoenergetic neutron beams are presented. Implications on the instrument capability to perform background suppression based on double kinematic selection are discussed.

  13. Optimisation of the imaging and dosimetric characteristics of an electronic portal imaging device employing plastic scintillating fibres using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Blake, S. J.; McNamara, A. L.; Vial, P.; Holloway, L.; Kuncic, Z.

    2014-11-01

    A Monte Carlo model of a novel electronic portal imaging device (EPID) has been developed using Geant4 and its performance for imaging and dosimetry applications in radiotherapy has been characterised. The EPID geometry is based on a physical prototype under ongoing investigation and comprises an array of plastic scintillating fibres in place of the metal plate/phosphor screen in standard EPIDs. Geometrical and optical transport parameters were varied to investigate their impact on imaging and dosimetry performance. Detection efficiency was most sensitive to variations in fibre length, achieving a peak value of 36% at 50 mm using 400 keV x-rays for the lengths considered. Increases in efficiency for longer fibres were partially offset by reductions in sensitivity. Removing the extra-mural absorber surrounding individual fibres severely decreased the modulation transfer function (MTF), highlighting its importance in maximising spatial resolution. Field size response and relative dose profile simulations demonstrated a water-equivalent dose response and thus the prototype’s suitability for dosimetry applications. Element-to-element mismatch between scintillating fibres and underlying photodiode pixels resulted in a reduced MTF for high spatial frequencies and quasi-periodic variations in dose profile response. This effect is eliminated when fibres are precisely matched to underlying pixels. Simulations strongly suggest that with further optimisation, this prototype EPID may be capable of simultaneous imaging and dosimetry in radiotherapy.

  14. Study of equatorial scintillations

    NASA Technical Reports Server (NTRS)

    Pomalaza, J.; Woodman, R.; Tisnado, G.; Nakasone, E.

    1972-01-01

    Observations of the amplitude scintillations produced by the F-region in equatorial areas are presented. The equipment used for conducting the observations is described. The use of transmissions from the ATS-1, ATS-3, and ATS-5 for obtaining data is described. The two principal subjects discussed are: (1) correlation between satellite and incoherent radar observations of scintillations and (2) simultaneous observations of scintillations at 136 MHz and 1550 MHz.

  15. Scintillation detector for carbon-14

    NASA Technical Reports Server (NTRS)

    Knoll, G. F.; Rogers, W. L.

    1971-01-01

    Detector consists of plastic, cylindrical double-wall scintillation cell, which is filled with gas to be analyzed. Thin, inner cell wall is isolated optically from outer (guard) scintillator wall by evaporated-aluminum coating. Bonding technique provides mechanical support to cell wall when device is exposed to high temperatures.

  16. Optimization of light yield by injecting an optical filler into the co-extruded hole of the plastic scintillation bar

    NASA Astrophysics Data System (ADS)

    Artikov, A.; Baranov, V.; Budagov, Ju.; Chokheli, D.; Davydov, Yu.; Glagolev, V.; Kharzheev, Yu.; Kolomoetz, V.; Shalugin, A.; Simonenko, A.; Tereshchenko, V.

    2016-05-01

    The light yield of 2-m long extruded scintillation bars (strips) are measured with cosmic muons as a function of the distance for different options of the light collection technique. The strips with a 2.6-mm diameter central co-extruded hole were made of polystyrene with the 2% PTP and 0.03% POPOP dopants at ISMA (Kharkov, Ukraine). It is shown that the optical transparent BC-600 or CKTN-MED(E) resin injected by a special technique into the co-extruded hole with a 1.0-mm or 1.2-mm Kuraray Y11 (200) MC wave-length shifting (WLS) fiber in it improves light collection by a factor of 1.6–1.9 against the ``dry'' case.

  17. Testing Scintillators for Homeland Security

    NASA Astrophysics Data System (ADS)

    Bourbeau, James; Brandt, Andrew; Kenarangui, Rasool; Weiss, Alex; Chen, Wei

    2011-10-01

    Scintillating nanoparticles have a bright future in radiation detection, especially in the area of detecting nuclear devices. As part of a UTA nanoparticle scintillator development team funded by the Department of Homeland Security, I have been developing a scintillator test stand using various radioactive sources and a Hamamatsu S3590 photodiode. I will present initial test results.

  18. Polysiloxane scintillator composition

    DOEpatents

    Walker, J.K.

    1992-05-05

    A plastic scintillator useful for detecting ionizing radiation comprising a matrix which comprises an optically transparent polysiloxane having incorporated therein at least one ionizing radiation-hard fluor capable of converting electromagnetic energy produced in the polysiloxane upon absorption of ionizing radiation to detectable light.

  19. Polysiloxane scintillator composition

    DOEpatents

    Walker, James K.

    1992-01-01

    A plastic scintillator useful for detecting ionizing radiation comprising a matrix which comprises an optically transparent polysiloxane having incorporated therein at least one ionizing radiation-hard fluor capable of converting electromagnetic energy produced in the polysiloxane upon absorption of ionizing radiation to detectable light.

  20. A phantom study of an in vivo dosimetry system using plastic scintillation detectors for real-time verification of 192Ir HDR brachytherapy

    PubMed Central

    Therriault-Proulx, Francois; Briere, Tina M.; Mourtada, Firas; Aubin, Sylviane; Beddar, Sam; Beaulieu, Luc

    2011-01-01

    Purpose: The goal of the present work was to evaluate the accuracy of a plastic scintillation detector (PSD) system to perform in-phantom dosimetry during 192Ir high dose rate (HDR) brachytherapy treatments. Methods: A PSD system capable of stem effect removal was built. A red–green–blue photodiode connected to a dual-channel electrometer was used to detect the scintillation light emitted from a green scintillation component and transmitted along a plastic optical fiber. A clinically relevant prostate treatment plan was built using the HDR brachytherapy treatment planning system. An in-house fabricated template was used for accurate positioning of the catheters, and treatment delivery was performed in a water phantom. Eleven catheters were inserted and used for dose delivery from 192Ir radioactive source, while two others were used to mimic dosimetry at the rectum wall and in the urethra using a PSD. The measured dose and dose rate data were compared to the expected values from the planning system. The importance of removing stem effects from in vivo dosimetry using a PSD during 192Ir HDR brachytherapy treatments was assessed. Applications for dwell position error detection and temporal verification of the treatment delivery were also investigated. Results: In-phantom dosimetry measurements of the treatment plan led to a ratio to the expected dose of 1.003 ± 0.004 with the PSD at different positions in the urethra and 1.043 ± 0.003 with the PSD inserted in the rectum. Verification for the urethra of dose delivered within each catheter and at specific dwell positions led to average measured to expected ratios of 1.015 ± 0.019 and 1.014 ± 0.020, respectively. These values at the rectum wall were 1.059 ± 0.045 within each catheter and 1.025 ± 0.028 for specific dwell positions. The ability to detect positioning errors of the source depended of the tolerance on the difference to the expected value. A 5-mm displacement of the source was

  1. Extruded scintillator for the Calorimetry applications

    SciTech Connect

    Dyshkant, A.; Rykalin, V.; Pla-Dalmau, A.; Beznosko, D.

    2006-10-27

    An extrusion line has been installed and successfully operated at FNAL (Fermi National Accelerator Laboratory) in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new Facility will serve to further develop and improve extruded plastic scintillator. Recently progress has been made in producing co-extruded plastic scintillator, thus increasing the potential HEP applications of this Facility. The current R and D work with extruded and co-extruded plastic scintillator for a potential ALICE upgrade, the ILC calorimetry program and the MINERvA experiment show the attractiveness of the chosen strategy for future experiments and calorimetry. We extensively discuss extruded and co-extruded plastic scintillator in calorimetry in synergy with new Solid State Photomultipliers. The characteristics of extruded and co-extruded plastic scintillator will be presented here as well as results with non-traditional photo read-out.

  2. Extruded scintillator for the calorimetry applications

    SciTech Connect

    Dyshkant, A.; Rykalin, V.; Pla-Dalmau, A.; Beznosko, D.; /SUNY, Stony Brook

    2006-08-01

    An extrusion line has been installed and successfully operated at FNAL (Fermi National Accelerator Laboratory) in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new Facility will serve to further develop and improve extruded plastic scintillator. Recently progress has been made in producing co-extruded plastic scintillator, thus increasing the potential HEP applications of this Facility. The current R&D work with extruded and co-extruded plastic scintillator for a potential ALICE upgrade, the ILC calorimetry program and the MINERvA experiment show the attractiveness of the chosen strategy for future experiments and calorimetry. We extensively discuss extruded and co-extruded plastic scintillator in calorimetry in synergy with new Solid State Photomultipliers. The characteristics of extruded and co-extruded plastic scintillator will be presented here as well as results with non-traditional photo read-out.

  3. Characterization of Final State Interaction Strength in Plastic Scintillator by Muon-Neutrino Charged Current Charged Pion Production

    SciTech Connect

    Eberly, Brandon M.

    2014-01-01

    Precise knowledge of neutrino-nucleus interactions is increasingly important as neutrino oscillation measurements transition into the systematics-limited era. In addition to modifying the initial interaction, the nuclear medium can scatter and absorb the interaction by-products through final state interactions, changing the types and kinematic distributions of particles seen by the detector. Recent neutrino pion production data from MiniBooNE is inconsistent with the final state interaction strength predicted by models and theoretical calculations, and some models fit best to the MiniBooNE data only after removing final state interactions entirely. This thesis presents a measurement of dσ/dTπ and dσ/dθπ for muon-neutrino charged current charged pion production in the MINER A scintillator tracker. MINER A is a neutrino-nucleus scattering experiment installed in the few-GeV NuMI beam line at Fermilab. The analysis is limited to neutrino energies between 1.5-10 GeV. Dependence on invariant hadronic mass W is studied through two versions of the analysis that impose the limits W < 1.4 GeV and W < 1.8 GeV. The lower limit on W increases compatibility with the MiniBooNE pion data. The shapes of the differential cross sections, which depend strongly on the nature of final state interactions, are compared to Monte Carlo and theoretical predictions. It is shown that the measurements presented in this thesis favor models that contain final state interactions. Additionally, a variety of neutrino-nucleus interaction models are shown to successfully reproduce the thesis measurements, while simultaneously failing to describe the shape of the MiniBooNE data.

  4. A novel fast-neutron tomography system based on a plastic scintillator array and a compact D-D neutron generator.

    PubMed

    Adams, Robert; Zboray, Robert; Prasser, Horst-Michael

    2016-01-01

    Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D-T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D-D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a discussion

  5. A novel fast-neutron tomography system based on a plastic scintillator array and a compact D-D neutron generator.

    PubMed

    Adams, Robert; Zboray, Robert; Prasser, Horst-Michael

    2016-01-01

    Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D-T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D-D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a discussion

  6. Facial plastic surgery area acquisition method based on point cloud mathematical model solution.

    PubMed

    Li, Xuwu; Liu, Fei

    2013-09-01

    It is one of the hot research problems nowadays to find a quick and accurate method of acquiring the facial plastic surgery area to provide sufficient but irredundant autologous or in vitro skin source for covering extensive wound, trauma, and burnt area. At present, the acquisition of facial plastic surgery area mainly includes model laser scanning, point cloud data acquisition, pretreatment of point cloud data, three-dimensional model reconstruction, and computation of area. By using this method, the area can be computed accurately, but it is hard to control the random error, and it requires a comparatively longer computation period. In this article, a facial plastic surgery area acquisition method based on point cloud mathematical model solution is proposed. This method applies symmetric treatment to the point cloud based on the pretreatment of point cloud data, through which the comparison diagram color difference map of point cloud error before and after symmetry is obtained. The slicing mathematical model of facial plastic area is got through color difference map diagram. By solving the point cloud data in this area directly, the facial plastic area is acquired. The point cloud data are directly operated in this method, which can accurately and efficiently complete the surgery area computation. The result of the comparative analysis shows the method is effective in facial plastic surgery area.

  7. Joint measurement of the atmospheric muon flux through the Puy de Dome volcano with plastic scintillators and Resistive Plate Chambers detectors

    DOE PAGES

    Ambrosino, F.; Anastasio, A.; Bross, A.; Bene, S.; Boivin, P.; Bonechi, L.; Carloganu, C.; Ciaranfi, R.; Cimmino, L.; Combaret, Ch.; et al

    2015-11-14

    The muographic imaging of volcanoes relies on the measured transmittance of the atmospheric muon flux through the target. An important bias affecting the result comes from background contamination mimicking a higher transmittance. The MU-RAY and TOMUVOL collaborations measured independently in 2013 the atmospheric muon flux transmitted through the Puy de Dôme volcano using their early prototype detectors, based on plastic scintillators and on Glass Resistive Plate Chambers, respectively. These detectors had three (MU-RAY) or four (TOMUVOL) detection layers of 1 m2 each, tens (MU-RAY) or hundreds (TOMUVOL) of nanosecond time resolution, a few millimeter position resolution, an energy threshold ofmore » few hundreds MeV, and no particle identification capabilities. The prototypes were deployed about 1.3 km away from the summit, where they measured, behind rock depths larger than 1000 m, remnant fluxes of 1.83±0.50(syst)±0.07(stat) m–2 d–1 deg–2 (MU-RAY) and 1.95±0.16(syst)±0.05(stat) m–2 d–1 deg–2 (TOMUVOL), that roughly correspond to the expected flux of high-energy atmospheric muons crossing 600 meters water equivalent (mwe) at 18° elevation. This implies that imaging depths larger than 500 mwe from 1 km away using such prototype detectors suffer from an overwhelming background. These measurements confirm that a new generation of detectors with higher momentum threshold, time-of-flight measurement, and/or particle identification is needed. As a result, the MU-RAY and TOMUVOL collaborations expect shortly to operate improved detectors, suitable for a robust muographic imaging of kilometer-scale volcanoes.« less

  8. Joint measurement of the atmospheric muon flux through the Puy de Dome volcano with plastic scintillators and Resistive Plate Chambers detectors

    SciTech Connect

    Ambrosino, F.; Anastasio, A.; Bross, A.; Bene, S.; Bonechi, L.; Carloganu, C.; Cimmino, L.; Combaret, Ch.; Durand, S.; Fehr, F.; Gailler, L.; Labazuy, Ph.; Laktineh, I.; Masone, V.; Miallier, D.; Mori, N.; Niess, V.; Pla-Dalmau, A.; Portal, A.; Rubinov, P.; Saracino, G.; Scarlini, E.; Strolin, P.; Vulpescu, B.

    2015-11-14

    The muographic imaging of volcanoes relies on the measured transmittance of the atmospheric muon flux through the target. An important bias affecting the result comes from background contamination mimicking a higher transmittance. The MU-RAY and TOMUVOL collaborations measured independently in 2013 the atmospheric muon flux transmitted through the Puy de Dôme volcano using their early prototype detectors, based on plastic scintillators and on Glass Resistive Plate Chambers, respectively. These detectors had three (MU-RAY) or four (TOMUVOL) detection layers of 1 m2 each, tens (MU-RAY) or hundreds (TOMUVOL) of nanosecond time resolution, a few millimeter position resolution, an energy threshold of few hundreds MeV, and no particle identification capabilities. The prototypes were deployed about 1.3 km away from the summit, where they measured, behind rock depths larger than 1000 m, remnant fluxes of 1.83±0.50(syst)±0.07(stat) m–2 d–1 deg–2 (MU-RAY) and 1.95±0.16(syst)±0.05(stat) m–2 d–1 deg–2 (TOMUVOL), that roughly correspond to the expected flux of high-energy atmospheric muons crossing 600 meters water equivalent (mwe) at 18° elevation. This implies that imaging depths larger than 500 mwe from 1 km away using such prototype detectors suffer from an overwhelming background. These measurements confirm that a new generation of detectors with higher momentum threshold, time-of-flight measurement, and/or particle identification is needed. As a result, the MU-RAY and TOMUVOL collaborations expect shortly to operate improved detectors, suitable for a robust muographic imaging of kilometer-scale volcanoes.

  9. Sci—Sat AM: Stereo — 07: Suitability of a plastic scintillator dosimeter for composite clinical fields delivered using the Cyberknife robotic radiosurgery system

    SciTech Connect

    Vandervoort, E.; Szanto, J.; Christiansen, E.

    2014-08-15

    Plastic scintillation dosimeters (PSDs) have favourable characteristics for small and composite field dosimetry in radiosurgery, however, imperfect corrections for the Cerenkov radiation contamination could limit their accuracy for complex deliveries. In this work, we characterize the dose and dose-rate linearity, directional dependence, and compare output factors with other stereotactic detectors for a new commercially available PSD (Exradin W1). We provide some preliminary comparisons of planned and measured dose for composite fields delivered clinically by a Cyberknife radiosurgery system. The W1 detector shows good linearity with dose (<0.5%) and dose rate (<0.8%) relative to the signal obtained using an ion chamber under the same conditions. A maximum difference of 2% was observed depending on the detector's angular orientation. Output factors for all detectors agree within a range of ±3.2% and ±1.5% for the 5 and 7.5 mm collimators, respectively, provided Monte-Carlo corrections for detector effects are applied to diode and ion chambers (without corrections the range is ±5.5% and ±3.1% for these two collimators). For clinical beam deliveries using 5 and 7.5 mm collimators, four of the six patients showed better agreement with planned dose for the PSD detector compared to a micro ion chamber. Two of the six patients investigated, however, showed 5% differences between PSD and planned dose, film measurements and the ratio of PSD and micro ion chamber signal suggest that further investigation is warranted for these plans. The W1 detector is a promising tool for stereotactic plan verification under the challenging dosimetric conditions of stereotactic radiosurgery.

  10. Joint measurement of the atmospheric muon flux through the Puy de Dôme volcano with plastic scintillators and Resistive Plate Chambers detectors

    NASA Astrophysics Data System (ADS)

    Ambrosino, F.; Anastasio, A.; Bross, A.; Béné, S.; Boivin, P.; Bonechi, L.; Cârloganu, C.; Ciaranfi, R.; Cimmino, L.; Combaret, Ch.; D'Alessandro, R.; Durand, S.; Fehr, F.; Français, V.; Garufi, F.; Gailler, L.; Labazuy, Ph.; Laktineh, I.; Lénat, J.-F.; Masone, V.; Miallier, D.; Mirabito, L.; Morel, L.; Mori, N.; Niess, V.; Noli, P.; Pla-Dalmau, A.; Portal, A.; Rubinov, P.; Saracino, G.; Scarlini, E.; Strolin, P.; Vulpescu, B.

    2015-11-01

    The muographic imaging of volcanoes relies on the measured transmittance of the atmospheric muon flux through the target. An important bias affecting the result comes from background contamination mimicking a higher transmittance. The MU-RAY and TOMUVOL collaborations measured independently in 2013 the atmospheric muon flux transmitted through the Puy de Dôme volcano using their early prototype detectors, based on plastic scintillators and on Glass Resistive Plate Chambers, respectively. These detectors had three (MU-RAY) or four (TOMUVOL) detection layers of 1 m2 each, tens (MU-RAY) or hundreds (TOMUVOL) of nanosecond time resolution, a few millimeter position resolution, an energy threshold of few hundreds MeV, and no particle identification capabilities. The prototypes were deployed about 1.3 km away from the summit, where they measured, behind rock depths larger than 1000 m, remnant fluxes of 1.83±0.50(syst)±0.07(stat) m-2 d-1 deg-2 (MU-RAY) and 1.95±0.16(syst)±0.05(stat) m-2 d-1 deg-2 (TOMUVOL), that roughly correspond to the expected flux of high-energy atmospheric muons crossing 600 meters water equivalent (mwe) at 18° elevation. This implies that imaging depths larger than 500 mwe from 1 km away using such prototype detectors suffer from an overwhelming background. These measurements confirm that a new generation of detectors with higher momentum threshold, time-of-flight measurement, and/or particle identification is needed. The MU-RAY and TOMUVOL collaborations expect shortly to operate improved detectors, suitable for a robust muographic imaging of kilometer-scale volcanoes.

  11. Scintillator material

    DOEpatents

    Anderson, David F.; Kross, Brian J.

    1994-01-01

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography.

  12. Scintillator material

    DOEpatents

    Anderson, David F.; Kross, Brian J.

    1992-01-01

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography.

  13. Scintillator material

    DOEpatents

    Anderson, D.F.; Kross, B.J.

    1994-06-07

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography. 4 figs.

  14. Scintillator material

    DOEpatents

    Anderson, D.F.; Kross, B.J.

    1992-07-28

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography. 4 figs.

  15. Characterization of fluor concentration and geometry in organic scintillators for in situ beta imaging

    SciTech Connect

    Tornai, M.P.; Hoffman, E.J.; MacDonald, L.R.; Levin, C.S.

    1996-12-01

    Development of a small area (1--2 cm{sup 2}) in situ beta imaging device includes optimization of the front end scintillation detector, which is fiber optically coupled to a remote photon detector. Thin plastic scintillation detectors, which are sensitive to charged particles, are the ideal detectors due to the low sensitivity to ambient gamma backgrounds. The light output of a new binary plastic scintillator was investigated with respect to increasing concentrations of the fluor (0.5--2.0% by weight) and varying thickness cylindrical configurations of the intended imaging detector. The fluor had an emission maximum increasing from 431 to 436 nm with increasing fluor concentration. The decay time(s) had two components (0.38 and 1.74 ns). There was an {approximately}20% increase in light output with increasing fluor concentration measured with both {sup 204}Tl betas and conversion electrons from {sup 207}Bi. The highest light output of this new scintillator was measured to be {approximately}30% lower than BC404. Simulations predicted the 1.5 mm scintillator thickness at which light output and energy absorption for {approximately}700 keV electrons (e.g., from {sup 204}Tl, {sup 18}F) were maximized, which corresponded with measurements. As beta continua are relatively featureless, energy calibration for the thin scintillators was investigated using Landau distributions, which appear as distinct peaks in the spectra. As the scintillators were made thinner, gamma backgrounds were shown to linearly decrease.

  16. Young green turtles, Chelonia mydas, exposed to plastic in a frontal area of the SW Atlantic.

    PubMed

    González Carman, Victoria; Acha, E Marcelo; Maxwell, Sara M; Albareda, Diego; Campagna, Claudio; Mianzan, Hermes

    2014-01-15

    Ingestion of anthropogenic debris represents an important threat to marine turtle populations. Information has been limited to inventories of debris ingested and its consequences, but why ingestion occurs and the conditions that enable it are less understood. Here we report on the occurrence of plastic ingestion in young green turtles (Chelonia mydas) inhabiting the Río de la Plata (SW Atlantic). This estuarine area is characterized by a frontal system that accumulates anthropogenic debris. We explored exposure of green turtles to plastic and its ingestion via debris distribution, habitat use and digestive tract examination. Results indicated that there is considerable overlap of frontal accumulated plastic and core foraging areas of the animals. Exposure results in ingestion, as shown by the high frequency of plastic found in the digestive tracts. The Río de la Plata estuarine front is an area of conservation concern for young green turtles.

  17. Young green turtles, Chelonia mydas, exposed to plastic in a frontal area of the SW Atlantic.

    PubMed

    González Carman, Victoria; Acha, E Marcelo; Maxwell, Sara M; Albareda, Diego; Campagna, Claudio; Mianzan, Hermes

    2014-01-15

    Ingestion of anthropogenic debris represents an important threat to marine turtle populations. Information has been limited to inventories of debris ingested and its consequences, but why ingestion occurs and the conditions that enable it are less understood. Here we report on the occurrence of plastic ingestion in young green turtles (Chelonia mydas) inhabiting the Río de la Plata (SW Atlantic). This estuarine area is characterized by a frontal system that accumulates anthropogenic debris. We explored exposure of green turtles to plastic and its ingestion via debris distribution, habitat use and digestive tract examination. Results indicated that there is considerable overlap of frontal accumulated plastic and core foraging areas of the animals. Exposure results in ingestion, as shown by the high frequency of plastic found in the digestive tracts. The Río de la Plata estuarine front is an area of conservation concern for young green turtles. PMID:24315702

  18. Scintillation Counters

    NASA Astrophysics Data System (ADS)

    Bell, Zane W.

    Scintillators find wide use in radiation detection as the detecting medium for gamma/X-rays, and charged and neutral particles. Since the first notice in 1895 by Roentgen of the production of light by X-rays on a barium platinocyanide screen, and Thomas Edison's work over the following 2 years resulting in the discovery of calcium tungstate as a superior fluoroscopy screen, much research and experimentation have been undertaken to discover and elucidate the properties of new scintillators. Scintillators with high density and high atomic number are prized for the detection of gamma rays above 1 MeV; lower atomic number, lower-density materials find use for detecting beta particles and heavy charged particles; hydrogenous scintillators find use in fast-neutron detection; and boron-, lithium-, and gadolinium-containing scintillators are used for slow-neutron detection. This chapter provides the practitioner with an overview of the general characteristics of scintillators, including the variation of probability of interaction with density and atomic number, the characteristics of the light pulse, a list and characteristics of commonly available scintillators and their approximate cost, and recommendations regarding the choice of material for a few specific applications. This chapter does not pretend to present an exhaustive list of scintillators and applications.

  19. New liquid scintillators for fiber-optic applications

    SciTech Connect

    Lutz, S.S.; Franks, L.A.; Flournoy, J.M.; Lyons, P.B.

    1981-01-01

    New long-wavelength-emitting, high-speed, liquid scintillators have been developed and tailored specifically for plasma diagnostic experiments employing fiber optics. These scintillators offer significant advantages over commercially available plastic scintillators in terms of sensitivity and bandwidth. FWHM response times as fast as 350 ps have been measured. Emission spectra, time response data, and relative sensitivity information are presented.

  20. A comparative study of small field total scatter factors and dose profiles using plastic scintillation detectors and other stereotactic dosimeters: The case of the CyberKnife

    SciTech Connect

    Morin, J.; Beliveau-Nadeau, D.; Chung, E.; Seuntjens, J.; Theriault, D.; Archambault, L.; Beddar, S.; Beaulieu, L.

    2013-01-15

    Purpose: Small-field dosimetry is challenging, and the main limitations of most dosimeters are insufficient spatial resolution, water nonequivalence, and energy dependence. The purpose of this study was to compare plastic scintillation detectors (PSDs) to several commercial stereotactic dosimeters by measuring total scatter factors and dose profiles on a CyberKnife system. Methods: Two PSDs were developed, having sensitive volumes of 0.196 and 0.785 mm{sup 3}, and compared with other detectors. The spectral discrimination method was applied to subtract Cerenkov light from the signal. Both PSDs were compared to four commercial stereotactic dosimeters by measuring total scatter factors, namely, an IBA dosimetry stereotactic field diode (SFD), a PTW 60008 silicon diode, a PTW 60012 silicon diode, and a microLion. The measured total scatter factors were further compared with those of two independent Monte Carlo studies. For the dose profiles, two commercial detectors were used for the comparison, i.e., a PTW 60012 silicon diode and Gafchromics EBT2. Total scatter factors for a CyberKnife system were measured in circular fields with diameters from 5 to 60 mm. Dose profiles were measured for the 5- and 60-mm cones. The measurements were performed in a water tank at a 1.5-cm depth and an 80-cm source-axis distance. Results: The total scatter factors measured using all the detectors agreed within 1% with the Monte Carlo values for cones of 20 mm or greater in diameter. For cones of 10-20 mm in diameter, the PTW 60008 silicon diode was the only dosimeter whose measurements did not agree within 1% with the Monte Carlo values. For smaller fields (<10 mm), each dosimeter type showed different behaviors. The silicon diodes over-responded because of their water nonequivalence; the microLion and 1.0-mm PSD under-responded because of a volume-averaging effect; and the 0.5-mm PSD was the only detector within the uncertainties of the Monte Carlo simulations for all the cones. The

  1. Visco-plastic Lubrication: New Areas for Application

    NASA Astrophysics Data System (ADS)

    Hormozi, Sarah; Frigaard, Ian

    2011-11-01

    Stable multi-layer flows can be achieved at high Reynolds numbers by using a yield stress fluids in a lubricating outer layer. These flows have been demonstrated to be linearly and nonlinearly stable as well as observable experimentally; see Frigaard (2001), Moyers-Gonzalez et al. (2004) and Huen et al. (2007). Recently, we have studied these flows computationally in the setting of a Newtonian core fluid surrounded by a Bingham lubricated fluid, within pipe and channel configurations; see Hormozi et al. (2011a) and Hormozi et al. (2011b). The results show that we are able to freeze in non-planar interface and form interesting patterns by retaining an unyielded plug region at the interface. Our studies open up new potential areas for application such as drop encapsulation and near net shape production of multi-layered products with axial variations. We give an overview of experimental results on establishing these exotic patterns.

  2. Polybrominated diphenyl ethers in soils, sediments, and human hair in a plastic waste recycling area: a neglected heavily polluted area.

    PubMed

    Tang, Zhenwu; Huang, Qifei; Cheng, Jiali; Yang, Yufei; Yang, Jun; Guo, Wei; Nie, Zhiqiang; Zeng, Ning; Jin, Lu

    2014-01-01

    The release of pollutants during the recycling of contaminated plastics is a problem which has drawn worldwide attention; however, little information on the transfer of polybrominated diphenyl ethers (PBDEs) in these processes is available. We conducted a survey of PBDEs in soils, sediments, and human hair in a typical plastic waste recycling area in northern China. The total concentrations (ng/g) of 21 PBDEs were 1.25-5504 (average 600), 18.2-9889 (average 1619), and 1.50-861 (average 112) in soils, sediments, and hair, respectively. The PBDE concentrations were comparable to concentrations observed in e-waste recycling areas; however, the concentrations in soils and sediments were 1-3 orders of magnitude higher than in other areas, and the concentrations in hair were much higher than in other areas. This indicates that this area is highly polluted with PBDEs. BDE-209 was the dominant congener (representing 91.23%, 92.3%, and 91.5% of the total PBDEs observed in soils, sediments, and hair, respectively), indicating that the commercial deca-BDE product was dominant. The commercial penta- and octa-BDE products made small contributions to the total PBDE concentrations, unlike what has been found in some e-waste recycling areas. Our results show that crude plastic waste processing is a major contributor of PBDEs to the environment and humans, which should be of great concern.

  3. Synaptic plasticity in the hippocampal area CA1-subiculum projection: implications for theories of memory.

    PubMed

    O'Mara, S M; Commins, S; Anderson, M

    2000-01-01

    This paper reviews investigations of synaptic plasticity in the major, and underexplored, pathway from hippocampal area CA1 to the subiculum. This brain area is the major synaptic relay for the majority of hippocampal area CA1 neurons, making the subiculum the last relay of the hippocampal formation prior to the cortex. The subiculum thus has a very major role in mediating hippocampal-cortical interactions. We demonstrate that the projection from hippocampal area CA1 to the subiculum sustains plasticity on a number of levels. We show that this pathway is capable of undergoing both long-term potentiation (LTP) and paired-pulse facilitation (PPF, a short-term plastic effect). Although we failed to induce long-term depression (LTD) of this pathway with low-frequency stimulation (LFS) and two-pulse stimulation (TPS), both protocols can induce a "late-developing" potentiation of synaptic transmission. We further demonstrate that baseline synaptic transmission can be dissociated from paired-pulse stimulation of the same pathway; we also show that it is possible, using appropriate protocols, to change PPF to paired-pulse depression, thus revealing subtle and previously undescribed mechanisms which regulate short-term synaptic plasticity. Finally, we successfully recorded from individual subicular units in the freely-moving animal, and provide a description of the characteristics of such neurons in a pellet-chasing task. We discuss the implications of these findings in relation to theories of the biological consolidation of memory.

  4. Aging, plasticity and environmental enrichment: structural changes and neurotransmitter dynamics in several areas of the brain.

    PubMed

    Mora, Francisco; Segovia, Gregorio; del Arco, Alberto

    2007-08-01

    Cajal was probably the first neurobiologist to suggest that plasticity of nerve cells almost completely disappeared during aging. However, we know today that neural plasticity is still present in the brain during aging. In this review we suggest that aging is a physiological process that occurs asynchronously in different areas of the brain and that the rate of that process is modulated by environmental factors and related to the neuronal-synaptic-molecular substrates of each area. We review here some of the most recent results on aging of the brain in relation to the plastic changes that occur in young and aged animals as a result of living in an enriched environment. We highlight the results from our own laboratory on the dynamics of neurotransmitters in different areas of the brain. Specifically we review first the effects of aging on neurons, dendrites, synapses, and also on molecular and functional plasticity. Second, the effects of environmental enrichment on the brain of young and aged animals. And third the effects of an enriched environment on the age-related changes in neurogenesis and in the extracellular concentrations of glutamate and GABA in hippocampus, and on dopamine, acetylcholine, glutamate and GABA under a situation of acute mild stress in the prefrontal cortex.

  5. Large area ceramic thin films on plastics: A versatile route via solution processing

    SciTech Connect

    Kozuka, H.; Yamano, A.; Uchiyama, H.; Takahashi, M.; Fukui, T.; Yoki, M.; Akase, T.

    2012-01-01

    A new general route for large area, submicron thick ceramic thin films (crystalline metal oxide thin films) on plastic substrates is presented, where the crystallization of films is guaranteed by a firing process. Gel films are deposited on silicon substrates with a release layer and fired to be ceramic films, followed by transferring onto plastic substrates using adhesives. The ceramic films thus fabricated on plastics exhibit a certain degree of flexibility, implying the possibility of the technique to be applied to high-throughput roll-to-roll processes. Using this technique, we successfully realized transparent anatase thin films that provide high optical reflectance and transparent indium tin oxide thin films that exhibit electrical conductivity on polycarbonate and acrylic resin substrates, respectively. Crystallographically oriented zinc oxide films and patterned zinc oxide films are also demonstrated to be realized on acrylic resin substrates.

  6. Spike timing-dependent plasticity at GABAergic synapses in the ventral tegmental area.

    PubMed

    Kodangattil, Jayaraj N; Dacher, Matthieu; Authement, Michael E; Nugent, Fereshteh S

    2013-10-01

    Persistent changes in excitatory and inhibitory synaptic strengths to the ventral tegmental area (VTA) dopamine (DA) neurons in response to addictive drugs may underlie the transition from casual to compulsive drug use. While an enormous amount of work has been done in the area of glutamatergic plasticity of the VTA, little is known regarding the learning rules governing GABAergic plasticity in the VTA. Spike timing-dependent plasticity, STDP, has attracted considerable attention primarily due to its potential roles in processing and storage of information in the brain and there is emerging evidence for the existence of STDP at inhibitory synapses. We therefore used whole-cell recordings in rat midbrain slices to investigate whether near-coincident pre- and postsynaptic firing induces a lasting change in synaptic efficacy of VTA GABAergic synapses. We found that a Hebbian form of STDP including long-term potentiation (LTP) and long-term depression (LTD) can be induced at GABAergic synapses onto VTA DA neurons and relies on the precise temporal order of pre- and postsynaptic spiking. Importantly, GABAergic STDP is heterosynaptic (NMDA receptor dependent): triggered by correlated activities of the presynaptic glutamatergic input and postsynaptic DA cells. GABAergic STDP is postsynaptic and has an associative component since pre- or postsynaptic spiking per se did not induce STDP. STDP of GABAergic synapses in the VTA provides physiologically relevant forms of inhibitory plasticity that may underlie natural reinforcement of reward-related behaviours. Moreover, this form of inhibitory plasticity may mediate some of the reinforcing, aversive and addictive properties of drugs of abuse.

  7. SCINTILLATION SPECTROMETER

    DOEpatents

    Bell, P.R.; Francis, J.E.

    1960-06-21

    A portable scintillation spectrometer is described which is especially useful in radio-biological studies for determining the uptake and distribution of gamma -emitting substances in tissue. The spectrometer includes a collimator having a plurality of apertures that are hexagonal in cross section. Two crystals are provided: one is activated to respond to incident rays from the collimator; the other is not activated and shields the first from external radiation.

  8. Development of radiation hard scintillators

    SciTech Connect

    Markley, F.; Woods, D.; Pla-Dalmau, A.; Foster, G. ); Blackburn, R. )

    1992-05-01

    Substantial improvements have been made in the radiation hardness of plastic scintillators. Cylinders of scintillating materials 2.2 cm in diameter and 1 cm thick have been exposed to 10 Mrads of gamma rays at a dose rate of 1 Mrad/h in a nitrogen atmosphere. One of the formulations tested showed an immediate decrease in pulse height of only 4% and has remained stable for 12 days while annealing in air. By comparison a commercial PVT scintillator showed an immediate decrease of 58% and after 43 days of annealing in air it improved to a 14% loss. The formulated sample consisted of 70 parts by weight of Dow polystyrene, 30 pbw of pentaphenyltrimethyltrisiloxane (Dow Corning DC 705 oil), 2 pbw of p-terphenyl, 0.2 pbw of tetraphenylbutadiene, and 0.5 pbw of UVASIL299LM from Ferro.

  9. Zero plastics and the radiologically protected area low level waste lockout program. Final report

    SciTech Connect

    Kelly, J.

    1995-11-01

    In 1993, EPRI initiated its Integrated LLW Cost and Volume Reduction Program. One key component of the project was the identification of unique or uncommon techniques and approaches to LLW management which could be transported with or without modification to other members of EPRI`s Nuclear Power Business Group. Included among these unique approaches were: some nuclear stations had aggressively eliminated most of the plastic materials commonly used in radiologically protected areas (RPA), these included plastic bags, plastic sheeting and plastic sleeving; a few nuclear stations had completely eliminated from the RPA some of the disposable items routinely considered by most nuclear stations as absolutely essential, these included masking tape, duct tape and wood; a couple of leading edge plants were implementing RPA LLW lockout programs in an effort to control absolutely all materials entering or exiting the RPA and making the worker 100% responsible for managing her/his work environment. The above three approaches were so significant in their actual or potential impact that it was decided to initiate an independent research project to evaluate and demonstrate whether all three concepts could be implemented by a single nuclear station and with significant, positive results. This project reports on that research and demonstration project which was implemented at LaSalle and Zion nuclear stations, both of which are operated by Commonwealth Edison Company.

  10. Handy Compton camera using 3D position-sensitive scintillators coupled with large-area monolithic MPPC arrays

    NASA Astrophysics Data System (ADS)

    Kataoka, J.; Kishimoto, A.; Nishiyama, T.; Fujita, T.; Takeuchi, K.; Kato, T.; Nakamori, T.; Ohsuka, S.; Nakamura, S.; Hirayanagi, M.; Adachi, S.; Uchiyama, T.; Yamamoto, K.

    2013-12-01

    The release of radioactive isotopes (mainly 137Cs, 134Cs and 131I) from the crippled Fukushima Daiichi Nuclear Plant remains a serious problem in Japan. To help identify radiation hotspots and ensure effective decontamination operation, we are developing a novel Compton camera weighting only 1 kg and measuring just ∼10 cm2 in size. Despite its compactness, the camera realizes a wide 180° field of vision with a sensitivity about 50 times superior to other cameras being tested in Fukushima. We expect that a hotspot producing a 5 μSv/h dose at a distance of 3 m can be imaged every 10 s, with angular resolution better than 10° (FWHM). The 3D position-sensitive scintillators and thin monolithic MPPC arrays are the key technologies developed here. By measuring the pulse-height ratio of MPPC-arrays coupled at both ends of a Ce:GAGG scintillator block, the depth of interaction (DOI) is obtained for incident gamma rays as well as the usual 2D positions, with accuracy better than 2 mm. By using two identical 10 mm cubic Ce:GAGG scintillators as a scatterer and an absorber, we confirmed that the 3D configuration works well as a high-resolution gamma camera, and also works as spectrometer achieving typical energy resolution of 9.8% (FWHM) for 662 keV gamma rays. We present the current status of the prototype camera (weighting 1.5 kg and measuring 8.5×14×16 cm3 in size) being fabricated by Hamamatsu Photonics K.K. Although the camera still operates in non-DOI mode, angular resolution as high as 14° (FWHM) was achieved with an integration time of 30 s for the assumed hotspot described above.

  11. Nanosecond multi-pulse laser milling for certain area removal of metal coating on plastics surface

    NASA Astrophysics Data System (ADS)

    Zhao, Kai; Jia, Zhenyuan; Ma, Jianwei; Liu, Wei; Wang, Ling

    2014-12-01

    Metal coating with functional pattern on engineering plastics surface plays an important role in industry applications; it can be obtained by adding or removing certain area of metal coating on engineering plastics surface. However, the manufacturing requirements are improved continuously and the plastic substrate presents three-dimensional (3D) structure-many of these parts cannot be fabricated by conventional processing methods, and a new manufacturing method is urgently needed. As the laser-processing technology has many advantages like high machining accuracy and constraints free substrate structure, the machining of the parts is studied through removing certain area of metal coating based on the nanosecond multi-pulse laser milling. To improve the edge quality of the functional pattern, generation mechanism and corresponding avoidance strategy of the processing defects are studied. Additionally, a prediction model for the laser ablation depth is proposed, which can effectively avoid the existence of residual metal coating and reduces the damage of substrate. With the optimal machining parameters, an equiangular spiral pattern on copper-clad polyimide (CCPI) is machined based on the laser milling at last. The experimental results indicate that the edge of the pattern is smooth and consistent, the substrate is flat and without damage. The achievements in this study could be applied in industrial production.

  12. Plastic Gamma Sensors: An Application in Detection of Radioisotopes

    SciTech Connect

    S. Mukhopadhyay

    2003-06-01

    A brief survey of plastic scintillators for various radiation measurement applications is presented here. The utility of plastic scintillators for practical applications such as gamma radiation monitoring, real-time radioisotope detection and screening is evaluated in laboratory and field measurements. This study also reports results of Monte Carlo-type predictive responses of common plastic scintillators in gamma and neutron radiation fields. Small-size plastic detectors are evaluated for static and dynamic gamma-ray detection sensitivity of selected radiation sources.

  13. Time and Amplitude Characteristics of Large Scintillation Detectors with SiPM

    NASA Astrophysics Data System (ADS)

    Kaplin, V. A.; Makliaev, E. F.; Melikyan, Yu. A.; Naumov, P. P.; Naumov, P. Yu.; Runtso, M. F.

    A large plastic scintillation detector system with silicon photomultiplier (SiPM) readout has been developed as a prototype for future astroparticle experiments' detectors. A set of SiPM connected in parallel was used in order to enlarge the light collection effective area and thus enhance the detector's amplitude and timing performance. Here we report on the values of time resolution and scintillation detection efficiency of such a system for different types of SiPM as a function of the distance between the scintillation strip edge with photomultipliers attached to it, and the penetrating particle. Results of a special simulation study of the system's amplitude and timing performance as a function of the SiPM radiation aging are also presented.

  14. Microprocessor-based single particle calibration of scintillation counter

    NASA Technical Reports Server (NTRS)

    Mazumdar, G. K. D.; Pathak, K. M.

    1985-01-01

    A microprocessor-base set-up is fabricated and tested for the single particle calibration of the plastic scintillator. The single particle response of the scintillator is digitized by an A/D converter, and a 8085 A based microprocessor stores the pulse heights. The digitized information is printed. Facilities for CRT display and cassette storing and recalling are also made available.

  15. Plastic pollution of the Kuril-Kamchatka Trench area (NW pacific)

    NASA Astrophysics Data System (ADS)

    Fischer, Viola; Elsner, Nikolaus O.; Brenke, Nils; Schwabe, Enrico; Brandt, Angelika

    2015-01-01

    During the German-Russian expedition KuramBio (Kuril-Kamchatka Biodiversity Studies) to the northwest Pacific Kuril-Kamchatka Trench and its adjacent abyssal plain, we found several kinds and sizes of plastic debris ranging from fishing nets and packaging to microplastic in the sediment of the deep-sea floor. Microplastics were ubiquitous in the smaller fractions of the box corer samples from every station from depths between 4869 and 5766 m. They were found on the abyssal plain and in the sediments of the trench slope on both sides. The amount of microplastics differed between the stations, with lowest concentration of 60 pieces per m2 and highest concentrations of more than 2000 pieces per m2. Around 75% of the microplastics (defined here as particles <1 mm) we isolated from the sediment samples were fibers. Other particles were paint chips or small cracked pieces of unknown origin. The Kuril-Kamchatka Trench area is known for its very rich marine fauna (Zenkevich, 1963). Yet we can only guess how these microplastics accumulated in the deep sea of the Kuril-Kamchatka Trench area and what consequences the microplastic itself and its adsorbed chemicals will have on this very special and rich deep-sea fauna. But we herewith present an evaluation of the different kinds of plastic debris we found, as a documentation of human impact into the deep sea of this region of the Northwest Pacific.

  16. A Beta-Particle Hodoscope Constructed Using Scintillating Optical Fibers and Position Sensitive Photomultiplier Tubes

    SciTech Connect

    Orrell, John L.; Aalseth, Craig E.; Day, Anthony R.; Fast, Jim; Hossbach, Todd W.; Lidey, Lance S.; Ripplinger, Mike D.; Schrom, Brian T.

    2006-09-19

    A hodoscopic detector was constructed using a position-sensitive plastic scintillator active area to determine the location of beta-active micron-sized particulates on air filters. The ability to locate beta active particulates on airsample filters is a tool for environmental monitoring of anthropogenic production of radioactive material. A robust, field-deployable instrument can provide localization of radioactive particulate with position resolution of a few millimeters. The detector employs a novel configuration of scintillating plastic elements usually employed at much higher charged particle energies. A filter is placed on this element for assay. The detector is intended to be sensitive to activity greater than 1 Bq. The physical design, position reconstruction method, and expected detector sensitivity are reported.

  17. PREFACE: Applications of Novel Scintillators for Research and Industry (ANSRI 2015)

    NASA Astrophysics Data System (ADS)

    Roberts, O. J.

    2015-06-01

    Scintillator detectors are used widely in the field of γ- and X-ray spectroscopy, particularly in the mid 1900s when the invention of NaI(Tl) by nobel laureate Robert Hofstadter in 1948, spurred the creation of new scintillator materials. In the development of such new scintillators, important characteristics such as its intrinsic efficiency, position sensitivity, robustness, energy and timing response, light output, etc, need to be addressed. To date, these requirements cannot be met by a single type of scintillator alone and therefore the development of an ''ideal'' scintillator remains the holy grail of nuclear instrumentation. Consequently, the last two decades have seen significant progress in the development of scintillator crystals, driven largely by technological advances. Conventional inorganic scintillators such as NaI(Tl) and BGO are now being replaced with better, novel organic, inorganic, ceramic and plastic scintillators offering a wider variety of options for many applications. The workshop on the Applications of Novel Scintillators in Research and Industry was held at University College Dublin in January 2015 and covered a wide range of topics that characterise modern advances in the field of scintillator technology. This set of proceedings covers areas including the growth, production and characterisation of such contemporary scintillators, along with their applications in various fields, such as; Medical Imaging; Defence/Security; Astrophysics; and Nuclear/Particle Physics. We would like to thank all those who presented their recent results on their research at the workshop. These proceedings atest to the excitement and interest in such a broad field, that pervades the pursuit of the development of novel materials for future applications. We would also like to thank Professor Luigi Piro, for giving an interesting public talk during the conference, and to the Institute of Physics Ireland Group for supporting the event. We thank ORTEC for

  18. Patient safety in plastic surgery: identifying areas for quality improvement efforts.

    PubMed

    Hernandez-Boussard, Tina; McDonald, Kathryn M; Rhoads, Kim F; Curtin, Catherine M

    2015-05-01

    Improving quality of health care is a global priority. Before quality benchmarks are established, we first must understand rates of adverse events (AEs). This project assessed risk-adjusted rates of inpatient AEs for soft tissue reconstructive procedures.Patients receiving soft tissue reconstructive procedures from 2005 to 2010 were extracted from the Nationwide Inpatient Sample. Inpatient AEs were identified using patient safety indicators (PSIs), established measures developed by Agency for Healthcare Research and Quality.We identified 409,991 patients with soft tissue reconstruction and 16,635 (4.06%) had a PSI during their hospital stay. Patient safety indicators were associated with increased risk-adjusted mortality, longer length of stay, and decreased routine disposition (P < 0.01). Patient characteristics associated with a higher risk-adjusted rate per 1000 patients at risk included older age, men, nonwhite, and public payer (P < 0.05). Overall, plastic surgery patients had significantly lower risk-adjusted rate compared to other surgical inpatients for all events evaluated except for failure to rescue and postoperative hemorrhage or hematoma, which were not statistically different. Risk-adjusted rates of hematoma hemorrhage were significantly higher in patients receiving size-reduction surgery, and these rates were further accentuated when broken down by sex and payer. In general, plastic surgery patients had lower rates of in-hospital AEs than other surgical disciplines, but PSIs were not uncommon. With the establishment of national basal PSI rates in plastic surgery patients, benchmarks can be devised and target areas for quality improvement efforts identified. Further prospective studies should be designed to elucidate the drivers of AEs identified in this population.

  19. Measurement of transmission efficiency for 400 MeV proton beam through collimator at Fermilab MuCool Test Area using Chromox-6 scintillation screen.

    PubMed

    Jana, M R; Chung, M; Freemire, B; Hanlet, P; Leonova, M; Moretti, A; Palmer, M; Schwarz, T; Tollestrup, A; Torun, Y; Yonehara, K

    2013-06-01

    The MuCool Test Area (MTA) at Fermilab is a facility to develop the technology required for ionization cooling for a future Muon Collider and∕or Neutrino Factory. As part of this research program, feasibility studies of various types of RF cavities in a high magnetic field environment are in progress. As a unique approach, we have tested a RF cavity filled with a high pressure hydrogen gas with a 400 MeV proton beam in an external magnetic field (B = 3 T). Quantitative information about the number of protons passing through this cavity is an essential requirement of the beam test. The MTA is a flammable gas (hydrogen) hazard zone. Due to safety reasons, no active (energized) beam diagnostic instrument can be used. Moreover, when the magnetic field is on, current transformers (toroids) used for beam intensity measurements do not work due to the saturation of the ferrite material of the transformer. Based on these requirements, we have developed a passive beam diagnostic instrumentation using a combination of a Chromox-6 scintillation screen and CCD camera. This paper describes details of the beam profile and position obtained from the CCD image with B = 0 T and B = 3 T, and for high and low intensity proton beams. A comparison is made with beam size obtained from multi-wires detector. Beam transmission efficiency through a collimator with a 4 mm diameter hole is measured by the toroids and CCD image of the scintillation screen. Results show that the transmission efficiency estimated from the CCD image is consistent with the toroid measurement, which enables us to monitor the beam transmission efficiency even in a high magnetic field environment.

  20. Applications for Large Solid Scintillator Detectors in Neutrino and Particle Astrophysics

    NASA Astrophysics Data System (ADS)

    Bross, Alan D.

    2012-08-01

    Applications for solid scintillator have expanded tremendously over the last decade due, in part, to the development of extruded plastic scintillator. In addition, the rapid development of new solid-state photo detectors over the last few years has further expanded the possibilities for this type of detector. This talk will review the state-of-the-art in solid scintillator detectors focusing on applications in neutrino physics, and will present some new possibilities for inorganic scintillator use in particle astrophysics experiments.

  1. FNAL-NICADD extruded scintillator

    SciTech Connect

    Beznosko, D.; Bross, A.; Dyshkant, A.; Pla-Dalmau, A.; Rykalin, V.; /Northern Illinois U.

    2005-09-01

    The possibility to produce a scintillator that satisfies the demands of physicists from different science areas has emerged with the installation of an extrusion line at Fermi National Accelerator Laboratory (FNAL). The extruder is the product of the fruitful collaboration between FNAL and Northern Illinois Center for Accelerator and Detector Development (NICADD) at Northern Illinois University (NIU). The results from the light output, light attenuation length and mechanical tolerance indicate that FNAL-NICADD scintillator is of high quality. Improvements in the extrusion die will yield better scintillator profiles and decrease the time needed for initial tuning. This paper will present the characteristics of the FNAL-NICADD scintillator based on the measurements performed. They include the response to MIPs from cosmic rays for individual extruded strips and irradiation studies where extruded samples were irradiated up to 1 Mrad. We will also discuss the results achieved with a new die design. The attractive perspective of using the extruded scintillator with MRS (Metal Resistive Semiconductor) photodetector readout will also be shown.

  2. Scintillators and applications thereof

    DOEpatents

    Williams, Richard T.

    2015-09-01

    Scintillators of various constructions and methods of making and using the same are provided. In some embodiments, a scintillator comprises at least one radiation absorption region and at least one spatially discrete radiative exciton recombination region.

  3. Scintillators and applications thereof

    DOEpatents

    Williams, Richard T.

    2014-07-15

    Scintillators of various constructions and methods of making and using the same are provided. In some embodiments, a scintillator comprises at least one radiation absorption region and at least one spatially discrete radiative exciton recombination region.

  4. GABAA receptor drugs and neuronal plasticity in reward and aversion: focus on the ventral tegmental area.

    PubMed

    Vashchinkina, Elena; Panhelainen, Anne; Aitta-Aho, Teemu; Korpi, Esa R

    2014-01-01

    GABAA receptors are the main fast inhibitory neurotransmitter receptors in the mammalian brain, and targets for many clinically important drugs widely used in the treatment of anxiety disorders, insomnia and in anesthesia. Nonetheless, there are significant risks associated with the long-term use of these drugs particularly related to development of tolerance and addiction. Addictive mechanisms of GABAA receptor drugs are poorly known, but recent findings suggest that those drugs may induce aberrant neuroadaptations in the brain reward circuitry. Recently, benzodiazepines, acting on synaptic GABAA receptors, and modulators of extrasynaptic GABAA receptors (THIP and neurosteroids) have been found to induce plasticity in the ventral tegmental area (VTA) dopamine neurons and their main target projections. Furthermore, depending whether synaptic or extrasynaptic GABAA receptor populations are activated, the behavioral outcome of repeated administration seems to correlate with rewarding or aversive behavioral responses, respectively. The VTA dopamine neurons project to forebrain centers such as the nucleus accumbens and medial prefrontal cortex, and receive afferent projections from these brain regions and especially from the extended amygdala and lateral habenula, forming the major part of the reward and aversion circuitry. Both synaptic and extrasynaptic GABAA drugs inhibit the VTA GABAergic interneurons, thus activating the VTA DA neurons by disinhibition and this way inducing glutamatergic synaptic plasticity. However, the GABAA drugs failed to alter synaptic spine numbers as studied from Golgi-Cox-stained VTA dendrites. Since the GABAergic drugs are known to depress the brain metabolism and gene expression, their likely way of inducing neuroplasticity in mature neurons is by disinhibiting the principal neurons, which remains to be rigorously tested for a number of clinically important anxiolytics, sedatives and anesthetics in different parts of the circuitry.

  5. Novel bacterial consortia isolated from plastic garbage processing areas demonstrated enhanced degradation for low density polyethylene.

    PubMed

    Skariyachan, Sinosh; Manjunatha, Vishal; Sultana, Subiya; Jois, Chandana; Bai, Vidya; Vasist, Kiran S

    2016-09-01

    This study aimed to formulate novel microbial consortia isolated from plastic garbage processing areas and thereby devise an eco-friendly approach for enhanced degradation of low-density polyethylene (LDPE). The LDPE degrading bacteria were screened and microbiologically characterized. The best isolates were formulated as bacterial consortia, and degradation efficiency was compared with the consortia formulated using known isolates obtained from the Microbial Culture Collection Centre (MTCC). The degradation products were analyzed by FTIR, GC-FID, tensile strength, and SEM. The bacterial consortia were characterized by 16S ribosomal DNA (rDNA) sequencing. The formulated bacterial consortia demonstrated 81 ± 4 and 38 ± 3 % of weight reduction for LDPE strips and LDPE pellets, respectively, over a period of 120 days. However, the consortia formulated by MTCC strains demonstrated 49 ± 4 and 20 ± 2 % of weight reduction for LDPE strips and pellets, respectively, for the same period. Furthermore, the three isolates in its individual application exhibited 70 ± 4, 68 ± 4, and 64 ± 4 % weight reduction for LDPE strips and 21 ± 2, 28 ± 2, 24 ± 2 % weight reduction for LDPE pellets over a period of 120 days (p < 0.05). The end product analysis showed structural changes and formation of bacterial film on degraded LDPE strips. The 16S rDNA characterization of bacterial consortia revealed that these organisms were novel strains and designated as Enterobacter sp. bengaluru-btdsce01, Enterobacter sp. bengaluru-btdsce02, and Pantoea sp. bengaluru-btdsce03. The current study thus suggests that industrial scale-up of these microbial consortia probably provides better insights for waste management of LDPE and similar types of plastic garbage.

  6. GABAA receptor drugs and neuronal plasticity in reward and aversion: focus on the ventral tegmental area

    PubMed Central

    Vashchinkina, Elena; Panhelainen, Anne; Aitta-aho, Teemu; Korpi, Esa R.

    2014-01-01

    GABAA receptors are the main fast inhibitory neurotransmitter receptors in the mammalian brain, and targets for many clinically important drugs widely used in the treatment of anxiety disorders, insomnia and in anesthesia. Nonetheless, there are significant risks associated with the long-term use of these drugs particularly related to development of tolerance and addiction. Addictive mechanisms of GABAA receptor drugs are poorly known, but recent findings suggest that those drugs may induce aberrant neuroadaptations in the brain reward circuitry. Recently, benzodiazepines, acting on synaptic GABAA receptors, and modulators of extrasynaptic GABAA receptors (THIP and neurosteroids) have been found to induce plasticity in the ventral tegmental area (VTA) dopamine neurons and their main target projections. Furthermore, depending whether synaptic or extrasynaptic GABAA receptor populations are activated, the behavioral outcome of repeated administration seems to correlate with rewarding or aversive behavioral responses, respectively. The VTA dopamine neurons project to forebrain centers such as the nucleus accumbens and medial prefrontal cortex, and receive afferent projections from these brain regions and especially from the extended amygdala and lateral habenula, forming the major part of the reward and aversion circuitry. Both synaptic and extrasynaptic GABAA drugs inhibit the VTA GABAergic interneurons, thus activating the VTA DA neurons by disinhibition and this way inducing glutamatergic synaptic plasticity. However, the GABAA drugs failed to alter synaptic spine numbers as studied from Golgi-Cox-stained VTA dendrites. Since the GABAergic drugs are known to depress the brain metabolism and gene expression, their likely way of inducing neuroplasticity in mature neurons is by disinhibiting the principal neurons, which remains to be rigorously tested for a number of clinically important anxiolytics, sedatives and anesthetics in different parts of the circuitry. PMID

  7. Novel bacterial consortia isolated from plastic garbage processing areas demonstrated enhanced degradation for low density polyethylene.

    PubMed

    Skariyachan, Sinosh; Manjunatha, Vishal; Sultana, Subiya; Jois, Chandana; Bai, Vidya; Vasist, Kiran S

    2016-09-01

    This study aimed to formulate novel microbial consortia isolated from plastic garbage processing areas and thereby devise an eco-friendly approach for enhanced degradation of low-density polyethylene (LDPE). The LDPE degrading bacteria were screened and microbiologically characterized. The best isolates were formulated as bacterial consortia, and degradation efficiency was compared with the consortia formulated using known isolates obtained from the Microbial Culture Collection Centre (MTCC). The degradation products were analyzed by FTIR, GC-FID, tensile strength, and SEM. The bacterial consortia were characterized by 16S ribosomal DNA (rDNA) sequencing. The formulated bacterial consortia demonstrated 81 ± 4 and 38 ± 3 % of weight reduction for LDPE strips and LDPE pellets, respectively, over a period of 120 days. However, the consortia formulated by MTCC strains demonstrated 49 ± 4 and 20 ± 2 % of weight reduction for LDPE strips and pellets, respectively, for the same period. Furthermore, the three isolates in its individual application exhibited 70 ± 4, 68 ± 4, and 64 ± 4 % weight reduction for LDPE strips and 21 ± 2, 28 ± 2, 24 ± 2 % weight reduction for LDPE pellets over a period of 120 days (p < 0.05). The end product analysis showed structural changes and formation of bacterial film on degraded LDPE strips. The 16S rDNA characterization of bacterial consortia revealed that these organisms were novel strains and designated as Enterobacter sp. bengaluru-btdsce01, Enterobacter sp. bengaluru-btdsce02, and Pantoea sp. bengaluru-btdsce03. The current study thus suggests that industrial scale-up of these microbial consortia probably provides better insights for waste management of LDPE and similar types of plastic garbage. PMID:27278068

  8. Lead carbonate scintillator materials

    DOEpatents

    Derenzo, Stephen E.; Moses, William W.

    1991-01-01

    Improved radiation detectors containing lead carbonate or basic lead carbonate as the scintillator element are disclosed. Both of these scintillators have been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to other known scintillator materials. The radiation detectors disclosed are favorably suited for use in general purpose detection and in medical uses.

  9. Scintillator reflective layer coextrusion

    DOEpatents

    Yun, Jae-Chul; Para, Adam

    2001-01-01

    A polymeric scintillator has a reflective layer adhered to the exterior surface thereof. The reflective layer comprises a reflective pigment and an adhesive binder. The adhesive binder includes polymeric material from which the scintillator is formed. A method of forming the polymeric scintillator having a reflective layer adhered to the exterior surface thereof is also provided. The method includes the steps of (a) extruding an inner core member from a first amount of polymeric scintillator material, and (b) coextruding an outer reflective layer on the exterior surface of the inner core member. The outer reflective layer comprises a reflective pigment and a second amount of the polymeric scintillator material.

  10. Protected areas in the Atlantic facing the hazards of micro-plastic pollution: first diagnosis of three islands in the Canary Current.

    PubMed

    Baztan, Juan; Carrasco, Ana; Chouinard, Omer; Cleaud, Muriel; Gabaldon, Jesús E; Huck, Thierry; Jaffrès, Lionel; Jorgensen, Bethany; Miguelez, Aquilino; Paillard, Christine; Vanderlinden, Jean-Paul

    2014-03-15

    Coastal zones and the biosphere as a whole show signs of cumulative degradation due to the use and disposal of plastics. To better understand the manifestation of plastic pollution in the Atlantic Ocean, we partnered with local communities to determine the concentrations of micro-plastics in 125 beaches on three islands in the Canary Current: Lanzarote, La Graciosa, and Fuerteventura. We found that, in spite of being located in highly-protected natural areas, all beaches in our study area are exceedingly vulnerable to micro-plastic pollution, with pollution levels reaching concentrations greater than 100 g of plastic in 1l of sediment. This paper contributes to ongoing efforts to develop solutions to plastic pollution by addressing the questions: (i) Where does this pollution come from?; (ii) How much plastic pollution is in the world's oceans and coastal zones?; (iii) What are the consequences for the biosphere?; and (iv) What are possible solutions? PMID:24433999

  11. Protected areas in the Atlantic facing the hazards of micro-plastic pollution: first diagnosis of three islands in the Canary Current.

    PubMed

    Baztan, Juan; Carrasco, Ana; Chouinard, Omer; Cleaud, Muriel; Gabaldon, Jesús E; Huck, Thierry; Jaffrès, Lionel; Jorgensen, Bethany; Miguelez, Aquilino; Paillard, Christine; Vanderlinden, Jean-Paul

    2014-03-15

    Coastal zones and the biosphere as a whole show signs of cumulative degradation due to the use and disposal of plastics. To better understand the manifestation of plastic pollution in the Atlantic Ocean, we partnered with local communities to determine the concentrations of micro-plastics in 125 beaches on three islands in the Canary Current: Lanzarote, La Graciosa, and Fuerteventura. We found that, in spite of being located in highly-protected natural areas, all beaches in our study area are exceedingly vulnerable to micro-plastic pollution, with pollution levels reaching concentrations greater than 100 g of plastic in 1l of sediment. This paper contributes to ongoing efforts to develop solutions to plastic pollution by addressing the questions: (i) Where does this pollution come from?; (ii) How much plastic pollution is in the world's oceans and coastal zones?; (iii) What are the consequences for the biosphere?; and (iv) What are possible solutions?

  12. Energy Transfer Based Nanocomposite Scintillator for Radiation Detection

    NASA Astrophysics Data System (ADS)

    Aslam, Soha; Sahi, Sunil; Chen, Wei; Ma, Lun; Kenarangui, Rasool

    2014-09-01

    Scintillators are the materials that emit light upon irradiation with high energy radiation like X-ray or gamma-ray. Inorganic single crystal and organic (plastic and liquid) are the two most used scintillator types. Both of these scintillator kinds have advantages and disadvantages. Inorganic single crystals are expensive and difficult to grow in desire shape and size. Also, single crystal scintillator such as NaI and CsI are very hygroscopic. On the other hand, organic scintillators have low density which limits their applications in gamma spectroscopy. Due to high quantum yield and size dependent emission, nanoparticles have attracted interested in various field of research. Here, we have studies the nanoparticles for radiation detection. We have synthesized nanoparticles of Cerium fluoride (CeF3), Zinc Oxide (ZnO), Cadmium Telluride (CdTe), Copper complex and Zinc sulfide (ZnS). We have used Fluorescence Resonance Energy Transfer (FRET) principle to enhance the luminescence properties of nanocomposite scintillator. Nanocomposites scintillators are structurally characterized with X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Optical properties are studied using Photoluminescence, UV-Visible and X-ray. Enhancements in the luminescence are observed under UV and X-ray excitation. Preliminary studies shows nanocomposite scintillators are promising for radiation detection. Scintillators are the materials that emit light upon irradiation with high energy radiation like X-ray or gamma-ray. Inorganic single crystal and organic (plastic and liquid) are the two most used scintillator types. Both of these scintillator kinds have advantages and disadvantages. Inorganic single crystals are expensive and difficult to grow in desire shape and size. Also, single crystal scintillator such as NaI and CsI are very hygroscopic. On the other hand, organic scintillators have low density which limits their applications in gamma spectroscopy. Due to high quantum

  13. New Efficient Organic Scintillators Derived from Pyrazoline.

    PubMed

    Bliznyuk, Valery N; Seliman, Ayman F; Ishchenko, Alexander A; Derevyanko, Nadezhda A; DeVol, Timothy A

    2016-05-25

    We report on the synthesis, spectroscopic and scintillation properties of three new pyrazoline core based fluorophores. Fluorescence properties of the fluorophores have been studied both in a solution state and in a solid polyvinyltoluene (PVT) resin matrix of different porosity. The synthesized fluorophores were found to be promising candidates for application in plastic scintillators for detection of ionizing radiation (alpha, beta particles, γ rays and neutrons) and demonstrated superior efficiency in comparison to the existing commercially used fluorophores (2-(1-naphthyl)-5-phenyloxazole (αNPO), 9,10-diphenylanthracene, etc.). Moreover, the suggested synthetic route allows functionalization of the fluorophores with a vinyl group for further covalent bound to the PVT or other vinyl polymer matrices, which dramatically improves chemical stability of the system simultaneously improving the photoluminescence quantum yield. Possible mechanisms of the enhanced scintillation properties are discussed based on preliminary quantum mechanical calculations and spectroscopic characteristics of the fluorophores under study. PMID:27163887

  14. Glutamatergic plasticity in medial prefrontal cortex and ventral tegmental area following extended-access cocaine self-administration

    PubMed Central

    Ghasemzadeh, M. Behnam; Vasudevan, Preethi; Giles, Chad; Purgianto, Anthony; Seubert, Chad; Mantsch, John R.

    2013-01-01

    Glutamate signaling in prefrontal cortex and ventral tegmental area plays an important role in the molecular and behavioral plasticity associated with addiction to drugs of abuse. The current study investigated the expression and postsynaptic density redistribution of glutamate receptors and synaptic scaffolding proteins in dorsomedial and ventromedial prefrontal cortex and ventral tegmental area after cocaine self-administration. After 14 days of extended-access (6hr/day) cocaine self-administration, rats were exposed to one of three withdrawal regimen for 10 days. Animals either stayed in home cages (Home), returned to self-administration boxes with the levers withdrawn (Box), or underwent extinction training (Extinction). Extinction training was associated with significant glutamatergic plasticity. In dorsomedial prefrontal cortex of the Extinction group, there was an increase in postsynaptic density GluR1, PSD95, and actin proteins; while postsynaptic content of mGluR5 receptor protein decreased and there was no change in NMDAR1, Homer1b/c, or PICK1 proteins. These changes were not observed in ventromedial prefrontal cortex or ventral tegmental area. In ventral tegmental area, Extinction training reversed the decreased postsynaptic density NMDAR1 protein in the Home and Box withdrawal groups. These data suggest that extinction of drug seeking is associated with selective glutamatergic plasticity in prefrontal cortex and ventral tegmental area that include modulation of receptor trafficking to postsynaptic density. PMID:21855055

  15. Contamination and risk of heavy metals in soils and sediments from a typical plastic waste recycling area in North China.

    PubMed

    Tang, Zhenwu; Zhang, Lianzhen; Huang, Qifei; Yang, Yufei; Nie, Zhiqiang; Cheng, Jiali; Yang, Jun; Wang, Yuwen; Chai, Miao

    2015-12-01

    Plastic wastes are increasingly being recycled in many countries. However, available information on the metals released into the environment during recycling processes is rare. In this study, the contamination features and risks of eight heavy metals in soils and sediments were investigated in Wen'an, a typical plastic recycling area in North China. The surface soils and sediments have suffered from moderate to high metal pollution and in particular, high Cd and Hg pollution. The mean concentrations of Cd and Hg were 0.355 and 0.408 mg kg(-1), respectively, in the soils and 1.53 and 2.10 mg kg(-1), respectively, in the sediments. The findings suggested that there is considerable to high potential ecological risks in more than half of the soils and high potential ecological risk in almost all sediments. Although the health risk levels from exposure to soil metals were acceptable for adults, the non-carcinogenic risks to local children exceeded the acceptable level. Source assessment indicated that heavy metals in soils and sediments were mainly derived from inputs from poorly controlled plastic waste recycling operations in this area. The results suggested that the risks associated with heavy metal pollution from plastic waste recycling should be of great concern.

  16. Contamination and risk of heavy metals in soils and sediments from a typical plastic waste recycling area in North China.

    PubMed

    Tang, Zhenwu; Zhang, Lianzhen; Huang, Qifei; Yang, Yufei; Nie, Zhiqiang; Cheng, Jiali; Yang, Jun; Wang, Yuwen; Chai, Miao

    2015-12-01

    Plastic wastes are increasingly being recycled in many countries. However, available information on the metals released into the environment during recycling processes is rare. In this study, the contamination features and risks of eight heavy metals in soils and sediments were investigated in Wen'an, a typical plastic recycling area in North China. The surface soils and sediments have suffered from moderate to high metal pollution and in particular, high Cd and Hg pollution. The mean concentrations of Cd and Hg were 0.355 and 0.408 mg kg(-1), respectively, in the soils and 1.53 and 2.10 mg kg(-1), respectively, in the sediments. The findings suggested that there is considerable to high potential ecological risks in more than half of the soils and high potential ecological risk in almost all sediments. Although the health risk levels from exposure to soil metals were acceptable for adults, the non-carcinogenic risks to local children exceeded the acceptable level. Source assessment indicated that heavy metals in soils and sediments were mainly derived from inputs from poorly controlled plastic waste recycling operations in this area. The results suggested that the risks associated with heavy metal pollution from plastic waste recycling should be of great concern. PMID:26318969

  17. Shifting scintillator neutron detector

    SciTech Connect

    Clonts, Lloyd G; Cooper, Ronald G; Crow, Jr., Morris Lowell; Hannah, Bruce W; Hodges, Jason P; Richards, John D; Riedel, Richard A

    2014-03-04

    Provided are sensors and methods for detecting thermal neutrons. Provided is an apparatus having a scintillator for absorbing a neutron, the scintillator having a back side for discharging a scintillation light of a first wavelength in response to the absorbed neutron, an array of wavelength-shifting fibers proximate to the back side of the scintillator for shifting the scintillation light of the first wavelength to light of a second wavelength, the wavelength-shifting fibers being disposed in a two-dimensional pattern and defining a plurality of scattering plane pixels where the wavelength-shifting fibers overlap, a plurality of photomultiplier tubes, in coded optical communication with the wavelength-shifting fibers, for converting the light of the second wavelength to an electronic signal, and a processor for processing the electronic signal to identify one of the plurality of scattering plane pixels as indicative of a position within the scintillator where the neutron was absorbed.

  18. Lead carbonate scintillator materials

    DOEpatents

    Derenzo, S.E.; Moses, W.W.

    1991-05-14

    Improved radiation detectors containing lead carbonate or basic lead carbonate as the scintillator element are disclosed. Both of these scintillators have been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to other known scintillator materials. The radiation detectors disclosed are favorably suited for use in general purpose detection and in medical uses. 3 figures.

  19. HEAVY METAL LOADED PLASTIC SCINTILLATING COMPOSITIONS

    DOEpatents

    Hyman, M. Jr.

    1962-06-26

    Thls lnventlon relates to a plastlc sclntlllatlon composltlon havlng lncorporated ln the base plastlc a lead compound. Thls compound forms a haze- free sclntillator. The lead compound has the general formula (R/sub 4/) x from the group consisting of hydrogen, alky, and phenyl, R4 ls selected from the group conslstlng of acrylyl and methacryiyl radlcals, and x ls a number from 0,5 to 1; however, when R/sub 1/, R/sub 2/, and R/sub 3/ are all hydrogen the x ls equal to 1. The phosphor ln the sclntlllatlng compositlon and the lead compound can be dlssolved ln a polymerlc resln selected from the group conslsting of polyvinyl toluene and copolymers of vlnyl toluene and cyclohexyl methacrylate. (AEC)

  20. Scintillation Breakdowns in Chip Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2008-01-01

    Scintillations in solid tantalum capacitors are momentarily local breakdowns terminated by a self-healing or conversion to a high-resistive state of the manganese oxide cathode. This conversion effectively caps the defective area of the tantalum pentoxide dielectric and prevents short-circuit failures. Typically, this type of breakdown has no immediate catastrophic consequences and is often considered as nuisance rather than a failure. Scintillation breakdowns likely do not affect failures of parts under surge current conditions, and so-called "proofing" of tantalum chip capacitors, which is a controllable exposure of the part after soldering to voltages slightly higher than the operating voltage to verify that possible scintillations are self-healed, has been shown to improve the quality of the parts. However, no in-depth studies of the effect of scintillations on reliability of tantalum capacitors have been performed so far. KEMET is using scintillation breakdown testing as a tool for assessing process improvements and to compare quality of different manufacturing lots. Nevertheless, the relationship between failures and scintillation breakdowns is not clear, and this test is not considered as suitable for lot acceptance testing. In this work, scintillation breakdowns in different military-graded and commercial tantalum capacitors were characterized and related to the rated voltages and to life test failures. A model for assessment of times to failure, based on distributions of breakdown voltages, and accelerating factors of life testing are discussed.

  1. Highly sensitive large-area bolometers for scintillation studies below 100 mK (from near IR to soft x rays)

    NASA Astrophysics Data System (ADS)

    Coron, Noel J.; de Marcillac, Pierre; Leblanc, Jacques; Dambier, Gérard; Moalic, Jean-Pierre

    2004-02-01

    At very low temperature large area bolometers may show a better sensitivity than photomultipliers or semiconductor diodes, while allowing fluorescence measurements of cool targets with no window, no infrared background, good optical couplings and a flat response on a large absorption bandpass. The optical absorber of these composite bolometers can be matched to the desired bandpass. Here we present the design, the performances and calibration tests of a new generation of large area (5 cm2) optical bolometers with a pure germanium disk absorbing on a wide spectral band from near-IR to X-rays. Performances obtained at 25 mK are very promising : Noise Equivalent Power as low as 4x10-17 W/√Hz in the photometry mode, energy threshold about 50 eV in the single photon detection mode, and time constant τ~3 ms. These detectors of low mass (0.25 g) have been recently successfully used for detecting the fluorescence emitted by much more massive bolometers, having for example a BGO (92 g), or a CaWO4 (54 g) target. The simultaneous detection of heat and light in these <> permits the identification of each event in the massive target (α decay, or γ cosmic ray interaction, neutron recoil…). Thanks to the consecutive excellent subtraction of the radioactive and cosmic rays background, it is a powerful tool developed by several groups for fundamental research : study of very rare decays of atoms, measurement of internal very low radioactivity content in single crystals, direct detection of dark matter recoils in massive fluorescence targets, detection of solar neutrino fluorescence events in liquid 4He…Recently obtained results which support this new promising field are reminded: the first detection of the rare alpha decay of 209Bi, and new scintillation data on Al2O3 (sapphire), LiF or TeO2 at 20mK. We discuss the ultimate performances at 12 mK of the optical bolometers as a function of their area, as well as the optimisation of their absorbing part to

  2. Performance comparison of scintillators for alpha particle detectors

    NASA Astrophysics Data System (ADS)

    Morishita, Yuki; Yamamoto, Seiichi; Izaki, Kenji; Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio

    2014-11-01

    Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd2Si2O7 (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM

  3. A plastic relationship between vinculin-mediated tension and adhesion complex area defines adhesion size and lifetime

    NASA Astrophysics Data System (ADS)

    Hernández-Varas, Pablo; Berge, Ulrich; Lock, John G.; Strömblad, Staffan

    2015-06-01

    Cell-matrix adhesions are central mediators of mechanotransduction, yet the interplay between force and adhesion regulation remains unclear. Here we use live cell imaging to map time-dependent cross-correlations between vinculin-mediated tension and adhesion complex area, revealing a plastic, context-dependent relationship. Interestingly, while an expected positive cross-correlation dominated in mid-sized adhesions, small and large adhesions display negative cross-correlation. Furthermore, although large changes in adhesion complex area follow vinculin-mediated tension alterations, small increases in area precede vinculin-mediated tension dynamics. Modelling based on this mapping of the vinculin-mediated tension-adhesion complex area relationship confirms its biological validity, and indicates that this relationship explains adhesion size and lifetime limits, keeping adhesions focal and transient. We also identify a subpopulation of steady-state adhesions whose size and vinculin-mediated tension become stabilized, and whose disassembly may be selectively microtubule-mediated. In conclusion, we define a plastic relationship between vinculin-mediated tension and adhesion complex area that controls fundamental cell-matrix adhesion properties.

  4. Multi-PSPMT scintillation camera

    SciTech Connect

    Pani, R.; Pellegrini, R.; Trotta, G.; Scopinaro, F.; Soluri, A.; Vincentis, G. de; Scafe, R.; Pergola, A.

    1999-06-01

    Gamma ray imaging is usually accomplished by the use of a relatively large scintillating crystal coupled to either a number of photomultipliers (PMTs) (Anger Camera) or to a single large Position Sensitive PMT (PSPMT). Recently the development of new diagnostic techniques, such as scintimammography and radio-guided surgery, have highlighted a number of significant limitations of the Anger camera in such imaging procedures. In this paper a dedicated gamma camera is proposed for clinical applications with the aim of improving image quality by utilizing detectors with an appropriate size and shape for the part of the body under examination. This novel scintillation camera is based upon an array of PSPMTs (Hamamatsu R5900-C8). The basic concept of this camera is identical to the Anger Camera with the exception of the substitution of PSPMTs for the PMTs. In this configuration it is possible to use the high resolution of the PSPMTs and still correctly position events lying between PSPMTs. In this work the test configuration is a 2 by 2 array of PSPMTs. Some advantages of this camera are: spatial resolution less than 2 mm FWHM, good linearity, thickness less than 3 cm, light weight, lower cost than equivalent area PSPMT, large detection area when coupled to scintillating arrays, small dead boundary zone (< 3 mm) and flexibility in the shape of the camera.

  5. The homestake surface-underground scintillations: Description

    NASA Technical Reports Server (NTRS)

    Cherry, M. L.; Corbato, S.; Daily, T.; Fenyves, E. J.; Kieda, D.; Lande, K.; Lee, C. K.

    1985-01-01

    Two new detectors are currently under construction at the Homestake Gold Mine a 140-ton Large Area Scintillation Detector (LASD) with an upper surface area of 130 square meters, a geometry factor (for an isotropic flux) of 1200 square meters, sr, and a depth of 4200 m.w.e.; and a surface air shower array consisting of 100 scintillator elements, each 3 square meters, spanning an area of approximately square kilometers. Underground, half of the LASD is currently running and collecting muon data; on the surface, the first section of the air shower array will begin operation in the spring of 1985. The detectors and their capabilities are described.

  6. Training of binocular rivalry suppression suggests stimulus-specific plasticity in monocular and binocular visual areas.

    PubMed

    Vergeer, Mark; Wagemans, Johan; van Ee, Raymond

    2016-05-10

    The plasticity of the human brain, as shown in perceptual learning, is generally reflected by improved task performance after training. Here, we show that perceptual suppression can be increased through training. In the first experiment, binocular rivalry suppression of a specific orientation was trained, leading to a relative reduction in sensitivity to the trained orientation. In a second experiment, two orthogonal orientations were suppressed in alternating training blocks, in the left and right eye, respectively. This double-training procedure lead to reduced sensitivity for the orientation that was suppression-trained in each specific eye, implying that training of feature suppression is specific for the eye in which the oriented grating was presented during training. Results of a control experiment indicate that the obtained effects are indeed due to suppression during training, instead of being merely due to the repetitive presentation of the oriented gratings. Visual plasticity is essential for a person's visual development. The finding that plasticity can result in increased perceptual suppression reported here may prove to be significant in understanding human visual development. It emphasizes that for stable vision, not only the enhancement of relevant signals is crucial, but also the reliable and stable suppression of (task) irrelevant signals.

  7. The effect of axial force and contact angle on the welded area of plastic tube welded by ultrasonic welding

    NASA Astrophysics Data System (ADS)

    Thinvongpituk, C.; Bootwong, A.; Watanabe, Y.

    2010-03-01

    This study was aimed to apply the use of ultrasonic welding to weld round plastic tubes. The ultrasonic welding machine was designed to be able to work with a normal ultrasonic welding transducer by rotating the tube while it is being welded. The specimens used in this study were round plastic tubes (PMMA) with diameter of 35 mm and 2 mm thickness. End of each tube was machined to have angle of 2.8, 3.8 and 5.7 degree in order to create contact angle at the interface. The specimens were welded with frequency of 28 kHz and tube rotational speeds of 25 rpm, 45 rpm and 100 rpm. The axial force was applied to the tube in order to enhance the quality of joint. The experimental result revealed that the modified ultrasonic welding machine can generate the welded area around the circumference of tube. It was found that the axial force and contact angle have some effect to the quality of joint. The contact angle of 2.8/2.8 provided highest welded area compared to 3.8/3.8 and 5.7/5.7 degree of contact angle. In addition, the axial force between 80 N - 120 N provided high value of welded area. The pattern of welded area is also presented and discussed in the paper.

  8. The effect of axial force and contact angle on the welded area of plastic tube welded by ultrasonic welding

    NASA Astrophysics Data System (ADS)

    Thinvongpituk, C.; Bootwong, A.; Watanabe, Y.

    2009-12-01

    This study was aimed to apply the use of ultrasonic welding to weld round plastic tubes. The ultrasonic welding machine was designed to be able to work with a normal ultrasonic welding transducer by rotating the tube while it is being welded. The specimens used in this study were round plastic tubes (PMMA) with diameter of 35 mm and 2 mm thickness. End of each tube was machined to have angle of 2.8, 3.8 and 5.7 degree in order to create contact angle at the interface. The specimens were welded with frequency of 28 kHz and tube rotational speeds of 25 rpm, 45 rpm and 100 rpm. The axial force was applied to the tube in order to enhance the quality of joint. The experimental result revealed that the modified ultrasonic welding machine can generate the welded area around the circumference of tube. It was found that the axial force and contact angle have some effect to the quality of joint. The contact angle of 2.8/2.8 provided highest welded area compared to 3.8/3.8 and 5.7/5.7 degree of contact angle. In addition, the axial force between 80 N - 120 N provided high value of welded area. The pattern of welded area is also presented and discussed in the paper.

  9. Neutron spectroscopy with scintillation detectors using wavelets

    NASA Astrophysics Data System (ADS)

    Hartman, Jessica

    The purpose of this research was to study neutron spectroscopy using the EJ-299-33A plastic scintillator. This scintillator material provided a novel means of detection for fast neutrons, without the disadvantages of traditional liquid scintillation materials. EJ-299-33A provided a more durable option to these materials, making it less likely to be damaged during handling. Unlike liquid scintillators, this plastic scintillator was manufactured from a non-toxic material, making it safer to use, as well as easier to design detectors. The material was also manufactured with inherent pulse shape discrimination abilities, making it suitable for use in neutron detection. The neutron spectral unfolding technique was developed in two stages. Initial detector response function modeling was carried out through the use of the MCNPX Monte Carlo code. The response functions were developed for a monoenergetic neutron flux. Wavelets were then applied to smooth the response function. The spectral unfolding technique was applied through polynomial fitting and optimization techniques in MATLAB. Verification of the unfolding technique was carried out through the use of experimentally determined response functions. These were measured on the neutron source based on the Van de Graff accelerator at the University of Kentucky. This machine provided a range of monoenergetic neutron beams between 0.1 MeV and 24 MeV, making it possible to measure the set of response functions of the EJ-299-33A plastic scintillator detector to neutrons of specific energies. The response of a plutonium-beryllium (PuBe) source was measured using the source available at the University of Nevada, Las Vegas. The neutron spectrum reconstruction was carried out using the experimentally measured response functions. Experimental data was collected in the list mode of the waveform digitizer. Post processing of this data focused on the pulse shape discrimination analysis of the recorded response functions to remove the

  10. Encapsulated scintillators monitor /sup 3/H-solute concentrations

    SciTech Connect

    Kirk, G.; Gruner, S.

    1982-02-01

    The short range of the /sup 3/H beta allows shielding of microbeds of scintillator by a several um thick coating of a water based gel. Gels may be used which are permeable to a wide variety of tritiated molecules. Thus, the light output of a mixture of the coated beads and a solution of the tritiated compound is proportional to the solution concentration of the tritiated substance. The mixture may also contain particles to which the gel is impermeable, such as cells, vesicles, large proteins, etc., but which can alter the concentration of the tritiated compound by uptake or release. In this case, the light output monitors the fractional uptake of the tritiated material. The design criteria for encapsulating the scintillators and dynamically monitoring the scintillation output are discussed. A simple method for encapsulating plastic scintillator microbeads, suitable for monitoring slow concentration changes, is described and tested.

  11. Fiber scintillator/streak camera detector for burn history measurement in inertial confinement fusion experiment

    SciTech Connect

    Miyanaga, N.; Ohba, N.; Fujimoto, K.

    1997-01-01

    To measure the burn history in an inertial confinement fusion experiment, we have developed a new neutron detector based on plastic scintillation fibers. Twenty-five fiber scintillators were arranged in a geometry compensation configuration by which the time-of-flight difference of the neutrons is compensated by the transit time difference of light passing through the fibers. Each fiber scintillator is spliced individually to an ultraviolet optical fiber that is coupled to a streak camera. We have demonstrated a significant improvement of sensitivity compared with the usual bulk scintillator coupled to a bundle of the same ultraviolet fibers. {copyright} {ital 1997 American Institute of Physics.}

  12. Ionospheric Scintillation Explorer (ISX)

    NASA Astrophysics Data System (ADS)

    Iuliano, J.; Bahcivan, H.

    2015-12-01

    NSF has recently selected Ionospheric Scintillation Explorer (ISX), a 3U Cubesat mission to explore the three-dimensional structure of scintillation-scale ionospheric irregularities associated with Equatorial Spread F (ESF). ISX is a collaborative effort between SRI International and Cal Poly. This project addresses the science question: To what distance along a flux tube does an irregularity of certain transverse-scale extend? It has been difficult to measure the magnetic field-alignment of scintillation-scale turbulent structures because of the difficulty of sampling a flux tube at multiple locations within a short time. This measurement is now possible due to the worldwide transition to DTV, which presents unique signals of opportunity for remote sensing of ionospheric irregularities from numerous vantage points. DTV spectra, in various formats, contain phase-stable, narrowband pilot carrier components that are transmitted simultaneously. A 4-channel radar receiver will simultaneously record up to 4 spatially separated transmissions from the ground. Correlations of amplitude and phase scintillation patterns corresponding to multiple points on the same flux tube will be a measure of the spatial extent of the structures along the magnetic field. A subset of geometries where two or more transmitters are aligned with the orbital path will be used to infer the temporal development of the structures. ISX has the following broad impact. Scintillation of space-based radio signals is a space weather problem that is intensively studied. ISX is a step toward a CubeSat constellation to monitor worldwide TEC variations and radio wave distortions on thousands of ionospheric paths. Furthermore, the rapid sampling along spacecraft orbits provides a unique dataset to deterministically reconstruct ionospheric irregularities at scintillation-scale resolution using diffraction radio tomography, a technique that enables prediction of scintillations at other radio frequencies, and

  13. Photodetectors for Scintillator Proportionality Measurement

    SciTech Connect

    Moses, William W.; Choong, Woon-Seng; Hull, Giulia; Payne, Steve; Cherepy, Nerine; Valentine, J.D.

    2010-10-18

    We evaluate photodetectors for use in a Compton Coincidence apparatus designed for measuring scintillator proportionality. There are many requirements placed on the photodetector in these systems, including active area, linearity, and the ability to accurately measure low light levels (which implies high quantum efficiency and high signal-to-noise ratio). Through a combination of measurement and Monte Carlo simulation, we evaluate a number of potential photodetectors, especially photomultiplier tubes and hybrid photodetectors. Of these, we find that the most promising devices available are photomultiplier tubes with high ({approx}50%) quantum efficiency, although hybrid photodetectors with high quantum efficiency would be preferable.

  14. Scintillator Measurements for SNO+

    NASA Astrophysics Data System (ADS)

    Kaptanoglu, Tanner; SNO+ Collaboration

    2016-03-01

    SNO+ is a neutrino detector located 2km underground in the SNOLAB facility with the primary goal of searching for neutrinoless double beta decay. The detector will be filled with a liquid scintillator target primarily composed of linear alkyl benzene (LAB). As charged particles travel through the detector the LAB produces scintillation light which is detected by almost ten thousand PMTs. The LAB is loaded with Te130, an isotope known to undergo double beta decay. Additionally, the LAB is mixed with an additional fluor and wavelength shifter to improve the light output and shift the light to a wavelength regime in which the PMTs are maximally efficient. The precise scintillator optics drastically affect the ultimate sensitivity of SNO+. I will present work being done to measure the optical properties of the SNO+ scintillator cocktail. The measured properties are used as input to a scintillation model that allows us to extrapolate to the SNO+ scale and ultimately predict the sensitivity of the experiment. Additionally, I will present measurements done to characterize the R5912 PMT, a candidate PMT for the second phase of SNO+ that provides better light collection, improved charge resolution, and a narrower spread in timing.

  15. Divalent europium doped and un-doped calcium iodide scintillators: Scintillator characterization and single crystal growth

    DOE PAGES

    Boatner, L. A.; Ramey, J. O.; Kolopus, J. A.; Neal, John S.

    2015-02-21

    Initially, the alkaline-earth scintillator, CaI2:Eu2+, was discovered around 1964 by Hofstadter, Odell, and Schmidt. Serious practical problems quickly arose, however, that were associated with the growth of large monolithic single crystals of this material due to its lamellar, mica-like structure. As a result of its theoretically higher light yield, CaI2:Eu2+ has the potential to exceed the excellent scintillation performance of SrI2:Eu2+. In fact, theoretical predictions for the light yield of CaI2:Eu2+ scintillators suggested that an energy resolution approaching 2% at 662 keV could be achievable. Like the early SrI2:Eu2+ scintillator, the performance of CaI2:Eu2+ scintillators has traditionally suffered due, atmore » least in part, to outdated materials synthesis, component stoichiometry/purity, and single-crystal-growth techniques. Based on our recent work on SrI2:Eu2+ scintillators in single-crystal form, we have developed new techniques that are applied here to CaI2:Eu2+ and pure CaI2 with the goal of growing large un-cracked crystals and, potentially, realizing the theoretically predicted performance of the CaI2:Eu2+ form of this material. Calcium iodide does not adhere to modern glassy carbon Bridgman crucibles - so there should be no differential thermal-contraction-induced crystal/crucible stresses on cooling that would result in crystal cracking of the lamellar structure of CaI2. Here we apply glassy carbon crucible Bridgman growth, high-purity growth-charge compounds, our molten salt processing/filtration technique, and extended vacuum-melt-pumping methods to the growth of both CaI2:Eu2+ and un-doped CaI2. Moreover, large scintillating single crystals were obtained, and detailed characterization studies of the scintillation properties of CaI2:Eu2+ and pure CaI2 single crystals are presented that include studies of the effects of plastic deformation of the crystals on the scintillator performance.« less

  16. Divalent europium doped and un-doped calcium iodide scintillators: Scintillator characterization and single crystal growth

    SciTech Connect

    Boatner, L. A.; Ramey, J. O.; Kolopus, J. A.; Neal, John S.

    2015-02-21

    scintillation properties of CaI2:Eu2+ and pure CaI2 single crystals are presented that include studies of the effects of plastic deformation of the crystals on the scintillator performance.

  17. Divalent europium doped and un-doped calcium iodide scintillators: Scintillator characterization and single crystal growth

    NASA Astrophysics Data System (ADS)

    Boatner, L. A.; Ramey, J. O.; Kolopus, J. A.; Neal, John S.

    2015-06-01

    The alkaline-earth scintillator, CaI2:Eu2+, was initially discovered around 1964 by Hofstadter, Odell, and Schmidt. Serious practical problems quickly arose, however, that were associated with the growth of large monolithic single crystals of this material due to its lamellar, mica-like structure. As a result of its theoretically higher light yield, CaI2:Eu2+ has the potential to exceed the excellent scintillation performance of SrI2:Eu2+. In fact, theoretical predictions for the light yield of CaI2:Eu2+ scintillators suggested that an energy resolution approaching 2% at 662 keV could be achievable. As in the case of the early SrI2:Eu2+ scintillator, the performance of CaI2:Eu2+ scintillators has traditionally suffered due, at least in part, to outdated materials synthesis, component stoichiometry/purity, and single-crystal-growth techniques. Based on our recent work on SrI2:Eu2+ scintillators in single-crystal form, we have developed new techniques that are applied here to CaI2:Eu2+ and pure CaI2 with the goal of growing large un-cracked crystals and, potentially, realizing the theoretically predicted performance of the CaI2:Eu2+ form of this material. Calcium iodide does not adhere to modern glassy carbon Bridgman crucibles-so there should be no differential thermal-contraction-induced crystal/crucible stresses on cooling that would result in crystal cracking of the lamellar structure of CaI2. Here we apply glassy carbon crucible Bridgman growth, high-purity growth-charge compounds, our molten salt processing/filtration technique, and extended vacuum-melt-pumping methods to the growth of both CaI2:Eu2+ and un-doped CaI2. Large scintillating single crystals were obtained, and detailed characterization studies of the scintillation properties of CaI2:Eu2+ and pure CaI2 single crystals are presented that include studies of the effects of plastic deformation of the crystals on the scintillator performance.

  18. Performance of Europium-Doped Strontium Iodide, Transparent Ceramics and Bismuth-loaded Polymer Scintillators

    SciTech Connect

    Cherepy, N J; Payne, S A; Sturm, B W; O'Neal, S P; Seeley, Z M; Drury, O B; Haselhorst, L K; Rupert, B L; Sanner, R D; Thelin, P A; Fisher, S E; Hawrami, R; Shah, K S; Burger, A; Ramey, J O; Boatner, L A

    2011-08-30

    Recently discovered scintillators for gamma ray spectroscopy, single crystal SrI{sub 2}(Eu), GYGAG(Ce) transparent ceramic and Bismuth-loaded plastics, offer resolution and fabrication advantages compared to commercial scintillators, such as NaI(Tl) and standard PVT plastic. Energy resolution at 662 keV of 2.7% is obtained with SrI{sub 2}(Eu), while 4.5% is obtained with GYGAG(Ce). A new transparent ceramic scintillator for radiographic imaging systems, GLO(Eu) offers high light yield of 70,000 Photons/MeV, high stopping, and low radiation damage. Implementation of single crystal SrI{sub 2}(Eu), Gd-based transparent ceramics, and Bi-loaded plastic scintillators can advance the state-of-the art in ionizing radiation detection systems.

  19. Liquid Scintillator Purification

    SciTech Connect

    Kishimoto, Y.

    2005-09-08

    The KamLAND collaboration has studied background requirements and purification methods needed to observe the 7Be neutrino from the sun. First we will discuss the present background situation in KamLAND where it is found that the main background components are 210Pb and 85Kr. It is then described how to purify the liquid scintillator. The present status and results on how to remove 210Pb from the liquid scintillator are discussed. Specifically, the detailed analysis of the effects of distillation and adsorption techniques are presented.

  20. The ratio of leaf to total photosynthetic area influences shade survival and plastic response to light of green-stemmed leguminous shrub seedlings.

    PubMed

    Valladares, Fernando; Hernández, Libertad G; Dobarro, Iker; García-Pérez, Cristina; Sanz, Rubén; Pugnaire, Francisco I

    2003-04-01

    Different plant species and organs within a plant differ in their plastic response to light. These responses influence their performance and survival in relation to the light environment, which may range from full sunlight to deep shade. Plasticity, especially with regard to physiological features, is linked to a greater capacity to exploit high light and is usually low in shade-tolerant species. Among photosynthetic organs, green stems, which represent a large fraction of the total photosynthetic area of certain species, are hypothesized to be less capable of adjustment to light than leaves, because of biomechanical and hydraulic constraints. The response to light by leaves and stems of six species of leguminous, green-stemmed shrubs from dry and high-light environments was studied by growing seedlings in three light environments: deep shade, moderate shade and sun (3, 30 and 100 % of full sunlight, respectively). Survival in deep shade ranged from 2 % in Retama sphaerocarpa to 74 % in Ulex europaeus. Survival was maximal at moderate shade in all species, ranging from 80 to 98 %. The six species differed significantly in their ratio of leaf to total photosynthetic area, which influenced their light response. Survival in deep shade increased significantly with increasing ratio of leaf to total photosynthetic area, and decreased with increasing plasticity in net photosynthesis and dark respiration. Responses to light differed between stems and leaves within each species. Mean phenotypic plasticity for the variables leaf or stem specific mass, chlorophyll content, chlorophyll a/b ratio, and carotenoid to chlorophyll ratio of leaves, was inversely related to that of stems. Although mean plasticity of stems increased with the ratio of leaf to total photosynthetic area, the mean plasticity of leaves decreased. Shrubs with green stems and a low ratio of leaf to total photosynthetic area are expected to be restricted to well-lit habitats, at least during the seedling

  1. The Ratio of Leaf to Total Photosynthetic Area Influences Shade Survival and Plastic Response to Light of Green‐stemmed Leguminous Shrub Seedlings

    PubMed Central

    VALLADARES, FERNANDO; HERNÁNDEZ, LIBERTAD G.; DOBARRO, IKER; GARCÍA‐PÉREZ, CRISTINA; SANZ, RUBÉN; PUGNAIRE, FRANCISCO I.

    2003-01-01

    Different plant species and organs within a plant differ in their plastic response to light. These responses influence their performance and survival in relation to the light environment, which may range from full sunlight to deep shade. Plasticity, especially with regard to physiological features, is linked to a greater capacity to exploit high light and is usually low in shade‐tolerant species. Among photosynthetic organs, green stems, which represent a large fraction of the total photosynthetic area of certain species, are hypothesized to be less capable of adjustment to light than leaves, because of biomechanical and hydraulic constraints. The response to light by leaves and stems of six species of leguminous, green‐stemmed shrubs from dry and high‐light environments was studied by growing seedlings in three light environments: deep shade, moderate shade and sun (3, 30 and 100 % of full sunlight, respectively). Survival in deep shade ranged from 2 % in Retama sphaerocarpa to 74 % in Ulex europaeus. Survival was maximal at moderate shade in all species, ranging from 80 to 98 %. The six species differed significantly in their ratio of leaf to total photosynthetic area, which influenced their light response. Survival in deep shade increased significantly with increasing ratio of leaf to total photosynthetic area, and decreased with increasing plasticity in net photosynthesis and dark respiration. Responses to light differed between stems and leaves within each species. Mean phenotypic plasticity for the variables leaf or stem specific mass, chlorophyll content, chlorophyll a/b ratio, and carotenoid to chlorophyll ratio of leaves, was inversely related to that of stems. Although mean plasticity of stems increased with the ratio of leaf to total photosynthetic area, the mean plasticity of leaves decreased. Shrubs with green stems and a low ratio of leaf to total photosynthetic area are expected to be restricted to well‐lit habitats, at least during the

  2. SCINTILLATION EXPOSURE RATE DETECTOR

    DOEpatents

    Spears, W.G.

    1960-11-01

    A radiation detector for gamma and x rays is described. The detector comprises a scintillation crystal disposed between a tantalum shield and the input of a photomultiplier tube, the crystal and the shield cooperating so that their combined response to a given quantity of radiation at various energy levels is substantially constant.

  3. Boron loaded scintillator

    DOEpatents

    Bell, Zane William [Oak Ridge, TN; Brown, Gilbert Morris [Knoxville, TN; Maya, Leon [Knoxville, TN; Sloop, Jr., Frederick Victor; Sloop, Jr., Frederick Victor [Oak Ridge, TN

    2009-10-20

    A scintillating composition for detecting neutrons and other radiation comprises a phenyl containing silicone rubber with carborane units and at least one phosphor molecule. The carbonate units can either be a carborane molecule dispersed in the rubber with the aid of a compatibilization agent or can be covalently bound to the silicone.

  4. Scintillator requirements for medical imaging

    SciTech Connect

    Moses, William W.

    1999-09-01

    Scintillating materials are used in a variety of medical imaging devices. This paper presents a description of four medical imaging modalities that make extensive use of scintillators: planar x-ray imaging, x-ray computed tomography (x-ray CT), SPECT (single photon emission computed tomography) and PET (positron emission tomography). The discussion concentrates on a description of the underlying physical principles by which the four modalities operate. The scintillator requirements for these systems are enumerated and the compromises that are made in order to maximize imaging performance utilizing existing scintillating materials are discussed, as is the potential for improving imaging performance by improving scintillator properties.

  5. Scintillator Waveguide For Sensing Radiation

    DOEpatents

    Bliss, Mary; Craig, Richard A.; Reeder; Paul L.

    2003-04-22

    The present invention is an apparatus for detecting ionizing radiation, having: a waveguide having a first end and a second end, the waveguide formed of a scintillator material wherein the therapeutic ionizing radiation isotropically generates scintillation light signals within the waveguide. This apparatus provides a measure of radiation dose. The apparatus may be modified to permit making a measure of location of radiation dose. Specifically, the scintillation material is segmented into a plurality of segments; and a connecting cable for each of the plurality of segments is used for conducting scintillation signals to a scintillation detector.

  6. Scintillator-fiber charged-particle track-imaging detector

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Israel, M. H.; Klarmann, J.

    1983-01-01

    A scintillator-fiber charged-particle track-imaging detector has been developed using a bundle of square cross-section plastic scintillator fiber optics, proximity focused onto an image intensified Charge Injection Device (CID) camera. Detector to beams of 15 MeV protons and relativistic Neon, Manganese, and Gold nuclei have been exposed and images of their tracks are obtained. This paper presents details of the detector technique, properties of the tracks obtained, and range measurements of 15 MeV protons stopping in the fiber bundle.

  7. Design, fabrication, and test of a fast scintillation detector preamplifier

    NASA Astrophysics Data System (ADS)

    Bezboruah, T.; Boruah, K.; Boruah, P. K.

    2002-07-01

    A fast scintillation detector preamplifier is designed, which uses an operational video amplifier (type: LM733). Despite its simplicity, the preamplifier exhibits good noise and speed parameters. The amplifier is specially designed for an extensive air shower experiment [T. Bezboruh, K. Boruah, and P. K. Boruah, Nucl. Instrum. Methods Phys. Res. A 410, 206 (1998); Astropart. Phys. 11, 395 (1999)], Gauhati University, Assam, India. Plastic scintillators and fast photomultiplier tubes are used in the experiment to detect ultra high energy cosmic ray events. Here we report the characteristics of the amplifier including the hardware and its performances in the experiment.

  8. Comparison of light transport-incorporated MCNPX and FLUKA codes in generating organic scintillators responses to neutrons and gamma rays

    NASA Astrophysics Data System (ADS)

    Tajik, M.; Ghal-Eh, N.

    2015-08-01

    The NE102 plastic scintillator response to 137Cs gamma rays and NE213 liquid scintillator response to both mono-energetic and 241Am-Be neutrons have been modeled using FLUKA's EVENTBIN and MCNPX's PTRAC cards. The comparison made in different energy regions confirms that the overall difference is less than 6%.

  9. MIPP Plastic Ball electronics upgrade

    SciTech Connect

    Baldin, Boris; /Fermilab

    2009-01-01

    An upgrade electronics design for Plastic Ball detector is described. The Plastic Ball detector was a part of several experiments in the past and its back portion (proposed to be used in MIPP) consists of 340 photomultipliers equipped with a sandwich scintillator. The scintillator sandwich has fast and slow signal component with decay times 10 ns and 1 {micro}s respectively. The upgraded MIPP experiment will collect up to 12,000 events during each 4 second spill and read them out in {approx}50 seconds between spills. The MIPP data acquisition system will employ deadtime-less concept successfully implemented in Muon Electronics of Dzero experiment at Fermilab. An 8-channel prototype design of the Plastic Ball Front End (PBFE) implementing these requirements is discussed. Details of the schematic design, simulation and prototype test results are discussed.

  10. Incidence of plastic debris in Sooty Tern nests: A preliminary study on Trindade Island, a remote area of Brazil.

    PubMed

    de Souza Petersen, Elisa; Krüger, Lucas; Dezevieski, Alexandre; Petry, MariaVirginia; Montone, Rosalinda Carmela

    2016-04-15

    Plastic is abundant in the oceans, reaching pelagic zones away from continents. Here we present the first recordings of plastic used as nest material in Sooty Tern nests, on a remote oceanic island. We describe our findings in terms of quantity, size and color of plastic debris. A total of 78 plastics were noted in 54 nests. Four color categories were found: Blue, White, Green and Red. Blue fragments were the most frequent color, present three times as much as white debris. This pattern was present despite blue fragments being smaller and lighter. The plastic debris of lowest frequency were the larger and heavier pieces (red). To our knowledge this is the first record of plastic in Sooty Tern nests. Trindade Island is on an oceanic zone expected to accumulate garbage due to the dynamic ocean currents. Such findings call for a closer inspection of pollution in the Atlantic Ocean.

  11. Incidence of plastic debris in Sooty Tern nests: A preliminary study on Trindade Island, a remote area of Brazil.

    PubMed

    de Souza Petersen, Elisa; Krüger, Lucas; Dezevieski, Alexandre; Petry, MariaVirginia; Montone, Rosalinda Carmela

    2016-04-15

    Plastic is abundant in the oceans, reaching pelagic zones away from continents. Here we present the first recordings of plastic used as nest material in Sooty Tern nests, on a remote oceanic island. We describe our findings in terms of quantity, size and color of plastic debris. A total of 78 plastics were noted in 54 nests. Four color categories were found: Blue, White, Green and Red. Blue fragments were the most frequent color, present three times as much as white debris. This pattern was present despite blue fragments being smaller and lighter. The plastic debris of lowest frequency were the larger and heavier pieces (red). To our knowledge this is the first record of plastic in Sooty Tern nests. Trindade Island is on an oceanic zone expected to accumulate garbage due to the dynamic ocean currents. Such findings call for a closer inspection of pollution in the Atlantic Ocean. PMID:26936122

  12. Ceramic thin films on plastics: a versatile transfer process for large area as well as patterned coating.

    PubMed

    Kozuka, Hiromitsu; Fukui, Takafumi; Takahashi, Mitsuru; Uchiyama, Hiroaki; Tsuboi, Shohei

    2012-12-01

    A versatile technique for fabricating ceramic thin films on plastics has been proposed. The technique comprises (i) the deposition of a gel film by spin- or dip-coating on a silicon substrate coated beforehand with a release layer, (ii) the firing of the gel film into a ceramic film, and (iii) its transfer onto plastics by melting or softening the plastics surface. Reflective anatase and electrically conductive indium-tin-oxide (ITO) thin films were prepared on acrylic resin and polycarbonate substrates. Patterned ITO thin films could also be fabricated on plastics by using a mother silicon substrate with periodic grooves. PMID:23211312

  13. Ceramic thin films on plastics: a versatile transfer process for large area as well as patterned coating.

    PubMed

    Kozuka, Hiromitsu; Fukui, Takafumi; Takahashi, Mitsuru; Uchiyama, Hiroaki; Tsuboi, Shohei

    2012-12-01

    A versatile technique for fabricating ceramic thin films on plastics has been proposed. The technique comprises (i) the deposition of a gel film by spin- or dip-coating on a silicon substrate coated beforehand with a release layer, (ii) the firing of the gel film into a ceramic film, and (iii) its transfer onto plastics by melting or softening the plastics surface. Reflective anatase and electrically conductive indium-tin-oxide (ITO) thin films were prepared on acrylic resin and polycarbonate substrates. Patterned ITO thin films could also be fabricated on plastics by using a mother silicon substrate with periodic grooves.

  14. New Structured Scintillators for Neutron Radiography

    NASA Astrophysics Data System (ADS)

    Nagarkar, V. V.; Ovechkina, E. E.; Bhandari, H. B.; Soundara-Pandian, L.; More, M. J.; Riedel, R. A.; Miller, S. R.

    minimized by lowering the film thickness and its neutron sensitivity can be maximized through the use of enriched Gd. The fabrication of micro-structured films of these materials using an evaporation technique permits the cost-effective volume synthesis of high-quality neutron scintillators over large areas (20 cm x 20 cm) in short time. In addition, the vapour deposition permits stoichiometry and dopant control not possible using conventional crystal growth.

  15. Cerium compounds as scintillators

    SciTech Connect

    Wojtowicz, A.J.; Berman, E.; Koepke, C.; Lempicki, A.

    1991-01-01

    Stoichiometric Ce-materials with negligible Ce-Ce interactions should have superior scintillator properties. We present two materials: CeF{sub 3} and Ce{sub x}La{sub 1-x}P{sub 5}O{sub 14}. While cerium trifluoride is a known scintillator, pentaphosphate is of a limited usefulness, except as a remarkable model material. We show that quenching in fluoride is responsible for loss of 50% of the light output and is the cause of the, so-called, ultra fast component (2 ns). Light output of fluoride (about 50% of BGO) could be significantly improved. Deeper understanding of Ce-systems is needed to fully exploit their potentials. 10 figs., 6 refs.

  16. Cerium compounds as scintillators

    SciTech Connect

    Wojtowicz, A.J.; Berman, E.; Koepke, C.; Lempicki, A.

    1991-12-31

    Stoichiometric Ce-materials with negligible Ce-Ce interactions should have superior scintillator properties. We present two materials: CeF{sub 3} and Ce{sub x}La{sub 1-x}P{sub 5}O{sub 14}. While cerium trifluoride is a known scintillator, pentaphosphate is of a limited usefulness, except as a remarkable model material. We show that quenching in fluoride is responsible for loss of 50% of the light output and is the cause of the, so-called, ultra fast component (2 ns). Light output of fluoride (about 50% of BGO) could be significantly improved. Deeper understanding of Ce-systems is needed to fully exploit their potentials. 10 figs., 6 refs.

  17. Composite scintillator screen

    DOEpatents

    Zeman, Herbert D.

    1994-01-01

    A scintillator screen for an X-ray system includes a substrate of low-Z material and bodies of a high-Z material embedded within the substrate. By preselecting the size of the bodies embedded within the substrate, the spacial separation of the bodies and the thickness of the screen, the sensitivity of the screen to X-rays within a predetermined energy range can be predicted.

  18. Scintillator-fiber charged particle track-imaging detector

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Israel, M. H.; Klarmann, J.

    1983-01-01

    A scintillator-fiber charged-particle track-imaging detector was developed using a bundle of square cross section plastic scintillator fiber optics, proximity focused onto an image intensified charge injection device (CID) camera. The tracks of charged particle penetrating into the scintillator fiber bundle are projected onto the CID camera and the imaging information is read out in video format. The detector was exposed to beams of 15 MeV protons and relativistic Neon, Manganese, and Gold nuclei and images of their tracks were obtained. Details of the detector technique, properties of the tracks obtained, and preliminary range measurements of 15 MeV protons stopping in the fiber bundle are presented.

  19. Scintillation counters in modern high-energy physics experiments (Review)

    NASA Astrophysics Data System (ADS)

    Kharzheev, Yu. N.

    2015-07-01

    Scintillation counters (SCs) based on organic plastic scintillators (OPSs) are widely used in modern high-energy physics (HEP) experiments. A comprehensive review is given to technologies for production of OPS strips and tiles (extrusion, injection molding, etc.), optical and physical characteristics of OPSs, and methods of light collection based on the use of wavelength-shifting (WLS) fibers coupled to multipixel vacuum and silicon PMs. Examples are given of the use of SCs in modern experiments involved in the search for quarks and new particles, including the Higgs boson (D0, CDF, ATLAS, CMS), new states of matter (ALICE), CP violation (LHCb, KLOE), neutrino oscillations (MINOS, OPERA), and cosmic particles in a wide mass and energy interval (AMS-02). Scintillation counters hold great promise for future HEP experiments (at the ILC, NICA, FAIR) due to properties of a high segmentation, WLS fiber light collection, and multipixel silicon PMT readout.

  20. Structural design of a high energy particle detector using liquid scintillator

    SciTech Connect

    Berg, Timothy John; /Minnesota U.

    1997-02-01

    This thesis presents a design for a 10,000 ton liquid scintillator neutrino detector being considered for the MINOS project at Fermilab. Details of designing, manufacturing, and assembling the active detector components are presented. The detector consists of 1080 magnetized steel absorber planes alternating with 1080 active detector planes. Each active plane is made up of plastic extrusions divided into nearly 400 cells for positional resolution. Life tests on the plastic extrusions determine their feasibility for containing the scintillator. The extrusions are sealed at the bottom, filled with liquid scintillator, and have an optical fiber running the entire length of each cell. The fibers terminate at the top of each extrusion in a manifold. An optical-fiber-light-guide connects the fibers in each manifold to a photo-detector. The photo-detector converts the light signals from the scintillator and optical fibers into electrical impulses for computer analysis.

  1. Melt-cast organic glasses as high-efficiency fast neutron scintillators

    NASA Astrophysics Data System (ADS)

    Carlson, Joseph S.; Feng, Patrick L.

    2016-10-01

    In this work we report a new class of organic-based scintillators that combines several of the desirable attributes of existing crystalline, liquid, and plastic organic scintillators. The prepared materials may be isolated in single crystalline form or melt-cast to produce highly transparent glasses that have been shown to provide high light yields of up to 16,000 photons/MeVee, as evaluated against EJ-200 plastic scintillators and solution-grown trans-stilbene crystals. The prepared organic glasses exhibit neutron/gamma pulse-shape discrimination (PSD) and are compatible with wavelength shifters to reduce optical self-absorption effects that are intrinsic to pure materials such as crystalline organics. The combination of high scintillation efficiency, PSD capabilities, and facile scale-up via melt-casting distinguishes this new class of amorphous materials from existing alternatives.

  2. Melt-cast organic glasses as high-efficiency fast neutron scintillators

    DOE PAGES

    Carlson, Joseph S.; Feng, Patrick L.

    2016-06-24

    In this work we report a new class of organic-based scintillators that combines several of the desirable attributes of existing crystalline, liquid, and plastic organic scintillators. The prepared materials may be isolated in single crystalline form or melt-cast to produce highly transparent glasses that have been shown to provide high light yields of up to 16,000 photons/MeVee, as evaluated against EJ-200 plastic scintillators and solution-grown trans-stilbene crystals. The prepared organic glasses exhibit neutron/gamma pulse-shape discrimination (PSD) and are compatible with wavelength shifters to reduce optical self-absorption effects that are intrinsic to pure materials such as crystalline organics. In conclusion, themore » combination of high scintillation efficiency, PSD capabilities, and facile scale-up via melt-casting distinguishes this new class of amorphous materials from existing alternatives.« less

  3. Lunar components in Lunping scintillations

    SciTech Connect

    Koster, J.R.; Lue, H.Y.; Wu, Hsi-Shu; Huang, Yinn-Nien

    1993-08-01

    The authors report on an anlysis of a 14 year data set of ionospheric scintillation data for 136 MHz signals transmitted from a Japanese satellite. They use a lunar age superposition method to analyze this data, breaking the data into blocks by seasons of the year. They observe a number of different scintillation types in the record, as well as impacts of lunar tides on the time record. They attempt to provide an origin for the different scintillation types.

  4. Selection and screening of microbial consortia for efficient and ecofriendly degradation of plastic garbage collected from urban and rural areas of Bangalore, India.

    PubMed

    Skariyachan, Sinosh; Megha, M; Kini, Meghna Niranjan; Mukund, Kamath Manali; Rizvi, Alya; Vasist, Kiran

    2015-01-01

    Industrialization and urbanization have led to massive accumulation of plastic garbage all over India. The persistence of plastic in soil and aquatic environment has become ecological threat to the metropolitan city such as Bangalore, India. Present study investigates an ecofriendly, efficient and cost-effective approach for plastic waste management by the screening of novel microbial consortia which are capable of degrading plastic polymers. Plastic-contaminated soil and water samples were collected from six hot spots of urban and rural areas of Bangalore. The plastic-degrading bacteria were enriched, and degradation ability was determined by zone of clearance method. The percentage of polymer degradation was initially monitored by weight loss method, and the main isolates were characterized by standard microbiology protocols. These isolates were used to form microbial consortia, and the degradation efficiency of the consortia was compared with individual isolate and known strains obtained from the Microbial Type Culture Collection (MTCC) and Gene Bank, India. One of the main enzymes responsible for polymer degradation was identified, and the biodegradation mechanism was hypothesized by bioinformatics studies. From this study, it is evident that the bacteria utilized the plastic polymer as a sole source of carbon and showed 20-50% weight reduction over a period of 120 days. The two main bacteria responsible for the degradation were microbiologically characterized to be Pseudomonas spp. These bacteria could grow optimally at 37 °C in pH 9.0 and showed 35-40% of plastic weight reduction over 120 days. These isolates were showed better degradation ability than known strains from MTCC. The current study further revealed that the microbial consortia formulated by combining Psuedomonas spp. showed 40 plastic weight reduction over a period of 90 days. Further, extracellular lipase, one of the main enzymes responsible for polymer degradation, was identified. The

  5. Selection and screening of microbial consortia for efficient and ecofriendly degradation of plastic garbage collected from urban and rural areas of Bangalore, India.

    PubMed

    Skariyachan, Sinosh; Megha, M; Kini, Meghna Niranjan; Mukund, Kamath Manali; Rizvi, Alya; Vasist, Kiran

    2015-01-01

    Industrialization and urbanization have led to massive accumulation of plastic garbage all over India. The persistence of plastic in soil and aquatic environment has become ecological threat to the metropolitan city such as Bangalore, India. Present study investigates an ecofriendly, efficient and cost-effective approach for plastic waste management by the screening of novel microbial consortia which are capable of degrading plastic polymers. Plastic-contaminated soil and water samples were collected from six hot spots of urban and rural areas of Bangalore. The plastic-degrading bacteria were enriched, and degradation ability was determined by zone of clearance method. The percentage of polymer degradation was initially monitored by weight loss method, and the main isolates were characterized by standard microbiology protocols. These isolates were used to form microbial consortia, and the degradation efficiency of the consortia was compared with individual isolate and known strains obtained from the Microbial Type Culture Collection (MTCC) and Gene Bank, India. One of the main enzymes responsible for polymer degradation was identified, and the biodegradation mechanism was hypothesized by bioinformatics studies. From this study, it is evident that the bacteria utilized the plastic polymer as a sole source of carbon and showed 20-50% weight reduction over a period of 120 days. The two main bacteria responsible for the degradation were microbiologically characterized to be Pseudomonas spp. These bacteria could grow optimally at 37 °C in pH 9.0 and showed 35-40% of plastic weight reduction over 120 days. These isolates were showed better degradation ability than known strains from MTCC. The current study further revealed that the microbial consortia formulated by combining Psuedomonas spp. showed 40 plastic weight reduction over a period of 90 days. Further, extracellular lipase, one of the main enzymes responsible for polymer degradation, was identified. The

  6. Potential Application of Fabricated Sulfide-Based Scintillation Materials for Radiation Detection

    SciTech Connect

    Im, Hee-Jung; Dai, Sheng; Pawel, Michelle D; Brown, Suree

    2010-01-01

    In our laboratories, we have produced ZnS(Ag)/{sup 6}Li sol-gel scintillation materials which produce an excellent light output with an alpha radiation (compared to commercial high temperature lithiated glass; KG-2 and a plastic scintillator; BC-400). However, when tested with a neutron radiation, the opacity of the ZnS(Ag)/{sup 6}Li sol-gel scintillation materials, which were composed of a homogeneous micron-sized ZnS(Ag), prevented a clear neutron energy peak formation, thus making it difficult to set a threshold for neutron-gamma discrimination. In an effort to increase the transparency of the scintillation materials and to develop new technologies to fabricate sulfide-based scintillation materials for neutron detection, we turned to the methods of a chemical bath deposition (CBD) and a nano-particle synthesis for possible solutions.

  7. Statistical analysis of scintillation data

    SciTech Connect

    Chua, S.; Noonan, J.P.; Basu, S.

    1981-09-01

    The Nakagami-m distribution has traditionally been used successfully to model the probability characteristics of ionospheric scintillations at UHF. This report investigates the distribution properties of scintillation data in the L-band range. Specifically, the appropriateness of the Nakagami-m and lognormal distributions is tested. Briefly the results confirm that the Nakagami-m is appropriate for UHF but not for L-band scintillations. The lognormal provides a better fit to the distribution of L-band scintillations and is an adequate model allowing for an error of + or - 0.1 or smaller in predicted probability with a sample size of 256.

  8. Neutron crosstalk between liquid scintillators

    NASA Astrophysics Data System (ADS)

    Verbeke, J. M.; Prasad, M. K.; Snyderman, N. J.

    2015-09-01

    A method is proposed to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators was modeled to illustrate the improvement of the mass reconstruction.

  9. Neutron crosstalk between liquid scintillators

    SciTech Connect

    Verbeke, J. M.; Prasad, M. K.; Snyderman, N. J.

    2015-05-01

    We propose a method to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators was modeled to illustrate the improvement of the mass reconstruction.

  10. Evaluation of the environmental plasticity in the xerohalophyte Zygophyllum fabago L. for the phytomanagement of mine tailings in semiarid areas.

    PubMed

    Párraga-Aguado, I; González-Alcaraz, M N; López-Orenes, A; Ferrer-Ayala, M A; Conesa, H M

    2016-10-01

    Phytomanagement by phytostabilisation of metal(loid)-enriched mine tailings in semiarid areas has been proposed as a suitable technique to promote a self-sustainable vegetal cover for decreasing the spread of polluted particles by erosion. The goal of this work was to evaluate the contribution of a pioneer plant species (Zygophyllum fabago) in ameliorating the soil conditions at two mine tailings piles located in a semiarid area in Southeast Spain. The ecophysiological performance of this plant species compared to a control population was assessed by analysing the nutritional and ecophysiological status. The presence of Z. fabago in mine tailings enhanced the soil microbial activity and increased the content of soil organic carbon within the rhizosphere (approx. 50% increasing). Metal(loid) concentrations in the tailings may play a minor role in the establishment of Z. fabago plants due to the low metal(loid) availability in the tailings (low CaCl2-extractable concentrations) and low uptake in the plants (e.g. up to 300 mg kg(-1) Zn in leaves). The lower δ(13)C and δ(13)O in the plants sampled at both tailings compared to the control ones may indicate softer stomatal regulation in relation to the control site plants and therefore lower WUE. The Z. fabago plants may skip some energy-demanding mechanisms such as stomatal control and/or proline synthesis to overcome the environmental stresses posed at the tailings. The Z. fabago plants revealed high plasticity of the species for adapting to the low fertility soil conditions of the tailings and to overcome constraints associated to the dry season.

  11. The Use of Scintillation for Astronomical Site Testing

    NASA Astrophysics Data System (ADS)

    Sarazin, M. S.; Tokovinin, A.

    2009-09-01

    When site testing for future astronomical facilities (Extremely Large Telescopes, ELT), teams around the world use scintillation to locate the optically turbulent layers within the atmosphere. Several dedicated instruments are described which have been developed to retrieve the whole vertical Cn2 profile from close to the ground up to about 20km. MASS (Multi Aperture Scintillation Sensor) high altitude profilers in particular, when used in a network, can provide a 3D tracking of clear air turbulence during nighttime over large areas.

  12. Liquid Scintillation Radioassay in Disposable Microcentrifuge Tubes: Radioimmune Precipitates and Other Applications

    PubMed Central

    Schaffer, F. L.; Soergel, M. E.

    1974-01-01

    A simple, economical radioassay system employing disposable polypropylene microcentrifuge tubes was developed. Plastic adapters permitted automatic operation in liquid scintillation spectrometers. Counting efficiencies of 3H, 14C, 32P, and 125I in liquid scintillation cocktails and of 32P by Cerenkov radiation (at lower efficiency in absence of added scintillator) were comparable to those in standard vials. Multipurpose use of the microtubes made the system versatile and expedient, e.g., collection of precipitates and radioassay in the same container. Collection of radioimmune precipitates was aided by a carrier inorganic precipitate, Mg2P2O7. Images PMID:4137041

  13. Characteristics of High-latitude and Equatorial Ionospheric Scintillation of GNSS Signals

    NASA Astrophysics Data System (ADS)

    Morton, Y.; Jiao, Y.

    2014-12-01

    In this paper, several years of multi-constellation global navigation satellite scintillation data collected at Alaska, Peru, and Ascension Island are analyzed to characterize scintillation features observed at high latitude and equatorial locations during the current solar maximum. Recognizing that strong scintillation data are often lost due to the lack of robustness in conventional GPS receivers used for ionosphere scintillation monitoring (ISM), an autonomous event driven scintillation data collection system using software-defined raw RF sampling devices have been developed deployed at a number of strategically selected high latitude and equatorial locations since 2009. This unique scintillation data recording system is triggered by indicators computed from a continuously operating ISM receiver and the raw RF data is post processed using advanced receiver signal processing algorithms designed to minimize carrier phase cycle slips and loss of lock of signals during strong scintillations. Based on scintillation events extracted from the raw data, several statistical distributions are established to characterize the intensity, duration and occurrence frequency of scintillation. Results confirm that scintillation at low latitudes is generally more intense and longer lasting, while high-latitude scintillation is milder and usually dominated by phase fluctuations. Results also reveal the impacts of solar activity, geomagnetic activity and seasons on scintillation in different areas. Combining measurements from a co-located geo-magnetometer and corresponding global geomagnetic activities, qualitative and quantitative correlations between scintillation and both local and global geomagnetic activities have been obtained. Results show that in Alaska, the occurrence frequency and intensity of scintillation, especially phase fluctuations, have strong correlations with geomagnetic field intensity disturbances, while in equatorial stations, the correlation is not obvious.

  14. Lithium-loaded liquid scintillators

    DOEpatents

    Dai, Sheng; Kesanli, Banu; Neal, John S.

    2012-05-15

    The invention is directed to a liquid scintillating composition containing (i) one or more non-polar organic solvents; (ii) (lithium-6)-containing nanoparticles having a size of up to 10 nm and surface-capped by hydrophobic molecules; and (iii) one or more fluorophores. The invention is also directed to a liquid scintillator containing the above composition.

  15. Hybrid scintillators for neutron discrimination

    DOEpatents

    Feng, Patrick L; Cordaro, Joseph G; Anstey, Mitchell R; Morales, Alfredo M

    2015-05-12

    A composition capable of producing a unique scintillation response to neutrons and gamma rays, comprising (i) at least one surfactant; (ii) a polar hydrogen-bonding solvent; and (iii) at least one luminophore. A method including combining at least one surfactant, a polar hydrogen-bonding solvent and at least one luminophore in a scintillation cell under vacuum or an inert atmosphere.

  16. Free liquid scintillation counting bibliography

    SciTech Connect

    1996-12-31

    Packard Instrument Company announces the availability of its newly updated Bibliography of Packard Tri-Carb Liquid Scintillation Analyzers. This unique new booklet lists 628 references in which Packard Tri-Carb{reg_sign} liquid scintillation analyzers have been used in life science, environmental, nuclear power and archaeological measurements. All listings are cross-referenced by radionuclide, specific field of study and author.

  17. Study of silicon photosensor applicability for scintillator detectors

    NASA Astrophysics Data System (ADS)

    Khilya, V. M.; Voronov, S. A.

    2016-02-01

    The aim of the present work is the creation a prototype of anticoincidence system AC for gamma-telescope GAMMA-400. The detectors of AC are developed on the basis of plastic scintillator and silicon photomultipliers. This work is focuses on research of applicability of silicon photomultipliers SiPM by company SensL, type 60000 with BC-408 plastics for the prototype of anticoincidence system detector ACtop. In frame of project the assembly for measuring of the SiPM characteristics such as the linearity, boundary of saturation, the time resolution was developed. The final stage of work was the integration of the prototype of anticoincidence detector.

  18. Area-Specific Alterations of Synaptic Plasticity in the 5XFAD Mouse Model of Alzheimer’s Disease: Dissociation between Somatosensory Cortex and Hippocampus

    PubMed Central

    Crouzin, Nadine; Baranger, Kevin; Cavalier, Mélanie; Marchalant, Yannick; Cohen-Solal, Catherine; Roman, François S.; Khrestchatisky, Michel; Rivera, Santiago; Féron, François; Vignes, Michel

    2013-01-01

    Transgenic mouse models of Alzheimer’s disease (AD) that overproduce the amyloid beta peptide (Aβ) have highlighted impairments of hippocampal long-term synaptic plasticity associated with the progression of the disease. Here we examined whether the characteristics of one of the hallmarks of AD, i.e. Aβ deposition, in both the somatosensory cortex and the hippocampus, correlated with specific losses of synaptic plasticity in these areas. For this, we evaluated the occurrence of long-term potentiation (LTP) in the cortex and the hippocampus of 6-month old 5xFAD transgenic mice that exhibited massive Aβ deposition in both regions but with different features: in cortical areas a majority of Aβ deposits comprised a dense core surrounded by a diffuse corona while such kind of Aβ deposition was less frequently observed in the hippocampus. In order to simultaneously monitor synaptic changes in both areas, we developed a method based on the use of Multi-Electrode Arrays (MEA). When compared with wild-type (WT) mice, basal transmission was significantly reduced in both areas in 5xFAD mice, while short-term synaptic plasticity was unaffected. The induction of long-term changes of synaptic transmission by different protocols revealed that in 5xFAD mice, LTP in the layer 5 of the somatosensory cortex was more severely impaired than LTP triggered in the CA1 area of the hippocampus. We conclude that cortical plasticity is deficient in the 5xFAD model and that this deficit could be correlated with the proportion of diffuse plaques in 5xFAD mice. PMID:24069328

  19. Scintillator based beta batteries

    NASA Astrophysics Data System (ADS)

    Rensing, Noa M.; Tiernan, Timothy C.; Shirwadkar, Urmila; O'Dougherty, Patrick; Freed, Sara; Hawrami, Rastgo; Squillante, Michael R.

    2013-05-01

    Some long-term, remote applications do not have access to conventional harvestable energy in the form of solar radiation (or other ambient light), wind, environmental vibration, or wave motion. Radiation Monitoring Devices, Inc. (RMD) is carrying out research to address the most challenging applications that need power for many months or years and which have undependable or no access to environmental energy. Radioisotopes are an attractive candidate for this energy source, as they can offer a very high energy density combined with a long lifetime. Both large scale nuclear power plants and radiothermal generators are based on converting nuclear energy to heat, but do not scale well to small sizes. Furthermore, thermo-mechanical power plants depend on moving parts, and RTG's suffer from low efficiency. To address the need for compact nuclear power devices, RMD is developing a novel beta battery, in which the beta emissions from a radioisotope are converted to visible light in a scintillator and then the visible light is converted to electrical power in a photodiode. By incorporating 90Sr into the scintillator SrI2 and coupling the material to a wavelength-matched solar cell, we will create a scalable, compact power source capable of supplying milliwatts to several watts of power over a period of up to 30 years. We will present the latest results of radiation damage studies and materials processing development efforts, and discuss how these factors interact to set the operating life and energy density of the device.

  20. Studies of air showers produced by primaries 10(16) eV using a combined scintillation and water-Cerenkov array

    NASA Technical Reports Server (NTRS)

    Brooke, G.; Perrett, J. C.; Watson, A. A.

    1986-01-01

    An array of 8 x 1.0 sq m plastic scintillation counters and 13 water-Cerenkov detectors (1 to 13.5 sq m) were operated at the center of the Haverah Park array to study some features of air showers produced by 10(16) eV primaries. Measurements of the scintillator lateral distribution function, the water-Cerenkov lateral distribution function, and of the distance dependence of the Cerenkov/scintillator ratio are described.

  1. Occurrence and distribution of organophosphorus esters in soils and wheat plants in a plastic waste treatment area in China.

    PubMed

    Wan, Weining; Zhang, Shuzhen; Huang, Honglin; Wu, Tong

    2016-07-01

    This study for the first time reported the occurrence, distribution and concentrations of organophosphate esters (OPEs) in soils caused by plastic waste treatment, as well as their influence on OPE accumulation in wheat (Triticum aestivum L.). Eight OPEs were detected with the total concentrations of 38-1250 ng/g dry weight in the soils from the treatment sites, and tributoxyethyl phosphate and tri(2-chloroethyl) phosphate present as the dominant OPEs. There were similar distribution patterns of OPEs and significant correlations between the total OPE concentrations in the soils from the plastic waste treatment sites with those in the nearby farmlands (P < 0.005), indicating that plastic waste treatment caused the OPE contamination of farmland soils. The uptake and translocation of OPEs by wheat were determined, with OPEs of high hydrophobicity more easily taken up from soils and OPEs with low hydrophobicity more liable to be translocated acropetally.

  2. TH-C-19A-11: Toward An Optimized Multi-Point Scintillation Detector

    SciTech Connect

    Duguay-Drouin, P; Delage, ME; Therriault-Proulx, F; Beddar, S; Beaulieu, L

    2014-06-15

    Purpose: The purpose of this work is to characterize a 2-points mPSDs' optical chain using a spectral analysis to help selecting the optimal components for the detector. Methods: Twenty different 2-points mPSD combinations were built using 4 plastic scintillators (BCF10, BCF12, BCF60, BC430; St-Gobain) and quantum dots (QDs). The scintillator is said to be proximal when near the photodetector, and distal otherwise. A 15m optical fiber (ESKA GH-4001) was coupled to the scintillating component and connected to a spectrometer (Shamrock, Andor and QEPro, OceanOptics). These scintillation components were irradiated at 125kVp; a spectrum for each scintillator was obtained by irradiation of individual scintillator and shielding the second component, thus talking into account light propagation in all components and interfaces. The combined total spectrum was also acquired and involved simultaneous irradiation of the two scintillators for each possible combination. The shape and intensity were characterized. Results: QDs in proximal position absorb almost all the light signal from distal plastic scintillators and emit in its own emission wavelength, with 100% of the signal in the QD range (625–700nm) for the combination BCF12/QD. However, discrimination is possible when QD is in distal position in combination with blue scintillators, total signal being 73% in the blue range (400-550nm) and 27% in QD range. Similar results are obtained with the orange scintillator (BC430). For optimal signal intensity, BCF12 should always be in proximal position, e.g. having 50% more intensity when coupled with BCF60 in distal position (BCF12/BCF60) compared to the BCF60/BCF12 combination. Conclusion: Different combinations of plastic scintillators and QD were built and their emission spectra were studied. We established a preferential order for the scintillating components in the context of an optimized 2-points mPSD. In short, the components with higher wavelength emission spectrum

  3. Proton recoil scintillator neutron rem meter

    DOEpatents

    Olsher, Richard H.; Seagraves, David T.

    2003-01-01

    A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.

  4. Plastic Surgery

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Plastic Surgery KidsHealth > For Teens > Plastic Surgery Print A ... her forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word " ...

  5. Ionospheric scintillation studies

    NASA Technical Reports Server (NTRS)

    Rino, C. L.; Freemouw, E. J.

    1973-01-01

    The diffracted field of a monochromatic plane wave was characterized by two complex correlation functions. For a Gaussian complex field, these quantities suffice to completely define the statistics of the field. Thus, one can in principle calculate the statistics of any measurable quantity in terms of the model parameters. The best data fits were achieved for intensity statistics derived under the Gaussian statistics hypothesis. The signal structure that achieved the best fit was nearly invariant with scintillation level and irregularity source (ionosphere or solar wind). It was characterized by the fact that more than 80% of the scattered signal power is in phase quadrature with the undeviated or coherent signal component. Thus, the Gaussian-statistics hypothesis is both convenient and accurate for channel modeling work.

  6. Smaller, Lower-Power Fast-Neutron Scintillation Detectors

    NASA Technical Reports Server (NTRS)

    Patel, Jagdish; Blaes, Brent

    2008-01-01

    Scintillation-based fast-neutron detectors that are smaller and less power-hungry than mainstream scintillation-based fast-neutron detectors are undergoing development. There are numerous applications for such detectors in monitoring fast-neutron fluxes from nuclear reactors, nuclear materials, and natural sources, both on Earth and in outer space. A particularly important terrestrial application for small, low-power, portable fast-neutron detectors lies in the requirement to scan for nuclear materials in cargo and baggage arriving at international transportation facilities. The present development of miniature, low-power scintillation-based fast-neutron detectors exploits recent advances in the fabrication of avalanche photodiodes (APDs). Basically, such a detector includes a plastic scintillator, typically between 300 and 400 m thick with very thin silver mirror coating on all its faces except the one bonded to an APD. All photons generated from scintillation are thus internally reflected and eventually directed to the APD. This design affords not only compactness but also tight optical coupling for utilization of a relatively large proportion of the scintillation light. The combination of this tight coupling and the avalanche-multiplication gain (typically between 750 and 1,000) of the APD is expected to have enough sensitivity to enable monitoring of a fast-neutron flux as small as 1,000 cm(exp -2)s(exp -1). Moreover, pulse-height analysis can be expected to provide information on the kinetic energies of incident neutrons. It has been estimated that a complete, fully developed fast-neutron detector of this type, would be characterized by linear dimensions of the order of 10 cm or less, a mass of no more than about 0.5 kg, and a power demand of no more than a few watts.

  7. Scintillator materials containing lanthanum fluorides

    DOEpatents

    Moses, William W.

    1991-01-01

    An improved radiation detector containing a crystalline mixture of LaF.sub.3 and CeF.sub.3 as the scintillator element is disclosed. Scintillators made with from 25% to 99.5% LaF.sub.3 and the remainder CeF.sub.3 have been found to provide a balance of good stopping power, high light yield and short decay constant that is equal to or superior to other known scintillator materials, and which may be processed from natural starting materials containing both rare earth elements. The radiation detectors disclosed are favorably suited for use in general purpose detection and in positron emission tomography.

  8. Scintillator materials containing lanthanum fluorides

    DOEpatents

    Moses, W.W.

    1991-05-14

    An improved radiation detector containing a crystalline mixture of LaF[sub 3] and CeF[sub 3] as the scintillator element is disclosed. Scintillators made with from 25% to 99.5% LaF[sub 3] and the remainder CeF[sub 3] have been found to provide a balance of good stopping power, high light yield and short decay constant that is equal to or superior to other known scintillator materials, and which may be processed from natural starting materials containing both rare earth elements. The radiation detectors disclosed are favorably suited for use in general purpose detection and in positron emission tomography. 2 figures.

  9. Optimum design calculations for detectors based on ZnSe(Те,О) scintillators

    NASA Astrophysics Data System (ADS)

    Katrunov, K.; Ryzhikov, V.; Gavrilyuk, V.; Naydenov, S.; Lysetska, O.; Litichevskyi, V.

    2013-06-01

    Light collection in scintillators ZnSe(X), where X is an isovalent dopant, was studied using Monte Carlo calculations. Optimum design was determined for detectors of "scintillator—Si-photodiode" type, which can involve either one scintillation element or scintillation layers of large area made of small-crystalline grains. The calculations were carried out both for determination of the optimum scintillator shape and for design optimization of light guides, on the surface of which the layer of small-crystalline grains is formed.

  10. [AN EXPERIMENTAL STUDY OF THE HISTOLOGICAL FIBRO GENESIS ABILITIES IN THE AREA OF IMPLANTATION OF ALOTRANSPLANTATES APPLYING INTRAABDOMINAL AND PREPERITONEAL PLASTIC SURGERY].

    PubMed

    Ioffe, Y; Shvets, I; Tarasiuk, T; Furmanov, A; Stetsenko, A; Tsura, Y

    2014-12-01

    The histological fibro genesis abilities in the area of implantation of allotransplantates applying intraabdominal and preperitoneal plastic surgery were examined during experimental research. The experiment involved 12 Russian chinchilla rabbits. The animals were spitted into two groups: I group--operated using IPOM methodology (intraperitonealonlaymesh, n = 6) with the installation "Proceed" mesh made by "Ethicon", group II--modeling preperitoneal plastics with the installation of "Ethicon's Ultrapro" mesh (n = 6). After removing the animals from the experiment, the implants with adhering musculo-aponeurotic tissue layer were excised and sent for histological examination. At the same time the severity of the inflammatory process were rated, the composition of the inflammatory infiltrate, germination of the connective tissue through the pores of the prosthesis and neovascularization. Analyzing the research data of histological connective abilities complexes formed in the area of the allotransplants implantation using intra-abdominal and pre-peritoneal plastic during the experiment, we can conclude that intra-abdominal installation of mesh prostheses reduces the severity of inflammatory changes surrounding tissues and reduces the probability of seroma formation in comparison with the placement of the pre-peritoneal implant. PMID:26638474

  11. [AN EXPERIMENTAL STUDY OF THE HISTOLOGICAL FIBRO GENESIS ABILITIES IN THE AREA OF IMPLANTATION OF ALOTRANSPLANTATES APPLYING INTRAABDOMINAL AND PREPERITONEAL PLASTIC SURGERY].

    PubMed

    Ioffe, Y; Shvets, I; Tarasiuk, T; Furmanov, A; Stetsenko, A; Tsura, Y

    2014-12-01

    The histological fibro genesis abilities in the area of implantation of allotransplantates applying intraabdominal and preperitoneal plastic surgery were examined during experimental research. The experiment involved 12 Russian chinchilla rabbits. The animals were spitted into two groups: I group--operated using IPOM methodology (intraperitonealonlaymesh, n = 6) with the installation "Proceed" mesh made by "Ethicon", group II--modeling preperitoneal plastics with the installation of "Ethicon's Ultrapro" mesh (n = 6). After removing the animals from the experiment, the implants with adhering musculo-aponeurotic tissue layer were excised and sent for histological examination. At the same time the severity of the inflammatory process were rated, the composition of the inflammatory infiltrate, germination of the connective tissue through the pores of the prosthesis and neovascularization. Analyzing the research data of histological connective abilities complexes formed in the area of the allotransplants implantation using intra-abdominal and pre-peritoneal plastic during the experiment, we can conclude that intra-abdominal installation of mesh prostheses reduces the severity of inflammatory changes surrounding tissues and reduces the probability of seroma formation in comparison with the placement of the pre-peritoneal implant.

  12. Distance dependent quenching and gamma-ray spectroscopy in tin-loaded polystyrene scintillators

    DOE PAGES

    Feng, Patrick L; Mengesha, Wondwosen; Anstey, Mitchell R.; Cordaro, Joseph Gabriel

    2016-02-01

    In this study, we report the synthesis and inclusion of rationally designed organotin compounds in polystyrene matrices as a route towards plastic scintillators capable of gamma-ray spectroscopy. Tin loading ratios of up to 15% w/w have been incorporated, resulting in photopeak energy resolution values as low as 10.9% for 662 keV gamma-rays. Scintillator constituents were selected based upon a previously reported distance-dependent quenching mechanism. Data obtained using UV-Vis and photoluminescence measurements are consistent with this phenomenon and are correlated with the steric and electronic properties of the respective organotin complexes. We also report fast scintillation decay behavior that is comparablemore » to the quenched scintillators 0.5% trans-stilbene doped bibenzyl and the commercial plastic scintillator BC-422Q-1%. These observations are discussed in the context of practical considerations such as optical transparency, ease-of-preparation/scale-up, and total scintillator cost.« less

  13. Scintillator fiber optic long counter

    DOEpatents

    McCollum, Tom; Spector, Garry B.

    1994-01-01

    A flat response position sensitive neutron detector capable of providing neutron spectroscopic data utilizing scintillator fiber optic filaments embedded in a neutron moderating housing having an open end through which neutrons enter to be detected.

  14. Scintillator fiber optic long counter

    DOEpatents

    McCollum, T.; Spector, G.B.

    1994-03-29

    A flat response position sensitive neutron detector capable of providing neutron spectroscopic data utilizing scintillator fiber optic filaments embedded in a neutron moderating housing having an open end through which neutrons enter to be detected is described. 11 figures.

  15. Neutron crosstalk between liquid scintillators

    DOE PAGES

    Verbeke, J. M.; Prasad, M. K.; Snyderman, N. J.

    2015-05-01

    We propose a method to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators wasmore » modeled to illustrate the improvement of the mass reconstruction.« less

  16. About NICADD extruded scintillating strips

    SciTech Connect

    Dyshkant, A.; Beznosko, D.; Blazey, G.; Chakraborty, D.; Francis, K.; Kubik, D.; Lima, J.G.; Rykalin, V.; Zutshi, v.; Baldina, E.; Bross, A.; Deering, P.; Nebel, T.; Pla-Dalmau, A.; Schellpfeffer, J.; Serritella, C.; Zimmerman, J.; /Fermilab

    2005-04-01

    The results of control measurements of extruded scintillating strip responses to a radioactive source Sr-90 are provided, and details of strip choice, preparation, and method of measurement are included. About four hundred one meter long extruded scintillating strips were measured at four different points. These results were essential for prototyping a tail catcher and muon tracker for a future international electron positron linear collider detector.

  17. Ionospheric Scintillation Effects on GPS

    NASA Astrophysics Data System (ADS)

    Steenburgh, R. A.; Smithtro, C.; Groves, K.

    2007-12-01

    . Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active, although not limited to, a belt encircling the earth within 20 degrees of the geomagnetic equator. As GPS applications and users increases, so does the potential for detrimental impacts from scintillation. We examined amplitude scintillation data spanning seven years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/Americas longitudinal sector at as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K.; in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at one minute resolution. We examine diurnal, seasonal and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

  18. Scintillation Detector for the Measurement of Ultra-Heavy Cosmic Rays on the Super-TIGER Experiment

    NASA Technical Reports Server (NTRS)

    Link, Jason

    2011-01-01

    We discuss the design and construction of the scintillation detectors for the Super-TIGER experiment. Super-TIGER is a large-area (5.4sq m) balloon-borne experiment designed to measure the abundances of cosmic-ray nuclei between Z= 10 and Z=56. It is based on the successful TIGER experiment that flew in Antarctica in 2001 and 2003. Super-TIGER has three layers of scintillation detectors, two Cherenkov detectors and a scintillating fiber hodoscope. The scintillation detector employs four wavelength shifter bars surrounding the edges of the scintillator to collect the light from particles traversing the detector. PMTs are optically coupled at both ends of the bars for light collection. We report on laboratory performance of the scintillation counters using muons. In addition we discuss the design challenges and detector response over this broad charge range including the effect of scintilator saturation.

  19. Coatings For Plastic Optics

    NASA Astrophysics Data System (ADS)

    Schaffer, Robert W.

    1983-11-01

    Over the past decade there has been a tremendous surge of interest in the use of plastic optical elements to supplement or replace glass optics. While the technology of molding and polishing plastic optics has been the chief interest, there has been increasing need for precision coatings for these elements. In some instances these coatings are as critical as the elements themselves. In this paper we will describe the difficulties incurred in coating plastic and some of the many coatings presently available today despite the difficulties encountered. We will then cover the durability aspects of these coatings and lastly, point out some areas to consider when evaluating using plastic instead of glass.

  20. A fast profile monitor with scintillating fiber hodoscopes for high-intensity photon beams

    NASA Astrophysics Data System (ADS)

    Ishikawa, T.; Fujimura, H.; Hamano, H.; Hashimoto, R.; Honda, Y.; Ishida, T.; Kaida, S.; Kanda, H.; Kido, S.; Matsumura, Y.; Miyabe, M.; Mizutani, K.; Nagasawa, I.; Nakamura, A.; Nanbu, K.; Nawa, K.; Ogushi, S.; Shibasaki, Y.; Shimizu, H.; Sugai, H.; Suzuki, K.; Takahashi, K.; Takahashi, S.; Taniguchi, Y.; Tokiyasu, A. O.; Tsuchikawa, Y.; Yamazaki, H.

    2016-03-01

    A fast beam-profile monitor has been developed for high-energy photon beamlines at the Research Center for Electron Photon Science, Tohoku University. The position of the photon converted into an electron-positron pair in a 0.5 mm-thick aluminum plate is measured with two hodoscopes made of scintillating fibers with cross-sections of 3 × 3mm2. Events in which charged particles are produced upstream are rejected with a charge veto plastic scintillator placed in front of the plate, and pair-production events are identified with a trigger plastic scintillator placed behind the plate. The position is determined by a developed logic module with a field-programmable gate array. The dead time for processing an event is 35 ns, and a high data acquisition efficiency (~ 100 %) can be achieved with this monitor for high-intensity photon beams corresponding to 20 MHz tagging signals.

  1. Development of a wavelength-separated type scintillator with optical fiber (SOF) dosimeter to compensate for the Cerenkov radiation effect.

    PubMed

    Ishikawa, Masayori; Nagase, Naomi; Matsuura, Taeko; Hiratsuka, Junichi; Suzuki, Ryusuke; Miyamoto, Naoki; Sutherland, Kenneth Lee; Fujita, Katsuhisa; Shirato, Hiroki

    2015-03-01

    The scintillator with optical fiber (SOF) dosimeter consists of a miniature scintillator mounted on the tip of an optical fiber. The scintillator of the current SOF dosimeter is a 1-mm diameter hemisphere. For a scintillation dosimeter coupled with an optical fiber, measurement accuracy is influenced by signals due to Cerenkov radiation in the optical fiber. We have implemented a spectral filtering technique for compensating for the Cerenkov radiation effect specifically for our plastic scintillator-based dosimeter, using a wavelength-separated counting method. A dichroic mirror was used for separating input light signals. Individual signal counting was performed for high- and low-wavelength light signals. To confirm the accuracy, measurements with various amounts of Cerenkov radiation were performed by changing the incident direction while keeping the Ir-192 source-to-dosimeter distance constant, resulting in a fluctuation of <5%. Optical fiber bending was also addressed; no bending effect was observed for our wavelength-separated SOF dosimeter.

  2. Development of a wavelength-separated type scintillator with optical fiber (SOF) dosimeter to compensate for the Cerenkov radiation effect

    PubMed Central

    Ishikawa, Masayori; Nagase, Naomi; Matsuura, Taeko; Hiratsuka, Junichi; Suzuki, Ryusuke; Miyamoto, Naoki; Sutherland, Kenneth Lee; Fujita, Katsuhisa; Shirato, Hiroki

    2015-01-01

    The scintillator with optical fiber (SOF) dosimeter consists of a miniature scintillator mounted on the tip of an optical fiber. The scintillator of the current SOF dosimeter is a 1-mm diameter hemisphere. For a scintillation dosimeter coupled with an optical fiber, measurement accuracy is influenced by signals due to Cerenkov radiation in the optical fiber. We have implemented a spectral filtering technique for compensating for the Cerenkov radiation effect specifically for our plastic scintillator-based dosimeter, using a wavelength-separated counting method. A dichroic mirror was used for separating input light signals. Individual signal counting was performed for high- and low-wavelength light signals. To confirm the accuracy, measurements with various amounts of Cerenkov radiation were performed by changing the incident direction while keeping the Ir-192 source-to-dosimeter distance constant, resulting in a fluctuation of <5%. Optical fiber bending was also addressed; no bending effect was observed for our wavelength-separated SOF dosimeter. PMID:25618136

  3. SCINTILLATOR COMPOSITION FOR COUNTERS AND METHOD OF MAKING

    DOEpatents

    Buck, W.L.; Swank, R.K.

    1958-02-25

    This patent deals with a new composition for plastic scintillators and the method of making them. This is accomplished by mixing a solvent, selected from the group consisting of styrene, methylstyrene where the methyl group is attached to the ring, and p-vinylbiphenyl with p-terphenyl as a primary fluor. Marked improvement in the fluorescent properties of this scintillator composition is obtained by incorporating as a second fluor, a small amount of a highly conjugated hydrocarbon having four phenyl groups such as quaterphenyl or 1,1,4,4- tetraphenyl-1,3-butadiene. It is advisable to use very pure monomers in this composition, and to carry out its preparation in the absence of air.

  4. Large-Area Liquid Scintillation Detector Slab

    NASA Astrophysics Data System (ADS)

    Crouch, M. F.; Gurr, H. S.; Hruschka, A. A.; Jenkins, T. L.; Kropp, W. P.; Reines, P.; Sobel, H.

    The following sections are included: * SUMMARY * INTRODUCTION * DETECTOR RESPONSE FUNCTION F(z) AND EVENT POSITION DETERMINATION * REFINEMENTS IN THE DETECTOR CONFIGURATION DESIGN * DETECTOR PERFORMANCE * APPENDIX * REFERENCES

  5. Polybrominated diphenyl ethers (PBDEs) and heavy metals in road dusts from a plastic waste recycling area in north China: implications for human health.

    PubMed

    Tang, Zhenwu; Huang, Qifei; Yang, Yufei; Nie, Zhiqiang; Cheng, Jiali; Yang, Jun; Wang, Yuwen; Chai, Miao

    2016-01-01

    Road dusts were collected from an area where intense mechanical recycling of plastic wastes occurs in Wen'an, north China. These dusts were investigated for polybrominated diphenyl ethers (PBDEs) and heavy metals contamination to assess the health risk related to these components. Decabromodiphenyl ether (BDE-209) and Σ21PBDE concentrations in these dusts ranged from 2.67 to 10,424 ng g(-1) and from 3.23 to 10,640 ng g(-1), respectively. These PBDE concentrations were comparable to those observed in road dust from e-waste recycling areas but were 1-2 orders of magnitude higher than concentrations in outdoor or road dusts from other areas. This indicates that road dusts in the study area have high levels of PBDE pollution. BDE-209 was the predominant congener, accounting for 86.3% of the total PBDE content in dusts. Thus, commercial deca-BDE products were the dominant source. The average concentrations of As, Cd, Cr, Cu, Hg, Pb, Sb, and Zn in these same dust samples were 10.1, 0.495, 112, 54.7, 0.150, 71.8, 10.6, and 186 mg kg(-1), respectively. The geoaccumulation index suggests that road dusts in this area are moderately to heavily polluted with Cd, Hg, and Sb. This study shows that plastic waste processing is a major source of toxic pollutants in road dusts in this area. Although the health risk from exposure to dust PBDEs was low, levels of some heavy metals in this dust exceeded acceptable risk levels for children and are of great concern.

  6. Polybrominated diphenyl ethers (PBDEs) and heavy metals in road dusts from a plastic waste recycling area in north China: implications for human health.

    PubMed

    Tang, Zhenwu; Huang, Qifei; Yang, Yufei; Nie, Zhiqiang; Cheng, Jiali; Yang, Jun; Wang, Yuwen; Chai, Miao

    2016-01-01

    Road dusts were collected from an area where intense mechanical recycling of plastic wastes occurs in Wen'an, north China. These dusts were investigated for polybrominated diphenyl ethers (PBDEs) and heavy metals contamination to assess the health risk related to these components. Decabromodiphenyl ether (BDE-209) and Σ21PBDE concentrations in these dusts ranged from 2.67 to 10,424 ng g(-1) and from 3.23 to 10,640 ng g(-1), respectively. These PBDE concentrations were comparable to those observed in road dust from e-waste recycling areas but were 1-2 orders of magnitude higher than concentrations in outdoor or road dusts from other areas. This indicates that road dusts in the study area have high levels of PBDE pollution. BDE-209 was the predominant congener, accounting for 86.3% of the total PBDE content in dusts. Thus, commercial deca-BDE products were the dominant source. The average concentrations of As, Cd, Cr, Cu, Hg, Pb, Sb, and Zn in these same dust samples were 10.1, 0.495, 112, 54.7, 0.150, 71.8, 10.6, and 186 mg kg(-1), respectively. The geoaccumulation index suggests that road dusts in this area are moderately to heavily polluted with Cd, Hg, and Sb. This study shows that plastic waste processing is a major source of toxic pollutants in road dusts in this area. Although the health risk from exposure to dust PBDEs was low, levels of some heavy metals in this dust exceeded acceptable risk levels for children and are of great concern. PMID:26330321

  7. Predicting the sensitivity of the beryllium/scintillator layer neutron detector using Monte Carlo and experimental response functions

    SciTech Connect

    Styron, J. D. Cooper, G. W.; Carpenter, Ken; Bonura, M. A.; Ruiz, C. L.; Hahn, K. D.; Chandler, G. A.; Nelson, A. J.; Torres, J. A.; McWatters, B. R.

    2014-11-15

    A methodology for obtaining empirical curves relating absolute measured scintillation light output to beta energy deposited is presented. Output signals were measured from thin plastic scintillator using NIST traceable beta and gamma sources and MCNP5 was used to model the energy deposition from each source. Combining the experimental and calculated results gives the desired empirical relationships. To validate, the sensitivity of a beryllium/scintillator-layer neutron activation detector was predicted and then exposed to a known neutron fluence from a Deuterium-Deuterium fusion plasma (DD). The predicted and the measured sensitivity were in statistical agreement.

  8. Effects of developmental exposure to TiO2 nanoparticles on synaptic plasticity in hippocampal dentate gyrus area: an in vivo study in anesthetized rats.

    PubMed

    Gao, Xiaoyan; Yin, Shuting; Tang, Mingliang; Chen, Jutao; Yang, Zhongfei; Zhang, Wencai; Chen, Liang; Yang, Bo; Li, Zhifeng; Zha, Yingying; Ruan, Diyun; Wang, Ming

    2011-12-01

    With the increasing applications of titanium dioxide nanoparticles (TiO(2) NPs) in industry and daily life, an increasing number of studies showed that TiO(2) NPs may have negative effects on the respiratory or metabolic circle systems of organisms, while very few studies focused on the brain central nervous system (CNS). Synaptic plasticity in hippocampus is believed to be associated with certain high functions of CNS, such as learning and memory. Thus, in this study, we investigated the effects of developmental exposure to TiO(2) NPs on synaptic plasticity in rats' hippocampal dentate gyrus (DG) area using in vivo electrophysiological recordings. The input/output (I/O) functions, paired-pulse reaction (PPR), field excitatory postsynaptic potential, and population spike amplitude were measured. The results showed that the I/O functions, PPR, and long-term potentiation were all attenuated in lactation TiO(2) NPs-exposed offspring rats compared with those in the control group. However, in the pregnancy TiO(2) NPs exposure group, only PPR was attenuated significantly. These findings suggest that developmental exposure to TiO(2) NPs could affect synaptic plasticity in offspring's hippocampal DG area in vivo, which indicates that developmental brains, especially in lactation, are susceptible to TiO(2) NPs exposure. This study reveals the potential toxicity of TiO(2) NPs in CNS. It may give some hints on the security of TiO(2) NPs production and application and shed light on its future toxicological studies. PMID:21331565

  9. A decametric wavelength radio telescope for interplanetary scintillation observations

    NASA Technical Reports Server (NTRS)

    Cronyn, W. M.; Shawhan, S. D.

    1975-01-01

    A phased array, electrically steerable radio telescope (with a total collecting area of 18 acres), constructed for the purpose of remotely sensing electron density irregularity structure in the solar wind, is presented. The radio telescope is able to locate, map, and track large scale features of the solar wind, such as streams and blast waves, by monitoring a large grid of natural radio sources subject to rapid intensity fluctuation (interplanetary scintillation) caused by the irregularity structure. Observations verify the performance of the array, the receiver, and the scintillation signal processing circuitry of the telescope.

  10. Radiopure metal-loaded liquid scintillator

    SciTech Connect

    Rosero, Richard; Yeh, Minfang

    2015-08-17

    Metal-loaded liquid scintillator plays a key role in particle and nuclear physics experiments. The applications of metal ions in various neutrino experiments and the purification methods for different scintillator components are discussed in this paper.

  11. Radiopure Metal-Loaded Liquid Scintillator

    SciTech Connect

    Rosero, Richard; Yeh, Minfang

    2015-03-18

    Metal-loaded liquid scintillator plays a key role in particle and nuclear physics experiments. The applications of metal ions in various neutrino experiments and the purification methods for different scintillator components are discussed in this paper.

  12. Unitary scintillation detector and system

    DOEpatents

    McElhaney, S.A.; Chiles, M.M.

    1994-05-31

    The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations. 10 figs.

  13. Unitary scintillation detector and system

    DOEpatents

    McElhaney, Stephanie A.; Chiles, Marion M.

    1994-01-01

    The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations.

  14. Scintillation at two optical frequencies.

    PubMed

    Hubbard, W B; Reitsema, H J

    1981-09-15

    Stellar scintillation data were obtained on a single night at a variety of zenith distances and azimuths, using a photon-counting photometer recording at 100 Hz simultaneously at wavelengths of 0.475 microm and 0.870 microm. Orientable apertures of 42-cm diam separated by 1 m were used to establish the average upper atmosphere wind direction and velocity. Dispersion in the earth's atmosphere separate the average optical paths at the two wavelengths, permitting a reconstruction of the spatial cross-correlation function for scintillations, independent of assumptions about differential fluid motions. Although there is clear evidence of a complicated velocity field, scintillation power was predominantly produced by levels at pressures of 130 +/- 30 mbar. The data are not grossly inconsistent with layers of isotropic Kolmogorov turbulence, but there is some evidence for deviation from the Kolmogorov spectral index and/or anisotropy.

  15. Fracture-resistant lanthanide scintillators

    DOEpatents

    Doty, F. Patrick

    2011-01-04

    Lanthanide halide alloys have recently enabled scintillating gamma ray spectrometers comparable to room temperature semiconductors (<3% FWHM energy resolutions at 662 keV). However brittle fracture of these materials upon cooling hinders the growth of large volume crystals. Efforts to improve the strength through non-lanthanide alloy substitution, while preserving scintillation, have been demonstrated. Isovalent alloys having nominal compositions of comprising Al, Ga, Sc, Y, and In dopants as well as aliovalent alloys comprising Ca, Sr, Zr, Hf, Zn, and Pb dopants were prepared. All of these alloys exhibit bright fluorescence under UV excitation, with varying shifts in the spectral peaks and intensities relative to pure CeBr.sub.3. Further, these alloys scintillate when coupled to a photomultiplier tube (PMT) and exposed to .sup.137Cs gamma rays.

  16. Scintillation-Hardened GPS Receiver

    NASA Technical Reports Server (NTRS)

    Stephens, Donald R.

    2015-01-01

    CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed.

  17. High Latitude Scintillations during the ICI-4 Rocket Campaign.

    NASA Astrophysics Data System (ADS)

    Patra, S.; Moen, J.

    2015-12-01

    We present the first results from the Norwegian ICI-4 sounding rocket campaign in February 2015. The ICI-4 was launched into F-region auroral blobs from the Andøya Space Center. The multi needle langmuir probe (m-NLP) on board the rocket sampled the ionospheric density structures at a sub-meter spatial resolution. A multi-phase screen model has been developed to estimate the scintillations from the density measurements acquired on-board spacecrafts. The phase screen model is validated and the comparison of the estimated values with scintillations measured by ground receivers during the campaign will be presented. A combination of scintillation receivers in Svalbard and surrounding areas as well as all sky imagers at Ny Ålesund, Longyerbyen, and Skibotn are used to improve the performance of the model.

  18. Plastic Jellyfish.

    ERIC Educational Resources Information Center

    Moseley, Christine

    2000-01-01

    Presents an environmental science activity designed to enhance students' awareness of the hazards of plastic waste for wildlife in aquatic environments. Discusses how students can take steps to reduce the effects of plastic waste. (WRM)

  19. Three-dimensional printing of scintillating materials.

    PubMed

    Mishnayot, Y; Layani, M; Cooperstein, I; Magdassi, S; Ron, G

    2014-08-01

    We demonstrate, for the first time, the applicability of three-dimensional printing techniques to the manufacture of scintillation detectors. We report on the development of a formulation, usable in stereolithographic printing, that exhibits scintillation efficiency on the order of 30% of that of commercial polystyrene based scintillators. We discuss the applicability of these techniques and propose future enhancements that will allow tailoring the printed scintillation detectors to various applications.

  20. Nanophosphor composite scintillator with a liquid matrix

    DOEpatents

    McKigney, Edward Allen; Burrell, Anthony Keiran; Bennett, Bryan L.; Cooke, David Wayne; Ott, Kevin Curtis; Bacrania, Minesh Kantilal; Del Sesto, Rico Emilio; Gilbertson, Robert David; Muenchausen, Ross Edward; McCleskey, Thomas Mark

    2010-03-16

    An improved nanophosphor scintillator liquid comprises nanophosphor particles in a liquid matrix. The nanophosphor particles are optionally surface modified with an organic ligand. The surface modified nanophosphor particle is essentially surface charge neutral, thereby preventing agglomeration of the nanophosphor particles during dispersion in a liquid scintillator matrix. The improved nanophosphor scintillator liquid may be used in any conventional liquid scintillator application, including in a radiation detector.

  1. Hygroscopicity Evaluation of Halide Scintillators

    SciTech Connect

    Zhuravleva, M; Stand, L; Wei, H; Hobbs, C. L.; Boatner, Lynn A; Ramey, Joanne Oxendine; Burger, Arnold; Rowe, E; Bhattacharya, P.; Tupitsyn, E; Melcher, Charles L

    2014-01-01

    A collaborative study of relative hygroscopicity of anhydrous halide scintillators grown at various laboratories is presented. We have developed a technique to evaluate moisture sensitivity of both raw materials and grown crystals, in which the moisture absorption rate is measured using a gravimetric analysis. Degradation of the scintillation performance was investigated by recording gamma-ray spectra and monitoring the photopeak position, count rate and energy resolution. The accompanying physical degradation of the samples exposed to ambient atmosphere was photographically recorded as well. The results were compared with ben

  2. Distributions of energy storage rate and microstructural evolution in the area of plastic strain localization during uniaxial tension of austenitic steel

    NASA Astrophysics Data System (ADS)

    Oliferuk, W.; Maj, M.

    2015-08-01

    The presented work is devoted to an experimental determination of the energy storage rate in the area of strain localization. The experimental procedure involves two complementary techniques: i.e. infrared thermography (IRT) and visible light imaging. The results of experiments have shown that during the evolution of plastic strain localization the energy storage rate in some areas of the deformed specimen drops to zero. To interpret the decrease of the energy storage rate in terms of micro-mechanisms, microstructural observations using Transmission Electron Microscopy (TEM) and Electron Back Scattered Diffraction (EBSC) were performed. On the basis of microstructural studies it is believed that a 0 value of energy storage rate corresponds to the state in which only two dominant components of the texture appear, creating conditions for crystallographic shear banding.

  3. Composite scintillators for detection of ionizing radiation

    DOEpatents

    Dai, Sheng [Knoxville, TN; Stephan, Andrew Curtis [Knoxville, TN; Brown, Suree S [Knoxville, TN; Wallace, Steven A [Knoxville, TN; Rondinone, Adam J [Knoxville, TN

    2010-12-28

    Applicant's present invention is a composite scintillator having enhanced transparency for detecting ionizing radiation comprising a material having optical transparency wherein said material comprises nano-sized objects having a size in at least one dimension that is less than the wavelength of light emitted by the composite scintillator wherein the composite scintillator is designed to have selected properties suitable for a particular application.

  4. Photonic crystal scintillators and methods of manufacture

    SciTech Connect

    Torres, Ricardo D.; Sexton, Lindsay T.; Fuentes, Roderick E.; Cortes-Concepcion, Jose

    2015-08-11

    Photonic crystal scintillators and their methods of manufacture are provided. Exemplary methods of manufacture include using a highly-ordered porous anodic alumina membrane as a pattern transfer mask for either the etching of underlying material or for the deposition of additional material onto the surface of a scintillator. Exemplary detectors utilizing such photonic crystal scintillators are also provided.

  5. A new compact neutron/gamma ray scintillation detector

    NASA Astrophysics Data System (ADS)

    Buffler, A.; Comrie, A. C.; Smit, F. D.; Wörtche, H. J.

    2016-09-01

    Progress towards the realization of a new compact neutron spectrometer is described. The detector is based on EJ299-33 plastic scintillator coupled to silicon photomultipliers, and a digital implementation of pulse shape discrimination is used to separate events associated with neutrons from those associated with gamma rays. The spectrometer will be suitable over the neutron energy range 1-100 MeV, illustrated in this work with measurements made using an AmBe radioisotopic source and quasi-monoenergetic neutron beams produced using a cyclotron.

  6. [Effect of plastic film mulching on soil microbial biomass in spring wheat field in semi-arid loess area].

    PubMed

    Song, Qiuhua; Li, Fengmin; Liu, Hongsheng; Wang, Jun; Li, Shiqing

    2003-09-01

    This paper studied the effect of different periods of plastic film mulching (M0-no mulching, M30-mulching for 30 days, M60-mulching for 60 days, and M-mulching for whole growth period) on soil microbial biomass carbon (SMBC) of spring wheat field in semi-arid loess plateau. The mean SMBC in 1999 and 2000 was 335.3 and 259.3 mg.kg-1 dry soil, respectively. It was 29.3% higher in 1999 than in 2000. The highest SMBC was recorded at the harvest stage in M treatment for the two years. In 1999, a wet year with more rainfall, the SMBC of M60 and M treatments was significantly higher than those of M0 and M30 in the mid-period of growth, reached its top at the end of the growth period. The highest grain yield was also achieved in M60. It was a dry year in 2000, but rainfall was rich in the latter growth period of spring wheat. SMBC increased at the beginning period of growth, and did not increase during the mid-growth period. It increased again during the latter period of growth, and showed a significant difference among the treatments. At the harvest stage of 2000, SMBC in M0 was the highest among all the treatments. It was similar between M and M60, and lower than that of M30. In the two years, the ratio of C/N ranged between 7.732-9.042, being lower than the threshold of 11.3, and the ratio of C/P was 300.8-719.6, being higher than the threshold of 300. The two parameters showed that the increase of SMBC was inhibited because of the competition of soil available nutrients between soil microbes and crops. These indicated that soil organic matter content was so shortage that it became the key factor to restrict crop productivity. Under this condition, increasing crop productivity through the input of chemical fertilizers would conceal the problem of soil degradation, and result in a further decrease of soil quality. A long term plastic film mulching would make the problem more serious.

  7. Use of internal scintillator radioactivity to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

    SciTech Connect

    Bircher, Chad; Shao Yiping

    2012-02-15

    Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 x 1.5 and 2.0 x 2.0 mm{sup 2} cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be used

  8. Characterizing energy dependence and count rate performance of a dual scintillator fiber-optic detector for computed tomography

    SciTech Connect

    Hoerner, Matthew R. Stepusin, Elliott J.; Hyer, Daniel E.; Hintenlang, David E.

    2015-03-15

    Purpose: Kilovoltage (kV) x-rays pose a significant challenge for radiation dosimetry. In the kV energy range, even small differences in material composition can result in significant variations in the absorbed energy between soft tissue and the detector. In addition, the use of electronic systems in light detection has demonstrated measurement losses at high photon fluence rates incident to the detector. This study investigated the feasibility of using a novel dual scintillator detector and whether its response to changes in beam energy from scatter and hardening is readily quantified. The detector incorporates a tissue-equivalent plastic scintillator and a gadolinium oxysulfide scintillator, which has a higher sensitivity to scatter x-rays. Methods: The detector was constructed by coupling two scintillators: (1) small cylindrical plastic scintillator, 500 μm in diameter and 2 mm in length, and (2) 100 micron sheet of gadolinium oxysulfide 500 μm in diameter, each to a 2 m long optical fiber, which acts as a light guide to transmit scintillation photons from the sensitive element to a photomultiplier tube. Count rate linearity data were obtained from a wide range of exposure rates delivered from a radiological x-ray tube by adjusting the tube current. The data were fitted to a nonparalyzable dead time model to characterize the time response. The true counting rate was related to the reference free air dose air rate measured with a 0.6 cm{sup 3} Radcal{sup ®} thimble chamber as described in AAPM Report No. 111. Secondary electron and photon spectra were evaluated using Monte Carlo techniques to analyze ionization quenching and photon energy-absorption characteristics from free-in-air and in phantom measurements. The depth/energy dependence of the detector was characterized using a computed tomography dose index QA phantom consisting of nested adult head and body segments. The phantom provided up to 32 cm of acrylic with a compatible 0.6 cm{sup 3} calibrated

  9. Novel scintillators and silicon photomultipliers for nuclear physics and applications

    NASA Astrophysics Data System (ADS)

    Jenkins, David

    2015-06-01

    Until comparatively recently, scintillator detectors were seen as an old-fashioned tool of nuclear physics with more attention being given to areas such as gamma-ray tracking using high-purity germanium detectors. Next-generation scintillator detectors, such as lanthanum bromide, which were developed for the demands of space science and gamma- ray telescopes, are found to have strong applicability to low energy nuclear physics. Their excellent timing resolution makes them very suitable for fast timing measurements and their much improved energy resolution compared to conventional scintillators promises to open up new avenues in nuclear physics research which were presently hard to access. Such "medium-resolution" spectroscopy has broad interest across several areas of contemporary interest such as the study of nuclear giant resonances. In addition to the connections to space science, it is striking that the demands of contemporary medical imaging have strong overlap with those of experimental nuclear physics. An example is the interest in PET-MRI combined imaging which requires putting scintillator detectors in a high magnetic field environment. This has led to strong advances in the area of silicon photomultipliers, a solid-state replacement for photomultiplier tubes, which are insensitive to magnetic fields. Broad application to nuclear physics of this technology may be foreseen.

  10. SNO+ Scintillator Purification and Assay

    NASA Astrophysics Data System (ADS)

    Ford, R.; Chen, M.; Chkvorets, O.; Hallman, D.; Vázquez-Jáuregui, E.

    2011-04-01

    We describe the R&D on the scintillator purification and assay methods and technology for the SNO+ neutrino and double-beta decay experiment. The SNO+ experiment is a replacement of the SNO heavy water with liquid scintillator comprised of 2 g/L PPO in linear alkylbenzene (LAB). During filling the LAB will be transported underground by rail car and purified by multi-stage distillation and steam stripping at a flow rate of 19 LPM. While the detector is operational the scintillator can be recirculated at 150 LPM (full detector volume in 4 days) to provide repurification as necessary by either water extraction (for Ra, K, Bi) or by functional metal scavenger columns (for Pb, Ra, Bi, Ac, Th) followed by steam stripping to remove noble gases and oxygen (Rn, O2, Kr, Ar). The metal scavenger columns also provide a method for scintillator assay for ex-situ measurement of the U and Th chain radioactivity. We have developed "natural" radioactive spikes of Pb and Ra in LAB and use these for purification testing. Lastly, we present the planned operating modes and purification strategies and the plant specifications and design.

  11. SNO+ Scintillator Purification and Assay

    SciTech Connect

    Ford, R.; Vazquez-Jauregui, E.; Chen, M.; Chkvorets, O.; Hallman, D.

    2011-04-27

    We describe the R and D on the scintillator purification and assay methods and technology for the SNO+ neutrino and double-beta decay experiment. The SNO+ experiment is a replacement of the SNO heavy water with liquid scintillator comprised of 2 g/L PPO in linear alkylbenzene (LAB). During filling the LAB will be transported underground by rail car and purified by multi-stage distillation and steam stripping at a flow rate of 19 LPM. While the detector is operational the scintillator can be recirculated at 150 LPM (full detector volume in 4 days) to provide repurification as necessary by either water extraction (for Ra, K, Bi) or by functional metal scavenger columns (for Pb, Ra, Bi, Ac, Th) followed by steam stripping to remove noble gases and oxygen (Rn, O{sub 2}, Kr, Ar). The metal scavenger columns also provide a method for scintillator assay for ex-situ measurement of the U and Th chain radioactivity. We have developed ''natural'' radioactive spikes of Pb and Ra in LAB and use these for purification testing. Lastly, we present the planned operating modes and purification strategies and the plant specifications and design.

  12. Scintillation materials for medical applications

    SciTech Connect

    Lempicki, A.; Wojtowicz, A.J.

    1992-01-01

    Scintillators are beginning to attract renewed attention because modern High Energy Physics accelerators are placing unprecedented demands of quantity and quality of detector materials and Positron Emission Tomography (PET), used by the medical field. Both applications required materials for scintillator detectors with properties beyond those delivered by traditional scintillators. Thallium doped halides are very efficient, but slow and chemically unstable. Two modern developments, namely the very fast BaF[sub 2], which owed its success to the newly discovered crossover transitions, and CeF[sub 3], which carried a promise of fast components, more practical wavelengths and attractive efficiency. Since traditional scintillators (Tl doped halides) are very efficient, and could be even more efficient at larger concentrations of Tl, if it were not for concentration quenching. However Tl transitions are spin forbidden and slow. Both ills could be remedied by replacing Tl with Ce, whose transitions are allowed and which is known to form fully concentrated compounds of high photoluminescent efficiency and no quenching. These materials, plus new Ce-doped materials, exhibiting highly promising properties for medical applications, became the target of our studies.

  13. Method of making a scintillator waveguide

    DOEpatents

    Bliss, Mary; Craig, Richard A.; Reeder, Paul L.

    2000-01-01

    The present invention is an apparatus for detecting ionizing radiation, having: a waveguide having a first end and a second end, the waveguide formed of a scintillator material wherein the therapeutic ionizing radiation isotropically generates scintillation light signals within the waveguide. This apparatus provides a measure of radiation dose. The apparatus may be modified to permit making a measure of location of radiation dose. Specifically, the scintillation material is segmented into a plurality of segments; and a connecting cable for each of the plurality of segments is used for conducting scintillation signals to a scintillation detector.

  14. Plastic, Fantastic? What We Make. Science and Technology Education in Philippine Society.

    ERIC Educational Resources Information Center

    Philippines Univ., Quezon City. Inst. for Science and Mathematics Education Development.

    This module provides information about plastics, focusing on the uses of plastic bags in particular. Topic areas considered include: (1) making plastic bags; (2) transparency of plastic bags; (3) plastic bags and food odors; (4) food containers (before and since plastics); and (5) disposing of plastic bags and other plastic products. The text is…

  15. Energy resolution of scintillation detectors

    NASA Astrophysics Data System (ADS)

    Moszyński, M.; Syntfeld-Każuch, A.; Swiderski, L.; Grodzicka, M.; Iwanowska, J.; Sibczyński, P.; Szczęśniak, T.

    2016-01-01

    According to current knowledge, the non-proportionality of the light yield of scintillators appears to be a fundamental limitation of energy resolution. A good energy resolution is of great importance for most applications of scintillation detectors. Thus, its limitations are discussed below; which arise from the non-proportional response of scintillators to gamma rays and electrons, being of crucial importance to the intrinsic energy resolution of crystals. The important influence of Landau fluctuations and the scattering of secondary electrons (δ-rays) on intrinsic resolution is pointed out here. The study on undoped NaI and CsI at liquid nitrogen temperature with a light readout by avalanche photodiodes strongly suggests that the non-proportionality of many crystals is not their intrinsic property and may be improved by selective co-doping. Finally, several observations that have been collected in the last 15 years on the influence of the slow components of light pulses on energy resolution suggest that more complex processes are taking place in the scintillators. This was observed with CsI(Tl), CsI(Na), ZnSe(Te), and undoped NaI at liquid nitrogen temperature and, finally, for NaI(Tl) at temperatures reduced below 0 °C. A common conclusion of these observations is that the highest energy resolution, and particularly intrinsic resolution measured with the scintillators, characterized by two or more components of the light pulse decay, is obtainable when the spectrometry equipment integrates the whole light of the components. In contrast, the slow components observed in many other crystals degrade the intrinsic resolution. In the limiting case, afterglow could also be considered as a very slow component that spoils the energy resolution. The aim of this work is to summarize all of the above observations by looking for their origin.

  16. Scintillators for positron emission tomography

    SciTech Connect

    Moses, W.W.; Derenzo, S.E.

    1995-09-01

    Like most applications that utilize scintillators for gamma detection, Positron Emission Tomography (PET) desires materials with high light output, short decay time, and excellent stopping power that are also inexpensive, mechanically rugged, and chemically inert. Realizing that this ``ultimate`` scintillator may not exist, this paper evaluates the relative importance of these qualities and describes their impact on the imaging performance of PET. The most important PET scintillator quality is the ability to absorb 511 keV photons in a small volume, which affects the spatial resolution of the camera. The dominant factor is a short attenuation length ({le} 1.5 cm is required), although a high photoelectric fraction is also important (> 30% is desired). The next most important quality is a short decay time, which affects both the dead time and the coincidence timing resolution. Detection rates for single 511 keV photons can be extremely high, so decay times {le} 500 ns are essential to avoid dead time losses. In addition, positron annihilations are identified by time coincidence so {le}5 ns fwhm coincidence pair timing resolution is required to identify events with narrow coincidence windows, reducing contamination due to accidental coincidences. Current trends in PET cameras are toward septaless, ``fully-3D`` cameras, which have significantly higher count rates than conventional 2-D cameras and so place higher demands on scintillator decay time. Light output affects energy resolution, and thus the ability of the camera to identify and reject events where the initial 511 keV photon has undergone Compton scatter in the patient. The scatter to true event fraction is much higher in fully-3D cameras than in 2-D cameras, so future PET cameras would benefit from scintillators with a 511 keV energy resolution < 10--12% fwhm.

  17. Observation of EAS Core with the Small Scintillation Detector at Taro

    NASA Astrophysics Data System (ADS)

    Sakuyama, H.; Kuramochi, Hiroshi; Obara, Hitoshi; Ono, Shunichi; Origasa, Satoru; Mochida, Akinori; Sakayama, Hiroshi; Suzuki, Noboru

    2003-07-01

    We have observed the core structure of extensive air showers(EAS) that primary energy above 1016 eV. To measure the more detail and the correct density of the incident particles near EAS core, we installed 100 small scintillation detectors (using plastic scintillator : 15cm × 15cm × 2.5cm) that are placed on a lattice 10 × 10, and 40cm separation, at Taro Cosmic Ray Lab oratory, at autumn 2002. We report the detail of the small detector, and preliminary results.

  18. Importance of plasticity and local adaptation for coping with changing salinity in coastal areas: a test case with barnacles in the Baltic Sea

    PubMed Central

    2014-01-01

    Background Salinity plays an important role in shaping coastal marine communities. Near-future climate predictions indicate that salinity will decrease in many shallow coastal areas due to increased precipitation; however, few studies have addressed this issue. The ability of ecosystems to cope with future changes will depend on species’ capacities to acclimatise or adapt to new environmental conditions. Here, we investigated the effects of a strong salinity gradient (the Baltic Sea system – Baltic, Kattegat, Skagerrak) on plasticity and adaptations in the euryhaline barnacle Balanus improvisus. We used a common-garden approach, where multiple batches of newly settled barnacles from each of three different geographical areas along the Skagerrak-Baltic salinity gradient were exposed to corresponding native salinities (6, 15 and 30 PSU), and phenotypic traits including mortality, growth, shell strength, condition index and reproductive maturity were recorded. Results We found that B. improvisus was highly euryhaline, but had highest growth and reproductive maturity at intermediate salinities. We also found that low salinity had negative effects on other fitness-related traits including initial growth and shell strength, although mortality was also lowest in low salinity. Overall, differences between populations in most measured traits were weak, indicating little local adaptation to salinity. Nonetheless, we observed some population-specific responses – notably that populations from high salinity grew stronger shells in their native salinity compared to the other populations, possibly indicating adaptation to differences in local predation pressure. Conclusions Our study shows that B. improvisus is an example of a true brackish-water species, and that plastic responses are more likely than evolutionary tracking in coping with future changes in coastal salinity. PMID:25038588

  19. First-principles Electronic Structure Calculations for Scintillation Phosphor Nuclear Detector Materials

    NASA Astrophysics Data System (ADS)

    Canning, Andrew

    2013-03-01

    Inorganic scintillation phosphors (scintillators) are extensively employed as radiation detector materials in many fields of applied and fundamental research such as medical imaging, high energy physics, astrophysics, oil exploration and nuclear materials detection for homeland security and other applications. The ideal scintillator for gamma ray detection must have exceptional performance in terms of stopping power, luminosity, proportionality, speed, and cost. Recently, trivalent lanthanide dopants such as Ce and Eu have received greater attention for fast and bright scintillators as the optical 5d to 4f transition is relatively fast. However, crystal growth and production costs remain challenging for these new materials so there is still a need for new higher performing scintillators that meet the needs of the different application areas. First principles calculations can provide a useful insight into the chemical and electronic properties of such materials and hence can aid in the search for better new scintillators. In the past there has been little first-principles work done on scintillator materials in part because it means modeling f electrons in lanthanides as well as complex excited state and scattering processes. In this talk I will give an overview of the scintillation process and show how first-principles calculations can be applied to such systems to gain a better understanding of the physics involved. I will also present work on a high-throughput first principles approach to select new scintillator materials for fabrication as well as present more detailed calculations to study trapping process etc. that can limit their brightness. This work in collaboration with experimental groups has lead to the discovery of some new bright scintillators. Work supported by the U.S. Department of Homeland Security and carried out under U.S. Department of Energy Contract no. DE-AC02-05CH11231 at Lawrence Berkeley National Laboratory.

  20. Silicon photomultipliers for scintillating trackers

    NASA Astrophysics Data System (ADS)

    Rabaioli, S.; Berra, A.; Bolognini, D.; Bonvicini, V.; Bosisio, L.; Ciano, S.; Iugovaz, D.; Lietti, D.; Penzo, A.; Prest, M.; Rashevskaya, I.; Reia, S.; Stoppani, L.; Vallazza, E.

    2012-12-01

    In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain (∼106). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

  1. LHCb Upgrade: Scintillating Fibre Tracker

    NASA Astrophysics Data System (ADS)

    Tobin, Mark

    2016-07-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  2. Scintillation Monitoring Using Asymmetry Index

    NASA Astrophysics Data System (ADS)

    Shaikh, Muhammad Mubasshir; Mahrous, Ayman; Abdallah, Amr; Notarpietro, Riccardo

    Variation in electron density can have significant effect on GNSS signals in terms of propagation delay. Ionospheric scintillation can be caused by rapid change of such delay, specifically, when they last for a longer period of time. Ionospheric irregularities that account for scintillation may vary significantly in spatial range and drift with the background plasma at speeds of 45 to 130 m/sec. These patchy irregularities may occur several times during night, e.g. in equatorial region, with the patches move through the ray paths of the GNSS satellite signals. These irregularities are often characterized as either ‘large scale’ (which can be as large as several hundred km in East-West direction and many times that in the North-South direction) or ‘small scale’ (which can be as small as 1m). These small scale irregularities are regarded as the main cause of scintillation [1,2]. In normal solar activity conditions, the mid-latitude ionosphere is not much disturbed. However, during severe magnetic storms, the aurora oval extends towards the equator and the equator anomaly region may stretched towards poles extending the scintillation phenomena more typically associated with those regions into mid-latitudes. In such stormy conditions, the predicted TEC may deviate largely from the true value of the TEC both at low and mid-latitudes due to which GNSS applications may be strongly degraded. This work is an attempt to analyze ionospheric scintillation (S4 index) using ionospheric asymmetry index [3]. The asymmetry index is based on trans-ionospheric propagation between GPS and LEO satellites in a radio occultation (RO) scenario, using background ionospheric data provided by MIDAS [4]. We attempted to simulate one of the recent geomagnetic storms (NOAA scale G4) occurred over low/mid-latitudes. The storm started on 26 September 2011 at UT 18:00 and lasted until early hours of 27 September 2011. The scintillation data for the storm was taken from an ionospheric

  3. Detecting scintillations in liquid helium

    NASA Astrophysics Data System (ADS)

    Huffman, P. R.; McKinsey, D. N.

    2013-09-01

    We review our work in developing a tetraphenyl butadiene (TPB)-based detection system for a measurement of the neutron lifetime using magnetically confined ultracold neutrons (UCN). As part of the development of the detection system for this experiment, we studied the scintillation properties of liquid helium itself, characterized the fluorescent efficiencies of different fluors, and built and tested three detector geometries. We provide an overview of the results from these studies as well as references for additional information.

  4. Performance of the first prototype of the CALICE scintillator strip electromagnetic calorimeter

    DOE PAGES

    Francis, K.; Repond, J.; Schlereth, J.; Smith, J.; Xia, L.; Baldolemar, E.; Li, J.; Park, S. T.; Sosebee, M.; White, A. P.; et al

    2014-11-01

    A first prototype of a scintillator strip-based electromagnetic calorimeter was built, consisting of 26 layers of tungsten absorber plates interleaved with planes of 45 × 10 × 3 mm³ plastic scintillator strips. Data were collected using a positron test beam at DESY with momenta between 1 and 6 GeV/c. The prototype's performance is presented in terms of the linearity and resolution of the energy measurement. These results represent an important milestone in the development of highly granular calorimeters using scintillator strip technology. A number of possible design improvements were identified, which should be implemented in a future detector of thismore » type. This technology is being developed for a future linear collider experiment, aiming at the precise measurement of jet energies using particle flow techniques.« less

  5. Performance of the first prototype of the CALICE scintillator strip electromagnetic calorimeter

    SciTech Connect

    Francis, K.; Repond, J.; Schlereth, J.; Smith, J.; Xia, L.; Baldolemar, E.; Li, J.; Park, S. T.; Sosebee, M.; White, A. P.; Yu, J.; Eigen, G.; Mikami, Y.; Watson, N. K.; Thomson, M. A.; Ward, D. R.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Dotti, A.; Folger, G.; Ivantchenko, V.; Ribon, A.; Uzhinskiy, V.; Cârloganu, C.; Gay, P.; Manen, S.; Royer, L.; Tytgat, M.; Zaganidis, N.; Blazey, G. C.; Dyshkant, A.; Lima, J. G.R.; Zutshi, V.; Hostachy, J. -Y.; Morin, L.; Cornett, U.; David, D.; Ebrahimi, A.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Karstensen, S.; Krivan, F.; Krüger, K.; Lutz, B.; Morozov, S.; Morgunov, V.; Neubüser, C.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Garutti, E.; Laurien, S.; Lu, S.; Marchesini, I.; Matysek, M.; Ramilli, M.; Briggl, K.; Eckert, P.; Harion, T.; Schultz-Coulon, H. -Ch.; Shen, W.; Stamen, R.; Bilki, B.; Norbeck, E.; Northacker, D.; Onel, Y.; Wilson, G. W.; Kawagoe, K.; Sudo, Y.; Yoshioka, T.; Dauncey, P. D.; Wing, M.; Salvatore, F.; Cortina Gil, E.; Mannai, S.; Baulieu, G.; Calabria, P.; Caponetto, L.; Combaret, C.; Della Negra, R.; Grenier, G.; Han, R.; Ianigro, J. -C.; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Petrukhin, A.; Steen, A.; Tromeur, W.; Vander Donckt, M.; Zoccarato, Y.; Calvo Alamillo, E.; Fouz, M. -C.; Puerta-Pelayo, J.; Corriveau, F.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Popov, V.; Rusinov, V.; Tarkovsky, E.; Besson, D.; Buzhan, P.; Ilyin, A.; Kantserov, V.; Kaplin, V.; Karakash, A.; Popova, E.; Tikhomirov, V.; Kiesling, C.; Seidel, K.; Simon, F.; Soldner, C.; Weuste, L.; Amjad, M. S.; Bonis, J.; Callier, S.; Conforti di Lorenzo, S.; Cornebise, P.; Doublet, Ph.; Dulucq, F.; Fleury, J.; Frisson, T.; van der Kolk, N.; Li, H.; Martin-Chassard, G.; Richard, F.; de la Taille, Ch.; Pöschl, R.; Raux, L.; Rouëné, J.; Seguin-Moreau, N.; Anduze, M.; Balagura, V.; Boudry, V.; Brient, J. -C.; Cornat, R.; Frotin, M.; Gastaldi, F.; Guliyev, E.; Haddad, Y.; Magniette, F.; Musat, G.; Ruan, M.; Tran, T. H.; Videau, H.; Bulanek, B.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Belhorma, B.; Ghazlane, H.; Kotera, K.; Ono, H.; Takeshita, T.; Uozumi, S.; Jeans, D.; Chang, S.; Khan, A.; Kim, D. H.; Kong, D. J.; Oh, Y. D.; Götze, M.; Sauer, J.; Weber, S.; Zeitnitz, C.

    2014-11-01

    A first prototype of a scintillator strip-based electromagnetic calorimeter was built, consisting of 26 layers of tungsten absorber plates interleaved with planes of 45 × 10 × 3 mm³ plastic scintillator strips. Data were collected using a positron test beam at DESY with momenta between 1 and 6 GeV/c. The prototype's performance is presented in terms of the linearity and resolution of the energy measurement. These results represent an important milestone in the development of highly granular calorimeters using scintillator strip technology. A number of possible design improvements were identified, which should be implemented in a future detector of this type. This technology is being developed for a future linear collider experiment, aiming at the precise measurement of jet energies using particle flow techniques.

  6. Plastics Technology.

    ERIC Educational Resources Information Center

    Barker, Tommy G.

    This curriculum guide is designed to assist junior high schools industrial arts teachers in planning new courses and revising existing courses in plastics technology. Addressed in the individual units of the guide are the following topics: introduction to production technology; history and development of plastics; safety; youth leadership,…

  7. Morphology of auroral zone radio wave scintillation

    SciTech Connect

    Rino, C.L.; Matthews, S.J.

    1980-08-01

    This paper describes the morphology of midnight sector and morning sector auroral zone scintillation observations made over a two-year period using the Wideband satelite, which is in a sun-synchronous, low-altitude orbit. No definitive seasonal variation was found. The nighttime data showed the highest scintillation ocurrence levels, but significant amounts of morning scintillation were observed. For the most part the scintillation activity followed the general pattern of local magnetic activity. The most prominent feature in the nightime data is a localized amplitude and phase scintillation enhancement at the point where the propagation vector lies within an L shell. A geometrical effect due to a dynamic slab of sheetlike structures in the F region is hypothesized as the source of his enhancement. The data have been sorted by magnetic activity, proximity to local midnight, and season. The general features of the data are in agreement with the accepted morphology of auroral zone scintillation.

  8. Perturbation of the left inferior frontal gyrus triggers adaptive plasticity in the right homologous area during speech production.

    PubMed

    Hartwigsen, Gesa; Saur, Dorothee; Price, Cathy J; Ulmer, Stephan; Baumgaertner, Annette; Siebner, Hartwig R

    2013-10-01

    The role of the right hemisphere in aphasia recovery after left hemisphere damage remains unclear. Increased activation of the right hemisphere has been observed after left hemisphere damage. This may simply reflect a release from transcallosal inhibition that does not contribute to language functions. Alternatively, the right hemisphere may actively contribute to language functions by supporting disrupted processing in the left hemisphere via interhemispheric connections. To test this hypothesis, we applied off-line continuous theta burst stimulation (cTBS) over the left inferior frontal gyrus (IFG) in healthy volunteers, then used functional MRI to investigate acute changes in effective connectivity between the left and right hemispheres during repetition of auditory and visual words and pseudowords. In separate sessions, we applied cTBS over the left anterior IFG (aIFG) or posterior IFG (pIFG) to test the anatomic specificity of the effects of cTBS on speech processing. Compared with cTBS over the aIFG, cTBS over the pIFG suppressed activity in the left pIFG and increased activity in the right pIFG during pseudoword vs. word repetition in both modalities. This effect was associated with a stronger facilitatory drive from the right pIFG to the left pIFG during pseudoword repetition. Critically, response became faster as the influence of the right pIFG on left pIFG increased, indicating that homologous areas in the right hemisphere actively contribute to language function after a focal left hemisphere lesion. Our findings lend further support to the notion that increased activation of homologous right hemisphere areas supports aphasia recovery after left hemisphere damage. PMID:24062469

  9. Perturbation of the left inferior frontal gyrus triggers adaptive plasticity in the right homologous area during speech production.

    PubMed

    Hartwigsen, Gesa; Saur, Dorothee; Price, Cathy J; Ulmer, Stephan; Baumgaertner, Annette; Siebner, Hartwig R

    2013-10-01

    The role of the right hemisphere in aphasia recovery after left hemisphere damage remains unclear. Increased activation of the right hemisphere has been observed after left hemisphere damage. This may simply reflect a release from transcallosal inhibition that does not contribute to language functions. Alternatively, the right hemisphere may actively contribute to language functions by supporting disrupted processing in the left hemisphere via interhemispheric connections. To test this hypothesis, we applied off-line continuous theta burst stimulation (cTBS) over the left inferior frontal gyrus (IFG) in healthy volunteers, then used functional MRI to investigate acute changes in effective connectivity between the left and right hemispheres during repetition of auditory and visual words and pseudowords. In separate sessions, we applied cTBS over the left anterior IFG (aIFG) or posterior IFG (pIFG) to test the anatomic specificity of the effects of cTBS on speech processing. Compared with cTBS over the aIFG, cTBS over the pIFG suppressed activity in the left pIFG and increased activity in the right pIFG during pseudoword vs. word repetition in both modalities. This effect was associated with a stronger facilitatory drive from the right pIFG to the left pIFG during pseudoword repetition. Critically, response became faster as the influence of the right pIFG on left pIFG increased, indicating that homologous areas in the right hemisphere actively contribute to language function after a focal left hemisphere lesion. Our findings lend further support to the notion that increased activation of homologous right hemisphere areas supports aphasia recovery after left hemisphere damage.

  10. Comparisons of COSMIC and C/NOFS GPS Occultation Ionospheric Scintillation Measurements with Ground-based Radar and VHF Measurements

    NASA Astrophysics Data System (ADS)

    Ruggiero, F. H.; Groves, K. M.; Straus, P. R.; Caton, R. G.; Starks, M. J.; Tanyi, K. L.; Verlinden, M.

    2009-12-01

    Ionospheric irregularities are known to cause scintillation of trans-ionospheric radio signals and can affect space-based UHF/VHF communications, causing outages, and degrading GPS accuracy and precision. Current capability for characterizing and predicting ionospheric scintillation utilizes a network of ground-based receivers to detect scintillation and then extrapolate for short-term forecasts. Practical limits on deploying the ground receivers limits the accuracy and spatial coverage one can achieve with this approach. A more global approach is to use a set of space-based satellites equipped with GPS receivers, such as the COSMIC satellite constellation, to measure scintillations observed during so-called occultations with GPS satellites. In this paper the signal-to-noise values of GPS L1 signals received on the COSMIC and C/NOFS satellites for the portions of the occultations that are not affected by the terrestrial atmosphere are examined to help identify areas of ionospheric scintillation. Three years of S4 scintillation index values from COSMIC occultations are compared with near-zenith ground-based VHF S4 scintillation measurements from the AFRL SCIntillation Network Decision Aid (SCINDA) network stations. The data are correlated to ascertain the viability of using space-based scintillation measurements to characterize and predict scintillation to ground-based receivers. Several days of COSMIC and C/NOFS data are compared with each other and the ALTAIR radar located on Kwajalein Atoll, Marshall Islands to examine how occultation geometry affects observed scintillation and also to verify techniques that provide an upper bound on the spatial location of the ionospheric irregularities contributing to scintillations observed in the occultations.

  11. Spacecraft Radio Scintillation and Solar System Exploration

    NASA Technical Reports Server (NTRS)

    Woo, Richard

    1993-01-01

    When a wave propagates through a turbulent medium, scattering by the random refractive index inhomogeneities can lead to a wide variety of phenomena that have been the subject of extensive study. The observed scattering effects include amplitude or intensity scintillation, phase scintillation, angular broadening, and spectral broadening, among others. In this paper, I will refer to these scattering effects collectively as scintillation. Although the most familiar example is probably the twinkling of stars (light wave intensity scintillation by turbulence in the Earth's atmosphere), scintillation has been encountered and investigated in such diverse fields as ionospheric physics, oceanography, radio astronomy, and radio and optical communications. Ever since planetary spacecraft began exploring the solar system, scintillation has appeared during the propagation of spacecraft radio signals through planetary atmospheres, planetary ionospheres, and the solar wind. Early studies of these phenomena were motivated by the potential adverse effects on communications and navigation, and on experiments that use the radio link to conduct scientific investigations. Examples of the latter are radio occultation measurements (described below) of planetary atmospheres to deduce temperature profiles, and the search for gravitational waves. However,these concerns soon gave way to the emergence of spacecraft radio scintillation as a new scientific tool for exploring small-scale dynamics in planetary atmospheres and structure in the solar wind, complementing in situ and other remote sensing spacecraft measurements, as well as scintillation measurements using natural (celestial) radio sources. The purpose of this paper is to briefly describe and review the solar system spacecraft radio scintillation observations, to summarize the salient features of wave propagation analyses employed in interpreting them, to underscore the unique remote sensing capabilities and scientific relevance of

  12. Neutron position-sensitive scintillation detector

    DOEpatents

    Strauss, Michael G.; Brenner, Raul

    1984-01-01

    A device is provided for mapping one- and two-dimensional distributions of neutron-positions in a scintillation detector. The device consists of a lithium glass scintillator coupled by an air gap and a light coupler to an array of photomultipliers. The air gap concentrates light flashes from the scintillator, whereas the light coupler disperses this concentrated light to a predetermined fraction of the photomultiplier tube array.

  13. Radio wave scintillations at equatorial regions

    NASA Technical Reports Server (NTRS)

    Poularikas, A. D.

    1972-01-01

    Radio waves, passing through the atmosphere, experience amplitude and phase fluctuations know as scintillations. A characterization of equatorial scintillation, which has resulted from studies of data recorded primarily in South America and equatorial Africa, is presented. Equatorial scintillation phenomena are complex because they appear to vary with time of day (pre-and postmidnight), season (equinoxes), and magnetic activity. A wider and more systematic geographical coverage is needed for both scientific and engineering purposes; therefore, it is recommended that more observations should be made at earth stations (at low-geomagnetic latitudes) to record equatorial scintillation phenomena.

  14. Divalent fluoride doped cerium fluoride scintillator

    DOEpatents

    Anderson, David F.; Sparrow, Robert W.

    1991-01-01

    The use of divalent fluoride dopants in scintillator materials comprising cerium fluoride is disclosed. The preferred divalent fluoride dopants are calcium fluoride, strontium fluoride, and barium fluoride. The preferred amount of divalent fluoride dopant is less than about two percent by weight of the total scintillator. Cerium fluoride scintillator crystals grown with the addition of a divalent fluoride have exhibited better transmissions and higher light outputs than crystals grown without the addition of such dopants. These scintillators are useful in radiation detection and monitoring applications, and are particularly well suited for high-rate applications such as positron emission tomography (PET).

  15. Waveshifters and Scintillators for Ionizing Radiation Detection

    SciTech Connect

    B.Baumgaugh; J.Bishop; D.Karmgard; J.Marchant; M.McKenna; R.Ruchti; M.Vigneault; L.Hernandez; C.Hurlbut

    2007-12-11

    Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments.

  16. Performance of a lead-scintillation-fiber calorimeter designed as an active beam shield for the VENUS detector

    NASA Astrophysics Data System (ADS)

    Takasaki, Fumihiko; Utsumi, M.; Fukui, T.; Narita, Y.; Hosoda, N.; Hirose, T.; Chiba, M.

    1992-11-01

    We made a cylindrical calorimeter which consisted of plastic scintillating fibers and lead. This calorimeter was designed to serve as an active beam shield for the VENUS detector [1] at the TRISTAN electron-positron collider [2]. This device has been successfully used as a beam background shield and as a luminosity monitor of the VENUS detector.

  17. A modular scintillation camera for use in nuclear medicine

    SciTech Connect

    Milster, T.D.; Arendt, J.; Barrett, H.H.; Easton, R.L.; Rossi, G.R.; Selberg, L.A.; Simpson, R.G.

    1984-02-01

    A ''modular'' scintillation camera is discussed as an alternative to using Anger cameras for gamma-ray imaging in nuclear medicine. Each module is an independent gamma camera and consists of a scintillation crystal, light pipe and mask plane, PMT's, and processing electronics. Groups of modules efficiently image radionuclide distributions by effectively utilizing crystal area. Performance of each module is maximized by using Monte-Carlo computer simulations to determine the optical design of the camera, optimizing the signal processing of the PMT signals using maximum-likelihood (ML) estimators, and incorporating digital lookup tables. Each event is completely processed in 2 ..mu..sec, and FWHM of the PSF over the crystal area is expected to be 3 mm. Both one-dimensional and two-dimensional prototypes are tested for spatial and energy resolution

  18. First observations of SBAS/WAAS scintillations: Using collocated scintillation measurements and all-sky images to study equatorial plasma bubbles

    NASA Astrophysics Data System (ADS)

    Ledvina, B. M.; Makela, J. J.

    2005-07-01

    The first observations of amplitude scintillations on a Space Based Augmentation System (SBAS) satellite signal are presented. The scintillations occurred on the signal transmitted by a Wide Area Augmentation Satellite (WAAS) on 8-9 September 2004 from 2250-0045 LT. The GPS receiver that measured the scintillations is located on Haleakala, Hawaii (geomagnetic: 21.3°N, 271.4°E). With a maximum S4 = 0.35, corresponding to a peak-to-peak SNR variation of 8 dB, the scintillations are relatively weak, which is to be expected for a site poleward of the equatorial anomaly during declining solar conditions. Using a collocated all-sky imager, features of the irregularity structuring in the equatorial plasma bubbles are resolved. The satellite signals scintillate when the ray path intersects the three main bubbles. The scintillation intensity tends to peak near the walls, and decreases slightly in the interior of the bubbles. In this case, the bubbles' leading (east) walls contain smaller-scale-size irregularities than the trailing (west) walls.

  19. Scintillation properties of lead sulfate

    SciTech Connect

    Moses, W.W.; Derenzo, S.E. ); Shlichta, P.J. )

    1991-11-01

    We report on the scintillation properties of lead sulfate (PbSO{sub 4}), a scintillator that show promise as a high energy photon detector. It physical properties are well suited for gamma detection, as its has a density of 6.4 gm/cm{sup 3}, a 1/e attenuation length for 511 keV photons of 1.2 cm, is not affected by air or moisture, and is cut and polished easily. In 99.998% pure PbSO{sub 4} crystals at room temperature excited by 511 keV annihilation photons, the fluorescence decay lifetime contains significant fast components having 1.8 ns (5%) and 19 ns (36%) decay times, but with longer components having 95 ns (36%) and 425 ns (23%) decays times. The peak emission wavelength is 335 nm, which is transmitted by borosilicate glass windowed photomultiplier tubes. The total scintillation light output increases with decreasing temperature fro 3,200 photons/MeV at +45{degrees}C to 4, 900 photons/MeV at room temperature (+25{degrees}C) and 68,500 photons/MeV at {minus}145{degrees}C. In an imperfect, 3 mm cube of a naturally occurring mineral form of PbSO{sub 4} (anglesite) at room temperature, a 511 keV photopeak is seen with a total light output of 60% that BGO. There are significant sample to sample variations of the light output among anglesite samples, so the light output of lead sulfate may improve when large synthetic crystals become available. 10 refs.

  20. Measurement accuracy and Cerenkov removal for high performance, high spatial resolution scintillation dosimetry

    SciTech Connect

    Archambault, Louis; Beddar, A. Sam; Gingras, Luc

    2006-01-15

    With highly conformal radiation therapy techniques such as intensity-modulated radiation therapy, radiosurgery, and tomotherapy becoming more common in clinical practice, the use of these narrow beams requires a higher level of precision in quality assurance and dosimetry. Plastic scintillators with their water equivalence, energy independence, and dose rate linearity have been shown to possess excellent qualities that suit the most complex and demanding radiation therapy treatment plans. The primary disadvantage of plastic scintillators is the presence of Cerenkov radiation generated in the light guide, which results in an undesired stem effect. Several techniques have been proposed to minimize this effect. In this study, we compared three such techniques--background subtraction, simple filtering, and chromatic removal--in terms of reproducibility and dose accuracy as gauges of their ability to remove the Cerenkov stem effect from the dose signal. The dosimeter used in this study comprised a 6-mm{sup 3} plastic scintillating fiber probe, an optical fiber, and a color charge-coupled device camera. The whole system was shown to be linear and the total light collected by the camera was reproducible to within 0.31% for 5-s integration time. Background subtraction and chromatic removal were both found to be suitable for precise dose evaluation, with average absolute dose discrepancies of 0.52% and 0.67%, respectively, from ion chamber values. Background subtraction required two optical fibers, but chromatic removal used only one, thereby preventing possible measurement artifacts when a strong dose gradient was perpendicular to the optical fiber. Our findings showed that a plastic scintillation dosimeter could be made free of the effect of Cerenkov radiation.

  1. Regular Exercise Prevents Sleep Deprivation Associated Impairment of Long-Term Memory and Synaptic Plasticity in The CA1 Area of the Hippocampus

    PubMed Central

    Zagaar, Munder; Dao, An; Levine, Amber; Alhaider, Ibrahim; Alkadhi, Karim

    2013-01-01

    Study Objectives: The present study aimed to investigate the effects of treadmill exercise on sleep deprivation (S-D)-induced impairment of hippocampal dependent long-term memory, late phase long-term potentiation (L-LTP) and its signaling cascade in the cornu ammonis 1 (CA1) area. Experimental Design: Animals were conditioned to run on treadmills for 4 weeks then deprived of sleep for 24 h using the columns-in-water method. We tested the effect of exercise and/or S-D on behavioral performance using a post-learning paradigm in the radial arm water maze (RAWM) and in vivo extracellular recording in the CA1 area. The levels of L-LTP-related molecules in the CA1 area were then assessed both before and after L-LTP induction. Measurements and Results: After 24 h of S-D, spatial long-term memory impairment in the RAWM and L-LTP suppression was prevented by 4 weeks of regular exercise. Regular exercise also restored the S-D-associated decreases in the basal levels of key signaling molecules such as: calcium/calmodulin kinase IV (CaMKIV), mitogen-activated protein kinase (MAPK/ERK), phosphorylated cAMP response element-binding protein (P-CREB) and brain derived neurotrophic factor (BDNF), in the CA1 area. After L-LTP induction, regular exercise also prevented the S-D-induced down regulation of BDNF and P-CREB protein levels. Conclusions: The results suggest that our exercise protocol may prevent 24-h S-D-induced impairments in long-term memory and LTP by preventing deleterious changes in the basal and post-stimulation levels of P-CREB and BDNF associated with S-D. Citation: Zagaar M; Dao A; Levine A; Alhaider I; Alkadhi K. Regular exercise prevents sleep deprivation associated impairment of long-term memory and synaptic plasticity in the CA1 area of the hippocampus. SLEEP 2013;36(5):751-761. PMID:23633758

  2. Scintillator handbook with emphasis on cesium iodide

    NASA Technical Reports Server (NTRS)

    Tidd, J. L.; Dabbs, J. R.; Levine, N.

    1973-01-01

    This report provides a background of reasonable depth and reference material on scintillators in general. Particular attention is paid to the cesium iodide scintillators as used in the High Energy Astronomy Observatory (HEAO) experiments. It is intended especially for use by persons such as laboratory test personnel who need to obtain a working knowledge of these materials and their characteristics in a short time.

  3. Binderless composite scintillator for neutron detection

    DOEpatents

    Hodges, Jason P [Knoxville, TN; Crow, Jr; Lowell, M [Oak Ridge, TN; Cooper, Ronald G [Oak Ridge, TN

    2009-03-10

    Composite scintillator material consisting of a binderless sintered mixture of a Lithium (Li) compound containing .sup.6Li as the neutron converter and Y.sub.2SiO.sub.5:Ce as the scintillation phosphor, and the use of this material as a method for neutron detection. Other embodiments of the invention include various other Li compounds.

  4. Scintillation proximity assay using polymeric membranes

    SciTech Connect

    Mansfield, R.K.

    1992-01-01

    Liquid scintillation counting (LSC) is typically used to quantify electron emitting isotopes. In LSC, radioactive samples are dissolved in an organic fluor solution (scintillation cocktail) to ensure that the label is close enough to the fluor molecules to be detected. Although efficient, scintillation cocktail is neither specific or selective for samples labeled with the same radioisotope. Scintillation cocktail is flammable posing significant health risks to the user and is expensive to purchase and discard. Scintillation Proximity Assay (SPA) is a radioanalytical technique where only those radiochemical entities (RCE's) bound to fluor containing matrices are detected. Only bound RCE's are in close enough proximity the entrapped fluor molecules to induce scintillations. Unbound radioligands are too far removed from the fluor molecules to be detected. The research in this dissertation focused on the development and evaluation of fluor-containing membranes (scintillation proximity membranes, SP membranes) to be used for specific radioanalytical techniques without using scintillation cocktail. Polysulfone and PVC SP membranes prepared in our laboratory were investigated for radioimmunossay (RIA) where only bound radioligand is detected, thereby eliminating the separation step impeding the automation of RIA. These SP membranes performed RIA where the results were nearly identical to commercial SP microbeads. SP membranes functionalized with quaternary ammonium hydroxide moieties were able to trap and quantify [sup 14]CO[sub 2] without using liquid scintillation cocktail. RCE's bound in the pore structure of SP membranes are intimate with the entrapped fluor providing the geometry needed for high detection efficiencies. Absorbent SP membranes were used in radiation surveys and were shown to be as effective as conventional survey techniques using filter paper and scintillation cocktail.

  5. Scintillation Effects on Space Shuttle GPS Data

    NASA Technical Reports Server (NTRS)

    Goodman, John L.; Kramer, Leonard

    2001-01-01

    Irregularities in ionospheric electron density result in variation in amplitude and phase of Global Positioning System (GPS) signals, or scintillation. GPS receivers tracking scintillated signals may lose carrier phase or frequency lock in the case of phase sc intillation. Amplitude scintillation can cause "enhancement" or "fading" of GPS signals and result in loss of lock. Scintillation can occur over the equatorial and polar regions and is a function of location, time of day, season, and solar and geomagnetic activity. Mid latitude regions are affected only very rarely, resulting from highly disturbed auroral events. In the spring of 1998, due to increasing concern about scintillation of GPS signals during the upcoming solar maximum, the Space Shuttle Program began to assess the impact of scintillation on Collins Miniaturized Airborne GPS Receiver (MAGR) units that are to replace Tactical Air Control and Navigation (TACAN) units on the Space Shuttle orbiters. The Shuttle Program must determine if scintillation effects pose a threat to safety of flight and mission success or require procedural and flight rule changes. Flight controllers in Mission Control must understand scintillation effects on GPS to properly diagnose "off nominal" GPS receiver performance. GPS data from recent Space Shuttle missions indicate that the signals tracked by the Shuttle MAGR manifest scintillation. Scintillation is observed as anomalous noise in velocity measurements lasting for up to 20 minutes on Shuttle orbit passes and are not accounted for in the error budget of the MAGR accuracy parameters. These events are typically coincident with latitude and local time occurrence of previously identified equatorial spread F within about 20 degrees of the magnetic equator. The geographic and seasonal history of these events from ground-based observations and a simple theoretical model, which have potential for predicting events for operational purposes, are reviewed.

  6. The improved scintillation crystal lead tungstate scintillation for PET

    NASA Astrophysics Data System (ADS)

    Wan, Youbao; WU, Rurong; Xiao, Linrong; Zhang, Jianxin; Yang, Peizhi; Yan, Hui

    2009-07-01

    As a valuable material for the detecting of γ-ray, PbWO4 and BaF2:PbWO4 crystals were grown by a novel multi-crucible temperature gradient system developed by ourselves. Utilizing a topical partial heating method, this system can form a topical partial high temperature in its hearth. Thus this system could melt raw materials in step by step as requirement. The advantage of this method is that there would be solid obstruct left on the melt in the procedure of the crystal growing up. The left obstruct could prevent the volatilization of the component in the melt. Hence it is helpful for the composition homogenization in the crystal. The system also offers a sustaining device for multi-crucibles and thus it can grow many crystals simultaneity. The optical properties and scintillation properties of the crystals were studied. The results reveal that the ions doping improves the scintillation properties of the crystal. The transmittance spectra show that the transmittance of BaF2:PbWO4 crystals are better than that of PbWO4 crystals. For the PbWO4 crystals, their absorption edge is at 325nm, and their maximum transmittance is 68%. For the BaF2:PbWO4 crystals, their absorption edge is at 325nm and their maximum transmittance is upto76%. The X-ray excited luminescence spectra shows that the luminescence peak is at 420nm for the samples of PbWO4 crystal while the peak is at 430nm for the samples of BaF2:PbWO4 crystal respectively. The luminescence intensity of the samples of BaF2:PbWO4 crystal is about two times than that of PbWO4 crystal. And their peak shape is different for the two kind of crystal. The light yield of BaF2:PbWO4 crystals is about 2.9 times than that of PbWO4 crystal Analyzing these scintillation properties, we find that the VPb 3+ and VO- defects do harm for the optical properties of the crystal. Ions doping method could reduce the defect concentration and improving its illumination performance of the crystal. Specially, the doped F- ions in O2- site can

  7. Nuclear Science Symposium, 23rd, Scintillation and Semiconductor Counter Symposium, 15th, and Nuclear Power Systems Symposium, 8th, New Orleans, La., October 20-22, 1976, Proceedings

    NASA Technical Reports Server (NTRS)

    Wagner, L. J.

    1977-01-01

    The volume includes papers on semiconductor radiation detectors of various types, components of radiation detection and dosimetric systems, digital and microprocessor equipment in nuclear industry and science, and a wide variety of applications of nuclear radiation detectors. Semiconductor detectors of X-rays, gamma radiation, heavy ions, neutrons, and other nuclear particles, plastic scintillator arrays, drift chambers, spark wire chambers, and radiation dosimeter systems are reported on. Digital and analog conversion systems, digital data and control systems, microprocessors, and their uses in scientific research and nuclear power plants are discussed. Large-area imaging and biomedical nucleonic instrumentation, nuclear power plant safeguards, reactor instrumentation, nuclear power plant instrumentation, space instrumentation, and environmental instrumentation are dealt with. Individual items are announced in this issue.

  8. Scintillation fiber array detector for measurement of neutron beam profile

    NASA Astrophysics Data System (ADS)

    Kim, Chong; Hong, Byungsik; Jo, Mihee; Lee, Kyong Sei; Sim, Kwang-Souk

    2009-10-01

    We built and tested a detector to measure the profile of fast-neutron beams delivered by the MC50 cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). The core component of the detector is a 2×46 array of scintillation fibers. The light output of the scintillation fibers is transformed into a current signal by a 46-channel silicon photodiode and digitized by a current-mode signal processor. This scanning device was designed to cover a neutron beam area of 30×32 cm2. The detector was tested in a neutron beam delivered by the MC50 cyclotron at KIRAMS. We demonstrate that the detector can successfully measure the neutron beam profile at various beam currents from 10 to 20 μA. The proposed neutron beam profile detector will be useful, for example, in radiotherapy applications with neutron intensities above 107 Hz/cm2.

  9. Measurement of radiation damage of water-based liquid scintillator and liquid scintillator

    DOE PAGES

    Bignell, L. J.; Diwan, M. V.; Hans, S.; Jaffe, D. E.; Rosero, R.; Vigdor, S.; Viren, B.; Worcester, E.; Yeh, M.; Zhang, C.

    2015-10-19

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of 5% scintillating phase) exhibit light yield reductions of 1.74 ± 0.55 % andmore » 1.31 ± 0.59 % after ≈ 800 Gy of proton dose, respectively. Some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical context, a scintillating phantom used for proton therapy treatment plan verification would exhibit a systematic light yield reduction of approximately 0.1% after a year of operation.« less

  10. Measurement of radiation damage of water-based liquid scintillator and liquid scintillator

    SciTech Connect

    Bignell, L. J.; Diwan, M. V.; Hans, S.; Jaffe, D. E.; Rosero, R.; Vigdor, S.; Viren, B.; Worcester, E.; Yeh, M.; Zhang, C.

    2015-10-19

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of 5% scintillating phase) exhibit light yield reductions of 1.74 ± 0.55 % and 1.31 ± 0.59 % after ≈ 800 Gy of proton dose, respectively. Some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical context, a scintillating phantom used for proton therapy treatment plan verification would exhibit a systematic light yield reduction of approximately 0.1% after a year of operation.

  11. Plastic condoms.

    PubMed

    1968-01-01

    Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly

  12. Lifetime measurements in transitional nuclei by fast electronic scintillation timing

    NASA Astrophysics Data System (ADS)

    Caprio, M. A.; Zamfir, N. V.; Casten, R. F.; Amro, H.; Barton, C. J.; Beausang, C. W.; Cooper, J. R.; Gürdal, G.; Hecht, A. A.; Hutter, C.; Krücken, R.; McCutchan, E. A.; Meyer, D. A.; Novak, J. R.; Pietralla, N.; Ressler, J. J.; Berant, Z.; Brenner, D. S.; Gill, R. L.; Regan, P. H.

    2002-10-01

    A new generation of experiments studying nuclei in spherical-deformed transition regions has been motivated by the introduction of innovative theoretical approaches to the treatment of these nuclei. The important structural signatures in the transition regions, beyond the basic yrast level properties, involve γ-ray transitions between low-spin, non-yrast levels, and so information on γ-ray branching ratios and absolute matrix elements (or level lifetimes) for these transitions is crucial. A fast electronic scintillation timing (FEST) system [H. Mach, R. L. Gill, and M. Moszyński, Nucl. Instrum. Methods A 280, 49 (1989)], making use of BaF2 and plastic scintillation detectors, has been implemented at the Yale Moving Tape Collector for the measurement of lifetimes of states populated in β^ decay. Experiments in the A100 (Pd, Ru) and A150 (Dy, Yb) regions have been carried out, and a few examples will be presented. Supported by the US DOE under grants and contracts DE-FG02-91ER-40609, DE-FG02-88ER-40417, and DE-AC02-98CH10886 and by the German DFG under grant Pi 393/1.

  13. Equatorial scintillations: advances since ISEA-6

    SciTech Connect

    Not Available

    1985-01-01

    Our understanding of the morphology of equatorial scintillations has advanced due to more intensive observations at the equatorial anomaly locations in the different longitude zones. The unmistakable effect of the sunspot cycle in controlling irregularity belt width and electron concentration responsible for strong scintillation in the controlling the magnitude of scintillations has been recognized by interpreting scintillation observations inthe light of realistic models of total electron content at various longitudes. A hypothesis based on the alignment of the solar terminator with the geomagnetic flux tubes as an indicator of enhanced scintillation occurrence and another based on the influence of a transequatorial thermospheric neutral wind have been postulated to describe the observed longitudinal variation. A distinct class of equatorial irregularities known as the bottomside sinusoidal (BSS) type was identified. These irregularities occur in very large patches, sometimes in excess of several thousand kilometers in the E-W direction and are associated with frequency spread on ionograms. Scintillations caused by such irregularities exist only in the VHF band, exhibit Fresnel oscillations in intensity spectra and are found to give rise to extremely long durations (approx. several hours) of uninterrrupted scintillations.

  14. Particle tracking with scintillating fibers and position sensitive photomultipliers

    SciTech Connect

    C.F. Perdrisat; R. Pourang; D. Koechner; D. Raine, III; B. Kross; S. Majewski; A. Weisenberger; R. Wojcik; K. Zorn; V. Punjabi; A. Day

    1991-11-01

    The use of position-sensitive phototubes in conjunction with scintillating plastic fibers for a particle tracking application in a future focal plane polarimeter (FPP) in the hadron arm of the hall A HRS 2 facility at the Continuous Electron Beam Accelerator Facility (CEBAF). Current results indicate that the design parameters of the FPP in the hadron arm of the double spectrometer facility HRS2 can be met with a design which couples round or square fibers 3 mm in size to Hamamatsu R4135 phototubes. Position resolutions {sigma}x or {sigma}y on the order of 0.6 mm are obtained in the phototubes. Detector structures with staggered double fiber layers lead to overall resolution of {sigma}=1 mm, and detection efficiencies close to 1. The characteristic speed of these detectors makes them particularly appropriate for the high rates which are expected with the 200-{micro}A continuous wave beam at CEBAF.

  15. Pulse-shape discrimination scintillators for homeland security applications

    NASA Astrophysics Data System (ADS)

    Ellis, Mark E.; Duroe, Kirk; Kendall, Paul A.

    2016-09-01

    An extensive programme of research has been conducted for scintillation liquids and plastics capable of neutron-gamma discrimination for deployment in future passive and active Homeland Security systems to provide protection against radiological and nuclear threats. The more established detection materials such as EJ-301 and EJ-309 are compared with novel materials such as EJ-299-33 and p-terphenyl. This research also explores the benefits that can be gained from improvements in the analogue-to-digital sampling rate and sample bit resolution. Results are presented on the Pulse Shape Discrimination performance of various detector and data acquisition combinations and how optimum configurations from these studies have been developed into field-ready detector arrays. Early results from application-specific experimental configurations of multi-element detector arrays are presented.

  16. Development of a novel scintillation-trigger detector for the MTV experiment using aluminum-metallized film tapes

    NASA Astrophysics Data System (ADS)

    Tanaka, S.; Ozaki, S.; Sakamoto, Y.; Tanuma, R.; Yoshida, T.; Murata, J.

    2014-07-01

    A new type of a trigger-scintillation counter array designed for the MTV experiment at TRIUMF-ISAC has been developed, which uses aluminum-metallized film tape for wrapping to achieve the required assembling precision of ±0.5 mm. The MTV experiment uses a cylindrical drift chamber (CDC) as the main electron-tracking detector. The barrel-type trigger counter is placed inside the CDC to generate a trigger signal using 1 mm thick, 300 mm long thin plastic scintillation counters. Detection efficiency and light attenuation compared with conventional wrapping materials are studied.

  17. Scintillation observations near the sun

    NASA Technical Reports Server (NTRS)

    Coles, W. A.; Rickett, B. J.; Scott, S. L.

    1978-01-01

    Results on the electron density spectrum, the random velocity and the mean velocity of the solar wind in the region from 5 to 100 solar radii are presented. Results are based on intensity scintillations of incoherent radio sources at different locations and different radio frequencies. The shape of the electron density irregularity spectrum is shown to be well modeled by a power law in wavenumber with a slope that abruptly steepens at higher wavenumbers. This two slope power law model is shown to have a break (defined as the wavenumber of the change of slope) that increases with decreasing distance from the Sun. The fractional random velocity is shown to be insignificant at distances of greater than 40 solar radii, but shows a steady increase with decreasing solar distance inside of 40 solar radii.

  18. Further Investigations of the Effect of Replacing Lithium by Sodium on Lithium Silicate Scintillating Glass Efficiency

    SciTech Connect

    Bliss, Mary; Aker, Pamela M.; Windisch, Charles F.

    2012-02-15

    Ce3+ doped lithium (6Li) silicate glasses are thermal neutron detectors. Prior work showed that when sodium (Na) is substituted for Li the scintillation efficiency, under beta particle stimulation, increased and then decreased as the sodium (Na) content was increased [1]. When all the 6Li was replaced by Na no scintillation was observed. Raman spectra, acquired using a visible excitation source provided no evidence of anomalous behavior. SEM microscopy did show some phase separation, but there was no obvious correlation with the scintillation efficiency. We have reexamined these glass samples using deep UV Raman excitation which reduces fluorescence interference. The newly acquired spectra show evidence of phase separation in the glasses. Specifically we see a peak at 800 cm-1 Raman shift which can be assigned to a vitreous silica moiety that results from phase separation. There is a strong correlation between this peak's area, the scintillation efficiency, and the Na content. The observed trend suggests that phase separation enhances scintillation and addition of Na reduces the amount of phase separation. We also see evidence of at least two defect structures that can be tentatively assigned to a three-membered ring structure and an oxygen vacancy. The latter is fairly strongly correlated with enhanced scintillation efficiency.

  19. Medical imaging scintillators from glass-ceramics using mixed rare-earth halides

    NASA Astrophysics Data System (ADS)

    Beckert, M. Brooke; Gallego, Sabrina; Ding, Yong; Elder, Eric; Nadler, Jason H.

    2016-10-01

    Recent years have seen greater interest in developing new luminescent materials to replace scintillator panels currently used in medical X-ray imaging systems. The primary areas targeted for improvement are cost and image resolution. Cost reduction is somewhat straightforward in that less expensive raw materials and processing methods will yield a less expensive product. The path to improving image resolution is more complex because it depends on several properties of the scintillator material including density, transparency, and composition, among others. The present study focused on improving image resolution using composite materials, known as glass-ceramics that contain nanoscale scintillating crystallites formed within a transparent host glass matrix. The small size of the particles and in-situ precipitation from the host glass are key to maintaining transparency of the composite scintillator, which ensures that a majority of the light produced from absorbed X-rays can actually be used to create an image of the patient. Because light output is the dominating property that determines the image resolution achievable with a given scintillator, it was used as the primary metric to evaluate performance of the glass-ceramics relative to current scintillators. Several glass compositions were formulated and then heat treated in a step known as "ceramization" to grow the scintillating nanocrystals, whose light output was measured in response to a 65 kV X-ray source. Performance was found to depend heavily on the thermal history of the glass and glass-ceramic, and so additional studies are required to more precisely determine optimal process temperatures. Of the compositions investigated, an alumino-borosilicate host glass containing 56mol% scintillating rare-earth halides (BaF2, GdF3, GdBr3, TbF3) produced the highest recorded light output at nearly 80% of the value recorded using a commercially-available GOS:Tb panel as a reference.

  20. New Organic Scintillators for Neutron Detection

    SciTech Connect

    Iwanowska, Joanna; Szczeniak, Tomasz

    2010-01-05

    This paper present the current work on neutron detection in Soltan Institute for Nuclear Studies. Lately, we have focused our research on the development of new organic scintillators including liquid scintillators for neutron detection and associated measurements. We measured liquid scintillators (also {sup 10}B-doped for thermal neutron detection){sup 3}He tubes, composites, etc. Response of the following detectors on thermal neutrons, fast neutrons and gamma radiation - the pulse shape discrimination (PSD)- has been mainly performed by means of a zero-crossing (ZC) method.

  1. Photodiode scintillation detector for radiac instrumentation

    NASA Astrophysics Data System (ADS)

    Nirschl, Joseph C.

    1984-10-01

    Scintillation detectors have traditionally employed photomultiplier tubes (PMTs), with the attendant drawback of relatively high cost and need for a high voltage supply. This article reviews evaluation of a photodiode type scintillation detector, which exhibits promising features (small size and low power) for radiation survey meter application. Gamma radiation response characteristics, both for pulse and dc-mode of detector operation are presented, along with an example of a simple, high-range digital radiacmeter (breadboard design), utilizing this photodiode scintillation detector in conjunction with a single-chip A/D converter/LCD display driver and featuring low power demand (15 mW).

  2. Large volume flow-through scintillating detector

    DOEpatents

    Gritzo, Russ E.; Fowler, Malcolm M.

    1995-01-01

    A large volume flow through radiation detector for use in large air flow situations such as incinerator stacks or building air systems comprises a plurality of flat plates made of a scintillating material arranged parallel to the air flow. Each scintillating plate has a light guide attached which transfers light generated inside the scintillating plate to an associated photomultiplier tube. The output of the photomultiplier tubes are connected to electronics which can record any radiation and provide an alarm if appropriate for the application.

  3. Measurement of light emission in scintillation vials

    SciTech Connect

    Duran Ramiro, M. Teresa; Garcia-Torano, Eduardo

    2005-09-15

    The efficiency and energy resolution of liquid scintillation counting (LSC) systems are strongly dependent on the optical characteristics of scintillators, vials, and reflectors. This article presents the results of measurements of the light-emission profile of scintillation vials. Two measurement techniques, autoradiographs and direct measurements with a photomultiplier tube, have been used to obtain light-emission distribution for standard vials of glass, etched glass and polyethylene. Results obtained with both techniques are in good agreement. For the first time, the effect of the meniscus in terms of light contribution has been numerically estimated. These results can help design LSC systems that are more efficient in terms of light collection.

  4. Cosmetic Plastic Surgery Statistics

    MedlinePlus

    2014 Cosmetic Plastic Surgery Statistics Cosmetic Procedure Trends 2014 Plastic Surgery Statistics Report Please credit the AMERICAN SOCIETY OF PLASTIC SURGEONS when citing statistical data or using ...

  5. Plastics Technician.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document contains 16 units to consider for use in a tech prep competency profile for the occupation of plastics technician. All the units listed will not necessarily apply to every situation or tech prep consortium, nor will all the competencies within each unit be appropriate. Several units appear within each specific occupation and would…

  6. New observations of scintillation climatology from the Scintillation Network Decision Aid (SCINDA)

    NASA Astrophysics Data System (ADS)

    Su, Y.; Caton, R. G.; Wiens, K.; Groves, K. M.

    2012-12-01

    The Scintillation Network Decision Aid (SCINDA) was established with three ground sites in the mid-1990's by the Air Force Research Laboratory and has continued to grow into a global scintillation observation network. This system consists of an array of VHF and GPS receivers which continually measure scintillation in the equatorial region. In the past few years, the extended network of ground stations has expanded into the African sector. Initial results from yearly scintillation data obtained from two VHF receivers in Narobi, Kenya and Bahir Dar, Ethiopia in 2011 indicate the presence of scintillation activity throughout the June-July -August (northern summer) season which is inconsistent with current state-of-the-art ionospheric climatology models. It is well known that seasonal equatorial scintillation patterns vary with longitude based on geographical location. For example, the scintillation activity at VHF frequencies are absent in the Pacific sector during the months of November to February while observations from South America show nearly continuous scintillation during this same time period. With little to no ground-based observations, the scintillation climatology over the African region has not been well understood. In the paper, we will present S4 measurements various longitudinal sectors, including the first look at solar maximum type conditions over the African sector, and provide comparisons with output from a global climatology model.

  7. Severe and localized GNSS scintillation at the poleward edge of the nightside auroral oval during intense substorm aurora

    NASA Astrophysics Data System (ADS)

    Meeren, Christer; Oksavik, Kjellmar; Lorentzen, Dag A.; Rietveld, Michael T.; Clausen, Lasse B. N.

    2015-12-01

    In this paper we study how GPS, GLONASS, and Galileo navigation signals are compromised by strong irregularities causing severe phase scintillation (σϕ>1) in the nightside high-latitude ionosphere during a substorm on 3 November 2013. Substorm onset and a later intensification coincided with polar cap patches entering the auroral oval to become auroral blobs. Using Global Navigation Satellite Systems (GNSS) receivers and optical data, we show severe scintillation driven by intense auroral emissions in the line of sight between the receiver and the satellites. During substorm expansion, the area of scintillation followed the intense poleward edge of the auroral oval. The intense auroral emissions were colocated with polar cap patches (blobs). The patches did not contain strong irregularities, neither before entering the auroral oval nor after the aurora had faded. Signals from all three GNSS constellations were similarly affected by the irregularities. Furthermore, two receivers spaced around 120km apart reported highly different scintillation impacts, with strong scintillation on half of the satellites in one receiver and no scintillation in the other. This shows that areas of severe irregularities in the nightside ionosphere can be highly localized. Amplitude scintillations were low throughout the entire interval.

  8. Scintillations of partially coherent Laguerre Gaussian beams

    NASA Astrophysics Data System (ADS)

    Yüceer, M.; Eyyuboğlu, H. T.; Lukin, I. P.

    2010-12-01

    Scintillations of Laguerre-Gaussian (LG) beams for weak atmospheric turbulence conditions are derived for on-axis receiver positions by using Huygens-Fresnel (HF) method in semi-analytic fashion. Numerical evaluations indicate that at the fully coherent limit, higher values of radial mode numbers will give rise to more scintillations, at medium and low partial coherence levels, particularly at longer propagation distances, scintillations will fall against rises in radial mode numbers. At small source sizes, the scintillations of LG beams having full coherence will initially rise, reaching saturation at large source sizes. For LG beams with low partial coherence levels, a steady fall toward the larger source sizes is observed. Partially coherent beams of medium levels generally exhibit a rising trend toward the large source sizes, also changing the respective positions of the related curves. Beams of low coherence levels will be less affected by the variations in the refractive index structure constant.

  9. Efficiency and timing resolution of scintillator tiles read out with silicon photomultipliers

    NASA Astrophysics Data System (ADS)

    Pooth, O.; Weingarten, S.; Weinstock, L.

    2016-01-01

    Silicon photomultipliers (SiPM) are semiconductor photo sensors that have the potential to replace photomultiplier tubes (PMT) in various fields of application. We present detectors consisting of 30 × 30 × 0.5 cm3 fast plastic scintillator tiles read out with SiPMs. The detectors offer great electronic and mechanical advantages over the classical PMT-scintillator combination. SiPMs are very compact devices that run independent of magnetic fields at low voltages and no light guides between the scintillator and the SiPM are necessary in the presented layouts. Three prototypes, two of which with integrated wavelength shifting fibres, have been tested in a proton beam at the COSY accelerator at Forschungszentrum Jülich. The different layouts are compared in terms of most probable pulse height, detection efficiency and noise behaviour as well as timing resolution. The spatial distributions of these properties across the scintillator surface are presented. The best layout can be operated at a mean efficiency of bar epsilon=99.9 % while sustaining low noise rates in the order of 10 Hz with a timing resolution of less than 3 ns. Both efficiency and timing resolution show good spatial homogeneity.

  10. Response of a lithium gadolinium borate scintillator in monoenergetic neutron fields.

    PubMed

    Williams, A M; Beeley, P A; Spyrou, N M

    2004-01-01

    Accurate estimation of neutron dose requires knowledge of the neutron energy distribution in the working environment. Existing neutron spectrometry systems, Bonner spheres for example, are large and bulky, and require long data acquisition times. A portable system that could indicate the approximate neutron energy spectrum in a short time would be extremely useful in radiation protection. A composite scintillator, consisting of lithium gadolinium borate crystals in a plastic scintillator matrix, produced by Photogenics is being tested for this purpose. A prototype device based on this scintillator and digital pulse processing electronics has been calibrated using quasi-monoenergetic neutron fields at the low-scatter facility of the UK National Physical Laboratory (NPL). Energies selected were 144, 250, 565, 1400, 2500 and 5000 keV, with correction for scattered neutrons being made using the shadow cone technique. Measurements were also made in the NPL thermal neutron field. Pulse distributions collected with the digitiser in capture-gated mode are presented, and detection efficiency and energy resolution derived. For comparison, neutron spectra were also collected using the commercially available Microspec N-Probe from Bubble Technology Industries, which consists of an NE213 scintillator and a 3He proportional counter.

  11. Ternary liquid scintillator for optical fiber applications

    DOEpatents

    Franks, Larry A.; Lutz, Stephen S.

    1982-01-01

    A multicomponent liquid scintillator solution for use as a radiation-to-light converter in conjunction with a fiber optic transmission system. The scintillator includes a quantity of 5-amino-9-diethylaminobenz (a) phenoxazonium nitrate (Nile Blue Nitrate) as a solute in a fluor solvent such as benzyl alcohol. The use of PPD as an additional solute is also disclosed. The system is controllable by addition of a suitable quenching agent, such as phenol.

  12. Liquid scintillators for optical fiber applications

    DOEpatents

    Franks, Larry A.; Lutz, Stephen S.

    1982-01-01

    A multicomponent liquid scintillator solution for use as a radiation-to-light converter in conjunction with a fiber optic transmission system. The scintillator includes a quantity of 1, 2, 4, 5, 3H, 6H, 1 OH, tetrahydro-8-trifluoromethyl (1) benzopyrano (9, 9a, 1-gh) quinolizin-10-one (Coumarin) as a solute in a fluor solvent such as benzyl alcohol or pseudo-cumene. The use of BIBUQ as an additional or primary solute is also disclosed.

  13. Multi-GNSS for Ionospheric Scintillation Studies

    NASA Astrophysics Data System (ADS)

    Morton, Y.

    2015-12-01

    GNSS have been widely used for ionospheric monitoring. We anticipate over 160 GNSS satellites broadcasting 400 signals by 2023, nearly double the number today. With their well-defined signal structures, high spatial density and spectral diversity, GNSS offers low cost and distributed passive sensing of ionosphere effects. There are, however, many challenges to utilize GNSS resources to characterize and forecast ionospheric scintillation. Originally intended for navigation purposes, GNSS receivers are designed to filter out nuisance effects due to ionosphere effects. GNSS measurements are plagued with errors from multipath, oscillator jitters, processing artifacts, and neutral atmosphere effects. Strong scintillation events are often characterized by turbulent structures in ionosphere, causing simultaneous deep amplitude fading and abrupt carrier phase changes. The combined weak signal and high carrier dynamics imposes conflicting requirements for GNSS receiver design. Therefore, GNSS receivers often experience cycle slips and loss of lock of signals during strong scintillation events. High quality, raw GNSS signals bearing space weather signatures and robust receiver algorithms designed to capture these signatures are needed in order for GNSS to be a reliable and useful agent for scintillation monitoring and forecasting. Our event-driven, reconfigurable data collection system is designed to achieve this purpose. To date, our global network has collected ~150TB of raw GNSS data during space weather events. A suite of novel receiver processing algorithms has been developed by exploitating GNSS spatial, frequency, temporal, and constellation diversity to process signals experiencing challenging scintillation impact. The algorithms and data have advanced our understanding of scintillation impact on GNSS, lead to more robust receiver technologies, and enabled high spatial and temporal resolution depiction of ionosphere responses to solar and geomagnetic conditions. This

  14. GNSS station characterisation for ionospheric scintillation applications

    NASA Astrophysics Data System (ADS)

    Romano, Vincenzo; Spogli, Luca; Aquino, Marcio; Dodson, Alan; Hancock, Craig; Forte, Biagio

    2013-10-01

    Ionospheric scintillations are fluctuations in the phase and amplitude of the signals from GNSS (Global Navigation Satellite Systems) occurring when they cross regions of electron density irregularities in the ionosphere. Such disturbances can cause serious degradation of several aspects of GNSS system performance, including integrity, accuracy and availability. The two indices adopted worldwide to characterise ionospheric scintillations are: the amplitude scintillation index, S4, which is the standard deviation of the received power normalised by its mean value, and the phase scintillation index, σΦ, which is the standard deviation of the de-trended carrier phase. Collaborative work between NGI and INGV supports a permanent network of GISTM (GPS Ionospheric Scintillation and TEC Monitor) receivers that covers a wide range of latitudes in the northern European sector. Data from this network has contributed significantly to several papers during the past few years (see e.g. De Franceschi et al., 2008; Aquino et al., 2009; Spogli et al., 2009, 2010; Alfonsi et al., 2011). In these investigations multipath effects and noise that contaminate the scintillation measurements are largely filtered by applying an elevation angle threshold. A deeper analysis of the data quality and the development of a more complex filtering technique can improve the results obtained so far. The structures in the environment of each receiver in the network which contaminate scintillation measurements should be identified in order to improve the quality of the scintillation and TEC data by removing error sources due to the local environment. The analysis in this paper considers a data set characterised by quiet ionospheric conditions of the mid-latitude station located in Nottingham (UK), followed by a case study of the severe geomagnetic storm, which occurred in late 2003, known generally as the "Halloween Storm".

  15. Crystal growth and scintillation properties of strontium iodide scintillators

    SciTech Connect

    van Loef, Edgar; Wilson, Cody; Cherepy, Nerine; Payne, Steven; Choong, Woon-Seng; Moses, William W.; Shah, Kanai

    2009-06-01

    Single crystals of SrI{sub 2}:Eu and SrI{sub 2}:Ce/Na were grown from anhydrous iodides by the vertical Bridgman technique in evacuated silica ampoules. Growth rates were of the order of 5-30 mm/day. Radioluminescence spectra of SrI{sub 2}:Eu and SrI{sub 2}:Ce/Na exhibit a broad band due to Eu{sup 2+} and Ce{sup 3+} emission, respectively. The maximum in the luminescence spectrum of SrI{sub 2}:Eu is found at 435 nm. The spectrum of SrI{sub 2}:Ce/Na exhibits a doublet peaking at 404 and 435 nm attributed to Ce{sup 3+} emission, while additional impurity - or defected - related emission is present at approximately 525 nm. The strontium iodide scintillators show very high light yields of up to 120,000 photons/MeV, have energy resolutions down to 3% at 662 keV (Full Width Half Maximum) and exhibit excellent light yield proportionality with a standard deviation of less than 5% between 6 and 460 keV.

  16. Scintillation Hole Observed by FORMOSAT-3/COSMIC

    NASA Astrophysics Data System (ADS)

    Chen, Shih Ping; Yenq Liu, Jann; Krishnanunni Rajesh, Panthalingal

    2013-04-01

    Ionospheric scintillations can significantly disturb satellite positioning, navigation, and communication. FORMOSAT-3/COSMIC provides the first 3-D global observation by solo instrument (radio occultation experiment, GOX). The GPS L-band amplitude fluctuation from 50Hz signal is received and recorded by F3/C GOX to calculate S4-index from 50-800km altitude. The global F3/C S4 index are subdivided and examined in various latitudes, longitudes, altitudes, and seasons during 2007-2012. The F-region scintillations in the equatorial and low-latitude ionosphere start around post-sunset period and often persist till post-midnight hours (0300 MLT, magnetic local time) during the March and September equinox as well as December Solstice seasons. The E-region scintillations reveal a clear solar zenith effect and yield pronounced intensities in mid-latitudes during the Summer Solstice seasons, which are well correlated with occurrences of the sporadic E-layer. It is interesting to find there is no scintillation, which is termed "scintillation hole", in the E region ranging from 80 to 130km altitude over the South Africa region, and become the most pronounced in November-January (December Solstice seasons or summer months). Other space-borne and ground based observations are use to confirm the existence of the scintillation hole.

  17. Ionospheric scintillation effects on single frequency GPS

    NASA Astrophysics Data System (ADS)

    Steenburgh, R. A.; Smithtro, C. G.; Groves, K. M.

    2008-04-01

    Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active within, although not limited to, a belt encircling the Earth within 20 degrees of the geomagnetic equator. As GPS applications and users increase, so does the potential for degraded precision and availability from scintillation. We examined amplitude scintillation data spanning 7 years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/American longitudinal sector as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K. in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at 1 min resolution. We examine diurnal, seasonal, and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

  18. Design considerations for a scintillating plate calorimeter

    NASA Astrophysics Data System (ADS)

    Job, P. K.; Price, L. E.; Proudfoot, J.; Handler, T.; Gabriel, T. A.

    1992-06-01

    Results of the simulation studies for the design of a scintillating plate calorimeter for an SSC detector are presented. These simulation studies have been carried out with the CALOR89 code. The results show that both lead and uranium can yield good compensation in practical sampling geometries. However, the significant delayed energy release in the uranium systems can lead to a serious pile up problem at high rates. In the energy range under consideration, an iron-scintillator system is not compensating at any absorber to scintillator ratio. An inhomogeneous calorimeter with 4γ of lead-scintillator in a compensating configuration followed by 4γ of iron-scintillator with moderate sampling is found to perform as well as a homogeneous lead-scintillator compensating calorimeter. In such inhomogeneous systems the hadronic signal from different segments are weighted by a scheme based on minimum ionizing d E/d X. We show that, in a properly optimised three segment, compensation and good hadronic resolution can be achieved by appropriately weighting the signal from the segments.

  19. The detection of minimum ionizing particles with scintillating fibers using multi-pixel hybrid photodiodes

    SciTech Connect

    Datema, C.P.; Meng, L.J.; Ramsden, D.

    1998-06-01

    Recent measurements of the performance of the newly available multi-pixel Hybrid Photodiode (M-HPD) have demonstrated their particular value in the detection of very low light-level signals in the visible region. The single and multiple photo-electron response characteristics of these devices is unmatched by any other room-temperature device. This characteristic, coupled with their speed of response and the availability of an internally-generated trigger signal when one or more of the pixels detect an event, makes them particularly interesting as possible photo-detectors for fast plastic scintillators and, in particular, as detectors for reading out scintillating fibers. The results of tests made when Minimum Ionizing Particles (MIPs) pass through single and multi-clad plastic scintillating fibers have confirmed the usefulness of these devices in particle-tracking applications. The technique used to read-out 61 channels of data is described along with a way to view as many as 2,000 fibers with just two 61-pixel M-HPDs.

  20. [Effects of whole field-surface plastic mulching and planting in furrow on soil temperature, soil moisture, and corn yield in arid area of Gansu Province, Northwest China].

    PubMed

    Wang, Hong-li; Zhang, Xu-cheng; Song, Shang-you; Ma, Yi-Fan; Yu, Xian-feng; Liu, Yan-lan

    2011-10-01

    Taking spring corn (Zea mays) cultivar Shendan 16 as test material, a field experiment was conducted to study the effects of the treatments whole-field surface plastic mulching and planting in furrow (PMF), whole-field surface sand mulching and flat planting (SM), and uncovered and flat planting (CK) on the soil temperature, soil moisture, and corn yield on the dry land of arid area (annual average precipitation 415 mm) in middle Gansu Province. Comparing with CK, treatments PMF and SM increased the average temperature in 0-25 cm soil layer before tasselling stage, with the highest increment in treatment PMF. As for the soil water consumption, its depth in the three treatments increased with increasing years of planting. In the first year of planting, the soil water consumption was the most in 20-120 cm soil layer; whereas in the second year, the consumption was the most in 120-200 cm soil layer, with the soil water loss being the highest in treatment PMF. Treatment PMF had the highest grain number, grain weight per spike, and 100-grain weight, followed by treatment SM, and CK. In 2009 and 2010, the average grain number, average grain weight per spike, and average 100-grain weight in treatment PMF were increased by 13.5% and 114.2%, 29.8% and 321.1%, and 14.4% and 95.4% respectively, as compared to treatments SM and CK, and the grain yield and water use efficiency in treatments PMF and SM were increased by 333.1% and 240.2%, and 290.6% and 227.6%, respectively, as compared to CK. After two years continuous cropping of corn, the soil water loss in 120-200 cm soil layer in treatment PMF was up to 72 mm, being significantly higher than that in treatments SM (45 mm) and CK (40 mm). It was suggested that PMF could increase the soil temperature at seedling-tasselling stage, promote the corn growth in its early growth period, improve the soil water use by corn, and consequently, increase the grain number per spike and 100-grain weight, manifesting a good effect in

  1. Plastic bronchitis.

    PubMed

    Singhi, Anil Kumar; Vinoth, Bharathi; Kuruvilla, Sarah; Sivakumar, Kothandam

    2015-01-01

    Plastic bronchitis, a rare but serious clinical condition, commonly seen after Fontan surgeries in children, may be a manifestation of suboptimal adaptation to the cavopulmonary circulation with unfavorable hemodynamics. They are ominous with poor prognosis. Sometimes, infection or airway reactivity may provoke cast bronchitis as a two-step insult on a vulnerable vascular bed. In such instances, aggressive management leads to longer survival. This report of cast bronchitis discusses its current understanding. PMID:26556975

  2. Emergent Spatial Patterns of Excitatory and Inhibitory Synaptic Strengths Drive Somatotopic Representational Discontinuities and their Plasticity in a Computational Model of Primary Sensory Cortical Area 3b.

    PubMed

    Grajski, Kamil A

    2016-01-01

    Mechanisms underlying the emergence and plasticity of representational discontinuities in the mammalian primary somatosensory cortical representation of the hand are investigated in a computational model. The model consists of an input lattice organized as a three-digit hand forward-connected to a lattice of cortical columns each of which contains a paired excitatory and inhibitory cell. Excitatory and inhibitory synaptic plasticity of feedforward and lateral connection weights is implemented as a simple covariance rule and competitive normalization. Receptive field properties are computed independently for excitatory and inhibitory cells and compared within and across columns. Within digit representational zones intracolumnar excitatory and inhibitory receptive field extents are concentric, single-digit, small, and unimodal. Exclusively in representational boundary-adjacent zones, intracolumnar excitatory and inhibitory receptive field properties diverge: excitatory cell receptive fields are single-digit, small, and unimodal; and the paired inhibitory cell receptive fields are bimodal, double-digit, and large. In simulated syndactyly (webbed fingers), boundary-adjacent intracolumnar receptive field properties reorganize to within-representation type; divergent properties are reacquired following syndactyly release. This study generates testable hypotheses for assessment of cortical laminar-dependent receptive field properties and plasticity within and between cortical representational zones. For computational studies, present results suggest that concurrent excitatory and inhibitory plasticity may underlie novel emergent properties. PMID:27504086

  3. Emergent Spatial Patterns of Excitatory and Inhibitory Synaptic Strengths Drive Somatotopic Representational Discontinuities and their Plasticity in a Computational Model of Primary Sensory Cortical Area 3b

    PubMed Central

    Grajski, Kamil A.

    2016-01-01

    Mechanisms underlying the emergence and plasticity of representational discontinuities in the mammalian primary somatosensory cortical representation of the hand are investigated in a computational model. The model consists of an input lattice organized as a three-digit hand forward-connected to a lattice of cortical columns each of which contains a paired excitatory and inhibitory cell. Excitatory and inhibitory synaptic plasticity of feedforward and lateral connection weights is implemented as a simple covariance rule and competitive normalization. Receptive field properties are computed independently for excitatory and inhibitory cells and compared within and across columns. Within digit representational zones intracolumnar excitatory and inhibitory receptive field extents are concentric, single-digit, small, and unimodal. Exclusively in representational boundary-adjacent zones, intracolumnar excitatory and inhibitory receptive field properties diverge: excitatory cell receptive fields are single-digit, small, and unimodal; and the paired inhibitory cell receptive fields are bimodal, double-digit, and large. In simulated syndactyly (webbed fingers), boundary-adjacent intracolumnar receptive field properties reorganize to within-representation type; divergent properties are reacquired following syndactyly release. This study generates testable hypotheses for assessment of cortical laminar-dependent receptive field properties and plasticity within and between cortical representational zones. For computational studies, present results suggest that concurrent excitatory and inhibitory plasticity may underlie novel emergent properties. PMID:27504086

  4. Plastics recycling: challenges and opportunities

    PubMed Central

    Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

    2009-01-01

    Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3–4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it

  5. Plastics recycling: challenges and opportunities.

    PubMed

    Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

    2009-07-27

    Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3-4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it

  6. Plastics recycling: challenges and opportunities.

    PubMed

    Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

    2009-07-27

    Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3-4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it

  7. High-energy X-ray detection by hafnium-doped organic-inorganic hybrid scintillators prepared by sol-gel method

    SciTech Connect

    Sun, Yan; Koshimizu, Masanori Yahaba, Natsuna; Asai, Keisuke; Nishikido, Fumihiko; Kishimoto, Shunji; Haruki, Rie

    2014-04-28

    With the aim of enhancing the efficiency with which plastic scintillators detect high-energy X-rays, hafnium-doped organic-inorganic hybrid scintillators were fabricated via a sol-gel method. Transmission electron microscopy of sampled material reveals the presence of Hf{sub x}Si{sub 1−x}O{sub 2} nanoparticles, dispersed in a polymer matrix that constitutes the active material of the X-ray detector. With Hf{sub x}Si{sub 1−x}O{sub 2} nanoparticles incorporated in the polymer matrix, the absorption edge and the luminescence wavelength is shifted, which we attribute to Mie scattering. The detection efficiency for 67.4-keV X-rays in a 0.6-mm-thick piece of this material is two times better than the same thickness of a commercial plastic scintillator-NE142.

  8. The feasibility of using boron-loaded plastic fibers for neutron detection

    SciTech Connect

    Grazioso, R.F.; Heger, A.S.; Ensslin, N.; Mayo, D.R.; Mercer, D.J.; Miller, M.C.; Russo, P.A.

    1998-12-01

    The results from simulations and laboratory experiments with boron-loaded plastic scintillating fibers as a nondestructive assay tool are presented. Single and multiclad fibers in three diameters of 0.25, 0.5, and 1 mm were examined for their application in neutron coincident counting. For this application, the simulation results show that various configurations of boro-loaded plastic scintillating fibers have a die-away time ({tau}) of 12 {micro}s with an efficiency ({var_epsilon}) of 50%. For a comparable efficiency, {sup 3}He proportional tubes have a typical die-away time of 50 {micro}s. The shortened die-away time can reduce the relative error for measurement of similar samples by up to 50%. Plastic scintillating fibers also offer flexible configurations with the potential to discriminate between signals from gamma-ray and neutron events. To date, the emphasis of the investigation has been the detection capability of plastic scintillating fibers for neutrons and gamma rays and evaluation of their ability to discriminate between the two events. Quantitative calculations and experiments have also been conducted to determine the light output, evaluate the noise,quantify light attenuation, and determine neutron detection efficiency. Current experimental data support the analytical results that boron-loaded plastic fibers can detect thermal neutrons with performance metrics that are comparable or better than those of {sup 3}He proportional tubes.

  9. Shielding Effects of a Building Structure on the Energy Deposit of Cosmic Rays in a Simple Wavelength Shifter-Based Scintillator

    ERIC Educational Resources Information Center

    Aiola, Salvatore; La Rocca, Paola; Riggi, Francesco; Riggi, Simone

    2012-01-01

    An experimental setup, based on a plastic scintillator with an embedded wavelength shifter fibre and photosensors at the two ends, has been used to detect cosmic muons in undergraduate laboratory activities. Time and amplitude information from the two photosensors were measured using the time-over-threshold technique. The distribution of the…

  10. Real-time monitoring and diagnosis of scintillation dosimeters using an ultraviolet light emitting diode

    NASA Astrophysics Data System (ADS)

    Yin, Y.; Lambert, J.; McKenzie, D. R.; Suchowerska, N.

    2008-05-01

    Plastic scintillator fibre optic dosimeters (FODs) have advantages for both brachytherapy and external beam radiotherapy applications. Convenient real-time monitoring and diagnosis of such dosimeters are desirable because of changes in the optical circuit that may arise in use. In this paper, we propose and demonstrate a real-time method using ultraviolet light emitting diodes (LED) to stimulate the scintillator and to diagnose failures of FODs. Key aspects of the LED FOD dosimetry design are investigated, enabling the design of a stable and accurate real-time monitoring dosimetry system. We demonstrate experimentally that the real-time monitoring FOD system is convenient to be used to monitor FOD dosimeters and to diagnose their failures resulted from different mechanisms.

  11. Ionosphere scintillations associated with features of equatorial ionosphere

    NASA Technical Reports Server (NTRS)

    Chandra, H.; Vats, H. O.; Sethia, G.; Deshpande, M. R.; Rastogi, R. G.; Sastri, J. H.; Murthy, B. S.

    1979-01-01

    Amplitude scintillations of radio beacons aboard the ATS-6 satellite on 40 MHz, 140 MHz and 360 MHz recorded during the ATS-6 phase II at an equatorial station Ootacamund (dip 4 deg N) and the ionograms at a nearby station Kodaikanal (dip 3.5 deg N) are examined for scintillation activity. Only sporadic E events, other than Es-q, Es-c or normal E are found to be associated with intense daytime scintillations. Scintillations are also observed during night Es conditions. The amplitude spread is associated with strong scintillations on all frequencies while frequency spread causes weaker scintillations and that mainly at 40 MHz.

  12. Automated and angular time-synchronized directional gamma-ray scintillation sensor

    SciTech Connect

    Kronenberg, S.; Brucker, G.J.

    1998-12-31

    The authors` previous research resulted in directional sensors for gamma rays and X rays that have a 4{pi} solid angle of acceptance and, at the same time, a high angular resolution that is limited only by their ability to measure small angles. Angular resolution of {approximately}1 s of arc was achieved. These sensors are capable of operating and accurately detecting high and very low intensity radiation patterns. Such a system can also be used to image broad area sources and their scattering patterns. The principle of operation and design of directional sensors used in this study was described elsewhere; however, for convenience, a part of that text is repeated here. It was shown analytically that the angular distribution of radiation incident on the sensor is proportional to the first derivative of the scan data, that is, of the events` count rate versus orientation of the detector. The previously published results were obtained with a annual operating system. The detector assembly was set at a specific angle, and a pulse rate count was made. This was repeated at numerous other angles of orientation, a time-consuming and labor-intensive process. Recently, the authors automated this system, which is based on the detection of scintillations. The detector, which consists of a stack of plates of Lucite, plastic scintillator, and lead foils, rotates by means of a motor in front of a stationary photomultiplier tube (PMT). One revolution per second was chosen for the motor. At time zero, a trigger indicates that a revolution has started. The angle of orientation of the detector in the laboratory system is proportional to the time during one revolution. The process repeats itself a desired number of times. The trigger signal initiates a scan of a multichannel scalar (MCS). The detector assembly is allowed to rotate in the radiation field, and the MCS scans are repeated in an accumulated mode of operation until enough events are collected for the location of the

  13. Large area position sensitive β-detector

    NASA Astrophysics Data System (ADS)

    Vaintraub, S.; Hass, M.; Edri, H.; Morali, N.; Segal, T.

    2015-03-01

    A new conceptual design of a large area electron detector, which is position and energy sensitive, was developed. This detector is designed for beta decay energies up to 4 MeV, but in principle can be re-designed for higher energies. The detector incorporates one large plastic scintillator and, in general, a limited number of photomultipliers (7 presently). The current setup was designed and constructed after an extensive Geant4 simulation study. By comparison of a single hit light distribution between the various photomultipliers to a pre-measured accurate position-response map, the anticipated position resolution is around 5 mm. The first benchmark experiments have been conducted in order to calibrate and confirm the position resolution of the detector. The new method, results of the first test experiments and comparison to simulations are presented.

  14. Interplanetary scintillation observations with the Cocoa Cross radio telescope

    NASA Technical Reports Server (NTRS)

    Cronyn, W. M.; Shawhan, S. D.; Erskine, F. T.; Huneke, A. H.; Mitchell, D. G.

    1976-01-01

    Physical and electrical parameters for the 34.3-MHz Cocoa Cross radio telescope are given. The telescope is dedicated to the determination of solar-wind characteristics in and out of the ecliptic plane through measurement of electron-density irregularity structure as determined from IPS (interplanetary scintillation) of natural radio sources. The collecting area (72,000 sq m), angular resolution (0.4 deg EW by 0.6 deg NS), and spatial extent (1.3 km EW by 0.8 km NS) make the telescope well suited for measurements of IPS index and frequency scale for hundreds of weak radio sources without serious confusion effects.

  15. One Hundred and One Cases of Plastic Bag Suffocation in the Milan Area Between 1993 and 2013-Correlations, Circumstances, Pathological and Forensic Evidences and Literature Review.

    PubMed

    Crudele, Graziano Domenico Luigi; Di Candia, Domenico; Gentile, Guendalina; Marchesi, Matteo; Rancati, Alessandra; Zoja, Riccardo

    2016-03-01

    Plastic Bag Suffocation is a rare cause of death in developed countries and almost unknown in the rest of the world. This study aims to retrospectively evaluate cases of PBS _asphyxia in Milan's Department of Legal Medicine from 1993 to 2013. Cases were selected from the database of 21,472 autopsies performed in the considered timeframe. One hundred and one cases were considered to be cases of Plastic Bag Suffocation, comprised of 100 suicides, no accidental events and 1 homicide. The most relevant elements pertaining to this type of death were evaluated for both the corpses and the crime scenes. From this study the typical PBS victim is an adult male, aged 52.3 years on average, depressed or afflicted by chronic or terminal diseases, and found at home. In 42.6% of cases, the victims were found with the plastic bag still positioned over their head, fastened by tying. Also common among these cases are drugs, alcohol and chemical abuses. According to the collected data, it is impossible to outline a pathognomonic detrimental background that leads to this cause of death. Crime scene investigation is, therefore, the one and only technical resource for evaluating these cases. PMID:27404609

  16. Compensatory plasticity: time matters.

    PubMed

    Lazzouni, Latifa; Lepore, Franco

    2014-01-01

    Plasticity in the human and animal brain is the rule, the base for development, and the way to deal effectively with the environment for making the most efficient use of all the senses. When the brain is deprived of one sensory modality, plasticity becomes compensatory: the exception that invalidates the general loss hypothesis giving the opportunity of effective change. Sensory deprivation comes with massive alterations in brain structure and function, behavioral outcomes, and neural interactions. Blind individuals do as good as the sighted and even more, show superior abilities in auditory, tactile and olfactory processing. This behavioral enhancement is accompanied with changes in occipital cortex function, where visual areas at different levels become responsive to non-visual information. The intact senses are in general used more efficiently in the blind but are also used more exclusively. New findings are disentangling these two aspects of compensatory plasticity. What is due to visual deprivation and what is dependent on the extended use of spared modalities? The latter seems to contribute highly to compensatory changes in the congenitally blind. Short-term deprivation through the use of blindfolds shows that cortical excitability of the visual cortex is likely to show rapid modulatory changes after few minutes of light deprivation and therefore changes are possible in adulthood. However, reorganization remains more pronounced in the congenitally blind. Cortico-cortical pathways between visual areas and the areas of preserved sensory modalities are inhibited in the presence of vision, but are unmasked after loss of vision or blindfolding as a mechanism likely to drive cross-modal information to the deafferented visual cortex. The development of specialized higher order visual pathways independently from early sensory experience is likely to preserve their function and switch to the intact modalities. Plasticity in the blind is also accompanied with

  17. Radar detection during scintillation. Technical report

    SciTech Connect

    Knepp, D.L.; Reinking, J.T.

    1990-04-01

    Electromagnetic signals that propagate through a disturbed region of the ionosphere can experience scattering which can cause fluctuations in the received amplitude, phase, and angle-of-arrival. This report considers the performance of a radar that must operate through a disturbed propagation environment such as might occur during strong equatorial scintillation, during a barium release experiment or after a high altitude nuclear detonation. The severity of the channel disturbance is taken to range from weak scattering where the signal quadrature components are uncorrelated Gaussian variates. The detection performance of noncoherent combining is compared to that of double threshold (M out of N) combining under various levels of scintillation disturbance. Results are given for detection sensitivity as a function of the scintillation index and the ratio of the radar hopping bandwidth to the channel bandwidth. It is shown that both types of combining can provide mitigation of fading, and that noncoherent combining generally enjoys an advantage in detection sensitivity of about 2 dB. This work serves as a quantitative guideline to the advantages and disadvantages of certain types of detection strategies during scintillation and is, therefore, useful in the radar design process. However, a detailed simulation of the radar detection algorithms is necessary to evaluate a radar design strategy to predict performance under scintillation conditions.

  18. Thallium bromide photodetectors for scintillation detection

    NASA Astrophysics Data System (ADS)

    Hitomi, K.; Muroi, O.; Shoji, T.; Hiratate, Y.; Ishibashi, H.; Ishii, M.

    2000-07-01

    A wide bandgap compound semiconductor, TlBr, has been investigated as a blue sensitive photodetector material for scintillation detection. The TlBr photodetectors have been fabricated from the TlBr crystals grown by the TMZ method using materials purified by many pass zone refining. The performance of the photodetectors has been evaluated by measuring their leakage current, quantum efficiency, spatial uniformity, direct X-ray detection and scintillation detection characteristics. The photodetectors have shown high quantum efficiency for the blue wavelength region and high spatial uniformity for their optical response. In addition, good direct X-ray detection characteristics with an energy resolution of 4.5 keV FWHM for 22 keV X-rays from a 109Cd radioactive source have been obtained. Detection of blue scintillation from GSO and LSO scintillators irradiated with a 22Na radioactive source has been done successfully by using the photodetectors at room temperature. A clear full-energy peak for 511 keV γ-rays has been obtained with the TlBr photodetector coupled to the LSO scintillator with an energy resolution of 40% FWHM.

  19. Biodegradability of degradable plastic waste.

    PubMed

    Agamuthu, P; Faizura, Putri Nadzrul

    2005-04-01

    Plastic waste constitutes the third largest waste volume in Malaysian municipal solid waste (MSW), next to putrescible waste and paper. The plastic component in MSW from Kuala Lumpur averages 24% (by weight), whereas the national mean is about 15%. The 144 waste dumps in the country receive about 95% of the MSW, including plastic waste. The useful life of the landfills is fast diminishing as the plastic waste stays un-degraded for more than 50 years. In this study the compostability of polyethylene and pro-oxidant additive-based environmentally degradable plastics (EDP) was investigated. Linear low-density polyethylene (LLDPE) samples exposed hydrolytically or oxidatively at 60 degrees C showed that the abiotic degradation path was oxidative rather than hydrolytic. There was a weight loss of 8% and the plastic has been oxidized as shown by the additional carbonyl group exhibited in the Fourier transform infra red (FTIR) Spectrum. Oxidation rate seemed to be influenced by the amount of pro-oxidant additive, the chemical structure and morphology of the plastic samples, and the surface area. Composting studies during a 45-day experiment showed that the percentage elongation (reduction) was 20% for McD samples [high-density polyethylene, (HDPE) with 3% additive] and LL samples (LLDPE with 7% additive) and 18% reduction for totally degradable plastic (TDP) samples (HDPE with 3% additive). Lastly, microbial experiments using Pseudomonas aeroginosa on carbon-free media with degradable plastic samples as the sole carbon source, showed confirmatory results. A positive bacterial growth and a weight loss of 2.2% for degraded polyethylene samples were evident to show that the degradable plastic is biodegradable.

  20. ARAPUCA a new device for liquid argon scintillation light detection

    NASA Astrophysics Data System (ADS)

    Machado, A. A.; Segreto, E.

    2016-02-01

    We present a totally innovative device for the detection of liquid argon scintillation light, that has been named ARAPUCA (Argon R&D Advanced Program at UniCAmp). It is composed of a passive light collector and of active devices. The latters are standard SiPMs that operate at liquid argon temperature, while the passive collector is based on a new technology, never explored in this field before. It is a photon trap, that allows to collect light with extremely high efficiency. The total detection efficiency of the device can be tuned by modifying the ratio between the area of the active devices (SiPM) and the area of the optical window. For example, it will allow to reach a detection efficiency at the level of 1% on a surface of 50 × 50 cm2 with an active coverage of 2 × 2 cm2 (two/three large area SiPM). It is also a cheap device, since the major part of its cost is represented by the active devices. For these reason this appears to be the ideal device for scintillation light detection in large Time Projection Chambers. With appropriate modifications it can be used also in next generation Dark Matter detectors.

  1. Development of a hard x-ray focal plane compton polarimeter: a compact polarimetric configuration with scintillators and Si photomultipliers

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, T.; Vadawale, S. V.; Goyal, S. K.; Mithun, N. P. S.; Patel, A. R.; Shukla, R.; Ladiya, T.; Shanmugam, M.; Patel, V. R.; Ubale, G. P.

    2016-02-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm × 5 mm × 150 mm) which are read by Si Photomultiplier (SiPM). Use of the new generation SiPMs ensures the compactness of the instrument which is essential for the design of focal plane detectors. The expected sensitivity of such polarimetric configuration and complete characterization of the plastic scatterer, specially at lower energies have been discussed in [11, 13]. In this paper, we characterize the CsI(Tl) absorbers coupled to SiPM. We also present the experimental results from the fully assembled configuration of the Compton polarimeter.

  2. X-ray imaging with scintillator-sensitized hybrid organic photodetectors

    NASA Astrophysics Data System (ADS)

    Büchele, Patric; Richter, Moses; Tedde, Sandro F.; Matt, Gebhard J.; Ankah, Genesis N.; Fischer, Rene; Biele, Markus; Metzger, Wilhelm; Lilliu, Samuele; Bikondoa, Oier; MacDonald, J. Emyr; Brabec, Christoph J.; Kraus, Tobias; Lemmer, Uli; Schmidt, Oliver

    2015-12-01

    Medical X-ray imaging requires cost-effective and high-resolution flat-panel detectors for the energy range between 20 and 120 keV. Solution-processed photodetectors provide the opportunity to fabricate detectors with a large active area at low cost. Here, we present a disruptive approach that improves the resolution of such detectors by incorporating terbium-doped gadolinium oxysulfide scintillator particles into an organic photodetector matrix. The X-ray induced light emission from the scintillators is absorbed within hundreds of nanometres, which is negligible compared with the pixel size. Hence, optical crosstalk, a limiting factor in the resolution of scintillator-based X-ray detectors, is minimized. The concept is validated with a 256 × 256 pixel detector with a resolution of 4.75 lp mm-1 at a MTF = 0.2, significantly better than previous stacked scintillator-based flat-panel detectors. We achieved a resolution that proves the feasibility of solution-based detectors in medical applications. Time-resolved electrical characterization showed enhanced charge carrier mobility with increased scintillator filling, which is explained by morphological changes.

  3. Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations

    SciTech Connect

    Sótér, A.; Todoroki, K.; Kobayashi, T.; Barna, D.; Horváth, D.; Hori, M.

    2014-02-15

    The Atomic Spectroscopy and Collisions Using Slow Antiprotons experiment at the Antiproton Decelerator (AD) facility of CERN constructed segmented scintillators to detect and track the charged pions which emerge from antiproton annihilations in a future superconducting radiofrequency Paul trap for antiprotons. A system of 541 cast and extruded scintillator bars were arranged in 11 detector modules which provided a spatial resolution of 17 mm. Green wavelength-shifting fibers were embedded in the scintillators, and read out by silicon photomultipliers which had a sensitive area of 1 × 1 mm{sup 2}. The photoelectron yields of various scintillator configurations were measured using a negative pion beam of momentum p ≈ 1 GeV/c. Various fibers and silicon photomultipliers, fiber end terminations, and couplings between the fibers and scintillators were compared. The detectors were also tested using the antiproton beam of the AD. Nonlinear effects due to the saturation of the silicon photomultiplier were seen at high annihilation rates of the antiprotons.

  4. Characterization of ionospheric scintillation at a geomagnetic equatorial region station

    NASA Astrophysics Data System (ADS)

    Seba, Ephrem Beshir; Gogie, Tsegaye Kassa

    2015-11-01

    In this study, we analyzed ionospheric scintillation at Bahir Dar station, Ethiopia (11.6°N, 37.38°E) using GPS-SCINDA data between August 2010 and July 2011. We found that small scale variation in TEC caused high ionospheric scintillation, rather than large scale variation. We studied the daily and monthly variations in the scintillation index S4 during this year, which showed that scintillation was a post-sunset phenomenon on equinoctial days, with high activity during the March equinox. The scintillation activity observed on solstice days was relatively low and almost constant throughout the day with low post-sunset activity levels. Our analysis of the seasonal and annual scintillation characteristics showed that intense activity occurred in March and April. We also studied the dependence of the scintillation index on the satellite elevation angle and found that scintillation was high for low angles but low for high elevation angles.

  5. Isotopic response with small scintillator based gamma-ray spectrometers

    DOEpatents

    Madden, Norman W.; Goulding, Frederick S.; Asztalos, Stephen J.

    2012-01-24

    The intrinsic background of a gamma ray spectrometer is significantly reduced by surrounding the scintillator with a second scintillator. This second (external) scintillator surrounds the first scintillator and has an opening of approximately the same diameter as the smaller central scintillator in the forward direction. The second scintillator is selected to have a higher atomic number, and thus has a larger probability for a Compton scattering interaction than within the inner region. Scattering events that are essentially simultaneous in coincidence to the first and second scintillators, from an electronics perspective, are precluded electronically from the data stream. Thus, only gamma-rays that are wholly contained in the smaller central scintillator are used for analytic purposes.

  6. Testing Gravity Using Pulsar Scintillation Measurements

    NASA Astrophysics Data System (ADS)

    Yang, Huan; Nishizawa, Atsushi; Pen, Ue-Li

    2016-03-01

    We propose to use pulsar scintillation measurements to test predictions of alternative theories of gravity. Comparing to single-path pulsar timing measurements, the scintillation measurements can achieve a factor of 104 ~105 improvement in timing accuracy, due to the effect of multi-path interference. The self-noise from pulsar also does not affect the interference pattern, where the data acquisition timescale is 103 seconds instead of years. Therefore it has unique advantages in measuring gravitational effect or other mechanisms (at mHz and above frequencies) on light propagation. We illustrate its application in constraining scalar gravitational-wave background and measuring gravitational-wave speed, in which cases the sensitivities are greatly improved with respect to previous limits. We expect much broader applications in testing gravity with existing and future pulsar scintillation observations.

  7. Scintillating-glass-fiber neutron sensors

    NASA Astrophysics Data System (ADS)

    Abel, K. H.; Arthur, R. J.; Bliss, M.; Brite, D. W.; Brodzinski, R. L.; Craig, R. A.; Geelhood, B. D.; Goldman, D. S.; Griffin, J. W.; Perkins, R. W.; Reeder, P. L.; Richey, W. R.; Stahl, K. A.; Sunberg, D. S.; Warner, R. A.; Wogman, N. A.; Weber, M. J.

    1994-12-01

    Cerium-doped lithium-silicate glass fibers have been developed at Pacific Northwest Laboratory (PNL) for use as thermal neutron detectors. By using highly-enriched 6Li, these fibers efficiently capture thermal neutrons and produce scintillation light that can be detected at the ends of the fibers. Advantages of scintillating fibers over 3He or BF 3 proportional tubes include flexibility in geometric configuration, ruggedness in high-vibration environments, and less detector weight for the same neutron sensitivity. This paper describes the performance of these scintillating fibers with regard to count rates, pulse height spectra, absolute efficiencies, and neutron/gamma discrimination. Fibers with light transmission lengths ( {1}/{e}) of greater than 2 m have been produced at PNL. Neutron sensors in fiber form allow development of a variety of neutron detectors packaged in previously unavailable configurations. Brief descriptions of some of the devices already produced are included to illustrate these possibilities.

  8. Refractive scintillation in the interstellar medium

    NASA Astrophysics Data System (ADS)

    Coles, W. A.; Rickett, B. J.; Codona, J. L.; Frehlich, R. G.

    1987-04-01

    The slow variation in the apparent intensity of pulsars on time scales of days to months was recently shown to be due to a large-scale component of interstellar scintillation (Rickett, Coles, and Bourgois). These variations are greater than one would expect if the turbulence spectrum were a simple Kolmogorov power law. It is shown that this large-scale component can be greatly enhanced when the turbulence spectrum has a limiting "inner scale" of the order of 109m. The authors present a solution for the covariance of refractive scintillation of an extended source in an extended medium. The results show that refractive scintillations are also responsible for slow variations in "low-frequency variables".

  9. On the scintillation efficiency of carborane-loaded liquid scintillators for thermal neutron detection

    NASA Astrophysics Data System (ADS)

    Chang, Zheng; Okoye, Nkemakonam C.; Urffer, Matthew J.; Green, Alexander D.; Childs, Kyle E.; Miller, Laurence F.

    2015-01-01

    The scintillation efficiency in response to thermal neutrons was studied by loading different concentrations of carborane (0-8.5 wt%) and naphthalene (0 and 100 g/L) in five liquid organic scintillators. The sample was characterized in Pb and Cd shields under the irradiation of the thermal neutrons from a 252Cf source. A method was developed to extract the net neutron response from the pulse-height spectra. It was found that the order of scintillation efficiencies for both γ-rays and thermal neutrons is as follows: diisopropylnaphthalene>toluene (concentrated solutes)>toluene~pseudocumene~m-xylene. The quench constants, obtained by fitting the Stern-Volmer model to the plots of light output versus carborane concentration, are in the range of 0.35-1.4 M-1 for all the scintillators. The Birks factors, estimated using the specific energy loss profiles of the incident particles, are in the range of 9.3-14 mg cm-2 MeV-1 for all the samples. The light outputs are in the range of 63-86 keV electron equivalents (keVee) in response to thermal neutrons. Loading naphthalene generally promotes the scintillation efficiency of the scintillator with a benzene derivative solvent. Among all the scintillators tested, the diisopropylnaphthalene-based scintillator shows the highest scintillation efficiency, lowest Birks factor, and smallest quench constants. These properties are primarily attributed to the double fused benzene-ring structure of the solvent, which is more efficient to populate to the excited singlet state under ionizing radiation and to transfer the excitation energy to the fluorescent solutes.

  10. Epitaxial InGaAsP/InP photodiode for registration of InP scintillation

    NASA Astrophysics Data System (ADS)

    Luryi, S.; Kastalsky, A.; Gouzman, M.; Lifshitz, N.; Semyonov, O.; Stanacevic, M.; Subashiev, A.; Kuzminsky, V.; Cheng, W.; Smagin, V.; Chen, Z.; Abeles, J. H.; Chan, W. K.; Shellenbarger, Z. A.

    2010-10-01

    Operation of semiconductor scintillators requires optically tight integration of the photoreceiver system on the surface of the scintillator slab. We have implemented an efficient and fast quaternary InGaAsP pin photodiode, epitaxially grown on the surface of an InP scintillator wafer and sensitive to InP luminescence. The diode is characterized by an extremely low room-temperature dark current, about 1 nA/cm2 at the reverse bias of 2 V. The low leakage makes possible a sensitive readout circuitry even though the diode has a large area (1×1 mm2) and therefore large capacitance (50 pF). Results of electrical, optical and radiation testing of the diodes are presented. Detection of individual α-particles and γ-photons is demonstrated.

  11. Development of a Plastic Phoswich for Reaction Studies

    NASA Astrophysics Data System (ADS)

    Thornsberry, C.; Jones, K. L.; Partington, D.; Smith, K.; Febbraro, M.; O'Malley, P.; Kolata, J.; Becchetti, F.; TwinSol Collaboration

    2015-10-01

    In inverse kinematics, proton transfer reactions, such as (d,n), may be used to add a proton to a short-lived ion beam. By detecting the outgoing neutron, it is possible to extract spectroscopic information about the recoil nucleus. Plastic scintillators may be used for detecting these neutrons but are sensitive to gamma rays as well as neutrons, usually resulting in a large background. A clean tag on the recoil particle is often necessary for the removal of significant unwanted background from reactions with low cross sections. A plastic scintillator phoswich (phosphor-sandwich) was developed in order to separate the recoil nucleus from a radioactive ion beam cocktail. This phoswich is comprised of two layers of plastic scintillator, with two different pulse shape characteristics, fused together to produce a single assembly viewed by a PMT. Using pulse shape discrimination (PSD) on the resultant digitized light pulses allows for Z separation at rates of up to 1x106 pps. Since the recoil particle has one extra proton than the beam particle, it is only necessary to have separation in Z. This detector was successfully tested during a development experiment at the University of Notre Dame. An overview of the motivation, development, and analysis of this detector will be present.

  12. The design of the TASD (totally active scintillator detector) prototype

    SciTech Connect

    Mefodiev, A. V. Kudenko, Yu. G.

    2015-12-15

    Totally active and magnetic segmented scintillation neutrino detectors are developed for the nextgeneration accelerator neutrino experiments. Such detectors will incorporate scintillation modules with scintillation counters that form X and Y planes. A single counter is a 7 × 10 × 90 mm{sup 3} scintillation bar with gluedin wavelength-shifting fibers and micropixel avalanche photodiodes. The results of measurements of the parameters of these detectors are presented.

  13. The evolution of scintillating medical detectors

    NASA Astrophysics Data System (ADS)

    Hell, E.; Knüpfer, W.; Mattern, D.

    2000-11-01

    The principle of scintillation detectors has been among the first realizations of radiation detectors. Despite ongoing attempts to switch to direct converting detectors, scintillators have shown great persistence in the field of medical imaging. In radiography, computer tomography and nuclear medicine, a variety of scintillating devices are the 'workhorses' of the clinician today. For radiography, flat X-ray detectors (FDs) with evaporated scintillation layers are at the level of product introduction. However, X-ray image intensifier tubes (XIIs) are competitive and still have features that will be hard to beat in the near future. Although XIIs have disadvantages, they have experienced a significant evolution in robust image quality and cost reduction over the decades. The so-called 'offline' detectors from film to storage phosphors seemed to have reached a plateau since the late 1970s. However, the distinction between on- and offline may soften in the future, because of new readout concepts. Detectors in computer tomography (CT) have evolved from scintillators to gaseous direct converters back to scintillators. Extreme timing requirements and detector modularity have ruled out designs that would rank as `high performance' in other fields. Modern ultra-fast ceramic scintillation detectors are a prerequisite of subsecond CT and leave breathing room for future scan times even below 0.5 s. The field of nuclear medicine is a good example of how difficult it is, to replace a cheap and reliable technology. Since many years, direct converters like CdTe and the likes are discussed to overthrow the regime of NaI:Tl in combination with photomultipliers (PMTs). Both components are well known since the 1950s and have shown remarkable staying power. Still the scintillator with the highest light output, NaI:Tl in combination with the basically noiseless PMT is almost unbeatable in low cost. In combination with modern digital electronics, drawbacks of analog circuitry like

  14. Scintillation index in strong oceanic turbulence

    NASA Astrophysics Data System (ADS)

    Baykal, Yahya

    2016-09-01

    Scintillation index of spherical wave in strongly turbulent oceanic medium is evaluated. In the evaluation, modified Rytov solution and our recent formulation that expresses the oceanic turbulence parameters by the atmospheric turbulence structure constant, are employed. Variations of the scintillation index in strong oceanic turbulence are examined versus the oceanic turbulence parameters such as the rate of dissipation of kinetic energy per unit mass of fluid, the rate of dissipation of mean-squared temperature, viscosity, wavelength, the link length, and the ratio of temperature to salinity contributions to the refractive index spectrum.

  15. Upconverting nanoparticles for optimizing scintillator based detection systems

    DOEpatents

    Kross, Brian; McKisson, John E; McKisson, John; Weisenberger, Andrew; Xi, Wenze; Zom, Carl

    2013-09-17

    An upconverting device for a scintillation detection system is provided. The detection system comprises a scintillator material, a sensor, a light transmission path between the scintillator material and the sensor, and a plurality of upconverting nanoparticles particles positioned in the light transmission path.

  16. Discriminated neutron and X-ray radiography using multi-color scintillation detector

    NASA Astrophysics Data System (ADS)

    Nittoh, Koichi; Takahara, Takeshi; Yoshida, Tadashi; Tamura, Toshiyuki

    1999-06-01

    A new conversion screen Gd 2O 2S:Eu is developed, which emits red light on irradiation by thermal neutrons. By applying this in combination with the currently used Gd 2O 2S:Tb, a green-light scintillator, in the radiography under a neutron + X-ray coexisting field, we can easily separate the neutron image and the X-ray image by simple color-image processing. This technique enables a non-destructive and detailed inspection of industrial products composed both of light elements (water, plastics, etc.) and heavy elements (metals), widening the horizon of new applications.

  17. Wormlike micelle assisted rod coating: a general method for facile fabrication of large-area conductive nanomaterial thin layer onto flexible plastics.

    PubMed

    Xie, Jingyi; Wang, Huan; Bai, Huadong; Yang, Peng; Shi, Mengxue; Guo, Peng; Wang, Chen; Yang, Wantai; Song, Huaihe

    2012-06-27

    Through combined application of wormlike-micelle and rod-coating technique, a general method was demonstrated for the facile reparation of thin transparent conductive films (TCF) of various nanomaterials and their hybrids on flexible plastics. The cetyltrimethylammonium hydroxide (CTAOH)/p-toluenesulfonic acid (CTAT) wormlike micelle system was selected for both the dispersion of different nanomaterials and the enhancement of viscosities of the coating fluids. With the single-walled carbon nanotubes (SWNTs)/wormlike micelle aqueous dispersions as coating fluid, TCFs of SWNTs on flexible poly(ethylene terephthalate) (PET) substrates made by rod-coating method were demonstrated. After doping by immersion into thionyl chloride solution, the sheet resistance of SWNTs thin films, which had a transmittance of about 78%, was as low as 480Ω/sq. This coating method was extended to the preparation of thin films or networks of other materials such as reduced graphene oxide and Ag nanowires. The obtained TCF from Ag nanowire networks has a low sheet resistance of 17Ω/sq, which is comparable to the value of best indium tin oxide (ITO) coating on plastic substrates. Finally, hybrid thin films of different nanomaterials were demonstrated by this method. PMID:22551382

  18. The SNO+ Scintillator Purification Plant and Projected Sensitivity to Solar Neutrinos in the Pure Scintillator Phase

    NASA Astrophysics Data System (ADS)

    Pershing, Teal; SNO+ Collaboration

    2016-03-01

    The SNO+ detector is a neutrino and neutrinoless double-beta decay experiment utilizing the renovated SNO detector. In the second phase of operation, the SNO+ detector will contain 780 tons of organic liquid scintillator composed of 2 g/L 2,5-diphenyloxazole (PPO) in linear alkylbenzene (LAB). In this phase, SNO+ will strive to detect solar neutrinos in the sub-MeV range, including CNO production neutrinos and pp production neutrinos. To achieve the necessary detector sensitivity, a four-part scintillator purification plant has been constructed in SNOLAB for the removal of ionic and radioactive impurities. We present an overview of the SNO+ scintillator purification plant stages, including distillation, water extraction, gas stripping, and metal scavenger columns. We also give the projected SNO+ sensitivities to various solar-produced neutrinos based on the scintillator plant's projected purification efficiency.

  19. Development of scintillator plates with high energy resolution for alpha particles made of GPS scintillator grains

    NASA Astrophysics Data System (ADS)

    Shimaoka, Takehiro; Kaneko, Junichi H.; Izaki, Kenji; Tsubota, Youichi; Higuchi, Mikio; Nishiyama, Shusuke

    2014-01-01

    A scintillator plate with high energy resolution was developed to produce an alpha particle monitor used in nuclear fuel reprocessing plants and mixed plutonium-uranium oxide (MOX) fuel plants. Grains of a Gd2Si2O7 (GPS) scintillator of several 10 to 550 μm were fixed on a glass substrate and were then mechanically polished. By increasing the size of scintillator grains and removing fine powders, the collected light yield and energy resolution for alpha particles were drastically improved. Energy resolution of 9.3% was achieved using average grain size of 91 μm. Furthermore, the ratios between counts in a peak and total counts were improved by more than 60% by the further increase of grain size and adoption of mechanically polished surfaces on both sides. Beta and gamma ray influences were suppressed sufficiently by the thin 100 μm scintillator plates.

  20. Progress in studying scintillator proportionality: Phenomenological model

    SciTech Connect

    Bizarri, Gregory; Cherepy, Nerine; Choong, Woon-Seng; Hull, Giulia; Moses, William; Payne, Sephen; Singh, Jai; Valentine, John; Vasilev, Andrey; Williams, Richard

    2009-04-30

    We present a model to describe the origin of non-proportional dependence of scintillator light yield on the energy of an ionizing particle. The non-proportionality is discussed in terms of energy relaxation channels and their linear and non-linear dependences on the deposited energy. In this approach, the scintillation response is described as a function of the deposited energy deposition and the kinetic rates of each relaxation channel. This mathematical framework allows both a qualitative interpretation and a quantitative fitting representation of scintillation non-proportionality response as function of kinetic rates. This method was successfully applied to thallium doped sodium iodide measured with SLYNCI, a new facility using the Compton coincidence technique. Finally, attention is given to the physical meaning of the dominant relaxation channels, and to the potential causes responsible for the scintillation non-proportionality. We find that thallium doped sodium iodide behaves as if non-proportionality is due to competition between radiative recombinations and non-radiative Auger processes.

  1. High resolution scintillation detector with semiconductor readout

    DOEpatents

    Levin, Craig S.; Hoffman, Edward J.

    2000-01-01

    A novel high resolution scintillation detector array for use in radiation imaging such as high resolution Positron Emission Tomography (PET) which comprises one or more parallelepiped crystals with at least one long surface of each crystal being in intimate contact with a semiconductor photodetector such that photons generated within each crystal by gamma radiation passing therethrough is detected by the photodetector paired therewith.

  2. Ionospheric scintillations associated with equatorial E-region

    NASA Technical Reports Server (NTRS)

    Chandra, H.; Vats, H. O.; Sethia, G.; Deshpande, M. R.; Rastogi, R. G.; Sastri, J. H.

    1978-01-01

    Amplitude scintillations at 40, 140, and 360 MHz recorded at an equatorial station Ootacamund (dip 4 deg N) during the ATS-6 phase II and the ionograms at a nearby station Kodaikanal (dip 3.5 deg N) are examined for the scintillation activity. Various sporadic E events, but not the Es-q, are associated with intense daytime scintillations. There are no scintillations at times of normal E-layer or cusp type of Es. Scintillations are also present at times of night Es.

  3. Liquid Scintillator Production for the NOvA Experiment

    SciTech Connect

    Mufson, S.; Baugh, B.; Bower, C.; Coan, T.; Cooper, J.; Corwin, L.; Karty, J.; Mason, P.; Messier, M. D.; Pla-Dalmau, A.; Proudfoot, M.

    2015-04-15

    The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator as the active detector medium to its near and far detectors. The composition of this scintillator was specifically developed to satisfy NOvA's performance requirements. A rigorous set of quality control procedures was put in place to verify that the incoming components and the blended scintillator met these requirements. The scintillator was blended commercially in Hammond, IN. The scintillator was shipped to the NOvA detectors using dedicated stainless steel tanker trailers cleaned to food grade.

  4. Outward atmospheric scintillation effects and inward atmospheric scintillation effects comparisons for direct detection ladar applications

    NASA Astrophysics Data System (ADS)

    Youmans, Douglas G.

    2014-06-01

    Atmospheric turbulence produces intensity modulation or "scintillation" effects on both on the outward laser-mode path and on the return backscattered radiation path. These both degrade laser radar (ladar) target acquisition, ranging, imaging, and feature estimation. However, the finite sized objects create scintillation averaging on the outgoing path and the finite sized telescope apertures produce scintillation averaging on the return path. We expand on previous papers going to moderate to strong turbulence cases by starting from a 20kft altitude platform and propagating at 0° elevation (with respect to the local vertical) for 100km range to a 1 m diameter diffuse sphere. The outward scintillation and inward scintillation effects, as measured at the focal plane detector array of the receiving aperture, will be compared. To eliminate hard-body surface speckle effects in order to study scintillation, Goodman's M-parameter is set to 106 in the analytical equations and the non-coherent imaging algorithm is employed in Monte Carlo realizations. The analytical equations of the signal-to-noise ratio (SNRp), or mean squared signal over a variance, for a given focal plane array pixel window of interest will be summarized and compared to Monte Carlo realizations of a 1m diffuse sphere.

  5. Cross beam scintillations in non-Kolmogorov medium.

    PubMed

    Baykal, Yahya

    2014-10-01

    For the collimated and focused cross beams, the on-axis scintillation index is evaluated when these beams propagate in weak non-Kolmogorov turbulence. In the limiting cases, our solution correctly reduces to the known Gaussian beam scintillations in Kolmogorov turbulence. For both the collimated and the focused cross beams, large power law exponent of the non-Kolmogorov turbulence is found to result in larger scintillations. Evaluating at a fixed power law exponent, the scintillation index of the collimated (focused) cross beam is higher (lower) than the collimated (focused) Gaussian beam scintillation index. When the asymmetry of the collimated (focused) cross beam increases, the scintillations increase (decrease). At a given cross beam configuration, change in the turbulence parameters varies the scintillations in the same manner for all power law exponent values.

  6. Calibration of the HMS Scintillators in Hall C at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Manrique, Maria; Malace, Simona; Castellanos, Jonathan; Jones, Mark; Kvenlog, Eric; Miller, Charles

    2016-03-01

    Jefferson Laboratory has undergone a multi-year upgrade in order for the accelerator to provide an electron beam with a maximum energy of 12 GeV. To accommodate the high energy beam, a new experimental hall (Hall D) has been built, and the existing halls (A, B, and C) have been upgraded. In Hall C specifically, the Super High Momentum Spectrometer (SHMS) was added and the High Momentum Spectrometer (HMS) was upgraded to sustain the 12 GeV beam. This poster focuses on the re-calibration of the HMS scintillator detector in order for the HMS to be ready to take scientific data, Spring 2016. The detector is made of BC-404 plastic scintillator bars arranged in four planes, both vertically and horizontally, to maximize particle detection/localization. The light produced by the scintillators is detected by XP2262 Photomultiplier Tubes (PMTs) located at both ends of each bar. The detector re-calibration involved checking for and fixing light leaks and gain matching all of the PMTs using a 60Co source to ensure 100% detection efficiency for the particles of interest.

  7. Global morphology of ionospheric F-layer scintillations using FS3/COSMIC GPS radio occultation data

    NASA Astrophysics Data System (ADS)

    Tsai, Lung-Chih; Su, Shin-Yi

    2016-07-01

    The FormoSat-3/ Constellation Observing System for Meteorology, Ionosphere and Climate (FS3/COSMIC) has been proven a successful mission on profiling and modeling of ionospheric electron density by the radio occultation (RO) technique. In this study we report FS3/COSMIC limb-viewing observations of the GPS L-band scintillation since mid 2006 and propose to study F-layer irregularity morphology. Generally the FS3/COSMIC has performed >1000 ionospheric RO observations per day. Most of these observations can provide limb-viewing profiles of S4 scintillation index at dual L-band frequencies. There are a few percentage of FS3/COSMIC RO observations having >0.08 S4 values on average. However, seven identified areas at Central Pacific Area (-20∘~ 20∘dip latitude, 160∘E~130∘W), South American Area (-20∘~ 20∘dip latitude, 100∘W~30∘W), African Area (-20∘~ 20∘dip latitude, 30∘W~50∘E), European Area (30∘~55∘N, 0∘~55∘E), Japan See Area (35∘~55∘N, 120∘~150∘E), Arctic Area (> 65∘dip latitude), and Antarctic Area (< -65∘dip latitude) have been designated to have much higher percentage of strong L-band RO scintillation. During these years in most of the last sunspot cycle from mid 2006 to end 2014 the climatology of scintillations, namely, its variations with each identified area, season, local time, magnetic activity and solar activity have been documented.

  8. The homestake surface-underground scintillators: Initial results

    NASA Technical Reports Server (NTRS)

    Cherry, M. L.; Corbato, S.; Daily, T.; Fenyves, E. J.; Kieda, D.; Lande, K.; Lee, C. K.

    1986-01-01

    The first 70 tons of the 140-ton Large Area Scintillation Detector (LASD) have been operating since Jan. 1985 at a depth of 4850 ft. (4200 m.w.e.) in the Homestake Gold Mine, Lead, S.D. A total of 4 x 10(4) high-energy muons (E sub mu is approx. 2.7 TeV at the surface) have been detected. The remainder of the detector is scheduled to be in operation by the Fall of 1985. In addition, a surface air shower array is under construction. The first 27 surface counters, spaced out over an area of 270' x 500', began running in June, 1985. The LASD performance, the potential of the combined shower array and underground muon experiment for detecting point sources, and the initial results of a search for periodic emission from Cygnus X-3 are discussed.

  9. Strain gradient plasticity analysis of elasto-plastic contact between rough surfaces

    NASA Astrophysics Data System (ADS)

    Song, H.; Van der Giessen, E.; Liu, X.

    2016-11-01

    From a microscopic point of view, the real contact area between two rough surfaces is the sum of the areas of contact between facing asperities. Since the real contact area is a fraction of the nominal contact area, the real contact pressure is much higher than the nominal contact pressure, which results in plastic deformation of asperities. As plasticity is size dependent at size scales below tens of micrometers, with the general trend of smaller being harder, macroscopic plasticity is not suitable to describe plastic deformation of small asperities and thus fails to capture the real contact area and pressure accurately. Here we adopt conventional mechanism-based strain gradient plasticity (CMSGP) to analyze the contact between a rigid platen and an elasto-plastic solid with a rough surface. Flattening of a single sinusoidal asperity is analyzed first to highlight the difference between CMSGP and J2 isotropic plasticity. For the rough surface contact, besides CMSGP, pure elastic and J2 isotropic plasticity analysis is also carried out for comparison. In all cases, the contact area A rises linearly with the applied load, but with a different slope which implies that the mean contact pressures are different. CMSGP produces qualitative changes in the distributions of local contact pressures compared with pure elastic and J2 isotropic plasticity analysis, furthermore, bounded by the two.

  10. Mitigation of Memory Effects in Beta Scintillation Cells for Radioactive Gas Detection

    SciTech Connect

    Seifert, Carolyn E; McIntyre, Justin I; Antolick, Kathryn C; Carman, April J; Cooper, Matthew W; Hayes, James C; Heimbigner, Tom R; Hubbard, C W; Litke, Kevin E; Ripplinger, Mike D; Suarez, Reynold

    2005-08-31

    The Automated Radioxenon Sampler/Analyzer (ARSA) developed at PNNL measures the relative concentrations of xenon isotopes using a coincidence system. Previous tests of the ARSA system have shown that latent radioactivity remains in the plastic cells after evacuation of the gases, leading to a “memory effect” in which the background count rate is dependent on the sample history. The increased background results in lower detection sensitivity. Two possible solutions to the memory effect are explored in this work: depositing a thin layer of metal on the plastic cell (“metallization”), and using an inorganic scintillating cell composed of yttrium aluminum perovskite (YAP). In both cases, the presence of inorganic material at the surface is intended to inhibit the diffusion of gases into the cell walls.

  11. Wavelength-Shifting-Fiber Scintillation Detectors for Thermal Neutron Imaging at SNS

    SciTech Connect

    Clonts, Lloyd G; Cooper, Ronald G; Crow, Lowell; Diawara, Yacouba; Ellis, E Darren; Funk, Loren L; Hannan, Bruce W; Hodges, Jason P; Richards, John D; Riedel, Richard A; Wang, Cai-Lin

    2012-01-01

    We have developed wavelength-Shifting-fiber Scintillator Detector (SSD) with 0.3 m2 area per module. Each module has 154 x 7 pixels and a 5 mm x 50 mm pixel size. Our goal is to design a large area neutron detector offering higher detection efficiency and higher count-rate capability for Time-Of-Flight (TOF) neutron diffraction in Spallation Neutron Source (SNS). A ZnS/6LiF scintillator combined with a novel fiber encoding scheme was used to record the neutron events. A channel read-out-card (CROC) based digital-signal processing electronics and position-determination algorithm was applied for neutron imaging. Neutron-gamma discrimination was carried out using pulse-shape discrimination (PSD). A sandwich flat-scintillator detector can have detection efficiency close to He-3 tubes (about 10 atm). A single layer flat-scintillator detector has count rate capability of 6,500 cps/cm2, which is acceptable for powder diffractometers at SNS.

  12. The neutron detectors based on oxide scintillators for control of fissionable radioactive substances

    NASA Astrophysics Data System (ADS)

    Ryzhikov, V. D.; Grinyov, B. V.; Onyshchenko, G. M.; Piven, L. A.; Lysetska, O. K.; Opolonin, O. D.; Kostioukevitch, S. A.; Smith, C. F.

    2014-09-01

    A large-area X-ray CMOS image sensor (LXCIS) is widely used in mammography, non-destructive inspection, and animal CT. For LXCIS, in spite of weakness such as low spatial and energy resolution, a Indirect method using scintillator like CsI(Tl) or Gd2O2S is still well-used because of low cost and easy manufacture. A photo-diode for X-ray imaging has large area about 50 ~ 200 um as compared with vision image sensors. That is because X-ray has feature of straight and very small light emission of a scintillator. Moreover, notwithstanding several structure like columnar, the scintillator still emit a diffusible light. This diffusible light from scintillator can make spatial crosstalk in X-ray photodiode array because of a large incidence angle. Moreover, comparing with vision image sensors, X-ray sensor doesn't have micro lens for gathering the photons to photo-diode. In this study, we simulated the affection of spatial crosstalk in X-ray sensor by comparing optical sensor. Additionally, the chip, which was fabricated in 0.18 um 1P5M process by Hynix in Korea, was tested to know the effect of spatial crosstalk by changing design parameters. From these works, we found out that spatial crosstalk is affected by pixel pitch, incident angle of photons, and micro lens on each pixels.

  13. Balloon flight test of a Compton telescope based on scintillators with silicon photomultiplier readouts

    NASA Astrophysics Data System (ADS)

    Bloser, P. F.; Legere, J. S.; Bancroft, C. M.; Ryan, J. M.; McConnell, M. L.

    2016-03-01

    We present the results of the first high-altitude balloon flight test of a concept for an advanced Compton telescope making use of modern scintillator materials with silicon photomultiplier (SiPM) readouts. There is a need in the fields of high-energy astronomy and solar physics for new medium-energy gamma-ray (~0.4-10 MeV) detectors capable of making sensitive observations of both line and continuum sources over a wide dynamic range. A fast scintillator-based Compton telescope with SiPM readouts is a promising solution to this instrumentation challenge, since the fast response of the scintillators permits both the rejection of background via time-of-flight (ToF) discrimination and the ability to operate at high count rates. The Solar Compton Telescope (SolCompT) prototype presented here was designed to demonstrate stable performance of this technology under balloon-flight conditions. The SolCompT instrument was a simple two-element Compton telescope, consisting of an approximately one-inch cylindrical stilbene crystal for a scattering detector and a one-inch cubic LaBr3:Ce crystal for a calorimeter detector. Both scintillator detectors were read out by 2×2 arrays of Hamamatsu S11828-3344 MPPC devices. Custom front-end electronics provided optimum signal rise time and linearity, and custom power supplies automatically adjusted the SiPM bias voltage to compensate for temperature-induced gain variations. A tagged calibration source, consisting of ~240 nCi of 60Co embedded in plastic scintillator, was placed in the field of view and provided a known source of gamma rays to measure in flight. The SolCompT balloon payload was launched on 24 August 2014 from Fort Sumner, NM, and spent ~3.75 h at a float altitude of ~123,000 ft. The instrument performed well throughout the flight. After correcting for small (~10%) residual gain variations, we measured an in-flight ToF resolution of ~760 ps (FWHM). Advanced scintillators with SiPM readouts continue to show great promise

  14. Real-time Scintillation Monitoring in Alaska from a Longitudinal Chain of ASTRA's SM-211 GPS TEC and Scintillation Receivers

    NASA Astrophysics Data System (ADS)

    Crowley, G.; Azeem, S. I.; Reynolds, A.; Santana, J.; Hampton, D. L.

    2013-12-01

    Amplitude and phase scintillation can cause serious difficulties for GPS receivers. Intense scintillation can cause loss of lock. High latitude studies generally show that phase scintillation can be severe, but the amplitude scintillation tends to be small. The reason for this is not yet understood. Furthermore, the actual causes of the ionospheric irregularities that produce high latitude scintillation are not well understood. While the gradient drift instability is thought to be important in the F-region, there may be other structures present in either the E- or F-regions. The role of particle precipitation is also not well understood. Four of ASTRA's CASES GPS receivers were deployed in Alaska to demonstrate our ability to map scintillation in realtime, to provide space weather services to GPS users, and to initiate a detailed investigation of these effects. These dual-frequency GPS receivers measure total electron content (TEC) and scintillation. The scintillation monitors were deployed in a longitudinal chain at sites in Kaktovic, Fort Yukon, Poker Flat, and Gakona. Scintillation statistics show phase scintillations to be largest at Kaktovic and smallest at Gakona. We present GPS phase scintillation and auroral emission results from the Alaska chain to characterize the correspondence between scintillation and auroral features, and to investigate the role of high latitude auroral features in driving the phase scintillations. We will also present data showing how phase scintillation can cause other GPS receivers to lose lock. The data and results are particularly valuable because they illustrate some of the challenges of using GPS systems for positioning and navigation in an auroral region like Alaska. These challenges for snowplough drivers were recently highlighted, along with the CASES SM-211 space weather monitor, in a special video in which ASTRA and three other small businesses were presented with an entrepreneurial award from William Shatner (http://youtu.be/bIVKEQH_YPk).

  15. Nonproportionality of Scintillator Detectors: Theory and Experiment

    SciTech Connect

    Payne, Stephen; Cherepy, Nerine; Hull, Giulia; Valentine, John; Moses, William; Choong, Woon-Seng

    2009-08-17

    On the basis of nonproportionality data obtained for several scintillators, we have developed a theory to describe the carrier dynamics to fit the light yield versus electron energy. The theory of Onsager was adapted to explain how the carriers form excitons or sequentially arrive at the activators to promote the ion to an excited state, and the theory of Birks was employed to allow for exciton-exciton annihilation. We then developed a second theory to deduce the degradation in resolution that results from nonproportionality by evoking Landau fluctuations, which are essentially variations in the deposited energy density that occur as the high energy electron travels along its trajectory. In general there is good agreement with the data, in terms of fitting the nonproportionality curves and reproducing the literature values of nonproportionality's contribution to the scintillator resolution. With the resurgence of interest in developing scintillator detectors that have good energy resolution, an improved understanding of nonproportionality has become a crucial matter since it presents the fundamental limit to the achievable resolution. In order to hasten an improved understanding of scintillator nonproportionality, we have constructed an instrument referred to as SLYNCI (Scintillator Light Yield Nonproportionality Compton Instrument). This is a second-generation instrument to the original device developed by Valentine and coworkers, wherein several new principles of operation have served to increase the data rate by an order of magnitude as discussed in detail in References. In the present article, the focus is on a theory to describe the measured electron response, which is the light yield as a function of the electron energy. To do this, we account for transport of carriers and excitons, in terms of how they transfer their energy to the activators with competition from nonradiative decay pathways. This work builds on the original work of Murray and coworkers, and

  16. Development of a Large-Area Ultracold Neutron Detector

    NASA Astrophysics Data System (ADS)

    Stoffel, Jenna; Liu, Chen-Yu; UCN Tau Collaboration

    2015-10-01

    To improve our knowledge in particle physics and cosmology, including big-bang nucleosynthesis, we need a more precise and accurate measurement of the lifetime of free neutrons. Though there have been many attempts to measure the neutron lifetime, discrepancies exist between the two major experimental techniques of the beam and the bottle methods. To resolve this discrepancy, the UCN τ experiment will trap ultracold neutrons (UCNs) to perform lifetime measurements to the 1-second level. To accomplish this goal, we are developing a large-area, high-efficiency UCN detector. We construct a scintillating UCN detector by evaporating a thin film of boron-10 onto an airbrushed layer of zinc sulfide (ZnS); the 10B-coated ZnS scintillating film is then glued to wavelength-shifting plastic, which acts as a light guide to direct photons into modern silicon photomultipliers. This new detector has similar efficiency and background noise as the previously-used ion gas detectors, but can be easily scaled up to cover large areas for many applications. The new detector opens up exciting new ways to study systematic effects, as they hold the key to the interpretation of neutron lifetime.

  17. Nano-Ceramic Coated Plastics

    NASA Technical Reports Server (NTRS)

    Cho, Junghyun

    2013-01-01

    Plastic products, due to their durability, safety, and low manufacturing cost, are now rapidly replacing cookware items traditionally made of glass and ceramics. Despite this trend, some still prefer relatively expensive and more fragile ceramic/glassware because plastics can deteriorate over time after exposure to foods, which can generate odors, bad appearance, and/or color change. Nano-ceramic coatings can eliminate these drawbacks while still retaining the advantages of the plastic, since the coating only alters the surface of the plastic. The surface coating adds functionality to the plastics such as self-cleaning and disinfectant capabilities that result from a photocatalytic effect of certain ceramic systems. These ceramic coatings can also provide non-stick surfaces and higher temperature capabilities for the base plastics without resorting to ceramic or glass materials. Titanium dioxide (TiO2) and zinc oxide (ZnO) are the candidates for a nano-ceramic coating to deposit on the plastics or plastic films used in cookware and kitchenware. Both are wide-bandgap semiconductors (3.0 to 3.2 eV for TiO2 and 3.2 to 3.3 eV for ZnO), so they exhibit a photocatalytic property under ultraviolet (UV) light. This will lead to decomposition of organic compounds. Decomposed products can be easily washed off by water, so the use of detergents will be minimal. High-crystalline film with large surface area for the reaction is essential to guarantee good photocatalytic performance of these oxides. Low-temperature processing (<100 C) is also a key to generating these ceramic coatings on the plastics. One possible way of processing nanoceramic coatings at low temperatures (< 90 C) is to take advantage of in-situ precipitated nanoparticles and nanostructures grown from aqueous solution. These nanostructures can be tailored to ceramic film formation and the subsequent microstructure development. In addition, the process provides environment- friendly processing because of the

  18. Recent Developments In Fast Neutron Detection And Multiplicity Counting With Verification With Liquid Scintillator

    SciTech Connect

    Nakae, L; Chapline, G; Glenn, A; Kerr, P; Kim, K; Ouedraogo, S; Prasad, M; Sheets, S; Snyderman, N; Verbeke, J; Wurtz, R

    2011-09-30

    For many years at LLNL, we have been developing time-correlated neutron detection techniques and algorithms for applications such as Arms Control, Threat Detection and Nuclear Material Assay. Many of our techniques have been developed specifically for the relatively low efficiency (a few percent) attainable by detector systems limited to man-portability. Historically, we used thermal neutron detectors (mainly {sup 3}He), taking advantage of the high thermal neutron interaction cross-sections. More recently, we have been investigating the use of fast neutron detection with liquid scintillators, inorganic crystals, and in the near future, pulse-shape discriminating plastics which respond over 1000 times faster (nanoseconds versus tens of microseconds) than thermal neutron detectors. Fast neutron detection offers considerable advantages, since the inherent nanosecond production time-scales of spontaneous fission and neutron-induced fission are preserved and measured instead of being lost by thermalization required for thermal neutron detectors. We are now applying fast neutron technology to the safeguards regime in the form of fast portable digital electronics as well as faster and less hazardous scintillator formulations. Faster detector response times and sensitivity to neutron momentum show promise for measuring, differentiating, and assaying samples that have modest to very high count rates, as well as mixed fission sources like Cm and Pu. We report on measured results with our existing liquid scintillator array, and progress on the design of a nuclear material assay system that incorporates fast neutron detection, including the surprising result that fast liquid scintillator detectors become competitive and even surpass the precision of {sup 3}He-based counters measuring correlated pairs in modest (kg) samples of plutonium.

  19. Scintillator Pad Detector: Very Front End Electronics. Design and Pre-Series

    NASA Astrophysics Data System (ADS)

    Luengo, S.; Riera, J.; Tortella, S.; Vilasis-Cardona, X.; Gascón, D.; Comerma, A.; Garrido, L.

    2006-10-01

    The SPD (Scintillator Pad Detector) is a part of LHCb calorimeter which is designed to distinguish electrons and photons for this first level trigger. This detector is a plastic scintillator layer, divided in about 6000 cells of different size to obtain better granularity near the beam. Charged particles will produce, and photons will not, ionisation on the scintillator. This ionisation generates a light pulse that is collected by a Wavelength Shifting (WLS) fibre that is twisted inside the scintillator cell. The light is transmitted through a clear fibre to the readout system. For cost reduction, these 6000 cells are divided in groups using a MAPMT of 64 channels for receiving information in the readout system. The signal outing the SPD PMTs is rather unpredictable as a result of the low photostatistics, 20-30 photoelectrons per MIP, and the response of the WLS fibre, which has low decay time. Then, the signal processing must be performed by first integrating the total charge and later subtracting to avoid pile-up. The SPD Readout system is performed by an ASIC which integrates the signal, makes the pile-up compensation, and compares the level obtained to a programmable threshold (distinguishing electrons and photons), an FPGA which programmes the ASIC thresholds and pile-up subtraction and finally LVDS serializers, in order to send information to the first level trigger system. The design of the VFE unit takes into account not only mechanical constraints, as a result of the little space for the readout electronics but also the radiation quote expected in the environment and the distance between the VFE electronics and the racks were information is sent.

  20. Performance of very thin Gd2SiO5 scintillator bars for the LHCf experiment

    NASA Astrophysics Data System (ADS)

    Suzuki, T.; Kasahara, K.; Kawade, K.; Murakami, T.; Masuda, K.; Sako, T.; Torii, S.

    2013-01-01

    To increase the radiation resistivity of the calorimeter, the LHCf group plans to replace its plastic scintillator with Gd2SiO5 (GSO) scintillator. In this report, we present the basic performance of very thin GSO scintillator bars that will replace the scintillating fibers employed as the position sensitive part of the current LHCf detector. The size of a bar is 1 mm × 1 mm × 40 mm. White acrylic paint was painted on one group of GSO bars and a second group was unpainted. After observing a clear peak of cosmic ray muons corresponding to 3 to 4 photoelectrons, a quantitative test was performed by using a 290 MeV/n carbon beam at HIMAC in Japan. The non-painted bars have less position dependence of light collection efficiency (effective attenuation length is about 140 mm) and less piece-to-piece variation. The unpainted bars show about 8% cross talk between adjacent bars which is larger than the painted ones. However, for estimating the center of a cascade shower inside the calorimeter, uniformity of light collection is more important than cross talk, so we have decided to use non-painted bars in the LHCf detector. A simulation of a 100 GeV electron injected in the center of the detector shows that position dependence and cross talk cause only a 0.04 mm shift of the shower centroid without any correction applied. This shows that these effects are relatively small compared to the uncertainty of the beam center position which was 1 mm for the LHCf experiments already performed at √s =7 TeV.

  1. Recent Developments in Fast Neutron Detection and Multiplicity Counting with Liquid Scintillator

    NASA Astrophysics Data System (ADS)

    Nakae, L. F.; Chapline, G. F.; Glenn, A. M.; Kerr, P. L.; Kim, K. S.; Ouedraogo, S. A.; Prasad, M. K.; Sheets, S. A.; Snyderman, N. J.; Verbeke, J. M.; Wurtz, R. E.

    2011-12-01

    For many years, LLNL researchers have been developing time-correlated neutron detection techniques and algorithms for applications such as Arms Control, Threat Detection and Nuclear Material Assay. Many of the techniques have been developed specifically for the relatively low efficiency (a few percent) attainable by detector systems limited to man-portability. Historically, thermal neutron detectors (mainly 3He) were used, taking advantage of the high thermal neutron interaction cross sections. More recently, we have been investigating the use of fast neutron detection with liquid scintillators, inorganic crystals, and in the near future, pulse-shape discriminating plastics that respond over 1000 times faster (ns versus tens of μs) than thermal neutron detectors. Fast neutron detection offers considerable advantages since the inherent ns production timescales of spontaneous fission and neutron-induced fission are preserved and measured instead of being lost by thermalization required for thermal neutron detectors. We are now applying fast neutron technology to the safeguards regime in the form of fast portable digital electronics as well as faster and less hazardous scintillator formulations. Faster detector response times and sensitivity to neutron momentum show promise for measuring, differentiating, and assaying samples that have modest to very high count rates, as well as mixed fission sources like Cm and Pu. We report on measured results with our existing liquid scintillator array and progress on the design of a nuclear material assay system that incorporates fast neutron detection, including the surprising result that fast liquid scintillator detectors become competitive and even surpass the precision of 3He-based counters measuring correlated pairs in modest (kg) samples of plutonium.

  2. Scintillator Pad Detector: Very Front End Electronics. Design and Pre-Series

    SciTech Connect

    Luengo, S.; Riera, J.; Tortella, S.; Vilasis-Cardona, X.; Gascon, D.; Comerma, A.; Garrido, L.

    2006-10-27

    The SPD (Scintillator Pad Detector) is a part of LHCb calorimeter which is designed to distinguish electrons and photons for this first level trigger. This detector is a plastic scintillator layer, divided in about 6000 cells of different size to obtain better granularity near the beam. Charged particles will produce, and photons will not, ionisation on the scintillator. This ionisation generates a light pulse that is collected by a Wavelength Shifting (WLS) fibre that is twisted inside the scintillator cell. The light is transmitted through a clear fibre to the readout system. For cost reduction, these 6000 cells are divided in groups using a MAPMT of 64 channels for receiving information in the readout system. The signal outing the SPD PMTs is rather unpredictable as a result of the low photostatistics, 20-30 photoelectrons per MIP, and the response of the WLS fibre, which has low decay time. Then, the signal processing must be performed by first integrating the total charge and later subtracting to avoid pile-up. The SPD Readout system is performed by an ASIC which integrates the signal, makes the pile-up compensation, and compares the level obtained to a programmable threshold (distinguishing electrons and photons), an FPGA which programmes the ASIC thresholds and pile-up subtraction and finally LVDS serializers, in order to send information to the first level trigger system. The design of the VFE unit takes into account not only mechanical constraints, as a result of the little space for the readout electronics but also the radiation quote expected in the environment and the distance between the VFE electronics and the racks were information is sent.

  3. Plastics processing: statistics, current practices, and evaluation.

    PubMed

    Cooke, F

    1993-11-01

    The health care industry uses a huge quantity of plastic materials each year. Much of the machinery currently used, or supplied, for plastics processing is unsuitable for use in a clean environment. In this article, the author outlines the reasons for the current situation and urges companies to re-examine their plastic-processing methods, whether performed in-house or subcontracted out. Some of the factors that should be considered when evaluating plastics-processing equipment are outlined to assist companies in remaining competitive and complying with impending EC regulations on clean room standards for manufacturing areas.

  4. Monte Carlo investigations of the effect of beam divergence on thick, segmented crystalline scintillators for radiotherapy imaging

    PubMed Central

    Wang, Yi; El-Mohri, Youcef; Antonuk, Larry E.; Zhao, Qihua

    2010-01-01

    The use of thick segmented scintillators in electronic portal imagers offers the potential for significant improvement in x-ray detection efficiency compared to conventional phosphor screens. Such improvement substantially increases the detective quantum efficiency (DQE), leading to the possibility of achieving soft-tissue visualization at clinically-practical (i.e. low) doses using megavoltage (MV) cone-beam computed tomography. While these DQE increases are greatest at zero spatial frequency, they are diminished at higher frequencies as a result of degradation of spatial resolution due to lateral spreading of secondary radiation within the scintillator – an effect that is more pronounced for thicker scintillators. The extent of this spreading is even more accentuated for radiation impinging the scintillator at oblique angles of incidence due to beam divergence. In this paper, Monte Carlo simulations of radiation transport, performed to investigate and quantify the effects of beam divergence on the imaging performance of MV imagers based on two promising scintillators (BGO and CsI:T1), are reported. In these studies, 10 – 40 mm thick scintillators, incorporating low-density polymer, or high-density tungsten septal walls were examined for incident angles corresponding to that encountered at locations up to ~15 cm from the central beam axis (for an imager located 130 cm from a radiotherapy x-ray source). The simulations demonstrate progressively more severe spatial resolution degradation (quantified in terms of the effect on modulation transfer function) as a function of increasing angle of incidence (as well as of scintillator thickness). Since the noise power behavior was found to be largely independent of incident angle, the dependence of the DQE on incident angle is therefore primarily determined by the spatial resolution. The observed DQE degradation suggests that 10 mm thick scintillators are not strongly affected by beam divergence for detector areas up

  5. Development of a new scintillation-trigger detector for the MTV experiment using aluminum-metallized film tape

    NASA Astrophysics Data System (ADS)

    Sakamoto, Yuko; Ozaki, Sachi; Tanaka, Saki; Tanuma, Ryosuke; Yoshida, Tatsuru; Murata, Jiro

    2014-09-01

    A new type of trigger-scintillation counter array designed for the MTV experiment at TRIUMF-ISAC has been developed, using aluminum-metallized film tape for wrapping. The MTV experiment aims to perform the finest precision test of time reversal symmetry in nuclear beta decay. In that purpose, we search non-zero T-Violating transverse polarization of electrons emitted from polarized Li-8 nuclei. It uses a cylindrical drift chamber (CDC) as the main electron-tracking detector. The trigger-scintillation counter consists of 12-segmented 1 mm thick 300 mm long thin plastic scintillation counters. This counter is placed inside the CDC to generate a trigger signal. The required assembling precision of +-0.5 mm was a tricky point when we tried to use conventional total reflection mode. Indeed, produce an air-layer surrounding the scintillating bar to keep good light transmission was the main issue. For this reason, we tried to use a new wrapping material made of metallized-aluminum tape, which has a good mirror-like reflecting surface on both sides of the tape. Through this report, we will compare detection efficiency and light attenuation between conventional and new wrapping materials.

  6. A large acceptance scintillator detector with wavelength shifting fibre readout for search of η-nucleus bound states

    NASA Astrophysics Data System (ADS)

    Betigeri, M. G.; Biswas, P. K.; Budzanowski, A.; Chatterjee, A.; Jahn, R.; Guha, S.; Hawranek, P.; Jain, B. K.; Jawale, S. B.; Jha, V.; Kilian, K.; Kliczewski, S.; Kirillov, Da.; Kirillov, Di.; Kolev, D.; Kravcikova, M.; Kutsarova, T.; Lesiak, M.; Lieb, J.; Machner, H.; Magiera, A.; Maier, R.; Martinska, G.; Nedev, S.; Piskunov, N.; Prasuhn, D.; Protić, D.; Ritman, J.; von Rossen, P.; Roy, B. J.; Shukla, P.; Sitnik, I.; Siudak, R.; Tsenov, R.; Ulicny, M.; Urban, J.; Vankova, G.; GEM Collaboration

    2007-07-01

    A large acceptance scintillator detector with wavelength shifting optical fibre readout has been designed and built to detect the decay particles of η-nucleus bound system (the so-called η-mesic nuclei), namely, protons and pions. The detector, named as ENSTAR detector, consists of 122 pieces of plastic scintillator of various shapes and sizes, which are arranged in a cylindrical geometry to provide particle identification, energy loss and coarse position information for these particles. A solid angle coverage of ˜95% of total 4 π is obtained in the present design of the detector. Monte Carlo phase space calculations performed to simulate the formation and decay of η-mesic nuclei suggest that its decay particles, the protons and pions are emitted with an opening angle of 150±20∘, and with energies in the range of 25-300 and 225-450 MeV, respectively. The detailed GEANT simulations show that ˜80 % of the decay particles (protons and pions) can be detected within ENSTAR. Several test measurements using alpha source, cosmic-ray muons, etc. have been carried out to study the response of ENSTAR scintillator pieces. The in-beam tests of fully assembled detector with proton beam of momentum 870 MeV/c from the Cooler synchrotron COSY have been performed. The test results show that the scintillator fibre design chosen for the detector has performed satisfactorily well. The present article describes the detector design, simulation studies, construction details and test results.

  7. Scintillating 99Tc Selective Ion Exchange Resins

    SciTech Connect

    Mitchell Greenhalgh; Richard D. Tillotson

    2012-07-01

    Scintillating technetium (99Tc) selective ion exchange resins have been developed and evaluated for equilibrium capacities and detection efficiencies. These resins can be utilized for the in-situ concentration and detection of low levels of pertechnetate anions (99TcO4-) in natural waters. Three different polystyrene type resin support materials were impregnated with varying amounts of tricaprylmethylammonium chloride (Aliquat 336) extractant, several different scintillating fluors and wavelength shifters. The prepared resins were contacted batch-wise to equilibrium over a wide range of 99TcO4- concentrations in natural water. The measured capacities were used to develop Langmuir adsorption isotherms for each resin. 99Tc detection efficiencies were determined and up to 71.4 ± 2.6% was achieved with some resins. The results demonstrate that a low level detection limit for 99TcO4- in natural waters can be realized.

  8. Neutron detection with single crystal organic scintillators

    SciTech Connect

    Zaitseva, N; Newby, J; Hamel, S; Carman, L; Faust, M; Lordi, V; Cherepy, N; Stoeffl, W; Payne, S

    2009-07-15

    Detection of high-energy neutrons in the presence of gamma radiation background utilizes pulse-shape discrimination (PSD) phenomena in organics studied previously only with limited number of materials, mostly liquid scintillators and single crystal stilbene. The current paper presents the results obtained with broader varieties of luminescent organic single crystals. The studies involve experimental tools of crystal growth and material characterization in combination with the advanced computer modeling, with the final goal of better understanding the relevance between the nature of the organic materials and their PSD properties. Special consideration is given to the factors that may diminish or even completely obscure the PSD properties in scintillating crystals. Among such factors are molecular and crystallographic structures that determine exchange coupling and exciton mobility in organic materials and the impurity effect discussed on the examples of trans-stilbene, bibenzyl, 9,10-diphenylanthracene and diphenylacetylene.

  9. Fast scintillation counter system and performance

    NASA Technical Reports Server (NTRS)

    Sasaki, H.; Nishioka, A.; Ohmori, N.; Kusumose, M.; Nakatsuka, T.; Horiki, T.; Hatano, Y.

    1985-01-01

    An experimental study of the fast scintillation counter (FS) system to observe a shower disk structure at Mt. Norikura is described, especially the system performance and a pulse wave-form by a single charge particles. The photomultiplier tube (PT) pulse appears at the leading edge of the main pulse. To remove this PT-pulse from the main pulse, the frame of the scintillator vessel was changed. The fast triggering system was made to decrease the dead time which came from the use of the function of the self triggering of the storage oscilloscope (OSC). To provide a new field on the multi-parameter study of the cosmic ray showers, the system response of the FS system also improved as a result of many considerations.

  10. Internet access to data for scintillation compounds

    SciTech Connect

    Moses, W.W.; West, A.C.; Derenzo, S.E.

    1995-09-01

    The LBL Pulsed X-Ray Facility has scintillation data on a large variety of inorganic scintillators. We offer this information on all compounds that we have tested. The only restrictions/favors that we ask users of this data are: (1) The data is intended for research use and may not be sold; (2) If any portion of the data is used in a publication, that the following text appear somewhere in the publication: {open_quotes}This work was supported in part by the Director, Office of Energy Research, Office of Health and Environmental Research, Medical Applications and Biophysical Research Division of the U.S. Department of Energy under contract No. DE-AC03-76SF00098, and in part by Public Health Service Grant No. R01 CA48002 awarded by the National Cancer Institutes, Department of Health and Human Services.{close_quotes}.

  11. Codoped direct-gap semiconductor scintillators

    DOEpatents

    Derenzo, Stephen Edward; Bourret-Courchesne, Edith; Weber, Marvin J.; Klintenberg, Mattias K.

    2008-07-29

    Fast, bright inorganic scintillators at room temperature are based on radiative electron-hole recombination in direct-gap semiconductors, e.g. CdS and ZnO. The direct-gap semiconductor is codoped with two different impurity atoms to convert the semiconductor to a fast, high luminosity scintillator. The codopant scheme is based on dopant band to dopant trap recombination. One dopant provides a significant concentration of carriers of one type (electrons or holes) and the other dopant traps carriers of the other type. Examples include CdS:In,Te; CdS:In,Ag; CdS:In,Na; ZnO:Ga,P; ZnO:Ga,N; ZnO:Ga,S; and GaN:Ge,Mg.

  12. Codoped direct-gap semiconductor scintillators

    DOEpatents

    Derenzo, Stephen E.; Bourret-Courchesne, Edith; Weber, Marvin J.; Klintenberg, Mattias K.

    2006-05-23

    Fast, bright inorganic scintillators at room temperature are based on radiative electron-hole recombination in direct-gap semiconductors, e.g. CdS and ZnO. The direct-gap semiconductor is codoped with two different impurity atoms to convert the semiconductor to a fast, high luminosity scintillator. The codopant scheme is based on dopant band to dopant trap recombination. One dopant provides a significant concentration of carriers of one type (electrons or holes) and the other dopant traps carriers of the other type. Examples include CdS:In,Te; CdS:In,Ag; CdS:In,Na; ZnO:Ga,P; ZnO:Ga,N; ZnO:Ga,S; and GaN:Ge,Mg.

  13. Transparent Ceramic Scintillator Fabrication, Properties and Applications

    SciTech Connect

    Cherepy, N J; Kuntz, J D; Roberts, J J; Hurst, T A; Drury, O B; Sanner, R D; Tillotson, T M; Payne, S A

    2008-08-24

    Transparent ceramics offer an alternative to single crystals for scintillator applications such as gamma ray spectroscopy and radiography. We have developed a versatile, scaleable fabrication method, using Flame Spray Pyrolysis (FSP) to produce feedstock which is readily converted into phase-pure transparent ceramics. We measure integral light yields in excess of 80,000 Ph/MeV with Cerium-doped Garnets, and excellent optical quality. Avalanche photodiode readout of Garnets provides resolution near 6%. For radiography applications, Lutetium Oxide offers a high performance metric and is formable by ceramics processing. Scatter in transparent ceramics due to secondary phases is the principal limitation to optical quality, and afterglow issues that affect the scintillation performance are presently being addressed.

  14. Development of a scintillation-fiber detector for real-time particle tracking

    NASA Astrophysics Data System (ADS)

    Lo Presti, D.; Bonanno, D. L.; Longhitano, F.; Pugliatti, C.; Russo, G. V.; Aiello, S.; Cirrone, G. A. P.; Giordano, V.; Leonora, E.; Randazzo, N.; Romano, F.; Russo, M.; Sipala, V.; Stancampiano, C.; Reito, S.

    2013-04-01

    The prototype of the OFFSET (Optical Fiber Folded Scintillating Extended Tracker) tracker is presented. It exploits a novel system for particle tracking, designed to achieve real-time imaging, large detection areas, and a high spatial resolution especially suitable for use in medical diagnostics. The main results regarding the system architecture have been used as a demonstration of the technique which has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The prototype of this tracker, presented in this paper, has a 20 × 20 cm2 sensitive area, consisting of two crossed ribbons of 500 micron square scintillating fibers. The track position information is extracted in real time in an innovative way, using a reduced number of read-out channels to obtain very large detection area with moderate enough costs and complexity. The performance of the tracker was investigated using beta sources, cosmic rays, and a 62 MeV proton beam.

  15. Nanophosphor composite scintillators comprising a polymer matrix

    DOEpatents

    Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David

    2010-11-16

    An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.

  16. Simulating Silicon Photomultiplier Response to Scintillation Light

    PubMed Central

    Jha, Abhinav K.; van Dam, Herman T.; Kupinski, Matthew A.; Clarkson, Eric

    2015-01-01

    The response of a Silicon Photomultiplier (SiPM) to optical signals is affected by many factors including photon-detection efficiency, recovery time, gain, optical crosstalk, afterpulsing, dark count, and detector dead time. Many of these parameters vary with overvoltage and temperature. When used to detect scintillation light, there is a complicated non-linear relationship between the incident light and the response of the SiPM. In this paper, we propose a combined discrete-time discrete-event Monte Carlo (MC) model to simulate SiPM response to scintillation light pulses. Our MC model accounts for all relevant aspects of the SiPM response, some of which were not accounted for in the previous models. We also derive and validate analytic expressions for the single-photoelectron response of the SiPM and the voltage drop across the quenching resistance in the SiPM microcell. These analytic expressions consider the effect of all the circuit elements in the SiPM and accurately simulate the time-variation in overvoltage across the microcells of the SiPM. Consequently, our MC model is able to incorporate the variation of the different SiPM parameters with varying overvoltage. The MC model is compared with measurements on SiPM-based scintillation detectors and with some cases for which the response is known a priori. The model is also used to study the variation in SiPM behavior with SiPM-circuit parameter variations and to predict the response of a SiPM-based detector to various scintillators. PMID:26236040

  17. Studies of NICADD Extruded Scintillator Strips

    SciTech Connect

    Dychkant, Alexandre; et al.

    2005-03-01

    About four hundred one meter long, 10 cm wide and 5 mm thick extruded scintillating strips were measured at four different points. The results of measurements strip responses to a radioactive source {sup 90}Sr are provided, and details of strip choice, preparation, and method of measurement are included. This work was essential for prototyping a tail catcher and muon tracker for a future international electron positron linear collider detector.

  18. Sorohalide scintillators, phosphors, and uses thereof

    DOEpatents

    Yang, Pin; Deng, Haoran; Doty, F. Patrick; Zhou, Xiaowang

    2016-05-10

    The present invention relates to sorohalide compounds having formula A.sub.3B.sub.2X.sub.9, where A is an alkali metal, B is a rare earth metal, and X is a halogen. Optionally, the sorohalide includes a dopant D. Such undoped and doped sorohalides are useful as scintillation materials or phosphors for any number of uses, including for radiation detectors, solid-state light sources, gamma-ray spectroscopy, medical imaging, and drilling applications.

  19. Characteristics of Yerevan High Transparency Scintillators

    SciTech Connect

    Zorn, Carl; Asryan, Gegham; Egiyan, Kim; Tarverdyan, M.; Amaryan, Moscov; Amaryan, Moskov; Demirchyan, Raphael; Stepanyan, Stepan; Burkert, Volker; Sharabian, Youri

    1992-08-01

    Optical transmission, light output and time characteristics are given for long scintillator strips fabricated at the Yerevan Physics Institute using the extrusion method. It is shown that at 45% relative (to anthracene) light output, good transmission (2.5/2.9 m attenuation length with photomultiplier direct readout and 3/3.5 m attenuation length fiber readout) and time characteristics (average decay time 2.8 nsec) were obtained.

  20. Improved Neutron Scintillators Based on Nanomaterials

    SciTech Connect

    Dennis Friesel, PhD

    2008-06-30

    The development work conducted in this SBIR has so far not supported the premise that using nano-particles in LiFZnS:Ag foils improves their transparency to 420 (or other frequency) light. This conclusion is based solely on the light absorption properties of LiFZnS foils fabricated from nano- and from micro-particles. Furthermore, even for the case of the Gd{sub 2}O{sub 3} foils, the transmission of 420 nm light gained by using nano-particles all but disappears as the foil thickness is increased beyond about 0.2 mm, a practical scintillator thickness. This was not immediately apparent from the preliminary study since no foils thicker than about 0.04 mm were produced. Initially it was believed that the failure to see an improvement by using nano-particles for the LiFZnS foils was caused by the clumping of the particles in Toluene due to the polarity of the ZnS particles. However, we found, much to our surprise, that nano-particle ZnS alone in polystyrene, and in Epoxy, had worse light transmission properties than the micro-particle foils for equivalent thickness and density foils. The neutron detection measurements, while disappointing, are attributable to our inability to procure or fabricate Bulk Doped ZnS nanoparticles. The cause for the failure of nano-particles to improve the scintillation light, and hence improved neutron detection efficiency, is a fundamental one of light scattering within the scintillator. A consequence of PartTec's documentation of this is that several concepts for the fabrication of improved {sup 6}LiFZnS scintillators were formulated that will be the subject of a future SBIR submission.

  1. Boron-Loaded Silicone Rubber Scintillators

    SciTech Connect

    Bell, Z.W.; Maya, L.; Brown, G.M.; Sloop, F.V.Jr

    2003-05-12

    Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon response were obtained, and although the light output was found to be much poorer than from samples in which boron was dissolved, the higher boron concentrations enabled essentially 100% neutron absorption in only a few millimeters' thickness of rubber.

  2. GPS scintillations over Vietnam on April 2006

    NASA Astrophysics Data System (ADS)

    Alfonsi, Lucilla; Spogli, Luca; Tong, Jenna R.; de Franceschi, Giorgiana; Romano, Vincenzo; Bourdillon, Alain; Le Huy, Minh; Mitchell, Cathryn N.

    2010-05-01

    In Vietnam, at Hue (16.4°N, 107.6°E) and Hoc Mon (10.9°N, 106.6°E), are located two GPS receivers specially modified for recording, at a sampling rate of 50 Hz, the phase and the amplitude of the L1 signal and the Total Electron Content (TEC) from L1 and L2. In April 2006 both the receivers have observed post-sunset scintillation inhibition when moderate magnetic storms occurred. These measurements together with a 3D plus time imaging of the ionosphere produced by the Multi-Instrument Data Analysis System (MIDAS) have revealed interesting features that will be described in the present paper. In particular, the results confirm the role of the ring current on the generation of the equatorial F layer irregularities of scale size from less than a hundred meters to a few kilometers, highlighting also its important role in inhibiting scintillation during the storm. The characterization of the different conditions of the Interplanetary Magnetic Field (IMF) will be illustrated, as well, to attempt a description of the scintillation effects over a region scarcely investigated in the open literature.

  3. Scintillators with potential to supersede lanthanum bromide

    SciTech Connect

    Cherepy, Nerine; Payne, Steven; Aszatlos, Steve; Hull, Giulia; Kuntz, J.; Niedermayr, Tom; Pimputkar, S.; Roberts, J.; Sanner, R.; Tillotson, T.; van Loef, Edger; Wilson, Cody; Shah, Kanai; Roy, U.; Hawrami, R.; Burger, Arnold; Boatner, Lynn; Choong, Woon-Seng; Moses, William

    2009-06-01

    New scintillators for high-resolution gamma ray spectroscopy have been identified, grown and characterized. Our development efforts have focused on two classes of high light yield materials: Europium-doped alkaline earth halides and Cerium-doped garnets. Of the halide single crystals we have grown by the Bridgman method - SrI{sub 2}, CaI{sub 2}, SrBr{sub 2}, BaI{sub 2} and BaBr{sub 2} - SrI{sub 2} is the most promising. SrI{sub 2}(Eu) emits into the Eu{sup 2+} band, centered at 435 nm, with a decay time of 1.2 {micro}s and a light yield of up to 115,000 photons/MeV. It offers energy resolution better than 3% FWHM at 662 keV, and exhibits excellent light yield proportionality. Transparent ceramics fabrication allows production of Gadolinium- and Terbium-based garnets which are not growable by melt techniques due to phase instabilities. While scintillation light yields of Cerium-doped ceramic garnets are high, light yield non-proportionality and slow decay components appear to limit their prospects for high energy resolution. We are developing an understanding of the mechanisms underlying energy dependent scintillation light yield non-proportionality and how it affects energy resolution. We have also identified aspects of optical design that can be optimized to enhance energy resolution.

  4. Detecting dark matter with scintillating bubble chambers

    NASA Astrophysics Data System (ADS)

    Zhang, Jianjie; Dahl, C. Eric; Jin, Miaotianzi; Baxter, Daniel

    2016-03-01

    Threshold based direct WIMP dark matter detectors such as the superheated bubble chambers developed by the PICO experiment have demonstrated excellent electron-recoil and alpha discrimination, excellent scalability, ease of change of target fluid, and low cost. However, the nuclear-recoil like backgrounds have been a limiting factor in their dark matter sensitivity. We present a new type of detector, the scintillating bubble chamber, which reads out the scintillation pulse of the scattering events as well as the pressure, temperature, acoustic traces, and bubble images as a conventional bubble chamber does. The event energy provides additional handle to discriminate against the nuclear-recoil like backgrounds. Liquid xenon is chosen as the target fluid in our prototyping detector for its high scintillation yield and suitable vapor pressure which simplifies detector complexity. The detector can be used as an R&D tool to study the backgrounds present in the current PICO bubble chambers or as a prototype for standalone dark matter detectors in the future. Supported by DOE Grant DE-SC0012161.

  5. Chloride, bromide and iodide scintillators with europium

    DOEpatents

    Zhuravleva, Mariya; Yang, Kan

    2016-09-27

    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  6. Sillicon Photomultiplier and Scintillator Bar Systems

    NASA Astrophysics Data System (ADS)

    Shelor, Mark; Elizondo, Leonardo; Ritt, Stefan

    2016-03-01

    To analyze extraterrestrial cosmic rays via precise measurements of airshower axes directions of penetrating particles such as muons, we constructed a model detector consisting of two 1-meter long scintillator bars. Each bar is fitted with green wavelength shifting fibers to modulate input for two silicon photomultiplier (SiPM) light detectors to record light produced by cosmic rays via scintillation. The purpose of the experiment is to determine the performance of these devices. Two makes of SiPMs were evaluated - from AdvanSiD and Hamamatsu. In order to filter out noise, timing measurements of the apparatus were performed under several trigger conditions such as coincidence trigger with 2 photomultiplier detectors, as well as SiPM detector arrays in self-triggered mode. The DRS4 Digitizer 4-channel fast waveform sampler digitized SiPM detector waveforms. Signals were analyzed with the CERN PAW package. The speed of light in the scintillator using the SiPM modules was found to be approximately 66% of the speed of light in a vacuum which is in accordance with the index of refraction for the fibers given by the manufacturer's specifications. The results of our timing measurements would be presented. Dept. of Ed. Title V Grant PO31S090007.

  7. Interstellar Scintillation of Extragalactic Radio Sources

    NASA Astrophysics Data System (ADS)

    Rickett, Barney

    1998-05-01

    Interstellar scintillation (ISS) causes a Galactic seeing problem for radio astronomy. Thus the flux density from a very compact radio source appears to scintillate on a time scale that ranges from days to minutes depending on the wavelength and Galactic path length. I will review the observed variations from various sources, which are among the most compact cores of active galactic nuclei (AGN). An ISS interpretation of the observed variations yields estimates of the source sizes in the range 0.01 to 10 milliarcsec, often much smaller than the resolution from earth-based VLBI. The recognition of such variations as apparent reduces the implied brightness temperature by a factor as large as one million, compared to the extreme values deduced by interpreting the variations as intrinsic. Some such intraday variable sources also exhibit partially correlated variations in their polarized flux and angle. The changes in interstellar Faradya rotation are too slow to cause such variations by many orders of magnitude. I will report on attempts to model the polarized flux variations as due to independent ISS from polarized components with intrinsic polarization structure in the source at a level of tens of microarcseconds. I will also discuss how Frail et al. (Nature, 389, 261, 1997) used interstellar scintillation to estimate the size of the expanding fireball in the radio afterglow of gamma-ray burst 970508.

  8. Characterization of Ionospheric Scintillation Using Simultaneous Formosat-3/COSMIC Radio Occultation Observations and AFRL SCINDA Ground Scintillation Measurements

    NASA Astrophysics Data System (ADS)

    Starks, M. J.; Lin, C. S.; Groves, K. M.; Pedersen, T. R.; Basu, S.; Syndergaard, S.; Rocken, C.

    2007-05-01

    Ionospheric scintillation at low latitudes has been studied using ionospheric radio occultation (RO) measurements by the FORMOSAT-3/COSMIC micro-satellites in conjunction with ground-based data from the Scintillation Network Decision Aid (SCINDA) station at Kwajalein Atoll. The Air Force Research Laboratory has developed the SCINDA network for monitoring low-latitude ionospheric total electron content (TEC) and scintillation associated with equatorial spread F. The network currently consists of sixteen stations distributed around the globe and the data have been used to conduct numerous studies on the characteristics and climatology of equatorial scintillation. The present study focuses on COSMIC RO and SCINDA data during the three COSMIC campaigns in 2006. Radio occultation events are selected by requiring that ionospheric scintillation was detected by the SCINDA VHF scintillation monitor at Kwajalein, and that the occultation ray path intersected the Kwajalein longitude below the satellite altitude, which varied from 500 to 800 km for the six FORMOSAT-3 satellites. In order to exclude tropospheric effects, only GPS signal amplitudes from FORMOSAT-3 with ray path tangent altitudes above 100 km are considered. Locations of ionospheric scintillation are estimated by triangulation using the satellites and the SCINDA ground station. Airglow images at Kwajalein are also used to confirm occurrence of equatorial ionospheric scintillations. For the selected events, large amplitude L1 and L2 scintillations tend to occur at altitudes below 200 km at frequencies around 0.5 Hz. The results are discussed as a potential path toward better specifying the occurrence of equatorial scintillations.

  9. An easy method for Ra-226 determination in river waters by liquid-scintillation counting

    NASA Astrophysics Data System (ADS)

    Moreno, H. P.; Vioque, I.; Manjón, G.; García-Tenorio, R.

    1999-01-01

    226Ra activity concentration in river water was determined using a low background liquid scintillation counter. Radium was extracted from the samples as Ra-BaSO4 precipitate which, afterwards, was dissolved with EDTA in ammonia medium. Solution was transferred into a low potassium glass vial and then mixed with a scintillation cocktail. Two different scintillation cocktails were selected for comparison. Efficiency, recovery yield and α/β separation were studied with both liquid scintillation cocktails. One single measurement, made one month after radium separation, allows to calculate the226Ra concentration as well as to assess the presence of alpha contamination of the sample. In the case of negligible interferences,224Ra concentrations can be subsequently evaluated in the same sample by the measurement made just after chemical separation of radium. This method has been applied for the determination of226Ra and224Ra activity concentrations in river water collected from different locations along the Odiel river estuary area (South-west of Spain). The presence of chemical industry, the wastes of which are released into the river, could be connected with radium activity concentration enhancements in the water.

  10. Phase and coherence analysis of VHF scintillation over Christmas Island

    NASA Astrophysics Data System (ADS)

    Shume, E. B.; Mannucci, A. J.; Caton, R.

    2014-03-01

    This short paper presents phase and coherence data from the cross-wavelet transform applied on longitudinally separated very high frequency (VHF) equatorial ionospheric scintillation observations over Christmas Island. The phase and coherence analyses were employed on a pair of scintillation observations, namely, the east-looking and west-looking VHF scintillation monitors at Christmas Island. Our analysis includes 3 years of peak season scintillation data from 2008, 2009 (low solar activity), and 2011 (moderate solar activity). In statistically significant and high spectral coherence regions of the cross-wavelet transform, scintillation observations from the east-looking monitor lead those from the west-looking monitor by about 20 to 60 (40 ± 20) min (most frequent lead times). Using several years (seasons and solar cycle) of lead (or lag) and coherence information of the cross-wavelet transform, we envisage construction of a probability model for forecasting scintillation in the nighttime equatorial ionosphere.

  11. Metal-loaded organic scintillators for neutrino physics

    NASA Astrophysics Data System (ADS)

    Buck, Christian; Yeh, Minfang

    2016-09-01

    Organic liquid scintillators are used in many neutrino physics experiments of the past and present. In particular for low energy neutrinos when realtime and energy information are required, liquid scintillators have several advantages compared to other technologies. In many cases the organic liquid needs to be loaded with metal to enhance the neutrino signal over background events. Several metal loaded scintillators of the past suffered from chemical and optical instabilities, limiting the performance of these neutrino detectors. Different ways of metal loading are described in the article with a focus on recent techniques providing metal loaded scintillators that can be used under stable conditions for many years even in ton scale experiments. Applications of metal loaded scintillators in neutrino experiments are reviewed and the performance as well as the prospects of different scintillator types are compared.

  12. Separation of scintillation and Cherenkov lights in linear alkyl benzene

    NASA Astrophysics Data System (ADS)

    Li, Mohan; Guo, Ziyi; Yeh, Minfang; Wang, Zhe; Chen, Shaomin

    2016-09-01

    To separate scintillation and Cherenkov lights in water-based liquid scintillator detectors is a desired feature for future neutrino and proton decay experiments. Linear alkyl benzene (LAB) is one important ingredient of a water-based liquid scintillator currently under development. In this paper we report on the separation of scintillation and Cherenkov lights observed in an LAB sample. The rise and decay times of the scintillation light are measured to be (7.7 ± 3.0) ns and (36.6 ± 2.4) ns , respectively, while the full width [-3σ, 3σ] of the Cherenkov light is 12 ns and is dominated by the time resolution of the photomultiplier tubes. The scintillation light yield was measured to be (1.01 ± 0.12) ×103 photons / MeV .

  13. Emulation workbench for position sensitive gaseous scintillation detectors

    NASA Astrophysics Data System (ADS)

    Pereira, L.; Margato, L. M. S.; Morozov, A.; Solovov, V.; Fraga, F. A. F.

    2015-12-01

    Position sensitive detectors based on gaseous scintillation proportional counters with Anger-type readout are being used in several research areas such as neutron detection, search for dark matter and neutrinoless double beta decay. Design and optimization of such detectors are complex and time consuming tasks. Simulations, while being a powerful tool, strongly depend on the light transfer models and demand accurate knowledge of many parameters, which are often not available. Here we describe an alternative approach based on the experimental evaluation of a detector using an isotropic point-like light source with precisely controllable light emission properties, installed on a 3D positioning system. The results obtained with the developed setup at validation conditions, when the scattered light is strongly suppressed show good agreement with simulations.

  14. Quality assurance manual plutonium liquid scintillation methods and procedures

    SciTech Connect

    Romero, L.

    1997-01-01

    Nose swipe analysis is a very important tool for Radiation Protection personnel. Nose swipe analysis is a very fast and accurate method for (1) determining if a worker has been exposed to airborne plutonium contamination and (2) Identifying the area where there has been a possible plutonium release. Liquid scintillation analysis techniques have been effectively applied to accurately determine the plutonium alpha activity on nose swipe media. Whatman-40 paper and Q-Tips are the only two media which have been evaluated and can be used for nose swipe analysis. Presently, only Q-Tips are used by Group HSE-1 Radiation Protection Personnel. However, both swipe media will be discussed in this report.

  15. The Anti-Coincidence Detector for the GLAST Large Area Telescope

    SciTech Connect

    Moiseev, A.A.; Hartman, R.C.; Ormes, J.F.; Thompson, D.J.; Amato, M.J.; Johnson, T.E.; Segal, K.N.; Sheppard, D.A.

    2007-03-23

    This paper describes the design, fabrication and testing of the Anti-Coincidence Detector (ACD) for the Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT). The ACD is LAT's first-level defense against the charged cosmic ray background that outnumbers the gamma rays by 3-5 orders of magnitude. The ACD covers the top and 4 sides of the LAT tracking detector, requiring a total active area of {approx}8.3 square meters. The ACD detector utilizes plastic scintillator tiles with wave-length shifting fiber readout. In order to suppress self-veto by shower particles at high gamma-ray energies, the ACD is segmented into 89 tiles of different sizes. The overall ACD efficiency for detection of singly charged relativistic particles entering the tracking detector from the top or sides of the LAT exceeds the required 0.9997.

  16. Flotation separation of waste plastics for recycling-A review.

    PubMed

    Wang, Chong-qing; Wang, Hui; Fu, Jian-gang; Liu, You-nian

    2015-07-01

    The sharp increase of plastic wastes results in great social and environmental pressures, and recycling, as an effective way currently available to reduce the negative impacts of plastic wastes, represents one of the most dynamic areas in the plastics industry today. Froth flotation is a promising method to solve the key problem of recycling process, namely separation of plastic mixtures. This review surveys recent literature on plastics flotation, focusing on specific features compared to ores flotation, strategies, methods and principles, flotation equipments, and current challenges. In terms of separation methods, plastics flotation is divided into gamma flotation, adsorption of reagents, surface modification and physical regulation. PMID:25869841

  17. Flotation separation of waste plastics for recycling-A review.

    PubMed

    Wang, Chong-qing; Wang, Hui; Fu, Jian-gang; Liu, You-nian

    2015-07-01

    The sharp increase of plastic wastes results in great social and environmental pressures, and recycling, as an effective way currently available to reduce the negative impacts of plastic wastes, represents one of the most dynamic areas in the plastics industry today. Froth flotation is a promising method to solve the key problem of recycling process, namely separation of plastic mixtures. This review surveys recent literature on plastics flotation, focusing on specific features compared to ores flotation, strategies, methods and principles, flotation equipments, and current challenges. In terms of separation methods, plastics flotation is divided into gamma flotation, adsorption of reagents, surface modification and physical regulation.

  18. Oxytocin and Maternal Brain Plasticity.

    PubMed

    Kim, Sohye; Strathearn, Lane

    2016-09-01

    Although dramatic postnatal changes in maternal behavior have long been noted, we are only now beginning to understand the neurobiological mechanisms that support this transition. The present paper synthesizes growing insights from both animal and human research to provide an overview of the plasticity of the mother's brain, with a particular emphasis on the oxytocin system. We examine plasticity observed within the oxytocin system and discuss how these changes mediate an array of other adaptations observed within the maternal brain. We outline factors that affect the oxytocin-mediated plasticity of the maternal brain and review evidence linking disruptions in oxytocin functions to challenges in maternal adaptation. We conclude by suggesting a strategy for intervention with mothers who may be at risk for maladjustment during this transition to motherhood, while highlighting areas where further research is needed. PMID:27589498

  19. Studies of Avalanche Photodiodes (APDS) as Readout Devices for Scintillating Fibers for High Energy Gamma-Ray Astronomy Telescopes

    NASA Technical Reports Server (NTRS)

    Vasile, Stefan; Shera, Suzanne; Shamo, Denis

    1998-01-01

    New gamma ray and charged particle telescope designs based on scintillating fiber arrays could provide low cost, high resolution, lightweight, very large area and multi radiation length instrumentation for planned NASA space exploration. The scintillating fibers low visible light output requires readout sensors with single photon detection sensitivity and low noise. The sensitivity of silicon Avalanche Photodiodes (APDS) matches well the spectral output of the scintillating fibers. Moreover, APDs have demonstrated single photon capability. The global aim of our work is to make available to NASA a novel optical detector concept to be used as scintillating fiber readouts and meeting the requirements of the new generations of space-borne gamma ray telescopes. We proposed to evaluate the feasibility of using RMD's small area APDs ((mu)APD) as scintillating fiber readouts and to study possible alternative (mu)APD array configurations for space borne readout scintillating fiber systems, requiring several hundred thousand to one million channels. The evaluation has been conducted in accordance with the task description and technical specifications detailed in the NASA solicitation "Studies of Avalanche Photodiodes (APD as readout devices for scintillating fibers for High Energy Gamma-Ray Astronomy Telescopes" (#8-W-7-ES-13672NAIS) posted on October 23, 1997. The feasibility study we propose builds on recent developments of silicon APD arrays and light concentrators advances at RMD, Inc. and on more than 5 years of expertise in scintillating fiber detectors. In a previous program we carried out the initial research to develop a high resolution, small pixel, solid-state, silicon APD array which exhibited very high sensitivity in the UV-VIS spectrum. This (mu)APD array is operated in Geiger mode and results in high gain (greater than 10(exp 8)), extremely low noise, single photon detection capability, low quiescent power (less than 10 (mu)W/pixel for 30 micrometers sensitive

  20. Lanthanide doped strontium-barium cesium halide scintillators

    SciTech Connect

    Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

    2015-06-09

    The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.