Sample records for scintillator detector setup

  1. Extruded plastic scintillation detectors

    SciTech Connect

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

    1999-04-16

    As a way to lower the cost of plastic scintillation detectors, commercially available polystyrene pellets have been used in the production of scintillating materials that can be extruded into different profiles. The selection of the raw materials is discussed. Two techniques to add wavelength shifting dopants to polystyrene pellets and to extrude plastic scintillating strips are described. Data on light yield and transmittance measurements are presented.

  2. Unitary scintillation detector and system

    DOEpatents

    McElhaney, Stephanie A. (Oak Ridge, TN); Chiles, Marion M. (Knoxville, TN)

    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.

  3. 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.

  4. A HPMT based set-up to characterize scintillating crystals

    E-print Network

    D'Ambrosio, C; Jääskeläinen, S; Lecoeur, Gérard; Leutz, H; Loos, R; Piedigrossi, D; Puertolas, D; Rosso, E; Schomaker, R

    1999-01-01

    We have developed a fully automatic measurement set-up, capable of measuring light yields arising from scintillating crystals in a linear range of about four orders of magnitude. The photodetector is a Hybrid Photomultiplier Tube especially developed to optimize linear range and photon detection. Crystal and photodetector are temperature controlled by a closed water circuit, as this is essential when measuring low light yield scintillating crystals with a marked temperature dependence of their light yield. Gamma sources can be placed either on top or on the side of the crystal. In this latter case, the source can be automatically moved by a computer-controlled step motor to provide a uniformity profile of the light yield along the crystal. Tagged and not-tagged operation modes are possible. The whole set-up is computer-controlled in an effort to provide fast and reliable measurements, to characterize many crystals per day. This is important for the quality control of the Lead Tungstate crystals that will be a...

  5. Characterization of Large Liquid Scintillation Detectors

    SciTech Connect

    Pozzi, S.A.

    2003-08-25

    This report presents the results of the characterization of 11 large liquid scintillators. The neutron energy threshold and maximum detection efficiency were determined as a function of voltage and constant fraction discriminator threshold. Fits to the response of each detector were found. The results can be used to select the experimental settings in the operation of the detectors to ensure consistent response and repeatability.

  6. Fast digitizing techniques applied to scintillation detectors

    Microsoft Academic Search

    L. Bertalot; B. Esposito; Y. Kaschuck; D. Marocco; M. Riva; A. Rizzo; D. Skopintsev

    2006-01-01

    A 200 MHz 12-bit fast transient recorder card has been used for the digitization of pulses from photomultipliers coupled to organic scintillation detectors. Two modes of operation have been developed at ENEA-Frascati: a) continuous acquisition up to a maximum duration of ˜ 1.3 s corresponding to the full on-board memory (256 MSamples) of the card: in this mode, all scintillation

  7. Large volume flow-through scintillating detector

    DOEpatents

    Gritzo, Russ E. (Los Alamos, NM); Fowler, Malcolm M. (Los Alamos, NM)

    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.

  8. Scintillation detectors of Alborz-I experiment

    NASA Astrophysics Data System (ADS)

    Pezeshkian, Yousef; Bahmanabadi, Mahmud; Abbasian Motlagh, Mehdi; Rezaie, Masume

    2015-02-01

    A new air shower experiment of the Alborz Observatory, Alborz-I, located at the Sharif University of Technology, Iran, will be constructed in near future. An area of about 30×40 m2 will be covered by 20 plastic scintillation detectors (each with an area of 50×50 cm2). A series of experiments have been performed to optimize the height of light enclosures of the detectors for this array and the results have been compared to an extended code simulation of these detectors. Operational parameters of the detector obtained by this code are cross checked by the Geant4 simulation. There is a good agreement between the extended-code and Geant4 simulations. We also present further discussions on the detector characteristics, which can be applicable for all scintillation detectors with a similar configuration.

  9. Microfluidic Scintillation Detectors for High Energy Physics

    E-print Network

    Maoddi, Pietro; Mapelli, Alessandro

    This thesis deals with the development and study of microfluidic scintillation detectors, a technology of recent introduction for the detection of high energy particles. Most of the interest for such devices comes from the use of a liquid scintillator, which entails the possibility of changing the active material in the detector, leading to increased radiation resistance. A first part of the thesis focuses on the work performed in terms of design and modelling studies of novel prototype devices, hinting to new possibilities and applications. In this framework, the simulations performed to validate selected designs and the main technological choices made in view of their fabrication are addressed. The second part of this thesis deals with the microfabrication of several prototype devices. Two different materials were studied for the manufacturing of microfluidic scintillation detectors, namely the SU-8 photosensitive epoxy and monocrystalline silicon. For what concerns the former, an original fabrication appro...

  10. Semiconductor High-Energy Radiation Scintillation Detector

    E-print Network

    Kastalsky, A; Spivak, B

    2006-01-01

    We propose a new scintillation-type detector in which high-energy radiation produces electron-hole pairs in a direct-gap semiconductor material that subsequently recombine producing infrared light to be registered by a photo-detector. The key issue is how to make the semiconductor essentially transparent to its own infrared light, so that photons generated deep inside the semiconductor could reach its surface without tangible attenuation. We discuss two ways to accomplish this, one based on doping the semiconductor with shallow impurities of one polarity type, preferably donors, the other by heterostructure bandgap engineering. The proposed semiconductor scintillator combines the best properties of currently existing radiation detectors and can be used for both simple radiation monitoring, like a Geiger counter, and for high-resolution spectrography of the high-energy radiation. The most important advantage of the proposed detector is its fast response time, about 1 ns, essentially limited only by the recombi...

  11. High resolution scintillation detector with semiconductor readout

    DOEpatents

    Levin, Craig S. (Santa Monica, CA); Hoffman, Edward J. (Los Angeles, CA)

    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.

  12. The homestake scintillation detectors: A status report

    Microsoft Academic Search

    M. L. Cherry; S. Corbato; T. Daily; D. Kieda; K. Lande; C. K. Lee

    1986-01-01

    Summary  We describe the 140 ton, 1200 m2sr Large-Area Scintillation Detector located underground at a depth of 4850 ft and the 0.8 km2 surface air shower array at the Homestake Mine. Half of the underground detector is currently operating. We discuss its performance\\u000a and describe the monopole sensitivity of the LASD and the ability of the surface-underground telescope to detect cosmic

  13. Semiconductor high-energy radiation scintillation detector

    Microsoft Academic Search

    A. Kastalsky; S. Luryi; B. Spivak

    2006-01-01

    We propose a new scintillation-type detector in which high-energy radiation generates electron–hole pairs in a direct-gap semiconductor material that subsequently recombine producing infrared light to be registered by a photo-detector. The key issue is how to make the semiconductor essentially transparent to its own infrared light, so that photons generated deep inside the semiconductor could reach its surface without tangible

  14. Comparison of Scintillating Fiber and Diamond Detector Data

    E-print Network

    McDonald, Kirk

    .77 Avalanche photodiode plastic scintillating fiber Saint-Gobain BCF-20 1/e length >3.5 meter fluorescenceComparison of Scintillating Fiber and Diamond Detector Data T. Tsang BNL (Nov 9 2009)(Nov. 9, 2009) #12;Scintillating fiber channel #0 Feb. 6, 2008 scintillating fiber 2 meter long, BCF-20, 1-mm

  15. Nanocomposite scintillator, detector, and method

    DOEpatents

    Cooke, D. Wayne (Santa Fe, NM); McKigney, Edward A. (Los Alamos, NM); Muenchausen, Ross E. (Los Alamos, NM); Bennett, Bryan L. (Los Alamos, NM)

    2009-04-28

    A compact includes a mixture of a solid binder and at least one nanopowder phosphor chosen from yttrium oxide, yttrium tantalate, barium fluoride, cesium fluoride, bismuth germanate, zinc gallate, calcium magnesium pyrosilicate, calcium molybdate, calcium chlorovanadate, barium titanium pyrophosphate, a metal tungstate, a cerium doped nanophosphor, a bismuth doped nanophosphor, a lead doped nanophosphor, a thallium doped sodium iodide, a doped cesium iodide, a rare earth doped pyrosilicate, or a lanthanide halide. The compact can be used in a radiation detector for detecting ionizing radiation.

  16. Position-sensitive scintillation detectors of nuclear radiation (Review)

    SciTech Connect

    Akimov, Yu.K. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    1995-05-01

    The techniques for detecting nuclear radiation using nontraditional light detectors, such as image converters, multichannel vacuum and solid-state photomultiplers, avalanche photodiodes, and photosensitive chambers with gas amplification are reviewed. Most of the paper is dedicated to tracking detectors with organic scintillating fibers. Devices with capillaries filled with a liquid scintillator are also considered. Position-sensitive detectors built around scintillating inorganic single crystals and glasses are described.

  17. Scintillating ribbon x-ray detector

    SciTech Connect

    Kinchen, B.E. [BK Science and Engineering, Fremont, CA (United States); Rogers, A. [Synergistic Detector Designs, Sunnyvale, CA (United States)

    1995-12-31

    A patent in the early 1970`s by Aerojet Corporation in Sacramento, CA put forth the idea of using an array of scintillating fibers for x-ray detection and imaging. In about 1975, Pratt and Whitney Aircraft in East Hartford, CT designed and manufactured an imaging system based on the patent. The device was 1.75 in thick in the direction of the x-ray beam and about 4 in. by 4 in. square. The device was used with a 8 MeV x-ray source to image and measure internal clearances within operating aircraft, gas turbines engines. There are significant advantages of fiber optic detectors in x-ray detection. However, the advantages are often outweighed by the disadvantages. Two of the advantages of scintillating fiber optic x-ray detectors are: (1) high limiting spatial frequency -- between 20 and 25 lp/mm; and (2) excellent x-ray stopping power -- they can be made thick and retain spatial resolution. In traditional fiber optic detectors the x-rays are oriented parallel to the long axis of the fiber. For the scintillating ribbon x-ray sensor, the x-rays are oriented normal to the fiber long axis. This ribbon sensor technique has a number of advantages over the two current radiographic techniques digital x-radiography and x-ray film: The main advantage the ribbon has is size and shape. It can be as thin as 0.05 in., virtually any width or length, and flexible. Once positioned in a given location, 20 to 100 square inches of the object being inspected can be imaged with a single x-ray beam sweep. It is clear that conventional digital cameras do not lend themselves to placement between walls of aircraft structures or similar items requiring x-ray inspections. A prototype scintillating ribbon x-ray sensor has been fabricated and tested by Synergistic Detector Designs. Images were acquired on corrosion test panels of aluminum fabricated by Iowa State University.

  18. 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 on the understanding of excitons. We then provide a new theoretical framework from which the nonproportionality data is reduced to a measure of the degradation in resolution. We have utilized data obtained from SLYNCI to obtain accurate nonproportionality data on several scintillators, and have developed a theory to describe the carrier dynamics to fit the data for the light yield versus electron energy.

  19. TOF-PET detector concept based on organic scintillators

    E-print Network

    Moskal, P; Bia?as, P; Ciszewska, M; Czerwi?ski, E; Heczko, A; Kajetanowicz, M; Kap?on, ?; Kochanowski, A; Konopka-Cupia?, G; Korcyl, G; Krzemie?, W; ?ojek, K; Majewski, J; Migda?, W; Molenda, M; Nied?wiecki, Sz; Pa?ka, M; Rudy, Z; Salabura, P; Silarski, M; S?omski, A; Smyrski, J; Zdebik, J; Zieli?ski, M

    2013-01-01

    In this contribution we present a new concept of the large acceptance detector systems based on organic scintillators which may allow for simultaneous diagnostic of large fraction of the human body. Novelty of the concept lies in employing large blocks of polymer scintillators instead of crystals as detectors of annihilation quanta, and in using predominantly the timing of signals instead of their amplitudes.

  20. A scintillating fission detector for neutron flux measurements

    Microsoft Academic Search

    Sy Stange; Ernst I Esch; Eric A Burgett; Iain May; Ross E Muenchausen; Felicia Taw; Fredrik K Tovesson

    2010-01-01

    Neutron flux monitors are commonly used for a variety of nuclear physics applications. A scintillating neutron detector, consisting of a liquid scintillator loaded with fissionable material, has been developed, characterized, and tested in the beam line at the Los Alamos Neutron Science Center, and shows a significant improvement in neutron sensitivity compared with a conventional fission chamber. Recent research on

  1. Bulk crystal growth of scintillator materials for gamma ray detectors

    Microsoft Academic Search

    Mohan Aggarwal

    2008-01-01

    Within the past few years, it has been demonstrated that several new rare earth halide scintillation detector crystals such as cerium doped lanthanum bromide (LaBr3:Ce) have high output and improved energy deposit to light linearity and thus they can substantially enhance the performance of the next generation of gamma ray detectors. These detectors have a variety of applications in NASA

  2. Optimizing timing performance of silicon photomultiplier-based scintillation detectors.

    PubMed

    Yeom, Jung Yeol; Vinke, Ruud; Levin, Craig S

    2013-02-21

    Precise timing resolution is crucial for applications requiring photon time-of-flight (ToF) information such as ToF positron emission tomography (PET). Silicon photomultipliers (SiPM) for PET, with their high output capacitance, are known to require custom preamplifiers to optimize timing performance. In this paper, we describe simple alternative front-end electronics based on a commercial low-noise RF preamplifier and methods that have been implemented to achieve excellent timing resolution. Two radiation detectors with L(Y)SO scintillators coupled to Hamamatsu SiPMs (MPPC S10362-33-050C) and front-end electronics based on an RF amplifier (MAR-3SM+), typically used for wireless applications that require minimal additional circuitry, have been fabricated. These detectors were used to detect annihilation photons from a Ge-68 source and the output signals were subsequently digitized by a high speed oscilloscope for offline processing. A coincident resolving time (CRT) of 147 ± 3 ps FWHM and 186 ± 3 ps FWHM with 3 × 3 × 5 mm(3) and with 3 × 3 × 20 mm(3) LYSO crystal elements were measured, respectively. With smaller 2 × 2 × 3 mm(3) LSO crystals, a CRT of 125 ± 2 ps FWHM was achieved with slight improvement to 121 ± 3 ps at a lower temperature (15° C). Finally, with the 20 mm length crystals, a degradation of timing resolution was observed for annihilation photon interactions that occur close to the photosensor compared to shallow depth-of-interaction (DOI). We conclude that commercial RF amplifiers optimized for noise, besides their ease of use, can produce excellent timing resolution comparable to best reported values acquired with custom readout electronics. On the other hand, as timing performance degrades with increasing photon DOI, a head-on detector configuration will produce better CRT than a side-irradiated setup for longer crystals. PMID:23369872

  3. Optimizing timing performance of silicon photomultiplier-based scintillation detectors

    NASA Astrophysics Data System (ADS)

    Yeom, Jung Yeol; Vinke, Ruud; Levin, Craig S.

    2013-02-01

    Precise timing resolution is crucial for applications requiring photon time-of-flight (ToF) information such as ToF positron emission tomography (PET). Silicon photomultipliers (SiPM) for PET, with their high output capacitance, are known to require custom preamplifiers to optimize timing performance. In this paper, we describe simple alternative front-end electronics based on a commercial low-noise RF preamplifier and methods that have been implemented to achieve excellent timing resolution. Two radiation detectors with L(Y)SO scintillators coupled to Hamamatsu SiPMs (MPPC S10362-33-050C) and front-end electronics based on an RF amplifier (MAR-3SM+), typically used for wireless applications that require minimal additional circuitry, have been fabricated. These detectors were used to detect annihilation photons from a Ge-68 source and the output signals were subsequently digitized by a high speed oscilloscope for offline processing. A coincident resolving time (CRT) of 147 ± 3 ps FWHM and 186 ± 3 ps FWHM with 3 × 3 × 5 mm3 and with 3 × 3 × 20 mm3 LYSO crystal elements were measured, respectively. With smaller 2 × 2 × 3 mm3 LSO crystals, a CRT of 125 ± 2 ps FWHM was achieved with slight improvement to 121 ± 3 ps at a lower temperature (15° C). Finally, with the 20 mm length crystals, a degradation of timing resolution was observed for annihilation photon interactions that occur close to the photosensor compared to shallow depth-of-interaction (DOI). We conclude that commercial RF amplifiers optimized for noise, besides their ease of use, can produce excellent timing resolution comparable to best reported values acquired with custom readout electronics. On the other hand, as timing performance degrades with increasing photon DOI, a head-on detector configuration will produce better CRT than a side-irradiated setup for longer crystals.

  4. Retroreflector arrays for better light collection efficiency of ?-ray imaging detectors with continuous scintillation crystals without DOI misestimation

    NASA Astrophysics Data System (ADS)

    Ros, A.; Lerche, Ch W.; Sebastia, A.; Sanchez, F.; Benlloch, J. M.

    2014-04-01

    A method to improve light collection efficiency of ?-ray imaging detectors by using retroreflector arrays has been tested, simulations of the behaviour of the scintillation light illuminating the retroreflector surface have been made. Measurements including retroreflector arrays in the setup have also been taken. For the measurements, positron emission tomography (PET) detectors with continuous scintillation crystals have been used. Each detector module consists of a continuous LSO-scintillator of dimensions 49x49x10 mm3 and a H8500 position-sensitive photo-multiplier (PSPMT) from Hamamatsu. By using a continuous scintillation crystal, the scintillation light distribution has not been destroyed and the energy, the centroids along the x- and y-direction and the depth of interaction (DOI) can be estimated. Simulations have also been run taking into account the use of continuous scintillation crystals. Due to the geometry of the continuous scintillation crystals in comparison with pixelated crystals, a good light collection efficiency is necessary to correctly reconstruct the impact point of the ?-ray. The aim of this study is to investigate whether micro-machine retro-reflectors improve light yield without misestimation of the impact point. The results shows an improvement on the energy and centroid resolutions without worsening the depth of interaction resolution. Therefore it can be concluded that using retroreflector arrays at the entrance side of the scintillation crystal improves light collection efficiency without worsening the impact point estimation.

  5. The lower bound on the timing resolution of scintillation detectors.

    PubMed

    Seifert, Stefan; van Dam, Herman T; Schaart, Dennis R

    2012-04-01

    The timing performance of scintillation detectors is ultimately limited by photon counting statistics. In fact, photon counting statistics form a dominant contribution to the overall timing resolution of many state-of-the-art detectors. A common approach to investigate this contribution is to calculate the variance in the registration times of individual scintillation photons within the photosensor. However, in general the single-photon variance is not equal to the intrinsic limit on the timing resolution, since in principle one can make use of the timing information carried by all photons detected. In this work, the Cramér-Rao lower bound on the timing resolution of a scintillation detector, based on the information contained in the full set of registered photons, is calculated. The results appear to be in good agreement with trends observed in the literature. Furthermore, it is shown that the timestamp obtained from any single scintillation photon never yields the optimum timing resolution for realistic scintillation detectors. Yet, it appears that the intrinsic timing resolution limit can be approached closely by making use of the timestamps from a relatively small number of photons emitted during the initial part of the scintillation pulse. PMID:22410975

  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. Setup optimization toward accurate ageing studies of gas filled detectors

    NASA Astrophysics Data System (ADS)

    Abuhoza, A.; Schmidt, H. R.; Biswas, S.; Frankenfeld, U.; Hehner, J.; Schmidt, C. J.

    2013-08-01

    An infrastructure has been set up at the GSI detector laboratory to study the influence of construction materials on the ageing properties of gas filled detectors, such as multi-wire proportional chamber (MWPC), gas electron multiplier (GEM). Optimization of an ageing setup was performed by observing the variation of the normalized gain obtained using two identical MWPCs. An accuracy in the relative gain measurement below 1% has been achieved by monitoring environmental conditions and by systematic improvements of the measuring equipment. Ageing test of fiberglass G11 has been performed.

  8. Light collection in scintillation detector composites for neutron detection

    Microsoft Academic Search

    G. F. Knoll; T. F. Knoll; T. M. Henderson

    1988-01-01

    With the goal of developing neutron detectors of high detection efficiency and fast response, the authors have been investigating the heterogeneous combination of neutron-conversion materials in a plastic or liquid scintillation matrix. One such combination consists of thin-wall glass microspheres filled with high pressure ³He gas dispersed in plastic scintillator. The authors have now developed glass formulations that are capable

  9. 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.

  10. Performance of photomultiplier tubes and sodium iodide scintillation detector systems

    NASA Technical Reports Server (NTRS)

    Meegan, C. A.

    1981-01-01

    The performance of photomultiplier tubes (PMT's) and scintillation detector systems incorporating 50.8 by 1.27 cm NaI (T l) crystals was investigated to determine the characteristics of the photomultiplier tubes and optimize the detector geometry for the Burst and Transient Source Experiment on the Gamma Ray Observatory. Background information on performance characteristics of PMT's and NaI (T l) detectors is provided, procedures for measurement of relevant parameters are specified, and results of these measurements are presented.

  11. 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.

  12. Homestake Large Area Scintillation Detector and cosmic ray telescope

    SciTech Connect

    Cherry, M.L.; Corbato, S.; Kieda, D.; Lande, K.; Lee, C.K.; Steinberg, R.I.

    1985-01-25

    The Homestake Large Area Scintillation Detector consists of 140 tons of liquid scintillator in a hollow 8 m x 8 m x 16 m box surrounding the Brookhaven /sup 37/Cl solar neutrino detector. The experiment is located at a depth of 4850 ft. (4200 m.w.e.) in the Homestake Gold Mine. Half of the detector is currently running; the full detector will be taking data early in 1985. An extensive air shower array is also currently under construction on the earth's surface above the underground chamber, consisting of 100 scintillators, each 3 m/sup 2/, covering approximately 0.8 km/sup 2/; the first portion of the surface array will also be providing data in early 1985. Together, the new Homestake detectors (Fig. 1) will be used to search for slow, massive magnetic monopoles; study the zenith angle distribution of neutrino-induced muons; search for neutrino bursts from the gravitational collapse of massive stars; measure the multiplicity and transverse momentum distributions of cosmic ray muons; and study the composition of the primary cosmic rays. In this paper, we present a progress report on the new detectors. In Sec. I we describe the underground device and its capabilities as a monopole detector; in Sec. II we describe the surface array and the cosmic ray studies; the neutrino measurements have been discussed elsewhere.

  13. Towards an understanding of nonlinearity in scintillator detector materials

    NASA Astrophysics Data System (ADS)

    Bizarri, G.; Moses, W. W.; Payne, S. A.; Williams, R. T.

    2011-09-01

    It has been known for more than 50 years that the light emitted by a scintillator under high-energy excitation (gamma, alpha, proton) is not always proportional to the amount of absorbed energy. The deviation from the linearity of luminosity versus absorbed energy is known as nonproportionality. In addition to its academic interest, this phenomenon has been considered central for scintillator development due to its implication in the limitation of achievable detector performance. Although non-proportional response was studied intensively during the second part of the 20th century, the understanding of its origin and implications on scintillator performance are mainly qualitative. Research in the 1960s uncovered a correlation between proportional response and ionization density, while in the 1980s nonproportionality was proposed as the main reason of energy resolution deviation from the counting statistics limit. It is only recently that the bridge between qualitative and quantitative understanding has been crossed, mainly driven by the large effort undertaken to discover new high-resolution scintillators. Developing such detector materials prompted efforts to gain a deeper understanding of the microscopic processes involved in scintillation mechanisms and so in nonproportionality. In this manuscript, the phenomenology of past and present understanding of non-proportional response will be reviewed. Based on recent experimental, computational and theoretical works, the relation between nonlinear response and energy resolution degradation will be addressed. Finally, the relation between material parameters and proportionality will be evaluated. These recent works are leading towards a deeper understanding of nonlinearity in scintillator detector materials and should result in the development of new high performance scintillator materials.

  14. Combined composite scintillation detector for separate measurements of fast and thermal neutrons

    Microsoft Academic Search

    Nikolai Z. Galunov; Boris V. Grinyov; Natalya L. Karavaeva; Eugenia V. Martynenko; Oleg A. Tarasenko; Yaroslav V. Gerasymov; Oleg Ts. Sidletskiy

    2010-01-01

    We propose and study a new composite scintillation detector. It is the combined detector for separate detection of fast neutrons and thermal neutrons in the presence of gamma background radiation. The combined detector consists of two scintillation parts. It is the organic composite scintillator that is made from stilbene crystalline grains (grains with sizes from 2.5 to 3.0 mm) those

  15. Comparisons of Scintillating Fiber, Diamond Particle Detector

    E-print Network

    McDonald, Kirk

    _AB_note.pdf guard ring electrode #12;Response of diamond particle detector using injection 241Am @ 5.5 MeV 241Am detector using 193 nm ArF laser laser illumination location #12;Response of diamond particle detector using

  16. Design of organic scintillators for non-standard radiation field dosimetry: experimental setup.

    PubMed

    Norman H, Machado R; Maximiliano, Trujillo T; Javier E, García G; Diana C, Narvaez G; Paula A, Marín M; Róbinson A, Torres V

    2013-01-01

    This paper describes an experimental setup designed for sensing the luminescent light coming from an organic plastic scintillator stimulated with ionizing radiation. This device is intended to be a part of a complete dosimeter system for characterization of small radiation fields which is the project of the doctoral thesis of the medical physicist at the Radiation Oncology facility of Hospital San Vicente Fundación in conjunction with the Universidad de Antioquia of Medellín Colombia. Some preliminary results predict a good performance of the unit, but further studies must be conducted in order to have a completed evaluation of the system. This is the first step in the development of an accuracy tool for measurement of non-standard fields in the Radiotherapy or Radiosurgery processes. PMID:24110369

  17. A scintillating fission detector for neutron flux measurements

    SciTech Connect

    Stange, Sy [Los Alamos National Laboratory; Esch, Ernst I [Los Alamos National Laboratory; Burgett, Eric A [Los Alamos National Laboratory; May, Iain [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Taw, Felicia [Los Alamos National Laboratory; Tovesson, Fredrik K [Los Alamos National Laboratory

    2010-01-01

    Neutron flux monitors are commonly used for a variety of nuclear physics applications. A scintillating neutron detector, consisting of a liquid scintillator loaded with fissionable material, has been developed, characterized, and tested in the beam line at the Los Alamos Neutron Science Center, and shows a significant improvement in neutron sensitivity compared with a conventional fission chamber. Recent research on nanocomposite-based scintillators for gamma-ray detection indicates that this approach can be extended to load nanoparticles of fissionable material into a scintillating matrix, with up to three orders of magnitude higher loading than typical fission chambers. This will result in a rugged, cost-efficient detector with high efficiency, a short signal rise time, and the ability to be used in low neutron-flux environments. Initial efforts to utilize the luminescence of uranyl oxide to eliminate the need for wavelength-shifting dyes were unsuccessful. Excitation of uranyl compounds has been reported at wavelengths ranging from 266 nm to 532 nm. However, neither the 300 nm emission of toluene, nor the 350 nm emission of PPO, nor the 410 nm emission of POPOP resulted in significant excitation of and emission by uranyl oxide. As indicated by UV/visible spectroscopy, light emitted at these wavelengths was absorbed by the colored solution. {sup 235}U remains the most attractive candidate for a fissionable scintillator, due to its high fission cross-section and lack of a threshold fission energy, but all solutions containing molecular uranium compounds will be colored, most more highly than the U{sup 6+} compounds used here. Research is therefore continuing toward the fabrication of uranium nanoparticles, in which, due to Rayleigh scattering, the coloration should be less pronounced. The characterization of the thorium-loaded liquid scintillator and the fabrication of the 100 mL detectors for use at LANSCE demonstrated the feasibility of loading fissionable material into a liquid scintillator. Analysis of beam line experiments using the thorium-loaded scintillator is underway to determine the fission event rate in the detector, for comparison with a conventional fission chamber as well as with an unloaded liquid scintillator.

  18. Active Inspection of Nuclear Materials Using 4He Scintillation Detectors

    NASA Astrophysics Data System (ADS)

    Davatz, G.; Chandra, R.; Gendotti, U.; Howard, A.

    2011-12-01

    The detection of fissionable materials by neutron and high-energy photon active interrogation methods is explored using 4He scintillation detectors to search for prompt and delayed neutron signature. The low electron density of 4He in addition to its pulse shape discrimination capability allows strong rejection of gamma radiation. For the detection of the prompt neutron signatures, this capability is important as the signal produced by induced fission is accompanied by intense gamma radiation. The nanosecond time resolution of 4He scintillation detectors can be used for time-of-flight measurements aimed at determining the energy of the emitted neutrons. For delayed neutron detection, the insensitivity to the low energy neutrons present from non-signal reactions is inherent. Unlike detectors requiring a moderator, this technology can easily be collimated to reduce sensitivity to neutrons from outside the field of interest. The performance of the detectors for these applications is studied using GEANT4 computer modeling, based on measured detector parameters. A comparison is made with technologies typically used for these applications, i.e. heavily shielded organic scintillators for prompt neutron detection and Cd-lined 3He neutron detectors for the detection of delayed neutrons.

  19. Monte Carlo simulation of the data acquisition chain of scintillation detectors

    SciTech Connect

    Binda, F.; Ericsson, G.; Hellesen, C.; Hjalmarsson, A.; Eriksson, J.; Skiba, M.; Conroy, S.; Weiszflog, M. [Uppsala University, Department of Physics and Astronomy, Division of Applied Nuclear Physics, 75120 Uppsala (Sweden)

    2014-08-21

    The good performance of a detector can be strongly affected by the instrumentation used to acquire the data. The possibility of anticipating how the acquisition chain will affect the signal can help in finding the best solution among different set-ups. In this work we developed a Monte Carlo code that aims to simulate the effect of the various components of a digital Data Acquisition system (DAQ) applied to scintillation detectors. The components included in the model are: the scintillator, the photomultiplier tube (PMT), the signal cable and the digitizer. We benchmarked the code against real data acquired with a NE213 scintillator, comparing simulated and real signal pulses induced by gamma-ray interaction. Then we studied the dependence of the energy resolution of a pulse height spectrum (PHS) on the sampling frequency and the bit resolution of the digitizer. We found that exceeding some values of the sampling frequency and the bit resolution improves only marginally the performance of the system. The method can be applied for the study of various detector systems relevant for nuclear techniques, such as in fusion diagnostics.

  20. Fiber optic thermal/fast neutron and gamma ray scintillation detector

    DOEpatents

    Neal, John S.; Mihalczo, John T.

    2006-11-28

    A detector system that combines a .sup.6Li loaded glass fiber scintillation thermal neutron detector with a fast scintillation detector in a single layered structure. Detection of thermal and fast neutrons and ionizing electromagnetic radiation is achieved in the unified detector structure. The fast scintillator replaces the polyethelene moderator layer adjacent the .sup.6Li loaded glass fiber panel of the neutron detector and acts as the moderator for the glass fibers. Fast neutrons, x-rays and gamma rays are detected in the fast scintillator. Thermal neutrons, x-rays and gamma rays are detected in the glass fiber scintillator.

  1. Bulk crystal growth of scintillator materials for gamma ray detectors

    NASA Astrophysics Data System (ADS)

    Aggarwal, Mohan

    2008-10-01

    Within the past few years, it has been demonstrated that several new rare earth halide scintillation detector crystals such as cerium doped lanthanum bromide (LaBr3:Ce) have high output and improved energy deposit to light linearity and thus they can substantially enhance the performance of the next generation of gamma ray detectors. These detectors have a variety of applications in NASA hard x-ray and gamma ray missions, high energy physics, home land security and medical imaging applications. This cerium doped lanthanum bromide crystal has ˜1100% the light output of BGO, resulting in better energy resolution than conventional scintillators. This is equivalent to 60000 photons per MeV of deposited energy. This new series of scintillator materials promise to usher a breakthrough in the field, if sufficiently large and clear crystals of this material can be grown. These halides however are highly hygroscopic and hence pose some difficulty in growing crystals. Efforts are being made to grow this and other materials in this family of crystals and successful results have been achieved. An overview of the challenges encountered during the synthesis and melt crystal growth of these rare earth halide scintillators shall be presented.

  2. Neutrino Flavor Sensitivity of Large Liquid Scintillator Detectors

    NASA Astrophysics Data System (ADS)

    Loo, K. K.; Bick, D.; Enqvist, T.; Hellgartner, D.; Kaiser, M.; Lorenz, S.; Meloni, M.; Meyer, M.; Möllenberg, R.; Oberauer, L.; Soiron, M.; Smirnov, M.; Stahl, A.; Trzaska, W. H.; Wonsak, B.; Wurm, M.

    Scintillator detectors are known for their good light yield, energy resolution, timing characteristics and pulse shape discrimination capabilities. These features make the next-generation liquid scintillation detector LENA[1] (Low Energy Neutrino Astronomy) the optimal choice for a wide range of astro-particle topics including supernova-, solar-, and geo neutrinos. In addition to the excellent calorimetric and timing properties, scintillartor detectors (LSDs) are also capable of topology reconstruction sufficient to discriminate with adequate efficiency between electron and muon neutrino induced charge current events and neutral current events in the GeV energy range. This feature makes LENA a competitive tool for the determination of the mass hierarchy (MH) with long baseline neutrino beams such as the proposed CN2PY beam (2288 km). This work summarizes the status of the current work on track reconstruction schemes and discusses the sensitivity limit for the neutrino mass hierarchy measurement with LENA.

  3. Position Reconstruction in a Dual Phase Xenon Scintillation Detector

    NASA Astrophysics Data System (ADS)

    Solovov, V. N.; Belov, V. A.; Akimov, D. Yu.; Araujo, H. M.; Barnes, E. J.; Burenkov, A. A.; Chepel, V.; Currie, A.; DeViveiros, L.; Edwards, B.; Ghag, C.; Hollingsworth, A.; Horn, M.; Kalmus, G. E.; Kobyakin, A. S.; Kovalenko, A. G.; Lebedenko, V. N.; Lindote, A.; Lopes, M. I.; Luscher, R.; Majewski, P.; Murphy, A. S. J.; Neves, F.; Paling, S. M.; Pinto da Cunha, J.; Preece, R.; Quenby, J. J.; Reichhart, L.; Scovell, P. R.; Silva, C.; Smith, N. J. T.; Smith, P. F.; Stekhanov, V. N.; Sumner, T. J.; Thorne, C.; Walker, R. J.

    2012-12-01

    We studied the application of statistical reconstruction algorithms, namely maximum likelihood and least squares methods, to the problem of event reconstruction in a dual phase liquid xenon detector. An iterative method was developed for in-situ reconstruction of the PMT light response functions from calibration data taken with an uncollimated gamma-ray source. Using the techniques described, the performance of the ZEPLIN-III dark matter detector was studied for 122 keV gamma-rays. For the inner part of the detector (R<100 mm), spatial resolutions of 13 mm and 1.6 mm FWHM were measured in the horizontal plane for primary and secondary scintillation, respectively. An energy resolution of 8.1% FWHM was achieved at that energy. The possibility of using this technique for improving performance and reducing cost of scintillation cameras for medical applications is currently under study.

  4. Photoelectron anticorrelations and sub-Poisson statistics in scintillation detectors

    PubMed Central

    Bousselham, Abdelkader; Barrett, Harrison H.; Bora, Vaibhav; Shah, Kanai

    2010-01-01

    The performance of scintillation detectors for x rays and gamma rays is limited fundamentally by the statistics of the scintillation light and the resulting photoelectrons. This paper presents a new experimental approach to studying these statistics by observing correlations in the signals from two photodetectors. It is shown that the Fano factors (ratios of variance to mean), both for the number the photoelectrons produced on the photocathode of the photomultiplier and for the underlying number of scintillation photons, can be deduced from these correlations. For LaBr3(Ce) and 662 keV gamma rays, the photopeak signals obtained by photomultipliers on opposite faces of a thin sample are negatively correlated, and the Fano factor for the photoelectrons is significantly less than one. The inferred Fano factor for the optical photons is very small, indistinguishable from zero within experimental error. PMID:20725609

  5. Characterizing the response of miniature scintillation detectors when irradiated with proton beams

    Microsoft Academic Search

    Louis Archambault; Jerimy C Polf; Luc Beaulieu; Sam Beddar

    2008-01-01

    Designing a plastic scintillation detector for proton radiation therapy requires careful consideration. Most of the plastic scintillators should not perturb a proton beam if they are sufficiently small but may exhibit some energy dependence due to the quenching effect. In this work, we studied the factors that would affect the performance of such scintillation detectors. We performed Monte Carlo simulations

  6. High Count Rate Neutron Spectrometry With Liquid Scintillation Detectors

    Microsoft Academic Search

    Daniele Marocco; Francesco Belli; Basilio Esposito; Marco Riva; Luca Giacomelli; Marcel Reginatto; Kai Tittelmeier; Andreas Zimbal

    2009-01-01

    Liquid scintillation detectors are widely used in nuclear\\/high-energy physics and nuclear fusion for spectral measurements in mixed radiation fields due to their compactness, fast response and neutron\\/gamma discrimination capabilities. The use of response functions evaluated for the specific system and of appropriate methods of data analysis allows such systems to be used as broadband spectrometers for photons and neutrons. System

  7. Optical scattering lengths in large liquid-scintillator neutrino detectors.

    PubMed

    Wurm, M; von Feilitzsch, F; Göger-Neff, M; Hofmann, M; Lachenmaier, T; Lewke, T; Marrodán Undagoitia, T; Meindl, Q; Möllenberg, R; Oberauer, L; Potzel, W; Tippmann, M; Todor, S; Traunsteiner, C; Winter, J

    2010-05-01

    For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents phenylxylylethane, linear alkylbenzene (LAB), and dodecane, which are under discussion for next-generation experiments such as SNO+ (Sudbury Neutrino Observatory), HanoHano, or LENA (Low Energy Neutrino Astronomy). Results comprise the wavelength range of 415-440 nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector. PMID:20515130

  8. Scintillating fiber near detector for the Neutrino Factory

    E-print Network

    Rosen Matev

    2011-10-10

    Neutrino Factory is a facility for future precision studies of neutrino oscillations. A so called near detector is essential for reaching the aimed precision of neutrino oscillation analysis. Main task of a near detector is to measure the flux of the neutrino beam. The brilliant neutrino source provides opportunity for precision studies of various neutrino interaction processes in a near detector. We present design concept of a scintillating fiber tracker capable of measuring the neutrino flux. The basic idea is to separate pure leptonic neutrino-electron scattering from the overwhelming background of neutrino-nucleon interactions. Monte Carlo simulation of the detector and simple event reconstruction algorithms are presented. It is shown that proper selection cuts increase signal to background ratio from ~ 10^{-4} to 30-50 %. Two methods for extraction of signal events are developed.

  9. High quantum efficiency megavoltage imaging with thick scintillator detectors for image guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Gopal, Arun

    In image guided radiation therapy (IGRT), imaging devices serve as guidance systems to aid patient set-up and tumor volume localization. Traditionally, 2-D megavoltage x-ray imagers, referred to as electronic portal imaging devices (EPIDs), have been used for planar target localization, and have recently been extended to perform 3-D volumetric reconstruction via cone-beam computed tomography (CBCT). However, current EPIDs utilize thin and inefficient phosphor screen detectors and are subsequently limited by poor soft tissue visualization, which limits their use for CBCT. Therefore, the use of thick scintillation media as megavoltage x-ray detectors for greater x-ray sensitivity and enhanced image quality has recently been of significant interest. In this research, two candidates for thick scintillators: CsI(Tl) and terbium doped scintillation glass were investigated in separate imaging configurations. In the first configuration, a thick scintillation crystal (TSC) consisting of a thick, monolithic slab of CsI(Tl) was coupled to a mirror-lens-camera system. The second configuration is based on a fiber-optic scintillation glass array (FOSGA), wherein the scintillation glass is drawn into long fiber-optic conduits, inserted into a grid-type housing constructed out of polymer-tungsten alloy, and coupled to an array of photodiodes for digital read-out. The imaging prototypes were characterized using theoretical studies and imaging measurements to obtain fundamental metrics of imaging performance. Spatial resolution was measured based on a modulation transfer function (MTF), noise was evaluated in terms of a noise power spectrum (NPS), and overall contrast was characterized in the form of detective quantum efficiency (DQE). The imaging studies were used to optimize the TSC and FOSGA imagers and propose prototype configurations for order-of-magnitude improvements in overall image quality. In addition, a fast and simple technique was developed to measure the MTF, NPS, and DQE metrics for clinical EPID and CBCT systems based on a novel adaptation of a traditional line-pair resolution bar-pattern. This research provides two significant benefits to radiotherapy: the characterization of a new generation of thick scintillator based megavoltage x-ray imagers for CBCT based IGRT, and the novel adaptation of fundamental imaging metrics from imaging research to routine clinical performance monitoring.

  10. Comparison of gamma-ray detectors: Scintillators, scintillating fibers, and semiconductors

    SciTech Connect

    Moss, C.E. [Los Alamos National Lab., CA (United States)

    1994-12-31

    New scintillators that have advantages relative to NaI(Tl) and BGO include GSO, LSO, YAP, and BaF{sub 2}. GSO, for example, is very radiation hard, and BaF{sub 2} is very fast. Scintillating fibers, which allow good spatial resolution and complex geometries, have been used extensively in high energy physics, but they can also be used at lower energies. Semiconductors such as germanium, silicon, CdTe, CdZnTe, and HgI{sub 2} can provide good resolution. The proliferation of types has made selection of a gamma-ray detector for a particular application difficult. The authors compare the different types and give examples of choices that have been made for laboratory experiments, portable instruments, and space applications.

  11. Time-based position estimation in monolithic scintillator detectors.

    PubMed

    Tabacchini, Valerio; Borghi, Giacomo; Schaart, Dennis R

    2015-07-21

    Gamma-ray detectors based on bright monolithic scintillation crystals coupled to pixelated photodetectors are currently being considered for several applications in the medical imaging field. In a typical monolithic detector, both the light intensity and the time of arrival of the earliest scintillation photons can be recorded by each of the photosensor pixels every time a gamma interaction occurs. Generally, the time stamps are used to determine the gamma interaction time while the light intensities are used to estimate the 3D position of the interaction point. In this work we show that the spatio-temporal distribution of the time stamps also carries information on the location of the gamma interaction point and thus the time stamps can be used as explanatory variables for position estimation. We present a model for the spatial resolution obtainable when the interaction position is estimated using exclusively the time stamp of the first photon detected on each of the photosensor pixels. The model is shown to be in agreement with experimental measurements on a 16?mm??×??16?mm??×??10?mm LSO?:?Ce,0.2%Ca crystal coupled to a digital photon counter (DPC) array where a spatial resolution of 3?mm (root mean squared error) is obtained. Finally we discuss the effects of the main parameters such as scintillator rise and decay time, light output and photosensor single photon time resolution and pixel size. PMID:26133784

  12. Scintillator and solid-state neutron detectors and their applications

    NASA Astrophysics Data System (ADS)

    Carturan, Sara Maria; Marchi, Tommaso; Fanchini, Erica; De Vita, Raffaella; Finocchiaro, Paolo; Pappalardo, Alfio

    2014-10-01

    The application range of neutron detectors covers many topics, not only involving experimental research, but spanning tens of industrial, health, transport, cultural heritage fields of interest. Several studies focus on new scintillating materials where the light response, under fast and slow neutrons exposure, is triggered by proton recoil or by the presence of neutron capture materials as 10B, 6Li or 157Gd. Neutron monitors, where the robustness of silicon-based detectors can be fully exploited by coupling with suitable neutron absorber/converter materials, have recently proved their outstanding performances. Discrimination between neutron signals from other radiations, such as - or cosmic rays, is achieved through timing techniques or with pulse shape analysis. Furthermore, the choice of the detection/discrimination techniques depends on the type of application the detector will be used for. An example is Radiation Portal Monitors (RPM) for cargo inspection or luggage control that are required to satisfy specific international standards for and neutron detection efficiencies. This paper is an overview of some of the National Institute of Nuclear Physics (INFN) activities in the field of neutron detection, involving novel technologies. We will describe the most recent advances related to scintillators and silicon-based detectors coupled with thin films of suitable converters for neutron detection and we will discuss applications in the field of nuclear security.

  13. Apparatus and method for temperature correction and expanded count rate of inorganic scintillation detectors

    DOEpatents

    Ianakiev, Kiril D. (Los Alamos, NM); Hsue, Sin Tao (Santa Fe, NM); Browne, Michael C. (Los Alamos, NM); Audia, Jeffrey M. (Abiquiu, NM)

    2006-07-25

    The present invention includes an apparatus and corresponding method for temperature correction and count rate expansion of inorganic scintillation detectors. A temperature sensor is attached to an inorganic scintillation detector. The inorganic scintillation detector, due to interaction with incident radiation, creates light pulse signals. A photoreceiver processes the light pulse signals to current signals. Temperature correction circuitry that uses a fast light component signal, a slow light component signal, and the temperature signal from the temperature sensor to corrected an inorganic scintillation detector signal output and expanded the count rate.

  14. A scintillating fibres tracker detector for archaeological applications

    NASA Astrophysics Data System (ADS)

    Menichelli, M.; Ansoldi, S.; Bari, M.; Basset, M.; Battiston, R.; Blasko, S.; Coren, F.; Fiori, E.; Giannini, G.; Iugovaz, D.; Papi, A.; Reia, S.; Scian, G.

    2007-03-01

    We designed, constructed and operated a cylindrical, scintillating fibres, tracker detector in order to measure the directional flux of cosmic ray muons underground. This instrument named Muon Ground Radiograph (MGR) was developed to study the fluctuation of the density in the soil that causes detection anisotropies in the arrival direction of cosmic ray muons observed in a tracker detector located underground. Density fluctuations may reveal hidden cavities or buried structures and can contribute to archaeological findings. The shape of the detector we used, for this purpose, is cylindrical, 14 cm diameter and 224 cm height, and it can be inserted into a 20 cm diameter hole in the ground at a maximum depth of 30 m. This paper will describe the instrument design and construction and also report some results of two observational campaigns in the town of Aquileia the Claudio and Traiano port.

  15. Modeling of the pressurized xenon gamma ray scintillation detector

    NASA Astrophysics Data System (ADS)

    Meek, Romney; Barzilov, Alexander; Novikov, Ivan

    2011-10-01

    We are developing a high pressure xenon detector for photon measurements. Xenon produces electroluminescence (EL) scintillation emission that we use as the primary signal in our strategy to acquire information. The detector consists of a high pressure chamber, a thin radiation input window with the supporting grid of collimator ribs and electrode grids to create the electric field, and a photo sensor -- the large area silicon avalanche photodiode. The electrode grids are made of thin wire. The modeling of the electric field is a crucial step in developing a working prototype. It has been previously shown that the uniform electric field divided by the number density of xenon gas needs to be above approximately 3 Td to give enough energy to ionize the xenon atoms, but less than 16 Td to prevent electron avalanches from occurring. The electric field was modeled using Comsol Multiphysics. This presentation discusses the results of electric field modeling for the detector (absorption, drift, and EL regions).

  16. Comparison of LuYAP, LSO, and BGO as scintillators for high resolution PET detectors

    Microsoft Academic Search

    Simone Weber; Daniela Christ; Marcel Kurzeja; Ralf Engels; Guenter Kemmerling; Horst Halling

    2003-01-01

    For high resolution positron emission tomographs based on scintillation detectors a fast, dense, and bright scintillator is required. A sample of a new scintillator, Lu0.8Y0.2AlO3:Ce (LuYAP) with a density of 7.7 g\\/cm3 and a scintillation decay time of 20 and 160 ns is compared with LSO and BGO crystals of the same size to estimate the potential of the crystal

  17. Warhead counting using neutron scintillators: Detector development, testing, and demonstration

    NASA Astrophysics Data System (ADS)

    Byrd, R. C.; Auchampaugh, G. F.; Moss, C. E.; Feldman, W. C.

    1991-11-01

    Although the number of warheads on a missile can be determined relatively simply by a scan of the emitted gamma radiation, this approach may be considered too intrusive because of the possibility of revealing high resolution energy or position information. Neutron spectra are nearly featureless, and obtaining the position resolution needed to reveal warhead details would be very difficult. We describe the development of a fast neutron detector based on a boron-loaded plastic scintillator used previously for space applications. The detector rejects gammas and scattered low energy neutrons, and its segmentation allows narrow fan-shaped collimation within + or - 20 degs horizontally and + or - 50 degs vertically. Testing includes distinguishing between mockups with either two or three warheads and locating the ten warheads on a silo-based Peacekeeper missile.

  18. Performance characterization of a new high resolution PET scintillation detector

    PubMed Central

    Foudray, A M K; Olcott, P D

    2013-01-01

    Performance of a new high resolution PET detection concept is presented. In this new concept, annihilation radiation enters the scintillator detectors edge-on. Each detector module comprises two 8 × 8 LYSO scintillator arrays of 0.91 × 0.91 × 1 mm3 crystals coupled to two position-sensitive avalanche photodiodes (PSAPDs) mounted on a flex circuit. Appropriate crystal segmentation allows the recording of all three spatial coordinates of the interaction(s) simultaneously with submillimeter resolution. We report an average energy resolution of 14.6 ± 1.7% for 511 keV photons at FWHM. Coincident time resolution was determined to be 2.98 ± 0.13 ns FWHM on average. The coincidence point spread function (PSF) has an average FWHM of 0.837 ± 0.049 mm (using a 500 ?m spherical source) and is uniform across the arrays. Both PSF and coincident time resolution degrade when Compton interactions are included in the data. Different blurring factors were evaluated theoretically, resulting in a calculated PSF of 0.793 mm, in good agreement with the measured value. PMID:20844332

  19. Contamination monitors for nuclear power plants; Plastic scintillators vs. proportional detectors

    Microsoft Academic Search

    E. Geiger; L. Phyfe; W. Fisher

    1985-01-01

    This paper reports on trends in monitoring for radioactive material (contamination) on or in waste, tools, laundry and personnel at nuclear power stations which have been towards the increased use of large-area gas-flow proportional detectors and large plastic scintillators. Solid plastic scintillators can be made sensitive primarily to beta, gamma only, or both beta and gamma radiation. Proportional detectors can

  20. Cascade Modeling of Pixelated Scintillator Detectors for X-Ray Imaging

    Microsoft Academic Search

    Ho Kyung Kim; Seung Man Yun; Jong Soo Ko; Gyuseong Cho; Thorsten Graeve

    2008-01-01

    We have modeled the signal and noise propagation in a pixelated scintillator detector by using the cascaded linear-systems transfer theory. The main difference from the conventional homogeneous scintillator detector is the additional X-ray quantum sampling process at the beginning stage of the cascaded model. The additional sampling stage is expressed as a multiplication of the fill factor of the pixelated

  1. Signal to Noise Ratio of APD-Based Monolithic Scintillator Detectors for High Resolution PET

    Microsoft Academic Search

    Marnix C. Maas; Dennis R. Schaart; Herman T. van Dam; Jan Huizenga; J. C. Brouwer; Peter Bruyndonckx; Cedric Lemaitre; Carel W. E. van Eijk

    2008-01-01

    Monolithic scintillator detectors, consisting of several cm3 of scintillating material coupled to one or more Hamamatsu S8550 avalanche photodiode (APD) arrays, are proposed as detectors for high resolution positron emission tomography (PET). In this work, the factors contributing to the variance on the signals are investigated, and their effects on the energy, time and spatial resolutions are analyzed. Good agreement

  2. 3D position estimation using an artificial neural network for a continuous scintillator PET detector.

    PubMed

    Wang, Y; Zhu, W; Cheng, X; Li, D

    2013-03-01

    Continuous crystal based PET detectors have features of simple design, low cost, good energy resolution and high detection efficiency. Through single-end readout of scintillation light, direct three-dimensional (3D) position estimation could be another advantage that the continuous crystal detector would have. In this paper, we propose to use artificial neural networks to simultaneously estimate the plane coordinate and DOI coordinate of incident ? photons with detected scintillation light. Using our experimental setup with an '8 + 8' simplified signal readout scheme, the training data of perpendicular irradiation on the front surface and one side surface are obtained, and the plane (x, y) networks and DOI networks are trained and evaluated. The test results show that the artificial neural network for DOI estimation is as effective as for plane estimation. The performance of both estimators is presented by resolution and bias. Without bias correction, the resolution of the plane estimator is on average better than 2 mm and that of the DOI estimator is about 2 mm over the whole area of the detector. With bias correction, the resolution at the edge area for plane estimation or at the end of the block away from the readout PMT for DOI estimation becomes worse, as we expect. The comprehensive performance of the 3D positioning by a neural network is accessed by the experimental test data of oblique irradiations. To show the combined effect of the 3D positioning over the whole area of the detector, the 2D flood images of oblique irradiation are presented with and without bias correction. PMID:23399593

  3. 3D position estimation using an artificial neural network for a continuous scintillator PET detector

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Zhu, W.; Cheng, X.; Li, D.

    2013-03-01

    Continuous crystal based PET detectors have features of simple design, low cost, good energy resolution and high detection efficiency. Through single-end readout of scintillation light, direct three-dimensional (3D) position estimation could be another advantage that the continuous crystal detector would have. In this paper, we propose to use artificial neural networks to simultaneously estimate the plane coordinate and DOI coordinate of incident ? photons with detected scintillation light. Using our experimental setup with an ‘8 + 8’ simplified signal readout scheme, the training data of perpendicular irradiation on the front surface and one side surface are obtained, and the plane (x, y) networks and DOI networks are trained and evaluated. The test results show that the artificial neural network for DOI estimation is as effective as for plane estimation. The performance of both estimators is presented by resolution and bias. Without bias correction, the resolution of the plane estimator is on average better than 2 mm and that of the DOI estimator is about 2 mm over the whole area of the detector. With bias correction, the resolution at the edge area for plane estimation or at the end of the block away from the readout PMT for DOI estimation becomes worse, as we expect. The comprehensive performance of the 3D positioning by a neural network is accessed by the experimental test data of oblique irradiations. To show the combined effect of the 3D positioning over the whole area of the detector, the 2D flood images of oblique irradiation are presented with and without bias correction.

  4. A novel method to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

    SciTech Connect

    Shao Yiping; Yao Rutao; Ma Tianyu [Department of Imaging Physics, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 600, Houston, Texas 77030 (United States); Department of Nuclear Medicine, State University of New York at Buffalo, 105 Parker Hall, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Nuclear Medicine, State University of New York at Buffalo, 105 Parker Hall, 3435 Main Street, Buffalo, New York 14214 and Department of Engineering Physics, Tsinghua University, Beijing, 100084 (China)

    2008-12-15

    The detection of depth-of-interaction (DOI) is a critical detector capability to improve the PET spatial resolution uniformity across the field-of-view and will significantly enhance, in particular, small bore system performance for brain, breast, and small animal imaging. One promising technique of DOI detection is to use dual-ended-scintillator readout that uses two photon sensors to detect scintillation light from both ends of a scintillator array and estimate DOI based on the ratio of signals (similar to Anger logic). This approach needs a careful DOI function calibration to establish accurate relationship between DOI and signal ratios, and to recalibrate if the detection condition is shifted due to the drift of sensor gain, bias variations, or degraded optical coupling, etc. However, the current calibration method that uses coincident events to locate interaction positions inside a single scintillator crystal has severe drawbacks, such as complicated setup, long and repetitive measurements, and being prone to errors from various possible misalignments among the source and detector components. This method is also not practically suitable to calibrate multiple DOI functions of a crystal array. To solve these problems, a new method has been developed that requires only a uniform flood source to irradiate a crystal array without the need to locate the interaction positions, and calculates DOI functions based solely on the uniform probability distribution of interactions over DOI positions without knowledge or assumption of detector responses. Simulation and experiment have been studied to validate the new method, and the results show that the new method, with a simple setup and one single measurement, can provide consistent and accurate DOI functions for the entire array of multiple scintillator crystals. This will enable an accurate, simple, and practical DOI function calibration for the PET detectors based on the design of dual-ended-scintillator readout. In addition, the new method can be generally applied to calibrating other types of detectors that use the similar dual-ended readout to acquire the radiation interaction position.

  5. (Effects of ionizing radiation on scintillators and other particle detectors)

    SciTech Connect

    Proudfoot, J.

    1992-01-01

    It is my task to summarise the great variety of topics (covering a refreshing mix of physics, chemistry and technology) presented at this conference, which has focused on the effects of ionising radiation on scintillators and other particle detectors. One of the reasons and the central interest of many of the participants was the use of such detectors in experiments at two future large hadron colliders: the Superconducting Super Collider to be operating outside of Dallas in the United States by the turn of the decade and its European counterpart the Large Hadron Collider to be operating outside of Geneva in Switzerland on a similar time scale. These accelerators are the apple of the high energy physicist's eye.'' Their goal is to uncover the elusive Higgs particle and thereby set the cornerstone in our current knowledge of elementary particle interactions. This is the Quest, and from this lofty height the presentations rapidly moved on to the specific questions of experimental science: how such an experiment is carried out; why radiation damage is an issue; how radiation damage affects detectors; which factors affect radiation damage characteristics; which factors are not affected by radiation damage; and how better detectors may be constructed. These were the substance of this conference.

  6. Influence of depth of interaction upon the performance of scintillator detectors.

    PubMed

    Brown, Mark S; Gundacker, Stefan; Taylor, Alaric; Tummeltshammer, Clemens; Auffray, Etiennette; Lecoq, Paul; Papakonstantinou, Ioannis

    2014-01-01

    The uncertainty in time of particle detection within a scintillator detector, characterised by the coincidence time resolution (CTR), is explored with respect to the interaction position within the scintillator crystal itself. Electronic collimation between two scintillator detectors is utilised to determine the CTR with depth of interaction (DOI) for different materials, geometries and wrappings. Significantly, no relationship between the CTR and DOI is observed within experimental error. Confinement of the interaction position is seen to degrade the CTR in long scintillator crystals by 10%. PMID:24875832

  7. Gamma-Beta-Neutron Detectors Set-Up at ALTO

    SciTech Connect

    Testov, D.; Penionzhkevich, Yu.; Smirnov, V.; Sokol, E. [Flerov laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna (Russian Federation); Ancelin, S.; Ibrahim, F.; Niikura, M.; Tastet, B.; Verney, D. [Institute de Physique Nucleaire d'Orsay (France)

    2010-04-30

    A multi detection system consisted of 90 {sup 3}He counters, gamma detector and beta detector has been installed at beamline of the accelerator complex ALTO. The system allows performing direct measurements of probability of delayed neutron emission from spontaneous fission fragments. A trial experiment was carried out to test the detection system created.

  8. Physics Potential of an Advanced Scintillation Detector: Introducing THEIA

    E-print Network

    Gabriel D. Orebi Gann; for the THEIA Interest Group

    2015-04-30

    The recent development of water-based liquid scintillator and the concurrent development of high-efficiency and high-precision-timing light sensors has opened up the possibility for a new kind of large-scale detector capable of a very broad program of physics. The program would span topics in nuclear, high-energy, and astrophysics, ranging from a next-generation neutrinoless double beta decay search capable of covering the inverted hierarchy region of phase space, to supernova neutrino detection, nucleon decay searches, and measurement of the neutrino mass hierarchy and CP violating phase. This paper describes the technical breakthroughs that led to this possibility, and the broad physics program thus enabled. This paper is a summary of a talk presented at the NuPhys 2014 conference in London.

  9. Use of internal scintillator radioactivity to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

    PubMed Central

    Bircher, Chad; Shao, Yiping

    2012-01-01

    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?×?1.5 and 2.0?×?2.0 mm2 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 to accurately measure DOI function in PET detectors, regardless of scintillator geometry or surface finish. Because an external radiation source is not needed, this method of DOI function measurement can be practically applied to individual PET detectors as well as assembled systems. PMID:22320787

  10. Exposure rate by the spectrum dose index method using plastic scintillator detectors.

    PubMed

    Proctor, Alan; Wellman, Jeffrey

    2012-04-01

    The spectrum dose index (SDI) method was tested for use with data from plastic scintillator detectors by irradiating a typical portal detector system using different gamma sources and natural background. Measurements were compared with exposure rates simultaneously measured using a calibrated pressurised ion chamber. It was found that a modified SDI algorithm could be used to calculate exposure rates for these detectors despite the lack of photopeaks in plastic scintillator spectra. PMID:21712256

  11. Ultra precise timing with SiPM-based TOF PET scintillation detectors

    Microsoft Academic Search

    Stefan Seifert; Ruud Vinke; Herman T. van Dam; Herbert Löhner; Peter Dendooven; Freek J. Beekman; D. R. Schaart

    2009-01-01

    The combination of SiPMs with fast and bright scintillators, such as LaBr3:Ce, seems very promising for application in time-of-flight (TOF) PET. We therefore conducted a series of experiments with the goal of obtaining the best possible timing resolution with SiPM-based scintillation detectors in order to establish a bench mark for future experiments with different detector designs. The detectors employed in

  12. Operation characteristics of ionizing radiation detectors based on inorganic and plastic scintillators for nuclear physics and medical instrumentation

    Microsoft Academic Search

    M. Globus; B. Grinyov

    1996-01-01

    Main operation characteristics of radiation detectors, using various scintillation substances, are calculated on the base of a realistic optical model of a scintillator. The calculation method takes account of a mirror-type maximum of the diffuse reflection indicatrix which is important for light collection in a scintillator. The comparison is carried out between various cases. Differing in the scintillator geometry, the

  13. Operation characteristics of ionizing radiation detectors based on inorganic and plastic scintillators for nuclear physics and medical instrumentation

    Microsoft Academic Search

    M. Globus; B. Grinyov

    1995-01-01

    Main operation characteristics of radiation detectors, using various scintillation substances, are calculated on the base of a realistic optical model of a scintillator. The calculation method takes account of a mirror-type maximum of the diffuse reflection indicatrix which is important for light collection in a scintillator. The comparison is carried out between various cases differing in the scintillator geometry, the

  14. A new compact position-sensitive PMT for scintillation detectors

    SciTech Connect

    Nagai, S.; Shimoi, H.; Yoshizawa, Y [Hamamatsu Photonics K.K., Toyooka (Japan). Electron Tube Center] [Hamamatsu Photonics K.K., Toyooka (Japan). Electron Tube Center; Watanabe, M. [Hamamatsu Photonics K.K., Hirakuchi (Japan). Central Research Lab.] [Hamamatsu Photonics K.K., Hirakuchi (Japan). Central Research Lab.; Liu, H. [Zhejiang Univ. (China). State Key Lab. of Modern Optical Instrumentation] [Zhejiang Univ. (China). State Key Lab. of Modern Optical Instrumentation

    1999-06-01

    A new compact position-sensitive photomultiplier tube (PS-PMT), Hamamatsu R7600-C12, has been developed for scintillation detectors. The PS-PMT has 11 stages of metal channel dynodes and 6(X) + 6(Y) crossed plate anodes in a 25.7 mm square x 20 mm high metal can package, where the photo-sensitive area is 22 mm square. The performance of the PS-PMT was evaluated in terms of applicability to radiation imaging systems. In comparison with the former type of PS-PMT (Hamamatsu R5900-C8), the new PS-PMT provides smaller light spread and better position response. Also, by removing the flange at the bottom of the PS-PMT, the ratio of the effective area to the outward area is increased. The spatial resolution capability was demonstrated by imaging a stratified LSO array having an element of 1.8 mm x 1.8 mm x 10 mm. Each crystal element is clearly identified on the image map with 662 keV uniform gamma-ray irradiation. This paper describes the characteristics of the new PS-PMT and the experimental results for a gamma-ray imaging detector.

  15. High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

    DOEpatents

    Chiles, Marion M. (Knoxville, TN); Mihalczo, John T. (Oak Ridge, TN); Blakeman, Edward D. (Oak Ridge, TN)

    1989-01-01

    A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

  16. High-efficiency scintillation detector for combined detection of thermal and fast neutrons and gamma radiation

    DOEpatents

    Chiles, M.M.; Mihalczo, J.T.; Blakeman, E.D.

    1987-02-27

    A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation event count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

  17. Testing a new NIF neutron time-of-flight detector with a bibenzyl scintillator on OMEGA.

    PubMed

    Glebov, V Yu; Forrest, C; Knauer, J P; Pruyne, A; Romanofsky, M; Sangster, T C; Shoup, M J; Stoeckl, C; Caggiano, J A; Carman, M L; Clancy, T J; Hatarik, R; McNaney, J; Zaitseva, N P

    2012-10-01

    A new neutron time-of-flight (nTOF) detector with a bibenzyl crystal as a scintillator has been designed and manufactured for the National Ignition Facility (NIF). This detector will replace a nTOF20-Spec detector with an oxygenated xylene scintillator currently operational on the NIF to improve the areal-density measurements. In addition to areal density, the bibenzyl detector will measure the D-D and D-T neutron yield and the ion temperature of indirect- and direct-drive-implosion experiments. The design of the bibenzyl detector and results of tests on the OMEGA Laser System are presented. PMID:23126836

  18. An LSO scintillator array for a PET detector module with depth of interaction measurement

    Microsoft Academic Search

    J. S. Huber; W. W. Moses; M. S. Andreaco; O. Petterson

    2001-01-01

    Presents construction methods and performance results for a production scintillator array of 64 optically isolated, 3 mm×3 mm×30 mm sized LSO crystals. This scintillator array has been developed for a PET detector module consisting of the 8×8 LSO array coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of

  19. Study of Solid State Photon Detectors Read Out of Scintillator Tiles

    E-print Network

    A. Calcaterra; R. de Sangro; G. Finocchiaro; E. Kuznetsova; P. Patteri; M. Piccolo

    2009-01-14

    We present preliminary results on efficiency and light collection uniformity read out performances of different assemblies of scintillator tiles, coupled with solid state photon detectors of different make. Our test beam data suggest that the use of 2 mm scintillator tiles without wavelength shifting fibers may be possible in an ILC hadron calorimeter.

  20. Investigations of surface coatings to reduce memory effect in plastic scintillator detectors used for radioxenon detection

    Microsoft Academic Search

    L. Bläckberg; A. Fay; I. Jõgi; S. Biegalski; M. Boman; K. Elmgren; T. Fritioff; A. Johansson; L. Mårtensson; F. Nielsen; A. Ringbom; M. Rooth; H. Sjöstrand; M. Klintenberg

    2011-01-01

    In this work Al2O3 and SiO2 coatings are tested as Xe diffusion barriers on plastic scintillator substrates. The motivation is improved beta–gamma coincidence detection systems, used to measure atmospheric radioxenon within the verification regime of the Comprehensive Nuclear-Test-Ban Treaty. One major drawback with the current setup of these systems is that the radioxenon tends to diffuse into the plastic scintillator

  1. 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.

  2. Detection of Extensive Cosmic Air Showers by Small Scintillation Detectors with Wavelength-Shifting Fibres

    ERIC Educational Resources Information Center

    Aiola, Salvatore; La Rocca, Paola; Riggi, Francesco; Riggi, Simone

    2012-01-01

    A set of three small scintillation detectors was employed to measure correlated events due to the passage of cosmic muons originating from extensive air showers. The coincidence rate between (any) two detectors was extracted as a function of their relative distance. The difference between the arrival times in three non-aligned detectors was used…

  3. Monte Carlo simulation of the standardization of 22Na using scintillation detector arrays.

    PubMed

    Sato, Y; Murayama, H; Yamada, T; Hasegawa, T; Oda, K; Unno, Y; Yunoki, A

    2010-01-01

    In order to calibrate PET devices by a sealed point source, we contrived an absolute activity measurement method for the sealed point source using scintillation detector arrays. This new method was verified by EGS5 Monte Carlo simulation. PMID:20083411

  4. A new fission-fragment detector to complement the CACTUS-SiRi setup at the Oslo Cyclotron Laboratory

    E-print Network

    Tamás Gábor Tornyi; Andreas Görgen; Magne Guttormsen; Ann-Cecilie Larsen; Sunniva Siem; Attila Krasznahorkay; Lóránt Csige

    2013-12-02

    An array of Parallel Plate Avalanche Counters (PPAC) for the detection of heavy ions has been developed. The new device, NIFF (Nuclear Instrument for Fission Fragments), consists of four individual detectors and covers $60\\%$ of 2$\\pi$. It was designed to be used in conjunction with the SiRi array of ${\\Delta}E-E$ silicon telescopes for light charged particles and fits into the CACTUS array of 28 large-volume NaI scintillation detectors at the Oslo Cyclotron Laboratory. The low-pressure gas-filled PPACs are sensitive for the detection of fission fragments, but are insensitive to scattered beam particles of light ions or light-ion ejectiles. The PPAC detectors of NIFF have good time resolution and can be used either to select or to veto fission events in in-beam experiments with light-ion beams and actinide targets. The powerful combination of SiRi, CACTUS, and NIFF provides new research opportunities for the study of nuclear structure and nuclear reactions in the actinide region. The new setup is particularly well suited to study the competition of fission and $\\gamma$ decay as a function of excitation energy.

  5. A new fission-fragment detector to complement the CACTUS-SiRi setup at the Oslo Cyclotron Laboratory

    E-print Network

    Tornyi, Tamás Gábor; Guttormsen, Magne; Larsen, Ann-Cecilie; Siem, Sunniva; Krasznahorkay, Attila; Csige, Lóránt

    2013-01-01

    An array of Parallel Plate Avalanche Counters (PPAC) for the detection of heavy ions has been developed. The new device, NIFF (Nuclear Instrument for Fission Fragments), consists of four individual detectors and covers $60\\%$ of 2$\\pi$. It was designed to be used in conjunction with the SiRi array of ${\\Delta}E-E$ silicon telescopes for light charged particles and fits into the CACTUS array of 28 large-volume NaI scintillation detectors at the Oslo Cyclotron Laboratory. The low-pressure gas-filled PPACs are sensitive for the detection of fission fragments, but are insensitive to scattered beam particles of light ions or light-ion ejectiles. The PPAC detectors of NIFF have good time resolution and can be used either to select or to veto fission events in in-beam experiments with light-ion beams and actinide targets. The powerful combination of SiRi, CACTUS, and NIFF provides new research opportunities for the study of nuclear structure and nuclear reactions in the actinide region. The new setup is particularly...

  6. The large scintillation charged particles detector of the Tien-Shan complex “ATHLET”

    Microsoft Academic Search

    G. I. Britvich; S. K. Chernichenko; A. P. Chubenko; Yu. V. Gilitsky; A. E. Kushnirenko; E. A. Mamidzhanyan; V. P. Pavlyuchenko; I. V. Shein; A. P. Soldatov; A. L. Shepetov; V. G. Vasil’chenko

    2006-01-01

    A new type of scintillation detectors for the mountain cosmic ray complex ATHLET is designed at the Institute for High Energy Physics (IHEP). The detector is implemented on the basis of 10mm thick molded polystyrene plates in conjunction with wavelength shifting fibers. It has a 1×1m2 sensitive area, ?99% registration efficiency of charged particles and a homogeneity of the scintillation

  7. Investigation of the properties of new scintillator LYSO and recent LSO scintillators for phoswich PET detectors

    Microsoft Academic Search

    Catherine Michelle Pepin; Anne-Laure Perrot; Philippe Bérard; Claude Pépin; Daniel Houde; Roger Lecomte; Charles L. Melcher; Henri Dautet

    2002-01-01

    The luminescence and nuclear spectroscopic properties of the new cerium-doped rare-earth scintillator lutetium-yttrium oxyorthosilicate (Lu0.6Y1.4SiO5:Ce, LYSO) were investigated and compared to those of both recent and older LSO crystals. UV-excited luminescent spectra outline important similarities between LYSO and LSO scintillators. The two distinct Ce1 and Ce2 luminescence mechanisms previously identified in LSO are also present in LYSO scintillators. The energy

  8. Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations

    SciTech Connect

    Sótér, A., E-mail: anna.soter@mpq.mpg.de [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Todoroki, K.; Kobayashi, T. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)] [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Barna, D. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan) [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Wigner Research Center of Physics, H-1525 Budapest (Hungary); Horváth, D. [Wigner Research Center of Physics, H-1525 Budapest (Hungary)] [Wigner Research Center of Physics, H-1525 Budapest (Hungary); Hori, M. [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany) [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    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.

  9. Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations

    E-print Network

    A. Sótér; K. Todoroki; T. Kobayashi; D. Barna; D. Horvath; M. Hori

    2014-03-03

    The Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) 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 x 1 mm^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.

  10. Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations.

    PubMed

    Sótér, A; Todoroki, K; Kobayashi, T; Barna, D; Horváth, D; Hori, M

    2014-02-01

    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(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. PMID:24593349

  11. Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations

    E-print Network

    Sótér, A; Kobayashi, T; Barna, D; Horvath, D; Hori, M

    2014-01-01

    The Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) 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 x 1 mm^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 a...

  12. In vivo dosimeters for HDR brachytherapy: A comparison of a diamond detector, MOSFET, TLD, and scintillation detector

    Microsoft Academic Search

    Jamil Lambert; Tatsuya Nakano; Sue Law; Justin Elsey; David R. McKenzie; Natalka Suchowerska

    2007-01-01

    The large dose gradients in brachytherapy necessitate a detector with a small active volume for accurate dosimetry. The dosimetric performance of a novel scintillation detector (BrachyFOD{sup TM}) is evaluated and compared to three commercially available detectors, a diamond detector, a MOSFET, and LiF TLDs. An ¹⁹²Ir HDR brachytherapy source is used to measure the depth dependence, angular dependence, and temperature

  13. Evaluation of a reflective coating for an organic scintillation detector

    NASA Astrophysics Data System (ADS)

    Tarancón, A.; Marin, E.; Tent, J.; Rauret, G.; Garcia, J. F.

    2012-05-01

    A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO2, were also tested to determine the one with the best performance and lowest radioactivity content. In a first experiment, we evaluated the capability of the reflective coating by measuring 90Sr/90Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt). The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides (40K, 226Ra and 228Ra) in the EJ510. On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).

  14. Optical simulation of monolithic scintillator detectors using GATE/GEANT4.

    PubMed

    van der Laan, D J Jan; Schaart, Dennis R; Maas, Marnix C; Beekman, Freek J; Bruyndonckx, Peter; van Eijk, Carel W E

    2010-03-21

    Much research is being conducted on position-sensitive scintillation detectors for medical imaging, particularly for emission tomography. Monte Carlo simulations play an essential role in many of these research activities. As the scintillation process, the transport of scintillation photons through the crystal(s), and the conversion of these photons into electronic signals each have a major influence on the detector performance; all of these processes may need to be incorporated in the model to obtain accurate results. In this work the optical and scintillation models of the GEANT4 simulation toolkit are validated by comparing simulations and measurements on monolithic scintillator detectors for high-resolution positron emission tomography (PET). We have furthermore made the GEANT4 optical models available within the user-friendly GATE simulation platform (as of version 3.0). It is shown how the necessary optical input parameters can be determined with sufficient accuracy. The results show that the optical physics models of GATE/GEANT4 enable accurate prediction of the spatial and energy resolution of monolithic scintillator PET detectors. PMID:20182005

  15. Plastic scintillator-based radiation detector for mobile radiation detection system against nuclear\\/radiological terrorism

    Microsoft Academic Search

    Sung-Woo Kwak; Ho-Sik Yoo; Sung Soon Jang; Jung Soo Kim; Wan-Ki Yoon; In Sub Jun; Kwang Hyun Kim

    2009-01-01

    Illicit trafficking of nuclear or radioactive materials has become a serious world wide problem. Due to operational constraints of radiation detection system for such nuclear security application, a radiation detector with large effective area is needed to maximize its sensitivity. This paper suggests a new method of using plastic scintillation detector as a cost-effective mobile radiation detection system. Monte Carlo

  16. Analysis of timing performance for an APD-LSO scintillation detector

    Microsoft Academic Search

    Michael E. Casey; Carlyle Reynolds; David M. Binkley; James M. Rochelle

    2003-01-01

    The timing performance of a detector designed for application in positron emission tomography (PET) directly effects image noise in the form of random events. The application of avalanche photodiodes in a PET scintillation detector requires careful analysis and design to achieve timing performance comparable to photomultiplier based systems. In this paper, we present a robust technique that allows the analysis

  17. Continuous Scintillator Detector Blocks for Simultaneous Pet-Mr Imaging of the Human Brain

    NASA Astrophysics Data System (ADS)

    Rato Mendes, Pedro

    2010-04-01

    Continuous scintillator detector blocks have several advantages over pixelated designs, presenting a larger active volume and a lower cost with comparable or better energy and spatial resolutions. In this paper we describe the operation of continuous detector blocks for positron emission tomography (PET) and their suitability for multimodality imaging operating inside a magnetic resonance (MR) scanner. This detector technology is being used on a full-scale clinical scanner for human brain PET studies presently under development at Ciemat. Results will be presented on the laboratory characterization of monolithic scintillators coupled to APD matrices with ASIC readout, including images of point sources from a prototype dual-head demonstrator illustrating the potential of continuous scintillator detector blocks for high-resolution PET-MR imaging.

  18. Advanced Scintillator Detector Concept (ASDC): A Concept Paper on the Physics Potential of Water-Based Liquid Scintillator

    E-print Network

    J. R. Alonso; N. Barros; M. Bergevin; A. Bernstein; L. Bignell; E. Blucher; F. Calaprice; J. M. Conrad; F. B. Descamps; M. V. Diwan; D. A. Dwyer; S. T. Dye; A. Elagin; P. Feng; C. Grant; S. Grullon; S. Hans; D. E. Jaffe; S. H. Kettell; J. R. Klein; K. Lande; J. G. Learned; K. B. Luk; J. Maricic; P. Marleau; A. Mastbaum; W. F. McDonough; L. Oberauer; G. D. Orebi Gann; R. Rosero; S. D. Rountree; M. C. Sanchez; M. H. Shaevitz; T. M. Shokair; M. B. Smy; A. Stahl; M. Strait; R. Svoboda; N. Tolich; M. R. Vagins; K. A. van Bibber; B. Viren; R. B. Vogelaar; M. J. Wetstein; L. Winslow; B. Wonsak; E. T. Worcester; M. Wurm; M. Yeh; C. Zhang

    2014-10-24

    The recent development of Water-based Liquid Scintillator (WbLS), and the concurrent development of high-efficiency and high-precision-timing light sensors, has opened up the possibility for a new kind of large-scale detector capable of a very broad program of physics. The program would include determination of the neutrino mass hierarchy and observation of CP violation with long-baseline neutrinos, searches for proton decay, ultra-precise solar neutrino measurements, geo- and supernova neutrinos including diffuse supernova antineutrinos, and neutrinoless double beta decay. We outline here the basic requirements of the Advanced Scintillation Detector Concept (ASDC), which combines the use of WbLS, doping with a number of potential isotopes for a range of physics goals, high efficiency and ultra-fast timing photosensors, and a deep underground location. We are considering such a detector at the Long Baseline Neutrino Facility (LBNF) far site, where the ASDC could operate in conjunction with the liquid argon tracking detector proposed by the LBNE collaboration. The goal is the deployment of a 30-100 kiloton-scale detector, the basic elements of which are being developed now in experiments such as WATCHMAN, ANNIE, SNO+, and EGADS.

  19. High energy gamma-ray spectroscopy with LaBr 3 scintillation detectors

    Microsoft Academic Search

    F. G. A. Quarati; Alan Owens; P. Dorenbos; J. T. M. de Haas; G. Benzoni; N. Blasi; C. Boiano; S. Brambilla; F. Camera; R. Alba; G. Bellia; C. Maiolino; D. Santonocito; M. Ahmed; N. Brown; S. Stave; H. R. Weller; Y. K. Wu

    2011-01-01

    Lanthanum bromide scintillation detectors produce very high light outputs (?60,000ph\\/MeV) within a very short decay time (typically ?20ns) which means that high instantaneous currents can be generated in the photocathode and dynode chain of the photomultiplier tube (PMT) used for the scintillation readout. The net result is that signal saturation can occur long before the recommended PMT biasing conditions can

  20. Cerium doped GSO scintillators and its application to position sensitive detectors

    Microsoft Academic Search

    H. Ishibashi; K. Shimizu; K. Susa; S. Kubota

    1989-01-01

    The dependence of the light output and the decay times of Ce doped GdâSiOâ on Ce concentration is measured. By using the difference in decay times on Ce concentration for GSO(Ce), the combination of different concentration of GSO(Ce) scintillators is shown to be useful as position sensitive detectors. A Ce doped GdâSiOâ (GSO(Ce)) single crystal is an excellent scintillator featuring,

  1. Simulating response functions and pulse shape discrimination for organic scintillation detectors with Geant4

    NASA Astrophysics Data System (ADS)

    Hartwig, Zachary S.; Gumplinger, Peter

    2014-02-01

    We present new capabilities of the Geant4 toolkit that enable the precision simulation of organic scintillation detectors within a comprehensive Monte Carlo code for the first time. As of version 10.0-beta, the Geant4 toolkit models the data-driven photon production from any user-defined scintillator, photon transportation through arbitrarily complex detector geometries, and time-resolved photon detection at the light readout device. By fully specifying the optical properties and geometrical configuration of the detector, the user can simulate response functions, photon transit times, and pulse shape discrimination. These capabilities enable detector simulation within a larger experimental environment as well as computationally evaluating novel scintillators, detector geometry, and light readout configurations. We demonstrate agreement of Geant4 with the NRESP7 code and with experiments for the spectroscopy of neutrons and gammas in the ranges 0-20 MeV and 0.511-1.274 MeV, respectively, using EJ301-based organic scintillation detectors. We also show agreement between Geant4 and experimental modeling of the particle-dependent detector pulses that enable simulated pulse shape discrimination.

  2. Combinatorial Screening of Advanced Scintillators for High Resolution X-ray Detectors

    SciTech Connect

    Cheng, Shifan; Tao, Dejie; Lynch, Michael; Yuan, Xianglong; Li, Yiqun

    2008-05-12

    The lack of efficient scintillators is a major problem for developing powerful x-ray detectors that are widely used in homeland security, industrial and scientific research. Intematix has developed and applied a high throughput screening process and corresponding crystal growth technology to significantly speed up the discovery process for new efficient scintillators. As a result, Intematix has invented and fabricated three new scintillators both in powder and bulk forms, which possess promising properties such as better radiation hardness and better matching for silicon diode.

  3. Wurtzite Gallium Nitride as a scintillator detector for alpha particles (a Geant4 simulation)

    NASA Astrophysics Data System (ADS)

    Taheri, A.; Sheidaiy, M.

    2015-05-01

    Gallium Nitride has become a very popular material in electronics and optoelectronics. Because of its interesting properties, it is suitable for a large range of applications. This material also shows very good scintillation properties that make it a possible candidate for use as a charged particles scintillator detector. In this work, we simulated the scintillation and optical properties of the gallium nitride in the presence of alpha particles using Geant4. The results show that gallium nitride can be an appropriate choice for this purpose.

  4. 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.

  5. Comparative Investigation of the Performance of ZnO-Based Scintillators for Use as ?-Particle Detectors

    SciTech Connect

    Neal, John S [ORNL; Boatner, Lynn A [ORNL; Giles, N. C. [West Virginia University; Halliburton, L. E. [West Virginia University; Derenzo, S. E. [Lawrence Berkeley National Laboratory (LBNL); Bourret-Courchesne, E. D. [Lawrence Berkeley National Laboratory (LBNL)

    2006-01-01

    As part of a comprehensive investigation of the scintillation properties of zinc-oxide-based scintillators, four samples of gallium-doped zinc oxide (ZnO) powders have been characterized by means of X-ray excitation, {alpha}-particle excitation, and temperature-dependent photoluminescence (PL). The ultimate goals of these studies are, first, to understand the scintillation mechanisms that are operative in various members of the ZnO family of scintillators, and, subsequently, to use this knowledge in order to improve the radiation-detection performance of ZnO. These samples have been considered for use in an {alpha}-detector for installation in a deuterium-tritium (D-T) neutron generator. All of the samples demonstrated principal decay time components on the order of 1 ns. PL measurements of the four powder samples did not unequivocally support any of the discussed models. Excitonic and shallow acceptor models, however, share a common starting point for future investigations. The Lawrence Berkeley National Laboratory (LBNL) 3518 sample was found to be the most promising candidate, in terms of fast light output, for replacing the Nuclear Enterprises Technology sample for use in a ZnO:Ga-based {alpha}-particle detector. While the nature of the luminescence center(s) or the energy transfer mechanisms actually responsible for scintillation are not yet clearly understood, ZnO:Ga remains a highly desirable candidate scintillator for use in an {alpha}-detector for installation in a D-T neutron generator and extended investigations of the fundamental mechanisms and scintillation parameters that are operative in ZnO:Ga scintillators are continuing.

  6. Hard x-ray and gamma-ray imaging and spectroscopy using scintillators coupled to silicon drift detectors

    Microsoft Academic Search

    P. Lechner; R. Eckhard; C. Fiorini; A. Gola; A. Longoni; A. Niculae; R. Peloso; H. Soltau; L. Strüder

    2008-01-01

    Silicon Drift Detectors (SDDs) are used as low-capacitance photon detectors for the optical light emitted by scintillators. The scintillator crystal is directly coupled to the SDD entrance window. The entrance window's transmittance can be optimized for the scintillator characteristic by deposition of a wavelength-selective anti-reflective coating. Compared to conventional photomultiplier tubes the SDD readout offers improved energy resolution and avoids

  7. 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.

  8. A scintillator based muon and KLong detector for the Belle II experiment

    E-print Network

    T. Aushev; D. Z. Besson; K. Chilikin; R. Chistov; M. Danilov; P. Katrenko; R. Mizuk; G. Pakhlova; P. Pakhlov; V. Rusinov; E. Solovieva; E. Tarkovsky; I. Tikhomirov; T. Uglov

    2015-04-03

    A new muon and K_Long detector based on scintillators will be used for the endcap and inner barrel regions in the Belle II experiment, currently under construction. The increased luminosity of the e+e- SuperKEKB collider entails challenging detector requirements. We demonstrate that relatively inexpensive polystyrene scintillator stips with wave length shifting fibers ensure a sufficient light yield at the Silcon PhotoMultiplier (SiPM) photodetector, are robust and provide improved physics performance for the Belle II experiment compared to its predecessor, Belle.

  9. A SCINTILLATION CHAMBER-IMAGE INTENSIFIER BEAM PROFILE DETECTOR

    Microsoft Academic Search

    J. R. Waters; G. T. Reynolds; D. B. Searl; R. A. Zdanis

    1961-01-01

    A scintillation chamber was mounted on a single stage image intensifier ; which was lens coupled to an intensifier orthicon in a closed circuit television ; system. Charged particles entered the ends and travelled down the length of the ; filaments causing fiashes of light which were amplified and displayed on the ; monitor kinescope. This system was used as

  10. A Measurement of the Scintillation Light Yield in CD4 Using a Photosensitive GEM Detector

    SciTech Connect

    Azmoun, B.; Azmoun, B.; Caccavano, A.; Rumore, M.; Sinsheimer, J.; Smirnov, N.; Stoll, S.; Woody, C.

    2010-08-01

    The absolute photon yield of scintillation light produced by highly ionizing particles in pure CF{sub 4} has been measured using a photosensitive Gas Electron Multiplier (GEM) detector. The detector consists of two standard GEMs and a CsI coated GEM which acts as a photocathode that is sensitive to the 160 nm scintillation light produced in CF{sub 4}. The light yield was determined in terms of the number of scintillation photons emitted into a 4{pi} solid angle produced per MeV of energy deposited in the gas by a 5.5 MeV alpha particle and found to be 314 {+-} 15 photons per MeV. The quantum yield was determined using a fitting method to determine the number of photoelectrons from the measured pulse height distribution, and by an independent method using the measured gain of the GEM detector. The effect of scintillation light in CF{sub 4} on the performance of Cherenkov detectors, such as the PHENIX Hadron Blind Detector (HBD) at RHIC, is also discussed.

  11. A fast microchannel plate-scintillator detector for velocity map imaging and imaging mass spectrometry.

    PubMed

    Winter, B; King, S J; Brouard, M; Vallance, C

    2014-02-01

    The time resolution achievable using standard position-sensitive ion detectors, consisting of a chevron pair of microchannel plates coupled to a phosphor screen, is primarily limited by the emission lifetime of the phosphor, around 70 ns for the most commonly used P47 phosphor. We demonstrate that poly-para-phenylene laser dyes may be employed extremely effectively as scintillators, exhibiting higher brightness and much shorter decay lifetimes than P47. We provide an extensive characterisation of the properties of such scintillators, with a particular emphasis on applications in velocity-map imaging and microscope-mode imaging mass spectrometry. The most promising of the new scintillators exhibits an electron-to-photon conversion efficiency double that of P47, with an emission lifetime an order of magnitude shorter. The new scintillator screens are vacuum stable and show no signs of signal degradation even over longer periods of operation. PMID:24593353

  12. Expected performance of an ideal liquid argon neutrino detector with enhanced sensitivity to scintillation light

    NASA Astrophysics Data System (ADS)

    Sorel, M.

    2014-10-01

    Scintillation light is used in liquid argon (LAr) neutrino detectors to provide a trigger signal, veto information against cosmic rays, and absolute event timing. In this work, we discuss additional opportunities offered by detectors with enhanced sensitivity to scintillation light, that is with light collection efficiencies of about 10-3. We focus on two key detector performance indicators for neutrino oscillation physics: calorimetric neutrino energy reconstruction and neutrino/antineutrino separation in a non-magnetized detector. Our results are based on detailed simulations, with neutrino interactions modelled according to the GENIE event generator, while the charge and light responses of a large LAr ideal detector are described by the Geant4 and NEST simulation tools. A neutrino energy resolution as good as 3.3% RMS for 4 GeV electron neutrino charged-current interactions can in principle be obtained in a large detector of this type, by using both charge and light information. By exploiting muon capture in argon and scintillation light information to veto muon decay electrons, we also obtain muon neutrino identification efficiencies of about 50%, and muon antineutrino misidentification rates at the few percent level, for few-GeV neutrino interactions that are fully contained. We argue that the construction of large LAr detectors with sufficiently high light collection efficiencies is in principle possible.

  13. Integrated Operation of the G????-400 Gamma-Ray Telescope Scintillation Detector Systems

    NASA Astrophysics Data System (ADS)

    Runtso, Mikhail

    In this paper the question of integrated operation of scintillation detector systems AC (anticoincidence system) and SDC (scintillation detector system of calorimeter) in the G????-400 gamma-ray telescope is discussed. The main problem is the presence of so-called «backsplash current» (BSC) of particles from massive telescope calorimeter when detecting of very high-energy gamma-rays is provided. BSC is a low energy particle flux, moving up from the calorimeter and producing triggering of the AC detector, imitating detection of a charged particle. It is offered to record all events accompanied by BSC that should not result in to overload of the gamma-ray telescope in frequency of triggering. As an indicator to the number of BSC particles in the AC detector we offer the value of energy release in the C3 scintillation detector placing between two parts of the calorimeter (KK1 and KK2). Using mathematical simulation, the threshold on energy release in the C3 detector equal to 280 GeV was determined, at which the losses of gamma-quanta number in events with BSC do not exceed 10%. When detecting protons there are also events with BSC, which will be accompanied by exceeding of the indicated threshold of energy release in the ?3 detector for proton energies above 30 GeV. However, counting rate for such protons will not exceed 200 Hz, that is reasonable for the GAMMA-400 data acquisition system.

  14. SENTIRAD—An innovative personal radiation detector based on a scintillation detector and a silicon photomultiplier

    NASA Astrophysics Data System (ADS)

    Osovizky, A.; Ginzburg, D.; Manor, A.; Seif, R.; Ghelman, M.; Cohen-Zada, I.; Ellenbogen, M.; Bronfenmakher, V.; Pushkarsky, V.; Gonen, E.; Mazor, T.; Cohen, Y.

    2011-10-01

    The alarming personal radiation detector (PRD) is a device intended for Homeland Security (HLS) applications. This portable device is designed to be worn or carried by security personnel to detect photon-emitting radioactive materials for the purpose of crime prevention. PRD is required to meet the scope of specifications defined by various HLS standards for radiation detection. It is mandatory that the device be sensitive and simultaneously small, pocket-sized, of robust mechanical design and carriable on the user's body. To serve these specialized purposes and requirements, we developed the SENTIRAD, a new radiation detector designed to meet the performance criteria established for counterterrorist applications. SENTIRAD is the first commercially available PRD based on a CsI(Tl) scintillation crystal that is optically coupled with a silicon photomultiplier (SiPM) serving as a light sensor. The rapidly developing technology of SiPM, a multipixel semiconductor photodiode that operates in Geiger mode, has been thoroughly investigated in previous studies. This paper presents the design considerations, constraints and radiological performance relating to the SENTIRAD radiation sensor.

  15. Gamma-ray detector employing scintillators coupled to semiconductor drift photodetectors

    DOEpatents

    Iwanczyk, Jan S. (Los Angeles, CA); Patt, Bradley E. (Sherman Oaks, CA)

    2003-01-01

    Radiation detectors according to one embodiment of the invention are implemented using scintillators combined with a semiconductor drift photodetectors wherein the components are specifically constructed in terms of their geometry, dimensions, and arrangement so that the scintillator decay time and drift time in the photodetector pairs are matched in order to achieve a greater signal-to-noise ratio. The detectors may include electronics for amplification of electrical signals produced by the silicon drift photodetector, the amplification having a shaping time optimized with respect to the decay time of the scintillator and time spread of the signal in the silicon drift photodetector to substantially maximize the ratio of the signal to the electronic noise.

  16. Basic performance of a large area PET detector with a monolithic scintillator.

    PubMed

    Yoshida, Eiji; Inadama, Naoko; Osada, Hiroto; Kawai, Hideyuki; Nishikido, Fumihiko; Murayama, Hideo; Tsuda, Tomoaki; Yamaya, Taiga

    2011-07-01

    Conventionally, block detectors, which consist of a two-dimensionally segmented scintillator array with inserted reflectors, are often used for PET. On the other hand, PET detectors with a monolithic block have been investigated because they are expected to offer higher resolution than do segmented crystal arrays. However, previous reports focused on detectors dedicated as small-animal PET, and the thickness was not good enough to stop 511-keV radiation. We developed a PET detector that uses a large and thick monolithic LYSO and 64-channel PS-PMT. When the LYSO was covered with reflectors, the spatial resolution, which was 3 mm FWHM at the center, rapidly became worse at the edge. We eliminated the loss of spatial resolution by replacing the reflectors with black paper, but the light output was decreased. Therefore, we concluded that spatial resolution and light output were in a trade-off relationship due to the edge effect of scintillation light. PMID:21340540

  17. Wavelength-Shifting-Fiber Scintillation Detectors for Thermal Neutron Imaging at SNS

    SciTech Connect

    Clonts, Lloyd G [ORNL; Cooper, Ronald G [ORNL; Crow, Lowell [ORNL; Diawara, Yacouba [ORNL; Ellis, E Darren [ORNL; Funk, Loren L [ORNL; Hannan, Bruce W [ORNL; Hodges, Jason P [ORNL; Richards, John D [ORNL; Riedel, Richard A [ORNL; Wang, Cai-Lin [ORNL

    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.

  18. A Scintillator tile-fiber preshower detector for the CDF Central Calorimeter

    SciTech Connect

    S. Lami

    2004-08-12

    The front face of the CDF central calorimeter is being equipped with a new Preshower detector, based on scintillator tiles read out by WLS fibers. A light yield of about 40 pe/MIP at the tile exit was obtained, exceeding the design requirements.

  19. Monte Carlo modeling of fiber-scintillator flow-cell radiation detector geometry

    Microsoft Academic Search

    T. L. Rucker; H. H. Ross; G. K. Schweitzer

    1988-01-01

    A Monte Carlo computer calculation is described which models the geometric efficiency of a fiber-scintillator flow-cell radiation detector designed to detect radiolabeled compounds in liquid chromatography eluates. By using special mathematical techniques, an efficiency prediction with a precision of 1% is obtained after generating only 1000 random events. Good agreement is seen between predicted and experimental efficiency except for very

  20. ACE-CRIS Scintillating Optical Fiber Trajectory (SOFT) detector: a calibration at the NSCL

    Microsoft Academic Search

    Paul L. Hink; W. Robert Binns; J. Klarmann; M. A. Olevitch

    1996-01-01

    The scintillating optical fiber trajectory (SOFT) detector, which is the hodoscope for the cosmic ray isotope spectrometer (CRIS) on the NASA advanced composition explorer (ACE) satellite, was calibrated using 155 MeV\\/n He, Li, C, N, O, Ne, and Ar at the Michigan State University National Superconducting Cyclotron Laboratory (NSCL). The instrument consists of three hodoscope fiber planes and one trigger

  1. A Calibration of the ACE-CRIS Scintillating Optical Fiber Trajectory Detector at the MSU NSCL

    Microsoft Academic Search

    P. L. Hink; W. R. Binns; J. Klarmann; M. A. Olevitch

    1996-01-01

    The Scintillating Optical Fiber Trajectory (SOFT) detector, which is the hodoscope for the Cosmic Ray Isotope Spectrometer (CRIS) on the NASA Advanced Composition Explorer, was calibrated using 155 MeV\\/n He, Li, C, N, O, Ne, and Ar at the Michigan State University National Superconducting Cyclotron Laboratory (NSCL). The flight instrument consists of three hodoscope fiber planes and one trigger plane

  2. Monte Carlo simulation for the scintillating fibres tracking detector and its resolution evaluation

    Microsoft Academic Search

    C. D'Ambrosio; S. Qian

    1993-01-01

    For the scintillating fibres tracking detector (SFTD) [C. D'Ambrosio et al., Nucl. Instr. and Meth. A 322 (1992) 20] to be used as central tracker in a supercollider experiment, a Monte Carlo simulation has been performed to study its basic features. Charged particles with momenta up to 10 TeV\\/c have been tracked inside the detector at different polar angles in

  3. High voltage photodetector calibration for improved timing resolution with scintillation detectors for TOF-PET imaging

    Microsoft Academic Search

    Z. S. Davidson; R. I. Wiener; F. M. Newcomer; R. VanBerg; J. S. Karp

    2011-01-01

    The development of scintillators, photodetectors and electronics with excellent timing properties has made possible bench-top time-of-flight (TOF) measurements with sub 200 ps coincident timing resolution. In a light sharing configuration, losses in light collection result in degraded detector timing resolution. Photodetector uniformity in a light sharing configuration between many detectors is a significant limiting factor in the achievement of similar

  4. An activated charcoal-based, liquid scintillation-analyzed airborne Rn detector

    SciTech Connect

    Schroeder, M.C.; Vanags, U.; Hess, C.T.

    1989-07-01

    An inexpensive, easy-to-use detector for measuring airborne /sup 222/Rn based on /sup 222/Rn diffusion and absorption in activated charcoal is presented. The detector uses chemical extraction and liquid scintillation for measurement of the /sup 222/Rn concentration, is designed to be insensitive to temperature and humidity effects, and obtains sensitivity levels of 675 CPM (Bq L-1)-1 (25 CPM (pCi L-1)-1) at room temperature.

  5. The Effect of Neutron and Gamma Ray Cross Talk Between Plastic Scintillating Detectors

    SciTech Connect

    Pozzi, S.A.

    2000-11-06

    In this paper a method is developed, using higher order statistics, to identify the type and degree of neutron and gamma ray cross talk between detectors that are placed in proximity to one another. A set of measurements was performed using the Nuclear Materials Identification System (NMIS) to acquire the time-dependent bicovariance of the pulses in fast plastic scintillating detectors. These signatures were analyzed to infer the degree and type of false coincidences (cross talk) in relation to true coincidences.

  6. Neutron emission measurement at the HL-2A tokamak device with a liquid scintillation detector

    SciTech Connect

    Xie, Xufei; Chen, Zhongjing; Peng, Xingyu; Yuan, Xi; Zhang, Xing; Cui, Zhiqiang; Du, Tengfei; Hu, Zhimeng; Li, Tao; Fan, Tieshuan, E-mail: tsfan@pku.edu.cn; Chen, Jinxiang; Li, Xiangqing; Zhang, Guohui [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 Beijing (China); Gorini, Giuseppe [Dipartimento di Fisica ‘G. Occhialini’, Universita degli Studi di Milano Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); Yuan, Guoliang; Yang, Jinwei; Yang, Qingwei [Southwestern Institute of Physics, 610000 Chengdu (China)

    2014-10-15

    Neutron emission measurement at the HL-2A tokamak device with a liquid scintillation detector is described. The detector was placed at a location with little structure material in the field of view, and equipped with a gain monitoring system which could provide the possibility to evaluate the gain variation as well as to correct for the detector response. Time trace of the neutron emissivity was obtained and it was consistent with the result of a standard {sup 235}U fission chamber. During the plasma discharge the neutron yield could vary by about four orders of magnitude and the fluctuation of the detector gain was up to about 6%. Pulse height spectrum of the liquid scintillation detector was constructed and corrected with the aid of the gain monitoring system, and the correction was found to be essential for the assessment of the neutron energy spectrum. This successful measurement offered experience and confidence for the application of liquid scintillation detectors in the upcoming neutron camera system.

  7. Scintillator gamma-ray detectors with silicon photomultiplier readouts for high-energy astronomy

    NASA Astrophysics Data System (ADS)

    Bloser, Peter F.; Legere, Jason; Bancroft, Christopher; McConnell, Mark L.; Ryan, James M.; Schwadron, Nathan

    2013-09-01

    Space-based gamma-ray detectors for high-energy astronomy face strict constraints of mass, volume, and power, and must endure harsh operating environments. Scintillator materials have a long history of successful operation under these conditions, and new materials offer greatly improved performance in terms of efficiency, time response, and energy resolution. The use of scintillators in space remains constrained, however, by the mass, volume, and fragility of the associated light readout device, typically a vacuum photomultiplier tube (PMT). Recently developed silicon photomultipliers (SiPMs) offer gains and efficiencies similar to those of PMTs, but with greatly reduced mass and volume, high ruggedness, and no high-voltage requirements. We have therefore been investigating the use of SiPM readouts for scintillator gamma-ray detectors, with an emphasis on their suitability for space- and balloonbased instruments for high-energy astronomy. We present our most recent results, including spectroscopy measurements for lanthanum bromide scintillators with SiPM readouts, and pulse-shape discrimination using organic scintillators with SiPM readouts. We also describe potential applications of SiPM readouts to specific highenergy astronomy instrument concepts.

  8. A new columnar CsI(Tl) scintillator for iQID detectors

    NASA Astrophysics Data System (ADS)

    Han, Ling; Miller, Brian W.; Barber, H. Bradford; Nagarkar, Vivek V.; Furenlid, Lars R.

    2014-09-01

    A 1650 ?m thick columnar CsI(Tl) scintillator for upgrading iQID detectors, which is a high-resolution photon-counting gamma-ray and x-ray detector recently developed at the Center for Gamma-Ray Imaging (CGRI), has been studied in terms of sensitivity, spatial resolution and depth-of-interaction effects. To facilitate these studies, a new frame-parsing algorithm for processing raw event data is also proposed that has more degrees of freedom in data processing and can discriminate against a special kind of noise present in some low-cost intensifiers. The results show that in comparison with a 450 ?m-thickness columnar CsI(Tl) scintillator, the 1650 ?m thick CsI(Tl) scintillator provides more than twice the sensitivity at the expense of some spatial resolution degradation. The depth-of-interaction study also shows that event size and amplitude vary with scintillator thickness, which can assist in future detector simulations and 3D-interactionposition estimation.

  9. A region segmentation based algorithm for building a crystal position lookup table in a scintillation detector

    NASA Astrophysics Data System (ADS)

    Wang, Hai-Peng; Yun, Ming-Kai; Liu, Shuang-Quan; Fan, Xin; Cao, Xue-Xiang; Chai, Pei; Shan, Bao-Ci

    2015-03-01

    In a scintillation detector, scintillation crystals are typically made into a 2-dimensional modular array. The location of incident gamma-ray needs be calibrated due to spatial response nonlinearity. Generally, position histograms-the characteristic flood response of scintillation detectors-are used for position calibration. In this paper, a position calibration method based on a crystal position lookup table which maps the inaccurate location calculated by Anger logic to the exact hitting crystal position has been proposed. Firstly, the position histogram is preprocessed, such as noise reduction and image enhancement. Then the processed position histogram is segmented into disconnected regions, and crystal marking points are labeled by finding the centroids of regions. Finally, crystal boundaries are determined and the crystal position lookup table is generated. The scheme is evaluated by the whole-body positron emission tomography (PET) scanner and breast dedicated single photon emission computed tomography scanner developed by the Institute of High Energy Physics, Chinese Academy of Sciences. The results demonstrate that the algorithm is accurate, efficient, robust and applicable to any configurations of scintillation detector. Supported by National Natural Science Foundation of China (81101175) and XIE Jia-Lin Foundation of Institute of High Energy Physics (Y3546360U2)

  10. Simulation tool for optical design of PET detector modules including scintillator material and sensor array

    SciTech Connect

    Jatekos, B.; Erdei, G.; Lorincz, E. [Budapest Univ. of Technology and Economics, Dept. of Atomic Physics, Budafoki ut 8, H-1111 Budapest (Hungary)

    2011-07-01

    The appearance of single photon avalanche diodes (SPADs) in the field of PET detector modules made it necessary to apply more complex optical design methods to refine the performance of such assemblies. We developed a combined simulation tool that is capable to model complex detector structures including scintillation material, light guide, light collection optics and sensor, correctly taking into account the statistical behavior of emission of scintillation light and its absorbance in SPADs. As a validation we compared simulation results obtained by our software and another optical design program. Calculations were performed for a simple PET detector arrangement used for testing purposes. According to the results, deviation of center of gravity coordinates between the two simulations is 0.0195 mm, the average ratio of total counts 1.0052. We investigated the error resulting from finite sampling in wavelength space and we found that 20 nm pitch is sufficient for the simulation in case of the given spectral dependencies. (authors)

  11. Neutrinoless Double Beta Decay Sensitivity in Water-based Liquid Scintillator Detectors

    NASA Astrophysics Data System (ADS)

    Mastbaum, Andrew; Advanced Scintillator Detector Concept (ASDC) Team

    2015-04-01

    The recent development of Water-based Liquid Scintillators (WbLS) and high-resolution photosensors opens up new possibilities for large-scale detectors with sensitivity to a broad range of interesting physics. In particular, by optimizing the concentration of scintillator in a WbLS, it may be possible to achieve Water Cherenkov-like direction reconstruction with dramatically improved energy resolution. Studies by the ASDC interest group suggest that a single, large WbLS detector in a long-baseline beam could simultaneously achieve good sensitivity to the mass hierarchy; CP violation; several proton decay modes; solar, geo- and supernova neutrinos; and neutrino-less double-beta decay (0 ???). We present here a preliminary study of the 0 ??? sensitivity of such WbLS detectors.

  12. Searching for dark matter annihilation to monoenergetic neutrinos with liquid scintillation detectors

    NASA Astrophysics Data System (ADS)

    Kumar, J.; Sandick, P.

    2015-06-01

    We consider searches for dark matter annihilation to monoenergetic neutrinos in the core of the Sun. We find that liquid scintillation neutrino detectors have enhanced sensitivity to this class of dark matter models, due to the energy and angular resolution possible for electron neutrinos and antineutrinos that scatter via charged-current interactions. In particular we find that KamLAND, utilizing existing data, could provide better sensitivity to such models than any current direct detection experiment for mX lesssim 15 Gev. KamLAND's sensitivity is signal-limited, and future liquid scintillation or liquid argon detectors with similar energy and angular resolution, but with larger exposure, will provide significantly better sensitivity. These detectors may be particularly powerful probes of dark matter with mass Script O(10) GeV.

  13. Fast calibration of SPECT monolithic scintillation detectors using un-collimated sources

    NASA Astrophysics Data System (ADS)

    España, Samuel; Deprez, Karel; Van Holen, Roel; Vandenberghe, Stefaan

    2013-07-01

    Monolithic scintillation detectors for positron emission tomography and single-photon emission computed tomography (SPECT) imaging have many advantages over pixelated detectors. The use of monolithic crystals allows for reducing the scintillator cost per unit volume and increasing the sensitivity along with the energy and timing resolution of the detector. In addition, on thick detectors the depth-of-interaction can be determined without additional hardware. However, costly and complex calibration procedures have been proposed to achieve optimal detector performance for monolithic detectors. This hampers their use in commercial systems. There is thus, a need for simple calibration routines that can be performed on assembled systems. The main goal of this work is to develop a simplified calibration procedure based on acquired training data. In comparison with other methods that use training data acquired with beam sources attached to robotic stages, the proposed method uses a static un-collimated activity source with simple geometry acquiring in a reasonable time. Once the data are acquired, the calibration of the detector is accomplished in three steps: energy calibration based on the k-means clustering method, self-organization based on the self-organizing maps algorithm, and distortion correction based on the Monge-Kantorovich grid adaptation. The proposed calibration method was validated for 2D positioning using a SPECT detector. Similar results were obtained by comparison with an existing calibration method (maximum likelihood estimation). In conclusion, we proposed a novel calibration method for monolithic scintillation detectors that greatly simplifies their use with optimal performance in SPECT systems.

  14. Investigation of ZnO-Based Polycrystalline Ceramic Scintillators for Use as ?-Particle Detectors

    SciTech Connect

    Neal, John S [ORNL; DeVito, David M [ORNL; Armstrong, Beth L [ORNL; Hong, Mei [University of California; Kesanli, Banu [ORNL; Yang, Xiaocheng [West Virginia University; Giles, N. C. [West Virginia University; Howe, Jane Y [ORNL; Ramey, Joanne Oxendine [ORNL; Wisniewski, Dariusz J [ORNL; Wisniewski, Monica [Oak Ridge National Laboratory (ORNL); Munir, Zuhair [University of California; Boatner, Lynn A [ORNL

    2009-01-01

    ZnO-based scintillators are particularly well-suited for use as the associated particle detector in a deuterium-tritium (D-T) neutron generator. Application requirements include the exclusion of organic materials, outstanding timing resolution, and high radiation resistance. ZnO, ZnO:Ga, ZnO:In, ZnO:In,Li, and ZnO:Er,Li have demonstrated fast (sub-nanosecond) decay times with relatively low light yields. ZnO:Ga has been used in a powder form as the associated particle detector for a D-T neutron generator. Unfortunately, detectors using powders are difficult to assemble and the light yield from powders is less than satisfactory. Single crystal ZnO of sufficient size has only recently become available. New applications for D-T neutron generators require better timing resolution and higher count rates than are currently available with associated particle detectors using YAP:Ce as the scintillator. Recent work suggests that ZnO-based scintillators can provide alpha-particle-excited light yields comparable to YAP:Ce scintillators. ZnO-based polycrystalline ceramic scintillators offer the advantages of high light yield, ease of fabrication, low cost, and robust mechanical properties. Precursor powders used in these studies include ZnO and ZnO:Ga powders synthesized using solution phase, urea precipitation, and combustion synthesis techniques as well as ZnO powder from a commercial vendor. Precursor powders have been sintered using uniaxial hot pressing and spark plasma sintering techniques. Photoluminescence measurements have confirmed that, for most samples, the emissions from these sintered bodies consist primarily of slow, visible emissions rather than the desired, sub-nanosecond near-band-edge emissions. Subsequent hydrogen treatments have shown significant improvements in the luminescence characteristics of some ceramic bodies while other samples have shown no change in luminescence.

  15. Performance measurement of the scintillator with optical fiber detector for boron neutron capture therapy.

    PubMed

    Komeda, M; Kumada, H; Ishikawa, M; Nakamura, T; Yamamoto, K; Matsumura, A

    2009-07-01

    The thermal neutron flux can be easily measured in real time by using the scintillator with optical fiber (SOF) detector. However the irradiation damage under high-intensity neutron flux causes deterioration of the SOF detector due to radiation damage to the plastic scintillator in which (6)LiF is blended. After irradiating the SOF detector for 4 h (thermal neutron fluence is approximately 2.0 x 10(13)neutrons/cm(2)), the sensitivity of the SOF detector decreased by 3.0%. After irradiating the SOF detector for 2 months (thermal neutron fluence approximately 6.4 x 10(14)neutrons/cm(2)), the sensitivity was reduced to 42% of baseline. Supposing that the thermal neutron fluence is 2 x 10(12)neutrons/cm(2) on the surface of a patient in a BNCT treatment, the sensitivity of the SOF detector is reduced by approximately 0.3%. This report presents investigations on the deterioration of the SOF detector in irradiation experiments. PMID:19398347

  16. Scintillator Flow Modeling Borexino is capable of online scintillator purification while the detector is in opera-

    E-print Network

    volume. The loop mode efficiency will approach the batch mode efficiency in the limit where no mixing in a loop mode where the efficiency is reduced. Draining the Borexino detector is a major operation that would take several months and is not foreseen under normal operating conditions. #12;Chapter 6

  17. Realization of a small-size high resolution linear neutron scintillation detector

    SciTech Connect

    Engels, R.; Reinartz, R.; Reinhart, P.; Schelten, J. [Forschungszentrum Juelich GmbH (Germany)] [Forschungszentrum Juelich GmbH (Germany); Jansen, E.; Schaefer, W. [Univ. Bonn (Germany). Mineralogisches Inst.] [Univ. Bonn (Germany). Mineralogisches Inst.

    1998-06-01

    The spectrum of position sensitive neutron scintillation detectors, which have been developed and designed in the institute during the last decade, comprises several high resolution linear detectors. The design of the small size high resolution detector is based on a modified Anger technology using a linear array of 24 HAMAMATSU type R1770 rectangular photomultipliers and a 1 mm {sup 6}Li glass scintillator. The sensitive detector area is 200 x 20 mm{sup 2} and the spatial resolution is 1.2 mm. The neutron sensitivity at 1{angstrom} is about 65% and the residual gamma sensitivity is less than 10{sup {minus}4} and the maximum count rate is about 100 kHz. The detector is linked to a highly flexible PC-based data acquisition system with 12 bit position and 16 bit time resolution. The stand alone detector and data acquisition system is aimed preferably at pulsed sources performing high resolution angle-dispersive time-of-flight experiments.

  18. Scintillating-fiber imaging detector for 14-MeV neutrons

    SciTech Connect

    Ress, D.; Lerche, R.A.; Ellis, R.J.; Heaton, G.W.; Nelson, M.B.; Mant, G. [Lawrence Livermore National Lab., CA (United States); Lehr, D.E. [Stanford Univ., CA (United States). Physics Dept.

    1994-07-25

    The authors have created a detector to image the neutrons emitted by imploded inertial-confinement fusion targets. The 14-MeV neutrons, which are produced by deuterium-tritium fusion events in the target, pass through an aperture to create an image on the detector. The neutron radiation is converted to blue light (430 nm) with a 20-cm-square array of plastic scintillating fibers. Each fiber is 10-cm long with a 1-mm-square cross section; approximately 35-thousand fibers make up the array. The resulting blue-light image is reduced and amplified by a sequence of fiber-optic tapers and image intensifiers, then acquired by a CCD camera. The fiber-optic readout system was tested optically for overall throughput the resolution. The authors plan to characterize the scintillator array reusing an ion-beam neutron source as well as DT-fusion neutrons emitted by inertial confinement targets. Characterization experiments will measure the light-production efficiency, spatial resolution, and neutron scattering within the detector. Several neutron images of laser-fusion targets have been obtained with the detector. Several neutron images of laser-fusion targets have been obtained with the detector. They describe the detector and their characterization methods, present characterization results, and give examples of the neutron images.

  19. A scintillating bar tracking detector for the ASACUSA - "trap group" experiment at the CERN AD

    NASA Astrophysics Data System (ADS)

    Mascagna, V.; Bolognini, D.; Corradini, M.; Leali, M.; Lietti, D.; Lodi Rizzini, E.; Prest, M.; Stoppani, L.; Vallazza, E.; Venturelli, L.; Zurlo, N.

    2010-04-01

    The ASACUSA trap group aim is the production and the study of antihydrogen at the CERN AD (Antiproton Decelerator). After the end of 2007, when the first results were obtained, it was evident that to improve the trapping efficiency of the antiprotons, their annihilation position within the electromagnetic trap had to be reconstructed. A scintillating bar detector, capable of tracking the charged pions produced in the annihilations, has been built for this purpose. The detector consists in 4 XY-modules, made of 96 cm long scintillating bars readout by multianode photomultipliers. The anode outputs are managed by dedicated electronics boards equipped with VA64TAP2.1 (Gamma Medica, Ideas) ASICs and ALTERA FPGAs. This paper describes the design and the commissioning of the 4 modules in 2008 and some preliminary results of the 2009 data taking.

  20. Development of the Fast Scintillation Detector with Programmable High Voltage Adjustment Suitable for Mössbauer Spectroscopy

    NASA Astrophysics Data System (ADS)

    Prochazka, R.; Pechousek, J.; Frydrych, J.

    2010-07-01

    This work is focused on a development of a compact fast scintillation detector suitable for Mössbauer spectroscopy (low energy X-ray/?-ray detection) where high counting rates are inevitable. Optimization of this part was necessary for a reliable function, better time resolution and to avoid a detector pulses pile-up effect. The pile-up effect decreases the measurement performance, significantly depends on the source activity and also on the pulse duration. Our new detection unit includes a fast scintillation crystal YAP:Ce, an R6095 photomultiplier tube, a high voltage power supply socket C9028-01 assembly, an AD5252 digital potentiometer with an I2C interface and an AD8000 ultra fast operation preamplifier. The main advantages of this solution lie in a short pulse duration (less than 200 ns), stable operation for high activities, programmable gain of the high voltage supply and compact design in the aluminum housing.

  1. Development of the Fast Scintillation Detector with Programmable High Voltage Adjustment Suitable for Moessbauer Spectroscopy

    SciTech Connect

    Prochazka, R.; Frydrych, J. [Center for Nanomaterial Research, Faculty of Science Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Pechousek, J. [Center for Nanomaterial Research, Faculty of Science Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Experimental Physics, Faculty of Science, 17. listopadu 1192/12, 771 46 Olomouc (Czech Republic)

    2010-07-13

    This work is focused on a development of a compact fast scintillation detector suitable for Moessbauer spectroscopy (low energy X-ray/{gamma}-ray detection) where high counting rates are inevitable. Optimization of this part was necessary for a reliable function, better time resolution and to avoid a detector pulses pile-up effect. The pile-up effect decreases the measurement performance, significantly depends on the source activity and also on the pulse duration. Our new detection unit includes a fast scintillation crystal YAP:Ce, an R6095 photomultiplier tube, a high voltage power supply socket C9028-01 assembly, an AD5252 digital potentiometer with an I2C interface and an AD8000 ultra fast operation preamplifier. The main advantages of this solution lie in a short pulse duration (less than 200 ns), stable operation for high activities, programmable gain of the high voltage supply and compact design in the aluminum housing.

  2. MCNPX--PoliMi Variance Reduction Techniques for Simulating Neutron Scintillation Detector Response

    NASA Astrophysics Data System (ADS)

    Prasad, Shikha

    Scintillation detectors have emerged as a viable He-3 replacement technology in the field of nuclear nonproliferation and safeguards. The scintillation light produced in the detectors is dependent on the energy deposited and the nucleus with which the interaction occurs. For neutrons interacting with hydrogen in organic liquid scintillation detectors, the energy-to-light conversion process is nonlinear. MCNPX-PoliMi is a Monte Carlo Code that has been used for simulating this detailed scintillation physics; however, until now, simulations have only been done in analog mode. Analog Monte Carlo simulations can take long times to run, especially in the presence of shielding and large source-detector distances, as in the case of typical nonproliferation problems. In this thesis, two nonanalog approaches to speed up MCNPX-PoliMi simulations of neutron scintillation detector response have been studied. In the first approach, a response matrix method (RMM) is used to efficiently calculate neutron pulse height distributions (PHDs). This method combines the neutron current incident on the detector face with an MCNPX-PoliMi-calculated response matrix to generate PHDs. The PHD calculations and their associated uncertainty are compared for a polyethylene-shielded and lead-shielded Cf-252 source for three different techniques: fully analog MCNPX-PoliMi, the RMM, and the RMM with source biasing. The RMM with source biasing reduces computation time or increases the figure-of-merit on an average by a factor of 600 for polyethylene and 300 for lead shielding (when compared to the fully analog calculation). The simulated neutron PHDs show good agreement with the laboratory measurements, thereby validating the RMM. In the second approach, MCNPX-PoliMi simulations are performed with the aid of variance reduction techniques. This is done by separating the analog and nonanalog components of the simulations. Inside the detector region, where scintillation light is produced, no variance reduction techniques are used. Outside the detector region, where there may be thick shields or large source-detector distances, certain standard variance reduction techniques are used. Tally mechanisms are developed for PHDs, time-of-flight curves, and cross-correlations. Three laboratory measurements (bare, lead-shielded, and polyethylene shielded) are performed with a Cf-252 source to validate the nonanalog MCNPX-PoliMi cross-correlation simulations. For the bare cross-correlation case, the nonanalog simulation speedup was a factor of 3.4; for the lead-shielded case, the speedup was a factor of 16; and for the polyethylene-shielded case, the speedup was a factor of 2.6. The agreement of simulations with laboratory measurements was good. In summary, this thesis demonstrates that known variance reduction techniques, when properly applied to nonlinear scintillation detector response problems, can significantly increase the figure-of-merit (sometimes by 2 or 3 orders of magnitude). This can yield major reductions in computation times and analyses for important homeland security problems.

  3. Limits on WIMP dark matter using scintillating CaWO 4 cryogenic detectors with active background suppression

    Microsoft Academic Search

    G. Angloher; C. Bucci; P. Christ; C. Cozzini; F. von Feilitzsch; D. Hauff; S. Henry; Th. Jagemann; J. Jochum; H. Kraus; B. Majorovits; J. Ninkovic; F. Petricca; W. Potzel; F. Probst; Y. Ramachers; M. Razeti; W. Rau; W. Seidel; M. Stark; L. Stodolsky; A. J. B. Tolhurst; W. Westphal; H. Wulandari

    2005-01-01

    We present first significant limits on WIMP dark matter by the phonon-light technique, where combined phonon and light signals from a scintillating cryogenic detector are used. Data from early 2004 with two 300g CRESST-II prototype detector modules are presented, with a net exposure of 20.5kg days. The modules consist of a CaWO4 scintillating “target” crystal and a smaller cryogenic light

  4. Measurements and elimination of Cherenkov light in fiber-optic scintillating detector for electron beam therapy dosimetry

    Microsoft Academic Search

    Bongsoo Lee; Kyoung Won Jang; Dong Hyun Cho; Wook Jae Yoo; Gye-Rae Tack; Soon-Cheol Chung; Sin Kim; Hyosung Cho

    2007-01-01

    In this study, a miniature fiber-optic radiation detector has been developed using a water-equivalent organic scintillator for electron beam therapy dosimetry. Usually, two kinds of light signals such as fluorescent and Cherenkov lights are generated in a fiber-optic radiation detector when a high-energy electron beam is irradiated. The fluorescent light signal is produced in the scintillator and is transmitted through

  5. Development of a Gamma-ray Burst Detector Based on the Silicon Drift Detector Array and Scintillators

    SciTech Connect

    Yamaoka, Kazutaka; Arai, Yusuke; Doshida, Takaaki; Watanabe, Tsuyoshi; Tsutsui, Akihito; Asano, Satoshi; Yoshida, Kotaro; Yoshida, Atsumasa [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 229-8558 (Japan); Pahlke, Andreas [KETEK GmbH, Hofer Strasse 3, 81737 Munchen (Germany); Ikeda, Hirokazu; Takahashi, Tadayuki [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Mori, Kunishiro [Clear Pulse Ltd, 6-25-17 Chuoh, Ohta-ku, Tokyo 143-0024 (Japan); Kato, Hiroshi [Makishima Cosmic Radiation Laboratory, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2008-05-22

    We propose a gamma-ray burst (GRB) detector combining the silicon drift detector (SDD) array and scintillators with broadband X-ray and gamma-ray coverage (0.5-1000 keV or more), high energy resolution (2-10%) and high time resolution ({approx}{mu}s) in space. To realize such compact high-performance detector without photomultiplier tubes, we constructed proto-type model using KETEK SDD with a detection area of 1 cm{sup 2} and BGO crystal. The detector shows a very good performance. Obtained FWHM energy resolution was 191 eV at 5.9 keV in the SDD, while 6.5 % at 662 keV in the BGO at -30 deg. C. Evaluation of the 7 channel SDD array and development of analog ASIC for its readout are also presented.

  6. Development of a thermal scintillating detector for double beta decay of 48Ca

    Microsoft Academic Search

    A. Alessandrello; V. Bashkirov; C. Brofferio; D. V. Camin; O. Cremonesi; E. Fiorini; G. Gervasio; A. Giuliani; M. Pavan; G. L. Pessina; E. Previtali; L. Zanotti

    1992-01-01

    Among double beta candidates 48Ca stands out for its 4.271 MeV transition energy, well above most of the contribution of natural gamma and beta radioactivity, but extremely near to the energy released in the alpha decay of 238U (4.274 MeV including nucleus recoil). A CaF2(Eu) detector with both thermal pulse and scintillation light readout would give very good discrimination against

  7. Determination of neutrino incoming direction in the CHOOZ experiment and Supernova explosion location by scintillator detectors

    Microsoft Academic Search

    M. Apollonio; A. Baldini; C. Bemporad; E. Caffau; F. Cei; Y. Declais; H. de Kerret; B. Dieterle; A. Etenko; L. Foresti; J. George; G. Giannini; M. Grassi; Y. Kozlov; W. Kropp; D. Kryn; M. Laiman; B. Lefievre; I. Machulin; A. Martemyanov; V. Martemyanov; L. Mikaelyan; D. Nicolo; M. Obolensky; R. Pazzi; G. Pieri; L. Price; S. Riley; R. Reeder; A. Sabelnikov; G. Santin; M. Skorokhvatov; H. Sobel; J. Steele; R. Steinberg; S. Sukhotin; S. Tomshaw; D. Veron; V. Vyrodov

    1999-01-01

    The CHOOZ experiment measured the antineutrino flux at a distance of about 1\\u000aKm from two nuclear reactors in order to detect possible neutrino oscillations\\u000awith squared mass differences as low as 10**-3 eV**2 for full mixing. We show\\u000athat the data analysis of the electron antineutrino events, collected by our\\u000aliquid scintillation detector, locates the antineutrino source within a

  8. Gamma-Ray Spectroscopy With LaBr :Ce Scintillator Readout by a Silicon Drift Detector

    Microsoft Academic Search

    C. Fiorini; A. Gola; M. Zanchi; A. Longoni; P. Lechner; H. Soltau; L. Struder

    2006-01-01

    In this paper, the authors propose a gamma-ray spectrometer based on a LaBr3 :Ce scintillator coupled to a silicon drift detector (SDD). The SDD is a photodetector characterized by a very low noise thanks to the low value of output capacitance independent from the active area. With respect to a PMT, the SDD offers a higher quantum efficiency which reduces

  9. Performance results for scintillation detectors for high temperature environments including MWD

    Microsoft Academic Search

    R. Dayton; M. Mayhugh; M. Papp; P. Parkhurst; R. Schreiner

    1988-01-01

    Sheet reflectors and elastomeric potting materials have become available for packaging NaI(T1) scintillation detectors. As a mechanical element of the system, these materials offer substantial advantages over the more traditional packed powders. In oil well applications, compatibility of the materials with NaI(T1) at high temperature presents a challenge. Specially treated systems are compatible with NaI(T1) to at least 200°C. Performance

  10. Assessment of the setup dependence of detector response functions for mega-voltage linear accelerators

    SciTech Connect

    Fox, Christopher; Simon, Tom; Simon, Bill; Dempsey, James F.; Kahler, Darren; Palta, Jatinder R.; Liu Chihray; Yan Guanghua [Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 and Department of Radiation Oncology, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); NRE, 202 Nuclear Science Building, University of Florida, P.O. Box 118300, Gainesville, Florida 32611-8300 and Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 (United States); Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 (United States); ViewRay Inc., 2 Thermo Fisher Way, Oakwood Village, Ohio 44146 (United States); Department of Radiation Oncology, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States)

    2010-02-15

    Purpose: Accurate modeling of beam profiles is important for precise treatment planning dosimetry. Calculated beam profiles need to precisely replicate profiles measured during machine commissioning. Finite detector size introduces perturbations into the measured profiles, which, in turn, impact the resulting modeled profiles. The authors investigate a method for extracting the unperturbed beam profiles from those measured during linear accelerator commissioning. Methods: In-plane and cross-plane data were collected for an Elekta Synergy linac at 6 MV using ionization chambers of volume 0.01, 0.04, 0.13, and 0.65 cm{sup 3} and a diode of surface area 0.64 mm{sup 2}. The detectors were orientated with the stem perpendicular to the beam and pointing away from the gantry. Profiles were measured for a 10x10 cm{sup 2} field at depths ranging from 0.8 to 25.0 cm and SSDs from 90 to 110 cm. Shaping parameters of a Gaussian response function were obtained relative to the Edge detector. The Gaussian function was deconvolved from the measured ionization chamber data. The Edge detector profile was taken as an approximation to the true profile, to which deconvolved data were compared. Data were also collected with CC13 and Edge detectors for additional fields and energies on an Elekta Synergy, Varian Trilogy, and Siemens Oncor linear accelerator and response functions obtained. Response functions were compared as a function of depth, SSD, and detector scan direction. Variations in the shaping parameter were introduced and the effect on the resulting deconvolution profiles assessed. Results: Up to 10% setup dependence in the Gaussian shaping parameter occurred, for each detector for a particular plane. This translated to less than a {+-}0.7 mm variation in the 80%-20% penumbral width. For large volume ionization chambers such as the FC65 Farmer type, where the cavity length to diameter ratio is far from 1, the scan direction produced up to a 40% difference in the shaping parameter between in-plane and cross-plane measurements. This is primarily due to the directional difference in penumbral width measured by the FC65 chamber, which can more than double in profiles obtained with the detector stem parallel compared to perpendicular to the scan direction. For the more symmetric CC13 chamber the variation was only 3% between in-plane and cross-plane measurements. Conclusions: The authors have shown that the detector response varies with detector type, depth, SSD, and detector scan direction. In-plane vs cross-plane scanning can require calculation of a direction dependent response function. The effect of a 10% overall variation in the response function, for an ionization chamber, translates to a small deviation in the penumbra from that of the Edge detector measured profile when deconvolved. Due to the uncertainties introduced by deconvolution the Edge detector would be preferable in obtaining an approximation of the true profile, particularly for field sizes where the energy dependence of the diode can be neglected. However, an averaged response function could be utilized to provide a good approximation of the true profile for large ionization chambers and for larger fields for which diode detectors are not recommended.

  11. Scintillator based detector for fast-ion losses induced by magnetohydrodynamic instabilities in the ASDEX upgrade tokamak

    SciTech Connect

    Garcia-Munoz, M.; Fahrbach, H.-U.; Zohm, H. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association Boltzmannstr. 2, D-85748 Garching (Germany); Collaboration: ASDEX Upgrade Team

    2009-05-15

    A scintillator based detector for fast-ion losses has been designed and installed on the ASDEX upgrade (AUG) tokamak [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)]. The detector resolves in time the energy and pitch angle of fast-ion losses induced by magnetohydrodynamics (MHD) fluctuations. The use of a novel scintillator material with a very short decay time and high quantum efficiency allows to identify the MHD fluctuations responsible for the ion losses through Fourier analysis. A Faraday cup (secondary scintillator plate) has been embedded behind the scintillator plate for an absolute calibration of the detector. The detector is mounted on a manipulator to vary its radial position with respect to the plasma. A thermocouple on the inner side of the graphite protection enables the safety search for the most adequate radial position. To align the scintillator light pattern with the light detectors a system composed by a lens and a vacuum-compatible halogen lamp has been allocated within the detector head. In this paper, the design of the scintillator probe, as well as the new technique used to analyze the data through spectrograms will be described. A last section is devoted to discuss the diagnosis prospects of this method for ITER [M. Shimada et al., Nucl. Fusion 47, S1 (2007)].

  12. Advances in Inorganic Scintillation Detectors for Geophysical Applications

    SciTech Connect

    Julie L. Champlin; Carlos M. Grodsinsky; William D. Sekela

    1998-12-31

    The ability to distinguish between geological formations and the change from one formation to another is crucial to the oil exploration and well logging industry. These changes are distinguished by the use of gamma-ray measurements, which detect the radioactive isotope combinations of potassium, thorium, and uranium present in the rock and fluid of these geological formations. A gamma radiation detector consisting of a sodium iodide crystal optically coupled to a photomultiplier tube is used for making these measurements. Because of the harsh environment seen while down hole, these detectors must be rugged in order to survive and perform under the conditions of extreme temperature, shock, and vibration. The two main geophysical applications designed for are wireline and measurement-while-drilling (MWD) environments. Three major product designs that fall under these environmental survival and performance criteria are discussed.

  13. Neural networks as first level triggers in scintillating fiber detectors

    SciTech Connect

    Orgeron, J.A.

    1993-01-01

    Trained feed-forward neural networks have been shown to have the inherent capability of providing a novel approach to performing extremely fast pattern recognition that can be incorporated into first-level triggers for particle detectors at high energy colliders. In this specific case, an extensive Monte Carlo software package specifically adapted for the proposed Solenoidal Detector Collaboration (SDC) detector at the Superconducting Super Collider (SSC) was used to simulate the expected high energy physics processes and detect the generated particles in order to obtain the most realistic data for training and testing of the networks. Computational facilities at both UTD and at the SSC Laboratory were used to train and test the accuracy and efficiency of these novel triggering schemes. Results obtained show that a neural network first-level trigger, with its inherent capacity for pattern recognition, has the ability to provide the triggering performance equal the currently proposed (combinatorial logic) trigger at design luminosity and outperform it as luminosities are increased to ten times the design level by providing false trigger rates a full order of magnitude lower.

  14. Observations on the background spectra of four LaCl 3 Ce scintillation detectors.

    PubMed

    Hartwell, J K; Gehrke, R J

    2005-08-01

    Our laboratory has purchased four LaCl (3)(Ce) scintillation crystals over the course of the last year for evaluation as part of an environmental management research and development project. In addition to the expected content of naturally radioactive (138)La, we have found that all four of these detectors are contaminated to various degrees with alpha particle emitting nuclides that we have determined to be (227)Ac and its daughters. The impact of these radionuclides on the background spectra and, thus, on the detection sensitivity of these detectors is presented and discussed. PMID:15894485

  15. Standardization method of ²²Na using two NaI(Tl) scintillation detectors.

    PubMed

    Sato, Y; Yamada, T; Hasegawa, T

    2014-05-01

    A new standardization method for a sealed (22)Na point source was developed utilizing two NaI(Tl) scintillation detectors. In the proposed method, the count rates of annihilation radiation, gamma rays, their coincidence sum, and the coincidences between the two detectors are used. The equations from which the source activity can be deduced are derived in this work. A series of EGS-5 Monte Carlo calculations were conducted to test the validity of the expressions. The calculated activity agreed within approximately 1 percent with the literature data used as input in the simulations. PMID:24411317

  16. A New scintillator tile / fiber preshower detector for the CDF central calorimeter

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.; Artikov, A.; Bromberg, C.; Budagov, J.; Byrum, K.; Chang, S.; Chlachidze, G.; Goulianos, K.; Huston, J.; Iori, M.; Kim, M.; Kuhlmann,; Lami, S.; Lindgren, M.; Lytken, E.; Miller, R.; Nodulman, L.; Pauletta, G.; Penzo, A.; Proudfoot, J.; Roser, R.; /Argonne /Dubna, JINR /Fermilab /Kyungpook Natl. U. /Michigan

    2004-11-01

    A detector designed to measure early particle showers has been installed in front of the central CDF calorimeter at the Tevatron. This new preshower detector is based on scintillator tiles coupled to wavelength-shifting fibers read out by multianode photomultipliers and has a total of 3,072 readout channels. The replacement of the old gas detector was required due to an expected increase in instantaneous luminosity of the Tevatron collider in the next few years. Calorimeter coverage, jet energy resolution, and electron and photon identification are among the expected improvements. The final detector design, together with the R&D studies that led to the choice of scintillator and fiber, mechanical assembly, and quality control are presented. The detector was installed in the fall 2004 Tevatron shutdown and is expected to start collecting colliding beam data by the end of 2004. First measurements indicate a light yield of 12 photoelectrons/MIP, a more than two-fold increase over the design goals.

  17. Measurement of 238U muonic x-rays with a germanium detector setup

    SciTech Connect

    Esch, Ernst I [Los Alamos National Laboratory; Jason, Andrew [Los Alamos National Laboratory; Miyadera, Haruo [Los Alamos National Laboratory; Hoteling, Nathan J [Los Alamos National Laboratory; Heffner, Robert H [Los Alamos National Laboratory; Adelmann, Andreas [PAUL SCHERRER INSTITUT; Stocki, Trevor [HEALTH CANADA; Mitchell, Lee [NAVAL RESEARCH LAB

    2009-01-01

    In the field of nuclear non-proliferation muon interactions with materials are of great interest. This paper describes an experiment conducted at the Paul Scherrer Institut (PSI) in Switzerland where a muon beam is stopped in a uranium target. The muons produce characteristic muonic x-rays. Muons will penetrate shielding easily and the produced characteristic x-rays can be used for positive isotope identification. Furthermore, the x-rays for uranium isotopes lie in the energy range of 6-7 MeV, which allows them to have an almost optimal mean free path in heavy shielding such as lead or steel. A measurement was conducted at PSI to prove the feasibility of detecting muonic x-rays from a large sample of depleted uranium (several kilograms) with a germanium detector. In this paper, the experimental setup and analysis of the measurement itself is presented.

  18. Near midplane scintillator-based fast ion loss detector on DIII-D.

    PubMed

    Chen, X; Fisher, R K; Pace, D C; García-Muñoz, M; Chavez, J A; Heidbrink, W W; Van Zeeland, M A

    2012-10-01

    A new scintillator-based fast-ion loss detector (FILD) installed near the outer midplane of the plasma has been commissioned on DIII-D. This detector successfully measures coherent fast ion losses produced by fast-ion driven instabilities (?500 kHz). Combined with the first FILD at ?45° below the outer midplane [R. K. Fisher, et al., Rev. Sci. Instrum. 81, 10D307 (2010)], the two-detector system measures poloidal variation of losses. The phase space sensitivity of the new detector (gyroradius r(L) ? [1.5-8] cm and pitch angle ? ? [35°-85°]) is calibrated using neutral beam first orbit loss measurements. Since fast ion losses are localized poloidally, having two FILDs at different poloidal locations allows for the study of losses over a wider range of plasma shapes and types of loss orbits. PMID:23126881

  19. High spatial resolution radiation detectors based on hydrogenated amorphous silicon and scintillator

    SciTech Connect

    Jing, T [Univ. of California, Berkeley, CA (United States). Dept. of Engineering-Nuclear Engineering

    1995-05-01

    Hydrogenated amorphous silicon (a-Si:H) as a large-area thin film semiconductor with ease of doping and low-cost fabrication capability has given a new impetus to the field of imaging sensors; its high radiation resistance also makes it a good material for radiation detectors. In addition, large-area microelectronics based on a-Si:H or polysilicon can be made with full integration of peripheral circuits, including readout switches and shift registers on the same substrate. Thin a-Si:H p-i-n photodiodes coupled to suitable scintillators are shown to be suitable for detecting charged particles, electrons, and X-rays. The response speed of CsI/a-Si:H diode combinations to individual particulate radiation is limited by the scintillation light decay since the charge collection time of the diode is very short (< 10ns). The reverse current of the detector is analyzed in term of contact injection, thermal generation, field enhanced emission (Poole-Frenkel effect), and edge leakage. A good collection efficiency for a diode is obtained by optimizing the p layer of the diode thickness and composition. The CsI(Tl) scintillator coupled to an a-Si:H photodiode detector shows a capability for detecting minimum ionizing particles with S/N {approximately}20. In such an arrangement a p-i-n diode is operated in a photovoltaic mode (reverse bias). In addition, a p-i-n diode can also work as a photoconductor under forward bias and produces a gain yield of 3--8 for shaping times of 1 {micro}s. The mechanism of the formation of structured CsI scintillator layers is analyzed. Initial nucleation in the deposited layer is sensitive to the type of substrate medium, with imperfections generally catalyzing nucleation. Therefore, the microgeometry of a patterned substrate has a significant effect on the structure of the CsI growth.

  20. Simulation of the Scintillator Geometry in the Electromagnetic Calorimeter in the CLAS12 Detector

    NASA Astrophysics Data System (ADS)

    Sherman, Keegan; Gilfoyle, Gerard

    2012-10-01

    We have modified the geometry of the electromagnetic calorimeter (EC) in a simulation of the CLAS12 detector at Jefferson Lab (JLab). The goal of JLab is to understand how quarks and gluons form nucleons and nuclei. It is being upgraded with a higher energy beam and new detectors including CLAS12 in Hall B. To prepare for CLAS12's operation, we use the code gemc that is based on Geant4 to simulate particle tracks. The EC is one of the CLAS12 components and it is used to measure the energy and position of charged and neutral particles. It is composed of alternating layers of lead and scintillating plastic. Each layer of scintillator is, in turn, composed of 36 parallel strips that form a triangle about 4.7 m on a side. Adjacent layers are rotated 120 degrees so the crossed strips can be used to determine the position of a hit. In the past the scintillators have been defined as a large slab instead of stips to reduce computation time. We have redefined them as the more realistic strips in gemc. Using the UNIX ``time'' command we observe about a 5% increase in CPU time in the EC simulation. To test the effect on the interactive graphics in gemc we use glxgears and see about a 25% decrease in frame rate.

  1. Development of a fast radiation detector based on barium fluoride scintillation crystal.

    PubMed

    Han, Hetong; Zhang, Zichuan; Weng, Xiufeng; Liu, Junhong; Guan, Xingyin; Zhang, Kan; Li, Gang

    2013-07-01

    Barium fluoride (BaF2) is an inorganic scintillation material used for the detection of X?gamma radiation due to its relatively high density, equivalent atomic number, radiation hardness, and high luminescence. BaF2 has a potential capacity to be used in gamma ray timing experiments due to the prompt decay emission components. It is known that the light output from BaF2 has three decay components: two prompt of those at approximately 195 nm and 220 nm with a decay constant around 600-800 ps and a more intense, slow component at approximately 310 nm with a decay constant around 630 ns which hinders fast timing experiments. We report here the development of a fast radiation detector based on a BaF2 scintillation crystal employing a special optical filter device, a multiple reflection multi-path ultraviolet region short-wavelength pass light guides (MRMP-short pass filter) by using selective reflection technique, for which the intensity of the slow component is reduced to less than 1%. The methods used for this study provide a novel way to design radiation detector by utilizing scintillation crystal with several emission bands. PMID:23902059

  2. Development of a fast radiation detector based on barium fluoride scintillation crystal

    SciTech Connect

    Han, Hetong [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China) [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China); School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China); Zhang, Zichuan; Weng, Xiufeng; Liu, Junhong; Zhang, Kan; Li, Gang [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China)] [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China); Guan, Xingyin [School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China)] [School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China)

    2013-07-15

    Barium fluoride (BaF{sub 2}) is an inorganic scintillation material used for the detection of X/gamma radiation due to its relatively high density, equivalent atomic number, radiation hardness, and high luminescence. BaF{sub 2} has a potential capacity to be used in gamma ray timing experiments due to the prompt decay emission components. It is known that the light output from BaF{sub 2} has three decay components: two prompt of those at approximately 195 nm and 220 nm with a decay constant around 600-800 ps and a more intense, slow component at approximately 310 nm with a decay constant around 630 ns which hinders fast timing experiments. We report here the development of a fast radiation detector based on a BaF{sub 2} scintillation crystal employing a special optical filter device, a multiple reflection multi-path ultraviolet region short-wavelength pass light guides (MRMP-short pass filter) by using selective reflection technique, for which the intensity of the slow component is reduced to less than 1%. The methods used for this study provide a novel way to design radiation detector by utilizing scintillation crystal with several emission bands.

  3. Advances in the growth of alkaline-earth halide single crystals for scintillator detectors

    SciTech Connect

    Boatner, Lynn A [ORNL; Ramey, Joanne Oxendine [ORNL; Kolopus, James A [ORNL; Neal, John S [ORNL; Cherepy, Nerine [Lawrence Livermore National Laboratory (LLNL); Payne, Stephen A. [Lawrence Livermore National Laboratory (LLNL); Beck, P [Lawrence Livermore National Laboratory (LLNL); Burger, Arnold [Fisk University, Nashville; Rowe, E [Fisk University, Nashville; Bhattacharya, P. [Fisk University, Nashville

    2014-01-01

    Alkaline-earth scintillators such as strontium iodide and other alkaline-earth halides activated with divalent europium represent some of the most efficient and highest energy resolution scintillators for use as gamma-ray detectors in a wide range of applications. These applications include the areas of nuclear nonproliferation, homeland security, the detection of undeclared nuclear material, nuclear physics and materials science, medical diagnostics, space physics, high energy physics, and radiation monitoring systems for first responders, police, and fire/rescue personnel. Recent advances in the growth of large single crystals of these scintillator materials hold the promise of higher crystal yields and significantly lower detector production costs. In the present work, we describe new processing protocols that, when combined with our molten salt filtration methods, have led to advances in achieving a significant reduction of cracking effects during the growth of single crystals of SrI2:Eu2+. In particular, we have found that extended pumping on the molten crystal-growth charge under vacuum for time periods extending up to 48 hours is generally beneficial in compensating for variations in the alkaline-earth halide purity and stoichiometry of the materials as initially supplied by commercial sources. These melt-pumping and processing techniques are now being applied to the purification of CaI2:Eu2+ and some mixed-anion europium-doped alkaline-earth halides prior to single-crystal growth by means of the vertical Bridgman technique. The results of initial studies of the effects of aliovalent doping of SrI2:Eu2+ on the scintillation characteristics of this material are also described.

  4. Scintillator Pad Detector: Very Front End Electronics. Design and Pre-Series

    SciTech Connect

    Luengo, S.; Riera, J.; Tortella, S.; Vilasis-Cardona, X. [Dept. Electronica, Enginyeria i Arquitectura La Salle, Universitat Ramon Llull, Barcelona (Spain); Gascon, D.; Comerma, A.; Garrido, L. [Dept. Estructura i Constituents de la Materia, Universitat de Barcelona, Barcelona (Spain)

    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.

  5. Can scintillation detectors with low spectral resolution accurately determine radionuclides content of building materials?

    PubMed

    Kovler, K; Prilutskiy, Z; Antropov, S; Antropova, N; Bozhko, V; Alfassi, Z B; Lavi, N

    2013-07-01

    The current paper makes an attempt to check whether the scintillation NaI(Tl) detectors, in spite of their poor energy resolution, can determine accurately the content of NORM in building materials. The activity concentrations of natural radionuclides were measured using two types of detectors: (a) NaI(Tl) spectrometer equipped with the special software based on the matrix method of least squares, and (b) high-purity germanium spectrometer. Synthetic compositions with activity concentrations varying in a wide range, from 1/5 to 5 times median activity concentrations of the natural radionuclides available in the earth crust and the samples of popular building materials, such as concrete, pumice and gypsum, were tested, while the density of the tested samples changed in a wide range (from 860 up to 2,410 kg/m(3)). The results obtained in the NaI(Tl) system were similar to those obtained with the HPGe spectrometer, mostly within the uncertainty range. This comparison shows that scintillation spectrometers equipped with a special software aimed to compensate for the lower spectral resolution of NaI(Tl) detectors can be successfully used for the radiation control of mass construction products. PMID:23542118

  6. Development of scintillating fiber detector technology for high rate particle tracking

    E-print Network

    E. C. Aschenauer; J. Baehr; V. Gapienko; B. Hoffmann; A. Kharchilava; H. Luedecke; R. Nahnhauer; R. Shanidze

    1997-10-02

    The performance of a scintillating fiber detector prototype for tracking under high rate conditions is investigated. A spatial resolution of about100 micron is aimed for the detector. Further demands are low occupancy and radiation hardness up to 1 Mrad/year. Fibers with different radii and different wavelengths of the scintillation light from different producers have been extensively tested concerning light output, attenuation length and radiation hardness, with and without coupling them to light guides of different length and diameter. In a testrun at a 3 GeV electron beam the space dependent efficiency and spatial resolution of fiber bundels were measured by means of two external reference detectors with a precision of 50 micron. The light output profile across fiber roads has been determined with the same accuracy. Different technologies were adopted for the construction of tracker modules consisting of 14 layers of 0.5 mm fibers and 0.7 mm pitch. A winding technology provides reliable results to produce later fiber modules of about 25 cm x 25 cm area. We conclude that on the basis of these results a fiber tracker for high rate conditions can be built.

  7. 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.

  8. Calculations of scintillators for radiation detector systems: dependence of spectrometric characteristics on shape, size and reflector type

    Microsoft Academic Search

    M. E. Globus; B. V. Grinyov

    1995-01-01

    Spectrometric characteristics of ionizing radiation detectors based on Bi4Ge3O12 and CdWO4 scintillators were calculated as a function of size, shape (rectangular or cylindrical) and reflector type. Unlike previous work, allowance was made for the dependence of the diffuse reflection indicatrix on the light incidence angle which is of importance for light transfer in a scintillator. The calculation method was verified

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

    SciTech Connect

    Styron, J. D., E-mail: jdstyro@sandia.gov; Cooper, G. W.; Carpenter, Ken; Bonura, M. A. [Department of Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Ruiz, C. L.; Hahn, K. D.; Chandler, G. A.; Nelson, A. J.; Torres, J. A.; McWatters, B. R. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

    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.

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

    PubMed

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

    2014-11-01

    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. PMID:25430363

  11. Optimized mounting of a polyethylene naphthalate scintillation material in a radiation detector.

    PubMed

    Nakamura, Hidehito; Yamada, Tatsuya; Shirakawa, Yoshiyuki; Kitamura, Hisashi; Shidara, Zenichiro; Yokozuka, Takayuki; Nguyen, Philip; Kanayama, Masaya; Takahashi, Sentaro

    2013-10-01

    Polyethylene naphthalate (PEN) has great potential as a scintillation material for radiation detection. Here the optimum mounting conditions to maximize the light collection efficiency from PEN in a radiation detector are discussed. To this end, we have determined light yields emitted from irradiated PEN for various optical couplings between the substrate and the photodetector, and for various substrate surface treatments. The results demonstrate that light extraction from PEN is more sensitive to the optical couplings due to its high refractive index. We also assessed the extent of radioactive impurities in PEN as background sources and found that the impurities are equivalent to the environmental background level. PMID:23845742

  12. Data acquisition system for the Large Scintillating Neutrino Detector at Los Alamos

    SciTech Connect

    Anderson, G.; Cohen, I. [Linfield Coll., McMinnville, OR (United States); Homann, B.; Smith, D. [Embry-Riddle Aeronautical Univ., Daytona Beach, FL (United States); Strossman, W.; VanDalen, G.J. [California Univ., Riverside, CA (United States); Weaver, L.S.; Evans, D.; Vernon, W. [California Univ., San Diego, CA (United States); Band, A.; Burman, R.; Chang, T.; Federspiel, F.; Foreman, W.; Gomulka, S.; Hart, G.; Kozlowski, T.; Louis, W.C.; Margulies, J.; Nuanes, A.; Sandberg, V.; Thompson, T.N.; White, D.H.; Whitehouse, D. [Los Alamos National Lab., NM (United States)

    1992-10-01

    The data acquisition system for the Large Scintillating Neutrino Detector (LSND) is described. The system collects time and charge information in real time from 1600 photomultiplier tubes and passes the data in intelligent-trigger selected time windows to analysis computers, where events are reconstructed and analyzed as candidates for a variety of neutrino-related physics processes. The system is composed of fourteen VME crates linked to a Silicon Graphics, Inc. ``4D/480`` multiprocessor computer through multiple, parallel Ethernets, and a collection of contemporary high-performance workstations.

  13. Simulation study of the neutron-gamma discrimination capability of a liquid scintillator neutron detector

    NASA Astrophysics Data System (ADS)

    Xing, Haoyang; Yu, Xunzhen; Zhu, Jingjun; Wang, Li; Ma, Jinglu; Liu, Shukui; Li, Linwei; Chen, Liejian; Tang, Changjian; Yue, Qian

    2014-12-01

    The capability to discriminate between neutrons and gamma rays (n/?) by means of their pulse shapes is important for many users of liquid scintillator (LS) neutron detectors. To simulate the n/? discrimination capability of a neutron detector, we have developed a method to simulate the pulse signal generated by an incident n or ? in the LS. Light pulses caused by ionization and excitation from incident n or ? radiation are simulated by the Geant4 simulation package based on the geometry and materials of a prototype LS detector. The response to the incident light of the photomultiplier tube (PMT) and data acquisition (DAQ) circuit was obtained from a single photoelectron experiment. The final output signal from a detector was produced by convolving its light pulse with the response function of the PMT and DAQ. Two methods, the charge comparison method (CCM) and the pulse gradient method (PGM), were applied to discriminate the simulated signals. The simulation was validated by comparing its result to an experimental result from the prototype LS detector. Our method can be applied in the design of an LS detector, which has subsequently been optimized n/? discrimination. The method can also be helpful to analyze experimental data and evaluate the performance of n/? discrimination techniques.

  14. Double {beta} experiments with the help of scintillation and HPGe detectors at Gran Sasso

    SciTech Connect

    Barabash, A.; Konovalov, S. I.; Umatov, V. I. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Belli, P.; D'Angelo, S.; Di Marco, A. [INFN, Sezione di Roma ''Tor Vergata'', Rome (Italy); Bernabei, R. [INFN, Sezione di Roma ''Tor Vergata '', Rome (Italy); Dipartimento di Fisica, Universita di Roma ''Tor Vergata'', Rome (Italy); Boiko, R. S.; Chernyak, D. M.; Danevich, F. A.; Kobychev, V. V.; Kropivyansky, B. N.; Kudovbenko, V. M.; Nagorny, S. S.; Podviyanuk, R. B.; Polischuk, O. G.; Tretyak, V. I.; Vyshnevskyi, I. M.; Yurchenko, S. S. [Institute for Nuclear Research, Kyiv (Ukraine); Brudanin, V. B. [Joint Institute for Nuclear Research, Dubna (Russian Federation); and others

    2011-12-16

    A search for double beta decay of {sup 64,70}Zn, {sup 180,186}W was carried out by using low background ZnWO{sub 4} crystal scintillators, while a CeCl{sub 3} scintillation detector was applied to investigate 2{beta} processes in {sup 136,138,142}Ce. A search for 2{beta} decay of {sup 96,104}Ru, {sup 156,158}Dy, {sup 190,198}Pt and study of 2{nu}2{beta} decay of {sup 100}Mo to the first excited 0{sup +} level of {sup 100}Ru were realized by ultra-low background HPGe {gamma} spectrometry. Moreover, CdWO{sub 4} crystal scintillators from enriched {sup 106}Cd and {sup 116}Cd isotopes were developed to search for 2{beta} decay of {sup 106}Cd and {sup 116}Cd. Finally, experiments aimed to investigate {sup 96,104}Ru and {sup 116}Cd are in progress and a new phase of the experiment to search for 2{beta} processes in {sup 106}Cd is in preparation.

  15. Data-driven exploration of the ionization-phonon partitioning in scintillating radiation detector materials

    SciTech Connect

    Ferris, Kim F.; Webb-Robertson, Bobbie-Jo M.; Jordan, David V.; Jones, Dumont M.

    2008-06-01

    An information-based approach to scintillating materials development has been applied to ranking the alkali halide and alkali earth halide series in terms of their energy conversion efficiency. The efficiency of scintillating radiation detection materials can be viewed as the product of a consecutive series of electronic processes (energy conversion, transfer, and luminescence) as outlined by Lempicki and others. Relevant data are relatively sparse, but sufficient for the development of forward mapping of materials properties through materials signatures. These mappings have been used to explore the limits of the K ratio in the Lempicki model with chemical composition, and examine its relationship with another common design objective, density. The alkali halides and alkali earth halide compounds separate themselves into distinct behavior classes favoring heavier cations and anions for improved K ratio. While the coupling of ionization is strongly related to the optical phonon modes, both dielectric and band gap contributions cannot be ignored. When applied within a candidate screen, the resulting model for K imposes design rules—simple structural restrictions—on scintillating radiation detector materials.

  16. Active neutron methods for nuclear safeguards applications using Helium-4 gas scintillation detectors

    NASA Astrophysics Data System (ADS)

    Lewis, Jason M.

    Active neutron methods use a neutron source to interrogate fissionable material. In this work a 4He gas scintillation fast neutron detection system is used to measure neutrons created by the interrogation. Three new applications of this method are developed: spent nuclear fuel assay, fission rate measurement, and special nuclear material detection. Three active neutron methods are included in this thesis. First a non-destructive plutonium assay technique called Multispectral Active Neutron Interrogation Analysis is developed. It is based on interrogating fuel with neutrons at several different energies. The induced fission rates at each interrogation energy are compared with results from a neutron transport model of the irradiation geometry in a system of equations to iteratively solve the inverse problem for isotopic composition. The model is shown to converge on the correct composition for a material with 3 different fissionable components, a representative neutron absorber, and any neutron transparent material such as oxygen in a variety of geometries. Next an experimental fission rate measurement technique is developed using 4He gas scintillation fast neutron detector. Several unique features of this detector allow it to detect and provide energy information on fast neutrons with excellent gamma discrimination efficiency. The detector can measure induced fission rate by energetically differentiating between interrogation neutrons and higher energy fission neutrons. The detector response to a mono-energetic deuterium-deuterium fusion neutron generator and a 252Cf source are compared to examine the difference in detected energy range. Finally we demonstrate a special nuclear material detection technique by detecting an unambiguous fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium neutron generator and a high pressure 4He gas fast neutron scintillation detector. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. This signal path has a direct application to the determination of induced fission rate and the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection.

  17. Digital discrimination of neutrons and gamma-rays in organic scintillation detectors using moment analysis

    SciTech Connect

    Xie Xufei; Zhang Xing; Yuan Xi; Chen Jinxiang; Li Xiangqing; Zhang Guohui; Fan Tieshuan [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing (China); Yuan Guoliang; Yang Jinwei; Yang Qingwei [Southwestern Institute of Physics, Chengdu (China)

    2012-09-15

    Digital discrimination of neutron and gamma-ray events in an organic scintillator has been investigated by moment analysis. Signals induced by an americium-beryllium (Am/Be) isotropic neutron source in a stilbene crystal detector have been sampled with a flash analogue-to-digital converter (ADC) of 1 GSamples/s sampling rate and 10-bit vertical resolution. Neutrons and gamma-rays have been successfully discriminated with a threshold corresponding to gamma-ray energy about 217 keV. Moment analysis has also been verified against the results assessed by a time-of-flight (TOF) measurement. It is shown that the classification of neutrons and gamma-rays afforded by moment analysis is consistent with that achieved by digital TOF measurement. This method has been applied to analyze the data acquired from the stilbene crystal detector in mixed radiation field of the HL-2A tokamak deuterium plasma discharges and the results are described.

  18. Development of pixelated scintillation detector for highly precise time measurement in MEG upgrade

    NASA Astrophysics Data System (ADS)

    Ootani, Wataru

    2013-12-01

    The MEG experiment in search for the lepton flavor decay ?+?e+? is planned to be upgraded to reach the branching ratio sensitivity down to 5×10-14, which is one order of magnitude higher than that of the current phase of the experiment. A pixelated scintillation detector with an ultimate time resolution is under development for the positron time measurement in the upgraded experiment. Single pixel time resolutions better than 50 ps (rms) are achieved with prototype counters and an excellent overall time resolution at a level of 30-35 ps (rms) is found to be achievable in the full-scale detector by averaging the positron impact times over multiple hit counters.

  19. Digital discrimination of neutrons and gamma-rays in organic scintillation detectors using moment analysis

    NASA Astrophysics Data System (ADS)

    Xie, Xufei; Zhang, Xing; Yuan, Xi; Chen, Jinxiang; Li, Xiangqing; Zhang, Guohui; Fan, Tieshuan; Yuan, Guoliang; Yang, Jinwei; Yang, Qingwei

    2012-09-01

    Digital discrimination of neutron and gamma-ray events in an organic scintillator has been investigated by moment analysis. Signals induced by an americium-beryllium (Am/Be) isotropic neutron source in a stilbene crystal detector have been sampled with a flash analogue-to-digital converter (ADC) of 1 GSamples/s sampling rate and 10-bit vertical resolution. Neutrons and gamma-rays have been successfully discriminated with a threshold corresponding to gamma-ray energy about 217 keV. Moment analysis has also been verified against the results assessed by a time-of-flight (TOF) measurement. It is shown that the classification of neutrons and gamma-rays afforded by moment analysis is consistent with that achieved by digital TOF measurement. This method has been applied to analyze the data acquired from the stilbene crystal detector in mixed radiation field of the HL-2A tokamak deuterium plasma discharges and the results are described.

  20. A novel, SiPM-array-based, monolithic scintillator detector for PET.

    PubMed

    Schaart, Dennis R; van Dam, Herman T; Seifert, Stefan; Vinke, Ruud; Dendooven, Peter; Löhner, Herbert; Beekman, Freek J

    2009-06-01

    Silicon photomultipliers (SiPMs) are of great interest to positron emission tomography (PET), as they enable new detector geometries, for e.g., depth-of-interaction (DOI) determination, are MR compatible, and offer faster response and higher gain than other solid-state photosensors such as avalanche photodiodes. Here we present a novel detector design with DOI correction, in which a position-sensitive SiPM array is used to read out a monolithic scintillator. Initial characterization of a prototype detector consisting of a 4 x 4 SiPM array coupled to either the front or back surface of a 13.2 mm x 13.2 mm x 10 mm LYSO:Ce(3+) crystal shows that front-side readout results in significantly better performance than conventional back-side readout. Spatial resolutions <1.6 mm full-width-at-half-maximum (FWHM) were measured at the detector centre in response to an approximately 0.54 mm FWHM diameter test beam. Hardly any resolution losses were observed at angles of incidence up to 45 degrees , demonstrating excellent DOI correction. About 14% FWHM energy resolution was obtained. The timing resolution, measured in coincidence with a BaF(2) detector, equals 960 ps FWHM. PMID:19443953

  1. Production and optical properties of Gd-loaded liquid scintillator for the RENO neutrino detector

    NASA Astrophysics Data System (ADS)

    Park, J. S.; Lee, J.; Yeo, I. S.; Choi, W. Q.; Ahn, J. K.; Choi, J. H.; Choi, S.; Choi, Y.; Jang, H. I.; Jang, J. S.; Jeon, E. J.; Joo, K. K.; Kim, B. R.; Kim, H. S.; Kim, J. Y.; Kim, S. B.; Kim, S. Y.; Kim, W.; Kim, Y. D.; Lee, J. H.; Lee, J. K.; Lim, I. T.; Ma, K. J.; Pac, M. Y.; Park, I. G.; Park, K. S.; Siyeon, K.; So, S. H.; Stepanyan, S. S.; Yu, I.

    2013-04-01

    Reactor experiment for neutrino oscillation (RENO) began data-taking from August 2011. It successfully observed reactor antineutrino disappearance in April 2012 to measure the smallest mixing angle of ?13. Two identical detectors, one at near location and the other at far location, are constructed at the Yonggwang nuclear power plant in South Korea, to compare the observed reactor neutrino fluxes. Each RENO detector is filled with 16 mass tons of Gadolinium loaded liquid scintillator (GdLS) in the neutrino target region, and with 28 mass tons of unloaded liquid scintillator (LS) in the ?-catcher region surrounding the target. LS was developed to satisfy chemical, physical, optical properties, and safety requirements. Linear alkyl benzene (LAB) was chosen as a solvent because of its high flash-point, sufficient light yield, and being environmentally friendly. GdLS is carefully developed to keep a long attenuation length and high light yield for a long time period. In this paper, we report the characteristics and mass production of the RENO LS and GdLS.

  2. In-beam tests of scintillating fibre detectors at MAMI and at GSI

    E-print Network

    P. Achenbach; C. Ayerbe Gayoso; J. C. Bernauer; R. Böhm; M. O. Distler; L. Doria; M. Gómez Rodríguez de la Paz; H. Merkel; U. Müller; L. Nungesser; J. Pochodzalla; S. Sánchez Majos; B. S. Schlimme; Th. Walcher; M. Weinriefer; L. Debenjak; M. Potokar; S. Sirca; M. Kavatsyuk; O. Lepyoshkina; S. Minami; D. Nakajima; C. Rappold; T. R. Saito; D. Schardt; M. Träger; H. Iwase; S. Ajimura; A. Sakaguchi; Y. Mizoi

    2008-02-20

    The performance of scintillating fibre detectors was studied with electrons at the spectrometer facility of the Mainz microtron MAMI, as well as in a C-12 beam of 2 AGeV energy and in a beam of different particle species at GSI. Multi-anode photomultipliers were used to read out one or more bundles of 128 fibres each in different geometries. For electrons a time resolution of FWHM = 1 ns was measured in a single detector plane with a detection efficiency epsilon > 99%. A time resolution of 310 ps (FWHM) between two planes of fibres was achieved for carbon ions, leading to a FWHM = 220 ps for a single detector. The hit position residual was measured with a width of FWHM = 0.27 mm. The variation in the measured energy deposition was Delta E/E= 15-20% (FWHM) for carbon ions. In addition, the energy response to p/pi/d particles was studied. Based on the good detector performance fibre hodoscopes will be constructed for the KAOS/A1 spectrometer at MAMI and for the HypHI experiment at GSI.

  3. [Effects of ionizing radiation on scintillators and other particle detectors]. Conference summary

    SciTech Connect

    Proudfoot, J.

    1992-09-01

    It is my task to summarise the great variety of topics (covering a refreshing mix of physics, chemistry and technology) presented at this conference, which has focused on the effects of ionising radiation on scintillators and other particle detectors. One of the reasons and the central interest of many of the participants was the use of such detectors in experiments at two future large hadron colliders: the Superconducting Super Collider to be operating outside of Dallas in the United States by the turn of the decade and its European counterpart the Large Hadron Collider to be operating outside of Geneva in Switzerland on a similar time scale. These accelerators are the ``apple of the high energy physicist`s eye.`` Their goal is to uncover the elusive Higgs particle and thereby set the cornerstone in our current knowledge of elementary particle interactions. This is the Quest, and from this lofty height the presentations rapidly moved on to the specific questions of experimental science: how such an experiment is carried out; why radiation damage is an issue; how radiation damage affects detectors; which factors affect radiation damage characteristics; which factors are not affected by radiation damage; and how better detectors may be constructed. These were the substance of this conference.

  4. Simulation of optical configurations and signal processing methods in Anger-type neutron-position scintillation detector

    SciTech Connect

    Roche, C.T.; Strauss, M.G.; Brenner, R.

    1984-01-01

    The spatial linearity and resolution of Anger-type neutron-position scintillation detectors are studied using a semi-empirical model. Detector optics with either an air gap or optical grease between the scintillator and the dispersive light guide are considered. Three signal processing methods which truncate signals from PMT's distant from the scintillation are compared with the linear resistive weighting method. Air gap optics yields a 15% improvement in spatial resolution and 50% reduction in differential and integral nonlinearity relative to grease coupled optics, using linear processing. Using signal truncation instead of linear processing improves the resolution 15-20% for the air gap and 20-30% for the grease coupling case. Thus, the initial discrepancy in the resolution between the two optics nearly vanished, however the linearity of the grease coupled system is still significantly poorer.

  5. Monolithic scintillator PET detectors with intrinsic depth-of-interaction correction.

    PubMed

    Maas, Marnix C; Schaart, Dennis R; van der Laan, D J Jan; Bruyndonckx, Peter; Lemaître, Cedric; Beekman, Freek J; van Eijk, Carel W E

    2009-04-01

    We developed positron emission tomography (PET) detectors based on monolithic scintillation crystals and position-sensitive light sensors. Intrinsic depth-of-interaction (DOI) correction is achieved by deriving the entry points of annihilation photons on the front surface of the crystal from the light sensor signals. Here we characterize the next generation of these detectors, consisting of a 20 mm thick rectangular or trapezoidal LYSO:Ce crystal read out on the front and the back (double-sided readout, DSR) by Hamamatsu S8550SPL avalanche photodiode (APD) arrays optimized for DSR. The full width at half maximum (FWHM) of the detector point-spread function (PSF) obtained with a rectangular crystal at normal incidence equals approximately 1.05 mm at the detector centre, after correction for the approximately 0.9 mm diameter test beam of annihilation photons. Resolution losses of several tenths of a mm occur near the crystal edges. Furthermore, trapezoidal crystals perform almost equally well as rectangular ones, while improving system sensitivity. Due to the highly accurate DOI correction of all detectors, the spatial resolution remains essentially constant for angles of incidence of up to at least 30 degrees . Energy resolutions of approximately 11% FWHM are measured, with a fraction of events of up to 75% in the full-energy peak. The coincidence timing resolution is estimated to be 2.8 ns FWHM. The good spatial, energy and timing resolutions, together with the excellent DOI correction and high detection efficiency of our detectors, are expected to facilitate high and uniform PET system resolution. PMID:19265203

  6. Analytical calculation of the lower bound on timing resolution for PET scintillation detectors comprising high-aspect-ratio crystal elements

    NASA Astrophysics Data System (ADS)

    Cates, Joshua W.; Vinke, Ruud; Levin, Craig S.

    2015-07-01

    Excellent timing resolution is required to enhance the signal-to-noise ratio (SNR) gain available from the incorporation of time-of-flight (ToF) information in image reconstruction for positron emission tomography (PET). As the detector’s timing resolution improves, so does SNR, reconstructed image quality, and accuracy. This directly impacts the challenging detection and quantification tasks in the clinic. The recognition of these benefits has spurred efforts within the molecular imaging community to determine to what extent the timing resolution of scintillation detectors can be improved and develop near-term solutions for advancing ToF-PET. Presented in this work, is a method for calculating the Cramér–Rao lower bound (CRLB) on timing resolution for scintillation detectors with long crystal elements, where the influence of the variation in optical path length of scintillation light on achievable timing resolution is non-negligible. The presented formalism incorporates an accurate, analytical probability density function (PDF) of optical transit time within the crystal to obtain a purely mathematical expression of the CRLB with high-aspect-ratio (HAR) scintillation detectors. This approach enables the statistical limit on timing resolution performance to be analytically expressed for clinically-relevant PET scintillation detectors without requiring Monte Carlo simulation-generated photon transport time distributions. The analytically calculated optical transport PDF was compared with detailed light transport simulations, and excellent agreement was found between the two. The coincidence timing resolution (CTR) between two 3× 3× 20 mm3 LYSO:Ce crystals coupled to analogue SiPMs was experimentally measured to be 162+/- 1 ps FWHM, approaching the analytically calculated lower bound within 6.5%.

  7. Fiber optic thermal/fast neutron and gamma ray scintillation detector

    DOEpatents

    Neal, John S. (Knoxville, TN); Mihalczo, John T (Oak Ridge, TN)

    2007-10-30

    A system for detecting fissile and fissionable material originating external to the system includes: a .sup.6Li loaded glass fiber scintillator for detecting thermal neutrons, x-rays and gamma rays; a fast scintillator for detecting fast neutrons, x-rays and gamma rays, the fast scintillator conjoined with the glass fiber scintillator such that the fast scintillator moderates fast neutrons prior to their detection as thermal neutrons by the glass fiber scintillator; and a coincidence detection system for processing the time distributions of arriving signals from the scintillators.

  8. Tomographic analysis of neutron and gamma pulse shape distributions from liquid scintillation detectors at Joint European Torus.

    PubMed

    Giacomelli, L; Conroy, S; Gorini, G; Horton, L; Murari, A; Popovichev, S; Syme, D B

    2014-02-01

    The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world devoted to nuclear fusion experiments of magnetic confined Deuterium (D)/Deuterium-Tritium (DT) plasmas. Neutrons produced in these plasmas are measured using various types of neutron detectors and spectrometers. Two of these instruments on JET make use of organic liquid scintillator detectors. The neutron emission profile monitor implements 19 liquid scintillation counters to detect the 2.45 MeV neutron emission from D plasmas. A new compact neutron spectrometer is operational at JET since 2010 to measure the neutron energy spectra from both D and DT plasmas. Liquid scintillation detectors are sensitive to both neutron and gamma radiation but give light responses of different decay time such that pulse shape discrimination techniques can be applied to identify the neutron contribution of interest from the data. The most common technique consists of integrating the radiation pulse shapes within different ranges of their rising and/or trailing edges. In this article, a step forward in this type of analysis is presented. The method applies a tomographic analysis of the 3-dimensional neutron and gamma pulse shape and pulse height distribution data obtained from liquid scintillation detectors such that n/? discrimination can be improved to lower energies and additional information can be gained on neutron contributions to the gamma events and vice versa. PMID:24593359

  9. Tomographic analysis of neutron and gamma pulse shape distributions from liquid scintillation detectors at Joint European Torus

    SciTech Connect

    Giacomelli, L. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom) [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Department of Physics, Università degli Studi di Milano-Bicocca, Milano (Italy); Conroy, S. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom) [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Department of Physics and Astronomy, Uppsala University, Uppsala (Sweden); Gorini, G. [Department of Physics, Università degli Studi di Milano-Bicocca, Milano (Italy)] [Department of Physics, Università degli Studi di Milano-Bicocca, Milano (Italy); Horton, L.; Murari, A.; Popovichev, S.; Syme, D. B. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)] [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)

    2014-02-15

    The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world devoted to nuclear fusion experiments of magnetic confined Deuterium (D)/Deuterium-Tritium (DT) plasmas. Neutrons produced in these plasmas are measured using various types of neutron detectors and spectrometers. Two of these instruments on JET make use of organic liquid scintillator detectors. The neutron emission profile monitor implements 19 liquid scintillation counters to detect the 2.45 MeV neutron emission from D plasmas. A new compact neutron spectrometer is operational at JET since 2010 to measure the neutron energy spectra from both D and DT plasmas. Liquid scintillation detectors are sensitive to both neutron and gamma radiation but give light responses of different decay time such that pulse shape discrimination techniques can be applied to identify the neutron contribution of interest from the data. The most common technique consists of integrating the radiation pulse shapes within different ranges of their rising and/or trailing edges. In this article, a step forward in this type of analysis is presented. The method applies a tomographic analysis of the 3-dimensional neutron and gamma pulse shape and pulse height distribution data obtained from liquid scintillation detectors such that n/? discrimination can be improved to lower energies and additional information can be gained on neutron contributions to the gamma events and vice versa.

  10. Nuclear Instruments and Methods in Physics Research A 565 (2006) 650656 Semiconductor high-energy radiation scintillation detector

    E-print Network

    Luryi, Serge

    2006-01-01

    semiconductor material (such as InP or GaAs), the photo-detector and associated circuits can be epitaxially: Semiconductor scintillator; Direct-gap semiconductors; InP; GaAs; Burstein shift; 3D integration 1. IntroductionNuclear Instruments and Methods in Physics Research A 565 (2006) 650­656 Semiconductor high

  11. A count-rate model for PET scanners using pixelated Anger-logic detectors with different scintillators

    Microsoft Academic Search

    S. Surti; J. S. Karp

    2005-01-01

    A high count-rate simulation (HCRSim) model has been developed so that all results are derived from fundamental physics principles. Originally developed to study the behaviour of continuous sodium iodide (NaI(Tl)) detectors, this model is now applied to PET scanners based on pixelated Anger-logic detectors using lanthanum bromide (LaBr3), gadolinium orthosilicate (GSO) and lutetium orthosilicate (LSO) scintillators. This simulation has been

  12. Energy resolution of scintillation detectors readout with large area avalanche photodiodes and photomultipliers

    SciTech Connect

    Moszynski, M.; Wolski, D. [Soltan Inst. for Nuclear Studies, Swierk-Otwock (Poland)] [Soltan Inst. for Nuclear Studies, Swierk-Otwock (Poland); Kapusta, M. [Soltan Inst. for Nuclear Studies, Swierk-Otwock (Poland)] [Soltan Inst. for Nuclear Studies, Swierk-Otwock (Poland); [Univ. of Warsaw (Poland). Inst. of Experimental Physics; Szawlowski, M. [Advanced Photonix, Inc., Camarillo, CA (United States)] [Advanced Photonix, Inc., Camarillo, CA (United States); Klamra, W. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Physics] [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Physics

    1998-06-01

    The energy resolution of small NaI(Tl), CsI(Tl), BGO, GSO, YAP and LSO crystals has been studied using 16 mm diameter large area avalanche photodiodes (LAAPD) and a 52 mm diameter photomultiplier. The best result of 4.8% for 662 keV {gamma}-rays from a {sup 137}Cs source was obtained with a 9 mm in diameter by 9 mm high CsI(Tl) scintillator coupled to an LAAPD. Measuring the number of primary electron-hole pairs produced in the LAAPD and photoelectrons in the photomultiplier, as well as the noise contribution of the LAAPD, allowed a quantitative discussion of the results. The energy resolutions measured with LAAPDs are comparable to, or significantly better (at certain emission wavelengths) than, those obtained with the photomultiplier. At energies above 100 keV the energy resolution measured with the majority of crystals and the LAAPD was weakly affected by the photodiode noise contribution. The advantages and limitations of LAAPDs in energy spectrometry with scintillation detectors are also discussed.

  13. A LSO scintillator array for a PET detector module with depth of interaction measurement

    SciTech Connect

    Huber, J.S.; Moses, W.W.; Andreaco, M.S.; Petterson, O.

    2000-10-30

    We present construction methods and performance results for a production scintillator array of 64 optically isolated, 3 mm x 3 mm x 30 mm sized LSO crystals. This scintillator array has been developed for a PET detector module consisting of the 8x8 LSO array coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PD). The PMT provides an accurate timing pulse and initial energy discrimination, the PD identifies the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction (DOI). Unlike the previous LSO array prototypes, we now glue Lumirror reflector material directly onto 4 sides of each crystal to obtain an easily manufactured, mechanically rugged array with our desired depth dependence. With 511 keV excitation, we obtain a total energy signal of 3600 electrons, pulse-height resolution of 25% fwhm, and 6-15 mm fwhm DOI resolution.

  14. 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.

  15. Toward a Real-Time In Vivo Dosimetry System Using Plastic Scintillation Detectors

    SciTech Connect

    Archambault, Louis; Briere, Tina M.; Poenisch, Falk [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Beaulieu, Luc [Departement de Radio-oncologie, Centre Hospitalier Universitaire de Quebec, Quebec, QC (Canada); Kuban, Deborah A.; Lee, Andrew [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Beddar, Sam, E-mail: beddar@mdanderson.or [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2010-09-01

    Purpose: In the present study, we have presented and validated a plastic scintillation detector (PSD) system designed for real-time multiprobe in vivo measurements. Methods and Materials: The PSDs were built with a dose-sensitive volume of 0.4 mm{sup 3}. The PSDs were assembled into modular detector patches, each containing five closely packed PSDs. Continuous dose readings were performed every 150 ms, with a gap between consecutive readings of <0.3 ms. We first studied the effect of electron multiplication. We then assessed system performance in acrylic and anthropomorphic pelvic phantoms. Results: The PSDs were compatible with clinical rectal balloons and were easily inserted into the anthropomorphic phantom. With an electron multiplication average gain factor of 40, a twofold increase in the signal/noise ratio was observed, making near real-time dosimetry feasible. Under calibration conditions, the PSDs agreed with the ion chamber measurements to 0.08%. Precision, evaluated as a function of the total dose delivered, ranged from 2.3% at 2 cGy to 0.4% at 200 cGy. Conclusion: Real-time PSD measurements are highly accurate and precise. These PSDs can be mounted onto rectal balloons, transforming these clinical devices into in vivo dose detectors without modifying current clinical practice. Real-time monitoring of the dose delivered near the rectum during prostate radiotherapy should help radiation oncologists protect this sensitive normal structure.

  16. A practical method for depth of interaction determination in monolithic scintillator PET detectors.

    PubMed

    van Dam, Herman T; Seifert, Stefan; Vinke, Ruud; Dendooven, Peter; Löhner, Herbert; Beekman, Freek J; Schaart, Dennis R

    2011-07-01

    Several new methods for determining the depth of interaction (DOI) of annihilation photons in monolithic scintillator detectors with single-sided, multi-pixel readout are investigated. The aim is to develop a DOI decoding method that allows for practical implementation in a positron emission tomography system. Specifically, calibration data, obtained with perpendicularly incident gamma photons only, are being used. Furthermore, neither detector modifications nor a priori knowledge of the light transport and/or signal variances is required. For this purpose, a clustering approach is utilized in combination with different parameters correlated with the DOI, such as the degree of similarity to a set of reference light distributions, the measured intensity on the sensor pixel(s) closest to the interaction position and the peak intensity of the measured light distribution. The proposed methods were tested experimentally on a detector comprised of a 20 mm × 20 mm × 12 mm polished LYSO:Ce crystal coupled to a 4 × 4 multi-anode photomultiplier. The method based on the linearly interpolated measured intensities on the sensor pixels closest to the estimated (x, y)-coordinate outperformed the other methods, yielding DOI resolutions between ?1 and ?4.5 mm FWHM depending on the DOI, the (x, y) resolution and the amount of reference data used. PMID:21693789

  17. Monte Carlo study of the time resolution of scintillating fibre detectors

    NASA Astrophysics Data System (ADS)

    Ziembicki, M.; Marzec, J.; Dziewiecki, M.

    2007-08-01

    This paper presents the results of a Monte Carlo study of the time resolution of a scintillating fibre detector and analyses its dependence on the various aspects of detector construction. The estimations of the theoretical time resolutions for detectors with different numbers of fibre layers and different types of acrylic-based fibre coatings are presented. The method is suggested to decrease the rate counting effects encountered in high rate applications. It has been observed that for dual cladding fibres with a fluorinated polymer used for the outer cladding, the most significant factor contributing to the time resolution is the number of fibre layers, with the fibre coating being the marginal one. Another observation shows that the introduction of a gap between the fibre and the photomultiplier glass window allows the reduction of the number of photoelectrons by 25% with only a slight decrease in the time resolution, which may be helpful in decreasing the pulse pile-up effects and the photomultiplier gain, commonly observed under high rate conditions.

  18. ecCNO solar neutrinos: A challenge for gigantic ultra-pure liquid scintillator detectors

    NASA Astrophysics Data System (ADS)

    Villante, F. L.

    2015-03-01

    Neutrinos produced in the Sun by electron capture reactions on 13N, 15O and 17F, to which we refer as ecCNO neutrinos, are not usually considered in solar neutrino analysis since the expected fluxes are extremely low. The experimental determination of this sub-dominant component of the solar neutrino flux is very difficult but could be rewarding since it provides a determination of the metallic content of the solar core and, moreover, probes the solar neutrino survival probability in the transition region at E? ? 2.5 MeV. In this Letter, we suggest that this difficult measure could be at reach for future gigantic ultra-pure liquid scintillator detectors, such as LENA.

  19. Analytical calculation of the lower bound on timing resolution for PET scintillation detectors comprising high-aspect-ratio crystal elements.

    PubMed

    Cates, Joshua W; Vinke, Ruud; Levin, Craig S

    2015-07-01

    Excellent timing resolution is required to enhance the signal-to-noise ratio (SNR) gain available from the incorporation of time-of-flight (ToF) information in image reconstruction for positron emission tomography (PET). As the detector's timing resolution improves, so does SNR, reconstructed image quality, and accuracy. This directly impacts the challenging detection and quantification tasks in the clinic. The recognition of these benefits has spurred efforts within the molecular imaging community to determine to what extent the timing resolution of scintillation detectors can be improved and develop near-term solutions for advancing ToF-PET. Presented in this work, is a method for calculating the Cramér-Rao lower bound (CRLB) on timing resolution for scintillation detectors with long crystal elements, where the influence of the variation in optical path length of scintillation light on achievable timing resolution is non-negligible. The presented formalism incorporates an accurate, analytical probability density function (PDF) of optical transit time within the crystal to obtain a purely mathematical expression of the CRLB with high-aspect-ratio (HAR) scintillation detectors. This approach enables the statistical limit on timing resolution performance to be analytically expressed for clinically-relevant PET scintillation detectors without requiring Monte Carlo simulation-generated photon transport time distributions. The analytically calculated optical transport PDF was compared with detailed light transport simulations, and excellent agreement was found between the two. The coincidence timing resolution (CTR) between two [Formula: see text] mm[Formula: see text] LYSO:Ce crystals coupled to analogue SiPMs was experimentally measured to be [Formula: see text] ps FWHM, approaching the analytically calculated lower bound within 6.5%. PMID:26083559

  20. Limiting factors for the scintillation detector coincidence resolving time in positron emission tomography

    PubMed Central

    Derenzo, Stephen E.; Choong, Woon-Seng; Moses, William W.

    2015-01-01

    We present Monte Carlo computational methods for estimating the coincidence resolving time (CRT) of scintillator detector pairs in positron emission tomography (PET) and present results for Lu2SiO5:Ce (LSO), LaBr3:Ce, and a hypothetical ultra-fast scintillator with a 1 ns decay time. The calculations were applied to both single-ended and double-ended photodetector readout with leading-edge triggering. They explicitly include (1) the intrinsic scintillator properties (luminosity, rise time, decay time, and index of refraction), (2) the exponentially distributed depths of interaction, (3) the optical photon transport efficiency, delay, and time dispersion, (4) the photodetector properties (fill factor, quantum efficiency, transit time jitter, and single electron response), and (5) the determination of the trigger level that optimizes the CRT. The calculations for single-ended readout include the delayed photons from the opposite reflective surface. The calculations for double-ended readout include the simple average of the two photodetector trigger times, as well as more accurate estimators of the annihilation photon entrance time using the pulse height ratio to estimate the depth of interaction and correct for annihilation photon, optical photon, and trigger delays. For time-of-flight (TOF) PET we combine stopping power and TOF information in a figure of merit equal to the sensitivity gain relative to whole-body non-TOF PET using LSO. For LSO, a decay time of 37 ns, a total photoelectron count of 4,000, and a photodetector with 0.2 ns full-width at half-maximum (fwhm) timing jitter, single-ended readout has a CRT of 0.16 ns fwhm and double-ended readout has a CRT of 0.111 ns fwhm. For LaBr3:Ce, a rise time of 0.2 ns, a decay time of 18 ns, and a total of 7,600 photoelectrons the CRT numbers are 0.14 and 0.072 ns fwhm, respectively. For a the ultra-fast scintillator with a decay time of 1 ns and a total of 4,000 photoelectrons, the CRT numbers are 0.070 and 0.020 ns fwhm, respectively. PMID:24922188

  1. Development of a novel scintillation-trigger detector for the MTV experiment using aluminum-metallized film tapes

    E-print Network

    S. Tanaka; S. Ozaki; Y. Sakamoto; R. Tanuma; T. Yoshida; J. Murata

    2014-03-13

    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 $\\pm$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.

  2. A gated liquid-scintillator-based neutron detector for fast-ignitor experiments and down-scattered neutron measurements.

    PubMed

    Stoeckl, C; Cruz, M; Glebov, V Yu; Knauer, J P; Lauck, R; Marshall, K; Mileham, C; Sangster, T C; Theobald, W

    2010-10-01

    The detection of neutrons in fast-ignitor experiments or down-scattered neutrons in inertial fusion experiments is very challenging since it requires the neutron detection system to recover within 10-100 ns from a high background orders of magnitude stronger than the signal of interest. The background is either the hard x-ray emission from short-pulse laser target interactions for the fast-ignitor experiments or the primary neutron signal for the down-scattered neutrons. A liquid-scintillator detector has been developed using a gated photomultiplier that suppresses the background signal and eliminates the afterglow present in conventional plastic scintillators. PMID:21033828

  3. 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.

  4. 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

  5. A Unique TAS Setup for high multiplicity events at VECC, Kolkata using BaF2 detectors

    NASA Astrophysics Data System (ADS)

    Mukherjee, G.; Dey, Balaram; Mukhopadhyay, S.; Pandit, Deepak; Pal, Surajit; Pai, H.; Banerjee, S. R.

    2014-03-01

    A granular total absorption spectrometer (TAS) has been developed at the Variable Energy Cyclotron Centre, Kolkata, India using 50 elements of BaF2 detectors and covering 4?. The advantage with such a granular setup is that one can get sum spectrum with the condition of different multiplicity hits in an event. It has been shown that one can get clean sum-peaks devoid of individual peaks with the choice of two or higher fold of multiplicity. The large granularity makes it a unique TAS setup particularly for the high multiplicity events. The set up has been tested using different radioactive sources with one, two or multiple ? rays in cascade. The set up is ready to be used online.

  6. A position sensitive gamma-ray scintillator detector with enhanced spatial resolution, linearity, and field of view.

    PubMed

    Domingo-Pardo, César; Goel, Namita; Engert, Tobias; Gerl, Juergen; Isaka, Masahiro; Kojouharov, Ivan; Schaffner, Henning

    2009-12-01

    The performance of a position sensitive gamma-ray scintillator detector (PSD) is described. This PSD is based on a lutetium yttrium oxyorthosilicate (LYSO) crystal read out by a crossed-wire anode position sensitive photomultiplier tube (PSPMT). The main difference with respect to similar existing devices is the individual multi-anode readout (IMAR) approach that is followed here. This method allows to exploit better the intrinsic characteristics of the PSPMT, thus yielding better linearity, improved spatial resolution, and a larger field of view. The new detector is intended for the characterization of 3-D position sensitive germanium detectors. PMID:19628451

  7. Comparative investigation of the performance of ZnO-based scintillators for use as ?-particle detectors

    Microsoft Academic Search

    John S Neal; Lynn A Boatner; N. C. Giles; L. E. Halliburton; S. E. Derenzo; E. D. Bourret-Courchesne

    2006-01-01

    As part of a comprehensive investigation of the scintillation properties of zinc-oxide-based scintillators, four samples of gallium-doped zinc oxide (ZnO) powders have been characterized by means of X-ray excitation, ?-particle excitation, and temperature-dependent photoluminescence (PL). The ultimate goals of these studies are, first, to understand the scintillation mechanisms that are operative in various members of the ZnO family of scintillators,

  8. Conceptual design for a scintillating-fiber neutron detector for fusion reactor plasma diagnostics

    SciTech Connect

    Sailor, W.C.; Barnes, C.W.; Chrien, R.E.; Wurden, G.A.

    1994-07-01

    A conceptual design for a ``pointing`` neutron detector that is capable of delivering 10{sup 4} - 10{sup 5} Hz countrate of T(D,n) events from triton burnup at a deuterium-burning tokamak is described. The detector consists of collimated bundles of scintillating fibers that are separated by metal or polyethylene. These bundles in turn are set into a larger collimator that has some of the bundles set in ``unplugged`` holes and others in ``plugged`` holes whose countrate difference gives the net countrate. It is computed that the use of a 6 MeV{sub ee} (electron equivalent) discriminator will allow 14-MeV neutron countrates of 2xl0{sup 4} Hz in a DD machine or 3 MHz in a DT machine, while effectively rejecting the gamma background. The efficiency-area product for 14-MeV neutrons will be {similar_to} 0.014 cm{sup 2}. The angular resolution is computed to be 4.5{degree} HWHM for a 35 cm long collimator.

  9. Radiation damage in scintillator detector chemical compounds: a new approach using PPO-Toluene liquid scintillator as a model

    Microsoft Academic Search

    C. H. Mesquita; J. M. Fernandes Neto; C. L. Duarte; P. R. Rela; M. M. Hamada

    2002-01-01

    The effect of radiation damage was evaluated in PPO-Toluene liquid scintillator solution. Samples containing PPO (1% w\\/v) diluted in toluene were prepared and irradiated at different doses, using a 60Co irradiator at 1.8 Gy\\/s. The effect of radiation on transmittance, light output, and chemical modification in the PPO were evaluated before and after irradiation. Transmittance loss at 360 nm decayed

  10. A compact and high sensitivity positron detector using dual-layer thin GSO scintillators for a small animal PET blood sampling system

    Microsoft Academic Search

    Seiichi Yamamoto; Masao Imaizumi; Eku Shimosegawa; Yasukazu Kanai; Yusuke Sakamoto; Kotaro Minato; Keiji Shimizu; Michio Senda; Jun Hatazawa

    2010-01-01

    For quantitative measurements of small animals such as mice or rats, a compact and high sensitivity continuous blood sampling detector is required because their blood sampling volume is limited. For this purpose we have developed and tested a new positron detector. The positron detector uses a pair of dual-layer thin gadolinium orthosilicate (GSO) scintillators with different decay times. The front

  11. 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 [Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada)

    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, respectively. Furthermore, volume averaging of the IC can be observed for the 5 mm aperture where it differs by as much as 9.1% compared to the PSD measurement. The angular dependency of the UD is also observed, unveiled by an under-response around 2.5% of both 5 and 35 mm apertures. Conclusions: Output Factors and dose profiles measurements performed, respectively, with the PSD and the PSDCA were in agreement with those obtained with the UD and EBT2 films. For stereotactic radiosurgery treatment verification, the PSD gives accurate results compared to the planning system and the IC once the latter is corrected to compensate for the averaging effect of the IC. The PSD provides precise results when used as a single detector or in a dense array, resulting in a great potential for stereotactic radiosurgery QA measurements.

  12. A Monte Carlo study of an energy-weighted algorithm for radionuclide analysis with a plastic scintillation detector.

    PubMed

    Shin, Wook-Geun; Lee, Hyun-Cheol; Choi, Chang-Il; Park, Chang Soo; Kim, Hong-Suk; Min, Chul Hee

    2015-07-01

    Nuisance and false alarms due to naturally occurring radioactive material (NORM) are major problems facing radiation portal monitors (RPMs) for the screening of illicit radioactive materials in airports and ports. Based on energy-weighted counts, we suggest an algorithm that distinguishes radioactive nuclides with a plastic scintillation detector that has poor energy resolution. Our simulation study, using a Monte Carlo method, demonstrated that man-made radionuclides can be separated from NORM by using a conventional RPM. PMID:25836977

  13. Calculations of scintillators for radiation detector systems: dependence of spectrometric characteristics on shape, size and reflector type

    Microsoft Academic Search

    M. E. Globus; B. V. Grinyov

    1994-01-01

    Spectrometric characteristics of ionizing radiation detectors based on Bi4Ge3O12 and CdWO4 scintillators were calculated depending on sizes, shape (rectangular or cylindrical) and reflector type. Unlike other known publications, allowance was made for the dependence of the diffuse reflection indicatrix on the light incidence angle which is of importance for forming the light flows. The calculated method is verified by the

  14. Beta Spectrometers with Surface Barrier Detector and Plastic Scintillator: Applications to 90 Sr,204Tl,210Pb and 14C

    Microsoft Academic Search

    Cuneyt C EL

    In this work, a comparison of responses between a spectrometer using Si Surface Barrier Detector (Si SBD) and a spectrometer using Plastic Scintillator (PS) is given. Experimental pulse height spectra of beta particles from 90Sr,204Tl,210Pb and 14C pure beta sources has been obtained separately. By comparing obtained spectra, the priority of obtaining the beta spectra among them is discussed. This

  15. Beta Spectrometers with Surface Barrier Detector and Plastic Scintillator: Applications to 90Sr,204Tl,210Pb and 14C

    Microsoft Academic Search

    Cüneyt Çelýktaþ

    2001-01-01

    In this work, a comparison of responses between a spectrometer using Si Surface Barrier Detector (Si SBD) and a spectrometer using Plastic Scintillator (PS) is given. Experimental pulse height spectra of beta particles from 90Sr,204Tl,210Pb and 14C pure beta sources has been obtained separately. By comparing obtained spectra, the priority of obtaining the beta spectra among them is discussed. This

  16. Homestake tracking spectrometer: a one-mile deep 1400-ton liquid-scintillation nucleon-decay detector

    Microsoft Academic Search

    M. L. Cherry; I. Davidson; K. Lande; C. K. Lee; E. Marshall; R. I. Steinberg; B. Cleveland; R. Jr. Davis; D. Lowenstein

    1982-01-01

    We describe a proposed nucleon decay detector able to demonstrate the existence of nucleon decay for lifetimes up to 5 x 10³² yr. The proposed instrument is a self-vetoed completely-active 1400-ton liquid scintillation Tracking Spectrometer to be located in the Homestake Mine at a depth of 4200 mwe, where the cosmic ray muon flux is only 1100\\/m²\\/yr, more than 10⁷

  17. Determination of neutrino incoming direction in the CHOOZ experiment and its application to supernova explosion location by scintillator detectors

    Microsoft Academic Search

    M. Apollonio; A. Baldini; C. Bemporad; E. Caffau; F. Cei; Y. Déclais; H. de Kerret; B. Dieterle; A. Etenko; L. Foresti; J. George; G. Giannini; M. Grassi; Y. Kozlov; W. Kropp; D. Kryn; M. Laiman; B. Lefièvre; I. Machulin; A. Martemyanov; V. Martemyanov; L. Mikaelyan; D. Nicolò; M. Obolensky; R. Pazzi; G. Pieri; L. Price; S. Riley; R. Reeder; A. Sabelnikov; G. Santin; M. Skorokhvatov; H. Sobel; J. Steele; R. Steinberg; S. Sukhotin; S. Tomshaw; D. Veron; V. Vyrodov

    2000-01-01

    The CHOOZ experiment has measured the antineutrino flux at about 1 km from two nuclear reactors to search for possible nu¯e-->nu¯x oscillations with mass-squared differences as low as 10-3 eV2 for full mixing. We show that the analysis of the ~2700 nu¯e events, collected by our liquid scintillation detector, locates the antineutrino source within a cone of half-aperture ~18° at

  18. A digital approach to neutron-? imaging with a narrow tungsten collimator aperture and a fast organic liquid scintillator detector.

    PubMed

    Gamage, K A A; Joyce, M J; Taylor, G C

    2012-07-01

    A digital neutron-? imaging technique for mixed radiation field is described. The imaging system is based upon an organic liquid scintillator detector, a narrow tungsten collimator, fast digitiser and adjustable equatorial mount. Radioactive sources have been attached to a vertical plane and the digitiser has been used to digitise neutron and ? events. The digitised events have been discriminated using pulse gradient analysis and images have been generated of the count distribution in the source plane. PMID:22321491

  19. DETECTORS AND EXPERIMENTAL METHODS: Study of the characteristics of a scintillation array and single pixels for nuclear medicine imaging applications

    Microsoft Academic Search

    Jie Zhu; Hong-Guang Ma; Wen-Yan Ma; Hui Zeng; Zhao-Min Wang; Zi-Zong Xu

    2009-01-01

    By using a pixelized Nal(Tl) crystal array coupled to a R2486 PSPMT, the characteristics of the array and of a single pixel, such as the light output, energy resolution, peak-to-valley ratio (P\\/V) and imaging performance of the detector were studied. The pixel size of the NaI(TI) scintillation pixel array is 2 mm×2 mm×5 mm. There are in total 484 pixels

  20. Gamma-ray spectroscopy with LaBr3:Ce scintillator readout by a silicon drift detector

    Microsoft Academic Search

    C. Fiorini; A. Gola; M. Zanchi; A. Longoni; P. Lechner; H. Soltau; L. Struder

    2005-01-01

    In this work we propose a gamma-ray spectrometer based on a LaBr3:Ce scintillator coupled to a silicon drift detector (SDD). The SDD is a photodetector characterized by a very low noise thanks to the low value of output capacitance independent from the active area. With respect to a PMT, the SDD offers a higher quantum efficiency which reduces the spread

  1. Low noise scintillation detectors with a P-47 thin layer screen for electrons of several keV

    NASA Astrophysics Data System (ADS)

    Kajcsos, Zs.; Meisel, W.; Griesbach, P.; Gütlich, P.; Sauer, Ch.; Kurz, R.; Hildebrand, K.; Albrecht, R.; Ligtenberg, M. A. C.

    1994-09-01

    The applicability of a low-noise scintillation detector (ScD) for the registration of electrons of several keV energy has been studied employing photomultipliers (PM) of different types and sizes. With the application of a sedimented P-47 scintillation screen, the values of the low-energy sensitivity limit and those of the light conversion coefficient were determined as about 2.7-4.7 keV and 2.8-6.6 photoelectrons/keV, respectively, for the set of PM's (Philips-Valvo XP 2020, Philips-Valvo XP 2052, Philips-Valvo XP 2972, EMI 9124a) studied. It is concluded that such scintillation detectors might be used advantageously as electron counters in the range of E > 5 keV. Applications below this kinetic energy value are also feasible when applying a floating acceleration of several kV to the ScD — a voltage much lower than the values required for Everhart-Thornley detectors.

  2. Novel discrimination parameters for neutron-gamma discrimination with liquid scintillation detectors using wavelet transform

    NASA Astrophysics Data System (ADS)

    Singh, H.; Singh, S.

    2015-06-01

    It has been observed that the discrimination performance of the wavelet transform method strongly depends on definition of discrimination parameters. These parameters are usually obtained from a combination of scaling functions at different scales, which represents the energy density of the wavelet coefficients. In this paper, the discrete wavelet transform (DWT) at minimum possible values of scale was investigated. Novel pulse shape discrimination parameters have been proposed for neutron and gamma discrimination in a mixed radiation field and tested with modeled pulses. The performance of these parameters was also validated in terms of quality of discrimination using experimental data of mixed events from an AmBe source collected with BC501 liquid scintillation detector. The quality of discrimination was evaluated by calculating a figure of merit (FOM) with all parameters under same experimental and simulation conditions. The FOM obtained with the proposed novel parameters was also compared with the charge comparison method. The proposed parameters exhibit better FOM as compared to the charge comparison method when high levels of noise are present in the data.

  3. Extraction of depth-dependent perturbation factors for silicon diodes using a plastic scintillation detector

    SciTech Connect

    Lacroix, Frederic; Guillot, Mathieu; McEwen, Malcolm; Gingras, Luc; Beaulieu, Luc [Departement de Radio-Oncologie, Centre hospitalier de l'Universite de Montreal (CHUM), 1560 Sherbrooke est, Montreal, Quebec H2L 4M1, Canada and Departement de Physique, Universite de Montreal, Pavillon Roger-Gaudry (D-428), 2900 Boul. Edouard-Montpetit, Montreal, Quebec H3T 1J4 (Canada); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec G1K 7P4, Quebec, Canada and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre hospitalier universitaire de Quebec (CHUQ), Quebec, Quebec G1R 2J6 (Canada); Ionizing Radiation Standards, Institute for National Measurement Standards, National Research Council (NRC), Ottawa, Ontario K1A 0R6 (Canada); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec G1K 7P4, Quebec, Canada and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre hospitalier universitaire de Quebec (CHUQ), Quebec, Quebec G1R 2J6 (Canada)

    2011-10-15

    Purpose: This work presents the experimental extraction of the perturbation factor in megavoltage electron beams for three models of silicon diodes (IBA Dosimetry, EFD and SFD, and the PTW 60012 unshielded) 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. They also measured depth-dose curves using the IBA Dosimetry, EFD and SFD, and the PTW 60012 unshielded diodes. The authors used the depth-dose curves measured with the PSD as a perturbation-free reference to extract the perturbation factors of the diodes. Results: The authors found that the perturbation factors for the diodes increased substantially with depth, especially for low-energy electron beams. The experimental results show the same trend as published Monte Carlo simulation results for the EFD diode; however, the perturbations measured experimentally were greater. They found that using an effective point of measurement (EPOM) placed slightly away from the source reduced the variation of perturbation factors with depth and that the optimal EPOM appears to be energy dependent. Conclusions: The manufacturer recommended EPOM appears to be incorrect at low electron energy (6 MeV). In addition, the perturbation factors for diodes may be greater than predicted by Monte Carlo simulations.

  4. Properties of LYSO and recent LSO scintillators for phoswich PET detectors

    Microsoft Academic Search

    Catherine Michelle Pepin; Philippe Bérard; Anne-Laure Perrot; Claude Pépin; Daniel Houde; Roger Lecomte; Charles L. Melcher; Henri Dautet

    2004-01-01

    The luminescence and nuclear spectroscopic properties of the new cerium-doped rare-earth scintillator lutetium-yttrium oxyorthosilicate (Lu0.6Y1.4Si0.5:Ce, LYSO) were investigated and compared to those of both recent and older LSO crystals. UV-excited luminescent spectra outline important similarities between LYSO and LSO scintillators. The two distinct Ce1 and Ce2 luminescence mechanisms previously identified in LSO are also present in LYSO scintillators. The energy

  5. Progress of performance of MOEMS micro spectrometers through enhanced signal processing, detectors and system setup

    NASA Astrophysics Data System (ADS)

    Grüger, Heinrich; Egloff, Thomas; Messerschmidt, Matthias; Scholles, Michael

    2008-09-01

    Micro spectrometers have been realized by the use of MEMS based scanning grating chips several years ago. The main advantage is the requirement of a single detector instead of a detector array for micro spectrometers applying fixed gratings. Especially in the near infrared range beyond the detection limit of silicon detectors, this can help to reduce the system costs significantly. First measurements for test application have been performed successfully. Industrial applications require wide spectral range, high long term stability and sufficient computation power in the system itself to realize intelligent sensor heads for process monitoring and quality control. Through the recent time, many details have been improved. Extended InGaAs detectors have been used to extend the spectral range up to 2500nm. Improvements of the grating position readout improved the wavelength stability of the system even under tough operation conditions. The integration of faster digital signal processors opens the possibility to implement spectral evaluation algorithms into the system itself. Besides simple applications shown earlier like the selection of different kinds of plastic waste, now a more quantitative analysis can be achieved. For example the ethanol content of liquor samples has been measured and evaluated quantitatively.

  6. Sub-200 ps CRT in monolithic scintillator PET detectors using digital SiPM arrays and maximum likelihood interaction time estimation

    NASA Astrophysics Data System (ADS)

    van Dam, Herman T.; Borghi, Giacomo; Seifert, Stefan; Schaart, Dennis R.

    2013-05-01

    Digital silicon photomultiplier (dSiPM) arrays have favorable characteristics for application in monolithic scintillator detectors for time-of-flight positron emission tomography (PET). To fully exploit these benefits, a maximum likelihood interaction time estimation (MLITE) method was developed to derive the time of interaction from the multiple time stamps obtained per scintillation event. MLITE was compared to several deterministic methods. Timing measurements were performed with monolithic scintillator detectors based on novel dSiPM arrays and LSO:Ce,0.2%Ca crystals of 16 × 16 × 10 mm3, 16 × 16 × 20 mm3, 24 × 24 × 10 mm3, and 24 × 24 × 20 mm3. The best coincidence resolving times (CRTs) for pairs of identical detectors were obtained with MLITE and measured 157 ps, 185 ps, 161 ps, and 184 ps full-width-at-half-maximum (FWHM), respectively. For comparison, a small reference detector, consisting of a 3 × 3 × 5 mm3 LSO:Ce,0.2%Ca crystal coupled to a single pixel of a dSiPM array, was measured to have a CRT as low as 120 ps FWHM. The results of this work indicate that the influence of the optical transport of the scintillation photons on the timing performance of monolithic scintillator detectors can at least partially be corrected for by utilizing the information contained in the spatio-temporal distribution of the collection of time stamps registered per scintillation event.

  7. Sub-200 ps CRT in monolithic scintillator PET detectors using digital SiPM arrays and maximum likelihood interaction time estimation.

    PubMed

    van Dam, Herman T; Borghi, Giacomo; Seifert, Stefan; Schaart, Dennis R

    2013-05-21

    Digital silicon photomultiplier (dSiPM) arrays have favorable characteristics for application in monolithic scintillator detectors for time-of-flight positron emission tomography (PET). To fully exploit these benefits, a maximum likelihood interaction time estimation (MLITE) method was developed to derive the time of interaction from the multiple time stamps obtained per scintillation event. MLITE was compared to several deterministic methods. Timing measurements were performed with monolithic scintillator detectors based on novel dSiPM arrays and LSO:Ce,0.2%Ca crystals of 16 × 16 × 10 mm(3), 16 × 16 × 20 mm(3), 24 × 24 × 10 mm(3), and 24 × 24 × 20 mm(3). The best coincidence resolving times (CRTs) for pairs of identical detectors were obtained with MLITE and measured 157 ps, 185 ps, 161 ps, and 184 ps full-width-at-half-maximum (FWHM), respectively. For comparison, a small reference detector, consisting of a 3 × 3 × 5 mm(3) LSO:Ce,0.2%Ca crystal coupled to a single pixel of a dSiPM array, was measured to have a CRT as low as 120 ps FWHM. The results of this work indicate that the influence of the optical transport of the scintillation photons on the timing performance of monolithic scintillator detectors can at least partially be corrected for by utilizing the information contained in the spatio-temporal distribution of the collection of time stamps registered per scintillation event. PMID:23611889

  8. Data-Driven Exploration of the Ionization-Phonon Partitioning in Scintillating Radiation Detector Materials

    Microsoft Academic Search

    Kim F. Ferris; Bobbie-Jo M. Webb-Robertson; David V. Jordan; Dumont M. Jones

    2008-01-01

    An information-based approach to scintillating materials development has been applied to ranking the alkali halide and alkaline earth halide series in terms of their energy conversion efficiency. The efficiency of scintillating radiation detection materials can be viewed as the product of a consecutive series of electronic processes (energy conversion, transfer, and luminescence) as outlined by Lempicki and others. Relevant data

  9. Double Chooz: optimizing the sensitivity to ?13 with a multi-detector setup

    NASA Astrophysics Data System (ADS)

    Novella, P.; Double Chooz Collaboration

    2012-08-01

    The best upper limit to the neutrino mixing angle ?13 is set by the CHOOZ experiment. The eventual measurement of ?13 in reactor neutrino experiments relies on a reduction of the CHOOZ systematics of about 1 order of magnitude, along with a major increase of the luminosity. Provided that enough statistics are achieved, fighting the systematics becomes the key towards ?13. The Double Chooz experiment engages this fight with a multi-detector set up.

  10. Effect of x-ray incident direction and scintillator layer design on image quality of indirect-conversion flat-panel detector with GOS phosphor

    NASA Astrophysics Data System (ADS)

    Sato, K.; Nariyuki, F.; Nomura, H.; Takasu, A.; Fukui, S.; Nakatsu, M.; Okada, Y.; Nabeta, T.; Hosoi, Y.

    2011-03-01

    In this study, we characterized the image quality of two types of indirect-conversion flat-panel detectors: an X-ray incident-side photo-detection system (IS) and an X-ray penetration-side photo-detection system (PS). These detectors consist of a Gd2O2S:Tb (GOS) scintillator coupled with a photodiode thin film transistor (PD-TFT) array on a glass substrate. The detectors have different X-ray incident directions, glass substrates, and scintillators. We also characterized the effects of layered scintillator structures on the image quality by using a single-layered scintillator containing large phosphor grains and a double-layered scintillator consisting of a layer of large phosphor grains and a layer of small phosphor grains. The IS system consistently demonstrated a higher MTF than the PS system for a scintillator of the same thickness. Moreover, the IS system showed a higher DQE than the PS system when a thick scintillator was used. While the double-layered scintillators were useful for improving the MTF in both systems, a thick single-layered scintillator was preferable for obtaining a high DQE when the IS system was applied. These results indicate that an IS system can efficiently utilize the light emitted from the phosphor at the far side of the PD without the occurrence of blurring. The use of IS systems makes it possible to increase the thickness of the scintillator layer for improving the sensitivity without reducing the MTF, which increases the DQE. The DQE of the IS system was 1.2 times that of the PS system, despite the absorption of X-rays at the glass substrate before entering the phosphor.

  11. Evaluation of flow cell detector configurations combining simultaneous preconcentration and scintillation detection for monitoring of pertechnetate in aqueous media.

    PubMed

    Hughes, Lara D; DeVol, Timothy A

    2006-04-01

    Flow cell detectors were developed for simultaneous concentration and scintillation detection of technetium-99 in water. Evaluated flow cell geometries consisted of a coil and a fountain flow cell design; the latter is based on radial solution flow through a resin bed interfaced with a photomultiplier tube through a polycarbonate window. The sorptive scintillating media investigated were (1) an extractive scintillator combining a porous polystyrene resin with the extractant Aliquat-336 and fluor 2-(1-naphthyl)-5-phenyloxazole, (2) a mixed bed of organic scintillator (BC-400) and Tc-selective resin (TEVA), and (3) a mixed bed of inorganic scintillator particles (CaF2-Eu) with either TEVA resin or strong base anion-exchange resin (Dowex 1 x 8-400(Cl)). Depending on flow cell geometry and medium, the detection efficiencies for 99Tc ranged from 7.26 (BC-400/TEVA in coil geometry) to 50.20% (CaF2(Eu)/Dowex 1 x 8-400(Cl) in fountain flow cell geometry). The configuration with the highest sensitivity, CaF2(Eu)/Dowex 1 x 8-400(Cl) in coil geometry, can detect 99Tc as low as 3.78 Bq L(-1) for a 100-s count interval and a 200-mL sample, which is below the current regulatory level of 33 Bq L(-1). The issue of sensor reusability was addressed in this research, and its potential application at near neutral pH was demonstrated. The optimal sensor design was evaluated with a 99Tc-spiked synthetic groundwater matrix. PMID:16579605

  12. Feasibility Study of a Portable Coupled 3He Detector with LaBr 3 Gamma Scintillator for Field Identification and Quantification of Nuclear Material

    E-print Network

    Strohmeyer, Daniel C.

    2010-07-14

    and quantifying Pu in field samples. This detector consists of a plastic scintillator containing LaBr 3 nanoparticles and a polyethylene slab containing four 3He tube detectors. The system was tested via simulation with MCNPX for four Pu samples of known quality...

  13. 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.

  14. Determination of neutrino incoming direction in the CHOOZ experiment and its application to supernova explosion location by scintillator detectors

    NASA Astrophysics Data System (ADS)

    Apollonio, M.; Baldini, A.; Bemporad, C.; Caffau, E.; Cei, F.; Déclais, Y.; de Kerret, H.; Dieterle, B.; Etenko, A.; Foresti, L.; George, J.; Giannini, G.; Grassi, M.; Kozlov, Y.; Kropp, W.; Kryn, D.; Laiman, M.; Lane, C. E.; Lefièvre, B.; Machulin, I.; Martemyanov, A.; Martemyanov, V.; Mikaelyan, L.; Nicolò, D.; Obolensky, M.; Pazzi, R.; Pieri, G.; Price, L.; Riley, S.; Reeder, R.; Sabelnikov, A.; Santin, G.; Skorokhvatov, M.; Sobel, H.; Steele, J.; Steinberg, R.; Sukhotin, S.; Tomshaw, S.; Veron, D.; Vyrodov, V.

    2000-01-01

    The CHOOZ experiment has measured the antineutrino flux at about 1 km from two nuclear reactors to search for possible ?¯e-->?¯x oscillations with mass-squared differences as low as 10-3 eV2 for full mixing. We show that the analysis of the ~2700 ?¯e events, collected by our liquid scintillation detector, locates the antineutrino source within a cone of half-aperture ~18° at the 68 % C.L. We discuss the implications of this result for locating a supernova explosion.

  15. A scintillator-based online detector for the angularly resolved measurement of laser-accelerated proton spectra

    SciTech Connect

    Metzkes, J.; Kraft, S. D.; Sobiella, M.; Stiller, N.; Zeil, K.; Schramm, U. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Karsch, L.; Schuerer, M. [OncoRay - National Center for Radiation Research in Oncology, TU Dresden, Fetscherstr. 74, 01307 Dresden (Germany); Pawelke, J.; Richter, C. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); OncoRay - National Center for Radiation Research in Oncology, TU Dresden, Fetscherstr. 74, 01307 Dresden (Germany)

    2012-12-15

    In recent years, a new generation of high repetition rate ({approx}10 Hz), high power ({approx}100 TW) laser systems has stimulated intense research on laser-driven sources for fast protons. Considering experimental instrumentation, this development requires online diagnostics for protons to be added to the established offline detection tools such as solid state track detectors or radiochromic films. In this article, we present the design and characterization of a scintillator-based online detector that gives access to the angularly resolved proton distribution along one spatial dimension and resolves 10 different proton energy ranges. Conceived as an online detector for key parameters in laser-proton acceleration, such as the maximum proton energy and the angular distribution, the detector features a spatial resolution of {approx}1.3 mm and a spectral resolution better than 1.5 MeV for a maximum proton energy above 12 MeV in the current design. Regarding its areas of application, we consider the detector a useful complement to radiochromic films and Thomson parabola spectrometers, capable to give immediate feedback on the experimental performance. The detector was characterized at an electrostatic Van de Graaff tandetron accelerator and tested in a laser-proton acceleration experiment, proving its suitability as a diagnostic device for laser-accelerated protons.

  16. A scintillator-based online detector for the angularly resolved measurement of laser-accelerated proton spectra.

    PubMed

    Metzkes, J; Karsch, L; Kraft, S D; Pawelke, J; Richter, C; Schürer, M; Sobiella, M; Stiller, N; Zeil, K; Schramm, U

    2012-12-01

    In recent years, a new generation of high repetition rate (~10 Hz), high power (~100 TW) laser systems has stimulated intense research on laser-driven sources for fast protons. Considering experimental instrumentation, this development requires online diagnostics for protons to be added to the established offline detection tools such as solid state track detectors or radiochromic films. In this article, we present the design and characterization of a scintillator-based online detector that gives access to the angularly resolved proton distribution along one spatial dimension and resolves 10 different proton energy ranges. Conceived as an online detector for key parameters in laser-proton acceleration, such as the maximum proton energy and the angular distribution, the detector features a spatial resolution of ~1.3 mm and a spectral resolution better than 1.5 MeV for a maximum proton energy above 12 MeV in the current design. Regarding its areas of application, we consider the detector a useful complement to radiochromic films and Thomson parabola spectrometers, capable to give immediate feedback on the experimental performance. The detector was characterized at an electrostatic Van de Graaff tandetron accelerator and tested in a laser-proton acceleration experiment, proving its suitability as a diagnostic device for laser-accelerated protons. PMID:23277976

  17. Extraordinary improvement in scintillation detectors via post-processing with ASEDRA: solution to a 50-year-old problem

    NASA Astrophysics Data System (ADS)

    LaVigne, E.; Sjoden, G.; Baciak, J., Jr.; Detwiler, R.

    2008-04-01

    We have developed a ground-breaking algorithm, ASEDRA, to post-process scintillator detector spectra to render photopeaks with high accuracy. The post-processed spectrum is comparable with resolved full energy peaks rendered by high resolution HPGe semiconductor detectors. ASEDRA, or "Advanced Synthetically Enhanced Detector Resolution Algorithm," is currently applied to NaI(Tl) detectors, which are robust, but suffer from poor energy resolution. ASEDRA rapidly post-processes a NaI(Tl) detector spectrum over a few seconds on a standard laptop without prior knowledge of sources or spectrum features. ASEDRA incorporates a novel denoising algorithm based on an adaptive Chi-square methodology called ACHIP, or "Adaptive Chi-quare Processed denoising." Application of ACHIP is necessary to remove stochastic noise, yet preserve fine detail, and can be used as an independent tool for general noise reduction. Following noise removal, ASEDRA sequentially employs an adaptive detector response algorithm to remove the spectrum attributed to specific gammas. Tests conducted using a 2"×2" NaI(Tl) detector, along with a HPGe detector demonstrate the accuracy of ASEDRA; in this paper, we present results using a 152Eu source. Analysis of ASEDRA results show correct identification of at least 15 photopeaks from 152Eu, with relative yield ratios of major lines to better than a factor of two for most cases (referencing the 152Eu 344 keV photopeak), enabling better than a factor of four improvement in resolving peaks compared with unprocessed NaI(Tl). Moreover, denoising and synthetic resolution enhancement algorithms can be adapted to any detector. ACHIP and ASEDRA are covered under a Provisional Patent, Registration Number #60/971,770, 9/12/2007, USPTO.

  18. Resarch investigation on dense scintillation glass for use in total absorption nuclear cascade detectors

    NASA Technical Reports Server (NTRS)

    Hensler, J. R.

    1973-01-01

    Three approaches to the development of a high density scintillation glass were investigated: They include the increase of density of glass systems containing cerium - the only systems which were known to show scintillation, the testing of a novel silicate glass system containing significant concentrations of silver produced by ion exchange and never tested previously, and the hot pressing of a diphasic compact of low density scintillation glass with high density passive glass. In first two cases, while ultraviolet excited fluorescence was maintained in the glasses showing high density, scintillation response to high energy particles was not retained in the case of the cerium containing glasses or developed in the case of the silver containing glasses. In the case of the compacts, the extremely long path length caused by the multiple internal reflections which occur in such a body resulted in attenuation even with glasses of high specific transmission. It is not clear why the scintillation efficiency is not maintained in the higher density cerium containing glasses.

  19. Radiation detector developments in medical applications: inorganic scintillators in positron emission tomography.

    PubMed

    van Eijk, Carel W E

    2008-01-01

    In recent years, a number of new gamma-ray scintillators are commercially available. These scintillators are either derived from known scintillators, e.g. Lu1-xYxAlO3: Ce (LuYAP) from LuAlO3:Ce and Lu(2(1-x))Y2xSiO5:Ce (LYSO) from Lu2SiO5:Ce or are the result of new discoveries, e.g. LaCl3:Ce and LaBr3:Ce. The first two materials are primarily of interest because of the relatively high detection efficiency and fast response; LYSO has found application in time-of-flight (TOF) positron-emission tomography (TOF PET) and the LuYAP-LYSO combination is used in small-animal PET. The halide scintillators have an excellent energy resolution of approximately 3% at 662 keV and they have a relatively high light yield. LaBr3:Ce is being studied for application in TOF PET. At the same time, the search for and research on new scintillator materials are going on. For example, LuI3:Ce is a new material with a very high light yield (approximately 90,000 photons MeV(-1)). Other examples of new materials are (C6H13NH3)2PbI4 and (C3H7NH3)2PbBr4, organic-inorganic hybrid compounds, of which the former has a very fast sub-nanosecond response. The new scintillators show great promise for new developments in medical applications, in particular, for PET systems. PMID:18321877

  20. The scintillating fiber detectors of the H1 forward proton spectrometer

    NASA Astrophysics Data System (ADS)

    Bähr, J.; Harder, U.; Hiller, K.; Lüdecke, H.; Nahnhauer, R.

    1998-11-01

    Since 1995 the H1 experiment at HERA is operating a Forward Proton Spectrometer (FPS) employing the HERA machine magnets adjacent to the interaction zone as spectrometer magnets. The FPS consists of four stations, two vertical stations and two horizontal stations. Scattered protons are detected in pairs of stations behind the interaction point with scintillating fiber hodoscopes. The scintillating fibers are readout by Position-Sensitive Photomultipliers (PSPM) in the case of the vertical stations and by Micro-Channel Photomultipliers (MCPM) for the horizontal stations.

  1. Development of cryogenic phonon detectors based on CaMoO4 and ZnWO4 scintillating crystals for direct dark matter search experiments

    E-print Network

    I. Bavykina; G. Angloher; D. Hauff; M. Kiefer; F. Petricca; F. Proebst

    2008-11-12

    This work reports on the development of the first phonon detectors based on CaMoO4 and ZnWO4 scintillating crystals for the CRESST-II experiment. In particular, a novel technique for the production of the ZnWO4 phonon detector with a separate thermometer carrier was investigated. The influence of the thermal and mechanical treatment on the scintillation light output of CaMoO4 and ZnWO4 crystals at room temperature is discussed.

  2. Performance Comparison of a Large Volume CZT Semiconductor Detector and a LaBr (Ce) Scintillator Detector

    Microsoft Academic Search

    Raquel González; José M. Pérez; Oscar Vela; Eduardo de Burgos

    2006-01-01

    The development of portable nuclear instrumentation demands compact high sensitivity detectors operated at room temperature. The sensitivity of these detectors mainly depends on two parameters: absolute efficiency and energy resolution. In order to provide high efficiency, large volumes are needed. For semiconductor detectors able to operate at room temperature, the largest effective volumes with acceptable resolution are achieved with CdZnTe

  3. Performance comparison of a large volume CZT semiconductor detector and a LaBr3(Ce) scintillator detector

    Microsoft Academic Search

    Raquel González; José M. Pérez; Oscar Vela; Eduardo de Burgos

    2005-01-01

    The development of portable nuclear instrumentation demands compact high sensitivity detectors operated at room temperature. The sensitivity of these detectors mainly depends on two parameters: absolute efficiency and energy resolution in the range 10-1500 keV. In order to provide high efficiency, large volumes are needed. For semiconductor detectors able to operate at room temperature, the largest effective volumes with acceptable

  4. Low-energy neutron detector based upon lithium lanthanide borate scintillators

    DOEpatents

    Czirr, John B. (Mapleton, UT)

    1998-01-01

    An apparatus for detecting neutrons includes a cerium activated scintillation crystal containing .sup.10 B, with the scintillation crystal emitting light in response to .alpha. particles emitted from the .sup.10 B(n,.alpha.)Li* reaction. The apparatus also includes a gamma scintillator positioned adjacent the crystal and which generates light in response to gamma rays emitted from the decay of Li*. The apparatus further includes a first and a second light-to-electronic signal converter each positioned to respectively receive light from the crystal and the gamma scintillator, and each respectively outputting first and second electronic signals representative of .alpha. particles from the .sup.10 B(n,.alpha.)Li* reaction and gamma rays from the .sup.10 B(n,.alpha.)Li* reaction. The apparatus includes a coincidence circuit connected to receive the first and second signals and which generates a coincidence signal when the first and second signals coincide. The apparatus also includes a data analyzer for receiving an additional signal from at least one of the first and second converters, and for operating in response to the coincidence signal.

  5. A count-rate model for PET scanners using pixelated Anger-logic detectors with different scintillators

    NASA Astrophysics Data System (ADS)

    Surti, S.; Karp, J. S.

    2005-12-01

    A high count-rate simulation (HCRSim) model has been developed so that all results are derived from fundamental physics principles. Originally developed to study the behaviour of continuous sodium iodide (NaI(Tl)) detectors, this model is now applied to PET scanners based on pixelated Anger-logic detectors using lanthanum bromide (LaBr3), gadolinium orthosilicate (GSO) and lutetium orthosilicate (LSO) scintillators. This simulation has been used to study the effect on scanner deadtime and pulse pileup at high activity levels due to the scintillator stopping power (?), decay time (?) and energy resolution. Simulations were performed for a uniform 20 cm diameter × 70 cm long cylinder (NEMA NU2-2001 standard) in a whole-body scanner with an 85 cm ring diameter and a 25 cm axial field-of-view. Our results for these whole-body scanners demonstrate the potential of a pixelated Anger-logic detector and the relationship of its performance with the scanner NEC rate. Faster signal decay and short coincidence timing window lead to a reduction in deadtime and randoms fraction in the LaBr3 and LSO scanners compared to GSO. The excellent energy resolution of LaBr3 leads to the lowest scatter fraction for all scanners and helps compensate for reduced sensitivity compared to the GSO and LSO scanners, leading to the highest NEC values at high activity concentrations. The LSO scanner has the highest sensitivity of all the scanner designs investigated here, therefore leading to the highest peak NEC value but at a lower activity concentration than that of LaBr3.

  6. Comparison of a LaBr3 (Ce) Scintillation Detector With a Large Volume CdZnTe Detector

    Microsoft Academic Search

    Agnieszka Syntfeld; Rolf Arlt; Vladimir Gostilo; Alexander Loupilov; Marek Moszyski; Antoni Nassalski; Martha Swoboda; Dariusz Wolski

    2006-01-01

    The performance of hand-held radioisotope identification devices (RIDs) is still hampered by the performance of the NaI(Tl) detectors, which are commonly used in such instruments. In this paper, we continue the search for better detector options. One of the largest single elements ever made, a coplanar CdZnTe (CZT) detector (30times15times12.1 mm3 volume 5.45 cm3 designed by University of Michigan) is

  7. Energy resolution of scintillation detectors readout with large area avalanche photodiodes and photomultipliers

    Microsoft Academic Search

    M. Moszynski; M. Kapusta; D. Wolski; M. Szawlowski; W. Klamra

    1998-01-01

    The energy resolution of small NaI(Tl), CsI(Tl), BGO, GSO, YAP and LSO crystals has been studied using 16 mm diameter large area avalanche photodiodes (LAAPD) and a 52 mm diameter photomultiplier. The best result of 4.8% for 662 keV ?-rays from a 137Cs source was obtained with a 9 mm in diameter by 9 mm high CsI(Tl) scintillator coupled to

  8. Single electron response of the scintillator-light guide-photomultiplier detector.

    PubMed

    Novák, L; Müllerová, I

    2009-01-01

    The time response of a scintillator-light guide-photomultiplier combination was measured with a time-constant of 3 ns. Single detected electrons were recognizable at the output of the photomultiplier. The distribution of the number of photoelectrons produced by one detected electron and the pulse-height distribution of the photomultiplier output pulses were analysed. Statistical noise computed from these distributions was compared with the noise produced by the dark current of the photomultiplier. PMID:19196414

  9. Cone beam breast CT with a high pitch (75 ?m), thick (500 ?m) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

    SciTech Connect

    Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C. [Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030 (United States)] [Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030 (United States)

    2013-10-15

    Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 ?m), thick (500 ?m) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer).Methods: Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 ?m), thin (150 ?m) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 ?m), thick (600 ?m) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used.Results: The authors have demonstrated that the use of a high pitch (75 ?m) CMOS detector coupled with a thick (500 ?m) CsI scintillator helped make the smaller 150–160, 160–180, and 180–200 ?m MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200–212 and 212–224 ?m MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224–250 ?m or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160–180 ?m MCs as compared to 28% visibility achieved by the low pitch (194 ?m) aSi/CsI flat panel detector. The measurements confirm that the Hamamatsu detector has the highest MTF, followed by the Dexel detector, and then the Varian detector. However, the Dexela detector, with its thick (500 ?m) CsI scintillator and low noise level, has the highest DQE at all frequencies, followed by the Varian detector, and then the Hamamatsu detector. The findings on the MC visibility correlated well with the differences in MTFs, noise power spectra, and DQEs measured for these three detectors.Conclusions: The authors have demonstrated that the use of the CMOS type Dexela detector with its high pitch (75 ?m) and thick (500 ?m) CsI scintillator could help improve the MC visibility. However, the improvement depended on the exposure level and the MC size. For imaging larger MCs or scanning at high exposure levels, there was little advantage in using the Dexela detector as compared to the aSi type Varian detector. These findings correlate well with the higher measured DQEs of the Dexela detector, especially at higher frequencies.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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. We used a complete clinical OARtrac system including the PSD probes, charge coupled device 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 matched fields to a maximum dose of 200 cGy in a 100 cm source-axis distance 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.

  11. 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

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

    PubMed

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

    2014-05-01

    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. We used a complete clinical OARtrac system including the PSD probes, charge coupled device 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 matched fields to a maximum dose of 200 cGy in a 100 cm source-axis distance 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

  13. 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

  14. 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.

  15. A detector insert based on continuous scintillators for hybrid MR-PET imaging of the human brain

    NASA Astrophysics Data System (ADS)

    Rato Mendes, P.; Cuerdo, R.; Sarasola, I.; García de Acilu, P.; Navarrete, J.; Vela, O.; Oller, J. C.; Cela, J. M.; Núñez, L.; Pastrana, M.; Romero, L.; Willmott, C.

    2013-02-01

    We are developing a positron emission tomography (PET) insert for existing magnetic resonance (MR) equipment, aiming at hybrid MR-PET imaging. Our detector block design is based on trapezoid-shaped LYSO:Ce monolithic scintillators coupled to magnetically compatible Hamamatsu S8550-02 silicon avalanche photodiode (APD) matrices with a dedicated ASIC front-end readout from GammaMedica-Ideas (Fornebu, Norway). The detectors are position sensitive, capable of determining the incidence point of 511 keV gammas with an intrinsic spatial resolution on the order of 2 mm by means of supervised learning neural-network (NN) algorithms. These algorithms, apart from providing continuous coordinates, are also intrinsically corrected for depth of interaction effects and thus parallax-free. Recently we have implemented an advanced prototype featuring two heads with four detector blocks each and final front-end and readout electronics, improving the spatial resolution of reconstructed point source images down to 1.7 mm full width at half maximum (FWHM). Presently we are carrying out operational tests of components and systems under magnetic fields using a 3 T MR scanner. In this paper we present a description of our project, a summary of the results obtained with laboratory prototypes, and the strategy to build and install the complete system at the nuclear medicine department of a collaborating hospital.

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

    PubMed

    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. PMID:24434775

  17. Implementation of gamma-ray spectrometry in two real-time water monitors using NaI(Tl) scintillation detectors.

    PubMed

    Casanovas, R; Morant, J J; Salvadó, M

    2013-10-01

    In this study, the implementation of gamma-ray spectrometry in two real-time water monitors using 2 in. × 2 in. NaI(Tl) scintillation detectors is described. These monitors collect the water from the river through a pump and it is analyzed in a vessel, which is shielded with Pb. The full calibration of the monitors was performed experimentally, except for the efficiency curve, which was set using validated Monte Carlo simulations with the EGS5 code system. After the calibration, the monitors permitted the identification and quantification of the involved isotopes in a possible radioactive increment and made it possible to discard possible leaks in the nuclear plants. As an example, a radiological increment during rain is used to show the advantages of gamma-ray spectrometry. To study the capabilities of the monitor, the minimum detectable activity concentrations for (131)I, (137)Cs and (40)K are presented for different integration times. PMID:23827508

  18. Plastic scintillator detectors for the study of transfer and breakup reactions at intermediate energies

    SciTech Connect

    Schmidt, H.R.; Bantel, M.; Chan, Y.D.; Gazes, S.M.; Kamermans, R.; Albiston, C.; Wald, S.; Stokstad, R.G.

    1984-10-01

    The detection of light particles associated with projectile like fragments can be used to separate transfer and breakup reactions provided the detectors cover a large solid angle. Three detection systems are described: (1) a ..pi.. detector in the shape of a cube, 20 cm on a side, (2) a X-Y position sensitive ..delta..E-E detector having an area of 20 x 20 cm/sup 2/, and (3) a multi-element detector consisting of eight position sensitive strips. The latter two detectors are of the phoswich type having the thin element of NE102 (tau = 2.5 ns) and the thick element of NE115 (tau = 225 ns). The performance characteristics of the three detectors are described. 6 references, 13 figures.

  19. Further study of CdWO4 crystal scintillators as detectors for high sensitivity double beta experiments: scintillation properties and pulse-shape discrimination

    E-print Network

    L. Bardelli; M. Bini; P. G. Bizzeti; L. Carraresi; F. A. Danevich; T. F. Fazzini; B. V. Grinyov; N. V. Ivannikova; V. V. Kobychev; B. N. Kropivyansky; P. R. Maurenzig; L. L. Nagornaya; S. S. Nagorny; A. S. Nikolaiko; A. A. Pavlyuk; D. V. Poda; I. M. Solsky; M. V. Sopinskyy; Yu. G. Stenin; F. Taccetti; V. I. Tretyak; Ya. V. Vasiliev; S. S. Yurchenko

    2006-08-02

    Energy resolution, light yield, non-proportionality in the scintillation response, alpha/beta ratio, pulse shape for gamma rays and alpha particles were studied with CdWO4 crystal scintillators. Some indication for a difference in the emission spectra for gamma rays and alpha particles was observed. No dependence of CdWO4 pulse shape on emission spectrum wavelengths under laser, alpha particles and gamma ray excitation was observed. Dependence of scintillation pulse shape for gamma quanta and alpha particles and pulse-shape discrimination ability on temperature was measured in the range of 0-24 degrees.

  20. Spectral modeling of scintillator for the NEMO-3 and SuperNEMO detectors

    E-print Network

    J. Argyriades; R. Arnold; C. Augier; J. Baker; A. S. Barabash; M. Bongrand; G. Broudin-Bay; V. B. Brudanin; A. J. Caffrey; S. Cebrián; A. Chapon; E. Chauveau; Th. Dafni; Z. Daraktchieva; J. D iaz; D. Durand; V. G. Egorov; J. J. Evans; N. Fatemi-Ghomi; R. Flack; A. Basharina-Freshville; K-I. Fushimi; X. Garrido; H. Gómez; B. Guillon; A. Holin; K. Holy; J. J. Horkey; Ph. Hubert; C. Hugon; F. J. Iguaz; I. G. Irastorza; N. Ishihara; C. M. Jackson; S. Jullian; S. Kanamaru; M. Kauer; O. I. Kochetov; S. I. Konovalov; V. E. Kovalenko; D. Lalanne; K. Lang; Y. Lemi ere; G. Lutter; G. Luzón; F. Mamedov; Ch. Marquet; J. Martin-Albo; F. Mauger; F. Monrabal; A. Nachab; I. Nasteva; I. B. Nemchenok; C. H. Nguyen; F. Nova; P. Novella; H. Ohsumi; R. B. Pahlka; F. Perrot; F. Piquemal; P. P. Povinec; B. Richards; J. S. Ricol; C. L. Riddle; A. Rodriguez; R. Saakyan; X. Sarazin; J. K. Sedgbeer; L. Serra; L. Simard; F. Šimkovic; Yu. A. Shitov; A. A. Smolnikov; S. Soldner-Rembold; I. Štekl; Y. Sugaya; C. S. Sutton; G. Szklarz; Y. Tamagawa; J. Thomas; R. Thompson; V. V. Timkin; V. I. Tretyak; Vl. I. Tretyak; V. I. Umatov; L. V ala; I. A. Vanyushin; R. Vasiliev; V. Vorobel; Ts. Vylov; D. Waters; N. Yahlali; A. Žukauskas

    2010-11-08

    We have constructed a GEANT4-based detailed software model of photon transport in plastic scintillator blocks and have used it to study the NEMO-3 and SuperNEMO calorimeters employed in experiments designed to search for neutrinoless double beta decay. We compare our simulations to measurements using conversion electrons from a calibration source of $\\rm ^{207}Bi$ and show that the agreement is improved if wavelength-dependent properties of the calorimeter are taken into account. In this article, we briefly describe our modeling approach and results of our studies.

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

    SciTech Connect

    Therriault-Proulx, Francois [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and Departement de Physique, de Genie Physique et d'Optique and Centre de Recherche en Cancerologie de l'Universite Laval Universite Laval, Quebec, Quebec G1V 0A6 (Canada); Beddar, Sam [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); Beaulieu, Luc [Departement de Physique, de Genie Physique et d'Optique and Centre de Recherche en Cancerologie de l'Universite Laval Universite Laval, Quebec, Quebec G1V 0A6, Canada and Departement de Radio-Oncologie and Centre de Recherche du CHU de Quebec, CHU de Quebec, Quebec G1R 2J6 (Canada)

    2013-06-15

    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 {sup 192}Ir 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.

  2. 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

  3. The sensitivity of LaBr3:Ce scintillation detectors to low energy neutrons: Measurement and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Tain, J. L.; Agramunt, J.; Algora, A.; Aprahamian, A.; Cano-Ott, D.; Fraile, L. M.; Guerrero, C.; Jordan, M. D.; Mach, H.; Martinez, T.; Mendoza, E.; Mosconi, M.; Nolte, R.

    2015-02-01

    The neutron sensitivity of a cylindrical ?1.5 in.×1.5 in. LaBr3:Ce scintillation detector was measured using quasi-monoenergetic neutron beams in the energy range from 40 keV to 2.5 MeV. In this energy range the detector is sensitive to ?-rays generated in neutron inelastic and capture processes. The experimental energy response was compared with Monte Carlo simulations performed with the Geant4 simulation toolkit using the so-called High Precision Neutron Models. These models rely on relevant information stored in evaluated nuclear data libraries. The performance of the Geant4 Neutron Data Library as well as several standard nuclear data libraries was investigated. In the latter case this was made possible by the use of a conversion tool that allowed the direct use of the data from other libraries in Geant4. Overall it was found that there was good agreement with experiment for some of the neutron data bases like ENDF/B-VII.0 or JENDL-3.3 but not with the others such as ENDF/B-VI.8 or JEFF-3.1.

  4. A Digital Method for the Discrimination of Neutrons and Rays With Organic Scintillation Detectors Using Frequency Gradient Analysis

    Microsoft Academic Search

    Guofu Liu; Malcolm J. Joyce; Xiandong Ma; Michael D. Aspinall

    2010-01-01

    A digital method for the discrimination of neutron and ?-ray events from an organic scintillator has been investigated by using frequency gradient analysis (FGA) based on the Fourier transform. Since the scintillation process and the photomultiplier tube (PMT) anode signal are often very noisy, most pulse-shape discrimination methods in a scintillation detection system (e.g., the charge comparison (CC) method or

  5. ScintSim1: A new Monte Carlo simulation code for transport of optical photons in 2D arrays of scintillation detectors

    PubMed Central

    Mosleh-Shirazi, Mohammad Amin; Zarrini-Monfared, Zinat; Karbasi, Sareh; Zamani, Ali

    2014-01-01

    Two-dimensional (2D) arrays of thick segmented scintillators are of interest as X-ray detectors for both 2D and 3D image-guided radiotherapy (IGRT). Their detection process involves ionizing radiation energy deposition followed by production and transport of optical photons. Only a very limited number of optical Monte Carlo simulation models exist, which has limited the number of modeling studies that have considered both stages of the detection process. We present ScintSim1, an in-house optical Monte Carlo simulation code for 2D arrays of scintillation crystals, developed in the MATLAB programming environment. The code was rewritten and revised based on an existing program for single-element detectors, with the additional capability to model 2D arrays of elements with configurable dimensions, material, etc., The code generates and follows each optical photon history through the detector element (and, in case of cross-talk, the surrounding ones) until it reaches a configurable receptor, or is attenuated. The new model was verified by testing against relevant theoretically known behaviors or quantities and the results of a validated single-element model. For both sets of comparisons, the discrepancies in the calculated quantities were all <1%. The results validate the accuracy of the new code, which is a useful tool in scintillation detector optimization. PMID:24600168

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

    SciTech Connect

    Therriault-Proulx, Francois; Beddar, Sam; Briere, Tina M.; Archambault, Louis; Beaulieu, Luc [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, Texas 77030 (United States) and Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Department of Radiation Physics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, Texas 77030 (United States); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Ho circumflex tel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec, Quebec G1R 2J6 (Canada)

    2011-04-15

    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.

  7. Direct observation of avalanche scintillations in a THGEM-based two-phase Ar avalanche detector using Geiger-mode APD

    NASA Astrophysics Data System (ADS)

    Bondar, A.; Buzulutskov, A.; Grebenuk, A.; Sokolov, A.; Akimov, D.; Alexandrov, I.; Breskin, A.

    2010-08-01

    A novel concept of optical signal recording in cryogenic two-phase avalanche detectors, with Geiger-mode Avalanche Photodiodes (G-APD) measuring avalanche-scintillation photons in a thick Gas Electron Multiplier (THGEM), has been studied in view of its potential applications in rare-event experiments. The effective detection of avalanche scintillations in THGEM holes has been demonstrated in two-phase Ar with a bare G-APD without wavelength shifter, i.e. insensitive to VUV emission of Ar. At gas-avalanche gain of 400 and under ±70° viewing-angle, the G-APD yielded 640 photoelectrons (pe) per 60 keV X-ray converted in liquid Ar; this corresponds to 0.7 pe per initial (prior to multiplication) electron. The avalanche-scintillation light yield measured by the G-APD was about 0.7 pe per avalanche electron, extrapolated to 4? acceptance. The avalanche scintillations observed occurred presumably in the near infrared (NIR) where G-APDs may have high sensitivity. The measured scintillation yield is similar to that observed by others in the VUV. Other related topics discussed in this work are the G-APD's single-pixel and quenching resistor characteristics at cryogenic temperatures.

  8. Application of the anti-Compton detector in neutron activation analysis techniques

    NASA Astrophysics Data System (ADS)

    Gierlik, M.; Borsuk, S.; Guzik, Z.; Iwanowska, J.; Ka?mierczak, ?.; Korolczuk, S.; Koz?owski, T.; Krakowski, T.; Marcinkowski, R.; Swiderski, L.; Szeptycka, M.; Szewi?ski, J.; Urban, A.

    2015-07-01

    In this work we report about performance of the cylindrical 3 in.×3 in. LaBr3 scintillation detector assembled with a BGO guard detector. This setup was optimized for the identification of explosive materials by means of fast neutron activation analysis.

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

    SciTech Connect

    Wang, Lilie L. W.; Beddar, Sam [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2011-03-15

    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 10x10 down to 0.5x0.5 cm{sup 2} 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 0.5x0.5 cm{sup 2} 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 10x10 to 0.5x0.5 cm{sup 2}, 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.

  10. Verification of proton range, position, and intensity in IMPT with a 3D liquid scintillator detector system

    SciTech Connect

    Archambault, L.; Poenisch, F.; Sahoo, N.; Robertson, D.; Lee, A.; Gillin, M. T.; Mohan, R.; Beddar, S. [Departments of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030 (United States); Departments of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030 (United States); Departments of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030 (United States)

    2012-03-15

    Purpose: Intensity-modulated proton therapy (IMPT) using spot scanned proton beams relies on the delivery of a large number of beamlets to shape the dose distribution in a highly conformal manner. The authors have developed a 3D system based on liquid scintillator to measure the spatial location, intensity, and depth of penetration (energy) of the proton beamlets in near real-time. Methods: The detector system consists of a 20 x 20 x 20 cc liquid scintillator (LS) material in a light tight enclosure connected to a CCD camera. This camera has a field of view of 25.7 by 19.3 cm and a pixel size of 0.4 mm. While the LS is irradiated, the camera continuously acquires images of the light distribution produced inside the LS. Irradiations were made with proton pencil beams produced with a spot-scanning nozzle. Pencil beams with nominal ranges in water between 9.5 and 17.6 cm were scanned to irradiate an area of 10 x 10 cm square on the surface of the LS phantom. Image frames were acquired at 50 ms per frame. Results: The signal to noise ratio of a typical Bragg peak was about 170. Proton range measured from the light distribution produced in the LS was accurate to within 0.3 mm on average. The largest deviation seen between the nominal and measured range was 0.6 mm. Lateral position of the measured pencil beam was accurate to within 0.4 mm on average. The largest deviation seen between the nominal and measured lateral position was 0.8 mm; however, the accuracy of this measurement could be improved by correcting light scattering artifacts. Intensity of single proton spots were measured with precision ranging from 3 % for the smallest spot intensity (0.005 MU) to 0.5 % for the largest spot (0.04 MU). Conclusions: Our LS detector system has been shown to be capable of fast, submillimeter spatial localization of proton spots delivered in a 3D volume. This system could be used for beam range, intensity and position verification in IMPT.

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

    PubMed Central

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

    2010-01-01

    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 cm3 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 0.5×0.5 to 10×10 cm2. 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 2.0×2.0 cm2 and above. At smaller field sizes, the PSD obtained output factors as much as 15% higher than those found using the ionization chamber by 0.6×0.6 cm2 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. Conclusions: The authors’ results suggest that PSDs provide a useful and possibly superior alternative to existing dosimetry systems for small fields, as they are inherently less susceptible to volume-averaging and perturbation effects than larger, air-filled ionization chambers. Therefore, PSDs may provide more accurate small-field output factor determination, regardless of the collimation mechanism. PMID:21089789

  12. Verification of proton range, position, and intensity in IMPT with a 3D liquid scintillator detector system

    PubMed Central

    Archambault, L.; Poenisch, F.; Sahoo, N.; Robertson, D.; Lee, A.; Gillin, M. T.; Mohan, R.; Beddar, S.

    2012-01-01

    Purpose: Intensity-modulated proton therapy (IMPT) using spot scanned proton beams relies on the delivery of a large number of beamlets to shape the dose distribution in a highly conformal manner. The authors have developed a 3D system based on liquid scintillator to measure the spatial location, intensity, and depth of penetration (energy) of the proton beamlets in near real-time. Methods: The detector system consists of a 20?×?20?×?20 cc liquid scintillator (LS) material in a light tight enclosure connected to a CCD camera. This camera has a field of view of 25.7 by 19.3 cm and a pixel size of 0.4 mm. While the LS is irradiated, the camera continuously acquires images of the light distribution produced inside the LS. Irradiations were made with proton pencil beams produced with a spot-scanning nozzle. Pencil beams with nominal ranges in water between 9.5 and 17.6 cm were scanned to irradiate an area of 10?×?10 cm square on the surface of the LS phantom. Image frames were acquired at 50 ms per frame. Results: The signal to noise ratio of a typical Bragg peak was about 170. Proton range measured from the light distribution produced in the LS was accurate to within 0.3 mm on average. The largest deviation seen between the nominal and measured range was 0.6 mm. Lateral position of the measured pencil beam was accurate to within 0.4 mm on average. The largest deviation seen between the nominal and measured lateral position was 0.8 mm; however, the accuracy of this measurement could be improved by correcting light scattering artifacts. Intensity of single proton spots were measured with precision ranging from 3?% for the smallest spot intensity (0.005 MU) to 0.5?% for the largest spot (0.04 MU). Conclusions: Our LS detector system has been shown to be capable of fast, submillimeter spatial localization of proton spots delivered in a 3D volume. This system could be used for beam range, intensity and position verification in IMPT. PMID:22380355

  13. Scintillator counters with WLS fiber/MPPC readout for the side muon range detector (SMRD) of the T2K experiment

    NASA Astrophysics Data System (ADS)

    Izmaylov, A.; Aoki, S.; Blocki, J.; Brinson, J.; Dabrowska, A.; Danko, I.; Dziewiecki, M.; Ellison, B.; Golyshkin, L.; Gould, R.; Hara, T.; Hartfiel, B.; Holeczek, J.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kisiel, J.; Kozlowski, T.; Kudenko, Yu.; Kurjata, R.; Kutter, T.; Lagoda, J.; Liu, J.; Marzec, J.; Metcalf, W.; Mijakowski, P.; Mineev, O.; Musienko, Yu.; Naples, D.; Nauman, M.; Northacker, D.; Nowak, J.; Paolone, V.; Posiadala, M.; Przewlocki, P.; Reid, J.; Rondio, E.; Shaykhiev, A.; Sienkiewicz, M.; Smith, D.; Sobczyk, J.; Stodulski, M.; Straczek, A.; Sulej, R.; Suzuki, A.; Swierblewski, J.; Szeglowski, T.; Szeptycka, M.; Wachala, T.; Warner, D.; Yershov, N.; Yano, T.; Zalewska, A.; Zaremba, K.; Ziembicki, M.

    2010-11-01

    The T2K neutrino experiment at J-PARC uses a set of near detectors to measure the properties of an unoscillated neutrino beam and neutrino interaction cross-sections. One of the sub-detectors of the near-detector complex, the side muon range detector (SMRD), is described in the paper. The detector is designed to help measure the neutrino energy spectrum, to identify background and to calibrate the other detectors. The active elements of the SMRD consist of 0.7 cm thick extruded scintillator slabs inserted into air gaps of the UA1 magnet yokes. The readout of each scintillator slab is provided through a single WLS fiber embedded into a serpentine-shaped groove. Two Hamamatsu multi-pixel avalanche photodiodes (MPPC's) are coupled to both ends of the WLS fiber. This design allows us to achieve a high MIP detection efficiency of greater than 99%. A light yield of 25-50 p.e./MIP, a time resolution of about 1 ns and a spatial resolution along the slab better than 10 cm were obtained for the SMRD counters.

  14. Geant4 simulation of zinc oxide nanowires in anodized aluminum oxide template as a low energy X-ray scintillator detector

    NASA Astrophysics Data System (ADS)

    Taheri, Ali; Saramad, Shahyar; Setayeshi, Saeed

    2013-02-01

    In this work, ZnO nanowires in anodized aluminum oxide nanoporous template are proposed as an architecture for development of new generation of scintillator based X-ray imagers. The optical response of crystalline ordered ZnO nanowire arrays in porous anodized aluminum oxide template under 20 keV X-ray illumination is simulated using the Geant4 Monte Carlo code. The results show that anodized aluminum oxide template has a special impact as a light guide to conduct the optical photons induced by X-ray toward the detector thickness and to decrease the light scattering in detector volume. This inexpensive and effective method can significantly improve the spatial resolution in scintillator based X-ray imagers, especially in medical applications.

  15. Effect of crystal shape, size and reflector type on operation characteristics of gamma-radiation detectors based on CsI(Tl) and CsI(Na) scintillators

    Microsoft Academic Search

    M. E. Globus; B. V. Grinyov; M. A. Ratner

    1996-01-01

    Operation characteristics of CsI(Tl) and CsI(Na) scintillation detectors, to a large degree connected with light collection in crystals, are calculated for various shapes, sizes and reflecting surface types. Allowance is made for the true light reflection indicatrix which is characterized by the effective mirror constituent of the reflected light, p. Its value ?p?, averaged over incidence angle, is used for

  16. Rare earth ceramic scintillator

    SciTech Connect

    DiBianca, F. A.; Cusano, D. A.; Georges, J.-P. J.; Greskovich, C. D.

    1985-06-25

    An improved scintillator for a solid state radiation detector useful in CT (computed tomography), DR (digital radiography), and related technologies. The scintillator, rather than being grown as a single crystal, is formed by means of hot pressing or sintering, as a polycrystalline ceramic. Rare earth oxides doped with rare earth activators are selected to yield a cubic crystal structure of high density and transmittance, which satisfies radiation detector requirements better than crystals utilized heretofore.

  17. Achieving a Linear Dose Rate Response in Pulse-Mode Silicon Photodiode Scintillation Detectors Over a Wide Range of Excitations

    NASA Astrophysics Data System (ADS)

    Carroll, Lewis

    2014-02-01

    We are developing a new dose calibrator for nuclear pharmacies that can measure radioactivity in a vial or syringe without handling it directly or removing it from its transport shield “pig”. The calibrator's detector comprises twin opposing scintillating crystals coupled to Si photodiodes and current-amplifying trans-resistance amplifiers. Such a scheme is inherently linear with respect to dose rate over a wide range of radiation intensities, but accuracy at low activity levels may be impaired, beyond the effects of meager photon statistics, by baseline fluctuation and drift inevitably present in high-gain, current-mode photodiode amplifiers. The work described here is motivated by our desire to enhance accuracy at low excitations while maintaining linearity at high excitations. Thus, we are also evaluating a novel “pulse-mode” analog signal processing scheme that employs a linear threshold discriminator to virtually eliminate baseline fluctuation and drift. We will show the results of a side-by-side comparison of current-mode versus pulse-mode signal processing schemes, including perturbing factors affecting linearity and accuracy at very low and very high excitations. Bench testing over a wide range of excitations is done using a Poisson random pulse generator plus an LED light source to simulate excitations up to ˜106 detected counts per second without the need to handle and store large amounts of radioactive material.

  18. Monte Carlo simulation studies on scintillation detectors and image reconstruction of brain-phantom tumors in TOFPET.

    PubMed

    Mondal, Nagendra Nath

    2009-10-01

    This study presents Monte Carlo Simulation (MCS) results of detection efficiencies, spatial resolutions and resolving powers of a time-of-flight (TOF) PET detector systems. Cerium activated Lutetium Oxyorthosilicate (Lu(2)SiO(5): Ce in short LSO), Barium Fluoride (BaF(2)) and BriLanCe 380 (Cerium doped Lanthanum tri-Bromide, in short LaBr(3)) scintillation crystals are studied in view of their good time and energy resolutions and shorter decay times. The results of MCS based on GEANT show that spatial resolution, detection efficiency and resolving power of LSO are better than those of BaF(2) and LaBr(3), although it possesses inferior time and energy resolutions. Instead of the conventional position reconstruction method, newly established image reconstruction (talked about in the previous work) method is applied to produce high-tech images. Validation is a momentous step to ensure that this imaging method fulfills all purposes of motivation discussed by reconstructing images of two tumors in a brain phantom. PMID:20098551

  19. Investigation of Crystal Surface Finish and Geometry on Single LYSO Scintillator Detector Performance for Depth-of-Interaction Measurement with Silicon Photomultipliers.

    PubMed

    Bircher, Chad; Shao, Yiping

    2012-11-21

    Depth of Interaction (DOI) information can improve quality of reconstructed images acquired from Positron Emission Tomography (PET), especially in high resolution and compact scanners dedicated for breast, brain, or small animal imaging applications. Additionally, clinical scanners with time of flight capability can also benefit from DOI information. One of the most promising methods of determining DOI in a crystal involves reading the signal from two ends of a scintillation crystal, and calculating the signal ratio between the two detectors. This method is known to deliver a better DOI resolution with rough crystals compared to highly polished crystals. However, what is still not well studied is how much of a tradeoff is involved between spatial, energy, temporal, and DOI resolutions as a function of the crystal surface treatment and geometry with the use of Silicon Photomultipliers (SiPM) as the photo detectors. This study investigates the effects of different crystal surface finishes and geometries on energy, timing and DOI resolutions at different crystal depths. The results show that for LYSO scintillators of 1.5×1.5×20 mm(3) and 2×2×20 mm(3) with their surfaces finished from 0.5 to 30 micron roughness, almost the same energy and coincidence timing resolutions were maintained, around 15% and 2.4 ns respectively across different crystal depths, while the DOI resolutions were steadily improved from worse than 5 mm to better than 2 mm. They demonstrate that crystal roughness, with proper surface preparing, does not have a significant effect on the energy and coincidence timing resolutions in the crystals examined, and there does not appear to be a tradeoff between improving DOI resolution and degrading other detector performances. These results will be valuable to guide the selection of crystal surface conditions for developing a DOI measurable PET detector with a full array of LYSO scintillators coupled to SiPM arrays. PMID:23087497

  20. Investigation of Crystal Surface Finish and Geometry on Single LYSO Scintillator Detector Performance for Depth-of-Interaction Measurement with Silicon Photomultipliers

    PubMed Central

    Bircher, Chad

    2012-01-01

    Depth of Interaction (DOI) information can improve quality of reconstructed images acquired from Positron Emission Tomography (PET), especially in high resolution and compact scanners dedicated for breast, brain, or small animal imaging applications. Additionally, clinical scanners with time of flight capability can also benefit from DOI information. One of the most promising methods of determining DOI in a crystal involves reading the signal from two ends of a scintillation crystal, and calculating the signal ratio between the two detectors. This method is known to deliver a better DOI resolution with rough crystals compared to highly polished crystals. However, what is still not well studied is how much of a tradeoff is involved between spatial, energy, temporal, and DOI resolutions as a function of the crystal surface treatment and geometry with the use of Silicon Photomultipliers (SiPM) as the photo detectors. This study investigates the effects of different crystal surface finishes and geometries on energy, timing and DOI resolutions at different crystal depths. The results show that for LYSO scintillators of 1.5×1.5×20 mm3 and 2×2×20 mm3 with their surfaces finished from 0.5 to 30 micron roughness, almost the same energy and coincidence timing resolutions were maintained, around 15% and 2.4 ns respectively across different crystal depths, while the DOI resolutions were steadily improved from worse than 5 mm to better than 2 mm. They demonstrate that crystal roughness, with proper surface preparing, does not have a significant effect on the energy and coincidence timing resolutions in the crystals examined, and there does not appear to be a tradeoff between improving DOI resolution and degrading other detector performances. These results will be valuable to guide the selection of crystal surface conditions for developing a DOI measurable PET detector with a full array of LYSO scintillators coupled to SiPM arrays. PMID:23087497

  1. Investigation of crystal surface finish and geometry on single LYSO scintillator detector performance for depth-of-interaction measurement with silicon photomultipliers

    NASA Astrophysics Data System (ADS)

    Bircher, Chad; Shao, Yiping

    2012-11-01

    Depth of Interaction (DOI) information can improve quality of reconstructed images acquired from Positron Emission Tomography (PET), especially in high resolution and compact scanners dedicated for breast, brain, or small animal imaging applications. Additionally, clinical scanners with time of flight capability can also benefit from DOI information. One of the most promising methods of determining DOI in a crystal involves reading the signal from two ends of a scintillation crystal, and calculating the signal ratio between the two detectors. This method is known to deliver a better DOI resolution with rough crystals compared to highly polished crystals. However, what is still not well studied is how much of a tradeoff is involved between spatial, energy, temporal, and DOI resolutions as a function of the crystal surface treatment and geometry with the use of Silicon Photomultipliers (SiPM) as the photo detectors. This study investigates the effects of different crystal surface finishes and geometries on energy, timing and DOI resolutions at different crystal depths. The results show that for LYSO scintillators of 1.5×1.5×20 mm3 and 2×2×20 mm3 with their surfaces finished from 0.5 to 30 ?m roughness, almost the same energy and coincidence timing resolutions were maintained, around 15% and 2.4 ns, respectively across different crystal depths, while the DOI resolutions were steadily improved from worse than 5 mm to better than 2 mm. They demonstrate that crystal roughness, with proper surface preparing, does not have a significant effect on the energy and coincidence timing resolutions in the crystals examined, and there does not appear to be a tradeoff between improving DOI resolution and degrading other detector performances. These results will be valuable to guide the selection of crystal surface conditions for developing a DOI measurable PET detector with a full array of LYSO scintillators coupled to SiPM arrays.

  2. Development of a compact and fast response detector using an Yb:Lu2O3 scintillator for lifetime sensitive positron emission tomography

    NASA Astrophysics Data System (ADS)

    Taira, Y.; Kuroda, R.; Tanaka, M.; Oshima, N.; O'Rourke, B. E.; Suzuki, R.; Toyokawa, H.; Watanabe, K.; Yanagida, T.; Yagi, H.; Yanagitani, T.

    2014-05-01

    We propose a method for obtaining three-dimensional imaging measurements of the defect distribution inside industrial materials by measuring positron lifetimes, in addition to using the imaging technique of positron emission tomography. A compact and fast response detector that uses an Yb3+-doped Lu2O3 scintillator and a photomultiplier tube was developed and tested. Yb3+ charge transfer luminescence exhibits a fast response in the ultraviolet and visible regions. The first measurement of the positron lifetime for a bulk material using an Yb:Lu2O3 scintillator was carried out. The lifetime of positrons created inside an yttria-stabilized zirconia block via pair production produced by ultrashort photon pulses was successfully measured.

  3. Advances in scintillators for medical imaging applications

    NASA Astrophysics Data System (ADS)

    van Loef, Edgar V.; Shah, Kanai S.

    2014-09-01

    A review is presented of some recent work in the field of inorganic scintillator research for medical imaging applications, in particular scintillation detectors for Single-Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET).

  4. Scintillator Waveguide For Sensing Radiation

    DOEpatents

    Bliss, Mary (West Richland, WA); Craig, Richard A. (West Richland, WA); Reeder; Paul L. (Richland, WA)

    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.

  5. Development and calibration of a real-time airborne radioactivity monitor using direct gamma-ray spectrometry with two scintillation detectors.

    PubMed

    Casanovas, R; Morant, J J; Salvadó, M

    2014-07-01

    The implementation of in-situ gamma-ray spectrometry in an automatic real-time environmental radiation surveillance network can help to identify and characterize abnormal radioactivity increases quickly. For this reason, a Real-time Airborne Radioactivity Monitor using direct gamma-ray spectrometry with two scintillation detectors (RARM-D2) was developed. The two scintillation detectors in the RARM-D2 are strategically shielded with Pb to permit the separate measurement of the airborne isotopes with respect to the deposited isotopes.In this paper, we describe the main aspects of the development and calibration of the RARM-D2 when using NaI(Tl) or LaBr3(Ce) detectors. The calibration of the monitor was performed experimentally with the exception of the efficiency curve, which was set using Monte Carlo (MC) simulations with the EGS5 code system. Prior to setting the efficiency curve, the effect of the radioactive source term size on the efficiency calculations was studied for the gamma-rays from (137)Cs. Finally, to study the measurement capabilities of the RARM-D2, the minimum detectable activity concentrations for (131)I and (137)Cs were calculated for typical spectra at different integration times. PMID:24607535

  6. 3D Printing of Scintillating Materials

    E-print Network

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

    2014-01-01

    We demonstrate, for the first time, the applicability of 3D printing technique to the manufacture of scintillation detectors. We report 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 application.

  7. 3D Printing of Scintillating Materials

    E-print Network

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

    2014-06-15

    We demonstrate, for the first time, the applicability of 3D printing technique to the manufacture of scintillation detectors. We report 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 application.

  8. Effect of crystal shape, size and reflector type on operation characteristics of gamma-radiation detectors based on CsI(Tl) and CsI(Na) scintillators

    SciTech Connect

    Globus, M.E.; Grinyov, B.V.; Ratner, M.A. [Institute for Single Crystals, Kharkov (Ukraine)

    1996-12-31

    Operation characteristics of CsI(Tl) and CsI(Na) scintillation detectors, to a large degree connected with light collection in crystals, are calculated for various shapes, sizes and reflecting surface types. Allowance is made for the true light reflection indicatrix which is characterized by the effective mirror constituent of the reflected light, p. Its value

    , averaged over incidence angle, is used for the classification of reflecting surfaces. Operation characteristics (in particular, spectrometric ones) are found to be essentially dependent on

    . Tables of operation characteristics, given below, permit one to make inferential conclusions on an optimal combination of the shape, sizes an the reflecting surface version.

  9. Taheri-Saramad x-ray detector (TSXD): A novel high spatial resolution x-ray imager based on ZnO nano scintillator wires in polycarbonate membrane

    NASA Astrophysics Data System (ADS)

    Taheri, A.; Saramad, S.; Ghalenoei, S.; Setayeshi, S.

    2014-01-01

    A novel x-ray imager based on ZnO nanowires is designed and fabricated. The proposed architecture is based on scintillation properties of ZnO nanostructures in a polycarbonate track-etched membrane. Because of higher refractive index of ZnO nanowire compared to the membrane, the nanowire acts as an optical fiber that prevents the generated optical photons to spread inside the detector. This effect improves the spatial resolution of the imager. The detection quantum efficiency and spatial resolution of the fabricated imager are 11% and <6.8 ?m, respectively.

  10. Taheri-Saramad x-ray detector (TSXD): a novel high spatial resolution x-ray imager based on ZnO nano scintillator wires in polycarbonate membrane.

    PubMed

    Taheri, A; Saramad, S; Ghalenoei, S; Setayeshi, S

    2014-01-01

    A novel x-ray imager based on ZnO nanowires is designed and fabricated. The proposed architecture is based on scintillation properties of ZnO nanostructures in a polycarbonate track-etched membrane. Because of higher refractive index of ZnO nanowire compared to the membrane, the nanowire acts as an optical fiber that prevents the generated optical photons to spread inside the detector. This effect improves the spatial resolution of the imager. The detection quantum efficiency and spatial resolution of the fabricated imager are 11% and <6.8 ?m, respectively. PMID:24517750

  11. 950 keV X-Band Linac For Material Recognition Using Two-Fold Scintillator Detector As A Concept Of Dual-Energy X-Ray System

    SciTech Connect

    Lee, Kiwoo; Natsui, Takuya; Hirai, Shunsuke; Uesaka, Mitsuru [University of Tokyo, 2-22 Tokai-mura, Ibaraki-ken 319-1188 (Japan); Hashimoto, Eiko [Japan atomic energy agency (JAEA), 4-49 Muramatsu Tokai-mura, Ibaraki-ken (Japan)

    2011-06-01

    One of the advantages of applying X-band linear accelerator (Linac) is the compact size of the whole system. That shows us the possibility of on-site system such as the custom inspection system in an airport. As X-ray source, we have developed X-band Linac and achieved maximum X-ray energy 950 keV using the low power magnetron (250 kW) in 2 {mu}s pulse length. The whole size of the Linac system is 1x1x1 m{sup 3}. That is realized by introducing X-band system. In addition, we have designed two-fold scintillator detector in dual energy X-ray concept. Monte carlo N-particle transport (MCNP) code was used to make up sensor part of the design with two scintillators, CsI and CdWO4. The custom inspection system is composed of two equipments: 950 keV X-band Linac and two-fold scintillator and they are operated simulating real situation such as baggage check in an airport. We will show you the results of experiment which was performed with metal samples: iron and lead as targets in several conditions.

  12. Measurements of high energy neutrons penetrated through iron shields using the Self-TOF detector and an NE213 organic liquid scintillator

    NASA Astrophysics Data System (ADS)

    Sasaki, M.; Nakao, N.; Nunomiya, T.; Nakamura, T.; Fukumura, A.; Takada, M.

    2002-11-01

    Neutron energy spectra penetrated through iron shields were measured using the Self-TOF detector and an NE213 organic liquid scintillator which have been newly developed by our group at the Heavy-Ion Medical Accelerator in Chiba (HIMAC) of National Institute of Radiological Sciences (NIRS), Japan. Neutrons were generated by bombarding 400 MeV/nucleon C ion on a thick (stopping-length) copper target. The neutron spectra in the energy range from 20 to 800 MeV were obtained through the FORIST unfolding code with their response functions and compared with the MCNPX calculations combined with the LA150 cross section library. The neutron fluence measured by the NE213 detector was simulated by the track length estimator in the MCNPX, and evaluated the contribution of the room-scattered neutrons. The calculations are in fairly good agreement with the measurements. Neutron fluence attenuation lengths were obtained from the experimental results and the calculation.

  13. Monte Carlo simulation of prompt gamma-ray spectra from depleted uranium under D-T neutron irradiation and electron recoil spectra in a liquid scintillator detector

    E-print Network

    Qin, Jianguo; Liu, Rong; Zhu, Tonghua; Zhang, Xinwei; Ye, Bangjiao

    2015-01-01

    To overcome the problem of inefficient computing time and unreliable results in MCNP5 calculation, a two-step method is adopted to calculate the energy deposition of prompt gamma-rays in detectors for depleted uranium spherical shells under D-T neutrons irradiation. In the first step, the gamma-ray spectrum for energy below 7 MeV is calculated by MCNP5 code; secondly, the electron recoil spectrum in a BC501A liquid scintillator detector is simulated based on EGSnrc Monte Carlo Code with the gamma-ray spectrum from the first step as input. The comparison of calculated results with experimental ones shows that the simulations agree well with experiment in the energy region 0.4-3 MeV for the prompt gamma-ray spectrum and below 4 MeVee for the electron recoil spectrum. The reliability of the two-step method in this work is validated.

  14. Searching for Galactic Hidden Gas through interstellar scintillation: Results from a test with the NTT-SOFI detector

    E-print Network

    Habibi, F; Ansari, R; Rahvar, S

    2010-01-01

    Aims: Stars twinkle because their light propagates through the atmosphere. The same phenomenon is expected at longer time scale when the light of remote stars crosses an interstellar molecular cloud, but it has never been observed at optical wavelength. In a favorable case, the light of a background star can be subject to stochastic fluctuations of order of a few percent at a characteristic time scale of a few minutes. Our ultimate aim is to discover or exclude such scintillation effects, in order to estimate the contribution of molecular hydrogen to the Galactic baryonic hidden mass. This feasibility study is a pathfinder towards an observational strategy to search for scintillation, probing sensitivity of future surveys and estimating the background level. Methods: Scintillation induced by molecular gas in visible dark nebulae as well as by hypothetical halo clumpuscules of cool molecular hydrogen ($\\mathrm{H_2-He}$) has been searched for during two nights. We have taken long series of 10s infrared exposure...

  15. A direct method for evaluating the concentration of boric acid in a fuel pool using scintillation detectors for joint-multiplicity measurements

    NASA Astrophysics Data System (ADS)

    Chernikova, Dina; Axell, Kåre; Pázsit, Imre; Nordlund, Anders; Sarwar, Rashed

    2013-06-01

    The present investigations are aimed at the development of a direct passive non-intrusive method for determining the concentration of boric acid in a spent fuel pool using scintillation detectors with the purpose of correcting joint-multiplicity measurement results. The method utilizes a modified relation between two gamma lines with energy of 480 keV and 2.23 MeV, respectively. The gamma line at 480 keV belongs to the thermal neutron capture in boron. The 2.23 MeV gamma line characterizes the capture of thermal neutrons in hydrogen. Thus, the relation between them can reveal the concentration of the boron in the fuel pool. In order to test this method, first MCNPX and MCNP-PoliMi simulations were performed. Then, based on the results of Monte Carlo simulations, the method was verified by an experimental study with a 241Am-Be source and EJ-309 scintillation detectors. The concentration of boron in water varied from 1550 ppm to 4000 ppm. The results of these tests are provided in the paper and they show that the spectral ratio between these two lines can in principle be used to determine the boron content.

  16. Direct Deposition of Microcolumnar Scintillator on CMOS SSPM Array: Toward a Photon Counting Detector for X-Ray/Gamma Ray Imaging

    NASA Astrophysics Data System (ADS)

    Prekas, G.; Breen, M.; Sabet, H.; Bhandari, H.; Derderian, G.; Robertson, F.; Stapels, C. J.; Christian, J.; Cool, S.; Nagarkar, V. V.

    2011-12-01

    We are developing a modular, low-cost, photon-counting detector based on a scintillator coupled to a solid-state photodetector. A working prototype was successfully developed by depositing CsI:Tl directly onto a CMOS SSPM array designed by RMD and custom-fabricated by a commercial foundry. The device comprised a 6×6 array of 1.5×1.5 mm2 macro-pixels, each containing a 36×36 array of resistively coupled micro-pixels, that was subjected to vapor deposition of columnar CsI:Tl. Direct deposition eliminates the gap between the scintillator and SSPM and creates a better optical bond than does index-matching grease. This paper compares the performance of SSPMs with directly deposited CsI:Tl, in terms of signal-to-noise ratio and light spread, against devices using monolithic single crystals or pixelated single crystals coupled to the SSPM. Due to the reduction in light scattering and optical losses in the interface, the directly deposited CsI:Tl demonstrated significantly better position sensitivity, with at least a factor of 2 increase in SNR compared to a single crystal. These data indicate that a photodetector with substantially smaller macro-pixel dimensions than used here could be used to implement a low-energy X-ray/gamma-ray imaging and spectroscopy detector, particularly for applications where high resolution is of prime importance.

  17. Development of phosphor scintillator-based detectors for soft x-ray and vacuum ultraviolet spectroscopy of magnetically confined fusion plasmas

    NASA Astrophysics Data System (ADS)

    Soukhanovskii, V. A.; Regan, S. P.; May, M. J.; Finkenthal, M.; Moos, H. W.

    2003-10-01

    Specialized soft x-ray and vacuum ultraviolet (VUV) diagnostics used to monitor impurity emissions from fusion plasmas are often placed in a very challenging experimental environment. Detectors in these diagnostics must be simple; mechanically robust; immune to electromagnetic interference, energetic particles, and magnetic fields up to several tesla; ultra-high-vacuum compatible; and able to withstand bakeout temperatures up to 300 °C. The design and the photometric calibration of a detector consisting of a P45 phosphor (Y2O2S:Tb), two incoherent fiber-optic bundles coupled with a vacuum feedthrough fiber-optic faceplate, and a photomultiplier tube (PMT) are reported. We have successfully operated the detectors of this type in novel soft x-ray and VUV diagnostics on several fusion plasma facilities. Measurements of the visible photon throughput of the silica/silica incoherent fiber-optic bundle, and the light loss associated with the coupling of the two fibers with the faceplate are presented. In addition, improved absolute measurements of the conversion efficiency of the P45/PMT photodetector based upon the use of a PMT with a bialkali photocathode instead of a multialkali one are presented for the soft x-ray and VUV range of photon wavelengths. The conversion efficiency is defined as the ratio of the photoelectrons ejected from the photocathode of a visible detector, which are excited by the scintillated photons that are emitted from the phosphor in a solid angle of 2?, to the number of soft x-ray photons incident on the phosphor. Sensitive electronic gain measurements of the PMT using the visible scintillated light from the P45 phosphor are compared with the gain measurements supplied by the manufacturer of the PMT, which were performed with a tungsten filament lamp operated at 2856 K.

  18. Photofraction of a 5 cm x 2 cm BGO scintillator. [bismuth germanate crystal for use in cosmic gamma ray detector

    NASA Technical Reports Server (NTRS)

    Dunphy, P. P.; Forrest, D. J.

    1985-01-01

    The photofraction of a 5.1 cm x 2.0 cm bismuth germanate (BGO) scintillator was measured over a gamma-ray energy range of 0.2 to 6.1 MeV. Several methods, used to minimize the effect of room scattering on the measurement, are discussed. These include a gamma-gamma coincidence technique, a beta-gamma coincidence technique, and the use of sources calibrated with a standard 7.6 cm x 7.6 cm sodium iodide scintillator.

  19. Decay time and pulse shape discrimination of liquid scintillators based on novel solvents

    NASA Astrophysics Data System (ADS)

    Lombardi, Paolo; Ortica, Fausto; Ranucci, Gioacchino; Romani, Aldo

    2013-02-01

    Over the past few years the liquid scintillation technique employed for particle detection applications has undergone a significant technological breakthrough with the introduction of novel solvents tailored to address the concerns about toxicity, flammability and disposal problems associated with the scintillators of traditional formulation. The increasing popularity of the new solvents in the realization of experimental set-ups of various degrees of size and complexity implies the need of a thorough study and characterization of the features of the corresponding scintillation mixtures, with the aim to approach eventually a level of understanding similar to that, very accurate, achieved throughout many years of research for the scintillators realized with conventional solvents. In this general context, aim of this work is to illustrate the results of the fluorescence decay time and pulse shape discrimination measurements carried out on a set of scintillation mixtures realized using two of such novel solvents, i.e., linear alkylbenzene (LAB) and di-isopropylnaphthalene (DIN). The measurements have been performed either under particle or UV excitation of the scintillating solutions, which permitted to unravel the features both of the fast component and of the long tail forming the entire scintillation pulse. Moreover, the particle characterization via ? or ? excitation allows also predicting the ??? pulse shape discrimination capability of the mixtures, a property of paramount significance for applications focused on the increasingly important field of low background detectors.

  20. Evaluation of a setup for pNRA at LIBAF for applications in geosciences

    NASA Astrophysics Data System (ADS)

    Borysiuk, M.; Kristiansson, P.; Ros, L.; Abdel, N.; Elfman, M.; Nilsson, E. J. C.; Pallon, J.

    2014-08-01

    A new setup for photon tagged nuclear reaction analysis pNRA is being developed at Lund's ion beam analysis facility LIBAF. Particle induced gamma ray emission PIGE and nuclear reaction analysis NRA are two methods that have been extensively used for light isotope measurement in ion beam analysis IBA. There is an abundance of nuclear reactions between light elements and MeV protons, deuterons and alpha particles. This means that in principle all elements from lithium all the way up to chlorine can be analyzed using those techniques. Detection limits can be improved for some elements, if those two methods are fused together into pNRA. The new setup for pNRA will benefit from advances in detector technology that occurred during the last 20 years. A LaBr3 scintillator detector and an annular double sided silicon strip detector DSSSD are used in coincidence to detect a gamma and a charged particle respectively. Both detectors are connected to a VME based data acquisition system. Of primary interest in this work is the analysis of isotopic ratios of light elements in geological samples, which are usually thick with a complex matrix. This setup can be for instance used to measure isotopic fractionation of oxygen and boron. We will present the setup and discuss its capabilities.

  1. Searching for Galactic hidden gas through interstellar scintillation: results from a test with the NTT-SOFI detector

    NASA Astrophysics Data System (ADS)

    Habibi, F.; Moniez, M.; Ansari, R.; Rahvar, S.

    2011-01-01

    Aims: Stars twinkle because their light propagates through the atmosphere. The same phenomenon is expected at a longer time scale when the light of remote stars crosses an interstellar molecular cloud, but it has never been observed at optical wavelength. In a favorable case, the light of a background star can be subject to stochastic fluctuations on the order of a few percent at a characteristic time scale of a few minutes. Our ultimate aim is to discover or exclude these scintillation effects to estimate the contribution of molecular hydrogen to the Galactic baryonic hidden mass. This feasibility study is a pathfinder toward an observational strategy to search for scintillation, probing the sensitivity of future surveys and estimating the background level. Methods: We searched for scintillation induced by molecular gas in visible dark nebulae as well as by hypothetical halo clumpuscules of cool molecular hydrogen (H2-He) during two nights. We took long series of 10 s infrared exposures with the ESO-NTT telescope toward stellar populations located behind visible nebulae and toward the Small Magellanic Cloud (SMC). We therefore searched for stars exhibiting stochastic flux variations similar to what is expected from the scintillation effect. According to our simulations of the scintillation process, this search should allow one to detect (stochastic) transverse gradients of column density in cool Galactic molecular clouds of order of ~ 3 × 10-5 g/cm2/10 000 km. Results: We found one light-curve that is compatible with a strong scintillation effect through a turbulent structure characterized by a diffusion radius Rdiff < 100 km in the B68 nebula. Complementary observations are needed to clarify the status of this candidate, and no firm conclusion can be established from this single observation. We can also infer limits on the existence of turbulent dense cores (of number density n > 109 cm-3) within the dark nebulae. Because no candidate is found toward the SMC, we are also able to establish upper limits on the contribution of gas clumpuscules to the Galactic halo mass. Conclusions: The limits set by this test do not seriously constrain the known models, but we show that the short time-scale monitoring for a few 106 star × hour in the visible band with a >4 m telescope and a fast readout camera should allow one to quantify the contribution of turbulent molecular gas to the Galactic halo. The LSST (Large Synoptic Survey Telescope) is perfectly suited for this search. This work is based on observations made at the European Southern Observatory, La Silla, Chile.

  2. 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.

  3. Scintillator fiber optic long counter

    DOEpatents

    McCollum, Tom (Sterling, VA); Spector, Garry B. (Fairfax, VA)

    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.

  4. Signal and noise characteristics induced by unattenuated x rays from a scintillator in indirect-conversion CMOS photodiode array detectors

    E-print Network

    Cunningham, Ian

    -conversion CMOS photodiode array detectors Seung Man Yun1 , Chang Hwy Lim1 , Ho Kyung Kim1,* , Thorsten Graeve2 by the direct x-rays in an indirect-conversion CMOS photodiode array detector. In order to isolate the signal show the direct x-ray is very harmful to the detector performances, such noise power spectrum (NPS

  5. Extruded plastic scintillator for MINERvA

    SciTech Connect

    Pla-Dalmau, Anna; Bross, Alan D.; /Fermilab; 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.

  6. Integrated readout of organic scintillator and ZnS:Ag/6LiF for segmented antineutrino detectors.

    SciTech Connect

    Kiff, Scott D.; Reyna, David; Monahan, James; Bowden, Nathaniel S.

    2010-11-01

    Antineutrino detection using inverse beta decay conversion has demonstrated the capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which highly efficient capture and identification of neutrons is needed to measure the anticipated antineutrino event rates in an elevated background environment. In this submission, we report on initial characterization of a new scintillation-based segmented design that uses layers of ZnS:Ag/{sup 6}LiF and an integrated readout technique to capture and identify neutrons created in the inverse beta decay reaction. Laboratory studies with multiple organic scintillator and ZnS:Ag/{sup 6}LiF configurations reliably identify {sup 6}Li neutron captures in 60 cm-long segments using pulse shape discrimination.

  7. Integrated readout of organic scintillator and ZnS:Ag/6LiF for segmented antineutrino detectors.

    SciTech Connect

    Kiff, Scott D.; Reyna, David; Monahan, James (Drexel University, Philadelphia, PA); Bowden, Nathaniel S. (Lawrence Livermore National Laboratory, Livermore, CA)

    2010-10-01

    Antineutrino detection using inverse beta decay conversion has demonstrated the capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which highly efficient capture and identification of neutrons is needed to measure the anticipated antineutrino event rates in an elevated background environment. In this submission, we report on initial characterization of a new scintillation-based segmented design that uses layers of ZnS:Ag/{sup 6}LiF and an integrated readout technique to capture and identify neutrons created in the inverse beta decay reaction. Laboratory studies with multiple organic scintillator and ZnS:Ag/{sup 6}LiF configurations reliably identify {sup 6}Li neutron captures in 60 cm-long segments using pulse shape discrimination.

  8. Scintillation Mathematics

    E-print Network

    Baxter, Paul D.

    ' & $ % The Extraction of Scintillation Statistics from Italsat 50 GHz Beacon Data using Wavelets P wavelet method of wet scintillation extraction, assessing the impact on scintillation statistics to the index i as the dilation level and the index j as the translation index. COST 280 MCM4 10 #12

  9. Use of digirad 2020tc Imager, a multi-crystal scintillation camera with solid-state detectors in one case for the imaging of autografts of parathyroid glands.

    PubMed

    Fukumitsu, N; Tsuchida, D; Ogi, S; Uchiyama, M; Mori, Y; Ooshita, T; Narrita, H; Yamamoto, H; Takeyama, H

    2001-12-01

    99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI) scintigraphy with Digirad 2020tc ImagerTM (2020tc), which was a multi-crystal scintillation camera with solid-state detectors was performed for patients with secondary hyperparathyroidism having autografts of parathyroid glands in the right arm. With the 2020tc camera, three abnormal accumulations were found in the right arm. The images obtained with this camera were superior in resolution to those obtained with a conventional NaI crystal gamma camera (ZLC7500, Siemens, Germany). The next day, resection of autografts of parathyroid glands was done. Four hyperplastic parathyroid glands were resected and all were hyperplastic in pathological findings. PMID:11831402

  10. 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.

  11. Scintillator materials containing lanthanum fluorides

    DOEpatents

    Moses, William W. (Berkeley, CA)

    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.

  12. Timing characteristics of scintillator bars

    NASA Astrophysics Data System (ADS)

    Denisov, S.; Dzierba, A.; Heinz, R.; Klimenko, A.; Samoylenko, V.; Scott, E.; Shchukin, A.; Smith, P.; Steffen, C.; Teige, S.

    2002-02-01

    The proposed Hall D detector at Jefferson Lab will have a time-of-flight detector composed of long and narrow scintillator bars. We have evaluated the time resolution of two bar prototypes in particle beams at the Institute for High Energy Physics in Protvino, Russia. The bars are 2.0 m long and have square cross-sections of size 2.5 and 5.0 cm2. In this paper, we present results on how the time resolution of each of these bars depends on the entry position of the beam into the scintillator, on the material used for scintillator wrapping and on the phototube used for the readout.

  13. Scintillators with Silicon Photomultiplier Readout for Timing Measurements in Hadronic Showers

    E-print Network

    Soldner, Christian

    2011-01-01

    The advent of silicon photomultipliers has enabled big advances in high energy physics instrumentation, for example by allowing the construction of extremely granular hadronic calorimeters with photon sensors integrated into small scintillator tiles. Direct coupling of the SiPM to the plastic scintillator, without use of wavelength shifting fibers, provides a fast detector response, making such devices well suited for precise timing measurements. We have constructed a setup consisting of 15 such scintillator tiles read out with fast digitizers with deep buffers to measure the time structure of signals in hadronic calorimeters. Specialized data reconstruction algorithms that allow the determination of the arrival time of individual photons by a detailed analysis of the recorded waveforms and that provide automatic calibration of the gain of the photon sensor, have been developed. We will discuss the experimental apparatus and the data analysis. In addition, we will report on first results obtained in a hadroni...

  14. Neutrino factory near detector

    NASA Astrophysics Data System (ADS)

    Bogomilov, M.; Karadzhov, Y.; Matev, R.; Tsenov, R.; Laing, A.; Soler, F. J. P.

    2013-08-01

    The neutrino factory is a facility for future precision studies of neutrino oscillations. A so-called near detector is essential for reaching the required precision for a neutrino oscillation analysis. The main task of the near detector is to measure the flux of the neutrino beam. Such a high intensity neutrino source like a neutrino factory provides also the opportunity for precision studies of various neutrino interaction processes in the near detector. We discuss the design concepts of such a detector. Results of simulations of a high resolution scintillating fiber tracker show that such a detector is capable of determining the neutrino flux normalization with an uncertainty of less than 1% by measuring pure leptonic interactions. Reconstruction of the neutrino energy in each event and a flux estimation based on the shapes of the neutrino energy spectra are discussed. A full setup of the near detector, consisting of a high granularity vertex detector, high resolution tracker, and muon catcher is also presented. Finally, a method to extrapolate the measured near detector flux to the far detector is shown, demonstrating that it is able to extract the correct values of ?13 and the CP violation phase ? without any significant bias and with high accuracy.

  15. [Evaluation of efficiency of a multi-crystal scintillation camera Digirad 2020tc Imager using a solid-state detectors].

    PubMed

    Narita, H; Kawaida, Y; Ooshita, T; Itoh, T; Tsuchida, D; Fukumitsu, N; Mori, Y; Makino, M

    2001-07-01

    Digirad 2020tc Imager is the movable scintillation camera, consisting of combining multi-crystal scintillators (CsI(Tl)) and photo-diodes. Total numbers of element are 4096, which are further divided into 16 x 16 modules. Each module contains 4 x 4 elements. We have examined Digirad 2020tc according to NEMA (National Electrical Manufactures Association), and the following results are obtained; the maximum count rate; 221 kcps, total system uniformity; 1.3% (integral uniformity), 0.9% (differential uniformity), system spatial resolution; 6.97 +/- 0.72 mm (the LEHR collimator to 99mTc source at 10 cm), intrinsic energy resolution; 12.8%, total system sensitivity; 3270.8 cpm/MBq (with LEHR collimator using 99mTc source at 10 cm). Further more, we determined the contrast of an imaging using the pin-hole (100 microns phi) 99mTc source in order to know the signal per noise (S/N) ratio among the pixels (S/N; 93.4 +/- 46.2 (first pixels)). Although the physical dimension of the camera has a smaller field of view, comparing with the standard camera, Digirad 2020tc has the equivalent characteristics as well as that of the standard camera and its field view is enough to measure the adult lung perfusion using a diverging collimator. We will further examine Digirad 2020tc with its movable portability and expect applications in nuclear medicine. PMID:11530383

  16. High Efficiency, Low Cost Scintillators for PET

    SciTech Connect

    Kanai Shah

    2007-03-06

    Inorganic scintillation detectors coupled to PMTs are an important element of medical imaging applications such as positron emission tomography (PET). Performance as well as cost of these systems is limited by the properties of the scintillation detectors available at present. The Phase I project was aimed at demonstrating the feasibility of producing high performance scintillators using a low cost fabrication approach. Samples of these scintillators were produced and their performance was evaluated. Overall, the Phase I effort was very successful. The Phase II project will be aimed at advancing the new scintillation technology for PET. Large samples of the new scintillators will be produced and their performance will be evaluated. PET modules based on the new scintillators will also be built and characterized.

  17. A new water-equivalent 2D plastic scintillation detectors array for the dosimetry of megavoltage energy photon beams in radiation therapy

    SciTech Connect

    Guillot, Mathieu; Beaulieu, Luc; Archambault, Louis; Beddar, Sam; Gingras, Luc [Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec, Quebec G1R 2J6 (Canada); Department of Radiation Physics, Unit 94, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec, Quebec G1R 2J6 (Canada)

    2011-12-15

    Purpose: The objective of this work is to present a new 2D plastic scintillation detectors array (2D-PSDA) designed for the dosimetry of megavoltage (MV) energy photon beams in radiation therapy and to characterize its basic performance. Methods: We developed a 2D detector array consisting of 781 plastic scintillation detectors (PSDs) inserted into a plane of a water-equivalent phantom. The PSDs were distributed on a 26 x 26 cm{sup 2} grid, with an interdetector spacing of 10 mm, except for two perpendicular lines centered on the detection plane, where the spacing was 5 mm. Each PSD was made of a 1 mm diameter by 3 mm long cylindrical polystyrene scintillating fiber coupled to a clear nonscintillating plastic optical fiber. All of the light signals emitted by the PSDs were read simultaneously with an optical system at a rate of one measurement per second. We characterized the performance of the optical system, the angular dependency of the device, and the perturbation of dose distributions caused by the hundreds of PSDs inserted into the phantom. We also evaluated the capacity of the system to monitor complex multileaf collimator (MLC) sequences such as those encountered in step-and-shoot intensity modulated radiation therapy (IMRT) plans. We compared our results with calculations performed by a treatment planning system and with measurements taken with a 2D ionization chamber array and with a radiochromic film. Results: The detector array that we developed allowed us to measure doses with an average precision of better than 1% for cumulated doses equal to or greater than 6.3 cGy. Our results showed that the dose distributions produced by the 6-MV photon beam are not perturbed (within {+-}1.1%) by the presence of the hundreds of PSDs located into the phantom. The results also showed that the variations in the beam incidences have little effect on the dose response of the device. For all incidences tested, the passing rates of the gamma tests between the 2D-PSDA and the treatment planning system were higher than 97.5% when the standard clinical tolerances of 3% or 3 mm were used. Excellent agreement was obtained between the doses measured and calculated when we used the 2D-PSDA for monitoring a MLC sequence from a step-and-shoot IMRT plan. Conclusions: We demonstrated the feasibility of using a large number of PSDs in a new 2D-PSDA for the dosimetry of MV energy photon beams in radiation therapy. The excellent precision, accuracy, and low angular dependence of the device indicate that such a prototype could potentially be used as a high-accuracy quality assurance tool for IMRT and arc therapy patient plan verification. The homogeneity and water-equivalence of the prototype we built suggest that this technology could be extended to multiple detection planes by arranging the fibers into more complex orientations, opening the possibility for 3D dosimetry with PSDs.

  18. Optical fiber readout of scintillator arrays using a multi-channel PMT: a high resolution PET detector for animal imaging

    Microsoft Academic Search

    Simon R. Cherry; Yiping Shao; Stefan Siegel; Robert W. Silverman; Erkan Mumcuoglu; Ken Meadors; Michael E. Phelps

    1996-01-01

    The authors report the results from a new high resolution gamma ray imaging detector designed for use in a positron emission tomography (PET) system dedicated to small animal imaging. The detectors consist of an 8×8 array of 2×2×10 mm bismuth germanate (BGO) crystals coupled by 2 mm diameter double clad optical fibers to a 64 pixel multi-channel photomultiplier tube (MC-PMT).

  19. 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.

  20. 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.

  1. Scintillator material

    DOEpatents

    Anderson, David F. (Batavia, IL); Kross, Brian J. (Aurora, IL)

    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.

  2. Scintillator material

    DOEpatents

    Anderson, David F. (Batavia, IL); Kross, Brian J. (Aurora, IL)

    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.

  3. A microplate solid scintillation counter as a radioactivity detector for high performance liquid chromatography in drug metabolism: validation and applications.

    PubMed

    Bruin, Gerard J; Waldmeier, Felix; Boernsen, K Olaf; Pfaar, Ulrike; Gross, Gerhard; Zollinger, Markus

    2006-11-10

    Sensitive radioactivity detection following high performance liquid chromatography (HPLC) separation remains a challenge in many drug metabolism studies with radiolabeled compounds. In this work, solid scintillation counting (SSC) after fraction collection into 96-well plates was evaluated as an off-line radioactivity detection method, in comparison with conventional liquid scintillation counting (LSC). The impact of counting time and biological matrix on the quantification of radiolabeled metabolites and parent drug in samples from animal and human absorption, distribution, metabolism and excretion (ADME) studies was investigated. Three different approaches were used to test whether reliable quantification by off-line SSC detection, which requires an approximately constant counting yield during the entire chromatographic run, can be realized: (i) the measurement of radioactivity-spiked biological blank samples without HPLC separation as an extreme case of biological background, (ii) the measurement of radioactivity-spiked HPLC fractions of biological blank samples and (iii) the comparison of radiochromatograms obtained by off-line SSC and LSC of real samples from ADME studies with radiolabeled compounds. Situations in which variations in SSC yield during an HPLC run are likely to lead to significant errors in quantitation were identified and are discussed. However, examples from a number of animal or human ADME studies showed that in the majority of cases off-line SSC provides very similar quantitative data, compared with the reference method of off-line LSC radioactivity detection. Approaches for validation of the off-line SSC approach in critical cases are discussed. The main advantages of off-line SSC, compared with off-line LSC, are lower detection limits and a substantially higher throughput. Several applications of off-line SSC detection in ADME studies are shown. PMID:16970958

  4. Indirect flat-panel detector with avalanche gain: Fundamental feasibility investigation for SHARP-AMFPI (scintillator HARP active matrix flat panel imager)

    SciTech Connect

    Zhao Wei; Li Dan; Reznik, Alla; Lui, B.J.M.; Hunt, D.C.; Rowlands, J.A.; Ohkawa, Yuji; Tanioka, Kenkichi [Department of Radiology, State University of New York at Stony Brook, L-4, 120 Health Sciences Center Stony Brook, New York 11793-8460 (United States); Imaging Research, Sunnybrook and Women's Health Sciences Center, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5 (Canada); Advanced Imaging Devices Research Division, Science and Technical Research Laboratories, Japan Broadcasting Corporation, 1-10-11 Kinuta, Setagaya-ku, Tokyo 157-8510 (Japan)

    2005-09-15

    An indirect flat-panel imager (FPI) with avalanche gain is being investigated for low-dose x-ray imaging. It is made by optically coupling a structured x-ray scintillator CsI(Tl) to an amorphous selenium (a-Se) avalanche photoconductor called HARP (high-gain avalanche rushing photoconductor). The final electronic image is read out using an active matrix array of thin film transistors (TFT). We call the proposed detector SHARP-AMFPI (scintillator HARP active matrix flat panel imager). The advantage of the SHARP-AMFPI is its programmable gain, which can be turned on during low dose fluoroscopy to overcome electronic noise, and turned off during high dose radiography to avoid pixel saturation. The purpose of this paper is to investigate the important design considerations for SHARP-AMFPI such as avalanche gain, which depends on both the thickness d{sub Se} and the applied electric field E{sub Se} of the HARP layer. To determine the optimal design parameter and operational conditions for HARP, we measured the E{sub Se} dependence of both avalanche gain and optical quantum efficiency of an 8 {mu}m HARP layer. The results were used in a physical model of HARP as well as a linear cascaded model of the FPI to determine the following x-ray imaging properties in both the avalanche and nonavalanche modes as a function of E{sub Se}: (1) total gain (which is the product of avalanche gain and optical quantum efficiency); (2) linearity; (3) dynamic range; (4) gain nonuniformity resulting from thickness nonuniformity; and (5) effects of direct x-ray interaction in HARP. Our results showed that a HARP layer thickness of 8 {mu}m can provide adequate avalanche gain and sufficient dynamic range for x-ray imaging applications to permit quantum limited operation over the range of exposures needed for radiography and fluoroscopy.

  5. A technique for verifying the input response function of neutron time-of-flight scintillation detectors using cosmic rays

    SciTech Connect

    Bonura, M. A.; Cooper, G. W.; Nelson, A. J.; Styron, J. D. [Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Ruiz, C. L., E-mail: clruiz@sandia.gov; Fehl, D. L.; Chandler, G.; Hahn, K. D.; Torres, J. A. [Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111 (United States)

    2014-11-15

    An accurate interpretation of DD or DT fusion neutron time-of-flight (nTOF) signals from current mode detectors employed at the Z-facility at Sandia National Laboratories requires that the instrument response functions (IRF’s) be deconvolved from the measured nTOF signals. A calibration facility that produces detectable sub-ns radiation pulses is typically used to measure the IRF of such detectors. This work, however, reports on a simple method that utilizes cosmic radiation to measure the IRF of nTOF detectors, operated in pulse-counting mode. The characterizing metrics reported here are the throughput delay and full-width-at-half-maximum. This simple approach yields consistent IRF results with the same detectors calibrated in 2007 at a LINAC bremsstrahlung accelerator (Idaho State University). In particular, the IRF metrics from these two approaches and their dependence on the photomultipliers bias agree to within a few per cent. This information may thus be used to verify if the IRF for a given nTOF detector employed at Z has changed since its original current-mode calibration and warrants re-measurement.

  6. Method of making a scintillator waveguide

    SciTech Connect

    Bliss, Mary (West Richland, WA); Craig, Richard A. (West Richland, WA); Reeder, Paul L. (Richland, WA)

    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.

  7. A compact and high sensitivity positron detector using dual-layer thin GSO scintillators for a small animal PET blood sampling system

    NASA Astrophysics Data System (ADS)

    Yamamoto, Seiichi; Imaizumi, Masao; Shimosegawa, Eku; Kanai, Yasukazu; Sakamoto, Yusuke; Minato, Kotaro; Shimizu, Keiji; Senda, Michio; Hatazawa, Jun

    2010-07-01

    For quantitative measurements of small animals such as mice or rats, a compact and high sensitivity continuous blood sampling detector is required because their blood sampling volume is limited. For this purpose we have developed and tested a new positron detector. The positron detector uses a pair of dual-layer thin gadolinium orthosilicate (GSO) scintillators with different decay times. The front layer detects the positron and the background gamma photons, and the back layer detects the background gamma photons. By subtracting the count rate of the latter from that of the former, the count rate of the positrons can be estimated. The GSO for the front layer has a Ce concentration of 1.5 mol% (decay time of 35 ns), and that for the back layer has a Ce concentration of 0.5 mol% (decay time of 60 ns). By using the pulse shape analysis, the count rate of these two GSOs can be discriminated. The thickness is 0.5 mm, which is thick enough to detect positrons while minimizing the detection of the background gamma photons. These two types of thin GSOs were optically coupled to each other and connected to a metal photomultiplier tube (PMT) through triangular light guides. The signal from the PMT was digitized by 100 MHz free-running A-D converters in the data acquisition system and digitally integrated at two different integration times for the pulse shape analysis. We obtained good separation of the pulse shape distributions of these two GSOs. The energy threshold level was decreased to 80 keV, increasing the sensitivity of the detector. The sensitivity of a small diameter plastic tube was 8.6% and 24% for the F-18 and C-11 positrons, respectively. The count rate performance was linear up to ~50 kcps. The background counts from the gamma photons could be precisely corrected. The time-activity curve (TAC) of the rat artery blood was successfully obtained and showed a good correlation with that measured using a well counter. With these results, we confirmed that the developed blood sampling detector is promising for quantitative measurement for an animal positron emission tomography system.

  8. A compact and high sensitivity positron detector using dual-layer thin GSO scintillators for a small animal PET blood sampling system.

    PubMed

    Yamamoto, Seiichi; Imaizumi, Masao; Shimosegawa, Eku; Kanai, Yasukazu; Sakamoto, Yusuke; Minato, Kotaro; Shimizu, Keiji; Senda, Michio; Hatazawa, Jun

    2010-07-01

    For quantitative measurements of small animals such as mice or rats, a compact and high sensitivity continuous blood sampling detector is required because their blood sampling volume is limited. For this purpose we have developed and tested a new positron detector. The positron detector uses a pair of dual-layer thin gadolinium orthosilicate (GSO) scintillators with different decay times. The front layer detects the positron and the background gamma photons, and the back layer detects the background gamma photons. By subtracting the count rate of the latter from that of the former, the count rate of the positrons can be estimated. The GSO for the front layer has a Ce concentration of 1.5 mol% (decay time of 35 ns), and that for the back layer has a Ce concentration of 0.5 mol% (decay time of 60 ns). By using the pulse shape analysis, the count rate of these two GSOs can be discriminated. The thickness is 0.5 mm, which is thick enough to detect positrons while minimizing the detection of the background gamma photons. These two types of thin GSOs were optically coupled to each other and connected to a metal photomultiplier tube (PMT) through triangular light guides. The signal from the PMT was digitized by 100 MHz free-running A-D converters in the data acquisition system and digitally integrated at two different integration times for the pulse shape analysis. We obtained good separation of the pulse shape distributions of these two GSOs. The energy threshold level was decreased to 80 keV, increasing the sensitivity of the detector. The sensitivity of a small diameter plastic tube was 8.6% and 24% for the F-18 and C-11 positrons, respectively. The count rate performance was linear up to approximately 50 kcps. The background counts from the gamma photons could be precisely corrected. The time-activity curve (TAC) of the rat artery blood was successfully obtained and showed a good correlation with that measured using a well counter. With these results, we confirmed that the developed blood sampling detector is promising for quantitative measurement for an animal positron emission tomography system. PMID:20551500

  9. Scintillator identification and performance characteristics of LSO and GSO PSPMT detector modules combined through common X and Y resistive dividers

    Microsoft Academic Search

    J. Seidel; J. J. Vaquero; F. Barbosa; I. J. Lee; C. Cuevas; M. V. Green

    2000-01-01

    Combining signal channels from detector arrays can reduce complexity and minimize cost but, potentially, at the expense of other performance parameters. The authors evaluated a method that reduces the number of signals by combining the anode outputs of three position-sensitive photomultiplier tubes (PSPMTs) through a common X resistive charge divider and three individual Y resistive charge dividers. Field flood images

  10. 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.; /Northern Illinois U.; 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.

  11. Nuclear radiation detectors

    Microsoft Academic Search

    Luiz Alexandre Schuch; Daniel Jean Roger Nordemann

    1990-01-01

    Detectors of nuclear radiation, such as gaseous detectors, scintillators, and semiconductors, are presented through their general properties and with their operating systems. The semiconductor detectors are studied with more details.

  12. Scintillating double beta decay bolometers

    E-print Network

    S. Pirro; J. W. Beeman; S. Capelli; M. Pavan; E. Previtali; P. Gorla

    2005-10-27

    We present the results obtained in the development of scintillating Double Beta Decay bolometers. Several Mo and Cd based crystals were tested with the bolometric technique. The scintillation light was measured through a second independent bolometer. A 140 g CdWO_4 crystal was run in a 417 h live time measurement. Thanks to the scintillation light, the alpha background is easily discriminated resulting in zero counts above the 2615 keV gamma line of Thallium 208. These results, combined with an extremely easy light detector operation, represent the first tangible proof demonstrating the feasibility of this kind of technique.

  13. Liquid scintillator production for the NOvA experiment

    E-print Network

    S. Mufson; B. Baugh; C. Bower; T. E. Coan; J. Cooper; L. Corwin; J. A. Karty; P. Mason; M. D. Messier; A. Pla-Dalmau; M. Proudfoot

    2015-06-30

    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.

  14. Three-dimensional array of scintillation crystals with proper reflector arrangement for a depth of interaction detector

    Microsoft Academic Search

    Narimichi Orita; Hideo Murayama; Hideyuki Kawai; Naoko Inadama; Tomoaki Tsuda

    2005-01-01

    A new method to acquire four-layer depth of interaction (DOI) information is proposed for the next generation positron emission tomography scanner (jPET-D4) that realizes high resolution and high sensitivity. The detector module of the jPET-D4 is a 16×16×4 Gd2SiO5: Ce (GSO) multicrystal array coupled with a 256 ch flat panel position sensitive photomultiplier tube (256 ch FP-PMT) having large opening

  15. An evaluation of the Y2O3:Eu3+ scintillator for application in medical x-ray detectors and image receptors.

    PubMed

    Cavouras, D; Kandarakis, I; Panayiotakis, G S; Evangelou, E K; Nomicos, C D

    1996-12-01

    The suitability off a Y2O3:Eu3+ scintillator for use in radiation detectors and medical image receptors was studied. Y2O3:Eu3+ was used in the form of laboratory prepared screens of different coating thicknesses. The x-ray luminescence efficiency of the screens was measured for tube voltages between 50-200 kVp and in both transmission and reflection modes of observation. The intrinsic x ray to light conversation efficiency (nc) and other parameters of the Y2O3:Eu3+ phosphor material related to optical scattering, absorption, and reflection were determined. These were used in the calculation of the image transfer characteristics, MTF and zero frequency DQE, for various screen coating thicknesses and x-ray tube voltages. The light emission spectrum of Y2O3:Eu3+ was measured (narrow band peak at 613 nm) and its spectral compatibility to the spectral sensitivity of several commonly employed optical photon detectors was determined. The x-ray luminescence efficiency varied with x-ray tube voltage, attaining maximum value at about 80 kVp for all screen thicknesses. It also varied with coating thickness reaching 25 microW m(-2)/mR s(-1) and 18 microW m(-2)/mR s(-1) at 175 mg/cm2 for reflection and transmission modes, respectively. The intrinsic x ray to light conversion efficiency and the image transfer characteristics were found to be comparable to several commercially used phosphors: nc = 0.095, MTF0.05 ranged between 10 and 25 line pairs per mm and peal values of DQE(0) varied between 0.33 and 0.14 in the coating thickness and kVp ranges useful for x-ray imaging. Spectral compatibility to some red sensitive optical photon detectors was excellent (0.9 or better). Results indicated that Y2O3:Eu3+ is a medium to high overall performance material that could be used in medical x-ray detectors and image receptors. PMID:8994161

  16. Multilayer passive shielding of scintillation detectors based on BGO, NaI(Tl), and stilbene crystals operating in intense neutron fields with an energy of 14.1 MeV

    NASA Astrophysics Data System (ADS)

    Bystritsky, V. M.; Valkovic, V.; Grozdanov, D. N.; Zontikov, A. O.; Ivanov, I. Zh.; Kopatch, Yu. N.; Krylov, A. R.; Rogov, Yu. N.; Ruskov, I. N.; Sapozhnikov, M. G.; Skoy, V. R.; Shvetsov, V. N.

    2015-03-01

    We discuss the issues related to choosing the optimum type of passive shielding of scintillation detectors based on BGO, NaI(Tl), and stilbene crystals from the direct penetration of neutron radiation with an energy of 14.1 MeV that was emitted isotropically into a solid angle of 4?. A series of experimental measurements of the count-rate suppression factor that may be obtained for the indicated detectors through the use of various shielding filters comprising iron, lead, and borated polyethylene layers with a total thickness not exceeding 50 cm are conducted.

  17. Development of a high sensitive automatic setup for screening of microcystins in surface waters by employing a LED-based photometric detector

    Microsoft Academic Search

    Gláucia P. Vieira; Sheila R. W. Perdigão; Marli F. Fiore; Boaventura F. Reis

    In this manuscript, an automatic setup for screening of microcystins in surface waters by employing photometric detection is described. Microcystins are toxins delivered by cyanobacteria within an aquatic environment, which have been considered strongly poisonous for humans. For that reason, the World Health Organization (WHO) has proposed a provisional guideline value for drinking water of 1?gL?1. In this work, we

  18. Segmented crystalline scintillators: empirical and theoretical investigation of a high quantum efficiency EPID based on an initial engineering prototype CsI(TI) detector.

    PubMed

    Sawant, Amit; Antonuk, Larry E; El-Mohri, Youcef; Zhao, Qihua; Wang, Yi; Li, Yixin; Du, Hong; Perna, Louis

    2006-04-01

    Modern-day radiotherapy relies on highly sophisticated forms of image guidance in order to implement increasingly conformal treatment plans and achieve precise dose delivery. One of the most important goals of such image guidance is to delineate the clinical target volume from surrounding normal tissue during patient setup and dose delivery, thereby avoiding dependence on surrogates such as bony landmarks. In order to achieve this goal, it is necessary to integrate highly efficient imaging technology, capable of resolving soft-tissue contrast at very low doses, within the treatment setup. In this paper we report on the development of one such modality, which comprises a nonoptimized, prototype electronic portal imaging device (EPID) based on a 40 mm thick, segmented crystalline CsI(Tl) detector incorporated into an indirect-detection active matrix flat panel imager (AMFPI). The segmented detector consists of a matrix of 160 x 160 optically isolated, crystalline CsI(Tl) elements spaced at 1016 microm pitch. The detector was coupled to an indirect detection-based active matrix array having a pixel pitch of 508 microm, with each detector element registered to 2 x 2 array pixels. The performance of the prototype imager was evaluated under very low-dose radiotherapy conditions and compared to that of a conventional megavoltage AMFPI based on a Lanex Fast-B phosphor screen. Detailed quantitative measurements were performed in order to determine the x-ray sensitivity, modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE). In addition, images of a contrast-detail phantom and an anthropomorphic head phantom were also acquired. The prototype imager exhibited approximately 22 times higher zero-frequency DQE (approximately 22%) compared to that of the conventional AMFPI (approximately 1%). The measured zero-frequency DQE was found to be lower than theoretical upper limits (approximately 27%) calculated from Monte Carlo simulations, which were based solely on the x-ray energy absorbed in the detector-indicating the presence of optical Swank noise. Moreover, due to the nonoptimized nature of this prototype, the spatial resolution was observed to be significantly lower than theoretical expectations. Nevertheless, due to its high quantum efficiency (approximately 55%), the prototype imager exhibited significantly higher DQE than that of the conventional AMFPI across all spatial frequencies. In addition, the frequency-dependent DQE was observed to be relatively invariant with respect to the amount of incident radiation, indicating x-ray quantum limited behavior. Images of the contrast-detail phantom and the head phantom obtained using the prototype system exhibit good visualization of relatively large, low-contrast features, and appear significantly less noisy compared to similar images from a conventional AMFPI. Finally, Monte Carlo-based theoretical calculations indicate that, with proper optimization, further, significant improvements in the DQE performance of such imagers could be achieved. It is strongly anticipated that the realization of optimized versions of such very high-DQE EPIDs would enable megavoltage projection imaging at very low doses, and tomographic imaging from a "beam's eye view" at clinically acceptable doses. PMID:16696482

  19. 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. [Departement de Physique, Universite Laval, Quebec (Canada)

    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 PSDs, the PTW 60012 silicon diode, and the Gafchromics EBT2 agreed within 2% and 0.2 mm (gamma evaluation) for the measured dose profiles except in the tail of the 60-mm cone. Conclusions: Silicon diodes can be used to accurately measure small-field dose profiles but not to measure total scatter factors, whereas PSDs can be used to accurately measure both. The authors' measurements show that the use of a 1.0-mm PSD resulted in a negligible volume-averaging effect (under-response of Almost-Equal-To 1%) down to a field size of 5 mm. Therefore, PSDs are strong candidates to become reference radiosurgery detectors for beam characterization and quality assurance measurements.

  20. AMoRE: Collaboration for searches for the neutrinoless double-beta decay of the isotope of {sup 100}Mo with the aid of {sup 40}Ca{sup 100}MoO{sub 4} as a cryogenic scintillation detector

    SciTech Connect

    Khanbekov, N. D., E-mail: xanbekov@gmail.com [Institute of Theoretical and Experimental Physics (Russian Federation)

    2013-09-15

    The AMoRE (Advanced Mo based Rare process Experiment) Collaboration is planning to employ {sup 40}Ca{sup 100}MoO{sub 4} single crystals as a cryogenic Scintillation detector for studying the neutrinoless double-beta decay of the isotope {sup 100}Mo. A simultaneous readout of phonon and scintillation signals is performed in order to suppress the intrinsic background. The planned sensitivity of the experiment that would employ 100 kg of {sup 40}Ca{sup 100}MoO{sub 4} over five years of data accumulation would be T{sub 1/2}{sup 0{nu}} = 3 Multiplication-Sign 10{sup 26} yr, which corresponds to values of the effective Majorana neutrino mass in the range of Left-Pointing-Angle-Bracket m{sub {nu}} Right-Pointing-Angle-Bracket {approx} 0.02-0.06 eV.

  1. The NA49 large acceptance hadron detector

    E-print Network

    Afanasiev, S V; Appelshäuser, H; Bächler, J; Barna, D; Barnby, L S; Bartke, Jerzy; Barton, R A; Betev, L; Bialkowska, H; Bieser, F; Billmeier, A; Blyth, C O; Böck, R K; Bormann, C; Bracinik, J; Brady, F P; Brockmann, R; Brun, R; Buncic, P; Caines, H L; Cebra, D; Cooper, G E; Cramer, J G; Csató, P; Cyprian, M; Dunn, J; Eckardt, V; Eckhardt, F; Empl, T; Eschke, J; Ferguson, M I; Fessler, H; Fischer, H G; Flierl, D; Fodor, Z; Frankenfeld, Ulrich; Foka, P Y; Freund, P; Friese, V; Ftácnik, J; Fuchs, M; Gabler, F; Gál, J; Ganz, R E; Gazdzicki, M; Gladysz-Dziadus, E; Grebieszkow, J; Günther, J; Harris, J W; Hegyi, S; Henkel, T; Hill, L A; Hlinka, V; Huang, I; Hümmler, H; Igo, G; Irmscher, D; Ivanov, M; Janik, R; Jacobs, P; Jones, P G; Kadija, K; Kolesnikov, V I; Kowalski, M; Lasiuk, B; Lévai, Peter; Liebicher, K; Lynen, U; Malakhov, A I; Margetis, S; Markert, C; Marks, C; Mayes, B W; Melkumov, G L; Mock, A; Molnár, J; Nelson, J M; Oldenburg, M; Odyniec, Grazyna Janina; Pálla, G; Panagiotou, A D; Pestov, Yu N; Petridis, A; Pikna, M; Pimpl, W; Pinsky, L; Piper, A; Porter, R J; Poskanzer, A M; Poziombka, S; Prindle, D J; Pühlhofer, F; Rauch, W; Reid, J G; Renfordt, R E; Retyk, W; Ritter, H G; Röhrich, D; Roland, C; Roland, G; Rudolph, H; Rybicki, A; Sammer, T; Sandoval, A; Sann, H; Schäfer, E; Schmidt, R; Schmischke, D; Schmitz, N; Schönfelder, S; Semenov, A Yu; Seyboth, J; Seyboth, P; Seyerlein, J; Siklér, F; Sitár, B; Skrzypczak, E; Squier, G T A; Stelzer, H; Stock, Reinhard; Strmen, P; Ströbele, H; Struck, C; Susa, T; Szarka, I; Szentpétery, I; Szymanski, P; Sziklai, J; Toy, M; Trainor, T A; Trentalange, S; Ullrich, T S; Vassiliou, Maria; Veres, G I; Vesztergombi, G; Vranic, D; Wang, F; Weerasundara, D D; Wenig, S; Whitten, C; Wieman, H H; Wienold, T; Wood, L; Yates, T A; Zimányi, J; Zhu, X Z; Zybert, R

    1999-01-01

    The NA49 detector is a wide acceptance spectrometer for the study of hadron production in p+p, p+A, and A+A collisions at the CERN SPS. The main components are 4 large volume TPCs for tracking and particle identification via $dE/dx$. TOF scintillator arrays complement particle identification. Calorimeters for transverse energy determination and triggering, a detector for centrality selection in p+A collisions, and beam definition detectors complete the set-up. A description of all detector components is given with emphasis on new technical realizations. Performance and operational experience are discussed in particular with respect to the high track density environment of central Pb+Pb collisions.

  2. Liquid scintillator production for the NOvA experiment

    E-print Network

    Mufson, S; Bower, C; Coan, T; Cooper, J; Corwin, L; Karty, J; Mason, P; Pla-Dalmau, A; Proudfoot, M

    2015-01-01

    The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator to its detectors as its active detector medium. The composition of the scintillator was developed to meet the requirements of the experiment. The scintillator was shipped to the NOvA near and far detectors using dedicated stainless steel tanker trailers. A rigorous set of quality control procedures were put in place to assure that the liquid scintillator was blended to satisfy the transparency, light yield, and conductivity requirements. The incoming components, the blended scintillator, and the scintillator in the transport tanker trailers were all qualified with these procedures, which ensured that the NOvA scintillator was high quality and met its performance requirements.

  3. Scintillating Stars

    NSDL National Science Digital Library

    Bob Riddle

    2003-02-01

    Often, a bright planet that is visible over the horizon will be mistaken for a star. Some believe they can tell the difference between a star and a planet because stars twinkle, or scintillate , and planets do not. In actuality however, both will twinkle because any light that passes through our atmosphere, whether it be reflected from a planet or generated by a star, will be interfered with by the atmospheric elements. This month's column sheds light on this "scintillating" subject and engages students in a research activity that revolves around the question: Is Pluto a planet?

  4. The Scintillating Optical Fiber Isotope Experiment

    NASA Technical Reports Server (NTRS)

    Binns, W. Robert

    1988-01-01

    This paper describes the Scintillating Optical Fiber Isotope Experiment (SOFIE) which is being developed by Washington University and the University of New Hampshire to study the abundances of cosmic ray isotopes in the iron charge region. This detector system is a Cerenkov-Range-dE/dx experiment and utilizes range and trajectory detectors made of scintillating optical fibers, a fused silica Cerenkov counter, and plastic scintillator dE/dx counters to determine the charge and mass of cosmic ray nuclei. A brief description of the balloon flight instrument presently being developed will be given followed by initial results of an engineering model calibration at the LBL Bevalac heavy ion accelerator. In addition a brief discussion of the potential of scintillating fiber trajectory detectors for use in experiments requiring precise trajectory determination such as those being planned for the NASA Particle Astrophysics Magnet Facility (Astromag) program is presented.

  5. Nuclear Radiation Detectors

    Microsoft Academic Search

    G. A. Morton

    1962-01-01

    Nuclear radiation detectors are required in all the major fields of nuclear science and technology. They fall into two principal categories, single element detectors and imaging detectors. Single element detectors can be classified into four types, based upon their physical mode of operation. These are 1) Scintillation counters, 2) Gas ionization detectors, a) Ionization chambers, b) Proportional counters, c) Geiger-Mueller

  6. 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 prime requirements. PMID:15156701

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

    Microsoft Academic Search

    Martin P. Tornai; Edward J. Hoffman; Lawrence R. MacDonald; Craig S. Levin

    1996-01-01

    Development of a small area (1-2 cm2) 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

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

    Microsoft Academic Search

    Martin P. Tornai; Edward J. Hoffman; Lawrence R. MacDonald; Craig S. Levin

    1995-01-01

    Development of a small area (1-2 cm2) 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

  9. Towards Implementing Multi-Pixel Photon Counters as Light Detectors for Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Vasquez, Jaime; Saavedra, Arthur; Ramos, Roxana; Tavares, Pablo; Wade, Marcus; Fan, Sewan; Haag, Brooke

    2013-04-01

    There has been tremendous effort in recent years to implement multi-pixel photon counters (MPPC) in diverse areas of particle physics and positron emission tomography. The MPPC detectors possess certain favorable properties such as fast response time, high sensitivity to weak light signals, compact size, low operating voltage, and lower cost compared to photomultiplier tubes. However, constructing a working MPPC detector assembly is not a unique process; there are various working setups. In this poster, we present our particular experimental setup for a working MPPC detector assembly. In particular, we describe our efforts to implement the MPPC as a readout detector to be coupled to wavelength shifting fibers that are implanted within plastic scintillators for the measurement of cosmic rays.

  10. Scintillator counters with WLS fiber\\/MPPC readout for the side muon range detector (SMRD) of the T2K experiment

    Microsoft Academic Search

    A. Izmaylov; S. Aoki; J. Blocki; J. Brinson; A. Dabrowska; I. Danko; M. Dziewiecki; B. Ellison; L. Golyshkin; R. Gould; T. Hara; B. Hartfiel; J. Holeczek; M. Khabibullin; A. Khotjantsev; D. Kielczewska; J. Kisiel; T. Kozlowski; Yu. Kudenko; R. Kurjata; T. Kutter; J. Lagoda; J. Liu; J. Marzec; W. Metcalf; P. Mijakowski; O. Mineev; Yu. Musienko; D. Northacker; M. Nauman; J. Nowak; V. Paolone; M. Posiadala; P. Przewlocki; J. Reid; E. Rondio; A. Shaykhiev; M. Sienkiewicz; D. Smith; J. Sobczyk; M. Stodulski; A. Straczek; R. Sulej; A. Suzuki; J. Swierblewski; T. Szeglowski; M. Szeptycka; T. Wachala; D. Warner; N. Yershov; T. Yano; A. Zalewska; K. Zaremba; M. Ziembicki

    2010-01-01

    The T2K neutrino experiment at J-PARC uses a set of near detectors to measure the properties of an unoscillated neutrino beam and neutrino interaction cross-sections. One of the sub-detectors of the near-detector complex, the side muon range detector (SMRD), is described in the paper. The detector is designed to help measure the neutrino energy spectrum, to identify background and to

  11. 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.

  12. Secondary scintillation yield in pure argon

    NASA Astrophysics Data System (ADS)

    Monteiro, C. M. B.; Lopes, J. A. M.; Veloso, J. F. C. A.; dos Santos, J. M. F.

    2008-10-01

    The secondary scintillation yield is of great importance for simulating double phase detectors, which are used in several of the ongoing Dark Matter search experiments, as well as in the future large-scale particle detectors proposed in Europe as the next generation underground observatories. The argon secondary scintillation yield is studied, at room temperature, as a function of electric field in the gas scintillation gap. A Large Area Avalanche Photodiode (LAAPD) collects the VUV secondary scintillation produced in the gas, as well as the 5.9 keV x-rays directly absorbed in the photodiode. The direct x-rays were used as a reference for the determination of the number of charge carriers produced by the scintillation pulse and, so, the number of photons impinging the LAAPD. A value of 81 photons/kV was obtained for the scintillation amplification parameter, defined as the number of photons produced per drifting electron and per kilovolt. The scintillation yields obtained in this work are in agreement with those obtained by Monte Carlo calculations and a factor of ?10 higher than those determined by the WARP experiment.

  13. Scintillating double-beta-decay bolometers

    SciTech Connect

    Pirro, S. [Dipartimento di Fisica dell'Universita di Milano-Bicocca and INFN (Italy)], E-mail: Stefano.Pirro@mib.infn.it; Beeman, J. W. [Lawrence Berkeley National Laboratory (United States); Capelli, S.; Pavan, M.; Previtali, E. [Dipartimento di Fisica dell'Universita di Milano-Bicocca and INFN (Italy); Gorla, P. [Laboratori Nazionali del Gran Sasso (Italy)

    2006-12-15

    We present the results obtained in the development of scintillating double-beta-decay bolometers. Several Mo and Cd based crystals were tested with the bolometric technique. The scintillation light was measured through a second independent bolometer. A 140-g CdWO{sub 4} crystal was run in a 417-h live time measurement. Thanks to the scintillation light, the {alpha} background is easily discriminated, resulting in zero counts above the 2615-keV {gamma} line of {sup 208}Tl. These results, combined with an extreme easy light detector operation, represent the first tangible proof demonstrating the feasibility of this kind of technique.

  14. 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.

  15. GPS and ionospheric scintillations

    Microsoft Academic Search

    P. M. Kintner; B. M. Ledvina; E. R. de Paula

    2007-01-01

    Ionospheric scintillations are one of the earliest known effects of space weather. Caused by ionization density irregularities, scintillating signals change phase unexpectedly and vary rapidly in amplitude. GPS signals are vulnerable to ionospheric irregularities and scintillate with amplitude variations exceeding 20 dB. GPS is a weak signal system and scintillations can interrupt or degrade GPS receiver operation. For individual signals,

  16. Optical Design Considerations for Efficient Light Collection from Liquid Scintillation Counters

    SciTech Connect

    Bernacki, Bruce E.; Douglas, Matthew; Erchinger, Jennifer L.; Fuller, Erin S.; Keillor, Martin E.; Morley, Shannon M.; Mullen, Crystal A.; Orrell, John L.; Panisko, Mark E.; Warren, Glen A.; Wright, Michael E.

    2015-01-01

    Liquid scintillation counters measure charged particle-emitting radioactive isotopes and are used for environmental studies, nuclear chemistry, and life science. Alpha and beta emissions arising from the material under study interact with the scintillation cocktail to produce light. The prototypical liquid scintillation counter employs low-level photon-counting detectors to measure the arrival of the scintillation light produced as a result of the dissolved material under study interacting with the scintillation cocktail. For reliable operation the counting instrument must convey the scintillation light to the detectors efficiently and predictably. Current best practices employ the use of two or more detectors for coincidence processing to discriminate true scintillation events from background events due to instrumental effects such as photomultiplier tube dark rates, tube flashing, or other light emission not generated in the scintillation cocktail vial. In low background liquid scintillation counters additional attention is paid to shielding the scintillation cocktail from naturally occurring radioactive material (NORM) present in the laboratory and within the instruments construction materials. Low background design is generally at odds with optimal light collection. This study presents the evolution of a light collection design for liquid scintillation counting in a low background shield. The basic approach to achieve both good light collection and a low background measurement is described. The baseline signals arising from the scintillation vial are modeled and methods to efficiently collect scintillation light are presented as part of the development of a customized low-background, high sensitivity liquid scintillation counting system.

  17. Properties of 100-mm X 100-mm triple stacks of microchannel plates used in a sealed detector for x-ray crystallography

    Microsoft Academic Search

    Mark B. Williams; Stanley E. Sobottka; John A. Shepherd

    1993-01-01

    We report the assembly of an imaging phototube which, together with a thin NaI(Tl) x-ray scintillator, forms a photon counting area detector for x-ray crystallography. The tube contains a bialkali photocathode, a triple (Z) stack of 100 mm X 100 mm MCPs, and a 133 mm X 133 mm two dimensional delay line readout. Some aspects of the processing setup

  18. Setup in the surfzone

    E-print Network

    Apotsos, Alex

    2007-01-01

    Surfzone wave height transformation and wave-breaking-driven increases in the mean sea level (setup) are examined on alongshore-uniform beaches with alongshore homogeneous and inhomogeneous wave forcing. While previously ...

  19. Guitar Intonation & Setup

    NSDL National Science Digital Library

    This PowerPoint document provides a basic introduction to guitar intonation and setup. The presentation covers standard tuning, installing the nut and strings, neck relief and intonation. The presentation also includes illustrative diagrams and photographs.

  20. Low-power Charge Sensitive Amplifier for Semiconductor Scintillator

    E-print Network

    Stanacevic, Milutin

    was implemented in 0.5µm CMOS process with a 5 V power supply. I. INTRODUCTION There is a great needLow-power Charge Sensitive Amplifier for Semiconductor Scintillator Xiao Yun, Milutin Stana) for measurement of optical response of photo-detector reg- istering light produced by semiconductor scintillator

  1. Investigating the energy resolution of arrays of small scintillation crystals

    Microsoft Academic Search

    D. J. Herbert; L. J. Meng; D. Ramsden

    2002-01-01

    Arrays of small scintillation crystals are being used increasingly for high-resolution imaging applications in nuclear medicine. Although the degree of pixellation now available is high for some scintillation materials, this spatial resolution is often achieved at the expense of degraded energy resolution due to the lower, and more variable, light-collection efficiency. The energy resolution of a detector is, however, especially

  2. Design of an Instrument to Measure Optical Reflectance of Scintillating Crystal Surfaces

    Microsoft Academic Search

    Martin Janecek; William W. Moses

    2008-01-01

    In order for a Monte Carlo simulation to be accurate in predicting and optimizing the light collection in scintillation detectors, the light reflectance off an internal surface within the scintillating crystal must be understood well. We present design studies for an instrument that will accurately measure the reflectance distribution within a scintillating crystal. A laser is aimed towards the center

  3. GEM scintillation readout with avalanche photodiodes

    NASA Astrophysics Data System (ADS)

    Conceição, A. S.; Requicha Ferreira, L. F.; Fernandes, L. M. P.; Monteiro, C. M. B.; Coelho, L. C. C.; Azevedo, C. D. R.; Veloso, J. F. C. A.; Lopes, J. A. M.; dos Santos, J. M. F.

    2007-09-01

    The use of the scintillation produced in the charge avalanches in GEM holes as signal amplification and readout is investigated for xenon. A VUV-sensitive avalanche photodiode has been used as photosensor. Detector gains of about 4 × 104 are achieved in scintillation readout mode, for GEM voltages of 490 V and for a photosensor gain of 150. Those gains are more than one order of magnitude larger than what is obtained using charge readout. In addition, the energy resolutions achieved with the scintillation readout are lower than those achieved with charge readout. The GEM scintillation yield in xenon was measured as a function of GEM voltage, presenting values that are about a half of those achieved for the charge yield, and reach about 730 photons per primary electron at GEM voltages of 490 V.

  4. Buried plastic scintillator muon telescope

    NASA Astrophysics Data System (ADS)

    Sanchez, F.; Medina-Tanco, G. A.; D'Olivo, J. C.; et al.

    Muon telescopes can have several applications, ranging from astrophysical to solar-terrestrial interaction studies, and fundamental particle physics. We show the design parameters, characterization and end-to-end simulations of a detector composed by a set of three parallel dual-layer scintillator planes, buried at fix depths ranging from 0.30 m to 3 m. Each layer is 4 m2 and is composed by 50 rectangular pixels of 4cm x 2 m, oriented at a 90 deg angle with respect to its companion layer. The scintillators are MINOS extruded polystyrene strips with two Bicron wavelength shifting fibers mounted on machined grooves. Scintillation light is collected by multi-anode PMTs of 64 pixels, accommodating two fibers per pixel. The front-end electronics has a time resolution of 7.5 nsec. Any strip signal above threshold opens a GPS-tagged 2 micro-seconds data collection window. All data, including signal and background, are saved to hard disk. Separation of extensive air shower signals from secondary cosmic-ray background muons and electrons is done offline using the GPS-tagged threefold coincidence signal from surface water cerenkov detectors located nearby in a triangular array. Cosmic-ray showers above 6 PeV are selected. The data acquisition system is designed to keep both, background and signals from extensive air showers for a detailed offline data.

  5. Energy resolution of gamma-ray spectroscopy of JET plasmas with a LaBr{sub 3} scintillator detector and digital data acquisition

    SciTech Connect

    Nocente, M.; Tardocchi, M.; Grosso, G.; Perelli Cippo, E.; Pietropaolo, A.; Proverbio, I.; Gorini, G. [Dipartimento di Fisica, Universita degli Studi di Milano-Bicocca and Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, 20125 Milano (Italy); Chugunov, I.; Gin, D.; Shevelev, A. [A. F. Ioffe Physico-Technical Institute, St. Petersburg 194021 (Russian Federation); Pereira, R. C.; Fernandes, A. M.; Neto, A.; Sousa, J. [Associacao EURATOM/IST Centro de Fusao Nuclear, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Edlington, T.; Kiptily, V.; Syme, B. [Culham Centre for Fusion Energy, Culham OX143DB (United Kingdom); Murari, A. [Consorzio RFX, 35127 Padova (Italy); Collaboration: JET-EFDA Contributors

    2010-10-15

    A new high efficiency, high resolution, fast {gamma}-ray spectrometer was recently installed at the JET tokamak. The spectrometer is based on a LaBr{sub 3}(Ce) scintillator coupled to a photomultiplier tube. A digital data acquisition system is used to allow spectrometry with event rates in excess of 1 MHz expected in future JET DT plasmas. However, at the lower rates typical of present day experiments, digitization can degrade the energy resolution of the system, depending on the algorithms used for extracting pulse height information from the digitized pulses. In this paper, the digital and analog spectrometry methods were compared for different experimental conditions. An algorithm based on pulse shape fitting was developed, providing energy resolution equivalent to the traditional analog spectrometry method.

  6. Bolometric calibration of a superfluid $^3$He detector for Dark Matter search: direct measurement of the scintillated energy fraction for neutron, electron and muon events

    E-print Network

    C. B. Winkelmann; J. Elbs; Yu. M. Bunkov; E. Collin; H. Godfrin; M. Krusius

    2006-11-28

    We report on the calibration of a superfluid $^3$He bolometer developed for the search of non-baryonic Dark Matter. Precise thermometry is achieved by the direct measurement of thermal excitations using Vibrating Wire Resonators (VWRs). The heating pulses for calibration were produced by the direct quantum process of quasiparticle generation by other VWRs present. The bolometric calibration factor is analyzed as a function of temperature and excitation level of the sensing VWR. The calibration is compared to bolometric measurements of the nuclear neutron capture reaction and heat depositions by cosmic muons and low energy electrons. The comparison allows a quantitative estimation of the ultra-violet scintillation rate of irradiated helium, demonstrating the possibility of efficient electron recoil event rejection.

  7. Energy resolution of gamma-ray spectroscopy of JET plasmas with a LaBr3 scintillator detector and digital data acquisition.

    PubMed

    Nocente, M; Tardocchi, M; Chugunov, I; Pereira, R C; Edlington, T; Fernandes, A M; Gin, D; Grosso, G; Kiptily, V; Murari, A; Neto, A; Perelli Cippo, E; Pietropaolo, A; Proverbio, I; Shevelev, A; Sousa, J; Syme, B; Gorini, G

    2010-10-01

    A new high efficiency, high resolution, fast ?-ray spectrometer was recently installed at the JET tokamak. The spectrometer is based on a LaBr3(Ce) scintillator coupled to a photomultiplier tube. A digital data acquisition system is used to allow spectrometry with event rates in excess of 1 MHz expected in future JET DT plasmas. However, at the lower rates typical of present day experiments, digitization can degrade the energy resolution of the system, depending on the algorithms used for extracting pulse height information from the digitized pulses. In this paper, the digital and analog spectrometry methods were compared for different experimental conditions. An algorithm based on pulse shape fitting was developed, providing energy resolution equivalent to the traditional analog spectrometry method. PMID:21058454

  8. 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.

  9. Gamma ray detector shield

    DOEpatents

    Ohlinger, R.D.; Humphrey, H.W.

    1985-08-26

    A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

  10. Scintillation light emission studies of LSO scintillators

    Microsoft Academic Search

    A. Saoudi; C. Pepin; D. Houde; R. Lecomte

    1999-01-01

    UV and ?-ray excited luminescence and nuclear spectroscopy were used to study the relationship between the scintillation mechanisms of LSO and the spectroscopic characteristics obtained with PMT and APD readouts at room temperature. No correlation was found between scintillation decay time and light output. Like other investigators, we observed the existence of two distinct luminescence centers, Ce1 and Ce2, that

  11. Scintillator materials for calorimetry

    SciTech Connect

    Weber, M.J. [Lawrence Berkeley Lab., CA (United States). Life Sciences Div.

    1994-09-01

    Requirements for fast, dense scintillator materials for calorimetry in high energy physics and approaches to satisfying these requirements are reviewed with respect to possible hosts and luminescent species. Special attention is given to cerium-activated crystals, core-valence luminescence, and glass scintillators. The present state of the art, limitations, and suggestions for possible new scintillator materials are presented.

  12. Scintillator manufacture at Fermilab

    SciTech Connect

    Mellott, K.; Bross, A.; Pla-Dalmau, A. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)

    1998-11-09

    A decade of research into plastic scintillation materials at Fermilab is reviewed. Early work with plastic optical fiber fabrication is revisited and recent experiments with large-scale commercial methods for production of bulk scintillator are discussed. Costs for various forms of scintillator are examined and new development goals including cost reduction methods and quality improvement techniques are suggested.

  13. Scintillator manufacture at Fermilab

    SciTech Connect

    Mellott, K.; Bross, A.; Pla-Dalmau, A.

    1998-08-01

    A decade of research into plastic scintillation materials at Fermilab is reviewed. Early work with plastic optical fiber fabrication is revisited and recent experiments with large-scale commercial methods for production of bulk scintillator are discussed. Costs for various forms of scintillator are examined and new development goals including cost reduction methods and quality improvement techniques are suggested.

  14. Studies of light collection in depolished inorganic scintillators using Monte Carlo Simulations

    SciTech Connect

    Altamirano, A. [Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia (Peru); Centro de Tecnologias de Informacion y Comunicaciones, UNI, Lima (Peru); Salinas, C. J. Solano [Instituto de Fisica, Universidad Nacional de Ingenieria, Lima (Peru); Centro de Tecnologias de Informacion y Comunicaciones, UNI, Lima (Peru); Wahl, D. [Instituto de Fisica, Universidad Nacional de Ingenieria, Lima (Peru)

    2009-04-30

    Scintillators are materials which emit light when energetic particles deposit energy in their volume. It is a quasi-universal requirement that the light detected in scintillator setups be maximised. The following project aims to study how the light collection is affected by surface depolishing using the simulation programs GEANT4 and LITRANI.

  15. UKDMC Dark Matter Search with Inorganic Scintillators

    Microsoft Academic Search

    V. A. Kudryavtsev; N. J. C. Spooner; P. K. Lightfoot; J. W. Roberts; M. J. Lehner; T. Gamble; T. B. Lawson; R. Lüscher; J. E. McMillan; M. Robinson; D. R. Tovey; N. J. T. Smith; P. F. Smith; G. J. Alner; S. P. Hart; J. D. Lewin; R. M. Preece; T. J. Sumner; W. G. Jones; J. J. Quenby; B. Ahmed; A. Bewick; D. Davidge; J. V. Dawson; A. S. Howard; I. Ivaniouchenkov; M. K. Joshi; V. Lebedenko; I. Liubarsky; J. C. Barton

    2001-01-01

    The status of dark matter searches with inorganic scintillator detectors at Boulby mine is reviewed. Results of a test experiment with CsI(Tl) crystal are presented. The objectives of this experiment were to study anomalous fast events and ways to remove this background. We found clear indications that these events were due to surface contami- nation of crystals by alphas, probably

  16. The Oriented Scintillation Spectrometer Experiment - Instrument description

    Microsoft Academic Search

    W. N. Johnson; R. L. Kinzer; J. D. Kurfess; M. S. Strickman; W. R. Purcell; D. A. Grabelsky; M. P. Ulmer; D. A. Hillis; G. V. Jung; R. A. Cameron

    1993-01-01

    The Oriented Scintillation Spectrometer Experiment on the Arthur Holly Compton Gamma Ray Observatory satellite uses four actively shielded NaI (Tl)-CsI(Na) phoswich detectors to provide gamma-ray line and continuum detection capability in the 0.05-10 MeV energy range. The instrument includes secondary capabilities for gamma-ray and neutron detection between 10 and 250 MeV. The detectors have 3.8 deg x 11.04 deg (FWHM)

  17. Setup for testing LHCb Inner Tracker Modules

    E-print Network

    P. Vazquez Regueiro; D. Esperante Pereira; H. Voss; L. Nicolas

    2010-10-18

    The Inner Tracker of the LHCb experiment is a silicon microstrip detector consisting of 336 detector modules with either one or two sensors. The module production is now underway and we present here the setup employed for module testing during the production. The setup is based on the same electronics that will be used in the final experiment. We perform burn-in and ageing tests with the help of a custom made Temperature Cycling Box controlled with LabVIEW under Windows. The DAQ is done in another PC running Linux. Here we integrate the different C/C++ libraries used to communicate to the LHCb Time and Fast Control system,Experiment Control System and Data Acquisition.

  18. Scintillator reflective layer coextrusion

    DOEpatents

    Yun, Jae-Chul (Naperville, IL); Para, Adam (St. Charles, IL)

    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.

  19. LUMINEU: A Pilot Scintillating Bolometer Experiment for Neutrinoless Double Beta Decay Search

    NASA Astrophysics Data System (ADS)

    Tenconi, M.

    The Luminescent Underground Molybdenum Investigation for NEUtrino mass and nature (LUMINEU) aims at preparing the ground for a next-generation neutrinoless double beta decay experiment employing scintillating bolometers: these devices are in fact very promising tools in rare events search, in terms of e ciency, energy resolution and background control. In particular, they can tag alpha events, which are the dominant residual background for double beta decay candidates with a transition energy higher than 2615 keV. LUMINEU's goal is the operation of a pilot detector, consisting of four 400 g ZnMoO4 scintillating bolometers, probing an active 100Mo mass of about 0.7 kg, the energy transition of this isotope being 3034 keV. The enriched material for this setup is available and the experiment is fully funded by ANR in France. This preliminary investigation intends to be feasibility test for a next-generation neutrinoless double beta decay experiment aiming at probing the inverted hierarchy region of the neutrino mass pattern. LUMINEU will help to fix the detailed structure of the single module of this future large-scale experiment. The ZnMoO4 crystals will be grown at the Nikolaev Institute for Inorganic Chemistry in Novosibirsk, Russia. LUMINEU foresees a systematic optimization of the crystal growth parameters, in order to optimize the bolometric performance, the light yield, the particle rejection factor and the radiopurity of the scintillating bolometers. On this purpose, an aboveground facility was set up at the Centre de Sciences Nucleaire? et de Sciences de la Matiere' (CSNSM), in Orsay, France. In this contribution, we will describe the LUMINEU program, we will discuss its sensitivity and that one of a future large search based on this technology. We will also present preliminary experimental results achieved in Orsay with scintillating bolometers fabricated employing the first LUMINEU ZnMoO4 crystals, which have been delivered in June 2013.

  20. Results from the HERMES Recoil Detector Sergey Yaschenko

    E-print Network

    Scintillating Fiber Tracker (SFT) 2 barrels of scintillation fibers with 2 parallel and 2 stereo layers Lepton Scintillating Fiber Tracker (SFT) 2 cylinders: ­ 2 layers parallel to the beam axis ­ 2 stereo layers at 10 Detector Status All sub-detectors are calibrated ­ SFT and PD with positively and negatively charged pions

  1. Samarkand complex setup for investigation of cosmic ray variation in the energy range of 7 10 (9) - 10 (15) eV

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.

    1985-08-01

    The Samarkand complex setup is aimed at the study of cosmic ray variations in a wide energy range from 7 billion eV (which corresponds to the geomagnetic threshold in the region of Samarkand) up to approx 10 to the 15th power to 10 to the 16th power eV. The setup consists of four 6-counter sections of neutron supermonitor with counters SNM-15 and 48 scintillator detectors (1 sq m each) placed under and above the supermonitor. The effective area of the setup for recording neutrons and muons is 24 sq m. The setup can register time variations of the following cosmic ray components: (1) the total neutron counting rate, (2) counting rates for neutrons of different multiplicity, (3) soft-muon fluxes, (4) hard-muon fluxes at various zenith and azimuth angles, (5) electron-photon component, (6) extensive air showers (EAS) induced by primary particles in a wide energy range and accompanied or not accompanied by muons and neutrons.

  2. A beta dosimeter and spectrometer utilizing plastic scintillators and a large-area avalanche photodiode

    Microsoft Academic Search

    Aaron A. Kriss

    2004-01-01

    The purpose of this research was to develop and test a radiation detector to perform beta dosimetry and spectroscopy. The detector utilizes plastic scintillator volumes to produce scintillation light in proportion to the amount of energy deposited in them, and a large-area avalanche photodiode to convert the light to electrical signals. Pulse processing electronics transform the electrical signals into a

  3. Multi-PSPMT scintillation camera

    SciTech Connect

    Pani, R.; Pellegrini, R.; Trotta, G.; Scopinaro, F. [Univ. of Rome (Italy). Dept. of Experimental Medicine] [Univ. of Rome (Italy). Dept. of Experimental Medicine; Soluri, A.; Vincentis, G. de [CNR (Italy). Inst. of Biomedical Technologies] [CNR (Italy). Inst. of Biomedical Technologies; Scafe, R. [ENEA-INN, Rome (Italy)] [ENEA-INN, Rome (Italy); Pergola, A. [PSDD, Rome (Italy)] [PSDD, Rome (Italy)

    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.

  4. Neutron scintillators using wavelength shifting fibers

    SciTech Connect

    Hutchinson, D.P.; Miller, V.C.; Ramsey, J.A.

    1995-06-01

    A proposed design for an optically-based, one-dimension scintillation detector to replace the gas-filled position-sensitive proportional counter currently used for a wide-angle neutron detector (WAND) at the high-Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) is presented. The scintillator, consisting of a mixture of {sup 6}LiF and ZnS(Ag) powders in an epoxy binder, is coupled to an array of wavelength shifting optical fibers which provide position resolution. The wide-angle neutron detector is designed to cover a 120 degree arc with a 75 cm radius of curvature. The final detector design provides for 600 optical fibers coupled to the scintillator screen with an angular resolution of 0.2 degrees. Each individual pixel of the detector will be capable of operating at count rates exceeding 1 MHz. Results are presented from the measurement of neutron conversion efficiencies for several screen compositions, gamma-ray sensitivity, and spatial resolution of a 16 element one-dimensional array prototype.

  5. Neutrino Detectors: Challenges and Opportunities

    SciTech Connect

    Soler, F. J. P. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2011-10-06

    This paper covers possible detector options suitable at future neutrino facilities, such as Neutrino Factories, Super Beams and Beta Beams. The Magnetised Iron Neutrino Detector (MIND), which is the baseline detector at a Neutrino Factory, will be described and a new analysis which improves the efficiency of this detector at low energies will be shown. Other detectors covered include the Totally Active Scintillating Detectors (TASD), particularly relevant for a low energy Neutrino Factory, emulsion detectors for tau detection, liquid argon detectors and megaton scale water Cherenkov detectors. Finally the requirements of near detectors for long-baseline neutrino experiments will be demonstrated.

  6. The COMPASS Setup for Physics with Hadron Beams

    E-print Network

    Abbon, Ph.; Akhunzyanov, R.; Alexandrov, Yu.; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Buchele, M.; Burtin, E.; Capozza, L.; Ciliberti, P.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Cotte, D.; Crespo, M.L.; Curiel, Q.; Dafni, T.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Desforge, D.; Dinkelbach, A.M.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Durand, D.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; M. Finger jr; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Gatignon, L.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giganon, A.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmuller, S.; Grasso, A.; Gregori, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F.H.; Herrmann, F.; Hinterberger, F.; Hoppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Jorg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kroumchtein, Z.V.; Kuchinski, N.; Kuhn, R.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.K.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Menon, G.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Moinester, M.A.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Novy, J.; Nowak, W.D.; Nunes, Ana Sofia; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pesaro, G.; Pesaro, V.; Peshekhonov, D.V.; Pires, C.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Reymond, J-M.; Rocco, E.; Rossiyskaya, N.S.; Rousse, J.Y.; Ryabchikov, D.I.; Rychter, A.; Samartsev, A.; Samoylenko, V.D.; Sandacz, A.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schluter, T.; Schmidt, K.; Schmieden, H.; Schonning, K.; Schopferer, S.; Schott, M.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Wolbeek, J. ter; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tskhay, V.; Uhl, S.; Uman, I.; Virius, M.; Wang, L.; Weisrock, T.; Weitzel, Q.; Wilfert, M.; Windmolders, R.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

    2014-01-01

    The main characteristics of the COMPASS experimental setup for physics with hadron beams are described. This setup was designed to perform exclusive measurements of processes with several charged and/or neutral particles in the final state. Making use of a large part of the apparatus that was previously built for spin structure studies with a muon beam, it also features a new target system as well as new or upgraded detectors. The hadron setup is able to operate at the high incident hadron flux available at CERN. It is characterised by large angular and momentum coverages, large and nearly flat acceptances, and good two and three-particle mass resolutions. In 2008 and 2009 it was successfully used with positive and negative hadron beams and with liquid hydrogen and solid nuclear targets. This article describes the new and upgraded detectors and auxiliary equipment, outlines the reconstruction procedures used, and summarises the general performance of the setup.

  7. The COMPASS Setup for Physics with Hadron Beams

    E-print Network

    Ph. Abbon; C. Adolph; R. Akhunzyanov; Yu. Alexandrov; M. G. Alexeev; G. D. Alexeev; A. Amoroso; V. Andrieux; V. Anosov; A. Austregesilo; B. Badelek; F. Balestra; J. Barth; G. Baum; R. Beck; Y. Bedfer; A. Berlin; J. Bernhard; K. Bicker; E. R. Bielert; J. Bieling; R. Birsa; J. Bisplinghoff; M. Bodlak; M. Boer; P. Bordalo; F. Bradamante; C. Braun; A. Bressan; M. Buechele; E. Burtin; L. Capozza; P. Ciliberti; M. Chiosso; S. U. Chung; A. Cicuttin; M. Colantoni; D. Cotte; M. L. Crespo; Q. Curiel; T. Dafni; S. Dalla Torre; S. S. Dasgupta; S. Dasgupta; O. Yu. Denisov; D. Desforge; A. M. Dinkelbach; S. V. Donskov; N. Doshita; V. Duic; W. Duennweber; D. Durand; M. Dziewiecki; A. Efremov; C. Elia; P. D. Eversheim; W. Eyrich; M. Faessler; A. Ferrero; M. Finger; M. Finger jr.; H. Fischer; C. Franco; N. du Fresne von Hohenesche; J. M. Friedrich; V. Frolov; L. Gatignon; F. Gautheron; O. P. Gavrichtchouk; S. Gerassimov; R. Geyer; A. Giganon; I. Gnesi; B. Gobbo; S. Goertz; M. Gorzellik; S. Grabmueller; A. Grasso; M. Gregori; B. Grube; T. Grussenmeyer; A. Guskov; F. Haas; D. von Harrach; D. Hahne; R. Hashimoto; F. H. Heinsius; F. Herrmann; F. Hinterberger; Ch. Hoeppner; N. Horikawa; N. d'Hose; S. Huber; S. Ishimoto; A. Ivanov; Yu. Ivanshin; T. Iwata; R. Jahn; V. Jary; P. Jasinski; P. Joerg; R. Joosten; E. Kabuss; B. Ketzer; G. V. Khaustov; Yu. A. Khokhlov; Yu. Kisselev; F. Klein; K. Klimaszewski; J. H. Koivuniemi; V. N. Kolosov; K. Kondo; K. Koenigsmann; I. Konorov; V. F. Konstantinov; A. M. Kotzinian; O. Kouznetsov; M. Kraemer; Z. V. Kroumchtein; N. Kuchinski; R. Kuhn; F. Kunne; K. Kurek; R. P. Kurjata; A. A. Lednev; A. Lehmann; M. Levillain; S. Levorato; J. Lichtenstadt; A. Maggiora; A. Magnon; N. Makke; G. K. Mallot; C. Marchand; J. Marroncle; A. Martin; J. Marzec; J. Matousek; H. Matsuda; T. Matsuda; G. Menon; G. Meshcheryakov; W. Meyer; T. Michigami; Yu. V. Mikhailov; Y. Miyachi; M. A. Moinester; A. Nagaytsev; T. Nagel; F. Nerling; S. Neubert; D. Neyret; V. I. Nikolaenko; J. Novy; W. -D. Nowak; A. S. Nunes; A. G. Olshevsky; I. Orlov; M. Ostrick; R. Panknin; D. Panzieri; B. Parsamyan; S. Paul; G. Pesaro; V. Pesaro; D. V. Peshekhonov; C. Pires; S. Platchkov; J. Pochodzalla; V. A. Polyakov; J. Pretz; M. Quaresma; C. Quintans; S. Ramos; C. Regali; G. Reicherz; J-M. Reymond; E. Rocco; N. S. Rossiyskaya; J. -Y. Rousse; D. I. Ryabchikov; A. Rychter; A. Samartsev; V. D. Samoylenko; A. Sandacz; S. Sarkar; I. A. Savin; G. Sbrizzai; P. Schiavon; C. Schill; T. Schlueter; K. Schmidt; H. Schmieden; K. Schoenning; S. Schopferer; M. Schott; O. Yu. Shevchenko; L. Silva; L. Sinha; S. Sirtl; M. Slunecka; S. Sosio; F. Sozzi; A. Srnka; L. Steiger; M. Stolarski; M. Sulc; R. Sulej; H. Suzuki; A. Szabelski; T. Szameitat; P. Sznajder; S. Takekawa; J. ter Wolbeek; S. Tessaro; F. Tessarotto; F. Thibaud; V. Tskhay; S. Uhl; I. Uman; M. Virius; L. Wang; T. Weisrock; Q. Weitzel; M. Wilfert; R. Windmolders; H. Wollny; K. Zaremba; M. Zavertyaev; E. Zemlyanichkina; M. Ziembicki; A. Zink

    2014-10-07

    The main characteristics of the COMPASS experimental setup for physics with hadron beams are described. This setup was designed to perform exclusive measurements of processes with several charged and/or neutral particles in the final state. Making use of a large part of the apparatus that was previously built for spin structure studies with a muon beam, it also features a new target system as well as new or upgraded detectors. The hadron setup is able to operate at the high incident hadron flux available at CERN. It is characterised by large angular and momentum coverages, large and nearly flat acceptances, and good two and three-particle mass resolutions. In 2008 and 2009 it was successfully used with positive and negative hadron beams and with liquid hydrogen and solid nuclear targets. This article describes the new and upgraded detectors and auxiliary equipment, outlines the reconstruction procedures used, and summarises the general performance of the setup.

  8. Energy partition in sapphire and BGO scintillating bolometers

    NASA Astrophysics Data System (ADS)

    Ortigoza, Y.; Coron, N.; Cuesta, C.; García, E.; Ginestra, C.; Gironnet, J.; de Marcillac, P.; Martínez, M.; Pobes, C.; Puimedón, J.; Redon, T.; Sarsa, M. L.; Torres, L.; Villar, J. A.

    2011-03-01

    Scintillating bolometers are particle detectors with a high particle discrimination power with many applications in nuclear and particle physics. This discrimination power is based on the different scintillation yield for different particles, and is strongly dependent on the target used. At the very low temperatures required for the operation of the bolometers, very few data about the scintillation yields are available. In this paper we present estimates of absolute light yields and energy partition among heat, light and trapping channels in Sapphire (Al 2O 3) and BGO (Bi 4Ge 3O 12) scintillating bolometers operated at 20 mK. The estimate relies on the observed negative correlation between the light and heat signals produced by ?-ray absorption in scintillating bolometers and on the study of the X-ray stimulated luminescence properties of BGO at temperatures down to 77 K.

  9. Measurement of ortho-positronium properties in liquid scintillators

    NASA Astrophysics Data System (ADS)

    Perasso, S.; Consolati, G.; Franco, D.; Hans, S.; Jollet, C.; Meregaglia, A.; Tonazzo, A.; Yeh, M.

    2013-08-01

    Pulse shape discrimination in liquid scintillator detectors is a well-established technique for the discrimination of heavy particles from light particles. Nonetheless, it is not efficient in the separation of electrons and positrons, as they give rise to indistinguishable scintillator responses. This inefficiency can be overtaken through the exploitation of the formation of ortho-Positronium (o-Ps), which alters the time profile of light pulses induced by positrons. We characterized the o-Ps properties in the most commonly used liquid scintillators, i.e. PC, PXE, LAB, OIL and PC + PPO. In addition, we studied the effects of scintillator doping on the o-Ps properties for dopants currently used in neutrino experiments, Gd and Nd. Further measurements for Li-loaded and Tl-loaded liquid scintillators are foreseen. We found that the o-Ps properties are suitable for enhancing the electron-positron discrimination.

  10. Arsenic activation neutron detector

    DOEpatents

    Jacobs, Eddy L. (Albuquerque, NM)

    1981-01-01

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5 Mev neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  11. Arsenic activation neutron detector

    DOEpatents

    Jacobs, E.L.

    1980-01-28

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5-MeV neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  12. The features of electronics structure of the multichannel scintillation module for the EMMA experiment

    NASA Astrophysics Data System (ADS)

    Volchenko, V.; Volchenko, G.; Akhrameev, E.; Bezrukov, L.; Dzaparova, I.; Enqvist, T.; Inzhechik, L.; Izmaylov, A.; Joutsenvaara, J.; Khabibullin, M.; Khotjantsev, A.; Kuusiniemi, P.; Lubsandorzhiev, B.; Mineev, O.; Petkov, V.; Poleshuk, R.; Shaibonov, B.; Sarkamo, J.; Shaykhiev, A.; Trzaska, W.; Yanin, A.; Yershov, N.

    2011-05-01

    A brief description of the developed structural electric diagrams of 16-channel scintillation module for the underground EMMA experiment, the basic characteristics and parameters of the electrical diagrams of this module are presented. Multi-pixel photodiodes operating in a limited Geiger mode are used for photoreadout of the scintillator detectors in 16-channel scintillation module. The method of the automatic tuning of the photosensors gain based on the stabilization of an average counting rate of the scintillation detectors from gamma rays of a natural radioactive background is described.

  13. Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

    NASA Astrophysics Data System (ADS)

    Aberle, C.; Buck, C.; Gramlich, B.; Hartmann, F. X.; Lindner, M.; Schönert, S.; Schwan, U.; Wagner, S.; Watanabe, H.

    2012-06-01

    Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.

  14. Review on photonic crystal coatings for scintillators

    NASA Astrophysics Data System (ADS)

    Knapitsch, Arno; Lecoq, Paul

    2014-11-01

    The amount of light and its time distribution are key factors determining the performance of scintillators when used as radiation detectors. However most inorganic scintillators are made of heavy materials and suffer from a high index of refraction which limits light extraction efficiency. This increases the path length of the photons in the material with the consequence of higher absorption and tails in the time distribution of the extracted light. Photonic crystals are a relatively new way of conquering this light extraction problem. Basically they are a way to produce a smooth and controllable index matching between the scintillator and the output medium through the nanostructuration of a thin layer of optically transparent high index material deposited at the coupling face of the scintillator. Our review paper discusses the theory behind this approach as well as the simulation details. Furthermore the different lithography steps of the production of an actual photonic crystal sample will be explained. Measurement results of LSO scintillator pixels covered with a nanolithography machined photonic crystal surface are presented together with practical tips for the further development and improvement of this technique.

  15. Tracking with scintillating fibers

    NASA Astrophysics Data System (ADS)

    Ruchti, R.

    1995-11-01

    The parametric performance of scintillating fiber tracking elements is reviewed and compared with recent measurements. Topics include performance of scintillation materials, single-clad and multiclad fiber waveguide structures, optical splicing, and photosensors. A brief description of fiber trackers utilized in several experiments is provided, and an extended bibliography is included for detailed reference.

  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. Adaptive spatially resolving detector for the extreme ultraviolet with absolute measuring capability.

    PubMed

    Benk, Markus; Bergmann, Klaus

    2009-03-01

    A spatially resolving detector for the extreme ultraviolet (XUV) and soft x-ray spectral region is presented. Principle of operation is conversion of XUV radiation to visible light by a scintillator crystal. Luminescence is detected using charge coupled device camera and imaging optics. Single layer and multilayer coatings are applied to match the system to different spectral regions of interest. Field of view and spatial resolution can be adapted to the application. Calibration of the system enables to absolutely measure in-band radiation flux on the scintillator. The setup is designed for the characterization and optimization of XUV sources and XUV optical systems. Measurements, carried out to characterize the focus in a soft x-ray microscope, are presented as an application example. PMID:19334913

  18. A new scintillating glass for high energy physics applications

    SciTech Connect

    Puseljic, D.; Baumbaugh, B.; Bishop, J.; Busenitz, J.; Cason, N.; Cunningham, J.; Gardner, R.; Kennedy, C.; Mannel, E.; Mountain, R.J.

    1987-10-01

    A new scintillating glass has been developed containing Cerium (3+) oxide in an aluminate host glass. In this material the scintillation emission spectrum is red-shifted relative to that observed for Ce/sup 3 +/ in silicate glasses. Additionally emission and absorption spectra are more widely separated in the aluminate composition, suggesting that such glasses might have improved light transmission properties. The refractive index is high, making it a potentially interesting material for use in fiber-optic tracking detectors.

  19. A new scintillating glass for high energy physics applications

    SciTech Connect

    Puseljic, D.; Baumbaugh, B.; Bishop, J.; Busenitz, J.; Cason, N.; Cunningham, J.; Gardner, R.; Kennedy, C.; Mannel, E.; Mountain, R.J.

    1988-02-01

    A new scintillating glass has been developed containing Cerium (3+) oxide in an aluminate host glass. In this material the scintillation emission spectrum is red-shifted relative to that observed for Ce/sup 3+/ in silicate glasses. Additionally, emission and absorption spectra are more widely separated in the aluminate composition, suggesting that such glasses might have improved light transmission properties. The refractive index is high, making it a potentially interesting material for use in fiber-optic tracking detectors.

  20. Investigating the energy resolution of arrays of small scintillation crystals

    Microsoft Academic Search

    D. J. Herbert; L. J. Meng; D. Ramsden

    2001-01-01

    Arrays of small scintillation crystals are being used increasingly for high-resolution imaging applications in nuclear medicine. Although the degree of pixellation now available is high for some scintillation materials, this spatial-resolution is often achieved at the expense of degraded energy-resolution due to the lower, and more variable, light-collection efficiency. The energy-resolution of a detector is, however, especially important in nuclear

  1. Lanthanum Halide Nanoparticle Scintillators for Nuclear Radiation Detection

    SciTech Connect

    Guss, P. P., Guise, R., Yuan, D., Mukhopadhyay, S., O'Brien, R., Lowe, D.

    2013-02-01

    Nanoparticles with sizes <10 nm were fabricated and characterized for their nanocomposite radiation detector properties. This work investigated the properties of several nanostructured radiation scintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum tribromide, lanthanum trifluoride, or cerium tribromide. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation.

  2. Lanthanum halide nanoparticle scintillators for nuclear radiation detection

    SciTech Connect

    Guss, Paul; Guise, Ronald [Remote Sensing Laboratory, P.O. Box 98521, M/S RSL-48, Las Vegas, Nevada 89193 (United States); Yuan Ding [National Security Technologies, LLC, Los Alamos Operations, P.O. Box 809, M/S LAO/C320, Los Alamos, New Mexico 87544 (United States); Mukhopadhyay, Sanjoy [Remote Sensing Laboratory-Andrews, Building 1783, Arnold Avenue Andrews AFB, Maryland 20762 (United States); O'Brien, Robert; Lowe, Daniel [University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154 (United States); Kang Zhitao; Menkara, Hisham [Georgia Tech Research Institute, 925 Dalney St., Atlanta, Georgia 30332 (United States); Nagarkar, Vivek V. [RMD, Inc., 44 Hunt Street, Watertown, Massachusetts 02472 (United States)

    2013-02-14

    Nanoparticles with sizes <10 nm were fabricated and characterized for their nanocomposite radiation detector properties. This work investigated the properties of several nanostructured radiation scintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum trifluoride. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation.

  3. Comparative photoluminescence study of crystalline and nanostructured scintillators

    NASA Astrophysics Data System (ADS)

    McKinney, George; McDonald, Warren; Tzolov, Marian

    2014-03-01

    Scintillators are widely used for conversion of high energy radiation/particles to visible light which can be either directly observed or further converted to electrical signal in photomultipliers or solid state detectors. We compare the light emission properties of traditional crystalline scintillators with nanostructured films created in our laboratory with the potential for use as scintillators. We have studied zinc oxide (ZnO) nanowires, zinc tungstate (ZnWO4) thin films, commercially available crystals of ZnO, ZnWO4 and commercial scintillators of yttrium aluminum garnet (YAG) and yttrium aluminum perovskite (YAP). We will present the photoluminescence emission spectra, the intensity dependence of the emission, and the photoluminescence excitation spectra. We have found that the emission spectrum of zinc oxide nanowires becomes very intense at high excitation intensities and becomes comparable with the emission from the commercial scintillators. The excitation spectra indicate the presence of subgap electronic states in the nanostructured samples and in the commercial scintillators. This study contributes to our effort of creating electron detectors for scanning electron microscopy using nanostructured scintillators.

  4. Pulsed neutron detector

    DOEpatents

    Robertson, deceased, J. Craig (late of Albuquerque, NM); Rowland, Mark S. (Livermore, CA)

    1989-03-21

    A pulsed neutron detector and system for detecting low intensity fast neutron pulses has a body of beryllium adjacent a body of hydrogenous material the latter of which acts as a beta particle detector, scintillator, and moderator. The fast neutrons (defined as having En>1.5 MeV) react in the beryllium and the hydrogenous material to produce larger numbers of slow neutrons than would be generated in the beryllium itself and which in the beryllium generate hellium-6 which decays and yields beta particles. The beta particles reach the hydrogenous material which scintillates to yield light of intensity related to the number of fast neutrons. A photomultiplier adjacent the hydrogenous material (scintillator) senses the light emission from the scintillator. Utilization means, such as a summing device, sums the pulses from the photo-multiplier for monitoring or other purposes.

  5. Scintillation of Liquid Helium for Low-Energy Nuclear Recoils

    E-print Network

    Ito, T M

    2013-01-01

    The scintillation properties of liquid helium upon the recoil of a low energy helium atom are discussed in the context of the possible use of this medium as a detector of dark matter. It is found that the prompt scintillation yield in the range of recoil energies from a few keV to 100 keV is somewhat higher than that obtained by a linear extrapolation from the measured yield for an 5 MeV alpha particle. A comparison is made of both the scintillation yield and the charge separation by an electric field for nuclear recoils and for electrons stopped in helium.

  6. Reflectance of polytetrafluoroethylene for xenon scintillation light

    NASA Astrophysics Data System (ADS)

    Silva, C.; Pinto da Cunha, J.; Pereira, A.; Chepel, V.; Lopes, M. I.; Solovov, V.; Neves, F.

    2010-03-01

    Gaseous and liquid xenon particle detectors are being used in a number of applications including dark matter search and neutrino-less double beta decay experiments. Polytetrafluoroethylene (PTFE) is often used in these detectors both as electrical insulator and as a light reflector to improve the efficiency of detection of scintillation photons. However, xenon emits in the vacuum ultraviolet (VUV) wavelength region (? ?175 nm) where the reflecting properties of PTFE are not sufficiently known. In this work, we report on measurements of PTFE reflectance, including its angular distribution, for the xenon scintillation light. Various samples of PTFE, manufactured by different processes (extruded, expanded, skived, and pressed) have been studied. The data were interpreted with a physical model comprising both specular and diffuse reflections. The reflectance obtained for these samples ranges from about 47% to 66% for VUV light. Other fluoropolymers, namely, ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), and perfluoro-alkoxyalkane (PFA) were also measured.

  7. Reflectance of polytetrafluoroethylene for xenon scintillation light

    SciTech Connect

    Silva, C.; Pinto da Cunha, J.; Pereira, A.; Chepel, V.; Lopes, M. I.; Solovov, V.; Neves, F. [Department of Physics, LIP-Coimbra, University of Coimbra, P-3004 516 Coimbra (Portugal)

    2010-03-15

    Gaseous and liquid xenon particle detectors are being used in a number of applications including dark matter search and neutrino-less double beta decay experiments. Polytetrafluoroethylene (PTFE) is often used in these detectors both as electrical insulator and as a light reflector to improve the efficiency of detection of scintillation photons. However, xenon emits in the vacuum ultraviolet (VUV) wavelength region ({lambda}{approx_equal}175 nm) where the reflecting properties of PTFE are not sufficiently known. In this work, we report on measurements of PTFE reflectance, including its angular distribution, for the xenon scintillation light. Various samples of PTFE, manufactured by different processes (extruded, expanded, skived, and pressed) have been studied. The data were interpreted with a physical model comprising both specular and diffuse reflections. The reflectance obtained for these samples ranges from about 47% to 66% for VUV light. Other fluoropolymers, namely, ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), and perfluoro-alkoxyalkane (PFA) were also measured.

  8. Neutron Scattering Facility for Characterization of CRESST and EURECA Detectors at mK Temperatures

    E-print Network

    J. -C. Lanfranchi; C. Ciemniak; C. Coppi; F. von Feilitzsch; A. Gütlein; H. Hagn; C. Isaila; J. Jochum; M. Kimmerle; S. Pfister; W. Potzel; W. Rau; S. Roth; K. Rottler; C. Sailer; S. Scholl; I. Usherov; W. Westphal

    2008-10-01

    CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) is an experiment located at the Gran Sasso underground laboratory and aimed at the direct detection of dark matter in the form of WIMPs. The setup has just completed a one year commissioning run in 2007 and is presently starting a physics run with an increased target mass. Scintillating $\\mathrm{CaWO_4}$ single crystals, operated at temperatures of a few millikelvin, are used as target to detect the tiny nuclear recoil induced by a WIMP. The powerful background identification and rejection of $\\alpha$, e$^{-}$ and $\\gamma$ events is realized via the simultaneous measurement of a phonon and a scintillation signal generated in the $\\mathrm{CaWO_4}$ crystal. However, neutrons could still be misidentified as a WIMP signature. Therefore, a detailed understanding of the individual recoil behaviour in terms of phonon generation and scintillation light emission due to scattering on Ca, O or W nuclei, respectively, is mandatory. The only setup which allows to perform such measurements at the operating temperature of the CRESST detectors has been installed at the Maier-Leibnitz-Accelerator Laboratory in Garching and is presently being commissioned. The design of this neutron scattering facility is such that it can also be used for other target materials, e.g. $\\mathrm{ZnWO_4}$, $\\mathrm{PbWO_4}$ and others as foreseen in the framework of the future multitarget tonne-scale experiment EURECA (European Underground Rare Event Calorimeter Array).

  9. Analysis of Silicon Photomultiplier Detector Waveforms from Cosmic Rays using Digital Signal Processing Techniques

    NASA Astrophysics Data System (ADS)

    Castro, Juan; Zavala, Favian; Niduaza, Rexavalmar; Wedel, Zachary; Fan, Sewan; Ritt, Stefan; Fatuzzo, Laura

    2014-03-01

    Silicon photomultiplier detectors exhibit high gain, low operating voltage, are insensitive to magnetic fields, and can detect light at the single photon level, making them very attractive for applications in fields such as particle physics, astrophysics, and medical physics. However, they exhibit effects that may prevent their optimal operation, including thermally induced high dark count rate, after pulse effects, and cross talk produced from photons in nearby pixels. In this presentation, we describe our coincidence setup using two scintillator pads and a Hamamatsu multipixel photon counter (MPPC) to gather cosmic ray produced signal pulses, and our methods of analysis for the detector waveforms. In particular, we discuss our methods of digitization, software implementation of low pass and Gaussian type filters, and the application of a domino ring sampler (DRS4) digitizing board to obtain signal waveforms to determine the operating characteristics for these detectors. Department of Education grant number P031S90007.

  10. Flexible composite radiation detector

    DOEpatents

    Cooke, D. Wayne (Santa Fe, NM); Bennett, Bryan L. (Los Alamos, NM); Muenchausen, Ross E. (Los Alamos, NM); Wrobleski, Debra A. (Los Alamos, NM); Orler, Edward B. (Los Alamos, NM)

    2006-12-05

    A flexible composite scintillator was prepared by mixing fast, bright, dense rare-earth doped powdered oxyorthosilicate (such as LSO:Ce, LSO:Sm, and GSO:Ce) scintillator with a polymer binder. The binder is transparent to the scintillator emission. The composite is seamless and can be made large and in a wide variety of shapes. Importantly, the composite can be tailored to emit light in a spectral region that matches the optimum response of photomultipliers (about 400 nanometers) or photodiodes (about 600 nanometers), which maximizes the overall detector efficiency.

  11. Nanophosphor composite scintillators comprising a polymer matrix

    DOEpatents

    Muenchausen, Ross Edward (Los Alamos, NM); Mckigney, Edward Allen (Los Alamos, NM); Gilbertson, Robert David (Los Alamos, NM)

    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.

  12. The scintillating grid illusion.

    PubMed

    Schrauf, M; Lingelbach, B; Wist, E R

    1997-04-01

    Disk-shaped luminance increments were added to the intersections of a Hermann grid consisting of medium grey bars on a black background. Illusory spots, darker than the background, were perceived as flashing within the white disks with each flick of the eye. This striking phenomenon may be referred to as the scintillating grid illusion. We determined the conditions necessary for cancelling the Hermann grid illusion, as well as the luminance requirements and the size ratio between disks and bars that elicits the scintillation effect. The fact that scanning eye movements are necessary to produce the scintillation effect sets it apart from the Hermann grid illusion. PMID:9196721

  13. Liquid Scintillator Response at Low-Energy

    NASA Astrophysics Data System (ADS)

    Passmore, Daniel

    2005-04-01

    The brightest source of neutrinos in our solar system is the sun. Neutrinos from the sun are especially hard to detect because they arrive to the Earth with energies less than 15MeV. KamLAND, a sensitive one-kiloton liquid scintillator detector allocated in a deep underground mine in central Japan, is preparing to detect solar neutrinos. To do this we must better understand the detectors response at the low energy region. Low energy particles have a different response because when traveling inside liquid scintillator at low energies they have a lower probability of emitting Cherenkov light. It is important to understand the amount of energy produced from these Cherenkov emissions and how this will affect neutrino energy reconstruction. This group has built a high precision Compton Spectrometer designed to study the response of the KamLAND liquid scintillator to the Cherenkov light. The spectrometer has high precision amplitude and time measurements by a data acquisition system based on the VME standard of electronics. The analysis of this data will be important for the future use of the KamLAND detector in detecting solar neutrinos.

  14. Radioluminescent characteristics of the EJ 299-33 plastic scintillator

    NASA Astrophysics Data System (ADS)

    Nyibule, S.; Henry, E.; Schröder, W. U.; Tõke, J.; Acosta, L.; Auditore, L.; Cardella, G.; De Filippo, E.; Francalanza, L.; Gìani, S.; Minniti, T.; Morgana, E.; Pagano, E. V.; Pirrone, S.; Politi, G.; Quattrocchi, L.; Rizzo, F.; Russotto, P.; Trifirò, A.; Trimarchi, M.

    2013-11-01

    The response of the EJ 299-33 plastic scintillator to energetic charged nuclear particles ranging from isotopes of hydrogen to isotopes of carbon has been determined over a wide energy range using a complex experimental setup and nuclear reactions induced by a 20 AMeV carbon beam on an aluminum target. A strong pulse-shape dependence of the generated light bursts on the impinging particle specie is observed, which makes this scintillator suitable, among other things, for neutron vs.?-ray identification. Fit formulas are proposed for the normalized light output as a function of particle energy for eleven isotopes of elements ranging from hydrogen to carbon.

  15. Majorana Thermosyphon Prototype Experimental Setup

    SciTech Connect

    Reid, Douglas J.; Guzman, Anthony D.; Munley, John T.

    2011-08-01

    This report presents the experimental setup of Pacific Northwest National Laboratory’s MAJORANA DEMONSTRATOR thermosyphon prototype cooling system. A nitrogen thermosyphon prototype of such a system has been built and tested at PNNL. This document presents the experimental setup of the prototype that successfully demonstrated the heat transfer performance of the system.

  16. An ideal scintillator - ZnO:Sc for sub-nanosecond pulsed radiation detection

    NASA Astrophysics Data System (ADS)

    Zhang, Kan; Ouyang, Xiaoping; Song, Zhaohui; Han, Hetong; Zuo, Yanbin; Guan, Xingyin; Tan, Xinjian; Zhang, Zichuan; Liu, Junhong

    2014-08-01

    ZnO-based scintillators are particularly well suited for use as ultrafast pulsed radiation detectors which have shown broad application prospects in various fields such as the inertial confinement fusion (ICF) diagnosis, the nuclear reaction mechanism, etc. Using the hydro-thermal method, a ZnO single-crystal doped with Scandium (ZnO:Sc) sample was prepared. As a new ZnO-based scintillator, the scintillation characteristics of ZnO:Sc have not been reported previously. In this paper, optical and scintillation characteristics of ZnO:Sc single-crystal were studied. Also a scintillation detector based on ZnO:Sc was designed. Excited by the alpha-particle, the rise time of ZnO:Sc detectors was from 162.5 to 170.7 ps, and the fall time was from 300.4 to 328.8 ps.

  17. Gamma-photon equivalent UV excitation of LYSO:Ce scintillator material

    NASA Astrophysics Data System (ADS)

    Játékos, B.; L?rincz, E.; Barócsi, A.; Erdei, G.

    2015-04-01

    In positron emission tomography (PET) slab scintillator crystals based detector modules are subject of intensive research, because all the three coordinates of the scintillation (point of interaction, POI) can be determined by them. Experimental evaluation of these detectors is done by using collimated ?-radiation where only two of the three spatial coordinates can be controlled. Alternatively, highly-detailed simulations can be used to evaluate detector performance as a function of POI, but their validation requires again experimental techniques. We propose a model validation method based on point-like, UV excitation of LYSO:Ce scintillators. The excited fluorescent pulses are identical in many respects to a scintillation excited by ?-photons. We discuss the details of our ? equivalent UV excitation arrangement, as well as compare the characteristics of the resulting fluorescence to those of scintillation light.

  18. Development of lithium-loaded liquid scintillator for PROSPECT

    NASA Astrophysics Data System (ADS)

    Norcini, Danielle; Prospect Collaboration

    2015-04-01

    The PROSPECT experiment will use a segmented detector positioned 7-20m from the High Flux Isotope Reactor core to measure the antineutrino spectrum of uranium-235 and perform a sterile neutrino search. Such measurements require the use of liquid scintillator with the capability to distinguish prompt and delayed signals from inverse beta decay events. The characterization of light yield, pulse shape discrimination performance, and neutron capture properties of the lithium-loaded scintillator have been studied with a test detector at Yale. These results will be discussed in the context of their application to antineutrino detection with the PROSPECT experiment. on behalf of the PROSPECT collaboration.

  19. InI nuclear radiation detectors

    Microsoft Academic Search

    M. R. Squillante; C. Zhou; J. Zhang; L. P. Moy; K. S. Shah

    1993-01-01

    Semiconductor radiation detectors are fabricated on single crystal wafers of indium iodide and tested both as direct radiation detectors and as optical detectors coupled to a scintillator crystal. The initial performance of the devices is encouraging but some chemical instability of the crystals is observed. Improvements in the detector performance may be possible by enhancing the InI crystal purity and

  20. Scintillation light emission studies of LSO scintillators

    SciTech Connect

    Saoudi, A.; Pepin, C.; Houde, D.; Lecomte, R.

    1999-12-01

    UV and {gamma}-ray excited luminescence and nuclear spectroscopy were used to study the relationship between the scintillation mechanisms of LSO and the spectroscopic characteristics obtained with PMT and APD readouts at room temperature. No correlation was found between scintillation decay time and light output. Like other investigators, the authors observed the existence of two distinct luminescence centers, Ce1 and Ce2, that mainly give rise to short (420 nm) and long (440 nm) emission wavelengths. The measurements showed that different LSO crystals excited by {gamma}-rays have emission spectra with largely different shapes and maxima depending on the relative population and luminescence efficiency of these centers. It was also found that the poor energy resolution of LSO and YSO scintillators is well correlated with the coexistence of the two competing luminescence mechanisms. The prevalence of either Ce1 or Ce2 luminescence tends to reduce the variance of light emission and, thus, to improve energy resolution. Inversely, the coexistence of the two centers increases variance and degrades energy resolution.

  1. 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

  2. Role of the activator in the performance of scintillators used in X-ray imaging

    Microsoft Academic Search

    I. Kandarakis; D. Cavouras

    2001-01-01

    The aim of this study was to investigate how the activator type affects the performance of X-ray scintillators. To this aim the behavior of scintillator materials was modeled under X-ray excitation conditions, similar to those used in imaging techniques. The model describes the light emission efficiency, the spectral compatibility with optical detectors (films, photodiodes, and photocathodes), and the imaging capabilities

  3. NSF/DNDO 3D Pixellated Semiconductor Scintillator Serge Luryi, PI Project Description

    E-print Network

    Luryi, Serge

    . The device is contemplated for the implementation in compound semiconductor materials, such as GaAs or InNSF/DNDO 3D Pixellated Semiconductor Scintillator Serge Luryi, PI 2007-2012 Project Description Introduction: semiconductor scintillator. There are two large groups of solid-state radiation detectors, which

  4. Operation Tumbler Snapper. Report to the Test Director. Test of scintillator optical-path technique

    Microsoft Academic Search

    1985-01-01

    Experiments were conducted to determine the feasibility of a technique employing scintillators near the device in conjunction with remote photosensitive detectors for measurements of reaction history to be conducted on Mike Shot of Operation Ivy, and to determine the maximum gamma-ray intensity and total dosage at which scintillators could be employed. The principal objectives of these tests were to:; (1)

  5. Scintillator Development for the PROSPECT Experiment

    NASA Astrophysics Data System (ADS)

    Yeh, Minfang

    2014-03-01

    Doped scintillator is the target material of choice for antineutrino detection as it utilizes the time-delayed coincidence signature of the positron annihilation and neutron capture resulting from the Inverse Beta Decay (IBD) interaction. Additionally, the multiple gamma rays or heavy ions emitted after neutron capture on either Gd or 6Li respectively provide a distinct signal for the identification of antineutrino events and therefore significantly enhance accidental background reduction. The choice of scintillator and dopant depends on the detector requirements and scintillator performance criteria. Both Gd and 6Li doped scintillators have been used in past reactor antineutrino experiments such as Double Chooz, Daya Bay, RENO, and Bugey3 and are currently under investigation by the PROSPECT collaboration. Their properties in terms of light yield, optical transparency, chemical stability and background rejection efficiency using Pulse Shape Discrimination (PSD) will be reported. Research sponsored by the U.S. Department of Energy, Office of Nuclear Physics and Office of High Energy Physics, under contract with Brookhaven National Laboratory-Brookhaven Science Associates.

  6. Status of Tests of Cryogenic Scintillators with a 2.8 K Optical Cryostat

    NASA Astrophysics Data System (ADS)

    Verdier, M.-A.; Augier, C.; Coron, N.; De Jésus, M.; de Marcillac, P.; Di Stefano, P. C. F.; Dujardin, C.; Gascon, J.; Gironnet, J.; Juillard, A.; Loaiza, P.; Sanglard, V.; Scorza, S.; Torres, L.; Vanzetto, S.

    2009-12-01

    In order to increase the range of targets for rare events detection at low temperature such as dark matter or neutrinoless double beta decay events, we have developed an optical cryostat to study the scintillation of crystals down to 2.8 K under ? particles, thanks to its compact optical geometry. Some scintillation properties of BGO (Bi4Ge3O12) at low temperature obtained with this setup will be shown here.

  7. Cathodoluminescence studies of commercial and nano-structured scintillators

    NASA Astrophysics Data System (ADS)

    McDoanld, Warren; McKinney, George; Tzolov, Marian

    2014-03-01

    Scintillators have applications in fundamental research and in consumer products, e.g. detectors, scanners, and televisions. This research focused on analyzing the cathodoluminescence of different single-crystal scintillators with an originally developed method for evaluation of their performance, which allows for a direct comparison of different scintillators. We have studied yttrium aluminum garnet (YAG), yttrium aluminum perovskite (YAP) scintillators, zinc oxide single crystal, zinc tungstate single crystal, zinc oxide nanowires, and zinc tungstate film. The commercial scintillators are covered with conductive film which prevents low energy electrons from effectively interacting with the scintillator. We have varied the voltage accelerating the electrons with the intention of finding the threshold below which this effect will impact the performance of the scintillators. The same procedure was followed for the nanowires and zinc tungstate film which have enough conductivity and don't require a top conducting film. The threshold was established to be around 3 kV for the YAG and there is no threshold for the films, which perform much better at these low voltages. This property of the films has the potential for application in desktop scanning electron microscopes, where the accelerating voltage is low. The voltage dependence of the cathodoluminescence intensity follows an exponential trend and we present a model explaining it.

  8. CaF2(Eu): an ``old'' scintillator revisited

    NASA Astrophysics Data System (ADS)

    Plettner, C.; Pausch, G.; Scherwinski, F.; Herbach, C. M.; Lentering, R.; Kong, Y.; Römer, K.; Grodzicka, M.; Szcze?niak, T.; Iwanowska, J.; Moszy?ski, M.

    2013-06-01

    Homeland security applications demand performant two-plane Compton-camera systems, with high detector efficiency, good nuclide identification and able to perform in-field conditions. A low-Z scintillator has been proposed and studied as a promising candidate for use in the scattering plane of a scintillator-based Compton camera: CaF2(Eu) [1]. All the relevant properties for the application of this scintillator in a mobile Compton camera system, have been addressed: the energy resolution and the non-proportionality at room temperature and in the temperature range of -20°C to +55°C, the photoelectron yield and the relative light yield in the relevant temperature range. A new method of inferring the relative light output of scintillators has been proposed.

  9. A Scintillator Purification Plant and Fluid Handling System for SNO+

    E-print Network

    Ford, Richard J

    2015-01-01

    A large capacity purification plant and fluid handling system has been constructed for the SNO+ neutrino and double-beta decay experiment, located 6800 feet underground at SNOLAB, Canada. SNO+ is a refurbishment of the SNO detector to fill the acrylic vessel with liquid scintillator based on Linear Alkylbenzene (LAB) and 2 g/L PPO, and also has a phase to load natural tellurium into the scintillator for a double-beta decay experiment with 130Te. The plant includes processes multi-stage dual-stream distillation, column water extraction, steam stripping, and functionalized silica gel adsorption columns. The plant also includes systems for preparing the scintillator with PPO and metal-loading the scintillator for double-beta decay exposure. We review the basis of design, the purification principles, specifications for the plant, and the construction and installations. The construction and commissioning status is updated.

  10. A Scintillator Purification Plant and Fluid Handling System for SNO+

    E-print Network

    Richard J. Ford; for the SNO+ Collaboration

    2015-06-29

    A large capacity purification plant and fluid handling system has been constructed for the SNO+ neutrino and double-beta decay experiment, located 6800 feet underground at SNOLAB, Canada. SNO+ is a refurbishment of the SNO detector to fill the acrylic vessel with liquid scintillator based on Linear Alkylbenzene (LAB) and 2 g/L PPO, and also has a phase to load natural tellurium into the scintillator for a double-beta decay experiment with 130Te. The plant includes processes multi-stage dual-stream distillation, column water extraction, steam stripping, and functionalized silica gel adsorption columns. The plant also includes systems for preparing the scintillator with PPO and metal-loading the scintillator for double-beta decay exposure. We review the basis of design, the purification principles, specifications for the plant, and the construction and installations. The construction and commissioning status is updated.

  11. Efficiency of Scintillator Materials in the Energy Range 8.0-32.0 keV

    SciTech Connect

    Kinney, J H; Haupt, D L

    2002-07-01

    X-ray microtomography requires the measurement of x-ray attenuation along ray paths through a specimen, and on the inversion of these data to obtain a spatially resolved mapping of the microstructure of the specimen. To do this efficiently, two-dimensional array detectors are often used to measure the transmitted x-rays by capturing and recording each x-ray incident on the detector. The highest resolution CT instruments perform this by converting the incident x-rays to visible light, and then focusing this light onto a charge-coupled-device (CCD) detector. The light output of the scintillator (photons per incident x-ray), the numerical aperture of the optical lens system, and the quantum efficiency of the CCD govern the efficiency of the detection process. Several years earlier, our group performed an investigation aimed at determining the best scintillator material for high-resolution synchrotron CT. The selection criteria included light output in the 8-32 keV energy range, the spatial resolution of the scintillator, the wavelength of the scintillation radiation, and the stability and ease of polishing of the scintillator. A list of the scintillators that we considered, with the exceptions of the more recently developed glass scintillators, is provided in Table 1. Among these scintillators, we concluded that single crystal cadmium tungstate was optimum; we have used this material in all subsequent synchrotron CT systems. Since this original study, several doped-glass scintillators have become available. The LSO (Lu orthosilicates) scintillators, developed for PET scanning, show considerable light output at high energy (energies above 500 keV). Theoretically, the light output of these scintillators should be twice that of the cadmium tungstate. The purpose of this study was to determine the efficiency of two such scintillators (LSO:Yt and IQI-401 high density terbium activated glass) in the energy range from 8-32 keV.

  12. First results on light readout from the 1-ton ArDM liquid argon detector for dark matter searches

    NASA Astrophysics Data System (ADS)

    ArDM Collaboration; Amsler, C.; Badertscher, A.; Boccone, V.; Bueno, A.; Carmona-Benitez, M. C.; Creus, W.; Curioni, A.; Daniel, M.; Dawe, E. J.; Degunda, U.; Gendotti, A.; Epprecht, L.; Horikawa, S.; Kaufmann, L.; Knecht, L.; Laffranchi, M.; Lazzaro, C.; Lightfoot, P. K.; Lussi, D.; Lozano, J.; Marchionni, A.; Mavrokoridis, K.; Melgarejo, A.; Mijakowski, P.; Natterer, G.; Navas-Concha, S.; Otyugova, P.; de Prado, M.; Przewlocki, P.; Regenfus, C.; Resnati, F.; Robinson, M.; Rochet, J.; Romero, L.; Rondio, E.; Rubbia, A.; Scotto-Lavina, L.; Spooner, N. J. C.; Strauss, T.; Ulbricht, J.; Viant, T.

    2010-11-01

    ArDM-1t is the prototype for a next generation WIMP detector measuring both the scintillation light and the ionization charge from nuclear recoils in a 1-ton liquid argon target. The goal is to reach a minimum recoil energy of 30 keVr to detect recoiling nuclei. In this paper we describe the experimental concept and present results on the light detection system, tested for the first time in ArDM on the surface at CERN. With a preliminary and incomplete set of PMTs, the light yield at zero electric field is found to be between 0.3-0.5 phe/keVee depending on the position within the detector volume, confirming our expectations based on smaller detector setups.

  13. Silicon as an Unconventional Detector in Positron Emission Tomography

    PubMed Central

    Clinthorne, N.H.; Brzezinski, K.; Chesi, E.; Cochran, E.; Grkovski, M.; Groši?ar, B.; Honscheid, K.; Huh, S.; Kagan, H.; Lacasta, C.; Linhart, V.; Mikuž, M.; Smith, S.; Stankova, V.; Studen, A.; Weilhammer, P.; žontar, D.

    2012-01-01

    Positron emission tomography (PET) is a widely used technique in medical imaging and in studying small animal models of human disease. In the conventional approach, the 511 keV annihilation photons emitted from a patient or small animal are detected by a ring of scintillators such as LYSO read out by arrays of photodetectors. Although this has been a successful in achieving ~5mm FWHM spatial resolution in human studies and ~1mm resolution in dedicated small animal instruments, there is interest in significantly improving these figures. Silicon, although its stopping power is modest for 511 keV photons, offers a number of potential advantages over more conventional approaches. Foremost is its high spatial resolution in 3D: our past studies show that there is little diffculty in localizing 511 keV photon interactions to ~0.3mm. Since spatial resolution and reconstructed image noise trade off in a highly non-linear manner that depends on the PET instrument response, if high spatial resolution is the goal, silicon may outperform standard PET detectors even though it has lower sensitivity to 511 keV photons. To evaluate silicon in a variety of PET “magnifying glass” configurations, an instrument has been constructed that consists of an outer partial-ring of PET scintillation detectors into which various arrangements of silicon detectors can be inserted to emulate dual-ring or imaging probe geometries. Recent results have demonstrated 0.7 mm FWHM resolution using pad detectors having 16×32 arrays of 1.4mm square pads and setups have shown promising results in both small animal and PET imaging probe configurations. Although many challenges remain, silicon has potential to become the PET detector of choice when spatial resolution is the primary consideration. PMID:23230345

  14. Comparison of Lithium Gadolinium Borate Crystal Shards in Scintillating and Nonscintillating Plastic Matrices

    Microsoft Academic Search

    Kareem Kazkaz; Nathaniel S. Bowden; Marisa Pedretti

    2011-01-01

    We present a method for detecting neutrons using scintillating lithium gadolinium borate crystal shards in a plastic matrix while maintaining high gamma rejection. We have procured two cylindrical detectors, 5\\

  15. Detecting sub-MeV neutrons in solid plastic scintillator with gamma-ray discrimination

    E-print Network

    Kovash, Michael A.

    We report on recent efforts to design a solid plastic scintillation hodoscope to measure neutron production cross sections at low energies. Our program includes not only the development of the detector itself, but also a ...

  16. Particle detector spatial resolution

    DOEpatents

    Perez-Mendez, V.

    1992-12-15

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs.

  17. Particle detector spatial resolution

    DOEpatents

    Perez-Mendez, Victor (Berkeley, CA)

    1992-01-01

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector.

  18. Atmospheric Scintillation in Astronomical Photometry

    E-print Network

    Osborn, J; Dhillon, V S; Wilson, R W

    2015-01-01

    Scintillation noise due to the Earth's turbulent atmosphere can be a dominant noise source in high-precision astronomical photometry when observing bright targets from the ground. Here we describe the phenomenon of scintillation from its physical origins to its effect on photometry. We show that Young's (1967) scintillation-noise approximation used by many astronomers tends to underestimate the median scintillation noise at several major observatories around the world. We show that using median atmospheric optical turbulence profiles, which are now available for most sites, provides a better estimate of the expected scintillation noise and that real-time turbulence profiles can be used to precisely characterise the scintillation noise component of contemporaneous photometric measurements. This will enable a better understanding and calibration of photometric noise sources and the effectiveness of scintillation correction techniques. We also provide new equations for calculating scintillation noise, including ...

  19. Scintillating bolometers for fast neutron spectroscopy in rare events searches

    NASA Astrophysics Data System (ADS)

    Martínez, M.; Coron, N.; Ginestra, C.; Gironnet, J.; Gressier, V.; Leblanc, J.; de Marcillac, P.; Redon, T.; Di Stefano, P.; Torres, L.; Veber, P.; Velazquez, M.; Viraphong, O.

    2012-07-01

    Neutrons are a relevant background in rare events physics. Detectors based on fast neutron-induced nuclear reactions are commonly used for fast neutron spectroscopy. In this subject, scintillating bolometers provide an excellent energy resolution and particle discrimination by the simultaneous measurement of the heat and emitted light. Our group has constructed several 6Li and 10B based massive scintillating bolometers (LiF, Li6Eu(BO3)3, Li6Gd(BO3)3), with energy resolutions ranging from 16 to 200 keV. First results of a 32 gr 6LiF scintillating bolometer enriched at 95% in 6Li operated at 20 mK are presented. The use of this material in a multi-target cryogenic dark matter experiment, like EURECA, would allow monitoring the incident neutron flux in the detector during the data-taking.

  20. Surface preparation and coupling in plastic scintillator dosimetry

    SciTech Connect

    Ayotte, Guylaine; Archambault, Louis; Gingras, Luc; Lacroix, Frederic; Beddar, A. Sam; Beaulieu, Luc [Departement de physique, de genie physique et d'optique, Universite Laval, Quebec City, Quebec, G1K7P4 (Canada) and Departement de Radio-Oncologie, Hotel Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec City, Quebec, G1R2J6 (Canada); Departement de physique, de genie physique et d'optique, Universite Laval, Quebec City, Quebec, G1K7P4 (Canada) and Department de Radio-Oncologie, Hotel Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec City, Quebec, G1R2J6 (Canada) and Department of Radiation Physics, Division of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department de physique, de genie physique et d'optique, Universite Laval, Quebec City, Quebec, G1K7P4 (Canada) and Department de Radio-Oncologie, Hotel Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec City, Quebec, G1R2J6 (Canada); Department of Radiation Physics, Division of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department de physique, de genie physique et d'optique, Universite Laval, Quebec City, Quebec, G1K7P4 (Canada) and Department de Radio-Oncologie, Hotel Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec City, Quebec, G1R2J6 (Canada)

    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.

  1. The Oriented Scintillation Spectrometer Experiment - Instrument description

    NASA Astrophysics Data System (ADS)

    Johnson, W. N.; Kinzer, R. L.; Kurfess, J. D.; Strickman, M. S.; Purcell, W. R.; Grabelsky, D. A.; Ulmer, M. P.; Hillis, D. A.; Jung, G. V.; Cameron, R. A.

    1993-06-01

    The Oriented Scintillation Spectrometer Experiment on the Arthur Holly Compton Gamma Ray Observatory satellite uses four actively shielded NaI (Tl)-CsI(Na) phoswich detectors to provide gamma-ray line and continuum detection capability in the 0.05-10 MeV energy range. The instrument includes secondary capabilities for gamma-ray and neutron detection between 10 and 250 MeV. The detectors have 3.8 deg x 11.04 deg (FWHM) fields of view defined by tungsten collimators. Each detector has an independent, single-axis orientation system which permits offset pointing from the spacecraft Z-axis for background measurements and multitarget observations. The instrument, and its calibration and performance, are described.

  2. The Oriented Scintillation Spectrometer Experiment - Instrument description

    NASA Technical Reports Server (NTRS)

    Johnson, W. N.; Kinzer, R. L.; Kurfess, J. D.; Strickman, M. S.; Purcell, W. R.; Grabelsky, D. A.; Ulmer, M. P.; Hillis, D. A.; Jung, G. V.; Cameron, R. A.

    1993-01-01

    The Oriented Scintillation Spectrometer Experiment on the Arthur Holly Compton Gamma Ray Observatory satellite uses four actively shielded NaI (Tl)-CsI(Na) phoswich detectors to provide gamma-ray line and continuum detection capability in the 0.05-10 MeV energy range. The instrument includes secondary capabilities for gamma-ray and neutron detection between 10 and 250 MeV. The detectors have 3.8 deg x 11.04 deg (FWHM) fields of view defined by tungsten collimators. Each detector has an independent, single-axis orientation system which permits offset pointing from the spacecraft Z-axis for background measurements and multitarget observations. The instrument, and its calibration and performance, are described.

  3. LC-DET-2006-009 CALICE scintillator HCAL commissioning

    E-print Network

    ; to develop a calibration procedure applicable to the 8000 SiPM used to read out the AHCAL; and to testLC-DET-2006-009 CALICE scintillator HCAL commissioning experience and test beam program Nicola D suited detector component to measure their four-momentum. The goal is to reach a jet energy resolution

  4. Development of nanocomposite scintillators R. E. Del Sesto

    E-print Network

    to more efficient and precise radiographical imaging methods. Modern- day x-ray or radiation detectors- tion of nuclear materials. In order to create a new class of scintillator materials that combines good nano- composites exhibit a photopeak when exposed to 137 Cs source -radiation. Background Radiation

  5. 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.

  6. Collection of scintillation light from small BGO crystals

    Microsoft Academic Search

    Simon R. Cherry; Yiping Shao; Martin P. Tornai; Stefan Siegel; Anthony R. Ricci; Michael E. Phelps

    1995-01-01

    We propose to develop a high resolution positron emission tomography (PET) detector designed for animal imaging. The detector consists of a 2-D array of small bismuth germanate (BGO) crystals coupled via optical fibers to a multi-channel photomultiplier tube (MC-PMT). Though this approach offers several advantages over the conventional BGO block design, it does require that a sufficient number of scintillation

  7. Energy Calibration of Double Chooz Detector

    NASA Astrophysics Data System (ADS)

    Yang, Guang

    2013-04-01

    Reactor anti-neutrino oscillation experiment Double Chooz was designed to measure the mixing angle theta-13 with unprecedented sensitivity. The Double Chooz detector system consists of a main detector, an outer veto system and several calibration systems. The main detector has a cylindrical structure. It consists of the target vessel, a liquid scintillator loaded with Gd, surrounded by the gamma-catcher, a non-loaded liquid scintillator. A buffer region of non-scintillating liquid surrounds the gamma-catcher and serves to host 390 photomultiplier tubes and to decrease the level of accidental background. The Inner Veto region is outside the buffer, and the Outer Veto system covers all detector components. Far detector is operational and the near detector is under construction. The detector is calibrated with light sources, radioactive point sources, cosmics and natural radioactivity. In this presentation we will describe use of radioactive calibration sources and cross-checks performed with cosmics and natural radioactivity.

  8. Modern detectors for radiation monitors

    Microsoft Academic Search

    A. V. Shumakov; A. S. Sviridov; S. V. Kolesnikov

    2011-01-01

    The possibilities of using modern photon and neutron detectors for developing radiation monitors, specifically, LaBr3, Bi4Ge3O12, CdWO4, LiI, ZnO, Lu2SiO5(Ce), CdTe, and HgI2, microtubes from organic scintillators, nanomaterials, and detectors based on gaseous and solid-state electronic multipliers\\u000a are examined. A comparison is made of conventional detectors based on NaI(Tl) and CsI(Tl), plastic scintillators, and 3He counters. The advantages of the

  9. Status and Prospects of the HERMES Recoil Detector

    E-print Network

    /Scintillator sandwich Fiber Detector (SFT) 2 barrels with 4 layers of scintillating fibers 2 parallel and 2 stereo SFT Particle Identification 8HERMES Recoil Detector A. Mussgiller, SPIN 2008, 10/10/08 SSDV /c : SSD & SFT & PDp ~0.6 GeV /c #12; Particle Identification (p > 0

  10. Radiation detector signal processing using sampling kernels without bandlimiting constraints

    Microsoft Academic Search

    Jürgen Stein; Marcus J. Neuer; Claus-Michael Herbach; Guntram Pausch; Kai Ruhnau

    2007-01-01

    For the development of digital signal processing systems for fast scintillation detectors we comprehensively study the modeling of nuclear signals, deconvolution of detector pulses and signal sampling. Applications for new scintillators with light decay times of a few nanoseconds demand suitable low power digital systems running at lowest possible sampling rates. We are interested in accurate sub-nanosecond timing and optimal

  11. Forward and central preshower detectors for the D0 upgrade

    NASA Astrophysics Data System (ADS)

    Del Signore, Ken

    1998-11-01

    Within the upgraded D0 detector at Fermi National Accelerator Laboratory, forward and central preshower detectors will be used for fast level 1 triggering of electrons. These detectors consist of approximately 25000 channels of extruded scintillator strips with embedded wave length shifter fiber readout. Readout is via clear fiber lightguide to Visible Light Photon Counters. An overview of each system will be presented. Results of prototype detectors to cosmic rays will be presented. Scintillator/fiber manufacture and assembly will be discussed.

  12. 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.

  13. Boron loaded scintillator

    DOEpatents

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

  14. 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.

  15. The Scintillating Grid Illusion

    Microsoft Academic Search

    MICHAEL SCHRAUF; BERND LINGELBACH; EUGENE R WIST

    1997-01-01

    Disk-shaped luminance increments were added to the intersections of a Hermann grid consisting of medium grey bars on a black background. Illusory spots, darker than the background, were perceived as flashing within the white disks with each flick of the eye. This striking phenomenon may be referred to as the scintillating grid illusion. We determined the conditions necessary for cancelling

  16. Understanding the SNO+ Detector

    NASA Astrophysics Data System (ADS)

    Kamdin, K.

    SNO+, a large liquid scintillator experiment, is the successor of the Sudbury Neutrino Observatory (SNO) experiment. The scintillator volume will be loaded with large quantities of 130Te, an isotope that undergoes double beta decay, in order to search for neutrinoless double beta decay. In addition to this search, SNO+ has a broad physics program due to its sensitivity to solar and supernova neutrinos, as well as reactor and geo anti-neutrinos. SNO+ can also place competitive limits on certain modes of invisible nucleon decay during its first phase. The detector is currently undergoing commissioning in preparation for its first phase, in which the detector is filled with ultra pure water. This will be followed by a pure scintillator phase, and then a Tellurium-loaded scintillator phase to search for neutrinoless double beta decay. Here we present the work done to model detector aging, which was first observed during SNO. The aging was found to reduce the optical response of the detector. We also describe early results from electronics calibration of SNO+.

  17. Characterization of cerium fluoride nanocomposite scintillators

    SciTech Connect

    Stange, Sy [Los Alamos National Laboratory; Esch, Ernst I [Los Alamos National Laboratory; Brown, Leif O [Los Alamos National Laboratory; Couture, Aaron J [Los Alamos National Laboratory; Mckigney, Edward A [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Del Sesto, Rico E [Los Alamos National Laboratory; Gilbertson, Robert D [Los Alamos National Laboratory; Mccleskey, T Mark [Los Alamos National Laboratory; Reifarth, Rene [Los Alamos National Laboratory

    2009-01-01

    Measurement of the neutron capture cross-sections of a number of short-lived isotopes would advance both pure and applied scientific research. These cross-sections are needed for calculation of criticality and waste production estimates for the Advanced Fuel Cycle Initiative, for analysis of data from nuclear weapons tests, and to improve understanding of nucleosynthesis. However, measurement of these cross-sections would require a detector with a faster signal decay time than those used in existing neutron capture experiments. Crystals of faster detector materials are not available in sufficient sizes and quantities to supply these large-scale experiments. Instead, we propose to use nanocomposite detectors, consisting of nanoscale particles of a scintillating material dispersed in a matrix material. We have successfully fabricated cerium fluoride (CeF{sub 3}) nanoparticles and dispersed them in a liquid matrix. We have characterized this scintillator and have measured its response to neutron capture. Results of the optical, structural, and radiation characterization will be presented.

  18. A novel epitaxially grown LSO-based thin-film scintillator for micro-imaging using hard synchrotron radiation.

    PubMed

    Douissard, Paul Antoine; Cecilia, Angelica; Martin, Thierry; Chevalier, Valentin; Couchaud, Maurice; Baumbach, Tilo; Dupré, Klaus; Kühbacher, Markus; Rack, Alexander

    2010-09-01

    The efficiency of high-resolution pixel detectors for hard X-rays is nowadays one of the major criteria which drives the feasibility of imaging experiments and in general the performance of an experimental station for synchrotron-based microtomography and radiography. Here the luminescent screen used for the indirect detection is focused on in order to increase the detective quantum efficiency: a novel scintillator based on doped Lu(2)SiO(5) (LSO), epitaxially grown as thin film via the liquid phase epitaxy technique. It is shown that, by using adapted growth and doping parameters as well as a dedicated substrate, the scintillation behaviour of a LSO-based thin crystal together with the high stopping power of the material allows for high-performance indirect X-ray detection. In detail, the conversion efficiency, the radioluminescence spectra, the optical absorption spectra under UV/visible-light and the afterglow are investigated. A set-up to study the effect of the thin-film scintillator's temperature on its conversion efficiency is described as well. It delivers knowledge which is important when working with higher photon flux densities and the corresponding high heat load on the material. Additionally, X-ray imaging systems based on different diffraction-limited visible-light optics and CCD cameras using among others LSO-based thin film are compared. Finally, the performance of the LSO thin film is illustrated by imaging a honey bee leg, demonstrating the value of efficient high-resolution computed tomography for life sciences. PMID:20724778

  19. Measurement of ortho-positronium properties in liquid scintillators

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    Pulse shape discrimination is a well-established technique for background rejection in liquid scintillator detectors. It is particularly effective in separating heavy particles from light particles, but not in distinguishing electrons from positrons. This inefficiency can be overtaken by exploiting the formation of ortho-positronium (o-Ps), which alters the time profile of light pulses induced by positrons. We characterized the o-Ps properties in the most commonly used liquid scintillators, i.e. PC, PXE, LAB, OIL and PC + PPO. In addition, we studied the effects of scintillator doping on the o-Ps properties for dopants used in neutrino-less double beta decay experiments (Nd and Te) and in anti-neutrino and neutron detection (Gd and Li respectively). We found that the o-Ps properties are similar in all the tested scintillators, with a lifetime around 3 ns and a formation probability of about 50%. This result indicates that an o-Ps-enhanced pulse shape discrimination can be applied in liquid scintillator detectors for neutrino and anti-neutrino detection and for neutrino-less double beta decay search.

  20. Radiation effects on the resolution (MTF) of the scintillator coupled CMOS APS array imager for non-destructive test X-ray imaging

    Microsoft Academic Search

    Kwang Huyn Kim; Gyuseong Cho

    2004-01-01

    In this paper, the effects of the transmitted X-ray through the scintillator on the resolution in the scintillator coupled CMOS APS array imager were investigated using a modulation transfer function (MTF). By measuring the system MTF of the detector at each cumulative exposure, we found out that the resolution of the detector was not permanent but changed with the amount

  1. Setups

    Microsoft Academic Search

    Jean-Philippe Platteau; Petros G. Sekeris

    This paper aims at a better understanding of the conditions under which unequal rank or power positions may get permanently established through asymmetric gift exchange when a gift brings pride to the donor and shame to the recipient. The central result obtained is that an asymmetric gift exchange equilibrium can occur only if the importance attached to social shame by

  2. Scintillating bolometers for Double Beta Decay search

    E-print Network

    Luca Gironi

    2009-11-05

    In the field of Double Beta Decay (DBD) searches, the use of high resolution detectors in which background can be actively discriminated is very appealing. Scintillating bolometers containing a Double Beta Decay emitter can largely fulfill this very interesting possibility. In this paper we present the latest results obtained with CdWO4 and CaMoO4 crystals. Moreover we report, for the first time, a very interesting feature of CaMoO4 bolometers: the possibility to discriminate beta-gamma events from those induced by alpha particles thanks to different thermal pulse shape.

  3. 8. Particle detectors 8.1 Emulsions

    E-print Network

    Pohl, Martin Karl Wilhelm

    8. Particle detectors 8.1 Emulsions Nuclear emulsions can be used to give 3-dimensional information-altitude balloons. A second way of measuring energetic charged particles involves scintillation detectors. Here of the detectors is low, so they are not ideal at particle energies below about 100 keV, but they are simple

  4. The weighting function for scintillation on a folded path

    NASA Astrophysics Data System (ADS)

    An, B. G.

    1984-12-01

    In the case of a spherical beam wave propagating in a weakly inhomogeneous medium which has a Kolmogorov spectrum, Dr. Ze'evi derived a weighting function for scintillation for a direct and for a folded path with respect to the position of the turbulent medium. Experiments were performed to verify Ze'evi's weighting function for a folded path for three different types of reflectors. The experimental results did not support Dr. Ze'evi's theory. We found that the scintillation weighting functions are less weighted near the detector and have an unexpected increase near the reflector. These results are discussed by using a geometric optical model of the turbulence.

  5. The Scintillating Optical Fiber Calorimeter Instrument Performance (SOFCAL)

    NASA Technical Reports Server (NTRS)

    Christl, M. J.; Benson, C. M.; Berry, F. A.; Fountain, W. F.; Gregory, J. C.; Johnson, J. S.; Munroe, R. B.; Parnell, T. A.; Takahashi, Y.; Watts, J. W.

    1999-01-01

    SOFCAL is a balloon-borne instrument designed to measure the P-He cosmic ray spectra from about 200 GeV/amu - 20 TeV/amu. SOFCAL uses a thin lead and scintillating-fiber ionization calorimeter to measure the cascades produced by cosmic rays interacting in the hybrid detector system. Above the fiber calorimeter is an emulsion chamber that provides the interaction target, primary particle identification and in-flight energy calibration for the scintillating fiber data. The energy measurement technique and its calibration are described, and the present results from the analysis of a 1 day balloon flight will be presented.

  6. Polystyrene-based scintillator with pulse-shape discrimination capability

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    Polystyrene-based scintillators with 2-phenyl-5-(4-tert-butylephenyl)-1,3,4-oxadiazole (tert-BuPPD) or 2,5-di-(3-methylphenyl)-1,3,4 oxadiazole (m-DMePPD) are proposed for pulse-shape n/?-discrimination. These scintillators have improved mechanical properties, long operational time and high n/? discrimination parameter - figure of merit (1.49 and 1.81 in a wide energy region), so they can be used as detectors of fast neutrons in the presence of gamma radiation background.

  7. Composite scintillator screen

    DOEpatents

    Zeman, Herbert D. (1687 Peach St., Memphis, TN 38112)

    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.

  8. Scintillator spent fuel monitor

    SciTech Connect

    Moss, C.E.; Nixon, K.V.; Bernard, W.

    1980-01-01

    A monitor for rapidly measuring the gross gamma-ray flux immediately above spent fuel assemblies in underwater storage racks has been developed. It consists of a plastic scintillator, photomultiplier, collimator, and a small battery-powered electronics package. The crosstalk from an isolated fuel assembly to an adjacent void is only about 2%. The mean difference between the measured gamma-ray flux and the flux estimated from the declared burnup and cooling time with a simple formula is 22%.

  9. Pulse-shape discrimination of scintillation from alpha and beta particles with liquid scintillator and Geiger-mode multipixel avalanche diodes

    Microsoft Academic Search

    I. Kreslo; I. Badhrees; S. Delaquis; A. Ereditato; S. Janos; M. Messina; U. Moser; B. Rossi; M. Zeller

    2011-01-01

    A successfull application of Geiger-mode multipixel avalanche diodes (GMAPDs) for pulse-shape discrimination in alpha-beta spectrometry using organic liquid scintillator is described in this paper. Efficient discrimination of alpha and beta components in the emission of radioactive isotopes is achieved for alpha energies above 0.3 MeV. The ultra-compact design of the scintillating detector helps to efficiently suppress cosmic-ray and ambient radiation

  10. Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

    PubMed Central

    Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G.; Nagarkar, Vivek V.

    2011-01-01

    Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional “straight-cut” (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors. PMID:21731108

  11. Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera.

    PubMed

    Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G; Nagarkar, Vivek V

    2011-06-01

    Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional "straight-cut" (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors. PMID:21731108

  12. Introducing Third-Year Undergraduates to GEANT4 Simulations of Light Transport and Collection in Scintillation Materials

    ERIC Educational Resources Information Center

    Riggi, Simone; La Rocca, Paola; Riggi, Francesco

    2011-01-01

    GEANT4 simulations of the processes affecting the transport and collection of optical photons generated inside a scintillation detector were carried out, with the aim to complement the educational material offered by textbooks to third-year physics undergraduates. Two typical situations were considered: a long scintillator strip with and without a…

  13. Studying the energy dependence of intrinsic conversion efficiency of single crystal scintillators under X-ray excitation

    NASA Astrophysics Data System (ADS)

    Kalyvas, N.; Valais, I.; David, S.; Michail, Ch.; Fountos, G.; Liaparinos, P.; Kandarakis, I.

    2014-05-01

    Single crystal scintilators are used in various radiation detectors applications. The efficiency of the crystal can be determined by the Detector Optical Gain (DOG) defined as the ratio of the emitted optical photon flux over the incident radiation photons flux. A parameter affecting DOG is the intrinsic conversion efficiency ( n C ) giving the percentage of the X-ray photon power converted to optical photon power. n C is considered a constant value for X-ray energies in the order of keV although a non-proportional behavior has been reported. In this work an analytical model, has been utilized to single crystals scintillators GSO:Ce, LSO:Ce and LYSO:Ce to examine whether the intrinsic conversion efficiency shows non proportional behavior under X-ray excitation. DOG was theoretically calculated as a function of the incident X-ray spectrum, the X-ray absorption efficiency, the energy of the produced optical photons and the light transmission efficiency. The theoretical DOG values were compared with experimental data obtained by irradiating the crystals with X-rays at tube voltages from 50 to 140 kV and by measuring the light energy flux emitted from the irradiated screen. An initial value for n C (calculated from literature data) was assumed for the X-ray tube voltage of 50 kV. For higher X-ray tube voltages the optical photon propagation phenomena was assumed constant and any deviations between experimental and theoretical data were associated with changes in the intrinsic conversion efficiency. The experimental errors were below 7% for each experimental setup. The behavior of n C values for LSO:Ce and LYSO:Ce were found very similar, i.e., ranging with values from 0.089 at 50 kV to 0.015 at 140 kV, while for GSO:Ce, n C demonstrated a peak at 80 kV.

  14. The LHCb Upgrade Scintillating Fibre Tracker

    E-print Network

    Leverington, Blake D

    2014-01-01

    The Scintillating Fibre (SciFi) Tracker is designed to replace the current downstream tracking detectors in the LHCb Upgrade during 2018 (CERN/LHCC 2014-001; LHCb TDR 15). The operation and the results obtained from the data collected 2011 and 2012 demonstrate that the current detector is robust and functioning very well. However, the limit of O ( 1 fb-1) of data per year cannot be overcome without improving the detector. This will be achieved using 25 ns bunch spacing with the average number of proton-proton interactions per bunch crossing n = 7 : 6. Collecting data at this luminosity will only be possible if the detector is improved by increasing the readout of the front-end electronics to 40MHz and implementing a more flexible software-based triggering system that will increase the data rate as well as the efficiency. The increase in interactions per bunch crossing will result in an increased occupancy in the tracking detectors and will exceed the operational occupancy for the Outer Tracker. Here we presen...

  15. Characterization of flash gamma-ray detectors that operate in the Trad\\/s range

    Microsoft Academic Search

    T. W. L. Sanford; J. A. Halbleib; R. C. Mock; D. E. Beutler; G. A. Carlson; J. W. Poukey

    1990-01-01

    Compton-diode detectors, scintillator-photodiode detectors, and Cherenkov-photodiode detectors, designed to measure the intense pulsed bremsstrahlung field of HERMES III, are described and characterized in the field of HERMES III. Measurements and modeling show that (1) the Compton-diode detector measures dose rate and is capable of linear operation up to 2.5×1012 rad\\/s, (2) the scintillator-photodiode detector measures dose rate only when the

  16. Minimum Bias Trigger Scintillators in ATLAS Run II

    NASA Astrophysics Data System (ADS)

    Sidoti, A.

    2014-10-01

    The Minimum Bias Trigger Scintillators (MBTS) delivered the primary triggers for selecting events from real LHC collisions with the smallest bias for the low luminosity LHC RunI fills from 2009-2013 (proton-proton, lead-lead and lead-proton collisions). Similarly, for the next RunII of LHC (2015-2018) MBTS will provide key ingredients for the first physics measurements at larger LHC collisions energy (charge multiplicity, proton-proton cross section, rapidity gap measurements, ... ) and in general for low luminosity LHC fills. After more than 25 fb-1 of proton-proton collisions delivered during RunI, MBTS detectors have been substantially upgraded in preparation of RunII. The upgrade strategy is presented including the scintillator replacement, the modified read out scheme, the optical measurements on RunI scintillators assessing the degradation due to the dose received.

  17. Scintillation Response of Liquid Xenon to Low Energy Nuclear Recoils

    E-print Network

    E. Aprile; K. L. Giboni; P. Majewski; K. Ni; M. Yamashita; R. Hasty; A. Manzur; D. N. McKinsey

    2005-03-29

    Liquid Xenon (LXe) is expected to be an excellent target and detector medium to search for dark matter in the form of Weakly Interacting Massive Particles (WIMPs). Knowledge of LXe ionization and scintillation response to low energy nuclear recoils expected from the scattering of WIMPs by Xe nuclei is important for determining the sensitivity of LXe direct detection experiments. Here we report on new measurements of the scintillation yield of Xe recoils with kinetic energy as low as 10 keV. The dependence of the scintillation yield on applied electric field was also measured in the range of 0 to 4 kV/cm. Results are in good agreement with recent theoretical predictions that take into account the effect of biexcitonic collisions in addition to the nuclear quenching effect.

  18. Origin of resolution enhancement by co-doping of scintillators: Insight from electronic structure calculations

    E-print Network

    Schleife, André

    ://dx.doi.org/10.1063/1.4880576] Scintillator radiation detectors have many applications in nuclear radiation detectors can be crucially improved by co-doping with Sr, Ca, or Ba. Here, we outline a mechanism of radiation is of particular interest as it enables, for example, the identification of fissile materials.4

  19. Polyvinyltoluene scintillators for relative ion dosimetry: an investigation with Helium, Carbon and Neon beams.

    E-print Network

    Boyer, Edmond

    and the relative dose. Keywords: Scintillation detectors, dosimetry, ion radiation effects, ion the beam or to monitor the dose during irradiation: ionisation chambers, nuclear tracks detectors with Helium, Carbon and Neon beams. David Broggio et al. 2 I. Introduction Different kinds of radiation

  20. Gaseous photomultipliers for the readout of scintillators and detection Cherenkov radiation

    SciTech Connect

    Peskov, V. [Fermi National Accelerator Lab., Batavia, IL (United States); Borovik-Romanov, A. [AN SSSR, Moscow (Russian Federation). Inst. Fizicheskikh Problem

    1993-11-01

    The latest achievements in the development of gaseous detectors for registering UV and visible photons are described. Possible modifications of their design for some particular applications such as the readout of crystal scintillators. noble liquids, fibers and for large area Cherenkov detectors are discussed.

  1. Performance estimation of high resolution SPECT for the human brain by Monte Carlo simulation of scintillation lights

    Microsoft Academic Search

    Y. Hirano; T. Zeniya; H. Watabe; H. Iida

    2009-01-01

    We developed the high resolution SPECT for the human brain. The SPECT has two kinds of detectors. One middle-size detector views whole a head. The other small detector which has extremely resolution (~lmm) views localized region. These detectors are rotated simultaneously. The large detector consists of Nal(Tl) scintillator (15cmx20cm), 15 flat panel type multi-anode PMTs (H8500 Hamamatsu). The performance evaluation,

  2. Plastic scintillation dosimetry: optimization of light collection efficiency.

    PubMed

    Beddar, A Sam; Law, Susan; Suchowerska, Natalka; Mackie, T Rockwell

    2003-05-01

    Practical contemporary radiotherapy dosimetry systems used for dose measurement and verification are ionization chambers (which typically have at least a 0.1 cm3 air cavity volume), thermoluminescent dosimeters (TLDs) and silicon diodes. However, during the last decade, there has been an increased interest in scintillation dosimetry using small water-equivalent plastic scintillators, due to their favourable characteristics when compared with other more commonly used detector systems. Although plastic scintillators have been shown to have many desirable dosimetric properties, as yet there is no successful commercial detector system of this type available for routine clinical use in radiation oncology. The objectives of this study are to identify the factors preventing this new technology from realizing its full potential in commercial applications. A definition of signal to noise ratio (S/N) will be proposed for this category of detectors. In doing so the S/N ratio for an early prototype design has been calculated and/or measured. Criteria to optimize the response and sensitivity of this category of detectors are presented. PMID:12765328

  3. A Monte Carlo investigation of Swank noise for thick, segmented, crystalline scintillators for radiotherapy imaging

    PubMed Central

    Wang, Yi; Antonuk, Larry E.; El-Mohri, Youcef; Zhao, Qihua

    2009-01-01

    Thick, segmented scintillating detectors, consisting of 2D matrices of scintillator crystals separated by optically opaque septal walls, hold considerable potential for significantly improving the performance of megavoltage (MV) active matrix, flat-panel imagers (AMFPIs). Initial simulation studies of the radiation transport properties of segmented detectors have indicated the possibility of significant improvement in DQE compared to conventional MV AMFPIs based on phosphor screen detectors. It is therefore interesting to investigate how the generation and transport of secondary optical photons affect the DQE performance of such segmented detectors. One effect that can degrade DQE performance is optical Swank noise (quantified by the optical Swank factor Iopt), which is induced by depth-dependent variations in optical gain. In this study, Monte Carlo simulations of radiation and optical transport have been used to examine Iopt and zero-frequency DQE for segmented CsI:Tl and BGO detectors at different thicknesses and element-to-element pitches. For these detectors, Iopt and DQE were studied as a function of various optical parameters, including absorption and scattering in the scintillator, absorption at the top reflector and septal walls, as well as scattering at the side surfaces of the scintillator crystals. The results indicate that Iopt and DQE are only weakly affected by absorption and scattering in the scintillator, as well as by absorption at the top reflector. However, in some cases, these metrics were found to be significantly degraded by absorption at the septal walls and scattering at the scintillator side surfaces. Moreover, such degradations are more significant for detectors with greater thickness or smaller element pitch. At 1.016 mm pitch and with optimized optical properties, 40 mm thick segmented CsI:Tl and BGO detectors are predicted to provide DQE values of ?29% and 42%, corresponding to improvement by factors of ?29 and 42, respectively, compared to that of conventional MV AMFPIs. PMID:19673222

  4. Secondary scintillation yield in high-pressure xenon gas for neutrinoless double beta decay (0???) search

    NASA Astrophysics Data System (ADS)

    Freitas, E. D. C.; Monteiro, C. M. B.; Ball, M.; Gómez-Cadenas, J. J.; Lopes, J. A. M.; Lux, T.; Sánchez, F.; dos Santos, J. M. F.

    2010-02-01

    The search for neutrinoless double beta decay (0???) is an important topic in contemporary physics with many active experiments. New projects are planning to use high-pressure xenon gas as both source and detection medium. The secondary scintillation processes available in noble gases permit large amplification with negligible statistical fluctuations, offering the prospect of energy resolution approaching the Fano factor limit. This Letter reports results for xenon secondary scintillation yield, at room temperature, as a function of electric field in the gas scintillation gap for pressures ranging from 2 to 10 bar. A Large Area Avalanche Photodiode (LAAPD) collected the VUV secondary scintillation produced in the gas. X-rays directly absorbed in the LAAPD are used as a reference for determining the number of charge carriers produced by the scintillation pulse and, hence, the number of photons impinging the LAAPD. The number of photons produced per drifting electron and per kilovolt, the so-called scintillation amplification parameter, displays a small increase with pressure, ranging from 141±6 at 2 bar to 170±10 at 8 bar. In our setup, this parameter does not increase above 8 bar due to non-negligible electron attachment. The results are in good agreement with those presented in the literature in the 1 to 3 bar range. The increase of the scintillation amplification parameter with pressure for high gas densities has been also observed in former work at cryogenic temperatures.

  5. Daya Bay Antineutrino Detector Gas System

    E-print Network

    Band, H R; Chu, M-C; Heeger, K M; Kwok, M W; Shih, K; Wise, T; Xiao, Q

    2012-01-01

    The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experiment. This constant flush also prevents the infiltration of radon or other contaminants into these detecting liquids keeping the internal backgrounds low. Since the Daya Bay antineutrino detectors are immersed in the large water pools of the muon veto system, other gas volumes are needed to protect vital detector cables or gas lines. These volumes are also purged with dry gas. Return gas is monitored for oxygen content and humidity to provide early warning of potentially damaging leaks. The design and performance of the Daya...

  6. Lithium-loaded liquid scintillators

    DOEpatents

    Dai, Sheng (Knoxville, TN); Kesanli, Banu (Mersin, TR); Neal, John S. (Knoxville, TN)

    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.

  7. Scintillation light transport and detection

    SciTech Connect

    Gabriel, T.A.; Lillie, R.A.

    1986-08-01

    The MORSE neutron gamma-ray transport code has been modified to allow for the transport of scintillation light. This modified code is used to analyze the light collection characteristics of a large liquid scintillator module (18 x 18 x 350 cm/sup 3/).

  8. Scintillation light transport and detection

    NASA Astrophysics Data System (ADS)

    Gabriel, T. A.; Lillie, R. A.

    1987-08-01

    The MORSE neutron gamma-ray transport code has been modified to allow for the transport of scintillation light. This modified code is used to analyze the light collection characteristics of a large liquid scintillator module (18 × 18 × 350 cm 3).

  9. Characterization of Silicon Photomultiplier Detectors using Cosmic Radiation

    NASA Astrophysics Data System (ADS)

    Zavala, Favian; Castro, Juan; Niduaza, Rexavalmar; Wedel, Zachary; Fan, Sewan; Ritt, Stefan; Fatuzzo, Laura

    2014-03-01

    The silicon photomultiplier light detector has gained a lot of attention lately in fields such as particle physics, astrophysics, and medical physics. Its popularity stems from its lower cost, compact size, insensitivity to magnetic fields, and its excellent ability to distinguish a quantized number of photons. They are normally operated at room temperature and biased above their breakdown voltages. As such, they may also exhibit properties that may hinder their optimal operation which include a thermally induced high dark count rate, after pulse effects, and cross talk from photons in nearby pixels. At this poster session, we describe our data analysis and our endeavor to characterize the multipixel photon counter (MPPC) detectors from Hamamatsu under different bias voltages and temperature conditions. Particularly, we describe our setup which uses cosmic rays to induce scintillation light delivered to the detector by wavelength shifting optical fibers and the use of a fast 1 GHz waveform sampler, the domino ring sampler (DRS4) digitizer board. Department of Education grant number P031S90007.

  10. Silicon photomultiplier choice for the scintillating fibre tracker in second generation proton computed tomography scanner

    SciTech Connect

    Gearhart, A.; Johnson, E.; Medvedev, V.; /Northern Illinois U.; Ronzhin, A.; /Fermilab; Rykalin, V.; /Northern Illinois U.; Rubinov, P.; /Fermilab; Sleptcov, V.; /Unlisted, RU

    2012-03-01

    Scintillating fibers are capable of charged particle tracking with high position resolution, as demonstrated by the central fiber tracker of the D0 experiment. The charged particles will deposit less energy in the polystyrene scintillating fibers as opposed to a typical silicon tracker of the same thickness, while SiPM's are highly efficient at detecting photons created by the passage of the charged particle through the fibers. The current prototype of the Proton Computed Tomography (pCT) tracker uses groups of three 0.5 mm green polystyrene based scintillating fibers connected to a single SiPM, while first generation prototype tracker used Silicon strip detectors. The results of R&D for the Scintillating Fiber Tracker (SFT) as part of the pCT detector are outlined, and the premise for the selection of SiPM is discussed.

  11. Neutron coincidence detectors employing heterogeneous materials

    DOEpatents

    Czirr, J. Bartley (Mapleton, UT); Jensen, Gary L. (Orem, UT)

    1993-07-27

    A neutron detector relies upon optical separation of different scintillators to measure the total energy and/or number of neutrons from a neutron source. In pulse mode embodiments of the invention, neutrons are detected in a first detector which surrounds the neutron source and in a second detector surrounding the first detector. An electronic circuit insures that only events are measured which correspond to neutrons first detected in the first detector followed by subsequent detection in the second detector. In spectrometer embodiments of the invention, neutrons are thermalized in the second detector which is formed by a scintillator-moderator and neutron energy is measured from the summed signals from the first and second detectors.

  12. The balloon-borne electron telescope with scintillating fibers (BETS)

    NASA Astrophysics Data System (ADS)

    Torii, S.; Tamura, T.; Tateyama, N.; Yoshida, K.; Ouchi, Y.; Yamagami, T.; Saito, Y.; Murakami, H.; Kobayashi, T.; Komori, Y.; Kasahara, K.; Yuda, T.; Nishimura, J.

    2000-09-01

    We describe a new detector system developed for high-altitude balloon flights to observe the cosmic-ray electrons above 10 GeV. The Balloon borne Electron Telescope with Scintillating (BETS) fibers instrument is an imaging calorimeter which is capable of selecting electrons against the large background of protons. The calorimeter is composed of a sandwich of scintillating optical-fiber belts and lead plates with a combination of three plastic scintillators for shower trigger. The total thickness of lead is 40mm (~7.1r.l.) and the number of fiber belts is nine. In each belt, alternating layers are oriented in orthogonal (/x and /y) directions. Two sets of an intensified CCD camera are adopted for read-out of the scintillating fibers in the /x and /y direction, respectively. The accelerator beam tests were carried out to study the performance of detector for electrons in 1996 and for protons in 1997 at CERN-SPS. The instrument was successfully flown aboard high-altitude balloon in 1997 and 1998. It is demonstrated by the flight data that a reliable identification of the electron component has been achieved in 10-100GeV and the energy spectrum has been obtained.

  13. 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.

  14. A simple technique for gamma ray and cosmic ray spectroscopy using plastic scintillator

    E-print Network

    Nandan, Akhilesh P; Neog, Himangshu; Bhuyan, M R; Biswas, S; Mahapatra, S; Mohanty, B; Mohanty, Rudranarayan; Rout, Subasha; Sahu, P K; Sahu, S; Sakthivel, V A; Samal, P K

    2014-01-01

    A new and simple technique has been developed using plastic scintillator detectors for gamma ray and cosmic ray spectroscopy without single channel analyzer (SCA) or multichannel analyzer (MCA). In these experiments only a leading edge discriminator (LED) and NIM scalers have been used. Energy calibration of gamma spectra in plastic scintillators has been done using Co60 and Cs137 sources. The details experimental technique, analysis procedure and experimental results has been presented in this article.

  15. A scintillating fiber-optic active target (SFT) for studies of high energy photoproduction

    Microsoft Academic Search

    R. Ruchti; B. Baumbaugh; J. Bishop; J. Busenitz; N. Cason; J. Cunningham; R. Gardner; C. Kennedy; E. Mannel

    1987-01-01

    A high resolution, gateable, Scintillating Fiber Target (SFT) has been developed for Fermilab Experiment E687 to study charm and beauty particle production and decay in high energy photon interactions. The detector consists of a scintillating target of either GS1 Cerium glass fibers or polystyrene fibers of 29..mu..m cross section, a multi-stage image intensifier and an intensified CCD or SIT\\/VIDICON camera

  16. A scintillating fiber-optic active target (SFT) for studies of high energy photoproduction

    Microsoft Academic Search

    R. Ruchti; B. Baumbaugh; J. Bishop; J. Busenitz; N. Cason; J. Cunningham; R. Gardner; C. Kennedy; E. Mannel; D. Puseljic; W. Shephard; M. Zanabria; A. Baumbaugh; K. Knickerbocker; A. Rogers

    1988-01-01

    A high resolution, gateable, Scintillating Fiber Target (SFT) has been developed for Fermilab Experiment E687 to study charm and beauty particle production and decay in high energy photon interactions. The detector consists of a scintillating target of either GS1 Cerium glass fibers or polystyrene fibers of 29..mu..m cross section, a multi-stage image intensifier and an intensified CCD or SIT\\/VIDICON camera

  17. A scintillating fiber-optic active target (SFT) for studies of high energy photoproduction

    SciTech Connect

    Ruchti, R.; Baumbaugh, B.; Bishop, J.; Busenitz, J.; Cason, N.; Cunningham, J.; Gardner, R.; Kennedy, C.; Mannel, E.; Mountain, R.J.

    1988-02-01

    A high resolution, gateable, Scintillating Fiber Target (SFT) has been developed for Fermilab Experiment E687 to study charm and beauty particle production and decay in high energy photon interactions. The detector consists of a scintillating target of either GS1 Cerium glass fibers or polystyrene fibers of 29..mu..m cross section, a multi-stage image intensifier and an intensified CCD or SIT/VIDICON camera system used in conjunction with a custom-built video data acquisition system.

  18. Performance evaluation of a PET demonstrator for PET-MR imaging based on monolithic LYSO:Ce scintillators

    NASA Astrophysics Data System (ADS)

    Sarasola, I.; Cuerdo, R.; Navarrete, J.; García de Acilu, P.; Rato Mendes, P.; Cela, J. M.; Oller, J. C.; Romero, L.; Willmott, C.

    2011-12-01

    We are developing a positron emission tomography (PET) insert based on avalanche photodiode (APD) arrays and monolithic LYSO:Ce scintillators for human brain functional studies to be used inside a clinical magnetic resonance imaging (MRI) equipment. In a previous work [1], we demonstrated the performance of our detectors by implementing an experimental setup consisting of two monolithic blocks working in coincidence, which were read out by the first version of an application-specific integrated circuit (ASIC), VATA240, followed by external coincidence and digitalization modules. This preliminary demonstrator showed good spatial resolution at detector level on the order of 2.2 mm full-width at half-maximum (FWHM) and good imaging qualities, which achieved reconstructed images of 22Na point sources with spatial resolutions of 2.1 mm FWHM. Nevertheless, we detected image distortions and compressions due to the non-linearities close to the edge of the crystals and the simplicity of that demonstrator with the absence of neighbor blocks [1]. In this work we have implemented a larger scale PET demonstrator, which is based on the new updated ASIC (VATA241) [2] and is formed by two sectors of four monolithic detector blocks placed face-to-face. This new prototype demonstrator has been built for validating the data readout architecture, the coincidence processing implemented in a Xilinx Virtex 5 field programmable gate array (FPGA), as well as the continuous neural networks (NN) training method required to determine the points of entrance over the surface of our monolithic detector blocks.

  19. Studying the response of a plastic scintillator to gamma rays using the Geant4 Monte Carlo code.

    PubMed

    Ghadiri, Rasoul; Khorsandi, Jamshid

    2015-05-01

    To determine the gamma ray response function of an NE-102 scintillator and to investigate the gamma spectra due to the transport of optical photons, we simulated an NE-102 scintillator using Geant4 code. The results of the simulation were compared with experimental data. Good consistency between the simulation and data was observed. In addition, the time and spatial distributions, along with the energy distribution and surface treatments of scintillation detectors, were calculated. This simulation makes us capable of optimizing the photomultiplier tube (or photodiodes) position to yield the best coupling to the detector. PMID:25725326

  20. Reflectance of Polytetrafluoroethylene (PTFE) for Xenon Scintillation Light

    E-print Network

    Silva, C; Pereira, A; Chepel, V; Lopes, M I; Solovov, V

    2009-01-01

    Gaseous and liquid xenon particle detectors are being used in a number of applications including dark matter search and neutrino-less double beta decay experiments. Polytetrafluoroethylene (PTFE) is often used in these detectors both as electrical insulator and as a light reflector to improve the efficiency of detection of scintillation photons. However, xenon emits in the vacuum ultraviolet wavelength region (175 nm) where the reflecting properties of PTFE are not sufficiently known. In this work we report on measurements of PTFE reflectance, including its angular distribution, for the xenon scintillation light. Various samples of PTFE, manufactured by different processes (extruded, expanded, skived and pressed) have been studied. The data were interpreted with a physical model comprising both specular and diffuse reflections. The reflectance obtained for these samples ranges from about 47% to 66% for VUV light. Fluoropolymers, namely ETFE, FEP and PFA were also measured.