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1

Ionizations scintillation detectors  

NASA Astrophysics Data System (ADS)

A few references are made to factors which affect the energy resolution of proportional scintillation. The coupling of proportional or primary scintillation devices to photoionization detectors (PIPS chamber) is considered, both in the gas and liquid phases, and using the data available some information is given concerning its expected characteristics of energy, position and time resolution.

Policarpo, A. J. P. L.

2

Time and position distributions in large volume spherical scintillation detectors  

Microsoft Academic Search

Large spherical scintillation detectors are playing an increasingly important role in experimental neutrino physics studies. From the instrumental point of view, the primary signal response of these set-ups is constituted by the time and amplitude of the anode pulses delivered by each individual phototube following a particle interaction in the scintillator. In this work, under some approximate assumptions, we derive

Paolo Lombardi; Gioacchino Ranucci

2007-01-01

3

Shifting scintillator neutron detector  

DOEpatents

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

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

2014-03-04

4

Setup and operation of gamma-ray measurement systems to maximize detector lifetime and stability  

Microsoft Academic Search

The details for optimizing gamma-ray measurement system for specific applications are not always well understood. The setup and operation of a system plays an important role in performance aspects such as maximizing detector lifetime, stability and minimizing the signal to noise ratio. In addition to system setup and operation, the effects of scintillation detector design and accompanying electronics (PMT) are

David G. Penn; Carlos M. Grodsinsky

1999-01-01

5

Silicon photomultiplier characterization with a scintillating bar detector  

NASA Astrophysics Data System (ADS)

This paper describes a setup dedicated to the test of silicon photomultipliers interfaced to a scintillating bar detector. The main item of the setup is a scintillator bar tracker made of extruded bars, readout with wavelength shifter fibers: multiple configurations in terms of number of fibers and readout bar sides are available to test different readout approaches. This setup has been used to test the prototype SiPMs produced by FBK-irst which are characterized by a larger fill factor and photodetection efficiency with respect to standard devices. The SiPMs have been characterized in terms of efficiency, signal to noise ratio and mean photoelectron number using cosmic rays.

Berra, A.; Bonvicini, V.; Ferri, A.; Lietti, D.; Paternoster, G.; Piemonte, C.; Prest, M.; Vallazza, E.

2014-06-01

6

Unitary scintillation detector and system  

DOEpatents

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.

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

1994-01-01

7

The most powerful scintillator supernovae detector: LVD  

Microsoft Academic Search

Summary The Large Volume Detector (LVD) in the Gran Sasso underground Laboratory is a multipurpose detector consisting of a large volume of liquid scintillator interleaved with limited streamer tubes. In this paper we discuss its power to study low-energy cosmic neutrinos. The results show that the first LVD tower (368 tons of liquid scintillator) is well suited to detect neutrinos

M. Aglietta; B. Alpat; E. D. Alyea; P. Antonioli; G. Anzivino; G. Badino; Y. Ban; G. Bari; M. Basile; A. Benelli; V. S. Berezinsky; L. Bergamasco; S. Bianco; A. Bizzetti; G. Bruni; Y. Cao; G. Cara Romeo; R. Casaccia; C. Castagnoli; A. Castellina; K. Chen; R. Chen; J. A. Chinellato; L. Cifarelli; G. Cini; S. Cong; A. Contin; V. L. Dadikin; M. Dardo; A. De Silva; M. Deutsch; L. G. Dos Santos; R. I. Enikeev; F. L. Fabbri; W. Fulgione; P. Galeotti; P. L. Ghia; P. Giusti; F. Grianti; S. Gu; E. S. Hafen; P. Haridas; G. Iacobucci; N. Inoue; F. F. Khalchukov; E. V. Korolkova; P. V. Kortchaguin; V. B. Kortchaguin; V. A. Kudryavtsev; G. Landi; K. Lau; X. Lin; L. Lu; J. Ma; Z. Ma; G. Maccarrone; A. S. Malguin; Z. Mao; M. A. Markov; T. Massam; B. Mayes; N. Mengotti Silva; A. Misaki; G. H. Mo; B. Monteleoni; C. Morello; J. Moromisato; R. Nania; G. Navarra; L. Panaro; D. Parks; P. G. Pelfer; L. Periale; P. Picchi; P. Pinna; L. Pinsky; I. A. Pless; M. Pu; J. Pyrlyk; J. Qiu; V. G. Ryasny; O. G. Ryazhskaya; O. Saavedra; K. Saitoh; D. Sanders; G. Sartorelli; S. Sarwar; D. Shen; V. P. Talochkin; H. Tang; J. Tang; W. Tian; G. C. Trinchero; A. Turtelli; I. Uman; P. Vallania; S. Vernetto; E. von Goeler; L. Votano; T. Wada; F. Wang; H. Wang; S. Wang; R. Weathers; R. Weinstein; M. Widgoff; L. Xu; Z. Xu; V. F. Yakushev; I. Yamamoto; G. Yi; A. Zallo; G. T. Zatsepin; X. Zhou; Q. Zhu; X. Zhu; B. Zhuan; A. Zichichi

1992-01-01

8

Neutron position-sensitive scintillation detector  

DOEpatents

A device is provided for mapping one- and two-dimensional distributions of neutron-positions in a scintillation detector. The device consists of a lithium glass scintillator coupled by an air gap and a light coupler to an array of photomultipliers. The air gap concentrates light flashes from the scintillator, whereas the light coupler disperses this concentrated light to a predetermined fraction of the photomultiplier tube array.

Strauss, Michael G. (Downers Grove, IL); Brenner, Raul (Woodridge, IL)

1984-01-01

9

A mobile antineutrino detector with plastic scintillators  

E-print Network

We propose a new type segmented antineutrino detector made of plastic scintillators for the nuclear safeguard application. A small prototype was built and tested to measure background events. A satisfactory unmanned field operation of the detector system was demonstrated. Besides, a detailed Monte Carlo simulation code was developed to estimate the antineutrino detection efficiency of the detector.

Yasuhiro Kuroda; Shugo Oguri; Yo Kato; Ryoko Nakata; Yoshizumi Inoue; Chikara Ito; Makoto Minowa

2012-06-28

10

Scintillation detectors of Alborz-I experiment  

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

11

Scintillating fiber detector performance, detector geometries, trigger, and electronics issues for scintillating fiber tracking  

SciTech Connect

Scintillating Fiber tracking technology has made great advances and has demonstrated great potential for high speed charged particle tracking and triggering. The small detector sizes and fast scintillation fluors available make them very promising for use at high luminosity experiments at today`s and tomorrow`s colliding and fixed target experiments where high rate capability is essential. This talk will discuss the current state of Scintillating fiber performance and current Visual Light Photon Counter (VLPC) characteristics. The primary topic will be some of the system design and integration issues which should be considered by anyone attempting to design a scintillating fiber tracking system which includes a high speed tracking trigger. Design. constraints placed upon the detector system by the electronics and mechanical sub-systems will be discussed. Seemingly simple and unrelated decisions can have far reaching effects on overall system performance. SDC and DO example system designs will be discussed.

Baumbaugh, A.E.

1994-06-01

12

Nanocomposite scintillator, detector, and method  

DOEpatents

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.

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

13

Liquid scintillation detectors for high energy neutrinos  

NASA Astrophysics Data System (ADS)

Large liquid scintillation detectors have been generally used for low energy neutrino measurements, in the MeV energy region. We describe the potential employment of large detectors (>1 kiloton) for studies of higher energy neutrino interactions, such as cosmic rays and long baseline experiments. When considering the physics potential of new large instruments the possibility of doing useful measurements with higher energy neutrino interactions has been overlooked. Here we take into account Fermat’s principle, which states that the first light to reach each PMT will follow the shortest path between that PMT and the point of origin. We describe the geometry of this process, and the resulting wavefront, which we call the “Fermat surface”, and discuss methods of using this surface to extract directional track information and particle identification. This capability may be demonstrated in the new long baseline neutrino beam from Jaeri accelerator to the KamLAND detector in Japan. Other exciting applications include the use of Hanohano as a movable long baseline detector in this same beam, and LENA in Europe for future long baseline neutrino beams from CERN. Also, this methodology opens up the question as to whether a large liquid scintillator detector should be given consideration for use in a future long baseline experiment from Fermilab to the DUSEL underground laboratory at Homestake.

Smith, Stefanie N.; Learned, John G.

2010-04-01

14

Liquid Scintillation Detectors for High Energy Neutrinos  

SciTech Connect

Large open volume (not segmented) liquid scintillation detectors have been generally dedicated to low energy neutrino measurements, in the MeV energy region. We describe the potential employment of large detectors (>1 kiloton) for studies of higher energy neutrino interactions, such as cosmic rays and long-baseline experiments. When considering the physics potential of new large instruments the possibility of doing useful measurements with higher energy neutrino interactions has been overlooked. Here we take into account Fermat's principle, which states that the first light to reach each PMT will follow the shortest path between that PMT and the point of origin. We describe the geometry of this process, and the resulting wavefront, which we are calling the 'Fermat surface', and discuss methods of using this surface to extract directional track information and particle identification. This capability may be demonstrated in the new long-baseline neutrino beam from Jaeri accelerator to the KamLAND detector in Japan. Other exciting applications include the use of Hanohano as a movable long-baseline detector in this same beam, and LENA in Europe for future long-baseline neutrino beams from CERN. Also, this methodology opens up the question as to whether a large liquid scintillator detector should be given consideration for use in a future long-baseline experiment from Fermilab to the DUSEL underground laboratory at Homestake.

Smith, Stefanie N.; Learned, John G. [Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

2010-03-30

15

Liquid Scintillation Detectors for High Energy Neutrinos  

NASA Astrophysics Data System (ADS)

Large open volume (not segmented) liquid scintillation detectors have been generally dedicated to low energy neutrino measurements, in the MeV energy region. We describe the potential employment of large detectors (>1 kiloton) for studies of higher energy neutrino interactions, such as cosmic rays and long-baseline experiments. When considering the physics potential of new large instruments the possibility of doing useful measurements with higher energy neutrino interactions has been overlooked. Here we take into account Fermat's principle, which states that the first light to reach each PMT will follow the shortest path between that PMT and the point of origin. We describe the geometry of this process, and the resulting wavefront, which we are calling the "Fermat surface", and discuss methods of using this surface to extract directional track information and particle identification. This capability may be demonstrated in the new long-baseline neutrino beam from Jaeri accelerator to the KamLAND detector in Japan. Other exciting applications include the use of Hanohano as a movable long-baseline detector in this same beam, and LENA in Europe for future long-baseline neutrino beams from CERN. Also, this methodology opens up the question as to whether a large liquid scintillator detector should be given consideration for use in a future long-baseline experiment from Fermilab to the DUSEL underground laboratory at Homestake.

Smith, Stefanie N.; Learned, John G.

2010-03-01

16

Temperature dependence of BCF plastic scintillation detectors  

PubMed Central

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

Wootton, Landon; Beddar, Sam

2013-01-01

17

Scintillation detectors based on silicon microfluidic channels  

NASA Astrophysics Data System (ADS)

Microfluidic channels obtained by SU-8 photolithography and filled with liquid scintillators were recently demonstrated to be an interesting technology for the implementation of novel particle detectors. The main advantages of this approach are the intrinsic radiation resistance resulting from the simple microfluidic circulation of the active medium and the possibility to manufacture devices with high spatial resolution and low material budget using microfabrication techniques. Here we explore a different technological implementation of this concept, reporting on scintillating detectors based on silicon microfluidic channels. A process for manufacturing microfluidic devices on silicon substrates, featuring microchannel arrays suitable for light guiding, was developed. Such process can be in principle combined with standard CMOS processing and lead to a tight integration with the readout photodetectors and electronics in the future. Several devices were manufactured, featuring microchannel geometries differing in depth, width and pitch. A preliminary characterization of the prototypes was performed by means of a photomultiplier tube coupled to the microchannel ends, in order to detect the scintillation light produced upon irradiation with beta particles from a 90Sr source. The photoelectron spectra thus obtained were fitted with the expected output function in order to extract the light yield.

Maoddi, P.; Mapelli, A.; Bagiacchi, P.; Gorini, B.; Haguenauer, M.; Lehmann Miotto, G.; Murillo Garcia, R.; Safai Tehrani, F.; Veneziano, S.; Renaud, P.

2014-01-01

18

Scintillating ribbon x-ray detector  

SciTech Connect

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.

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

1995-12-31

19

Setup and operation of gamma-ray measurement systems to maximize detector lifetime and stability  

NASA Astrophysics Data System (ADS)

The details for optimizing gamma-ray measurement system for specific applications are not always well understood. The setup and operation of a system plays an important role in performance aspects such as maximizing detector lifetime, stability and minimizing the signal to noise ratio. In addition to system setup and operation, the effects of scintillation detector design and accompanying electronics (PMT) are discussed with respect to both gross counting and spectroscopy measurements in order to obtain reliable results. Data has been taken with various sodium iodide scintillation detectors to study system stability during transient such as power cycling and count rate fluctuations. These fluctuations may introduce substantial measurement uncertainty, and if not accounted for will propagate into an analyses. The above transients can also affect the detector lifetime, and if the system conditions are monitored properly, they can be used as a predictive tool for determining the useful life of a detector. Data is also presented to examine counting statistics in an overlapping spectrum as a function of spectral resolution and count rate. The objective is to determine the optimum counting time for the spectrum to reach a statistically stable shape. The data is reduced by examining the standard deviation of fitted Gaussian curves at ten second intervals. The result is a contour plat showing the time needed to reach stability, which increase with spectral resolution and decrease with a rising count rate.

Penn, David G.; Grodsinsky, Carlos M.

1999-10-01

20

Development of tracking detectors based on capillaries with liquid scintillator  

NASA Astrophysics Data System (ADS)

Capillaries with a liquid scintillator used for high resolution tracking detectors have been investigated. The highest scintillation efficiency, 1.5 times higher than that of a standard polystyrene scintillator, has been attained for the solution of 1-methylnaphthalene with pyrasoline type dye MDP. The time properties of this liquid scintillator and locality of light emission have been studied. Light attenuations in quartz capillaries of different diameters have been measured. For the optimal concentration of MDP the attenuation lengths for capillaries of 30 and 60 ?m in diameter were 41 cm and 53 cm, respectively. For high resolution tracking detectors capillaries with a liquid scintillator are quite competitive with plastic fibres.

Golovkin, S. V.; Gorin, A. M.; Kulichenko, A. V.; Kushnirenko, A. E.; Peresypkin, A. I.; Pyshchev, A. I.; Rykalin, V. I.; Zaichenko, A. A.

1991-07-01

21

Nonproportionality of Scintillator Detectors: Theory and Experiment  

SciTech Connect

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.

Payne, Stephen; Cherepy, Nerine; Hull, Giulia; Valentine, John; Moses, William; Choong, Woon-Seng

2009-08-17

22

The UA2 scintillating fibre detector  

NASA Astrophysics Data System (ADS)

The UA2 experiment at CERN is currently upgrading its apparatus to take advantage of the higher accelerator luminosity to be provided from November 1987. The first large particle tracking detector using scintillating optical fibres will form a major part of this upgrade. The detector is built by the Cambridge, CERN and Saclay groups. The Scintillating Fibre Detector is a cylinder of radius 38 to 44 cm, composed of 60000 plastic optical fibres of length over 2 m. The 1 mm diameter fibres are optically clad and aluminised, and are arranged in 24 layers. The detector will be used to track charged particles produced in pp interactions, and also contains a lead converter to cause neutral and charged electromagnetic particles to shower. The signals from the fibres are amplified, multiplexed and digitised by 32 readout chains. These consist of: —A large aperture, de-magnifying image intensifier, providing a gain of ˜ 40000. Extremely fast phosphors are employed for the three stages, to match the short time (4 ps) between particle interactions; —Charge-coupled devices (CCDs) converting the optical image into a single train of electrical pulses for 2000 fibres. A novel use of the anti-blooming electrode of the CCD enables unwanted images to be cleared in <1 ps; —A Fastbus digitiser, which processes the video signal, providing a large degree of data reduction. A full-scale prototype of 960 fibres with readout has been tested in a particle beam. It has demonstrated a good spatial resolution of the tracks (< 0.20 mm), and an excellent discrimination between electrons and hadrons based on the light detected after the converter.

Ansorge, R. E.; Anrouet, C.; Bareyre, P.; Bonamy, P.; Booth, C. N.; Bouchard, M.; Bourdinaud, M.; Cordier, M.; Crittenden, J.; Dewolf, R. S.; Dupont, J.; Dupraz, J.; Einsweiler, K.; Engster, C.; Fabre, J.-P.; Gaillard, J.-M.; Garavel, J.-L.; Hultqvist, K.; Jeanney, C.; Katvars, S. G.; Lefebvre, M.; Linssen, L.; McCluskey, B.; Merkel, B.; Meyer, J.-P.; Munday, D. J.; Nappey, P.; Pentney, J. M.; Reynaud, S.; Rushbrooke, J. G.; Thevenin, J.-C.; Tsang, W. Y.; Weidberg, A. R.; Wells, P. S.; Wotton, S. A.; White, T. O.; Zaccone, H.

1988-12-01

23

TOF-PET detector concept based on organic scintillators  

E-print Network

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.

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

24

Fundamental limits of scintillation detector timing precision.  

PubMed

In this paper we review the primary factors that affect the timing precision of a scintillation detector. Monte Carlo calculations were performed to explore the dependence of the timing precision on the number of photoelectrons, the scintillator decay and rise times, the depth of interaction uncertainty, the time dispersion of the optical photons (modeled as an exponential decay), the photodetector rise time and transit time jitter, the leading-edge trigger level, and electronic noise. The Monte Carlo code was used to estimate the practical limits on the timing precision for an energy deposition of 511 keV in 3 mm × 3 mm × 30 mm Lu2SiO5:Ce and LaBr3:Ce crystals. The calculated timing precisions are consistent with the best experimental literature values. We then calculated the timing precision for 820 cases that sampled scintillator rise times from 0 to 1.0 ns, photon dispersion times from 0 to 0.2 ns, photodetector time jitters from 0 to 0.5 ns fwhm, and A from 10 to 10,000 photoelectrons per ns decay time. Since the timing precision R was found to depend on A(-1/2) more than any other factor, we tabulated the parameter B, where R = BA(-1/2). An empirical analytical formula was found that fit the tabulated values of B with an rms deviation of 2.2% of the value of B. The theoretical lower bound of the timing precision was calculated for the example of 0.5 ns rise time, 0.1 ns photon dispersion, and 0.2 ns fwhm photodetector time jitter. The lower bound was at most 15% lower than leading-edge timing discrimination for A from 10 to 10,000 photoelectrons ns(-1). A timing precision of 8 ps fwhm should be possible for an energy deposition of 511 keV using currently available photodetectors if a theoretically possible scintillator were developed that could produce 10,000 photoelectrons ns(-1). PMID:24874216

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

2014-07-01

25

Optimizing timing performance of silicon photomultiplier-based scintillation detectors.  

PubMed

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

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

2013-02-21

26

High Resolution Scintillating Fiber Gamma Ray Detectors For Medical Imaging  

Microsoft Academic Search

High spatial and time resolution gamma ray detectors have been developed using plastic 'scintillating fibers coupled to position sensitive vacuum photomultipliers under development. These detectors can significantly improve the spatial resolution, time resolution, and efficiency of both SPECT and PET, extend the application of these technologies into new fields of medical research, and improve currently existing methods of medical diagnosis.

M. Atac; D. B. Cline; R. C. Chancy; E. J. Fenyves; G. Hademenos; P. P. Antich; M. D. Petroff

1990-01-01

27

Smaller, Lower-Power Fast-Neutron Scintillation Detectors  

NASA Technical Reports Server (NTRS)

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.

Patel, Jagdish; Blaes, Brent

2008-01-01

28

Scintillation of liquid xenon and its application to nuclear radiation detectors  

Microsoft Academic Search

To understand the superiority of liquid xenon as detector medium, at first, the scintillation mechanism of liquid rare gases is explained and the absolute scintillation yield in liquid xenon is estimated and then the decay shapes of scintillation lights from liquid xenon, which are faster than those of scintillation lights from crystal scintillators recently developed, are summarized. In addition, only

T. Doke

2005-01-01

29

Scintillation of liquid xenon and its application to nuclear radiation detectors  

Microsoft Academic Search

We review the scintillation mechanism of liquid rare gases and estimate the absolute scintillation yield of liquid xenon in order to understand the superiority of liquid xenon as a detector medium. The decays of scintillation light from liquid xenon, which are faster than those of scintillation light from crystal scintillators, are summarized. New photomultipliers with high quantum efficiency that can

Tadayoshi Doke

2006-01-01

30

The scintillation process in gas proportional scintillation detectors with uniform electric fields  

NASA Astrophysics Data System (ADS)

A model is developed to describe the formation of the secondary scintillation in a gas proportional scintillation detector having a uniform electric field. A simple expression is obtained for the instantaneous rate of emission of photons from the scintallator, assuming that the dominant excitation process in the gas is excitation by electron impact. The results of an experimental investigation of the photon emission from xenon following ionization of the gas by ?-particles are presented. Our observations at various gas pressures and electric intensities are shown, with the aid of the model, to be consistent with those which have been obtained by other workers using parallel plate gas proportional scintillation detectors of significantly different design and mode of operation and exposed to X-rays as well as ?-particles.

Cumpstey, D. E.; Vass, D. G.

1980-05-01

31

Scintillation detectors in gamma spectral logging; geometry, absorption and calibration  

USGS Publications Warehouse

The theory for the evaluation of the effects of geometry in gamma ray absorption is developed for cylindrical scintillation detectors as applicable to borehole gamma spectrometry. The results of a laboratory experiment are shown for comparison. A calibration procedure to determine detector efficiency is given for application to borehole probes. It is shown that the response of a crystal can be separated in terms of geometric effects and instrumentation effects. It is also shown that approximating crystal detectors with point detectors in mathematical theory is grossly oversimplified. (USGS)

Schimschal, Ulrich

1980-01-01

32

Response and noise characteristics of small-sized inorganic and organic scintillation detectors measured with vacuum and solid-state photodetectors  

NASA Astrophysics Data System (ADS)

Response and noise properties of scintillation detectors were investigated using a 137Cs radioactive source. The experimental setup consisted of a scintillator, photodetector, amplifier, and spectrometric analog-to-digital converter. Small-sized, cubic crystals were manufactured of stilbene, p-terphenyl and thallium-doped cesium iodide, as well as of a plastic scintillator material based on polystyrene. Vacuum and solid-state photomultipliers and a silicon PIN photodiode were used as photodetectors. The energy equivalent noise was determined for all used photodetectors. The response of various scintillators when using vacuum and semiconductor photomultipliers was found to be closely similar.

Dudnik, O. V.; Kurbatov, E. V.; Tarasov, V. A.; Andryushenko, L. A.; Boyarintsev, A. Yu.; Valtonen, E.

2012-02-01

33

The time resolution of bismuth germanate scintillation detectors  

NASA Astrophysics Data System (ADS)

The time resolution of a bismuth germanate scintillation detector was measured as a function of ?-ray energy from 1 MeV to 24 MeV. The measured time resolution of the 60Co cascade is (2.1±0.2)ns. The time resolution improves at higher ?-ray energies and is (890±60) ps at around 20 MeV.

Wender, S. A.; Auchampaugh, G. F.; Hill, N. W.

1982-06-01

34

A scintillating fission detector for neutron flux measurements  

SciTech Connect

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.

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

35

Active Inspection of Nuclear Materials Using 4He Scintillation Detectors  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

36

Bismuth germanate as a potential scintillation detector in positron cameras.  

PubMed

Timing and energy resolutions of the bismuth germanate (Bi4Ge3O12) scintillation crystals were studied, with particular respect to a positron-camera application. In comparison with the NaI(Tl) system, the detection efficiency for annihilation radiation is more than triple, and coincidence detection efficiency is more than ten times as good. This paper explores the properties of the new scintillator material and their bearing on the spatial resolution and the efficiency of coincidence detection in positron cameras with stationary ring detectors. PMID:874173

Cho, Z H; Farukhi, M R

1977-08-01

37

Modelling of scintillator based flat-panel detectors with Monte-Carlo simulations  

NASA Astrophysics Data System (ADS)

Scintillator based flat panel detectors are state of the art in the field of industrial X-ray imaging applications. Choosing the proper system and setup parameters for the vast range of different applications can be a time consuming task, especially when developing new detector systems. Since the system behaviour cannot always be foreseen easily, Monte-Carlo (MC) simulations are keys to gain further knowledge of system components and their behaviour for different imaging conditions. In this work we used two Monte-Carlo based models to examine an indirect converting flat panel detector, specifically the Hamamatsu C9312SK. We focused on the signal generation in the scintillation layer and its influence on the spatial resolution of the whole system. The models differ significantly in their level of complexity. The first model gives a global description of the detector based on different parameters characterizing the spatial resolution. With relatively small effort a simulation model can be developed which equates the real detector regarding signal transfer. The second model allows a more detailed insight of the system. It is based on the well established cascade theory, i.e. describing the detector as a cascade of elemental gain and scattering stages, which represent the built in components and their signal transfer behaviour. In comparison to the first model the influence of single components especially the important light spread behaviour in the scintillator can be analysed in a more differentiated way. Although the implementation of the second model is more time consuming both models have in common that a relatively small amount of system manufacturer parameters are needed. The results of both models were in good agreement with the measured parameters of the real system.

Reims, N.; Sukowski, F.; Uhlmann, N.

2011-01-01

38

Photoelectron anticorrelations and sub-Poisson statistics in scintillation detectors  

PubMed Central

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

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

2010-01-01

39

Characterization of indium iodide detectors for scintillation studies  

NASA Astrophysics Data System (ADS)

Indium iodide (InI) is a wide bandgap semiconductor ( Eg = 2.0 eV) and has been investigated as an optical detector material for use in ?-ray scintillation spectroscopy. Single crystals of InI have been grown by the Bridgman process using zone-refined starting material and optical detectors have been fabricated from such crystals. The performance of these detectors has been investigated by measuring their quantum efficiency, direct X-ray detection characteristics, and electrical resistivity. The InI photodetectors have been coupled to Csl(Tl) scintillators and room-temperature energy resolutions of 7.5% (FWHM) and 9.8% (FWHM) were recorded for 662 keV and 511 keV ?-rays, respectively. Successful ?-ray detection has also been accomplished with InI photodetectors coupled to LSO (Lu 2SiO 5:Ce) scintillators, and a resolution of 14% (FWHM) has been recorded for 511 keV ?-rays. Finally, analysis of the electronic noise behavior of the InI detectors has been performed.

Shah, K. S.; Bennett, P.; Moy, L. P.; Misra, M. M.; Moses, W. W.

1996-10-01

40

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

Microsoft Academic Search

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

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

2008-01-01

41

Multilayer Scintillation Detector for Nuclear Physics Monitoring of Space Weather  

NASA Astrophysics Data System (ADS)

The physical characteristics of the multilayer scintillation spectrometer for identification and energy measurement of cosmic electrons, positrons and nuclei are considered in this presentation. The nuclei energy measurement range is 3-100 MeV/nucleon. This spectrometer is planning for space weather monitoring and investigation of solar-magnetospheric and geophysics effects on satellite. These characteristics were estimated by means of computer simulation. The ionization loss fluctuations, ion charge exchange during pass through detector and, especially, scintillation quenching effect (Bircs effect) were taken into account in calculations. The main results are: 1.) Ions mass identification is possible for hydrogen and helium isotopes 2.) Ions charge identification without mass identification is possible for nuclei from lithium to oxygen The preliminary estimation indicate, that including to spectrometer of thin semiconductor detector (SCD) as first layer makes possible charge identification for Z>8. This may be done by means of comparison of ion range in spectrometer with its energy loss in SCD.

Aleksandrin, Sergey; Mayorov, Andrey; Koldashov, Sergey; Batischev, Alexey; Lapushkin, Sergey; Gurov, Yury

42

Optical Scattering Lengths in Large Liquid-Scintillator Neutrino Detectors  

E-print Network

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 PXE, LAB, and Dodecane which are under discussion for next-generation experiments like SNO+, Hanohano, or LENA. Results comprise the wavelength range from 415 to 440nm. 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.

Wurm, Michael; Goeger-Neff, Marianne; Hofmann, Martin; Lachenmaier, Tobias; Lewke, Timo; Undagoitita, Teresa Marrodan; Meindl, Quirin; Moellenberg, Randoplh; Oberauer, Lothar; Potzel, Walter; Tippmann, Marc; Todor, Sebastian; Traunsteiner, Christoph; Winter, Juergen

2010-01-01

43

Design of a high resolution scintillator based SPECT detector (SPECTatress)  

NASA Astrophysics Data System (ADS)

SPECT scanners using multi-pinhole collimators benefit from compact detectors having a high spatial resolution. Such detectors can be placed closer to the collimator and perpendicular to the pinhole axis (thereby limiting DOI spatial resolution degradation). Current clinical gamma ray cameras have a large area and a poor spatial resolution.This proceeding describes the architecture of SPECTatress, a compact high resolution gamma camera. The main components (PMT and scintillator) are presented, a brief overview of the read-out electronics is given and a first measurement using the center-of-gravity (COG) event-positioning algorithm is shown.The result of this measurement indicates a good spatial resolution (1.75 mm FWHM) in the center of the detector. Further research has to be done on the event-positioning algorithm to extend the usable detector area and to enhance the spatial resolution.

Deprez, Karel; van Holen, Roel; Vandenberghe, Stefaan; Staelens, Steven

2011-08-01

44

Antineutrino Geophysics with Liquid Scintillator Detectors  

E-print Network

Detecting the antineutrinos emitted by the decay of radioactive elements in the mantle and crust could provide a direct measurement of the total abundance of uranium and thorium in the Earth. In calculating the antineutrino flux at specific sites, the local geology of the crust and the background from the world's nuclear power reactors are important considerations. Employing a global crustal map, with type and thickness data, and using recent estimates of the uranium and thorium distribution in the Earth, we calculate the antineutrino event rate for two new neutrino detectors. We show that spectral features allow terrestrial antineutrino events to be identified above reactor antineutrino backgrounds and that the uranium and thorium contributions can be separately determined.

Casey G. Rothschild; Mark C. Chen; Frank P. Calaprice

2005-06-01

45

Muon detection with scintillation detectors using indirect SiPM readout  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . 8 2.2.4 Temperature sensors . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3 Setup 10 3 of the scintillator were used to have a comparison between the different light yield. Consequentely different . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.1.2 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.2 Muon

Hebbeker, Thomas

46

Monte Carlo calculations of a bismuth germanate scintillation detector  

NASA Astrophysics Data System (ADS)

Intrinsic efficiency, radial distribution of deposited energy and other properties of importance were investigated for bismuth germanate slabs via Monte Carlo calculation. The calculations were done for different slab thicknesses in the range {1}/{8?-2?}, and over the energy range 140-999 keV. An examination of the data shows the possible advantage of the use of BGO as scintillation detector for high energy gamma ray and positron imaging. The data do not show very strong dependence of the image resolution on the thickness of the slab.

Alkhafaji, Salih M.

47

Atmospheric Neutron Measurements using a Small Scintillator Based Detector  

NASA Astrophysics Data System (ADS)

PoGOLino is a standalone scintillator-based neutron detector designed for balloon-borne missions. Its main purpose is to provide data of the neutron flux in 2 different energy ranges in the high altitude / high latitude region where the highest neutron flux in the atmosphere is found. Furthermore the influence of the Solar activity upon the neutron environment in this region is relatively strong. As a result both short and long term time fluctuations are strongest in this region. At high altitudes neutrons can form a source of background for balloon-borne scientific measurements. They can furthermore form a major source for single event upsets in electronics. A good understanding of the high altitude / high latitude neutron environment is therefore important. Measurements of the neutron environment in this region are however lacking. PoGOLino contains two 5 mm thick Lithium Calcium Aluminium Fluoride (LiCAF) scintillators used for neutron detection. The LiCAF crystals are sandwiched between 2 Bismuth Germanium Oxide (BGO) scintillating crystals, which serve to veto signals produced by gamma-rays and charged particles. The veto system makes measurements of the neutron flux possible even in high radiation environments. One LiCAF detector is shielded with polyethylene while the second remains unshielded, making the detectors sensitive in different energy ranges. The choice of a scintillator crystals as the detection material ensures a high detection efficiency while keeping the instrument small, robust and light weight. The full standalone cylindrical instrument has a radius of 120 mm, a height of 670 mm and a total mass of 13 kg, making it suitable as a piggy back mission. PoGOLino was successfully launched on March 20th 2013 from the Esrange Space Center in Northern Sweden to an altitude of 30.9 km. A detailed description of the detector design is presented, along with results of of the flight. The neutron flux measured during flight is compared to predictions based on PLANETOCOSMICS and Geant4 simulations.

Kole, Merlin; Pearce, Mark; Fukazawa, Yasushi; Fukuda, Kentaro; Ishizu, Sumito; Jackson, Miranda; Kamae, Tune; Kawaguchi, Noriaki; Kawano, Takafumi; Kiss, Mozsi; Moretti, Elena; Yanagida, Takayuki; Chauvin, Maxime; Mikhalev, Victor; Rydstrom, Stefan; Takahashi, Hiromitsu

48

Scintillator strip detector with SiPM readout as detector for a TOF system  

Microsoft Academic Search

The appearance of new photo-sensors, SiPMs, gives a new life to detectors based on solid scintillators. All the advantages of SiPMs have been demonstrated with the construction of the full-scale hadron calorimeter prototype by the CALICE collaboration. New applications are made possible by using strips as the detector element and SiPMs of new generation. Two examples are discussed: a TOF

Vladimir Rusinov

2010-01-01

49

Performance characterization of a new high resolution PET scintillation detector  

PubMed Central

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

Foudray, A M K; Olcott, P D

2013-01-01

50

Multi-layer scintillation detector for the MOON double beta decay experiment: Scintillation photon responses studied by a prototype detector MOON-1  

E-print Network

An ensemble of multi-layer scintillators is discussed as an option of the high-sensitivity detector Mo Observatory Of Neutrinos (MOON) for spectroscopic measurements of neutrino-less double beta decays. A prototype detector MOON-1, which consists of 6 layer plastic-scintillator plates, was built to study the sensitivity of the MOON-type detector. The scintillation photon collection and the energy resolution, which are key elements for the high-sensitivity experiments, are found to be 1835+/-30 photo-electrons for 976 keV electrons and sigma = 2.9+/-0.1% (dE/E = 6.8+/-0.3 % in FWHM) at the Qbb ~ 3 MeV region, respectively. The multi-layer plastic-scintillator structure with good energy resolution as well as good background suppression of beta-gamma rays is crucial for the MOON-type detector to achieve the inverted hierarchy neutrino mass sensitivity.

H. Nakamura; P. Doe; H. Ejiri; S. R. Elliott; J. Engel; M. Finger; M. Finger. Jr; K. Fushimi; V. Gehman; A. Gorin; M. Greenfield; V. H. Hai; R. Hazama; K. Higa; T. Higashiguchi; K. Ichihara; Y. Ikegami; J. Imoto; H. Ishii; T. Itahashi; H. Kaneko; P. Kavitov; H. Kawasuso; V. Kekelidze; K. Matsuoka; T. Mizuhashi; D. Noda; M. Nomachi; K. Onishi; T. Ogama; A. Para; R. G. H. Robertson; M. Sakamoto; T. Sakiuchi; Y. Samejima; Y. Shichijo; T. Shima; Y. Shimada; G. Shirkov; A. Sissakian; M. Slunecka; Y. Sugaya; A. Titov; M. Uenoyama; S. Umehara; A. Urano; V. Vatulin; V. Voronov; J. F. Wilkerson; D. I. Will; K. Yasuda; S. Yoshida; M. Yoshihuku

2006-09-12

51

Design of a high resolution positron emission tomograph using solid state scintillation detectors  

Microsoft Academic Search

The authors propose a new concept of positron camera achieving nearly isotropic spatial resolution and uniform sensitivity throughout the useful field-of-view. The design is based on a quad scintillator dual channel detector module using two avalanche photodiodes as photodetectors. Original features include bilayered scintillators to measure the depth of interaction, tilted detectors relative to the radial direction to insure proper

C. Carrier; C. Martel; D. Schmitt; R. Lecomte

1988-01-01

52

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

Microsoft Academic Search

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

E. Geiger; L. Phyfe; W. Fisher

1985-01-01

53

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

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

54

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

SciTech Connect

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.

Proudfoot, J.

1992-01-01

55

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

PubMed

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. PMID:19175139

Shao, Yiping; Yao, Rutao; Ma, Tianyu

2008-12-01

56

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

SciTech Connect

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.

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

57

Progress on high-resolution tracking with scintillating fibres: a new detector based on capillaries filled with liquid scintillator  

NASA Astrophysics Data System (ADS)

The capabilities of a new detector based on capillaries filled with liquid scintillator have been investigated. Tests have been performed using various scintillating cocktails and readout systems. With the best combinations, and for light propagation over a few centimetres, the hit density is as high as 5 hits/mm. For propagation over distances greater than 10 cm, an attenuation length of ˜95 cm is measured. A spatial resolution of ? ? 12 ?m is obtained with capillaries of 20 ?m bore.

Adinolfi, M.; Angelini, C.; Cardini, A.; Cianfarani, C.; Da Vià, C.; Duane, A.; Fabre, J.-P.; Flaminio, V.; Frenkel, A.; Golovkin, S. V.; Gorin, A. M.; Gruwé, M.; Harrison, K.; Kanerva, M.; Kozarenko, E. N.; Kushnirenko, A. E.; Martellotti, G.; McEwen, J. G.; Morrison, D. R. O.; Penso, G.; Peresypkin, A. I.; Roda, C.; Websdale, D. M.; Wilquet, G.; Zaichenko, A. A.

1992-05-01

58

Measuring Directionality in Double-Beta Decay and Neutrino Interactions with Kiloton-Scale Scintillation Detectors  

E-print Network

Large liquid-scintillator-based detectors have proven to be exceptionally effective for low energy neutrino measurements due to their good energy resolution and scalability to large volumes. The addition of directional information using Cherenkov light and fast timing would enhance the scientific reach of these detectors, especially for searches for neutrino-less double-beta decay. In this paper, we develop a technique for extracting particle direction using the difference in arrival times for Cherenkov and scintillation light, and evaluate several detector advances in timing, photodetector spectral response, and scintillator emission spectra that could be used to make direction reconstruction a reality in a kiloton-scale detector.

C. Aberle; A. Elagin; H. J. Frisch; M. Wetstein; L. Winslow

2014-01-31

59

Multilayer Scintillator Responses for Mo Observatory of Neutrino Experiment Studied Using a Prototype Detector MOON-1  

E-print Network

)-type spectroscopic detector,7) which is based on the ELEGANT V detector,8­10) but is expanded to improve the half-life a Prototype Detector MOON-1 Hidehito NAKAMURA1� , Peter J. DOE2 , Hiroyasu EJIRI1;2;3 , Steven R. ELLIOTT2 scintillators is discussed as an option of the high-sensitivity detector MOON (Mo Observatory of Neutrinos

Engel, Jonathan

60

Prototype scintillator cell for an In-based solar neutrino detector  

NASA Astrophysics Data System (ADS)

We describe the work carried out at MPIK to design, model, build and characterize a prototype cell filled with a novel indium-loaded scintillator of interest for real-time low energy solar neutrino spectroscopy. First, light propagation in optical modules was studied with experiments and Monte Carlo simulations. Subsequently a 5 cm×5 cm×100 cm prototype detector was set-up and the optical performances of several samples were measured. We first tested a benchmark PXE-based scintillator, which performed an attenuation length of ˜4.2 m and a photo-electron yield of ˜730 pe/MeV. Then we measured three In-loaded samples. At an In-loading of 44 g/l, an energy resolution of ˜11.6% and a spatial resolution of ˜7 cm were attained for 477 keV recoil electrons. The long-range attenuation length in the cell was ˜1.3 m and the estimated photo-electron yield ˜200 pe/MeV. Light attenuation and relative light output of all tested samples could be reproduced reasonably well by MC. All optical properties of this system have remained stable over a period of >1 year.

Motta, D.; Buck, C.; Hartmann, F. X.; Lasserre, Th.; Schönert, S.; Schwan, U.

2005-08-01

61

A tracking detector based on capillaries with liquid scintillator  

NASA Astrophysics Data System (ADS)

A tracking detector with bundles of capillaries 20-25 ?m in diameter and 0.4 m long, filled with a liquid scintillator based on the methylnaphthalene with a new dye MBMP, exposed to the 70 GeV/ c P + beam has been studied. An attenuation length of 60-80 cm at distances L > 20 cm is obtained. Hit density on a track at a distance L = 155 mm is n = 4.4 mm -1 and n0 = 9.6 mm -1 at L = 0. A straight-line RMS residual is ?u ? 30 ?m, the two track resolution is ?u = 57 ?m. The light detected outside the track region (±3 ?u) is 14% of the total detected light.

Bozhko, N. I.; Elokhin, R. Yu.; Golovkin, S. V.; Gorin, A. M.; Korneev, S. A.; Kozarenko, E. N.; Kravzov, V. I.; Kushnirenko, A. E.; Medvedkov, A. M.; Peresypkin, A. I.; Petrenko, S. V.; Petukhov, Yu. P.; Tyukov, V. E.; Vasil'chenko, V. G.; Zaichenko, A. A.

1992-06-01

62

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

SciTech Connect

Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 x 1.5 and 2.0 x 2.0 mm{sup 2} cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be used 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.

Bircher, Chad; Shao Yiping [Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

2012-02-15

63

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

E-print Network

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.

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

2013-12-02

64

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

E-print Network

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...

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

2013-01-01

65

Two dimensional and linear scintillation detectors for fast neutron imaging — comparative analysis  

NASA Astrophysics Data System (ADS)

The paper was aimed to compare performance capabilities of two types of scintillation detectors commonly used for fast neutron imaging: two dimensional and linear ones. Best-case values of quantum efficiency, spatial resolution and capacity were estimated for detectors with plastic converter-screen in case of 14 MeV neutrons. For that there were examined nuclear reactions produced in converter-screen by fast neutrons, spatial distributions of energy release of emerged charged particles and amplitude distributions of scintillations generated by these particles. The paper shows that the efficiency of the linear detector is essentially higher and this detector provides potentially better spatial resolution in comparison with the two dimensional detector. But, the two dimensional detector surpasses the linear one in capacity. The presented results can be used for designing radiographic fast neutron detectors with organic scintillators.

Mikerov, V. I.; Koshelev, A. P.; Ozerov, O. V.; Sviridov, A. S.; Yurkov, D. I.

2014-05-01

66

Performance comparison of four compact room-temperature detectors-two cadmium zinc telluride (CZT) semiconductor detectors, a LaCl3(Ce) scintillator, and an NaI(Tl) scintillator  

Microsoft Academic Search

The performance characteristics of four compact, room-temperature detectors-two scintillators and two semiconductor detectors-were studied. All are commercially available detectors. The two scintillators were a o13 mm×13 mm lanthanum chloride [LaCl3(Ce)] detector and a o25 mm×25 mm sodium iodide [NaI(Tl)] detector. The two semiconductor detectors were a 10×10×3 mm3 cadmium zinc telluride (CZT) detector with a coplanar gridded anode and a

John K. Hartwell; Robert J. Gehrke; M. E. M. Ilwain

2005-01-01

67

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

DOEpatents

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.

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

1989-01-01

68

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

ERIC Educational Resources Information Center

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…

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

2012-01-01

69

Proton-induced radioactivity in NaI (Tl) scintillation detectors  

NASA Technical Reports Server (NTRS)

Radioactivity induced by protons in sodium iodide scintillation crystals were calculated and directly measured. These data are useful in determining trapped radiation and cosmic-ray induced, background-counting rates in spaceborne detectors.

Fishman, G. J.

1977-01-01

70

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

NASA Technical Reports Server (NTRS)

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.

Link, Jason

2011-01-01

71

Lithium glass scintillator neutron detector as an improved alternative to the standard 3 he proportional counter  

SciTech Connect

Lithium glass scintillator made from 6Li-enriched substrate is a well known for its neutron detection capability. In spite of neutron interaction, cross section of 6Li happens to be lower than that of 3He. However, the neutron detection efficiency could be higher due to higher volume content of 6Li nuclear in the solid scintillator vs. gas filled proportional counter. At the same time, as lithium glass is sensitive to gamma and charge particle radiation, non-neutron radiation discrimination is required. Our detector is composed of two equal-size cylindrical Li(Ce) glass scintillators. The first one is high-sensitive to thermal neutrons GS-20 (6Li doped), the second one is GS-30 (7Li doped) type Scint-Gobain made lithium glass scintillator. Each of scintillators is coupled with R7400U Hamamatsu subminiature photomultiplier tube, and all assembly is fitted into NP100H 3He tube size. 6Li absorbs thermal neutrons releasing alpha particles and triton with 4.8 MeV total energy deposit inside the scintillator (equivalent to about ~1.3 MeV gamma energy depositions). Because 7Li isotope does not absorb thermal neutrons, and the physical properties of the two scintillators are virtually identical, the difference between these two scintillators could be used to provide neutron dose rate information. Results of study of neutron detector assembled of two Li(Ce) scintillators and NP100H moderator are presented

Vladimir Popov, Pavel Degtiarenko

2011-06-01

72

Performance comparison of four compact room-temperature detectors - two cadmium zinc telluride (CZT) semiconductor detectors, a LaCl3(Ce) scintillator, and an NaI(Tl) scintillator  

Microsoft Academic Search

The performance characteristics of four compact, room-temperature detectors - two scintillators and two semiconductor detectors - were studied. All are commercially-available detectors. The two scintillators were a O13 mm × 13 mm lanthanum chloride [LaCl3(Ce)] detector and a O25 mm × 25 mm sodium iodide [NaI(Tl)] detector. The two semiconductor detectors were a 10 mm × 10 mm × 3

John K. Hartwell; Robert J. Gehrke; M. E. McIlwain

2004-01-01

73

Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations  

E-print Network

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.

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

2014-03-03

74

Impact of geometry on light collection efficiency of scintillation detectors for cryogenic rare event searches  

E-print Network

Simulations of photon propagation in scintillation detectors were performed with the aim to find the optimal scintillator geometry, surface treatment, and shape of external reflector in order to achieve maximum light collection efficiency for detector configurations that avoid direct optical coupling, a situation that is commonly found in cryogenic scintillating bolometers in experimental searches for double beta decay and dark matter. To evaluate the light collection efficiency of various geometrical configurations we used the ZEMAX ray-tracing software. It was found that scintillators in the shape of a triangular prism with an external mirror shaped as truncated cone gives the highest light collection efficiency. The results of the simulations were confirmed by carrying out measurements of the light collection efficiencies of CaWO4 crystal scintillators. A comparison of simulated and measured values of light output shows good agreement

F. A. Danevich; V. V. Kobychev; R. V. Kobychev; H. Kraus; V. B. Mikhailik; V. M. Mokina; I. M. Solsky

2014-04-30

75

Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations  

NASA Astrophysics Data System (ADS)

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 mm2. 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.

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

2014-02-01

76

Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations  

SciTech Connect

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.

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

77

Air gap effect on the properties of a long liquid scintillation detector  

NASA Astrophysics Data System (ADS)

Light attenuation, n-? pulse shape discrimination and timing properties of a long liquid scintillation detector (LLSD) were examined by means of Monte Carlo simulations and experiments. LLSD is a long rectangular shaped NE213 scintillator (80 × 6.5 × 10 cm 3) coupled with two photomultipliers and has been developed for neutron scattering experiments. We found that an air gap between a photomultiplier and a scintillator cell worked as a filter and reduced position dependencies of pulse height and of n-? pulse shape discrimination which were disadvantages on the use of LLSD, whereas it deteriorated n-? separation. This paper discusses the advantages and disadvantages of the air gap to the detector properties.

Matsuyama, S.; Soda, D.; Baba, M.; Iwasaki, S.; Ibaraki, M.; Ohkubo, T.; Nauchi, Y.; Hirakawa, N.

1997-02-01

78

Spatial response characterization of liquid scintillator detectors using collimated gamma-ray and neutron beams  

NASA Astrophysics Data System (ADS)

Liquid scintillators are suitable for many applications because they can detect and characterize fast neutrons as well as gamma-rays. This paper presents the response of a 15-cm-in-length×15-cm-in-height×8.2-cm-in-width EJ-309 liquid scintillator with respect to the position of neutron and gamma-ray interactions. Liquid scintillator cells are typically filled with 97% of the scintillating cocktail to address thermal expansion of the liquid in varying temperature conditions. Measurements were taken with collimated 137Cs and 252Cf sources for gamma-ray and neutron mapping of the detector, respectively. MCNPX-PoliMi (ver. 2.0) simulations were also performed to demonstrate the spatial response of the detector. Results show that the detector response is greatest at the center and decreases when the collimated neutron and gamma-ray beam is moved toward the edge of the detector. The measured response in the voxels surrounding the detector center decreased by approximately 6% and 12% for gamma-ray and neutron scans, respectively, when compared to the center voxel. The measured decrease in the detector response was most pronounced at the corners of detector assembly. For the corner voxels located in the bottom row of the detector, the measured response decreased by approximately 39% for both gamma-ray and neutron scans. For the corner voxels located in the top row of the detector, the measured response decreased by approximately 66% and 48% for gamma-ray and neutron scans, respectively. Both measurements and simulations show the inefficient production of secondary charged particles in the voxels located in the top portion of the detector due to the presence of expansion volume. Furthermore, the presence of the expansion volume potentially affects the transport of the scintillation light through the coupling window between the liquid scintillator and the photocathode in the photomultiplier tube.

Naeem, S. F.; Clarke, S. D.; Pozzi, S. A.

2013-10-01

79

Results from Noble Gas Scintillation Detectors with Solid State Light Readout  

NASA Astrophysics Data System (ADS)

A proof of concept is delivered regarding the performance and feasibility of using silicon photomultiplier (SiPM) solid state light readout devices in noble gas scintillation detectors. By immersing SiPMs directly in the scintillating gas, light collection values can be achieved that are highly competitive with those of PMT based detectors. The work further shows that pulse shape discrimination information is accessible even with the SiPM readout. This proof of concept opens the door for the design of highly rugged, low cost, high performance detectors.

Chandra, Rico; Davatz, Giovanna; Gendotti, Ulisse; Caccia, Massimo; Chmill, Valery; Martemiyanov, Sasha; Santoro, Romualdo

2014-02-01

80

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

E-print Network

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.

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

81

Novel radiation hard microfabricated scintillation detectors with high spatial resolution  

E-print Network

of a single channel with a serpentine geometry. The operation of such a device is very simple as it has only one inlet and one outlet. Once filled with liquid scintillator it comes to be a densely packed array

Dalang, Robert C.

82

Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency function.  

PubMed

In the paper, the SEM detector is evaluated by the modulation transfer function (MTF) which expresses the detector's influence on the SEM image contrast. This is a novel approach, since the MTF was used previously to describe only the area imaging detectors, or whole imaging systems. The measurement technique and calculation of the MTF for the SEM detector are presented. In addition, the measurement and calculation of the detective quantum efficiency (DQE) as a function of the spatial frequency for the SEM detector are described. In this technique, the time modulated e-beam is used in order to create well-defined input signal for the detector. The MTF and DQE measurements are demonstrated on the Everhart-Thornley scintillation detector. This detector was alternated using the YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators. The presented MTF and DQE characteristics show good imaging properties of the detectors with the YAP:Ce or CRY18 scintillator, especially for a specific type of the e-beam scan. The results demonstrate the great benefit of the description of SEM detectors using the MTF and DQE. In addition, point-by-point and continual-sweep e-beam scans in SEM were discussed and their influence on the image quality was revealed using the MTF. PMID:24323770

Bok, Jan; Schauer, Petr

2014-01-01

83

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

NASA Astrophysics Data System (ADS)

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.

Hartwig, Zachary S.; Gumplinger, Peter

2014-02-01

84

Development of a small scintillation detector with an optical fiber for fast neutrons.  

PubMed

To investigate the characteristics of a reactor and a neutron generator, a small scintillation detector with an optical fiber with ThO(2) has been developed to measure fast neutrons. However, experimental facilities where (232)Th can be used are limited by regulations, and S/N ratio is low because the background counts of this detector are increase by alpha decay of (232)Th. The purpose of this study is to develop a new optical fiber detector for measuring fast neutrons that does not use nuclear material such as (232)Th. From the measured and calculated results, the new optical fiber detector which uses ZnS(Ag) as a converter material together with a scintillator have the highest detection efficiency among several developed detectors. It is applied for the measurement of reaction rates generated from fast neutrons; furthermore, the absolute detection efficiency of this detector was obtained experimentally. PMID:21129989

Yagi, T; Unesaki, H; Misawa, T; Pyeon, C H; Shiroya, S; Matsumoto, T; Harano, H

2011-02-01

85

Sector-shaped fast organic liquid scintillation detectors based neutron coincidence counter.  

PubMed

A simulation based on the Monte Carlo method is described which has been performed using MCNPX 2.6.0, to model the geometry of a sector-shaped liquid scintillation detector in response to coincident neutron events. The detection of neutrons from a mixed-oxide (MOX) fuel pellet has been simulated for different thicknesses of scintillators. A layer of lead has been used to reduce the gamma-ray fluence reaching the scintillator and, the effect of lead for neutron detection has also been estimated by considering different thicknesses of lead layers. PMID:24972160

Gamage, K A A; Joyce, M J; Cave, F D

2014-09-01

86

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

SciTech Connect

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.

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

2008-05-12

87

Performance of the Liquid Xenon Scintillation Detector for the MEG Experiment  

Microsoft Academic Search

A large-volume liquid xenon (LXe) scintillation detector has been developed for the MEG experiment, which will seek evidence for the lepton flavor violating process, mu rarr egamma with a branching ratio sensitivity smaller than 10-13. A prototype detector with 100 L LXe was constructed to demonstrate that the performance of the proposed full-scale detector fulfills the requirements for the MEG

W. Ootani

2006-01-01

88

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

PubMed Central

Designing a plastic scintillation detector for proton radiation therapy requires careful consideration. Most plastic scintillators should not perturb a proton beam if they are sufficiently small but may exhibit some energy dependence due to quenching effect. In this work, we studied the factors that would affect the performance of such scintillation detectors. We performed Monte Carlo simulations of proton beams with energies between 50 and 250 MeV to study signal amplitude, water equivalence, spatial resolution, and quenching of light output. Implementation of the quenching effect in the Monte Carlo simulations was then compared with prior experimental data for validation. The signal amplitude of a plastic scintillating fiber detector was on the order of 300 photons per MeV of energy deposited in the detector, corresponding to a power of about 30 pW at a proton dose rate of 100 cGy/min. The signal amplitude could be increased by up to a factor of 2 with reflective coating. We also found that Cerenkov light was not a significant source of noise. Dose deposited in the plastic scintillator was within 2% of the dose deposited in a similar volume of water throughout the whole depth-dose curve for protons with energies higher than 50 MeV. A scintillation detector with a radius of 0.5 mm offers a sufficient spatial resolution for use with a proton beam of 100 MeV or more. The main disadvantage of plastic scintillators when irradiated by protons was the quenching effect, which reduced the amount of scintillation and resulted in dose underestimation by close to 30% at the Bragg peak for beams of 150 MeV or more. However, the level of quenching was nearly constant throughout the proximal half of the depth-dose curve for all proton energies considered. We therefore conclude that it is possible to construct an effective detector to overcome the problems traditionally encountered in proton dosimetry. Scintillation detectors could be used for surface or shallow measurements with a single calibration for a specific beam energy. For deeper measurements, Monte Carlo simulations can be used to generate depth-dependent correction factors. PMID:18364543

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

2014-01-01

89

Neutron response characterization for an EJ299-33 plastic scintillation detector  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

90

Multi-sector scintillation detector for investigations of extensive air showers  

NASA Astrophysics Data System (ADS)

A new type of scintillation detector for shower arrays is considered. The detector represents an octagonal scintillation assembly with total area 1 m 2 divided into sectors. Thickness of the plastic is 20 mm. The light is collected by wavelength shifter bars to the photomultiplier, which is located in the center of the detector. A solution to ensure the uniformity of light collection for any coordinate is proposed. Front-end electronics of the detector consists of the controller, the measuring part (QDC, TDC), the system of calibration and the HV converter. The data acquisition system is based on CAN-open standard. There is also a system of temperature stabilization that guarantees not more than 0.5° deviation of the temperature of measuring part elements. Measuring electronics allows obtaining the dynamic range from 1 up to 10 4 particles and 1 ns time digitization. The time resolution of the detector is about 3 ns.

Yanson, E. E.; Denisov, S. P.; Gilitsky, Yu. V.; Kindin, V. V.; Kokoulin, R. P.; Kompaniets, K. G.; Lipaev, V. V.; Matyushin, A. A.; Ovchinnikov, A. V.; Petrukhin, A. A.; Prokopenko, N. N.; Soldatov, M. M.; Sytin, A. N.

2009-01-01

91

Large-area imaging detector for neutron scattering based on boron-rich liquid scintillator  

NASA Astrophysics Data System (ADS)

We discuss a new thermal-neutron imaging detector that combines a neutron converter coupled to a position-sensitive gaseous photodetector. The neutron converter consists of a thin (0.5 mm) layer of boron-rich liquid scintillator. It is viewed by an atmospheric-pressure, gas-avalanche photomultiplier with a bialkali photocathode. Scintillation-induced photoelectrons are multiplied by a cascade of Gas Electron Multipliers (GEM). The multi-GEM supplies the pulse-height, time and position information for each converted neutron. Such a fast, large-area detector can operate at high radiation flux.

Vartsky, D.; Goldberg, M. B.; Breskin, A.; Chechik, R.; Guerard, B.; Clergeau, J. F.

2003-05-01

92

PoGOLino: A scintillator-based balloon-borne neutron detector  

NASA Astrophysics Data System (ADS)

PoGOLino is a balloon-borne scintillator-based experiment developed to study the largely unexplored high altitude neutron environment at high geomagnetic latitudes. The instrument comprises two detectors that make use of LiCAF, a novel neutron sensitive scintillator, sandwiched by BGO crystals for background reduction. The experiment was launched on March 20th 2013 from the Esrange Space Centre, Northern Sweden (geomagnetic latitude of 65°), for a three hour flight during which the instrument took data up to an altitude of 30.9 km. The detector design and ground calibration results are presented together with the measurement results from the balloon flight.

Kole, Merlin; Chauvin, Maxime; Fukazawa, Yasushi; Fukuda, Kentaro; Ishizu, Sumito; Jackson, Miranda; Kamae, Tune; Kawaguchi, Noriaki; Kawano, Takafumi; Kiss, Mózsi; Moretti, Elena; Pearce, Mark; Rydström, Stefan; Takahashi, Hiromitsu; Yanagida, Takayuki

2015-01-01

93

First-principles Electronic Structure Calculations for Scintillation Phosphor Nuclear Detector Materials  

NASA Astrophysics Data System (ADS)

Inorganic scintillation phosphors (scintillators) are extensively employed as radiation detector materials in many fields of applied and fundamental research such as medical imaging, high energy physics, astrophysics, oil exploration and nuclear materials detection for homeland security and other applications. The ideal scintillator for gamma ray detection must have exceptional performance in terms of stopping power, luminosity, proportionality, speed, and cost. Recently, trivalent lanthanide dopants such as Ce and Eu have received greater attention for fast and bright scintillators as the optical 5d to 4f transition is relatively fast. However, crystal growth and production costs remain challenging for these new materials so there is still a need for new higher performing scintillators that meet the needs of the different application areas. First principles calculations can provide a useful insight into the chemical and electronic properties of such materials and hence can aid in the search for better new scintillators. In the past there has been little first-principles work done on scintillator materials in part because it means modeling f electrons in lanthanides as well as complex excited state and scattering processes. In this talk I will give an overview of the scintillation process and show how first-principles calculations can be applied to such systems to gain a better understanding of the physics involved. I will also present work on a high-throughput first principles approach to select new scintillator materials for fabrication as well as present more detailed calculations to study trapping process etc. that can limit their brightness. This work in collaboration with experimental groups has lead to the discovery of some new bright scintillators.

Canning, Andrew

2013-03-01

94

Resolution and noise properties of scintillator coated X-ray detectors  

NASA Astrophysics Data System (ADS)

The imaging properties of X-ray pixel detectors depend on the quantum efficiency of X-rays, the generated signal of each X-ray photon and the distribution of the generated signal between pixels. In a scintillator coated device the signal is generated both by X-ray photons captured in the scintillator and by X-ray photons captured directly in the semiconductor. The Signal-to-Noise Ratio in the image is then a function of the number of photons captured in each of these processes and the yield, in terms of electron-hole pairs produced in the semiconductor, of each process. The spatial resolution is primarily determined by the light spreading within the scintillator. In a pure semiconductor detector the signal is generated by one process only. The Signal-to-Noise Ratio in the image is proportional to the number of X-ray photons captured within the sensitive layer. The spatial resolution is affected by the initial charge cloud generated in the semiconductor and any diffusion of carriers between the point of interaction and the readout electrode. In this paper we discuss the theory underlying the imaging properties of scintillator coated X-ray imaging detectors. The model is verified by simulations using MCNP and by experimental results. The results from the two-layer detector are compared with those from a pure semiconductor X-ray detector.

Dubaric, E.; Fröjdh, C.; Nilsson, H.-E.; Petersson, C. S.

2001-06-01

95

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

E-print Network

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.

M. Sorel

2014-09-05

96

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

NASA Astrophysics Data System (ADS)

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.

Runtso, Mikhail

97

Optimization of the scintillation detector in a combined 3D megavoltage CT scanner and portal imager.  

PubMed

A parametric study is described leading to the optimization of a custom-made scintillation detector with a relatively high quantum efficiency (QE) for megavoltage photons and light output toward a remote lens. This detector allows low-dose portal imaging and continuous cone-beam megavoltage CT acquisition. The EGS4 Monte Carlo code was used to simulate the x-ray and electron transport in the detector. A Monte Carlo model of optical photon transport in a detector element was devised and used as well as various irradiation experiments on scintillators. Different detector materials and configurations were compared in terms of the optical photon irradiance on the lens from on- and off-axis detector elements and the practical constraints regarding detector construction and weight. Effects of scintillator material, detector element size, crystal coating type, and reflectivity, combinations of different coatings on detector faces, scintillator doping level, and crystal transparency were studied. With scintillator thickness adjusted to give an 18% x-ray QE at 6 MV, the light output of CsI(Tl) was at least eight times higher than ZnWO4, BGO and NE118 plastic. Further, CsI(Tl) showed the smallest decrease in QE going from 6 to 24 MV. The off-axis reduction in emittance from the periphery of the detector was relatively small with a slight dependence on the type and reflectivity of the coating and the crystal thickness for a fixed detector element cross section. Light output was more strongly dependent on the reflectivity of lambertian coatings than specular ones. For a fixed detector element cross section, optimum coating type depended on crystal thickness. Typical CsI(Tl) crystals showed a relatively small variation in light output with changes in optical attenuation length. The optimum detector element was found to be CsI(Tl) coated on five faces with TiO2-loaded epoxy resin offering about a ten-fold improvement in light output per incident photon compared to typical metal/phosphor screens. PMID:9800695

Mosleh-Shirazi, M A; Swindell, W; Evans, P M

1998-10-01

98

Gamma-ray detector employing scintillators coupled to semiconductor drift photodetectors  

DOEpatents

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.

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

2003-01-01

99

High-sensitivity scintillating-fiber imaging detector for high-energy neutrons  

Microsoft Academic Search

We 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 cm2 array of plastic scintillating fibers. Each

D. Ress; R. A. Lerche; R. J. Ellis; G. W. Heaton; D. E. Lehr

1995-01-01

100

High-sensitivity scintillating-fiber imaging detector for high-energy neutrons  

Microsoft Academic Search

We 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 cm² array of plastic scintillating fibers. Each

D. Ress; R. A. Lerche; R. J. Ellis; G. W. Heaton; D. E. Lehr

1995-01-01

101

SNM detection by means of thermal neutron interrogation and a liquid scintillation detector  

NASA Astrophysics Data System (ADS)

The feasibility of using a pulsed neutron generator in a graphite assembly together with a single liquid scintillation detector for the detection of special nuclear materials is investigated. Thermal source neutrons induce fission in fissile material present in the sample. By means of pulse shape discrimination the detector signals from fast fission neutrons are easily identified among the signals from gamma rays and the interrogating thermal neutrons. The method has potential in applications for detection of special nuclear materials in shielded containers.

Ocherashvili, A.; Roesgen, E.; Beck, A.; Caspi, E. N.; Mosconi, M.; Crochemore, J.-M.; Pedersen, B.

2012-03-01

102

Development of a thermal neutron detector based on scintillating fibers and silicon photomultipliers.  

PubMed

We propose a technique for thermal neutron detection, based on a (6)Li converter placed in front of scintillating fibers readout by means of silicon photomultipliers. Such a technique allows building cheap and compact detectors and dosimeters, thus possibly opening new perspectives in terms of granular monitoring of neutron fluxes as well as space-resolved neutron detection. PMID:20886978

Barbagallo, Massimo; Cosentino, Luigi; Greco, Giuseppe; Montereali, Rosa Maria; Pappalardo, Alfio; Scirè, Carlotta; Scirè, Sergio; Vincenti, Maria Aurora; Finocchiaro, Paolo

2010-09-01

103

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

SciTech Connect

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.

S. Lami

2004-08-12

104

Probing the Earth's interior with a large-volume liquid scintillator detector  

E-print Network

A future large-volume liquid scintillator detector would provide a high-statistics measurement of terrestrial antineutrinos originating from $\\beta$-decays of the uranium and thorium chains. In addition, the forward displacement of the neutron in the detection reaction $\\bar\

Kathrin A. Hochmuth; Franz v. Feilitzsch; Brian D. Fields; Teresa Marrodan Undagoitia; Lothar Oberauer; Walter Potzel; Georg G. Raffelt; Michael Wurm

2005-09-13

105

Development of a thermal neutron detector based on scintillating fibers and silicon photomultipliers  

SciTech Connect

We propose a technique for thermal neutron detection, based on a {sup 6}Li converter placed in front of scintillating fibers readout by means of silicon photomultipliers. Such a technique allows building cheap and compact detectors and dosimeters, thus possibly opening new perspectives in terms of granular monitoring of neutron fluxes as well as space-resolved neutron detection.

Barbagallo, Massimo; Greco, Giuseppe; Scire, Carlotta; Scire, Sergio [INFN Laboratori Nazionali del Sud, via S. Sofia 62, 95125 Catania (Italy); Ansaldo Nucleare S.p.A., corso Perrone 25, 16161 Genova (Italy); Cosentino, Luigi; Pappalardo, Alfio; Finocchiaro, Paolo [INFN Laboratori Nazionali del Sud, via S. Sofia 62, 95125 Catania (Italy); Montereali, Rosa Maria; Vincenti, Maria Aurora [ENEA C.R. Frascati, Via Enrico Fermi, 45, 00044 Frascati, Roma (Italy)

2010-09-15

106

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

SciTech Connect

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.

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

107

Developments of a long liquid scintillation detector for fast neutron time-of-flight experiments  

NASA Astrophysics Data System (ADS)

We have developed a long NE213 liquid scintillation detector (LLSD, 80 cm × 6.5 cm × 10 cm) which is useful as a position sensitive detector and a high-efficiency neutron detector for measurements of neutron emission cross sections. LLSD is a long rectangular shaped NE213 scintillator coupled with two photomultipliers at both ends of the scintillator cell. Position information along the long cell axis is obtained by the time difference method. The time compensated signal needed for time-of-flight (TOF) experiments is provided by a mean timer. Data are acquired for TOF, position and pulse-height signals gated by n-? discriminator signals using a three-parameter data acquisition system. The updated data acquisition system and a position-dependent biasing analysis could achieve a remarkably lower bias level down to ˜1 MeV neutrons with good n-? discrimination compared to the similar type NE213 detectors and remove position dependence of detection efficiency. LLSD with the sophisticated data taking and processing techniques proved to be very effective for neutron emission cross section measurements for 10-18 MeV incident neutrons as a wide-angle scattering detector and a high-efficiency single detector.

Matsuyama, S.; Ohkubo, T.; Baba, M.; Iwasaki, S.; Soda, D.; Ibaraki, M.; Hirakawa, N.

1996-02-01

108

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

SciTech Connect

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.

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

109

Study of light transport inside scintillation crystals for PET detectors.  

PubMed

Scintillation crystal design is a critical component in positron emission tomography system development, which impacts a number of performance parameters including energy resolution, time resolution and spatial resolution. Our work aims to develop a generalized simulation tool to model the light transport inside scintillation crystals with good accuracy, taking into account surface treatments, reflectors, temporal dependence of scintillation decay, and comprehensive experimental validations. The simulation has been validated against both direct analytical calculation and experimental measurements. In this work, the studies were performed for a lutetium-yttrium oxyorthosilicate crystal of 3×3×20 mm(3) dimension coupled to a Hamamatsu silicon photomultiplier, with respect to light output, rise-time slope, energy resolution and time resolution. Four crystal surface treatment and reflector configurations were investigated: GroundMetal, GroundPaint, PolishMetal and PolishPaint. The experiments were performed to validate the Monte Carlo simulation results. The results indicate that the best time resolution (0.96±0.05 ns) and good energy resolution (10.6±0.4%) could be produced by using a polished surface with specular reflector, while the configuration of a polished surface with diffusive reflector produces the best energy resolution (10.2±0.9%). The results indicate that a polished surface with diffusive reflector achieves the best energy resolution (10.2±0.9%) for 511 keV high energy photons, and a polished surface with specular reflector achieves the best time resolution (0.96±0.05 ns) measured against a Hamamatsu fast photomultiplier tube. The ground surface treatment is not recommended for its inferior performance in terms of energy and time resolution. Possible explanations and future improvements to be made to the developed simulation tool are discussed. PMID:23470488

Yang, Xin; Downie, Evan; Farrell, Thomas; Peng, Hao

2013-04-01

110

Design of a high resolution positron emission tomograph using solid state scintillation detectors  

SciTech Connect

The authors propose a new concept of positron camera achieving nearly isotropic spatial resolution and uniform sensitivity throughout the useful field-of-view. The design is based on a quad scintillator dual channel detector module using two avalanche photodiodes as photodetectors. Original features include bilayered scintillators to measure the depth of interaction, tilted detectors relative to the radial direction to insure proper sampling in a stationary mode, multi-ring capability and independent acquisition channel for every discrete detector. Significantly better resolution is obtained towards the edges of the camera field and the sampling uniformity near the center is improved. Multi-ring systems with a slice thickness of 5 mm can be implemented to achieve true volume imaging with symmetrical 3-D spatial resolution. The performance of the proposed design is analyzed in terms of resolution, sensitivity, contrast and field uniformity.

Carrier, C.; Martel, C.; Schmitt, D.; Lecomte, R.

1988-02-01

111

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

SciTech Connect

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)

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

112

Timing resolution of scintillation-detector systems: a Monte Carlo analysis  

PubMed Central

Recent advancements in fast scintillating materials and fast photomultiplier tubes (PMTs) have stimulated renewed interest in time-of-flight (TOF) positron emission tomography (PET). It is well known that the improvement in the timing resolution in PET can significantly reduce the noise variance in the reconstructed image resulting in improved image quality. In order to evaluate the timing performance of scintillation detectors used in TOF PET, we use a Monte Carlo analysis to model the physical processes (crystal geometry, crystal surface finish, scintillator rise time, scintillator decay time, photoelectron yield, PMT transit time spread, PMT single-electron response, amplifier response, and time pick-off method) that can contribute to the timing resolution of scintillation-detector systems. In the Monte Carlo analysis, the photoelectron emissions are modeled by a rate function, which is used to generate the photoelectron time points. The rate function, which is simulated using Geant4, represents the combined intrinsic light emissions of the scintillator and the subsequent light transport through the crystal. The PMT output signal is determined by the superposition of the PMT single-electron response resulting from the photoelectron emissions. The transit time spread and the single-electron gain variation of the PMT are modeled in the analysis. Three practical time pick-off methods are considered in the analysis. Statistically, the best timing resolution is achieved with the first photoelectron timing. The calculated timing resolution suggests that a leading edge discriminator gives better timing performance than a constant fraction discriminator and produces comparable results when a 2-threshold or 3-threshold discriminator is used. For a typical PMT, the effect of detector noise on the timing resolution is negligible. The calculated timing resolution is found to improve with increasing mean photoelectron yield, decreasing scintillator decay time, and decreasing transit time spread. However, only substantial improvement in the timing resolution is obtained with improved transit time spread if the first photoelectron timing is less than the transit time spread. While the calculated timing performance does not seem to be affected by the pixel size of the crystal, it improves for an etched crystal compared to a polished crystal. In addition, the calculated timing resolution degrades with increasing crystal length. These observations can be explained by studying the initial photoelectron rate. Experimental measurements provide reasonably good agreement with the calculated timing resolution. The Monte Carlo analysis developed in this work will allow us to optimize the scintillation detectors for timing and to understand the physical factors limiting their performance. PMID:19820267

Choong, Woon-Seng

2010-01-01

113

Characteristics of a gamma-ray detector using a bismuth germanate scintillator  

NASA Astrophysics Data System (ADS)

Characteristics of a gamma-ray detector that utilizes a 24×24×15-mm3 bismuth germanate (BGO) scintillator are measured. Fluorescent light output measured with a BGO crystal coupled to a R1306 photomultiplier (Hamamatsu TV) is found to be 15% that of a NaI(T1) scintillator for incident photons of a given energy. The FWHM of the time spectrum, measured with two BGO crystals coupled to R329-2 photomultipliers, is equal to 2.0 ns for a 68Ge-68Ga source at room temperature.

Okajima, Kenichi; Takami, Katsumi; Ueda, Ken; Kawaguchi, Fumio

1982-08-01

114

Scintillation efficiency for low energy nuclear recoils in liquid xenon dark matter detectors  

NASA Astrophysics Data System (ADS)

We perform a theoretical study of the scintillation efficiency of the low energy region crucial for liquid xenon dark matter detectors. We develop a computer program to simulate the cascading process of the recoiling xenon nucleus in liquid xenon and calculate the nuclear quenching effect due to atomic collisions. We use the electronic stopping power extrapolated from experimental data to the low energy region, and take into account the effects of electron escape from electron-ion pair recombination using the generalized Thomas-Imel model fitted to scintillation data. Our result agrees well with the experiments from neutron scattering and vanishes rapidly as the recoil energy drops below 3 keV.

Mu, Wei; Xiong, Xiaonu; Ji, Xiangdong

2015-02-01

115

Improved Growth Methods for LaBr3 Scintillation Radiation Detectors  

SciTech Connect

The objective is to develop advanced materials for deployment as high-resolution gamma ray detectors. Both LaBr3 and CeBr3 are advanced scintillation materials, and will be studied in this research. Prototype devices, in collaboration Sandia National Laboratories, will be demonstrated along with recommendations for mass production and deployment. It is anticipated that improved methods of crystal growth will yield larger single crystals of LaBr3 for deployable room-temperature operated gamma radiation spectrometers. The growth methods will be characterized. The LaBr3 and CeBr3 scintillation crystals will be characterized for light yield, spectral resolution, and for hardness.

Douglas S. McGregor

2011-05-01

116

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

PubMed

The goal of this work was to demonstrate the feasibility of using a plastic scintillation detector (PSD) incorporated into a prostate immobilization device to verify doses in vivo delivered during intensity-modulated radiation therapy (IMRT) and volumetric modulated-arc therapy (VMAT) for prostate cancer. The treatment plans for both modalities had been developed for a patient undergoing prostate radiation therapy. First, a study was performed to test the dependence, if any, of PSD accuracy on the number and type of calibration conditions. This study included PSD measurements of each treatment plan being delivered under quality assurance (QA) conditions using a rigid QA phantom. PSD results obtained under these conditions were compared to ionization chamber measurements. After an optimal set of calibration factors had been found, the PSD was combined with a commercial endorectal balloon used for rectal distension and prostate immobilization during external beam radiotherapy. This PSD-enhanced endorectal balloon was placed inside of a deformable anthropomorphic phantom designed to simulate male pelvic anatomy. PSD results obtained under these so-called "simulated treatment conditions" were compared to doses calculated by the treatment planning system (TPS). With the PSD still inserted in the pelvic phantom, each plan was delivered once again after applying a shift of 1 cm anterior to the original isocenter to simulate a treatment setup error.The mean total accumulated dose measured using the PSD differed the TPS-calculated doses by less than 1% for both treatment modalities simulated treatment conditions using the pelvic phantom. When the isocenter was shifted, the PSD results differed from the TPS calculations of mean dose by 1.2% (for IMRT) and 10.1% (for VMAT); in both cases, the doses were within the dose range calculated over the detector volume for these regions of steep dose gradient. Our results suggest that the system could benefit prostate cancer patient treatment by providing accurate in vivo dose reports during treatment and verify in real-time whether treatments are being delivered according to the prescribed plan. PMID:23180976

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

2012-10-01

117

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

PubMed Central

The goal of this work was to demonstrate the feasibility of using a plastic scintillation detector (PSD) incorporated into a prostate immobilization device to verify doses in vivo delivered during intensity-modulated radiation therapy (IMRT) and volumetric modulated-arc therapy (VMAT) for prostate cancer. The treatment plans for both modalities had been developed for a patient undergoing prostate radiation therapy. First, a study was performed to test the dependence, if any, of PSD accuracy on the number and type of calibration conditions. This study included PSD measurements of each treatment plan being delivered under quality assurance (QA) conditions using a rigid QA phantom. PSD results obtained under these conditions were compared to ionization chamber measurements. After an optimal set of calibration factors had been found, the PSD was combined with a commercial endorectal balloon used for rectal distension and prostate immobilization during external beam radiotherapy. This PSD-enhanced endorectal balloon was placed inside of a deformable anthropomorphic phantom designed to simulate male pelvic anatomy. PSD results obtained under these so-called “simulated treatment conditions” were compared to doses calculated by the treatment planning system (TPS). With the PSD still inserted in the pelvic phantom, each plan was delivered once again after applying a shift of 1 cm anterior to the original isocenter to simulate a treatment setup error. The mean total accumulated dose measured using the PSD differed the TPS-calculated doses by less than 1% for both treatment modalities simulated treatment conditions using the pelvic phantom. When the isocenter was shifted, the PSD results differed from the TPS calculations of mean dose by 1.2% (for IMRT) and 10.1% (for VMAT); in both cases, the doses were within the dose range calculated over the detector volume for these regions of steep dose gradient. Our results suggest that the system could benefit prostate cancer patient treatment by providing accurate in vivo dose reports during treatment and verify in real-time whether treatments are being delivered according to the prescribed plan. PMID:23180976

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

2012-01-01

118

Fast Neutron Detector for Fusion Reactor KSTAR Using Stilbene Scintillator  

E-print Network

Various neutron diagnostic tools are used in fusion reactors to evaluate different aspects of plasma performance, such as fusion power, power density, ion temperature, fast ion energy, and their spatial distributions. The stilbene scintillator has been proposed for use as a neutron diagnostic system to measure the characteristics of neutrons from the Korea Superconducting Tokamak Advanced Research (KSTAR) fusion reactor. Specially designed electronics are necessary to measure fast neutron spectra with high radiation from a gamma-ray background. The signals from neutrons and gamma-rays are discriminated by the digital charge pulse shape discrimination (PSD) method, which uses total to partial charge ratio analysis. The signals are digitized by a flash analog-to-digital convertor (FADC). To evaluate the performance of the fabricated stilbene neutron diagnostic system, the efficiency of 10 mm soft-iron magnetic shielding and the detection efficiency of fast neutrons were tested experimentally using a 252Cf neutr...

Lee, Seung Kyu; Kim, Gi-Dong; Kim, Yong-Kyun

2011-01-01

119

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

PubMed

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

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

2009-07-01

120

Evaluation of Large Volume SrI2(Eu) Scintillator Detectors  

SciTech Connect

There is an ever increasing demand for gamma-ray detectors which can achieve good energy resolution, high detection efficiency, and room-temperature operation. We are working to address each of these requirements through the development of large volume SrI2(Eu) scintillator detectors. In this work, we have evaluated a variety of SrI2 crystals with volumes >10 cm3. The goal of this research was to examine the causes of energy resolution degradation for larger detectors and to determine what can be done to mitigate these effects. Testing both packaged and unpackaged detectors, we have consistently achieved better resolution with the packaged detectors. Using a collimated gamma-ray source, it was determined that better energy resolution for the packaged detectors is correlated with better light collection uniformity. A number of packaged detectors were fabricated and tested and the best spectroscopic performance was achieved for a 3% Eu doped crystal with an energy resolution of 2.93% FWHM at 662keV. Simulations of SrI2(Eu) crystals were also performed to better understand the light transport physics in scintillators and are reported. This study has important implications for the development

Sturm, Benjamin [Lawrence Livermore National Laboratory (LLNL); Cherepy, Nerine [Lawrence Livermore National Laboratory (LLNL); Drury, Owen [Lawrence Livermore National Laboratory (LLNL); Thelin, P [Lawrence Livermore National Laboratory (LLNL); Fisher, S E [Lawrence Livermore National Laboratory (LLNL); Magyar, Albert [Lawrence Livermore National Laboratory (LLNL); Payne, Stephen A. [Lawrence Livermore National Laboratory (LLNL); Burger, Arnold [Fisk University, Nashville, TN; Boatner, Lynn A [ORNL; Ramey, Joanne Oxendine [ORNL; Shah, Kanai [Radiation Monitoring Devices, Watertown, MA; Hawrami, Rastgo [Radiation Monitoring Devices, Watertown, MA

2010-01-01

121

Impact of fano factor on position and energy estimation in scintillation detectors  

NASA Astrophysics Data System (ADS)

The Fano factor for an integer-valued random variable is defined as the ratio of its variance to its mean. Light from various scintillation crystals has been reported to have Fano factors from sub-Poisson (Fano factor < 1), Poisson (Fano factor = 1) to super-Poisson (Fano factor > 1). For a given mean, a smaller Fano factor implies a smaller variance and thus less noise. We investigate if lower noise in the scintillation light results in better spatial and energy resolution in a scintillation imaging detector. The impact of Fano factor on estimation of position of interaction and energy deposited in simple gamma-camera geometries is estimated by calculating the Cramer-Rao bound. The calculated Cramer-Rao bound is quantitatively validated by estimating the variance of the maximum likelihood estimator.

Bora, Vaibhav; Barrett, Harrison H.; Jha, Abhinav K.; Clarkson, Eric

2013-09-01

122

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

SciTech Connect

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.

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

123

Organic scintillation detector response simulation using non-analog MCNPX-PoliMi  

SciTech Connect

Organic liquid scintillation detectors are valuable for the detection of special nuclear material since they are capable of detecting both neutrons and gamma rays. Scintillators can also provide energy information which is helpful in identification and characterization of the source. In order to design scintillation based measurement systems appropriate simulation tools are needed. MCNPX-PoliMi is capable of simulating scintillation detector response; however, simulations have traditionally been run in analog mode which leads to long computation times. In this paper, non-analog MCNPX-PoliMi mode which uses variance reduction techniques is applied and tested. The non-analog MCNPX-PoliMi simulation test cases use source biasing, geometry splitting and a combination of both variance reduction techniques to efficiently simulate pulse height distribution and then time-of-flight for a heavily shielded case with a {sup 252}Cf source. An improvement factor (I), is calculated for distributions in each of the three cases above to analyze the effectiveness of the non-analog MCNPX-PoliMi simulations in reducing computation time. It is found that of the three cases, the last case which uses a combination of source biasing and geometry splitting shows the most improvement in simulation run time for the same desired variance. For pulse height distributions speedup ranging from a factor 5 to 25 is observed, while for time-of-flights the speedup factors range from 3 to 10. (authors)

Prasad, S.; Clarke, S. D.; Pozzi, S. A.; Larsen, E. W. [Univ. of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48109 (United States)

2012-07-01

124

Reflection properties of scintillator-septum candidates for a pixelated MeV detector  

NASA Astrophysics Data System (ADS)

In order to predict and improve the performance of pixelated detectors, it is important to understand the optical properties of the basic unit of the scintillating structure in the detector. To measure one of the essential optical properties, reflectance, we have used a device composed of a laser and photodiode array. We have also developed an analytical model of the optical phenomena based on Snell's law and the Fresnel equations to simply analyze measured results and reflectance parameters at the interface. The computed and experimentally measured results typically have good agreement, validating the analytical model and measurements. The optical parameters are used as inputs to GEANT4 [1]. The simulations are then leveraged to optimize an imager design before a prototype is built. The optical reflectance was measured by using relatively inexpensive samples. A sample has scintillator, glue, and septum (reflector) layers, and each sample has a different scintillator surface (polished/rough) and/or reflector [ESR film/aluminum-sputtered (coated) ESR film] condition. A high-refractive-index hemisphere was attached on the top surface of a sample to increase the maximum incidence angle at the scintillator-glue interface from 27° to 52°. The sample including ESR film demonstrated average reflectance approximately 1.3 times higher than that from the sample with aluminum-sputtered ESR film as a reflector, and the polished surface condition showed higher reflectance than the rough-cut surface condition.

Shin, Mihye; Star-Lack, Josh; Janecek, Martin; Abel, Eric; Shedlock, Daniel; Fahrig, Rebecca

2014-03-01

125

Characteristics of Un doped and Europium-dopedSrI2 Scintillator Detectors  

SciTech Connect

High energy resolution gamma-ray detectors that can be formed into relatively large sizes while operating at room temperature offer many advantages for national security applications. We are working toward that goal through the development of SrI{sub 2}(Eu) scintillator detectors, which routinely provide <;3.0% energy resolution at 662 keV with volumes >;10 cm{sup 3}. In this study, we have tested pure, undoped SrI{sub 2} to gain a better understanding of the scintillation properties and spectroscopic performance achievable without activation. An undoped crystal grown from 99.999% pure SrI{sub 2} pellets was tested for its spectroscopic performance, its light yield, and uniformity of scintillation light collection as a function of gamma-ray interaction position relative to the crystal growth direction. Undoped SrI{sub 2} was found to provide energy resolution of 5.3% at 662 keV, and the light collection nonuniformity varied by only 0.72% over the length of the crystal. Measurements of both a 3% Eu-doped and the undoped SrI{sub 2} crystal were carried out in the SLYNCI facility and indicate differences in their light yield non-proportionality. The surprisingly good scintillation properties of the pure SrI{sub 2} crystal suggests that with high-purity feedstock, further reduction of the Eu concentration can be made to grow larger crystals while not adversely impacting the spectroscopic performance.

Sturm, Benjamin [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Cherepy, Nerine [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Drury, Owen [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Thelin, P [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Fisher, S E [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); O’Neal, S P [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Payne, Stephen A. [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Burger, Arnold [Fisk University, Nashville, TN] [Fisk University, Nashville, TN; Boatner, Lynn A [ORNL] [ORNL; Ramey, Joanne Oxendine [ORNL] [ORNL; Shah, Kanai [Radiation Monitoring Devices, Watertown, MA] [Radiation Monitoring Devices, Watertown, MA; Hawrami, Rastgo [Fisk University, Nashville, TN] [Fisk University, Nashville, TN

2012-01-01

126

Fast Neutron Detector for Fusion Reactor KSTAR Using Stilbene Scintillator  

E-print Network

Various neutron diagnostic tools are used in fusion reactors to evaluate different aspects of plasma performance, such as fusion power, power density, ion temperature, fast ion energy, and their spatial distributions. The stilbene scintillator has been proposed for use as a neutron diagnostic system to measure the characteristics of neutrons from the Korea Superconducting Tokamak Advanced Research (KSTAR) fusion reactor. Specially designed electronics are necessary to measure fast neutron spectra with high radiation from a gamma-ray background. The signals from neutrons and gamma-rays are discriminated by the digital charge pulse shape discrimination (PSD) method, which uses total to partial charge ratio analysis. The signals are digitized by a flash analog-to-digital convertor (FADC). To evaluate the performance of the fabricated stilbene neutron diagnostic system, the efficiency of 10 mm soft-iron magnetic shielding and the detection efficiency of fast neutrons were tested experimentally using a 252Cf neutron source. In the results, the designed and fabricated stilbene neutron diagnostic system performed well in discriminating neutrons from gamma-rays under the high magnetic field conditions during KSTAR operation. Fast neutrons of 2.45 MeV were effectively measured and evaluated during the 2011 KSTAR campaign.

Seung Kyu Lee; Byoung-Hwi Kang; Gi-Dong Kim; Yong-Kyun Kim

2011-12-27

127

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

NASA Astrophysics Data System (ADS)

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.

Prasad, Shikha

128

Neutron-sensing scintillating glass optical fiber detectors  

SciTech Connect

Pacific Northwest Laboratory (PNL) has developed and tested the highest-transmission neutron-sensing glass fibers reported in the open literature to date. By developing glass compositions specifically for fiber drawing and by using superior oxidationstate controls and rapid quenching, PNL produces, fiber with useful lengths in excess of 200 cm. These long fibers can be used in detectors. Test results on the fibers used as a form-fitting detector around a small storage container containing neutron and gamma ray sources are reported. Excellent neutron-gamma ray discrimination has been achieved. These neutron-sensing glass optical fibers provide for new methods for monitoring the inventory of, preventing the diversion of, and detecting the unauthorized transport of sensitive nuclear materials. As such, it represents a significant potential element in countering the threat of nuclear terrorism.

Bliss, M.; Reeder, P.L.; Craig, R.A.

1994-07-01

129

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

Microsoft Academic Search

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

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

130

Calorimeter prototype based on silicon drift detectors coupled to scintillators for Compton telescopes application  

Microsoft Academic Search

The project of a new calorimeter module for Compton telescopes based on an array of silicon drift detectors (SDD) coupled to thallium activated cesium iodide (CsI(Tl)) scintillating crystals is presented. Because of their low output capacitance and the possibility to have the first amplifying stage directly integrated on chip, SDDs show better noise performances than traditional p-intrinsic-n (PIN) photodiodes. For

M. Marisaldi; C. Labanti; A. Bulgarelli; E. Celesti; G. Di Cocco; F. Gianotti; A. Mauri; E. Rossi; A. Traci; M. Trifoglio

2004-01-01

131

Searching for Dark Matter Annihilation to Monoenergetic Neutrinos with Liquid Scintillation Detectors  

E-print Network

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 the best sensitivity to such models for $m_X \\lesssim 14$ GeV.

Kumar, Jason

2015-01-01

132

A gain monitoring system for scintillation detectors using ultra bright LEDs  

Microsoft Academic Search

A gain monitoring system based on ultra bright LEDs was developed for the scintillation counters of the PiP\\/TOF detectors to be employed in (?, NN) experiments at the 855 MeV microtron MAMI-B in Mainz. The intensive light pulses of one LED supplied 16 photomultipliers simultaneously and one PIN diode for monitoring. The stability of the corrected photomultiplier gain is better

T. Hehl; P. Grabmayr; M. Sauer; G. J. Wagner

1995-01-01

133

Advances in CMOS solid-state photomultipliers for scintillation detector applications  

Microsoft Academic Search

Solid-state photomultipliers (SSPMs) are a compact, lightweight, potentially low-cost alternative to a photomultiplier tube for a variety of scintillation detector applications, including digital-dosimeter and medical-imaging applications. Manufacturing SSPMs with a commercial CMOS process provides the ability for rapid prototyping, and facilitates production to reduce the cost. RMD designs CMOS SSPM devices that are fabricated by commercial foundries. This work describes

James F. Christian; Christopher J. Stapels; Erik B. Johnson; Mickel McClish; Purushotthom Dokhale; Kanai S. Shah; Sharmistha Mukhopadhyay; Eric Chapman; Frank L. Augustine

2010-01-01

134

Advances in CMOS Solid-state Photomultipliers for Scintillation Detector Applications  

PubMed Central

Solid-state photomultipliers (SSPMs) are a compact, lightweight, potentially low-cost alternative to a photomultiplier tube for a variety of scintillation detector applications, including digital-dosimeter and medical-imaging applications. Manufacturing SSPMs with a commercial CMOS process provides the ability for rapid prototyping, and facilitates production to reduce the cost. RMD designs CMOS SSPM devices that are fabricated by commercial foundries. This work describes the characterization and performance of these devices for scintillation detector applications. This work also describes the terms contributing to device noise in terms of the excess noise of the SSPM, the binomial statistics governing the number of pixels triggered by a scintillation event, and the background, or thermal, count rate. The fluctuations associated with these terms limit the resolution of the signal pulse amplitude. We explore the use of pixel-level signal conditioning, and characterize the performance of a prototype SSPM device that preserves the digital nature of the signal. In addition, we explore designs of position-sensitive SSPM detectors for medical imaging applications, and characterize their performance.

Christian, James F.; Stapels, Christopher J.; Johnson, Erik B.; McClish, Mickel; Dokhale, Purushotthom; Shah, Kanai S.; Mukhopadhyay, Sharmistha; Chapman, Eric; Augustine, Frank L.

2014-01-01

135

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

SciTech Connect

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)].

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

136

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

PubMed

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)]. PMID:19499603

García-Muñoz, M; Fahrbach, H-U; Zohm, H

2009-05-01

137

High resolution tracking detector based on capillaries with a liquid scintillator  

NASA Astrophysics Data System (ADS)

A tracking detector with a capillary bundle filled with a liquid scintillator exposed to a 40 GeV ? beam has been investigated. Image intensifiers have been used to amplify optical signals from the detector. The information was read out by a CCD. The obtained number of hits per unit track length n0 was 13 mm -1 with a straight-line RMS residual ?tr=43 ?m. The track impact parameter precision was ? ? 7 ?m. The two-track resolution was 100 ?m.

Denisov, A. G.; Golovkin, S. V.; Gorin, A. M.; Kozarenko, E. N.; Kushnirenko, A. E.; Medvedkov, A. M.; Peresypkin, A. I.; Petrenko, S. V.; Petukhov, Yu. P.; Rykalin, V. I.; Tyukov, V. E.; Vasil'chenko, V. G.; Zaichenko, A. A.

1991-12-01

138

Development of a scintillation detector using a MPPC as an alternative to an APD  

NASA Astrophysics Data System (ADS)

We conducted a study to examine the performance of the multi-pixel photon counter(MPPC). The MPPC is a novel type of semiconductor photodetector consisting of multiple avalanche photodiode (APD) pixels operated in Geiger mode. Whereas the MPPC offers a great advantage in signal multiplication comparable to that achieved by the photomultiplier tube (PMT), the detection of weak scintillation light signals is difficult due to the severe contamination of dark counts. In this study, we first compared the energy resolutions and energy thresholds of a 3 × 3 mm2 MPPC with those of a 3 × 3 mm2 APD as scintillation detectors. The MPPC and APD were optically coupled with 5 × 5 × 5 mm3 scintillation crystals of BGO, Tl:CsI, Pr:LuAG, and YAG. It turned out that the APD had better energy resolutions for 662 keV gamma-rays, while the MPPC had lower energy thresholds as measured using a test pulse. Despite the low energy thresholds, it is difficult for the MPPC to detect low energy gamma-rays due to the contamination of dark counts. Secondly, we applied a coincidence technique to discriminate weak gamma-ray signals from dark counts by using scintillation detectors that consisted of a 2 × 2 MPPC-array optically coupled with 10 × 10 × 10 mm3 crystals of GSO, BGO, and Pr:LuAG. With this technique, we demonstrated that dark counts achieved a rejection efficiency of more than 99.8%. As a result, 22.2 keV gamma-rays were successfully detected with a GSO scintillator as measured at +20°C.

Miura, T.; Nakamori, T.; Kataoka, J.; Kato, T.; Sato, K.; Ishikawa, Y.; Yamamura, K.; Kawabata, N.

2012-02-01

139

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

SciTech Connect

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.

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

140

Identification of prompt fission ?-rays with lanthanum-chloride scintillation detectors  

NASA Astrophysics Data System (ADS)

In this paper we demonstrate the employment of LaCl3:Ce scintillation detectors for the identification of prompt fission ?-rays from ?-radiation in contrast to other reactions. We present the properties of cylindrical 1.5 in.×1.5 in. detectors in terms of intrinsic activity, energy resolution, intrinsic full peak efficiency and intrinsic timing resolution. In addition, we show results from the measurement of ?-rays emitted in coincidence with the spontaneous fission of 252Cf, which lead us to the conclusion that the properties of the detectors used in this work, in particular the good timing resolution and a reasonably good energy resolution, are more than just sufficient for the assessment of prompt ?-heat in future nuclear reactors as requested by the OECD. Hence, in our opinion, LaCl3:Ce detectors, compared to those made out of LaBr3:Ce crystals, represent an appropriate and quasi low-cost choice for the above mentioned applications.

Oberstedt, A.; Oberstedt, S.; Billnert, R.; Geerts, W.; Hambsch, F.-J.; Karlsson, J.

2012-03-01

141

Development of a directional scintillating fiber detector for 14 MeV neutrons  

NASA Astrophysics Data System (ADS)

We have developed a directional detector for 14 MeV neutrons. The detector consists of an 8×8 array of plastic scintillating fibers coupled to a multi-anode photomultiplier tube. Protons in the fibers are scattered by incident neutrons and are detected as they pass through multiple fibers. The direction of the flux of incident neutrons is determined using the energy and direction of the recoil proton. The advantages of the detector are its small size and ability to detect fast neutrons. We used GEANT4 to simulate the detector performance, and report the results of experimental studies with neutrons from a 14 MeV pulsed D-T neutron generator.

Peel, Justin; Mascarenhas, Nicholas; Mengesha, Wondwosen; Sunnarborg, Duane

2006-01-01

142

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

SciTech Connect

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.

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

143

Simple algorithms for digital pulse-shape discrimination with liquid scintillation detectors  

NASA Astrophysics Data System (ADS)

The development of compact, battery-powered digital liquid scintillation neutron detection systems for field applications requires digital pulse processing (DPP) algorithms with minimum computational overhead. To meet this demand, two DPP algorithms for the discrimination of neutron and ?-rays with liquid scintillation detectors were developed and examined by using a NE213 liquid scintillation detector in a mixed radiation field. The first algorithm is based on the relation between the amplitude of a current pulse at the output of a photomultiplier tube and the amount of charge contained in the pulse. A figure-of-merit (FOM) value of 0.98 with 450 keVee (electron equivalent energy) energy threshold was achieved with this method when pulses were sampled at 250 MSample/s and with 8-bit resolution. Compared to the similar method of charge-comparison this method requires only a single integration window, thereby reducing the amount of computations by approximately 40%. The second approach is a digital version of the trailing-edge constant-fraction discrimination method. A FOM value of 0.84 with an energy threshold of 450 keVee was achieved with this method. In comparison with the similar method of rise-time discrimination this method requires a single time pick-off, thereby reducing the amount of computations by approximately 50%. The algorithms described in this work are useful for developing portable detection systems for applications such as homeland security, radiation dosimetry and environmental monitoring.

Alharbi, T.

2015-01-01

144

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

PubMed

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

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

2013-07-01

145

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

146

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

NASA Astrophysics Data System (ADS)

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.

Sherman, Keegan; Gilfoyle, Gerard

2012-10-01

147

Investigation of three-dimensional localisation of radioactive sources using a fast organic liquid scintillator detector  

NASA Astrophysics Data System (ADS)

In this paper we discuss the possibility of locating radioactive sources in space using a scanning-based method, relative to the three-dimensional location of the detector. The scanning system comprises an organic liquid scintillator detector, a tungsten collimator and an adjustable equatorial mount. The detector output is connected to a bespoke fast digitiser (Hybrid Instruments Ltd., UK) which streams digital samples to a personal computer. A radioactive source has been attached to a vertical wall and the data have been collected in two stages. In the first case, the scanning system was placed a couple of metres away from the wall and in the second case it moved few centimetres from the previous location, parallel to the wall. In each case data were collected from a grid of measurement points (set of azimuth angles for set of elevation angles) which covered the source on the wall. The discrimination of fast neutrons and gamma rays, detected by the organic liquid scintillator detector, is carried out on the basis of pulse gradient analysis. Images are then produced in terms of the angular distribution of events for total counts, gamma rays and neutrons for both cases. The three-dimensional location of the neutron source can be obtained by considering the relative separation of the centres of the corresponding images of angular distribution of events. The measurements have been made at the National Physical Laboratory, Teddington, Middlesex, UK.

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

2013-04-01

148

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

PubMed

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

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

2015-02-01

149

Passively scattered proton beam entrance dosimetry with a plastic scintillation detector  

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

150

The prompt response of bismuth germanate and NaI(Tl) scintillation detectors to fast neutrons  

NASA Astrophysics Data System (ADS)

Spectral distribution and yields of scintillation pulses from the prompt interaction of neutrons with 7.6 cm diameter × 7.6 cm long bismuth germanate (BGO) and NaI(Tl) detectors have been measured. Neutrons at energies between 0.4 and 10 MeV were produced by the 7Li(p, n) and the 197Au(p, n) reactions, respectively, and identified by their time-of-flight relative to the pulsed proton beam. For both scintillators the neutron response is dominated by (n, n'?) reactions, and the efficiencies are in qualitative agreement with simple estimates that depend on the non-elastic and elastic cross sections, and on two geometrical factors. Compared to NaI(Tl), BGO exhibits a much superior gamma-ray-to-neutron detection ratio.

Häusser, O.; Lone, M. A.; Alexander, T. K.; Kushneriuk, S. A.; Gascon, J.

1983-08-01

151

Scalability, scintillation readout and charge drift in a kilogram scale solid xenon particle detector  

E-print Network

We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employ a liquid nitrogen cooled cryostat combined with a xenon purification and chiller system to measure the scintillation light output and electron drift speed from both the solid and liquid phases of xenon. Scintillation light output from sealed radioactive sources is measured by a set of high quantum efficiency photomultiplier tubes suitable for cryogenic applications. We observed a reduced amount of photons in solid phase compared to that in liquid phase. We used a conventional time projection chamber system to measure the electron drift time in a kilogram of solid xenon and observed faster electron drift speed in the solid phase xenon compared to that in the liquid phase.

Yoo, J; Jaskierny, W F; Markley, D; Pahlka, R B; Balakishiyeva, D; Saab, T; Filipenko, M

2014-01-01

152

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

SciTech Connect

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.

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

153

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

NASA Astrophysics Data System (ADS)

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 simulation code, MCNPX, has been used to analyze spectral distribution available from the plastic detector and to derive algorithmic process with a view to discriminating targeted sources from ambient background radiation. Theoretical results in present work showed that the targeted sources which might be used for nuclear/radiological terrorism could be discriminated from Nationally Occurring Radioactive Material (NORM) or background.

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

2009-06-01

154

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

PubMed

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

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

2013-07-01

155

Fission signal detection using helium-4 gas fast neutron scintillation detectors  

NASA Astrophysics Data System (ADS)

We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure 4He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the 4He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

Lewis, J. M.; Kelley, R. P.; Murer, D.; Jordan, K. A.

2014-07-01

156

Fission signal detection using helium-4 gas fast neutron scintillation detectors  

SciTech Connect

We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure {sup 4}He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the {sup 4}He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

Lewis, J. M., E-mail: lewisj@ufl.edu; Kelley, R. P.; Jordan, K. A. [Nuclear Engineering Program, University of Florida, Gainesville, Florida 32611 (United States); Murer, D. [Arktis Radiation Detectors Ltd., 8045 Zurich (Switzerland)

2014-07-07

157

Development of scintillating fiber detector technology for high rate particle tracking  

E-print Network

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.

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

1997-10-02

158

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

PubMed

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. PMID:22559526

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

2012-04-01

159

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

SciTech Connect

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.

Mohanty, P. K.; Dugad, S. R.; Gupta, S. K. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India)

2012-04-15

160

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

161

Development of a new neutron monitor using a boron-loaded organic liquid scintillation detector  

NASA Astrophysics Data System (ADS)

A new type of neutron dose monitor was developed by using a 12.7 cm diameter×12.7 cm long boron-loaded organic liquid scintillation detector BC523A. This detector aims to have a response in the wide energy range of thermal energy to 100 MeV by using the H and C reactions to the fast neutrons of organic liquid and the 10B(n, ?) reaction to thermalized neutrons in the liquid. The response functions of this detector were determined by the Monte Carlo simulation in the energy region from thermal energy to 100 MeV. Using these response functions, the spectrum-weighted dose function, G-function, to get the neutron dose from the light output spectrum of the detector was also determined by the unfolding technique. The calculated G-function was applied to determine the neutron dose in real neutron fields having energies ranging from thermal energy to several tens of MeV, where the light output spectra were measured with the BC523A detector. The thus-obtained ambient doses and effective doses show rather good agreement with the fluence-to-dose conversion factor given by ICRP 74. This detector will be useful as a wide-energy range neutron monitor.

Rasolonjatovo, A. H. D.; Shiomi, T.; Kim, E.; Nakamura, T.; Nunomiya, T.; Endo, A.; Yamaguchi, Y.; Yoshizawa, M.

2002-10-01

162

A gain monitoring system for scintillation detectors using ultra bright LEDs  

NASA Astrophysics Data System (ADS)

A gain monitoring system based on ultra bright LEDs was developed for the scintillation counters of the PiP/TOF detectors to be employed in (?, NN) experiments at the 855 MeV microtron MAMI-B in Mainz. The intensive light pulses of one LED supplied 16 photomultipliers simultaneously and one PIN diode for monitoring. The stability of the corrected photomultiplier gain is better than 0.5%. The LED pulses were also used to calibrate the time walk of the leading edge discriminators.

Hehl, T.; Grabmayr, P.; Sauer, M.; Wagner, G. J.

1995-02-01

163

Alignment of the Near Detector scintillator modules using cosmic ray muons  

SciTech Connect

The authors describe the procedures and the results of the first alignment of the Near Detector. Using 15.5 million cosmic ray muon tracks, collected from October, 2004 through early january, 2005, they derive the effective transverse positions of the calorimeter scintillator modules. The residuals from straight line fits indicate that the current alignment has achieved better than 1 mm precision. They estimate the size of the remaining misalignment and using tracks recorded with a magnetic field test the effect of the magnetic field on the alignment.

Ospanov, Rustem; Lang, Karol; /Texas U.

2008-05-01

164

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

SciTech Connect

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.

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

165

Predicting the sensitivity of the beryllium/scintillator layer neutron detector using Monte Carlo and experimental response functionsa)  

NASA Astrophysics Data System (ADS)

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.

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

166

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

SciTech Connect

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.

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

167

Monte Carlo and analytical models of neutron detection with organic scintillation detectors  

NASA Astrophysics Data System (ADS)

This paper presents a new technique for the analysis of neutron pulse height distributions generated in an organic scintillation detector. The methodology presented can be applied to techniques such as neutron spectrum unfolding, which have a variety of applications, including nuclear nonproliferation and homeland security. The technique is based on two independent approaches: (i) the use of the MCNP-PoliMi code to simulate neutron detection on an event-by-event basis with the Monte Carlo method and (ii) an analytical approach for neutron slowing down and detection processes. We show that the total neutron pulse height response measured by the organic scintillators is given by the sum of a large number of different neutron histories, each composed of a certain number of neutron scatterings on hydrogen and/or carbon. The relative contributions of each of these histories are described for a cylindrical liquid scintillator BC-501A. Simulations and measurements of neutron pulse height distributions are essential for neutron spectrum unfolding procedures.

Pozzi, Sara A.; Flaska, Marek; Enqvist, Andreas; Pázsit, Imre

2007-11-01

168

Improving Photoelectron Counting and Particle Identification in Scintillation Detectors with Bayesian Techniques  

E-print Network

Many current and future dark matter and neutrino detectors are designed to measure scintillation light with a large array of photomultiplier tubes (PMTs). The energy resolution and particle identification capabilities of these detectors depend in part on the ability to accurately identify individual photoelectrons in PMT waveforms despite large variability in pulse amplitudes and pulse pileup. We describe a Bayesian technique that can identify the times of individual photoelectrons in a sampled PMT waveform without deconvolution, even when pileup is present. To demonstrate the technique, we apply it to the general problem of particle identification in single-phase liquid argon dark matter detectors. Using the output of the Bayesian photoelectron counting algorithm described in this paper, we construct several test statistics for rejection of backgrounds for dark matter searches in argon. Compared to simpler methods based on either observed charge or peak finding, the photoelectron counting technique improves both energy resolution and particle identification of low energy events in calibration data from the DEAP-1 detector and simulation of the larger MiniCLEAN dark matter detector.

M. Akashi-Ronquest; P. -A. Amaudruz; M. Batygov; B. Beltran; M. Bodmer; M. G. Boulay; B. Broerman; B. Buck; A. Butcher; B. Cai; T. Caldwell; M. Chen; Y. Chen; B. Cleveland; K. Coakley; K. Dering; F. A. Duncan; J. A. Formaggio; R. Gagnon; D. Gastler; F. Giuliani; M. Gold; V. V. Golovko; P. Gorel; K. Graham; E. Grace; N. Guerrero; V. Guiseppe; A. L. Hallin; P. Harvey; C. Hearns; R. Henning; A. Hime; J. Hofgartner; S. Jaditz; C. J. Jillings; C. Kachulis; E. Kearns; J. Kelsey; J. R. Klein; M. Kuzniak; A. LaTorre; I. Lawson; O. Li; J. J. Lidgard; P. Liimatainen; S. Linden; K. McFarlane; D. N. McKinsey; S. MacMullin; A. Mastbaum; R. Mathew; A. B. McDonald; D. -M. Mei; J. Monroe; A. Muir; C. Nantais; K. Nicolics; J. A. Nikkel; T. Noble; E. O'Dwyer; K. Olsen; G. D. Orebi Gann; C. Ouellet; K. Palladino; P. Pasuthip; G. Perumpilly; T. Pollmann; P. Rau; F. Retiere; K. Rielage; R. Schnee; S. Seibert; P. Skensved; T. Sonley; E. Vazquez-Jauregui; L. Veloce; J. Walding; B. Wang; J. Wang; M. Ward; C. Zhang

2014-12-12

169

Neutron energy spectrum measurements with a compact liquid scintillation detector on EAST  

NASA Astrophysics Data System (ADS)

A neutron detector based on EJ301 liquid scintillator has been employed at EAST to measure the neutron energy spectrum for D-D fusion plasma. The detector was carefully characterized in different quasi-monoenergetic neutron fields generated by a 4.5 MV Van de Graaff accelerator. In recent experimental campaigns, due to the low neutron yield at EAST, a new shielding device was designed and located as close as possible to the tokamak to enhance the count rate of the spectrometer. The fluence of neutrons and ?-rays was measured with the liquid neutron spectrometer and was consistent with 3He proportional counter and NaI(Tl) ?-ray spectrometer measurements. Plasma ion temperature values were deduced from the neutron spectrum in discharges with lower hybrid wave injection and ion cyclotron resonance heating. Scattered neutron spectra were simulated by the Monte Carlo transport Code, and they were well verified by the pulse height measurements at low energies.

Yuan, X.; Zhang, X.; Xie, X.; Gorini, G.; Chen, Z.; Peng, X.; Chen, J.; Zhang, G.; Fan, T.; Zhong, G.; Hu, L.; Wan, B.

2013-07-01

170

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

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

171

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

PubMed

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. PMID:23020376

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

2012-09-01

172

Bismuth germanate scintillators as detectors for high-energy gamma radiation  

NASA Astrophysics Data System (ADS)

The properties of bismuth germanate (BGO) relevant to the detection of high-energy gamma-rays are discussed on the basis of a comparison between a 76 mm diameter by 76 mm long BGO scintillator and a 152 mm diameter by 254 mm long NaI(Tl) crystal. The two detectors were exposed to monoenergetic gamma rays from the 12C(p, p'?) 12C reaction at the proton energy 17 MeV ( E? = 4.44, 12.71 and 15.11 MeV) and from the 1H(t, ?) 4He reaction at the triton energy 9 MeV( E? = MeV). The bismuth germanate detector has several properties which are important for the detection of high-energy gamma radiation.

Drake, Darrell M.; Nilsson, Leif R.; Faucett, John

173

Unfolding the fast neutron spectra of a BC501A liquid scintillation detector using GRAVEL method  

NASA Astrophysics Data System (ADS)

Accurate knowledge of the neutron energy spectra is useful in basic research and applications. The overall procedure of measuring and unfolding the fast neutron energy spectra with BC501A liquid scintillation detector is described. The recoil proton spectrum of 241Am-Be neutrons was obtained experimentally. With the NRESP7 code, the response matrix of detector was simulated. Combining the recoil proton spectrum and response matrix, the unfolding of neutron spectra was performed by GRAVEL iterative algorithm. A MatLab program based on the GRAVEL method was developed. The continuous neutron spectrum of 241Am-Be source and monoenergetic neutron spectrum of D-T source have been unfolded successfully and are in good agreement with their standard reference spectra. The unfolded 241Am-Be spectrum are more accurate than the spectra unfolded by artificial neural networks in recent years.

Chen, YongHao; Chen, XiMeng; Lei, JiaRong; An, Li; Zhang, XiaoDong; Shao, JianXiong; Zheng, Pu; Wang, XinHua

2014-10-01

174

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

SciTech Connect

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.

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

175

Performance assessment of a 2D array of plastic scintillation detectors for IMRT quality assurance.  

PubMed

The purposes of this work are to assess the performance of a 2D plastic scintillation detectors array prototype for quality assurance in intensity-modulated radiation therapy (IMRT) and to determine its sensitivity and specificity to positioning errors of one multileaf collimator (MLC) leaf and one MLC leaf bank by applying the principles of signal detection theory. Ten treatment plans (step-and-shoot delivery) and one volumetric modulated arc therapy plan were measured and compared to calculations from two treatment-planning systems (TPSs) and to radiochromic films. The averages gamma passing rates per beam found for the step-and-shoot plans were 95.8% for the criteria (3%, 2 mm), 97.8% for the criteria (4%, 2 mm), and 98.1% for the criteria (3%, 3 mm) when measurements were compared to TPS calculations. The receiver operating characteristic curves for the one leaf errors and one leaf bank errors were determined from simulations (theoretical upper limits) and measurements. This work concludes that arrays of plastic scintillation detectors could be used for IMRT quality assurance in clinics. The use of signal detection theory could improve the quality of dosimetric verifications in radiation therapy by providing optimal discrimination criteria for the detection of different classes of errors. PMID:23756497

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

2013-07-01

176

Thin-film-based scintillators for hard x-ray microimaging detectors: the ScinTAX Project  

NASA Astrophysics Data System (ADS)

The project ScinTAX developed novel thin scintillating films for the application in high performance X-ray imaging and subsequent introduced new X-ray detectors to the market. To achieve this aim lutetium orthosilicate (LSO) scintillators doped with different activators were grown successfully by liquid phase epitaxy. The high density of LSO (7.4 g/cm3), the effective atomic number (65.2) and the high light yield make this scintillator highly applicable for indirect X-ray detection in which the ionizing radiation is converted into visible light and then registered by a digital detector. A modular indirect detection system has been developed to fully exploit the potential of this thin film scintillator for radiographic and tomographic imaging. The system is compatible for high-resolution imaging with moderate dose as well as adaptable to intense high-dose applications where radiation hard microimaging detectors are required. This proceedings article shall review the achieved performances and technical details on this high-resolution detector system which is now available. A selected example application demonstrates the great potential of the optimized detector system for hard X-ray microimaging, i.e. either to improve image contrast due to the availability of efficient thin crystal films or to reduce the dose to the sample.

Rack, A.; Cecilia, A.; Douissard, P.-A.; Dupré, K.; Wesemann, V.; Baumbach, T.; Couchaud, M.; Rochet, X.; Riesemeier, H.; Radtke, M.; Martin, T.

2014-09-01

177

Performance of lanthanide-halide scintillation detectors in prompt gamma analysis of bulk samples  

NASA Astrophysics Data System (ADS)

Performance tests of cylindrical 3" x 3" (LaBr3:Ce and LaCl3:Ce) and 5" x 5" (BGO) detectors were carried out to detect low energy prompt gamma-rays from boron contaminated water samples using a newly designed portable neutron generator-based Prompt Gamma Neutron Activation Analysis (PGNAA) setup. Prompt gamma-rays were measured from water samples contaminated with 0.031 to 0.5 wt% boron. The experimental yield of boron prompt gamma-rays measured with LaBr3:Ce, LaCl3:Ce and BGO detectors based PGNAA setup were compared. An excellent agreement has been observed between the experimental and calculated yield of boron prompt gamma ray from water samples. Minimum detection concentrations (MDC)s of boron in water samples for LaBr3:Ce, LaCl3:Ce and BGO detectors were determined to be: 30 ± 9.3, 45 ± 16.4, 28 ± 8 (ppm) respecteviley which agree with each other within statistical uncertainty.

Al-Anezi, Mohammad Saleh

178

Response characterization for an EJ315 deuterated organic-liquid scintillation detector for neutron spectroscopy  

NASA Astrophysics Data System (ADS)

Organic liquid scintillation detectors have shown promise as neutron detectors for characterizing special nuclear materials in various arms-control applications. Deuterated liquids, such as EJ315, are attractive for spectroscopy applications because the backward-peaked n-d scattering results in enhanced coupling between incident neutron energy and resulting pulse height. This will likely allow better spectrum unfolding. In this work, we present a measured neutron response matrix for a three-by-two-in. cylindrical EJ315 detector, and compare to the hydrogen-based liquid EJ309 in an otherwise identical assembly. We also present measured light-output relations for both detectors. A continuous-spectrum neutron source, obtained with the bombardment of 11B with 5.5-MeV deuterons at the tandem Van de Graaff accelerator at the University of Notre Dame, was used for the measurement. Detected neutrons were sorted via time of flight into 100-keV energy groups, over the energy range from 0.5 to 15 MeV. The resulting response matrix represents a detailed characterization of pulse-height response to neutrons over that energy range. To the authors' knowledge, a measured response matrix and light-output relation for EJ315 have not been reported, and published characterizations of the similar NE230 are of less detail over this energy range. Matrix-condition analysis indicates an advantage for EJ315 over EJ309 in the number of independent parameters available in inversion procedures.

Lawrence, Chris C.; Enqvist, Andreas; Flaska, Marek; Pozzi, Sara A.; Howard, A. M.; Kolata, J. J.; Becchetti, F. D.

2013-11-01

179

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

SciTech Connect

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.

Proudfoot, J.

1992-09-01

180

A PET detector prototype based on digital SiPMs and GAGG scintillators.  

PubMed

Silicon Photomultipliers (SiPM) are interesting light sensors for Positron Emission Tomography (PET). The detector signal of analog SiPMs is the total charge of all fired cells. Energy and time information have to be determined with dedicated readout electronics. Philips Digital Photon Counting has developed a SiPM with added electronics on cell level delivering a digital value of the time stamp and number of fired cells. These so called Digital Photon Counters (DPC) are fully digital devices. In this study, the feasibility of using DPCs in combination with LYSO (Lutetium Yttrium Oxyorthosilicate) and GAGG (Gadolinium Aluminum Gallium Garnet) scintillators for PET is tested. Each DPC module has 64 channels with 3.2 × 3.8775 mm(2), comprising 3200 cells each. GAGG is a recently developed scintillator (Zeff = 54, 6.63 g cm(-3), 520 nm peak emission, 46?000 photons MeV(-1), 88 ns (92%) and 230 ns (8%) decay times, non-hygroscopic, chemically and mechanically stable). Individual crystals of 2 × 2 × 6 mm(3) were coupled onto each DPC pixel. LYSO coupled to the DPC results in a coincidence time resolution (CTR) of 171 ps FWHM and an energy resolution of 12.6% FWHM at 511 keV. Using GAGG, coincidence timing is 310 ps FWHM and energy resolution is 8.5% FWHM. A PET detector prototype with 2 DPCs equipped with a GAGG array matching the pixel size (3.2 × 3.8775 × 8 mm(3)) was assembled. To emulate a ring of 10 modules, objects are rotated in the field of view. CTR of the PET is 619 ps and energy resolution is 9.2% FWHM. The iterative MLEM reconstruction is based on system matrices calculated with an analytical detector response function model. A phantom with rods of different diameters filled with (18)F was used for tomographic tests. PMID:25633017

Schneider, Florian R; Shimazoe, Kenji; Somlai-Schweiger, Ian; Ziegler, Sibylle I

2015-02-21

181

Spatial and spectral gamma-ray response of plastic scintillators used in portal radiation detectors; comparison of measurements and simulations  

NASA Astrophysics Data System (ADS)

Portal radiation detectors are commonly used by steel industries in the probing and detection of radioactivity contamination in scrap metal. Furthermore, a large number of portal monitors are installed at the border crossings to prevent illegal radioactive material trafficking. These portal detectors typically consist of either PS (polystyrene) or PVT (polyvinyltoluene) plastic scintillating detectors. Through the electronic circuit of the detector, an energy region-of-interest window can be determined in order to focus on the detection of certain radionuclides. In this study, the spatial response of a portal's PS scintillator to a Cs-137 and a Co-60 source for various energy region-of-interest windows is presented. Furthermore, a number of measured spectra for different source positions on the surface of the scintillating detector are shown. The measured spatial response showed a quantitative and qualitative dependence on the energy window used each time. In addition, measured spectra showed energy shifts for different positions of the two sources on the detector surface. The aforementioned phenomena could not be adequately explained and modelled using gamma-particle transport Monte Carlo simulation tools, such as the MCNP4C2 code. In order to fully explain these phenomena, we performed optical simulations, modelling the transport of the light yield within the detector, using Gate v3.0.0 with Geant 4.8.0p01 of CERN. The results of those simulations are presented and compared to the measured ones.

Takoudis, G.; Xanthos, S.; Clouvas, A.; Antonopoulos-Domis, M.; Potiriadis, C.; Silva, J.

2009-02-01

182

Real-time scintillation array dosimetry for radiotherapy: The advantages of photomultiplier detectors  

SciTech Connect

Purpose: In this paper, a photomultiplier tube (PMT) array dosimetry system has been developed and tested for the real-time readout of multiple scintillation signals from fiber optic dosimeters. It provides array dosimetry with the advantages in sensitivity provided by a PMT, but without the need for a separate PMT for each detector element. Methods: The PMT array system consisted of a multianode PMT, a multichannel data acquisition system, housing and optic fiber connections suitable for clinical use. The reproducibility, channel uniformity, channel crosstalk, acquisition speed, and sensitivity of the PMT array were quantified using a constant light source. Its performance was compared to other readout systems used in scintillation dosimetry. An in vivo HDR brachytherapy treatment was used as an example of a clinical application of the dosimetry system to the measurement of dose at multiple sites in the rectum. The PMT array system was also tested in the pulsed beam of a linear accelerator to test its response speed and its application with two separate methods of Cerenkov background removal. Results: The PMT array dosimetry system was highly reproducible with a measurement uncertainty of 0.13% for a 10 s acquisition period. Optical crosstalk between neighboring channels was accounted for by omitting every second channel. A mathematical procedure was used to account for the crosstalk in next-neighbor channels. The speed and sensitivity of the PMT array system were found be superior to CCD cameras, allowing for measurement of more rapid changes in dose rate. This was further demonstrated by measuring the dose delivered by individual photon pulses of a linear accelerator beam. Conclusions: The PMT array system has advantages over CCD camera-based systems for the readout of scintillation light. It provided a more sensitive, more accurate, and faster response to meet the demands of future developments in treatment delivery.

Liu, Paul Z. Y.; Suchowerska, Natalka; Abolfathi, Peter; McKenzie, David R. [School of Physics, University of Sydney, New South Wales 2006, Australia and Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, New South Wales 2050 (Australia); School of Physics, University of Sydney, New South Wales 2006 (Australia)

2012-04-15

183

Fiber optic thermal/fast neutron and gamma ray scintillation detector  

DOEpatents

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.

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

2007-10-30

184

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

Microsoft Academic Search

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

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

2011-01-01

185

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

SciTech Connect

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.

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

186

Prototype scintillator cell for an In-based solar neutrino detector  

E-print Network

We describe the work carried out at MPIK to design, model, build and characterize a prototype cell filled with a novel indium-loaded scintillator of interest for real-time low energy solar neutrino spectroscopy. First, light propagation in optical modules was studied with experiments and Monte Carlo simulations. Subsequently a 5 cm x 5 cm x 100 cm prototype detector was set up and the optical performances of several samples were measured. We first tested a benchmark PXE-based scintillator, which performed an attenuation length of ~ 4.2 m and a photo-electron yield of ~ 730 pe/MeV. Then we measured three In-loaded samples. At an In-loading of 44 g/l, an energy resolution of ~ 11.6 % and a spatial resolution of ~ 7 cm were attained for 477 keV recoil electrons. The long-range attenuation length in the cell was ~1.3 m and the estimated photo-electron yield ~ 200 pe/MeV. Light attenuation and relative light output of all tested samples could be reproduced reasonably well by MC. All optical properties of this syst...

Motta, D; Hartmann, F X; Lasserre, T; Schönert, S; Schwan, U; Motta, Dario; Buck, Christian; Hartmann, Francis Xavier; Lasserre, Thierry; Sch\\"{o}nert, Stefan; Schwan, Ute

2005-01-01

187

Development of a gadolinium-loaded liquid scintillator for the Hanaro short baseline prototype detector  

NASA Astrophysics Data System (ADS)

We propose a new experiment on the site of the Korea Atomic Energy Research Institute (KAERI) located at Daejeon, Korea. The Hanaro short baseline (SBL) nuclear reactor with a thermal power output 30 MW is used to investigate a reactor neutrino anomaly. A Hanaro SBL prototype detector having a 60- l volume has been constructed ˜6 m away from the reactor core. A gadolinium (Gd)-loaded liquid scintillator (LS) is used as an active material to trigger events. The selection of the LS is guided by physical and technical requirements, as well as safety considerations. A linear alkyl benzene (LAB) is used as a base solvent of the Hanaro SBL prototype detector. Three g/ l of PPO and 30 mg/ l of bis-MSB are dissolved to formulate the LAB-based LS. Then, a 0.5% gadolinium (Gd) complex with carboxylic acid is loaded into the LAB-based LS by using the liquidliquid extraction method. In this paper, we will summarize all the characteristics of the Gd-loaded LAB-based LS for the Hanaro prototype detector.

Yeo, In Sung; Joo, Kyung Kwang; So, Sun Heang; Song, Sook Hyung; Kim, Hong Joo; So, Jung Ho; Park, Kang Soon; Ma, Kyung Ju; Jeon, Eun Ju; Kim, Jin Yu; Kim, Young Duk; Lee, Jason; Lee, Jeong-Yeon; Sun, Gwang-Min

2014-02-01

188

Toward a real-time in vivo dosimetry system using plastic scintillation detectors  

PubMed Central

Purpose In this work, we present and validate a plastic scintillation detector (PSD) system designed for real-time multi-probe in vivo measurements. Methods and Materials The PSDs were built with a dose-sensitive volume of 0.4 mm3. PSDs were assembled into modular detector patches, each containing 5 closely packed PSDs. Continuous dose readings were performed every 150 ms, with a gap between consecutive readings of less than 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 are compatible with clinical rectal balloons and are easily inserted into the anthropomorphic phantom. With an electron multiplication average gain factor of 40, a twofold increase in the signal-to-noise ratio was observed, making near real-time dosimetry feasible. Under calibration conditions, the PSDs agreed with 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 radiation therapy should help radiation oncologists protect this sensitive normal structure. PMID:20231074

Archambault, Louis; Briere, Tina M.; Pönisch, Falk; Beaulieu, Luc; Kuban, Deborah A.; Lee, Andrew; Beddar, Sam

2010-01-01

189

A position sensitive gamma-ray detector based on silicon drift detectors coupled to scintillators for application in the MEGA Compton telescope  

Microsoft Academic Search

An array of gamma-ray detectors based on silicon drift detectors (SDD) coupled to thallium activated cesium iodide (CsI(Tl)) scintillating crystals is presented. Because of SDDs low output capacitance and the possibility to have the first amplifying stage directly integrated on chip, SDDs show better noise performance than traditional p-i-n photodiodes. The array is read out with custom made ASICs built

M. Marisaldi; C. Labanti; A. Bulgarelli; A. Andritschke; G. Di Cocco; G. Kanbach; F. Gianotti; A. Mauri; E. Rossi; A. Traci; M. Trifoglio

2004-01-01

190

Borexino: A real time liquid scintillator detector for low energy solar neutrino study  

E-print Network

Borexino is a large unsegmented calorimeter featuring 300 tons of liquid scintillator, contained in a 8.5 meter nylon vessel, viewed by 2200 PMTs. The main goal of Borexino is the study, in real time, of low energy solar neutrinos, and in particular, the monoenergetic neutrinos coming from $^7Be$, which is one of the missing links on the solar neutrino problem. The achievement of high radiopurity level, in the order of $10^{-16} g/g$ of U/Th equivalent, necessary to the detection of the low energy component of the solar neutrino flux, was proved in the Borexino prototype: the Counting Test Facility. The detector is located underground in the Laboratori Nazionali del Gran Sasso in the center of Italy at 3500 meter water equivalent depth. In this paper the science and technology of Borexino are reviewed and its main capabilities are presented.

Lino Miramonti

2002-06-25

191

Time and position sensitive single photon detector for scintillator read-out  

E-print Network

We have developed a photon counting detector system for combined neutron and gamma radiography which can determine position, time and intensity of a secondary photon flash created by a high-energy particle or photon within a scintillator screen. The system is based on a micro-channel plate photomultiplier concept utilizing image charge coupling to a position- and time-sensitive read-out anode placed outside the vacuum tube in air, aided by a standard photomultiplier and very fast pulse-height analyzing electronics. Due to the low dead time of all system components it can cope with the high throughput demands of a proposed combined fast neutron and dual discrete energy gamma radiography method (FNDDER). We show tests with different types of delay-line read-out anodes and present a novel pulse-height-to-time converter circuit with its potential to discriminate gamma energies for the projected FNDDER devices for an automated cargo container inspection system (ACCIS).

Sven Schössler; Benjamin Bromberger; Michal Brandis; Lothar Ph. H. Schmidt; Kai Tittelmeier; Achim Czasch; Volker Dangendorf; Ottmar Jagutzki

2012-02-10

192

A large area plastic scintillator detector array for fast neutron measurements  

NASA Astrophysics Data System (ADS)

A large area plastic scintillator detector array ( ˜1×1 m2) has been set up for fast neutron spectroscopy at the BARC-TIFR Pelletron laboratory, Mumbai. The energy, time and position response has been measured for electrons using radioactive sources and for monoenergetic neutrons using the 7Li (p,n1)7Be*(0.429 MeV) reaction at proton energies between 6.3 and 19 MeV. A Monte Carlo simulation of the energy dependent efficiency of the array for neutron detection is in agreement with the 7Li (p,n1) measurements. The array has been used to measure the neutron spectrum, in the energy range of 4-12 MeV, in the reaction C12+Nb93 at E(C12)=40 MeV. This is in reasonable agreement with a statistical model calculation.

Rout, P. C.; Chakrabarty, D. R.; Datar, V. M.; Kumar, Suresh; Mirgule, E. T.; Mitra, A.; Nanal, V.; Kujur, R.

2009-01-01

193

Measuring Muon-Induced Neutrons with Liquid Scintillation Detector at Soudan Mine  

E-print Network

We report a direct detection of muon-induced high energy neutrons with a 12-liter neutron detector fabricated with EJ-301 liquid scintillator operating at Soudan Mine for about two years. The detector response to energy from a few MeV up to $\\sim$ 20 MeV has been calibrated using radioactive sources and cosmic-ray muons. Subsequently, we have calculated the scintillation efficiency for nuclear recoils, up to a few hundred MeV, using Birks' law in the Monte Carlo simulation. Data from an exposure of 655.1 days were analyzed and neutron-induced recoil events were observed in the energy region from 4 MeV to 50 MeV, corresponding to fast neutrons with kinetic energy up to a few hundred MeV, depending on the scattering angle. Combining with the Monte Carlo simulation, the muon-induced fast neutron flux is determined to be $(2.3 \\pm 0.52 (sta.) \\pm 0.99 (sys.) ) \\times10^{-9}$ cm$^{-2}$s$^{-1}$ (E$_{n}$ $>$ 20 MeV), in a reasonable agreement with the model prediction. The muon flux is found to be ($1.65\\pm 0.02 (sta.) \\pm 0.1 (sys.) ) \\times10^{-7}$ cm$^{-2}$s$^{-1}$ (E$_{\\mu}$ $>$ 1 GeV), consistent with other measurements. As a result, the muon-induced high energy gamma-ray flux is simulated to be 7.08 $\\times$10$^{-7}$cm$^{-2}$s$^{-1}$ (E$_{\\gamma}$ $>$ 1 MeV) for the depth of Soudan.

C. Zhang; D. -M. Mei

2014-11-26

194

Energy resolution of small scintillation detectors with SiPM light readout  

NASA Astrophysics Data System (ADS)

The development of silicon photomultipliers (SiPMs) with a large number of APD cells and improved linearity of the pulse height response prompted interest in their application to gamma spectrometry with scintillators. Hamamatsu MPPC sensors equipped with 3600 and 14400 APD cells were chosen in our study because of their well pronounced single photoelectron spectra, which allowed us to precisely measure the photoelectron numbers (PHE) or fired APD cells and then to discuss, in a quantitative manner, the obtainable energy resolution. The studied detectors were first characterized in direct detection of laser light pulses and then in gamma spectroscopy with LFS and CsI:Tl crystals. In the study with the laser light pulses the linearity of the MPPC response versus a light pulse intensity monitored with PMT was measured. Two different methods were used for an evaluation of the MPPC response expressed in the number of photoelectrons (PHE) generated by light illumination. The direct method (PHEdir), based on the comparison of the light peak position to that of the single photoelectron peak, determined the upper limit of the PHE. The lower limit of the PHE was derived from an analysis of the measured pulse height resolution under the assumption of Poisson statistics and MPPC excess noise factor (ENF) of 1. Furthermore, the ENF of the MPPC is discussed with respect to the contributions of device dead time, optical cross-talk and after-pulses to the results obtained. In the scintillation tests, measurements of energy resolution and non-proportionality of the light yield were performed with LFS and CsI:Tl crystals, and both types of 3 × 3 mm MPPC detectors were used for light readout. The results are discussed in a quantitative manner based on the measured PHE.

Grodzicka, M.; Moszy?ski, M.; Szcz??niak, T.; Kapusta, M.; Szaw?owski, M.; Wolski, D.

2013-02-01

195

Measuring muon-induced neutrons with liquid scintillation detector at Soudan mine  

NASA Astrophysics Data System (ADS)

We report a direct detection of muon-induced high-energy neutrons with a 12-liter neutron detector fabricated with EJ-301 liquid scintillator operating at Soudan mine for about two years. The detector response to energy from a few MeV up to ˜20 MeV has been calibrated using radioactive sources and cosmic-ray muons. Subsequently, we have calculated the scintillation efficiency for nuclear recoils, up to a few hundred MeV, using Birks' law in the Monte Carlo simulation. Data from an exposure of 655.1 days were analyzed and neutron-induced recoil events were observed in the energy region from 4 to 50 MeV, corresponding to fast neutrons with kinetic energy up to a few hundred MeV, depending on the scattering angle. Combining with the Monte Carlo simulation, the measured muon-induced fast neutron flux is determined to be (2.23 ±0.52 (sta)±0.99 (sys))×10-9 cm-2 s-1 (En >20 MeV ), in a reasonable agreement with the model prediction. The muon flux is found to be (1.65 ±0.02 (sta)±0.1 (sys))×10-7 cm-2 s-1 (E? >1 GeV ), consistent with other measurements. As a result, the muon-induced high-energy gamma-ray flux is simulated to be 7.08 ×10-7 cm-2 s-1 (E? > 1 MeV ) for the depth of Soudan.

Zhang, C.; Mei, D.-M.

2014-12-01

196

KLauS: an ASIC for silicon photomultiplier readout and its application in a setup for production testing of scintillating tiles  

NASA Astrophysics Data System (ADS)

KLauS is an ASIC produced in the AMS 0.35 ?m SiGe process to read out the charge signals from silicon photomultipliers. Developed as an analog front-end for future calorimeters with high granularity as pursued by the AHCAL concept in the CALICE collaboration, the ASIC is designed to measure the charge signal of the sensors in a large dynamic range and with low electronic noise contributions. In order to tune the operation voltage of each sensor individually, an 8-bit DAC to tune the voltage at the input terminal within a range of 2V is implemented. Using an integrated fast comparator with low jitter, the time information can be measured with sub-nanosecond resolution. The low power consumption of the ASIC can be further decreased using power gating techniques. Future versions of KLauS are under development and will incorporate an ADC with a resolution of up to 12-bits and blocks for digital data transmission. The chip is used in a setup for mass testing and characterization of scintillator tiles for the AHCAL test beam program.

Briggl, K.; Dorn, M.; Hagdorn, R.; Harion, T.; Schultz-Coulon, H. C.; Shen, W.

2014-02-01

197

Characterization of scintillator materials for fast-ion loss detectors in nuclear fusion reactors  

NASA Astrophysics Data System (ADS)

In fusion plasma reactors, fast ion generated by heating systems and fusion born particles must be well confined. The presence of magnetohydrodynamic (MHD) instabilities can lead to a significant loss of these ions, which may reduce drastically the heating efficiency and may cause damage to plasma facing components in the vacuum vessel. In order to understand the physics underlying the fast ion loss mechanism, scintillator based detectors have been installed in several fusion devices. In this work we present the absolute photon yield and its degradation with ion fluence in terms of the number of photons emitted per incident ion of several scintillators thin coatings: SrGa2S4:Eu2+ (TG-Green), Y3Al5O12:Ce3+ (P46) and Y2O3:Eu3+ (P56) when irradiated with light ions of different masses (deuterium ions, protons and ?-particles) at energies between approximately 575 keV and 3 MeV. The photon yield will be discussed in terms of the energy deposited by the particles into the scintillator. For that, the actual composition and thickness of the thin layers were determined by Rutherford Backscattering Spectrometry (RBS). A collimator with 1 mm of diameter, which defines the beam size for the experiments, placed at the entrance of the chamber. An electrically isolated sample holder biased to +300 V to collect the secondary electrons, connected to a digital current integrator (model 439 by Ortec) to measure the incident beam current. A home made device has been used to store the real-time evolution of the beam current in a computer file allowing the correction of the IL yields due to the current fluctuations. The target holder is a rectangle of 150 × 112 mm2 and can be tilted. The X and Y movements are controlled through stepping motors, which permits a fine control of the beam spot positioning as well as the study of several samples without venting the chamber. A silica optical fiber of 1 mm diameter fixed to the vacuum chamber, which collects the light from the scintillators. The solid angle subtended by the fiber is ?2.2 × 10-5 sr. The final element is a compact and high sensitive spectrometer, QE6500 (Ocean Optics Inc.) with a 2D area detector which allow us to measure simultaneously in the range of 200-1100 nm with a spectral resolution ?1-2 nm. The measured signals were analyzed and stored with the SpectraSuite software [6]. The absolute calibration of the optical system described above was carried out with a HL-2000-CAL Tungsten Halogen Calibration Standard light source which provides absolute intensity values (in ?W/cm2/nm) at the fiber port at wavelengths from 360-1050 nm.The beam fluxes used to irradiate the phosphors were ? 1012 p/cm2s- for the IL yields determination, and up to ten times higher for the degradation analyses.The Rutherford Backscattering Spectrometry (RBS) measurements of the screens were accomplished in the same vacuum chamber using protons at 3 MeV and 5 MeV. Two different energies were employed due to the large difference between the thicknesses of the samples. The proton beam intensity was 10 nA and the beam size 1 mm of diameter. The analysis were performed with a Passivated Implanted Planar Silicon (PIPS) detector of 300 mm2, positioned at 150° and with a 10 ?m thick aluminized mylar foil placed at the detector surface to avoid the light emitted by the scintillators. The RBS spectra were analyzed using the SIMNRA code [7].The scintillators investigated in this work were selected according to their availability, radiation hardness, fast response, and/or prior use in plasma diagnostics. In this paper, three different kinds of materials have been analyzed. The TG-Green (so called by the manufacturer, Sarnoff Corporation, USA) is a Eu doped SrGa2S4 powder substrate with density of 3.65 g/cm3, and presents an emission at 540 nm with a very short decay time.?490 ns [8]. A TG-Green scintillator coating has been applied, for the first time, to a fusion plasma diagnostics for the detection of fast-particle losses on the AUG tokamak [9,10]. The same material supplied by other manufacturer (CIEMAT)

Jiménez-Ramos, M. C.; García López, J.; García-Muñoz, M.; Rodríguez-Ramos, M.; Carmona Gázquez, M.; Zurro, B.

2014-08-01

198

Development of neutron-monitor detector using liquid organic scintillator coupled with 6Li + ZnS(Ag) Sheet.  

PubMed

A phoswitch-type detector has been developed for monitoring neutron doses in high-energy accelerator facilities. The detector is composed of a liquid organic scintillator (BC501A) coupled with ZnS(Ag) sheets doped with 6Li. The dose from neutrons with energies above 1 MeV is evaluated from the light output spectrum of the BC501A by applying the G-function, which relates the spectrum to the neutron dose directly. The dose from lower energy neutrons, on the other hand, is estimated from the number of scintillations emitted from the ZnS(Ag) sheets. Characteristics of the phoswitch-type detector were studied experimentally in some neutron fields. It was found from the experiments that the detector has an excellent property of pulse-shape discrimination between the scintillations of BC501A and the ZnS(Ag) sheets. The experimental results also indicate that the detector is capable of reproducing doses from thermal neutrons as well as neutrons with energies from one to several tens of megaelectronvolts (MeV). PMID:15353655

Sato, Tatsuhiko; Endo, Akira; Yamaguchi, Yasuhiro; Takahashi, Fumiaki

2004-01-01

199

A Comparison of Performance Between Organic Scintillation Crystals and Moderated (3)He-Based Detectors for Fission Neutron Detection  

SciTech Connect

Direct detection of fast neutrons using organic scintillators is one alternative to moderated thermal neutron detectors deployed to detect fission neutrons - a relevant question in light of dwindling {sup 3}He supplies. Recent developments in materials science have demonstrated the capability to grow larger crystals in reasonable times. In light of these developments, this study compares the relative performance of a {sup 3}He-based neutron module from a commercially available portal monitor with a theoretical organic scintillator of similar overall size. Stilbene serves as a benchmark with its performance estimated from a combination of energy deposition modeled by radiation transport calculations and an assumption of the lowest neutron energy at which pulse shape discrimination can effectively separate neutron and gamma-ray events. Before intrinsic detection efficiencies on par with moderated detector systems can be achieved, the results point to the need for further advances including significant increases in detector size, especially thickness, and/or lower pulse shape discrimination thresholds.

Robinson, Sharon M [ORNL; Newby, Robert Jason [ORNL; Runkle, Robert Charles [ORNL

2011-01-01

200

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

PubMed Central

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

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

2013-01-01

201

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

E-print Network

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.

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

2014-01-21

202

Setup of cryogenic front-end electronic systems for germanium detectors read-out  

Microsoft Academic Search

Front-end electronic devices for the read-out of ionizing radiation detectors must operate in many cases at cryogenic temperatures. In this work we focus in particular on front-end read-out systems for high-purity germanium (HPGe) detectors, which are usually operated at liquid nitrogen (LN) temperature. We analyze the strong effects that the changed characteristics of the electronic active and passive devices have

F. Zocca; A. Pullia; S. Riboldi; A. D'Andragora; C. Cattadori

2009-01-01

203

Comparison of photon counting and conventional scintillation detectors in a pinhole SPECT system for small animal imaging: Monte carlo simulation studies  

NASA Astrophysics Data System (ADS)

The photon counting detector based on cadmium telluride (CdTe) or cadmium zinc telluride (CZT) is a promising imaging modality that provides many benefits compared to conventional scintillation detectors. By using a pinhole collimator with the photon counting detector, we were able to improve both the spatial resolution and the sensitivity. The purpose of this study was to evaluate the photon counting and conventional scintillation detectors in a pinhole single-photon emission computed tomography (SPECT) system. We designed five pinhole SPECT systems of two types: one type with a CdTe photon counting detector and the other with a conventional NaI(Tl) scintillation detector. We conducted simulation studies and evaluated imaging performance. The results demonstrated that the spatial resolution of the CdTe photon counting detector was 0.38 mm, with a sensitivity 1.40 times greater than that of a conventional NaI(Tl) scintillation detector for the same detector thickness. Also, the average scatter fractions of the CdTe photon counting and the conventional NaI(Tl) scintillation detectors were 1.93% and 2.44%, respectively. In conclusion, we successfully evaluated various pinhole SPECT systems for small animal imaging.

Lee, Young-Jin; Park, Su-Jin; Lee, Seung-Wan; Kim, Dae-Hong; Kim, Ye-Seul; Kim, Hee-Joung

2013-05-01

204

Simulation of the precision limits of plastic scintillation detectors using optimal component selection  

PubMed Central

Purpose: The purpose of this work was threefold: First, to determine which type of charge-coupled device (CCD) would provide the best dosimetric precision for plastic scintillation detectors (PSDs); second, to design a high-photon-efficiency PSD system by optimizing its signal-to-noise ratio (SNR) using off-the-shelf technology; and third, to establish the spatial, temporal, and dose precision limits of such a PSD system. The authors have attempted to design a dosimetric tool suitable for radiotherapy treatment modalities employing small fields or fast temporal modulation of the radiation fields, and to explore the current precision limits of PSD systems. Methods: The authors used an SNR simulation model to design and calculate the dosimetric precision of a PSD employing a fiber taper to couple the optical fiber to the photodetector. The authors also used the SNR simulation model to evaluate the impact of the photodetector performance characteristics on the SNR and to establish the spatial, temporal, and dose precision limits. Results: The authors found that a high-photon-efficiency PSD can provide a precision of 1% in 45 ?s of integration time for a dose rate of 400 cGy?min when a single image is taken, detect a dose of 1 cGy with a detector volume of 0.0007 mm3, and image over 15?000 detectors with a precision of 1% on a 30.7×30.7 mm2 CCD imaging area. Conclusions: These characteristics establish that PSDs theoretically constitute a suitable dosimetric tool for radiotherapy treatment modalities employing small fields or fast temporal modulation of the radiation fields. PMID:20229849

Lacroix, Frédéric; Beaulieu, Luc; Archambault, Louis; Beddar, A. Sam

2010-01-01

205

Monte Carlo investigations of megavoltage cone-beam CT using thick, segmented scintillating detectors for soft tissue visualization.  

PubMed

Megavoltage cone-beam computed tomography (MV CBCT) is a highly promising technique for providing volumetric patient position information in the radiation treatment room. Such information has the potential to greatly assist in registering the patient to the planned treatment position, helping to ensure accurate delivery of the high energy therapy beam to the tumor volume while sparing the surrounding normal tissues. Presently, CBCT systems using conventional MV active matrix flat-panel imagers (AMFPIs), which are commonly used in portal imaging, require a relatively large amount of dose to create images that are clinically useful. This is due to the fact that the phosphor screen detector employed in conventional MV AMFPIs utilizes only approximately 2% of the incident radiation (for a 6 MV x-ray spectrum). Fortunately, thick segmented scintillating detectors can overcome this limitation, and the first prototype imager has demonstrated highly promising performance for projection imaging at low doses. It is therefore of definite interest to examine the potential performance of such thick, segmented scintillating detectors for MV CBCT. In this study, Monte Carlo simulations of radiation energy deposition were used to examine reconstructed images of cylindrical CT contrast phantoms, embedded with tissue-equivalent objects. The phantoms were scanned at 6 MV using segmented detectors having various design parameters (i.e., detector thickness as well as scintillator and septal wall materials). Due to constraints imposed by the nature of this study, the size of the phantoms was limited to approximately 6 cm. For such phantoms, the simulation results suggest that a 40 mm thick, segmented CsI detector with low density septal walls can delineate electron density differences of approximately 2.3% and 1.3% at doses of 1.54 and 3.08 cGy, respectively. In addition, it was found that segmented detectors with greater thickness, higher density scintillator material, or lower density septal walls exhibit higher contrast-to-noise performance. Finally, the performance of various segmented detectors obtained at a relatively low dose (1.54 cGy) was compared with that of a phosphor screen similar to that employed in conventional MV AMFPIs. This comparison indicates that for a phosphor screen to achieve the same contrast-to-noise performance as the segmented detectors approximately 18 to 59 times more dose is required, depending on the configuration of the segmented detectors. PMID:18293571

Wang, Yi; Antonuk, Larry E; El-Mohri, Youcef; Zhao, Qihua; Sawant, Amit; Du, Hong

2008-01-01

206

Determination of the energy dependence of the BC-408 plastic scintillation detector in medium energy x-ray beams  

NASA Astrophysics Data System (ADS)

The energy dependence of the response of BC-408 plastic scintillator (PS), an approximately water-equivalent material, has been investigated by employing standardized x-ray beams. IEC RQA and ISO N series x-ray beam qualities, in the range of 40–100?kVp, were calibrated using a PTW-type ionization chamber. The energy response of a thick BC-408 PS detector was measured using the multichannel pulse height analysis method. The response of BC-408 PS increased gradually with increasing energy in the energy range of 40–80?kVp and then showed a flat behavior at about 80 to 120?kVp. This might be due to the self-attenuation of scintillation light by the scintillator itself and may also be partly due to the ionization quenching, leading to a reduction in the intensity of the light output from the scintillator. The results indicated that the sensitivity drop in BC-408 PS material at lower photon energies may be overcome by adding some high-Z elements to its polyvinyltoluene (PVT) base. The material modification may compensate for the drop in the response at lower photon energies. Thus plastic scintillation dosimetry is potentially suitable for applications in diagnostic radiology.

Yücel, H.; Çubukçu, ?.; Uyar, E.; Engin, Y.

2014-11-01

207

A universal setup for active control of a single-photon detector.  

PubMed

The influence of bright light on a single-photon detector has been described in a number of recent publications. The impact on quantum key distribution (QKD) is important, and several hacking experiments have been tailored to fully control single-photon detectors. Special attention has been given to avoid introducing further errors into a QKD system. We describe the design and technical details of an apparatus which allows to attack a quantum-cryptographic connection. This device is capable of controlling free-space and fiber-based systems and of minimizing unwanted clicks in the system. With different control diagrams, we are able to achieve a different level of control. The control was initially targeted to the systems using BB84 protocol, with polarization encoding and basis switching using beamsplitters, but could be extended to other types of systems. We further outline how to characterize the quality of active control of single-photon detectors. PMID:24517746

Liu, Qin; Lamas-Linares, Antía; Kurtsiefer, Christian; Skaar, Johannes; Makarov, Vadim; Gerhardt, Ilja

2014-01-01

208

A universal setup for active control of a single-photon detector  

NASA Astrophysics Data System (ADS)

The influence of bright light on a single-photon detector has been described in a number of recent publications. The impact on quantum key distribution (QKD) is important, and several hacking experiments have been tailored to fully control single-photon detectors. Special attention has been given to avoid introducing further errors into a QKD system. We describe the design and technical details of an apparatus which allows to attack a quantum-cryptographic connection. This device is capable of controlling free-space and fiber-based systems and of minimizing unwanted clicks in the system. With different control diagrams, we are able to achieve a different level of control. The control was initially targeted to the systems using BB84 protocol, with polarization encoding and basis switching using beamsplitters, but could be extended to other types of systems. We further outline how to characterize the quality of active control of single-photon detectors.

Liu, Qin; Lamas-Linares, Antía; Kurtsiefer, Christian; Skaar, Johannes; Makarov, Vadim; Gerhardt, Ilja

2014-01-01

209

A universal setup for active control of a single-photon detector  

SciTech Connect

The influence of bright light on a single-photon detector has been described in a number of recent publications. The impact on quantum key distribution (QKD) is important, and several hacking experiments have been tailored to fully control single-photon detectors. Special attention has been given to avoid introducing further errors into a QKD system. We describe the design and technical details of an apparatus which allows to attack a quantum-cryptographic connection. This device is capable of controlling free-space and fiber-based systems and of minimizing unwanted clicks in the system. With different control diagrams, we are able to achieve a different level of control. The control was initially targeted to the systems using BB84 protocol, with polarization encoding and basis switching using beamsplitters, but could be extended to other types of systems. We further outline how to characterize the quality of active control of single-photon detectors.

Liu, Qin; Skaar, Johannes [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)] [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Lamas-Linares, Antía; Kurtsiefer, Christian [Centre for Quantum Technologies and Department of Physics, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore)] [Centre for Quantum Technologies and Department of Physics, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Makarov, Vadim, E-mail: makarov@vad1.com [Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada)] [Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Gerhardt, Ilja, E-mail: ilja@quantumlah.org [Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart (Germany)] [Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart (Germany)

2014-01-15

210

A performance study on a phoswich detector consisting of an inner NE213 scintillator and an outer CaF 2(Eu) crystal wall  

NASA Astrophysics Data System (ADS)

We developed a new phoswich detector. The detector consists of an inner NE213 organic liquid scintillator and an outer thin CaF 2(Eu) crystal which are coupled to a photomultiplier. The charged particles produced in the NE213 scintillator by the interaction of radiation with the detector either stop in the NE213 scintillator or pass through both the NE213 scintillator and the outer CaF 2(Eu) crystal. The fast output pulses of a few ns from the NE213 scintillator can easily be separated from the slow output pulses of about 1 ?s from the outer CaF 2(Eu) scintillator. From this difference, the events that the charged particle stops inside NE213 scintillator can be separated out from the events that the charged particle escapes from the inside NE213 detector. The phoswich detector response functions for gamma rays and neutrons measured with the radioactive gamma-ray sources and the neutrons produced by a Be + Cu target bombarded by protons from the cyclotron, and compared with Monte Carlo calculations. It was found that the main characteristics of the NE213 scintillator were not degraded by assembling as a phoswich detector using the CaF 2(Eu) crystal wall. The n-? discrimination property is slightly degraded but neutrons can be separated from gamma rays. Further we used to test the phoswich detector for neutron measurements under the intense charged particles, mainly protons, with considering the possibility of neutron detection in space crafts. It was shown that the phoswich detector is capable of detecting neutrons in the mixed field.

Takada, Masashi; Shibata, Tokushi; Uwamino, Yoshitomo; Nakamura, Takashi

1996-02-01

211

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

NASA Astrophysics Data System (ADS)

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.

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

1994-09-01

212

High efficiency plastic scintillator detector with wavelength-shifting fiber readout for the GLAST Large Area Telescope  

NASA Astrophysics Data System (ADS)

This paper describes the design and performance studies of the scintillator tile detectors for the anti-coincidence detector (ACD) of the Large Area Telescope (LAT) on the Gamma ray Large Area Space Telescope (GLAST), scheduled for launch in early 2008. The scintillator tile detectors utilize wavelength-shifting fibers and have dual-photomultiplier-tube readout. The design requires highly efficient and uniform detection of singly charged relativistic particles over the tile area and must meet all requirements for a launch, as well as operation in a space environment. We present here the design of three basic types of tiles used in the ACD, ranging in size from ˜450 to ˜2500 cm2, all ˜1 cm thick, with different shapes, and with photoelectron yield of ˜20 photoelectrons per minimum ionizing particle at normal tile incidence, uniform over the tile area. Some tiles require flexible clear fiber cables up to 1.5 m long to deliver scintillator light to remotely located photomultiplier tubes.

Moiseev, A. A.; Deering, P. L.; Hartman, R. C.; Johnson, T. E.; Nebel, T. R.; Ormes, J. F.; Thompson, D. J.

2007-12-01

213

A SiPM-based ZnS:$^6$LiF scintillation neutron detector  

E-print Network

In the work presented here we built and evaluated a single-channel neutron detection unit consisting of a ZnS:$^6$LiF scintillator with embedded WLS fibers readout by a SiPM. The unit has a sensitive volume of 2.4 x 2.8 x 50 mm$^3$; 12 WLS fibers of diameter 0.25 mm are uniformly distributed over this volume and are coupled to a 1 x 1 mm$^2$ active area SiPM. We report the following performance parameters: neutron detection efficiency $\\sim 65\\,$% at $1.2\\,\\AA$, background count rate $< 10^{-3}$ Hz, gamma-sensitivity with $^{60}$Co source $< 10^{-6}$, dead time $\\sim 20\\,\\mu$s, multi-count ratio $< 1\\,$%. All these parameters were achieved up to the SiPM dark count rate of $\\sim 2\\,$MHz. We consider such detection unit as an elementary building block for realization of one-dimensional multichannel detectors for applications in the neutron scattering experimental technique. The dimensions of the unit and the number of embedded fibers can be varied to meet the specific application requirements. The upp...

Stoykov, A; Greuter, U; Hildebrandt, M; Schlumpf, N

2014-01-01

214

Clinical Trials of a Urethral Dose Measurement System in Brachytherapy Using Scintillation Detectors  

SciTech Connect

Purpose: To report on the clinical feasibility of a novel scintillation detector system with fiberoptic readout that measures the urethral dose during high-dose-rate brachytherapy treatment of the prostate. Methods and Materials: The clinical trial enrolled 24 patients receiving high-dose-rate brachytherapy treatment to the prostate. After the first 14 patients, three improvements were made to the dosimeter system design to improve clinical reliability: a dosimeter self-checking facility; a radiopaque marker to determine the position of the dosimeter, and a more robust optical extension fiber. Results: Improvements to the system design allowed for accurate dose measurements to be made in vivo. A maximum measured dose departure of 9% from the calculated dose was observed after dosimeter design improvements. Conclusions: Departures of the measured from the calculated dose, after improvements to the dosimetry system, arise primarily from small changes in patient anatomy. Therefore, we recommend that patient response be correlated with the measured in vivo dose rather than with the calculated dose.

Suchowerska, Natalka, E-mail: natalka@email.cs.nsw.gov.a [Radiation Oncology, Royal Prince Alfred Hospital, New South Wales (Australia); School of Physics, University of Sydney, New South Wales (Australia); Jackson, Michael [Radiation Oncology, Prince of Wales Hospital, New South Wales (Australia); Department of Medicine, University of Sydney, New South Wales (Australia); Lambert, Jamil; Yin, Yong Bai [School of Physics, University of Sydney, New South Wales (Australia); Hruby, George [Radiation Oncology, Royal Prince Alfred Hospital, New South Wales (Australia); Department of Medicine, University of Sydney, New South Wales (Australia); McKenzie, David R. [School of Physics, University of Sydney, New South Wales (Australia)

2011-02-01

215

Performance and design study of a directional scintillating fiber detector for 14-MeV neutrons using GEANT  

NASA Astrophysics Data System (ADS)

A directional scintillating fiber detector for 14-MeV neutrons was simulated using the GEANT4 Monte Carlo simulation tool. Detail design aspects of a prototype 14 MeV neutron fiber detector under development were used in the simulation to assess performance and design features of the detector. Saint-Gobain produced, BCF-12, plastic fiber material was used in the prototype development. The fiber consists of a core scintillating material of polystyrene with 0.48 mm × 0.48 mm dimension and an acrylic outer cladding of 0.02 mm thickness. A total of 64 square fibers, each with a cross-sectional area of 0.25 mm2 and length of 100 mm were positioned parallel to each other with a spacing of 2.3 mm (fiber pitch) in the tracking of 14-MeV neutron induced recoil proton (n-p) events. Neutron induced recoil proton events, resulting energy deposition in two collinear fibers, were used in reconstructing a two dimensional (2D) direction of incident neutrons. Blurring of recoil protons signal in measurements was also considered to account uncertainty in direction reconstruction. Reconstructed direction has a limiting angular resolution of 3° due to fiber dimension. Blurring the recoil proton energy resulted in further broadening of the reconstructed direction and the angular resolution was 20°. These values were determined when incident neutron beam makes an angle of 45 degree relative to the front surface of the detector. Comparable values were obtained at other angles of incidence. Results from the present simulation have demonstrated promising directional sensitivity of the scintillating fiber detector under development.

Mengesha, W.; Mascarenhas, N.; Peel, J.; Sunnarborg, D.

2005-09-01

216

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

PubMed

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

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

2013-05-21

217

R & D results on scintillating tile\\/fiber calorimetry for the CDF and SDC detectors  

Microsoft Academic Search

We present results from R&D on scintillating tile calorimeters with wavelength-shifter-doped optical fiber readout. Studies of absolute light yields and measurements of spatial uniformity of response of various tile\\/fiber assemblies are described. Preliminary results on radiation hardness of the scintillating tile\\/fiber components are also presented.

P. de Barbaro; A. Bodek; R. S. Budd; Q. Fan; W. K. Sakumoto; B. Winer; J. Proudfoot; D. G. Underwood; G. W. Foster; J. Freeman; D. H. Kim; P. J. Limon; Y. Fukui; M. Mishina; V. Barnes; G. Apollinari; N. Giokaris; K. Goulianos; S. White

1992-01-01

218

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

PubMed Central

Purpose: Photon dosimetry in the kilovolt (kV) energy range represents a major challenge for diagnostic and interventional radiology and superficial therapy. Plastic scintillation detectors (PSDs) are potentially good candidates for this task. This study proposes a simple way to obtain accurate correction factors to compensate for the response of PSDs to photon energies between 80 and 150 kVp. The performance of PSDs is also investigated to determine their potential usefulness in the diagnostic energy range. Methods: A 1-mm-diameter, 10-mm-long PSD was irradiated by a Therapax SXT 150 unit using five different beam qualities made of tube potentials ranging from 80 to 150 kVp and filtration thickness ranging from 0.8 to 0.2 mmAl + 1.0 mmCu. The light emitted by the detector was collected using an 8-m-long optical fiber and a polychromatic photodiode, which converted the scintillation photons to an electrical current. The PSD response was compared with the reference free air dose rate measured with a calibrated Farmer NE2571 ionization chamber. PSD measurements were corrected using spectra-weighted corrections, accounting for mass energy-absorption coefficient differences between the sensitive volumes of the ionization chamber and the PSD, as suggested by large cavity theory (LCT). Beam spectra were obtained from x-ray simulation software and validated experimentally using a CdTe spectrometer. Correction factors were also obtained using Monte Carlo (MC) simulations. Percent depth dose (PDD) measurements were compensated for beam hardening using the LCT correction method. These PDD measurements were compared with uncorrected PSD data, PDD measurements obtained using Gafchromic films, Monte Carlo simulations, and previous data. Results: For each beam quality used, the authors observed an increase of the energy response with effective energy when no correction was applied to the PSD response. Using the LCT correction, the PSD response was almost energy independent, with a residual 2.1% coefficient of variation (COV) over the 80–150-kVp energy range. Monte Carlo corrections reduced the COV to 1.4% over this energy range. All PDD measurements were in good agreement with one another except for the uncorrected PSD data, in which an over-response was observed with depth (13% at 10 cm with a 100 kVp beam), showing that beam hardening had a non-negligible effect on the PSD response. A correction based on LCT compensated very well for this effect, reducing the over-response to 3%. Conclusion: In the diagnostic energy range, PSDs show high-energy dependence, which can be corrected using spectra-weighted mass energy-absorption coefficients, showing no considerable sign of quenching between these energies. Correction factors obtained by Monte Carlo simulations confirm that the approximations made by LCT corrections are valid. Thus, PSDs could be useful for real-time dosimetry in radiology applications. PMID:22957599

Lessard, François; Archambault, Louis; Plamondon, Mathieu; Després, Philippe; Therriault-Proulx, François; Beddar, Sam; Beaulieu, Luc

2012-01-01

219

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)

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.

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

2011-03-01

220

Study of scintillation, fluorescence and scattering in mineral oil for the MiniBooNE neutrino detector  

SciTech Connect

The MiniBooNE neutrino detector at Fermilab (FNAL) is filled with 250,000 gallons of pure mineral oil. The principal signal for MiniBooNE is light observed in a prompt Cherenkov cone. Scattering and fluorescence modify our detection of this light. Scintillation is also created by ionization in the oil. Studies of fluorescence of this oil have been carried out over a wide spectrum of exciting light and time resolved fluorescence with a narrower range of excitation. Polarized scattering measurements have been carried out at longer wavelengths. Time resolved and spectrally resolved scintillation has been studied with a 200 MeV Proton beam at the Indiana University Cyclotron Facility. Results of these studies will be reported.

Brown, Bruce C.; Brice, Stephen; Hawker, Eric; Maza, Shannon; Meyer, Hans-Otto; Pla-Dalmau, Anna; Tayloe, Rex; Tanaka, Hirohisa A.; Toptygin, Dmitri; /Fermilab /Western

2004-11-01

221

Directional neutron detectors for use with 14 MeV neutrons :fiber scintillation methods for directional neutron detection.  

SciTech Connect

Current Joint Test Assembly (JTA) neutron monitors rely on knock-on proton type detectors that are susceptible to X-rays and low energy gamma rays. We investigated two novel plastic scintillating fiber directional neutron detector prototypes. One prototype used a fiber selected such that the fiber width was less than 2.1mm which is the range of a proton in plastic. The difference in the distribution of recoil proton energy deposited in the fiber was used to determine the incident neutron direction. The second prototype measured both the recoil proton energy and direction. The neutron direction was determined from the kinematics of single neutron-proton scatters. This report describes the development and performance of these detectors.

Sunnarborg, Duane A.; Peel, Justin D.; Mascarenhas, Nicholas; Mengesha, Wondwosen

2005-10-01

222

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

Microsoft Academic Search

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.

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

2011-01-01

223

Bismuth germanate scintillator as a fast high-energy ion detector  

NASA Astrophysics Data System (ADS)

The pulse-height response and timing characteristics of bismuth germanate scintillator haven been determined for light and heavy ions (A ? 35 E ? 250 MeV). Timing resolutions of ? 250 ps have been observed.

Becchetti, F. D.; Lister, P. M.; Thorn, C. E.

1984-08-01

224

Study of digital pulse shape discrimination method for n-{\\gamma} separation of EJ-301 liquid scintillation detector  

E-print Network

A digital pulse shape discrimination system based on a programmable module NI-5772 has been established and tested with EJ-301 liquid scintillation detector. The module was operated by means of running programs developed in LabVIEW with the sampling frequency up to 1.6GS/s. Standard gamma sources 22Na, 137Cs and 60Co were used to calibrate the EJ-301 liquid scintillation detector, and the gamma response function has been obtained. Digital algorithms for charge comparison method and zero-crossing method have been developed. The experimental results showed that both digital signal processing (DSP) algorithms could discriminate neutrons from gamma-rays. Moreover, the zero-crossing method shows better n-{\\gamma} discrimination at 80 keVee and lower, whereas the charge comparison method gives better results at higher thresholds. In addition, the figure-of-merit (FOM) of two different dimension detectors were extracted at 9 energy thresholds, and it was found that the smaller one presented a better n-{\\gamma} separ...

Wan, Bo; Chen, Liang; Ge, Honglin; Ma, Fei; Zhang, Hongbin; Ju, Yongqin; Zhang, Yanbin; Li, Yanyan; Xu, Xiaowei

2015-01-01

225

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

SciTech Connect

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.

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

226

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

NASA Astrophysics Data System (ADS)

Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection (10B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where 3He proportional counters are embedded in a polyethylene matrix. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on a pulse-by-pulse basis using custom integrator and timing circuits. In addition, a custom time-tag module was used to provide a time for each detector event. Analysis of the combined energy and time event stream was performed by calibrating each detector's response and filtering based on the presence of a simultaneous energy deposition corresponding to the 10B(n,alpha) reaction products in the plastic scintillator (93 keVee) and the accompanying neutron-capture gamma ray in the bismuth germanate (478 keV). Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift- register-type singles and doubles count rates. Proof-of-principle measurements were conducted with a variety of gamma-ray and neutron sources including 137Cs, 54Mn, AmLi, and 252Cf. Results of this study indicate that a neutron-capture probability of ~10% and a die-away time of ~10 ?s are possible with a 4-detector array with a detector volume of 1600 cm3. Simulations were performed that indicate neutron-capture probabilities on the order of 50% and die-away times of less than 4 ?s are realistically achievable. While further study will be required for practical application of such a detection system, the results obtained in this investigation are encouraging and may lead to a new class of high- efficiency, short die-away time neutron multiplicity counters capable of extending current non-destructive assay methods for special nuclear materials.

Miller, Michael Conrad

1997-09-01

227

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

NASA Technical Reports Server (NTRS)

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.

Hensler, J. R.

1973-01-01

228

Single channel beta-gamma coincidence system for radioxenon measurement using well-type HPGe and plastic scintillator detectors  

NASA Astrophysics Data System (ADS)

In order to improve detection sensitivity for radioxenon isotopes, a new single channel beta-gamma coincidence system has been developed. The system combines a well-type High-purity Germanium (HPGe) detector to measure gamma or X radiation and a plastic scintillator detector to obtain electron radiation. A 133Xe sample has been produced and the radioactive concentration was determined with length-compensated method based on three internal gas proportional counters. The performance of system has been checked by measuring 133Xe sample with and without coincidence. The coincidence detection efficiency of 81 keV gamma-ray from decay of 133Xe was calibrated to be 0.34 (1±2.4%), and the Minimum detectable activity (MDA) of the beta-gamma coincidence system for 133Xe was determined to be 1.8 mBq after one day of measurement.

Xie, Feng; Jiang, Wengang; Li, Xuesong; He, Xiaobing; Zhang, Jiamei; Yu, Gongshuo

2013-11-01

229

Determination of the specific alpha activity of thick sources with a large area ZnS(Ag) scintillation detector.  

PubMed

A method for determining the specific alpha activity of thick sources using a large area ZnS(Ag) scintillation detector is presented. In this method a quadratic relationship between the detector response and window thickness is assumed. This method provides a quick estimation of alpha activity in the sample, so it is an indicative method. The aim of this experimental work is to approve theoretical assumption and to develop a standard routine method for absolute alpha measurements of thick contaminated environmental sources. For this purpose reference material U(3)O(8) and spiked standards of soil were used. Measurements of contaminated soil samples from south Serbia showed the practical application of this method. PMID:17383779

Djurasevi?, M; Vukanac, I; Kandi?, A; Nadderd, L; Milosevi?, Z; Radenkovi?, M

2007-01-01

230

Development of InP solid state detector and liquid scintillator containing metal complex for measurement of pp/7Be solar neutrinos and neutrinoless double beta decay  

NASA Astrophysics Data System (ADS)

A large volume solid state detector using a semi-insulating Indium Phosphide (InP) wafer have been developed for measurement of pp/7Be solar neutrinos. Basic performance such as the charge collection efficiency and the energy resolution were measured by 60% and 20%, respectively. In order to detect two gammas (115keV and 497keV) from neutrino capture, we have designed hybrid detector which consist InP detector and liquid xenon scintillator for IPNOS experiment. New InP detector with thin electrode (Cr 50Å- Au 50Å). For another possibility, an organic liquid scintillator containing indium complex and zirconium complex were studied for a measurement of low energy solar neutrinos and neutrinosless double beta decay, respectively. Benzonitrile was chosen as a solvent because of good solubility for the quinolinolato complexes (2 wt%) and of good light yield for the scintillation induced by gamma-ray irradiation. The photo-luminescence emission spectra of InQ3 and ZrQ4 in benzonitrile was measured and liquid scintillator cocktail using InQ3 and ZrQ4 (50mg) in benzonitrile solutions (20 mL) with secondary scintillators with PPO (100mg) and POPOP (10mg) was made. The energy spectra of incident gammas were measured, and they are first results of the gamma-ray energy spectra using luminescent of metal complexes.

Fukuda, Yoshiyuki; Moriyama, Shigetaka

2012-07-01

231

Low-energy neutron detector based upon lithium lanthanide borate scintillators  

DOEpatents

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.

Czirr, John B. (Mapleton, UT)

1998-01-01

232

The neutron detectors based on oxide scintillators for control of fissionable radioactive substances  

NASA Astrophysics Data System (ADS)

A large-area X-ray CMOS image sensor (LXCIS) is widely used in mammography, non-destructive inspection, and animal CT. For LXCIS, in spite of weakness such as low spatial and energy resolution, a Indirect method using scintillator like CsI(Tl) or Gd2O2S is still well-used because of low cost and easy manufacture. A photo-diode for X-ray imaging has large area about 50 ~ 200 um as compared with vision image sensors. That is because X-ray has feature of straight and very small light emission of a scintillator. Moreover, notwithstanding several structure like columnar, the scintillator still emit a diffusible light. This diffusible light from scintillator can make spatial crosstalk in X-ray photodiode array because of a large incidence angle. Moreover, comparing with vision image sensors, X-ray sensor doesn't have micro lens for gathering the photons to photo-diode. In this study, we simulated the affection of spatial crosstalk in X-ray sensor by comparing optical sensor. Additionally, the chip, which was fabricated in 0.18 um 1P5M process by Hynix in Korea, was tested to know the effect of spatial crosstalk by changing design parameters. From these works, we found out that spatial crosstalk is affected by pixel pitch, incident angle of photons, and micro lens on each pixels.

Ryzhikov, V. D.; Grinyov, B. V.; Onyshchenko, G. M.; Piven, L. A.; Lysetska, O. K.; Opolonin, O. D.; Kostioukevitch, S. A.; Smith, C. F.

2014-09-01

233

Lead carbonate scintillator materials  

DOEpatents

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

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

1991-05-14

234

Synthesis and scintillation characterization of nanocrystalline Lu2O3(Eu) powder for high-resolution X-ray imaging detectors  

NASA Astrophysics Data System (ADS)

Lu2O3:Eu(CEu:5mol%) powder scintillators with nanocrystalline structures were successfully synthesized via a precipitation method and subsequent calcination treatment as a conversion material for X-ray imaging detectors. In this work, a homogeneous precipitation process was carried out using DEA(diethanolamine) as a precipitant to prepare nanocrystalline Eu-doped Gd2O3 powders. The microstructures, crystal structure and scintillation properties such as luminescent spectra, decay time and light intensity were measured as a function of calcination temperature in heat-treatment of the synthesized powder. The sample prepared at 1200°C calcination temperature showed the highest light intensity. And the scintillator showed a strong red emission light at near 611nm under photo- and X-ray luminescence for its potential X-ray imaging detector applications.

Cha, B. K.; Yong, S.-M.; Lee, S. J.; Kim, D. K.; Bae, J. H.; Cho, G.; Seo, C.-W.; Jeon, S.; Huh, Y.

2012-03-01

235

Development of a scintillation-fiber detector for real-time particle tracking  

NASA Astrophysics Data System (ADS)

The prototype of the OFFSET (Optical Fiber Folded Scintillating Extended Tracker) tracker is presented. It exploits a novel system for particle tracking, designed to achieve real-time imaging, large detection areas, and a high spatial resolution especially suitable for use in medical diagnostics. The main results regarding the system architecture have been used as a demonstration of the technique which has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The prototype of this tracker, presented in this paper, has a 20 × 20 cm2 sensitive area, consisting of two crossed ribbons of 500 micron square scintillating fibers. The track position information is extracted in real time in an innovative way, using a reduced number of read-out channels to obtain very large detection area with moderate enough costs and complexity. The performance of the tracker was investigated using beta sources, cosmic rays, and a 62 MeV proton beam.

Lo Presti, D.; Bonanno, D. L.; Longhitano, F.; Pugliatti, C.; Russo, G. V.; Aiello, S.; Cirrone, G. A. P.; Giordano, V.; Leonora, E.; Randazzo, N.; Romano, F.; Russo, M.; Sipala, V.; Stancampiano, C.; Reito, S.

2013-04-01

236

Proton transfer bis-benzazole fluors and their use in scintillator detectors  

DOEpatents

A novel class of proton transfer, bis-benzazole, fluorescent compounds, i.e., fluors, is disclosed. The novel fluors include substituted or unsubstituted 1,4-bis(2-benzazolyl)-2-hydroxybenzenes and 1,4-bis(2-benzazolyl)-2-amidobenzenes wherein the benzazolyl group may be benzoxazolyl, benzimidazolyl, benzothiazolyl, and the like. The benzazolyl groups may be substituted with one or more alkyl groups to improve solubility in organic matrix materials such as solvents, monomers, resins, polymers, and the like. The novel fluors may be used in the manufacture of fluorescent coatings, objects, scintillators, light sources and the like. The novel fluors are particularly useful for radiation-hard, solid scintillators for the detection and measurement of high energy particles and radiation.

Kauffman, J.M.

1994-03-29

237

Proton transfer bis-benzazole fluors and their use in scintillator detectors  

DOEpatents

A novel class of proton transfer, bis-benzazole, fluorescent compounds, i.e., fluors, is disclosed. The novel fluors include substituted or unsubstituted 1,4-bis(2-benzazolyl)-2-hydroxybenzenes and 1,4-bis(2-benzazolyl)-2-amidobenzenes wherein the benzazolyl group may be benzoxazolyl, benzimidazolyl, benzothiazolyl, and the like. The benzazolyl groups may be substituted with one or more alkyl groups to improve solubility in organic matrix materials such as solvents, monomers, resins, polymers, and the like. The novel fluors may be used in the manufacture of fluorescent coatings, objects, scintillators, light sources and the like. The novel fluors are particularly useful for radiation-hard, solid scintillators for the detection and measurement of high energy particles and radiation.

Kauffman, Joel M. (Wayne, PA)

1994-01-01

238

Calorimeter prototype based on silicon drift detectors coupled to scintillators for Compton telescopes application  

Microsoft Academic Search

The project of a new calorimeter module for Compton telescopes based on an ar- ray of silicon drift detectrors (SDD) coupled to thallium activated cesium iodide (CsI(Tl)) scintillating crystals is presented. Because of their low output capacitance and the possibility to have the rst amplifying stage directly integrated on chip, SDDs show better noise performances than traditional p-intrinsic-n (PIN) photodi-

M. Marisaldi; C. Labanti; A. Bulgarelli; E. Celesti; G. Di Cocco; F. Gianotti; A. Mauri; E. Rossi; A. Traci; M. Trifoglio

2003-01-01

239

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

Microsoft Academic Search

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

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

1998-01-01

240

Cosmic Ray Measurements by Scintillators with Metal Resistor Semiconductor Avalanche Photo Diodes  

ERIC Educational Resources Information Center

An educational set-up for cosmic ray physics experiments is described. The detector is based on scintillator tiles with a readout through metal resistor semiconductor (MRS) avalanche photo diode (APD) arrays. Typical measurements of the cosmic angular distribution at sea level and a study of the East-West asymmetry obtained by such a device are…

Blanco, Francesco; La Rocca, Paola; Riggi, Francesco; Akindinov, Alexandre; Mal'kevich, Dmitry

2008-01-01

241

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

PubMed Central

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. PMID:24089917

Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C.

2013-01-01

242

First-principles studies of Ce and Eu doped inorganic materials as candidates for scintillator gamma ray detectors  

NASA Astrophysics Data System (ADS)

We have performed high-throughput DFT based (GGA+U) band structure calculations for new Ce and Eu doped wide band gap inorganic materials to determine their potential as candidates for gamma ray scintillator detectors. These calculations are based on determining the 4f ground state level of the Ce and Eu relative to the valence band of the host as well as the position of the Ce and Eu 5d excited state relative to the conduction band of the host. We find many classes of candidate materials where the 5d is in the conduction band preventing scintillation. Even when the Eu and Ce 4f and 5d levels are placed well in the gap of the host, traps on the host can also prevent the energy of the gamma ray transferring to the Eu or Ce. We therefore also performed calculations for host hole traps and electron traps to compare their energies to the Ce and Eu 4f and 5d levels.

Canning, Andrew; Chourou, Slim; Derenzo, Stephen

2012-02-01

243

Hybrid gas scintillation proportional counter/phoswich detector for hard X-ray astronomy  

NASA Technical Reports Server (NTRS)

A concept is presented for a balloon-borne imaging hybrid proportional counter/phoswich detector of medium to hard X-rays. The phoswich would be optically coupled to the exit window of the proportional counter, and both detectors would use a common position-sensitive readout. It is anticipated that such a detector could combine the good energy and position resolution and excellent background rejection ability of the proportional counter for incident photon energies less than 100 keV with the extended response of the phoswich for higher energies. The phoswich could also be used to reject Compton scattering events in the proportional counter. This detector concept is studied using numerical simulations of a 400 sq cm square prototype detector. Results from this simulation indicate that current levels of proportional counter and phoswich performance are attainable at small cost in quantum efficiency, compared to a bare phoswich detector.

Grindlay, Jonathan E.; Manandhar, Raj P.

1989-01-01

244

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

NASA Astrophysics Data System (ADS)

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.

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

245

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

PubMed Central

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

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

2014-01-01

246

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

247

Characterization of a scintillating mini-detector for time-of-flight positron emission tomography with depth-of-interaction.  

PubMed

By exploiting a suitable treatment of the scintillator surfaces, along with silicon photomultiplier photodetectors and specific algorithms for raw data analysis, we achieved a remarkable tradeoff between energy, time, and depth-of-interaction (DOI) resolution, thus supporting the feasibility of a prostate time-of-flight positron emission tomography probe, magnetic resonance imaging compatible, with the required features and performance. In numbers this means a detector element of 1.5 mm × 1.5 mm × 10 mm, promising to achieve at the same time energy resolution around 11.5%, coincidence resolving time around 300 ps corresponding to a space resolution <5 cm along the line of response, and DOI resolution even below 1 mm. We stress that such a time resolution allows to increase significantly the noise equivalent counting rate, and consequently improve the image quality and the lesion detection capability. PMID:22938315

Cosentino, Luigi; Finocchiaro, Paolo; Pappalardo, Alfio; Garibaldi, Franco

2012-08-01

248

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

NASA Astrophysics Data System (ADS)

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.

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

249

High-position-resolution neutron imaging detector with crossed wavelength shifting fiber read-out using two ZnS/ 6LiF scintillator sheets  

NASA Astrophysics Data System (ADS)

High-intensity pulsed neutron sources have made a great deal of progress in Japan (J-PARC project), the United States (SNS project), and the United Kingdom (ISIS-II project). The specifications required for neutron imaging detectors used at these facilities are a high-position resolution, a high-detection efficiency, a high counting rate, a high n/? ratio, etc. Especially the detectors which exhibit a high-position resolution and high detection efficiency are required for the crystallography diffractometers. It is also essential for these detectors to be compact and to have the least dead-detection area for a large solid-angle coverage. We have developed a compact high-position-resolution neutron-imaging detector with wavelength shifting (WLS) fibers using two scintillator sheets. The developed detector structure ensures compactness and easy assembly of these types of detectors. It was confirmed that the neutron imaging detector using WLS fibers with a size of 0.5×0.5 mm exhibited a position resolution of less than 0.8 mm. The detection efficiency for thermal neutrons was improved 55% by using the two scintillator sheets from 29% by the single sheet.

Katagiri, M.; Nakamura, T.; Ebine, M.; Birumachi, A.; Sato, S.; Shooneveld, E. M.; Rhodes, N. J.

2007-04-01

250

Neutron-sensitive ZnS/10B2O3 ceramic scintillator detector as an alternative to a 3He-gas-based detector for a plutonium canister assay system  

NASA Astrophysics Data System (ADS)

A neutron-sensitive ZnS/10B2O3 ceramic scintillator detector was developed as an alternative to a 3He-gas-based detector for use in a plutonium canister assay system. The detector has a modular structure, with a flat ZnS/10B2O3 ceramic scintillator strip that is installed diagonally inside a light-reflecting aluminium case with a square cross-section, and where the scintillation light is detected using two photomultiplier tubes attached at both ends of the case. The prototype detectors, which have a neutron-sensitive area of 30 mm×250 mm, exhibited a sensitivity of 21.7-23.4±0.1 cps/nv (mean±SD) for thermal neutrons, a 137Cs gamma-ray sensitivity of 1.1-1.9±0.2×10-7 and a count variation of less than 6% over the detector length. A trial experiment revealed a temperature coefficient of less than -0.24±0.05%/°C over the temperature range of 20-50 °C. The detector design and the experimental results are presented.

Nakamura, T.; Ohzu, A.; Toh, K.; Sakasai, K.; Suzuki, H.; Honda, K.; Birumachi, A.; Ebine, M.; Yamagishi, H.; Takase, M.; Haruyama, M.; Kureta, M.; Soyama, K.; Nakamura, H.; Seya, M.

2014-11-01

251

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

PubMed Central

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

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

2014-01-01

252

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

PubMed

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

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

2014-01-01

253

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

PubMed Central

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

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

2011-01-01

254

hybridMANTIS: a CPU-GPU Monte Carlo method for modeling indirect x-ray detectors with columnar scintillators.  

PubMed

The computational modeling of medical imaging systems often requires obtaining a large number of simulated images with low statistical uncertainty which translates into prohibitive computing times. We describe a novel hybrid approach for Monte Carlo simulations that maximizes utilization of CPUs and GPUs in modern workstations. We apply the method to the modeling of indirect x-ray detectors using a new and improved version of the code MANTIS, an open source software tool used for the Monte Carlo simulations of indirect x-ray imagers. We first describe a GPU implementation of the physics and geometry models in fastDETECT2 (the optical transport model) and a serial CPU version of the same code. We discuss its new features like on-the-fly column geometry and columnar crosstalk in relation to the MANTIS code, and point out areas where our model provides more flexibility for the modeling of realistic columnar structures in large area detectors. Second, we modify PENELOPE (the open source software package that handles the x-ray and electron transport in MANTIS) to allow direct output of location and energy deposited during x-ray and electron interactions occurring within the scintillator. This information is then handled by optical transport routines in fastDETECT2. A load balancer dynamically allocates optical transport showers to the GPU and CPU computing cores. Our hybridMANTIS approach achieves a significant speed-up factor of 627 when compared to MANTIS and of 35 when compared to the same code running only in a CPU instead of a GPU. Using hybridMANTIS, we successfully hide hours of optical transport time by running it in parallel with the x-ray and electron transport, thus shifting the computational bottleneck from optical tox-ray transport. The new code requires much less memory than MANTIS and, asa result, allows us to efficiently simulate large area detectors. PMID:22469917

Sharma, Diksha; Badal, Andreu; Badano, Aldo

2012-04-21

255

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

PubMed Central

The plastic scintillation detectors (PSD) have many advantages over other detectors in small field dosimetry due to its high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs will undergo a quenching effect which makes the signal level reduced significantly when the detector is close to Bragg peak where the linear energy transfer (LET) for protons is very high. This study measures the quenching correction factor (QCF) for a PSD in clinical passive-scattering proton beams and investigates the feasibility of using PSDs in depth-dose measurements in proton beams. A polystyrene based PSD (BCF-12, ?0.5mm×4mm) was used to measure the depth-dose curves in a water phantom for monoenergetic unmodulated proton beams of nominal energies 100, 180 and 250 MeV. A Markus plane-parallel ion chamber was also used to get the dose distributions for the same proton beams. From these results, the QCF as a function of depth was derived for these proton beams. Next, the LET depth distributions for these proton beams were calculated by using the MCNPX Monte Carlo code, based on the experimentally validated nozzle models for these passive-scattering proton beams. Then the relationship between the QCF and the proton LET could be derived as an empirical formula. Finally, the obtained empirical formula was applied to the PSD measurements to get the corrected depth-dose curves and they were compared to the ion chamber measurements. A linear relationship between QCF and LET, i.e. Birks' formula, was obtained for the proton beams studied. The result is in agreement with the literature. The PSD measurements after the quenching corrections agree with ion chamber measurements within 5%. PSDs are good dosimeters for proton beam measurement if the quenching effect is corrected appropriately. PMID:23128412

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

2013-01-01

256

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

NASA Astrophysics Data System (ADS)

Plastic scintillation detectors (PSDs) have many advantages over other detectors in small field dosimetry due to their high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs undergo a quenching effect which makes the signal level reduced significantly when the detector is close to the Bragg peak where the linear energy transfer (LET) for protons is very high. This study measures the quenching correction factor (QCF) for a PSD in clinical passive-scattering proton beams and investigates the feasibility of using PSDs in depth-dose measurements in proton beams. A polystyrene-based PSD (BCF-12, ?0.5 mm × 4 mm) was used to measure the depth-dose curves in a water phantom for monoenergetic unmodulated proton beams of nominal energies 100, 180 and 250 MeV. A Markus plane-parallel ion chamber was also used to get the dose distributions for the same proton beams. From these results, the QCF as a function of depth was derived for these proton beams. Next, the LET depth distributions for these proton beams were calculated by using the MCNPX Monte Carlo code, based on the experimentally validated nozzle models for these passive-scattering proton beams. Then the relationship between the QCF and the proton LET could be derived as an empirical formula. Finally, the obtained empirical formula was applied to the PSD measurements to get the corrected depth-dose curves and they were compared to the ion chamber measurements. A linear relationship between the QCF and LET, i.e. Birks' formula, was obtained for the proton beams studied. The result is in agreement with the literature. The PSD measurements after the quenching corrections agree with ion chamber measurements within 5%. PSDs are good dosimeters for proton beam measurement if the quenching effect is corrected appropriately.

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

2012-12-01

257

New application of scintillator ZnSe(Te) in scintielectronic detectors for detection of neutrons, medical imaging, explosive detection, and NDT  

NASA Astrophysics Data System (ADS)

Scintillators on the basis of AIIBVI compounds, such as ZnSe(Te), can be used for detection of secondary charged particles coming from nuclear reactions in which neutrons interact with target nuclei of atoms present in transparent materials of dispersion scintillation detectors matrices. Using unique properties of scintillator ZnSe(Te) we show possibility of increase detection efficiency for soft x-ray radiation (20 - 90 keV). The amorphous silicon flat panels and the photodiode arrays wide used for non-destructive testing and medical imaging (spatial resolution 20 - 400 mkm). By our estimations, using of such detectors in combination with thin film of ZnSe(Te) can increase efficiency of registration of x-ray radiation (for the source of 60-140kV) in 1,2 - 2 times. We obtained thin films (10-450mkm) of scintillator ZnSe(Te) on the different substrate materials and estimated the relative light yield of the layers deposited on the graphite and Al2O3 ceramic substrates and the bulk ZnSe(Te) crystal. Use of ZnSe(Te) in the low-energy "scintillator - photodiode" type detector allowed to increase accuracy of authentication of explosives (HEIMANN X-RAY INSPECTION SYSTEM EDtS10080). Using the dual energy digital radiography system prototype we obtained the x-ray images (60 projections of each object). These images are basic data for computer tomography and three-dimensional reconstruction of density and effective atomic number. The color identification palette provides clearly show variations of effective atomic number in biological and inorganic objects. So, for example, changes of calcium concentration in a bone. The research described in this publication was supported by STCU #4115 and NATO SfP-982823.

Ryzhikov, Volodymyr D.; Opolonin, Oleksandr D.; Fedorov, Alexander G.; Lysetska, Olena K.; Kostioukevitch, Sergey A.

2008-08-01

258

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

SciTech Connect

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.

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

259

Digital processing of signals from LaBr3:Ce scintillation detectors  

NASA Astrophysics Data System (ADS)

In this paper, we report on the results of digital signal processing of LaBr3(Ce) detectors. The photomultiplier (PMT) output signals from two cylindrical LaBr3(Ce) detectors (1.5'' diameter and 2'' tall) were directly digitized with an ultrafast digitizer (sampling rate up to 4 GSample/s and 10-bits resolution) and the energy and timing information were extracted through offline analysis of the pulses. It is shown that at high sampling rates (4 GS/s) a simple integration of pulses is sufficient to reproduce the analogue energy resolution of the detectors (3.5% at 662 keV energy) and by employing a digital version of constant-fraction discrimination (CFD) timing a time resolution of 240 ps (FWHM) is achieved at the energy lines of 60Co. The effects of pulse sampling rate were studied, indicating a degradation of the performance of the detectors with reducing the pulse sampling rate. In particular, it was found that at sampling rates below 1 GS/s, the digital timing can be limited by the aliasing error. By using an anti-aliasing filter, a time resolution of 375 ps (FWHM) and an energy resolution of 3.5% at 662 keV were achieved with a sampling rate of 500 MS/s.

Nakhostin, M.; Podolyak, Zs; Regan, P. H.

2014-12-01

260

SCINTILLA A European project for the development of scintillation detectors and new technologies for nuclear security  

E-print Network

Europe monitors transits using radiation detectors to prevent illicit trafficking of nuclear materials. The SCINTILLA project aims to develop a toolbox of innovative technologies designed to address different usage cases. This article will review the scope, approach, results of the first benchmark campaign and future plans of the SCINTILLA project.

A. Alemberti; M. Battaglieri; E. Botta; R. De Vita; E. Fanchini; G. Firpo

2014-04-14

261

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

SciTech Connect

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.

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

262

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

PubMed Central

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

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

2009-01-01

263

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

PubMed

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

Mondal, Nagendra Nath

2009-10-01

264

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

PubMed Central

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 (Lu2SiO5: Ce in short LSO), Barium Fluoride (BaF2) and BriLanCe 380 (Cerium doped Lanthanum tri-Bromide, in short LaBr3) 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 BaF2 and LaBr3, 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

Mondal, Nagendra Nath

2009-01-01

265

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

NASA Astrophysics Data System (ADS)

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.

Carroll, Lewis

2014-02-01

266

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

PubMed Central

Purpose: This work presents the experimental extraction of the overall perturbation factor PQ in megavoltage electron beams for NACP-02 and Roos parallel-plate ionization chambers using a plastic scintillation detector (PSD). Methods: The authors used a single scanning PSD mounted on a high-precision scanning tank to measure depth-dose curves in 6, 12, and 18 MeV clinical electron beams. The authors also measured depth-dose curves using the NACP-02 and PTW Roos chambers. Results: The authors found that the perturbation factors for the NACP-02 and Roos chambers increased substantially with depth, especially for low-energy electron beams. The experimental results were in good agreement with the results of Monte Carlo simulations reported by other investigators. The authors also found that using an effective point of measurement (EPOM) placed inside the air cavity reduced the variation of perturbation factors with depth and that the optimal EPOM appears to be energy dependent. Conclusions: A PSD can be used to experimentally extract perturbation factors for ionization chambers. The dosimetry protocol recommendations indicating that the point of measurement be placed on the inside face of the front window appear to be incorrect for parallel-plate chambers and result in errors in the R50 of approximately 0.4 mm at 6 MeV, 1.0 mm at 12 MeV, and 1.2 mm at 18 MeV. PMID:20879593

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

2010-01-01

267

Upgrade of the POLDI diffractometer with a ZnS(Ag)/6LiF scintillation detector read out with WLS fibers coupled to SiPMs  

NASA Astrophysics Data System (ADS)

A thermal neutron detector based on ZnS(Ag)/6LiF scintillator, wavelength- shifting fibers (WLS) and silicon photomultipliers (SiPM) is under development at the Paul Scherrer Institute (PSI) for upgrading the POLDI instrument, a pulse-overlap diffractometer. The design of the detector is outlined, and the measurements performed on a single channel prototype are presented. An innovative signal processing system based on a photon counting approach is under development. Its principle of operation is described and its performances are evaluated on the basis of a Monte Carlo simulation.

Mosset, J.-B.; Stoykov, A.; Davydov, V.; Hildebrandt, M.; Van Swygenhoven, H.; Wagner, W.

2014-07-01

268

Background reduction in neutrinoless double beta decay experiments using segmented detectors—A Monte Carlo study for the GERDA setup  

NASA Astrophysics Data System (ADS)

The identification of gamma radiation is essential for a new generation of double beta decay experiments. The GERmanium Detector Array, GERDA, located at the INFN Gran Sasso National Laboratory (LNGS) in Italy, uses germanium, enriched in Ge76, as source and detector, and aims at a background level of less than 10-3 counts/(kg keV y) in the region of the Q-value. For the first time highly segmented detectors will be installed in a double beta decay experiment. A detailed GEANT4 Monte Carlo study was performed to evaluate the background reduction achievable by anti-coincidence cuts between crystals and segments. Within the overall geometry of GERDA, the segmentation scheme considered here provides around an order of magnitude of extra background reduction.

Abt, I.; Altmann, M.; Caldwell, A.; Kröninger, K.; Liu, X.; Majorovits, B.; Pandola, L.; Tomei, C.

2007-01-01

269

Thin-film scintillators for extended ultraviolet /UV/ response silicon detectors  

NASA Technical Reports Server (NTRS)

The preparation and radiometric properties of silicon detectors coated with fluorescent thin films are described. The films are deposited from solutions of clear plastics, such as acrylic resins, polyvinyl toluene or polystyrene, and of organic laser dyes in a common solvent. They are optically clear, mechanically and chemically stable, yet easily applied and removed. Multiple doped films of a few microns thickness exhibit broad-band absorption from less than 250 nm to about 450 nm and narrow band emissions with peaks ranging from 380 nm to 600 nm. Internal quantum efficiencies are close to 100 percent and fluorescence decay times are in the nanosecond range. When deposited on optically denser media, a large fraction of the fluorescent emission is trapped in the substrate. Silicon photodiodes coated with multiple doped films exhibit high external quantum efficiencies and virtually flat photon response in the near UV.

Viehmann, W.

1979-01-01

270

Avalanche Photodiode for liquid xenon scintillation: quantum efficiency and gain  

NASA Astrophysics Data System (ADS)

We report on measurements with a large area, silicon Avalanche Photodiode (APD) as photodetector for the ultraviolet scintillation light of liquid xenon (LXe) at temperatures between 167 and 188 K. The maximum gain of the APD for the scintillation light from a 210Po ?-source in LXe was 5.3 × 103. Based on the geometry of the setup, the quantum efficiency of the APD was measured at 34% ± 5% at the mean scintillation wavelength of 178 nm. The high quantum efficiency and high gain of the APD make it an attractive alternative UV photon sensor to PMTs for LXe detectors, especially for experiments requiring high light yields, such as dark matter searches for Weakly Interacting Massive Particles, or a Compton telescope in MeV ?-ray astronomy.

Shagin, P.; Gomez, R.; Oberlack, U.; Cushman, P.; Sherwood, B.; McClish, M.; Farrell, R.

2009-01-01

271

Development of a scintillating G-GEM detector for a 6-MeV X-band Linac for medical applications  

NASA Astrophysics Data System (ADS)

We recently developed glass gas electron multipliers (G-GEMs) with an entirely new process using photo-etchable glass. The photo-etchable glass used for the substrate is called PEG3 (Hoya Corporation). Taking advantage of low outgassing material, we have envisioned a medical application of G-GEMs. A two-dimensional position-sensitive dosimetry system based on a scintillating gas detector is being developed for real-time dose distribution monitoring in X-ray radiation therapy. The dosimetry system consists of a chamber filled with an Ar/CF4 scintillating gas mixture, inside of which G-GEM structures are mounted. Photons produced by the excited Ar/CF4 gas molecules during the gas multiplication in the GEM holes are detected by a mirror-lens-CCD-camera system. We found that the intensity distribution of the measured light spot is proportional to the 2D dose distribution. In this work, we report on the first results from a scintillating G-GEM detector for a position-sensitive X-ray beam dosimeter.

Fujiwara, T.; Tanaka, S.; Mitsuya, Y.; Takahashi, H.; Tagi, K.; Kusano, J.; Tanabe, E.; Yamamoto, M.; Nakamura, N.; Dobashi, K.; Tomita, H.; Uesaka, M.

2013-12-01

272

Characterization of the SIDDHARTA-2 second level trigger detector prototype based on scintillators coupled to a prism reflector light guide  

NASA Astrophysics Data System (ADS)

The SIDDHARTA experiment at the DA?NE collider of LNF-INFN performed in 2009 high precision measurements of kaonic hydrogen and kaonic helium atomic transitions. To determine the bar KN isospin dependent scattering lenghts an important measurement, namely the kaonic deuterium one, is, however, still missing. Due to the very low expected yield of the kaonic deuterium K? transition, a major improvement in the signal over background ratio is needed. To achieve a further background reduction, a second level trigger, based on the detection of charged pions produced by the K- absorption on various materials, including the target gas nuclei, is planned to be implemented in the future SIDDHARTA-2 experiment. For shielding-related geometrical limitations, a single side of the scintillators can be accessed; in order to reach a good time resolution and uniform efficiency, a both-end readout was then realized with complex multi-reflection light guides. In this work, the results of the tests made on a detector prototype, performed on the ?M-1 beamline of the Paul Scherrer Institute (Switzerland), are presented. The tests had the goal to determine the efficiency and the time resolution for pions, which should comply with the minimum required values of 90% and 1 ns (FWHM) respectively. The obtained results, 96% efficiency and 750 ps FWHM for 170 MeV/c momentum pions, qualify the prototype as an excellent second level trigger for the SIDDHARTA-2 experiment. Similar results for 170 MeV/c momentum muons and electrons are also presented.

Bazzi, M.; Berucci, C.; Curceanu, C.; d'Uffizi, A.; Iliescu, M.; Sbardella, E.; Scordo, A.; Shi, H.; Sirghi, F.; Tatsuno, H.; Tucakovic, I.

2013-11-01

273

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

PubMed Central

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

Bircher, Chad

2012-01-01

274

LaCl 3(Ce) scintillation detector applications for environmental gamma-ray measurements of low to high dose rates  

NASA Astrophysics Data System (ADS)

A new cerium-doped LaCl 3(Ce) scintillator is evaluated with respect to the application in environmental gamma-ray dosimetry and spectrometry. The scintillator is very attractive for gamma-ray spectrometry in the case of high count rate, because it has excellent energy resolution and fast decay time. The performance characteristics of a scintillator with a 25.4 mm×25.4 mm LaCl 3(Ce) crystal are studied and compared to those of a NaI(Tl) scintillator with the same size crystal. Acquired pulse height spectra are converted to dose rates by using the G(E) function method. Though the LaCl 3(Ce) crystal itself produces a rather high background in the crystal itself, the scintillator provides good energy information and dose-rate readings from low to high-level (several mGy/h) by subtracting the self-background. The properties of LaCl 3(Ce) scintillator suggest that the scintillator could be a promising candidate for monitoring at high dose levels as in emergencies, as well as at ordinary levels of background radiation.

Tsutsumi, Masahiro; Tanimura, Yoshihiko

2006-02-01

275

Setup and calibration of a position sensitive microchannel plate detector and analysis of a test run optimizing the WITCH experiment  

E-print Network

The standard model of particle physics only implies vectorial and axial-vectorial currents. Symmetry considerations allow for additional, exotic currents, too. Experimentally these are ruled out only to a percent level. The so-called beta-neutrino angular correlation coefficient 'a' is a parameter who’s value strongly depends on the underlying interaction types. An indirect method for its determination is the measurement of the recoil energy spectrum of the daughter nuclei after beta decay. The shape of the spectrum is dependent on the value of a. The WITCH collaboration aims to determine 'a' with a relative precision of 0.5% from a measurement of the recoil energy spectrum of the 35Ar decay. For this purpose 35Ar+ ions are stored in a Penning trap and the recoil energy of the daughter nuclei will be determined by means of a retardation spectrometer with magnetic adiabatic collimation (MAC-E filter). To detect the recoil ions a position sensitive microchannel plate detector (MCP detector) is used. In this ...

Friedag, Peter

276

Position and energy resolution of a new gamma-ray detector based on a single CsI(Tl) scintillator coupled to a silicon drift chamber array  

SciTech Connect

The authors have developed a first prototype of gamma-ray detector for imaging and spectroscopy which is based on a single CsI(Tl) scintillator coupled to a linear array of Silicon Drift Chambers (SDCs). The detector performs the measurement of the position of interaction in one coordinate, by the centroid method, and the measurement of the {gamma} photon energy, by summing the signals of all the single units. The small size and the compactness of the CsI(Tl)-SDC assembly make this detector scheme an interesting solution for the realization of small scintillation cameras for nuclear medicine. Moreover, the low electronics noise offered by the SDC allows good performance in both position and energy resolution. The first experimental results obtained on the prototype are reported in this work. A position resolution better than 1 mm FWHM and an energy resolution of about 16% FWHM at 122 keV have been measured. A comparison of the experimental results with the results of Monte Carlo simulations is also reported.

Fiorini, C.; Longoni, A. [Politecnico di Milano (Italy). Dipt. di Elettronica e Informazione] [Politecnico di Milano (Italy). Dipt. di Elettronica e Informazione; Perotti, F. [C.N.R., Milano (Italy). Ist. di Fisica Cosmica e Technologies Relative] [C.N.R., Milano (Italy). Ist. di Fisica Cosmica e Technologies Relative; Labanti, C.; Rossi, E. [C.N.R., Bologna (Italy). Ist. di Tecnologie e Studio delle Radiazioni Extraterrestri] [C.N.R., Bologna (Italy). Ist. di Tecnologie e Studio delle Radiazioni Extraterrestri

1999-08-01

277

Scintillation properties of SrI_2(Eu^2+) (Strontium iodide doped with europium) for high energy astrophysical detectors: Nonproportionality as a function of temperature and at high gamma-ray energies  

E-print Network

Strontium iodide doped with europium is a new scintillator material being developed as an alternative to lanthanum bromide doped with cerium for use in high energy astrophysical detectors. As with all scintillators, the issue of nonproportionality is important because it affects the energy resolution of the detector. In this study, we investigate how the nonproportionality of strontium iodide doped with europium changes as a function of temperature 16 deg. C to 60 deg. C by heating the strontium iodide doped with europium scintillator separate from the photomultiplier tube. In a separate experiment, we also investigate the nonproportionality at high energies (up to 6 MeV) of strontium iodide doped with europium at a testing facility located at NASA Goddard Space Flight Center. We find that the nonproportionality increases nearly monotonically as the temperature of the strontium iodide doped with europium scintillator is increased, although there is evidence of non-monotonic behavior near 40 deg. C, perhaps du...

Perea, R S; Groza, M; Caudel, D; Nowicki, S; Burger, A; Stassun, K G; Peterson, T E

2014-01-01

278

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

SciTech Connect

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.

Taheri, A., E-mail: at1361@aut.ac.ir; Saramad, S.; Ghalenoei, S.; Setayeshi, S. [Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran 15875-4413 (Iran, Islamic Republic of)] [Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran 15875-4413 (Iran, Islamic Republic of)

2014-01-15

279

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

SciTech Connect

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.

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

280

Real-time, digital pulse-shape discrimination in non-hazardous fast liquid scintillation detectors: Prospects for safety and security  

SciTech Connect

Pulse-shape discrimination (PSD) in fast, organic scintillation detectors is a long-established technique used to separate neutrons and {gamma} rays in mixed radiation fields. In the analogue domain the method can achieve separation in real time, but all knowledge of the pulses themselves is lost thereby preventing the possibility of any post- or repeated analysis. Also, it is typically reliant on electronic systems that are largely obsolete and which require significant experience to set up. In the digital domain, PSD is often more flexible but significant post-processing has usually been necessary to obtain neutron/{gamma}-ray separation. Moreover, the scintillation media on which the technique relies usually have a low flash point and are thus deemed hazardous. This complicates the ease with which they are used in industrial applications. In this paper, results obtained with a new portable digital pulse-shape discrimination instrument are described. This instrument provides real-time, digital neutron/{gamma} separation whilst preserving the synchronization with the time-of-arrival for each event, and realizing throughputs of 3 x 10{sup 6} events per second. Furthermore, this system has been tested with a scintillation medium that is non-flammable and not hazardous. (authors)

Joyce, M. J. [Engineering Dept., Lancaster Univ., Lancaster, LA1 4YR (United Kingdom); Aspinall, M. D.; Cave, F. D. [Hybrid Instruments Ltd., Lancaster LA1 1XB (United Kingdom); Lavietes, A. D. [Dept. of Safeguards, International Atomic Energy Agency, A-1400 Vienna (Austria)

2011-07-01

281

3D Printing of Scintillating Materials  

E-print Network

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.

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

2014-01-01

282

3D Printing of Scintillating Materials  

E-print Network

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.

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

2014-06-15

283

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

SciTech Connect

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 6x6 array of 1.5x1.5 mm{sup 2} macro-pixels, each containing a 36x36 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.

Prekas, G.; Breen, M.; Sabet, H.; Bhandari, H.; Derderian, G.; Robertson, F. Jr; Stapels, C. J.; Christian, J.; Cool, S.; Nagarkar, V. V. [Radiation Monitoring Devices, Inc., 44 Hunt Street, Watertown, Massachusetts 02472 (United States)

2011-12-13

284

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)

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.

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

1985-01-01

285

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

NASA Astrophysics Data System (ADS)

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.

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

2013-02-01

286

Nuclear Resonance Fluorescence of 235U Measured with High-Resolution LaBr3(Ce) Scintillation Detectors  

NASA Astrophysics Data System (ADS)

A nuclear resonance fluorescence (NRF) experiment was performed on a 235U target with quasi-monochromatic ?-rays at the High Intensity ?-ray Source (HI?S) facility using a 1733 keV resonant energy. A LaBr3(Ce) detector array consisting of eight cylindrical detectors, each with a length of 7.62 cm and a diameter of 3.81 cm, was implemented in this measurement. Moreover, a high-purity germanium (HPGe) detector array consisting of four detectors, each of which has a relative efficiency of 60%, was used as the benchmark for the measurement taken using the LaBr3(Ce) detector array. The integrated cross section of the NRF level, measured with LaBr3(Ce) detectors, showed good agreement with the available data.

Omer, Mohamed; Negm, Hani; Zen, Heishun; Daito, Izuru; Kii, Toshiteru; Masuda, Kai; Ohgaki, Hideaki; Hajima, Ryoichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Kikuzawa, Nobuhiro

2013-10-01

287

Scintillator fiber optic long counter  

DOEpatents

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.

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

1994-01-01

288

Measurement and analysis of the Am241(n,?) cross section with liquid scintillator detectors using time-of-flight spectroscopy at the n_TOF facility at CERN  

NASA Astrophysics Data System (ADS)

The Am241(n,?) cross section has been measured at the n_TOF facility at CERN using deuterated benzene liquid scintillators, commonly known as C6D6 detectors, and time-of-flight spectrometry. The results in the resolved resonance range bring new constraints to evaluations below 150 eV, and the energy upper limit was extended from 150 to 320 eV with a total of 172 new resonances not present in current evaluations. The thermal capture cross section was found to be ?th=678±68 b, which is in good agreement with evaluations and most previous measurements. The capture cross section in the unresolved resonance region was extracted in the remaining energy range up to 150 keV, and found to be larger than current evaluations and previous measurements.

Fraval, K.; Gunsing, F.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Barbagallo, M.; Bécares, V.; Be?vá?, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Duran, I.; Dressler, R.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Ganesan, S.; García, A. R.; Giubrone, G.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Gurusamy, P.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Krti?ka, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Leong, L. S.; Losito, R.; Mallick, A.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondalaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Robles, M. S.; Roman, F.; Rubbia, C.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J. L.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T.; Žugec, P.; n TOF Collaboration

2014-04-01

289

DETECTORS AND EXPERIMENTAL METHODS: Measurement of the response function and the detection efficiency of an organic liquid scintillator for neutrons between 1 and 30 MeV  

NASA Astrophysics Data System (ADS)

The light output function of a varphi50.8 mm × 50.8 mm BC501A scintillation detector was measured in the neutron energy region of 1 to 30 MeV by fitting the pulse height (PH) spectra for neutrons with the simulations from the NRESP code at the edge range. Using the new light output function, the neutron detection efficiency was determined with two Monte-Carlo codes, NEFF and SCINFUL. The calculated efficiency was corrected by comparing the simulated PH spectra with the measured ones. The determined efficiency was verified at the near threshold region and normalized with a Proton-Recoil-Telescope (PRT) at the 8-14 MeV energy region.

Huang, Han-Xiong; Ruan, Xi-Chao; Chen, Guo-Chang; Zhou, Zu-Ying; Li, Xia; Bao, Jie; Nie, Yang-Bo; Zhong, Qi-Ping

2009-08-01

290

An evaluation of the response of a scintillation detector for estimating the radionuclide composition of a contaminated cloud.  

PubMed

We have made Monte Carlo calculations of the scintillation spectrometer response for the photon field from a cloud of contaminated air after selected scenarios of a nuclear power plant accident. Calculations (using MCNP5 code-X-5 Monte Carlo Team, 2005) were performed for 36 main energy lines of the expected radionuclides. The evaluated spectra enable us to simulate real composite spectra and their evolution in time, and to assess the applicability of a specific spectrometry system for a semi-qualitative and semi-quantitative analysis of the composition of the cloud. PMID:19897376

Kluson, J; Cechák, T; Kuca, P; H?lka, J

2010-01-01

291

Extruding plastic scintillator at Fermilab  

SciTech Connect

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

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

2003-10-31

292

Nanophosphor composite scintillator with a liquid matrix  

DOEpatents

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

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

2010-03-16

293

Scintillator materials containing lanthanum fluorides  

DOEpatents

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.

Moses, W.W.

1991-05-14

294

A scintillator-based detector with sub-100-?m spatial resolution comprising a fibre-optic taper with wavelength-shifting fibre readout for time-of-flight neutron imaging  

NASA Astrophysics Data System (ADS)

A scintillator-based neutron-counting imaging detector with a sub-100-?m spatial resolution was developed for energy-selective neutron imaging. The detector head of the detector comprised a thin ZnS/6LiF scintillator screen, a fibre-optic taper and crossed wavelength-shifting (WLS) fibre arrays. A high spatial resolution was achieved by constructing the scintillator with a thickness of 100 ?m and placing it in contact with the fibre-optic taper at a magnification ratio of 3.1:1. WLS fibres with a diameter of 100±5 ?m (mean±SD) were specially made, and their dye content was optimized for use in crossed WLS-fibre arrays. The developed detector had a pixel size of 34 ?m×34 ?m, and exhibited spatial FWHM resolutions of 80±7 ?m and 61±6 ?m in the x and y directions, respectively. A small prototype detector demonstrated the capability of neutron imaging using Bragg edges of a Cu/Fe sample when using the pulsed-neutron source in the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex.

Nakamura, T.; Toh, K.; Kawasaki, T.; Honda, K.; Suzuki, H.; Ebine, M.; Birumachi, A.; Sakasai, K.; Soyama, K.; Katagiri, M.

2014-02-01

295

The scope of detector Medipix2 in micro-radiography of biological samples  

Microsoft Academic Search

We present our experimental setup devoted to high resolution X-ray micro-radiography that is suitable for imaging of small biological samples. The photon source is a FeinFocus micro-focus X-ray tube. The single photon counting pixel device Medipix2 serves as imaging area. Recently used imaging detectors as radiography films or scintillator detectors, cannot visualize required information about inner structure of scanned sample.

J. Dammer; F. Weyda; J. Jakubek; P. Skrabal; V. Sopko; D. Vavrik

2011-01-01

296

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

Microsoft Academic Search

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).

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

1996-01-01

297

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

PubMed

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. PMID:25430209

Bonura, M A; Ruiz, C L; Fehl, D L; Cooper, G W; Chandler, G; Hahn, K D; Nelson, A J; Styron, J D; Torres, J A

2014-11-01

298

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

SciTech Connect

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.

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

299

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

SciTech Connect

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.

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

300

Scintillator Strip ECAL Optimization  

E-print Network

The CALICE collaboration is developing a granular electromagnetic calorimeter using small scintillator strips for a future linear collider experiment. On developing of ~ 10^7 channel-ECAL in particle flow approach, CALICE is developing a technological prototype with 144 of 5 x 45 x (1 - 2) mm^3 strips on each 180 x 180 mm^2 base board unit in tandem with developing the design of scintillator strip and pixelated photon detector and their coupling after established the physics prototype which has required performance. A method of event reconstruction in such ECAL is also developed.

Katsushige Kotera

2014-04-07

301

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)

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.

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

2010-07-01

302

Experimental response functions and response matrices for 2.54-cm x 2.54 cm and 7.62 cm x 7.62 cm bismuth germanate scintillation detectors  

NASA Astrophysics Data System (ADS)

We report experimental response functions at twelve gamma-ray energies over the range of 123.6 keV to 11.67 MeV for a 2.54-cm-diameter x 2.54-cm-long and a 7.62-cm-diameter x 7.62-cm long bismuth germanate scintillation detector. The measurements were made at, or corrected to correspond to, source-to-detector distances of 100 cm. The resolutions of the detectors at a gamma-ray energy of 661.6 keV are 11.6 percent for the small detector and 13.0 percent for the large detector.

Kiziah, Rex R.; Lowell, John R.

1990-10-01

303

Experimental response functions spanning the gamma-ray energy range of 123.6 keV to 11.67 MeV and response matrix generation for bismuth germanate scintillation detectors  

NASA Astrophysics Data System (ADS)

We report experimental response functions at 12 gamma-ray energies over the range of 123.6 keV to 11.67 MeV for a 2.54 cm diameter × 2.54 cm long and a 7.62 cm diameter × 7.62 cm long bismuth germanate scintillation detector. The measurements were made at, or corrected to correspond to, source-to-detector distances of 100 cm. The resolutions of the detectors at a gamma-ray energy of 661.6 keV are 11.6% for the small detector and 13.0% for the large detector. We also present an interpolation method for generating a response function at any gamma-ray energy in the range of 123.6 keV to 11.67 MeV for either scintillator using the experimental response functions. Additionally, this method is used in constructing response matrices for unfolding gamma-ray pulse-height distributions acquired with the detectors. A computer code written in FORTRAN-77 generates the response matrices.

Kiziah, Rex R.; Lowell, John R.

1991-07-01

304

Thin YAP:Ce and LaBr3:Ce scintillators as proton detectors of a thin-film proton recoil neutron spectrometer for fusion and spallation sources applications  

NASA Astrophysics Data System (ADS)

Two thin inorganic scintillators based on YAP and LaBr3 crystals (1 in. diameter × 0.1 in. height) have been used for proton measurements at the Uppsala tandem accelerator in the energy range 4-8 MeV. Measurements show a comparable good energy resolution for the two detectors, better than 2% (FWHM) for 8 MeV protons, which compares to 3.8% (LaBr3) and 3.7% (YAP) obtained at the 1.3 MeV peak of a 60Co ?-ray source. The main advantages of these crystals are a fast scintillation time (less than 30 ns), an excellent light yield and the capability to operate in large neutron background, which make them ideal candidates as proton detectors of a thin-film proton recoil neutron spectrometer for application on fusion experiments and fast neutron spallation sources.

Cazzaniga, C.; Nocente, M.; Tardocchi, M.; Fazzi, A.; Hjalmarsson, A.; Rigamonti, D.; Ericsson, G.; Gorini, G.

2014-07-01

305

Glass and phosphor scintillators for x-ray imaging  

SciTech Connect

In x-ray imaging, many combinations of scintillators and detectors are used for a variety of reasons. This paper reviews several scintillators currently used in x-ray imaging systems in medical and non-destructive testing (NDT) applications.

Ellis, John [Collimated Holes, Inc., 460 Division Street, Campbell, California 95008 (United States)

1998-11-09

306

Separation and quantification of 238U, 232Th and rare earths in monazite samples by ion chromatography coupled with on-line flow scintillation detector.  

PubMed

An alternative procedure has been described for efficient separation and quantitative determination of uranium (U), thorium (Th) and rare earth elements (REEs) in monazite mineral by high performance ion chromatographic system (IC). Different variables affecting the distribution coefficient, the retention and hence separation efficiency such as eluent flow rate and concentrations of HCI and ammonium sulfate (NH4)2SO4 containing the mobile phase were studied. The developed separation protocol of U, Th and REEs was optimized using an Ion Pac CS5 separation column followed by post-column derivatization reaction with Arsenaso III and UV-VIS spectrophotometric detection. Comparative evaluation of U, Th and REEs concentration in monazite mineral was demonstrated using two different on-line detection modes including flow through cell scintillation detector (FSD) and UV-VIS spectrophotometer. Response of the FSD was found to be linear over the full range of activities investigated (4-100 Bq). The lower limits of detection (LLD) for the investigated radionuclides were 3.0+0.1 Bq for 238U and 6.0 +/- 0.1 Bq for 232Th. The detection of 238U and 232Th by FSD shows good agreement with the corresponding determination by UV-VIS spectrophotometer. The content of ThO2 and U3O8 in monazite sample were found to be 4.7 +/- 0.1% and 0.42 +/- 0.04% using UV-VIS detector and 4.3 +/- 0.1% and 0.45 +/- 0.1% using FSD, respectively. PMID:12361323

Borai, E H; Mady, A S

2002-10-01

307

Segmented crystalline scintillators: Empirical and theoretical investigation of a high quantum efficiency EPID based on an initial engineering prototype CsI(Tl) detector  

SciTech Connect

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 160x160 optically isolated, crystalline CsI(Tl) elements spaced at 1016 {mu}m pitch. The detector was coupled to an indirect detection-based active matrix array having a pixel pitch of 508 {mu}m, with each detector element registered to 2x2 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 ({approx}22%) compared to that of the conventional AMFPI ({approx}1%). The measured zero-frequency DQE was found to be lower than theoretical upper limits ({approx}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 ({approx}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.

Sawant, Amit; Antonuk, Larry E.; El-Mohri, Youcef; Zhao Qihua; Wang Yi; Li Yixin; Du Hong; Perna, Louis [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48103 (United States); Saint Gobain Crystals, Newbury, Ohio 44065 (United States)

2006-04-15

308

hybrid\\scriptsize{{MANTIS}}: a CPU-GPU Monte Carlo method for modeling indirect x-ray detectors with columnar scintillators  

NASA Astrophysics Data System (ADS)

The computational modeling of medical imaging systems often requires obtaining a large number of simulated images with low statistical uncertainty which translates into prohibitive computing times. We describe a novel hybrid approach for Monte Carlo simulations that maximizes utilization of CPUs and GPUs in modern workstations. We apply the method to the modeling of indirect x-ray detectors using a new and improved version of the code \\scriptsize{{MANTIS}}, an open source software tool used for the Monte Carlo simulations of indirect x-ray imagers. We first describe a GPU implementation of the physics and geometry models in fast\\scriptsize{{DETECT}}2 (the optical transport model) and a serial CPU version of the same code. We discuss its new features like on-the-fly column geometry and columnar crosstalk in relation to the \\scriptsize{{MANTIS}} code, and point out areas where our model provides more flexibility for the modeling of realistic columnar structures in large area detectors. Second, we modify \\scriptsize{{PENELOPE}} (the open source software package that handles the x-ray and electron transport in \\scriptsize{{MANTIS}}) to allow direct output of location and energy deposited during x-ray and electron interactions occurring within the scintillator. This information is then handled by optical transport routines in fast\\scriptsize{{DETECT}}2. A load balancer dynamically allocates optical transport showers to the GPU and CPU computing cores. Our hybrid\\scriptsize{{MANTIS}} approach achieves a significant speed-up factor of 627 when compared to \\scriptsize{{MANTIS}} and of 35 when compared to the same code running only in a CPU instead of a GPU. Using hybrid\\scriptsize{{MANTIS}}, we successfully hide hours of optical transport time by running it in parallel with the x-ray and electron transport, thus shifting the computational bottleneck from optical to x-ray transport. The new code requires much less memory than \\scriptsize{{MANTIS}} and, as a result, allows us to efficiently simulate large area detectors.

Sharma, Diksha; Badal, Andreu; Badano, Aldo

2012-04-01

309

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

PubMed Central

Purpose: The goal of the present work was to evaluate the accuracy of a plastic scintillation detector (PSD) system to perform in-phantom dosimetry during 192Ir high dose rate (HDR) brachytherapy treatments. Methods: A PSD system capable of stem effect removal was built. A red–green–blue photodiode connected to a dual-channel electrometer was used to detect the scintillation light emitted from a green scintillation component and transmitted along a plastic optical fiber. A clinically relevant prostate treatment plan was built using the HDR brachytherapy treatment planning system. An in-house fabricated template was used for accurate positioning of the catheters, and treatment delivery was performed in a water phantom. Eleven catheters were inserted and used for dose delivery from 192Ir radioactive source, while two others were used to mimic dosimetry at the rectum wall and in the urethra using a PSD. The measured dose and dose rate data were compared to the expected values from the planning system. The importance of removing stem effects from in vivo dosimetry using a PSD during 192Ir HDR brachytherapy treatments was assessed. Applications for dwell position error detection and temporal verification of the treatment delivery were also investigated. Results: In-phantom dosimetry measurements of the treatment plan led to a ratio to the expected dose of 1.003?±?0.004 with the PSD at different positions in the urethra and 1.043?±?0.003 with the PSD inserted in the rectum. Verification for the urethra of dose delivered within each catheter and at specific dwell positions led to average measured to expected ratios of 1.015?±?0.019 and 1.014?±?0.020, respectively. These values at the rectum wall were 1.059?±?0.045 within each catheter and 1.025?±?0.028 for specific dwell positions. The ability to detect positioning errors of the source depended of the tolerance on the difference to the expected value. A 5-mm displacement of the source was detected by the PSD system from 78% to 100% of the time depending on the acceptable range value. The implementation of a stem effect removal technique was shown to be necessary, particularly when calculating doses at specific dwell positions, and allowed decreasing the number of false-error detections—the detection of an error when it should not be the case—from 19 to 1 for a 5% threshold out of 43 measurements. The use of the PSD system to perform temporal verification of elapsed time by the source in each catheter—generally on the order of minutes—was shown to be in agreement within a couple of seconds with the treatment plan. Conclusions: We showed that the PSD system used in this study, which was capable of stem effect removal, can perform accurate dosimetry during 192Ir HDR brachytherapy treatment in a water phantom. The system presented here shows some clear advantages over previously proposed dosimetry systems for HDR brachytherapy, and it has the potential for various online verifications of treatment delivery quality. PMID:21776789

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

2011-01-01

310

LORA: A scintillator array for LOFAR to measure extensive air showers  

NASA Astrophysics Data System (ADS)

The measurement of the radio emission from extensive air showers, induced by high-energy cosmic rays, is one of the key science projects of the LOFAR radio telescope. The LOfar Radboud air shower Array (LORA) has been installed in the core of LOFAR in the Netherlands. The main purpose of LORA is to measure the properties of air showers and to trigger the read-out of the LOFAR radio antennas to register extensive air showers. The experimental set-up of the array of scintillation detectors and its performance are described.

Thoudam, S.; Buitink, S.; Corstanje, A.; Enriquez, J. E.; Falcke, H.; Frieswijk, W.; Hörandel, J. R.; Horneffer, A.; Krause, M.; Nelles, A.; Schellart, P.; Scholten, O.; ter Veen, S.; van den Akker, M.

2014-12-01

311

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

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.

Khanbekov, N. D., E-mail: xanbekov@gmail.com [Institute of Theoretical and Experimental Physics (Russian Federation)

2013-09-15

312

Use of Silicon Photomultipliers in ZnS:6LiF scintillation neutron detectors: signal extraction in presence of high dark count rates  

NASA Astrophysics Data System (ADS)

We report on the possibility of using Silicon Photomultipliers (SiPMs) to detect the scintillation light from neutron conversion in ZnS:6LiF scintillators. The light is collected by wavelength-shifting fibers embedded into the scintillator. The difficulty of extracting neutron signals in the presence of high dark count rates of the SiPMs is addressed by applying a dedicated processing algorithm to analyze the temporal distribution of the SiPM pulses. With a single-channel prototype detection unit we demonstrate a very good neutron signal extraction at SiPM dark count rates of about 1 MHz.

Stoykov, A.; Mosset, J.-B.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

2014-06-01

313

Ytterbium-based compounds as fast and dense inorganic scintillators  

Microsoft Academic Search

The recent observation of UV scintillation in mixed yttrium\\/ytterbium aluminium garnets opened the field of investigation to a new class of scintillating crystals. Their interesting luminescence properties make them very attractive not only for solar neutrino spectroscopy as ytterbium containing detector material, but also for radiation detection in general, as dense, fast and efficient scintillators. Studies of charge transfer luminescence

Rémi Chipaux; Michel Cribier; Christophe Dujardin; Nicolas Garnier; Natacha Guerassimova; Jacques Mallet; Jean-Pierre Meyer; Christian Pédrini; Ashot G. Petrosyan

2001-01-01

314

A high resolution scintillating fiber gamma-ray telescope  

Microsoft Academic Search

Scintillating fibers coupled to position sensitive photomultipliers have good angular precision and good energy resolution in detecting gamma-rays. Scintillating fibers stacked up into scintillating fiber planes U, V and W that are rotated by 60° angle relative to each other and coupled to position sensitive photomultipliers can be used as high resolution imaging gamma-ray detectors. With this arrangement the Compton

M. Atac; D. B. Cline; E. J. Fenyves; R. C. Chaney; H. Hammack

1989-01-01

315

Measurements of the Time Structure of Hadronic Showers in a Scintillator-Tungsten HCAL  

E-print Network

For calorimeter applications requiring precise time stamping, the time structure of hadronic showers in the detector is a crucial issue. This applies in particular to detector concepts for CLIC, where a hadronic calorimeter with tungsten absorbers is being considered to achieve a high level of shower containment while satisfying strict space constraints. The high hadronic background from gamma gamma to hadrons processes at 3 TeV in combination with the 2 GHz bunch crossing frequency at CLIC requires good time stamping in the detectors. To provide first measurements of the time structure in a highly granular scintillator-tungsten calorimeter, T3B, a dedicated timing experiment, was installed behind the last layer of the CALICE WHCAL prototype, a 30 layer tungsten scintillator calorimeter. T3B consists of 15 small scintillator cells with embedded silicon photomultipliers, read out with fast digitizers over a time window of 2.4 us, and provides detailed measurements of the time structure of the signal. The offline data reconstruction performs an automatic gain calibration using noise events recorded between physics triggers and allows the determination of the arrival time of each photon at the photon sensor. The T3B setup, its calibration and data reconstruction, as well as first results of the time structure of the calorimeter response for 10 GeV pions recorded at the CERN PS confronted with Geant4 simulations using different physics lists are discussed.

Frank Simon; for the CALICE Collaboration

2011-09-14

316

Scintillating Stars  

NSDL National Science Digital Library

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?

Riddle, Bob

2003-02-01

317

Detectors  

DOEpatents

The apparatus and method provide techniques through which both alpha and beta emission determinations can be made simultaneously using a simple detector structure. The technique uses a beta detector covered in an electrically conducting material, the electrically conducting material discharging ions generated by alpha emissions, and as a consequence providing a measure of those alpha emissions. The technique also offers improved mountings for alpha detectors and other forms of detectors against vibration and the consequential effects vibration has on measurement accuracy.

Orr, Christopher Henry (Calderbridge, GB); Luff, Craig Janson (Calderbridge, GB); Dockray, Thomas (Calderbridge, GB); Macarthur, Duncan Whittemore (Los Alamos, NM); Bounds, John Alan (Los Alamos, NM); Allander, Krag (Los Alamos, NM)

2002-01-01

318

Avalanche Photodiode for liquid xenon scintillation: quantum efficiency and gain  

Microsoft Academic Search

We report on measurements with a large area, silicon Avalanche Photodiode (APD) as photodetector for the ultraviolet scintillation light of liquid xenon (LXe) at temperatures between 167 and 188 K. The maximum gain of the APD for the scintillation light from a 210Po alpha-source in LXe was 5.3 × 103. Based on the geometry of the setup, the quantum efficiency

P. Shagin; R. Gomez; U. Oberlack; P. Cushman; B. Sherwood; M. McClish; R. Farrell

2009-01-01

319

Microprocessor-based single particle calibration of scintillation counter  

NASA Astrophysics Data System (ADS)

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

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

1985-08-01

320

Detection of liquid xenon scintillation light with a Silicon Photomultiplier  

E-print Network

We have studied the feasibility of a silicon photomultiplier (SiPM) to detect liquid xenon (LXe) scintillation light. The SiPM was operated inside a small volume of pure LXe, at -95 degree Celsius, irradiated with an internal Am-241 alpha source. The gain of the SiPM at this temperature was estimated to be 1.8 x 10^6 with bias voltage at 52 V. Based on the geometry of the setup, the quantum efficiency of the SiPM was estimated to be 22% at the Xe wavelength of 178 nm. The low excess noise factor, high single photoelectron detection efficiency, and low bias voltage of SiPMs make them attractive alternative UV photon detection devices to photomultiplier tubes (PMTs) for liquid xenon detectors, especially for experiments requiring a very low energy detection threshold, such as neutralino dark matter searches.

Aprile, E; Ni, K; Shagin, P

2006-01-01

321

Detection of liquid xenon scintillation light with a silicon photomultiplier  

NASA Astrophysics Data System (ADS)

We have studied the feasibility of a silicon photomultiplier (SiPM) to detect liquid xenon (LXe) scintillation light. The SiPM was operated inside a small volume of pure liquid xenon (LXe), at -95C, irradiated with an internal 241Am ? source. The gain of the SiPM at this temperature was estimated to be 1.8×10 at a 52 V bias voltage. Based on the geometry of the setup, the quantum efficiency of the SiPM was estimated to be 22% (5.5% is the photon detection efficiency) at the Xe wavelength of 178 nm. The low excess noise factor (about 1.05), high single photoelectron detection efficiency, and low bias voltage of SiPMs make them attractive alternative UV photon detection devices to photomultiplier tubes (PMTs) for liquid xenon detectors, especially for experiments requiring a very low energy detection threshold, such as neutralino dark matter searches.

Aprile, E.; Cushman, P.; Ni, K.; Shagin, P.

2006-01-01

322

Detection of liquid xenon scintillation light with a Silicon Photomultiplier  

E-print Network

We have studied the feasibility of a silicon photomultiplier (SiPM) to detect liquid xenon (LXe) scintillation light. The SiPM was operated inside a small volume of pure LXe, at -95 degree Celsius, irradiated with an internal Am-241 alpha source. The gain of the SiPM at this temperature was estimated to be 1.8 x 10^6 with bias voltage at 52 V. Based on the geometry of the setup, the quantum efficiency of the SiPM was estimated to be 22% at the Xe wavelength of 178 nm. The low excess noise factor, high single photoelectron detection efficiency, and low bias voltage of SiPMs make them attractive alternative UV photon detection devices to photomultiplier tubes (PMTs) for liquid xenon detectors, especially for experiments requiring a very low energy detection threshold, such as neutralino dark matter searches.

E. Aprile; P. Cushman; K. Ni; P. Shagin

2005-01-03

323

A helical scintillating fiber hodoscope  

NASA Astrophysics Data System (ADS)

A novel scintillating fiber hodoscope in helically cylindric geometry has been developed for detection of low multiplicity events of fast protons and other light charged particles in the internal target experiment EDDA at the Cooler Synchrotron COSY. The hodoscope consists of 640 scintillating fibers (2.5 mm diameter), arranged in four layers surrounding the COSY beam pipe. The fibers are helically wound in opposing directions and read out individually using 16-channel photomultipliers connected to a modified commercial encoding system. The detector covers an angular range of 9°? ??72° and 0°? ??360° in the lab frame. The detector length is 590 mm, the inner diameter 161 mm. Geometry and granularity of the hodoscope afford a position resolution of about 1.3 mm. The detector design took into consideration a maximum of reliability and a minimum of maintenance. An LED array may be used for monitoring purposes.

Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Bissel, T.; Bollmann, R.; Busch, M.; Büßer, K.; Colberg, T.; Demirörs, L.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Eversheim, P. D.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Groß, A.; Groß-Hardt, R.; Hinterberger, F.; Jahn, R.; Jeske, M.; Jonas, E.; Krause, H.; Lahr, U.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuck, T.; Meinerzhagen, A.; Nähle, O.; Pfuff, M.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Sanz, B.; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Thomas, S.; Trelle, H. J.; Weise, E.; Wellinghausen, A.; Wiedmann, W.; Woller, K.; Ziegler, R.; EDDA Collaboration

1999-07-01

324

Magnetic fields and SDC endcap scintillator performance  

SciTech Connect

Many detectors designed to operate in colliders contain both magnetic fields, usually solenoids, and scintillators. The former is known to influence the operation of the latter. A first look is taken in this note at the implications of that influence for the SDC detector.

Green, D.

1993-01-01

325

Testing and Installation of a High Efficiency CsI Scintillator Array  

NASA Astrophysics Data System (ADS)

Experiments on neutron-rich nuclei have identified changes to the structure of nuclei far from stability. The Sweeper-MoNA- LISA facility at the National Superconducting Cyclotron Laboratory (NSCL), located at Michigan State University, is used for performing experiments on neutron-rich nuclei. Currently, these experiments are limited to the mass region below neon due to the resolution of the charged fragment detectors, which limit the isotope separation. The resolution of the system will be improved with changes to the setup, primarily due to a new scintillator array. The new array will consist of twenty-five sodium-doped CsI crystals arranged in a 5 x 5 configuration. The array will be used to measure the kinetic energy of charged fragments with energies in the GeV range. The improved resolution will allow experiments of unbound systems above neon. The testing and assembly of the detector array will be presented.

Viscariello, Natalie; Casarotto, Stuart; Frank, Nathan; Smith, Jenna; Thoennessen, Michael

2011-10-01

326

Preshower detector for ? +? - hadronic atom studies  

NASA Astrophysics Data System (ADS)

A preshower (PSh) detector has been prepared, tested and used at the CERN-DIRAC experiment [B. Adeva, et al., DIRAC proposal, CERN/SPSLC 95-1, SPSLC/P 284, 1995]. The aim of this experiment was to test some nonperturbative QCD predictions [J. Gasser, H. Leutwyler, Phys. Lett. B 125 (1983) 325; J. Gasser, H. Leutwyler, Ann. Phys. 158 (1984) 142; J. Gasser, H. Leutwyler, Nucl. Phys. B 250 (1985) 465; J. Bijnens, G. Colangelo, G. Ecker, J. Gasser, M.E. Sainio, Phys. Lett. B 374 (1996) 210] by measuring pionium (? +? - hadronic atom) lifetime. In this context the PSh detector, together with the Cherenkov detector, pursued to reject the background electron pairs in the region 1-4 GeV where the pion pairs from atom breakup were present. The technique used for pion/electron separation was to probe the electron shower development in the early formation stage in Pb converter. We have studied the dependence of the amplitude spectra on particle momentum and converter and scintillator thickness. The estimated electron rejection efficiency was better than 85% with a pion loss less than 5% for a preshower detector with Pb converter thickness w Pb=2.5 cm and scintillator slab w Sc=1 cm. The PSh track efficiency within the DIRAC setup has been measured with a global efficiency per arm better than 99%, slab efficiency per arm better than 96% and corresponding pair events efficiency per arm ˜99% and per slab ˜93%.

Pentia, M.; Ciocarlan, C.; Constantinescu, S.; Gugiu, M.; Caragheorgheopol, Gh.

2009-05-01

327

Optimization of light collection from crystal scintillators for cryogenic experiments  

E-print Network

High light collection efficiency is an important requirement in any application of scintillation detectors. The purpose of this study is to investigate the possibility for improving this parameter in cryogenic scintillation bolometers, which can be considered as a promising detectors in experiments investigating neutrinoless double beta decay and dark matter. Energy resolutions and relative pulse amplitudes of scintillation detectors using ZnWO4 scintillation crystals of different shapes (cylinder 20 mm in dimater by 20 mm and hexagonal prism with diagonal 20 mm and height 20 mm), reflector materials and shapes, optical contact and surface properties (polished and diffused) were measured at room temperature. Propagation of optical photons in these experimental conditions was simulated using Geant4 and ZEMAX codes. The results of the simulations are found to be in good agreement with each other and with direct measurements of the crystals. This could be applied to optimize the geometry of scintillation detectors used in the cryogenic experiments.

F. A. Danevich; R. V. Kobychev; V. V. Kobychev; H. Kraus; V. B. Mikhailik; V. M. Mokina

2014-02-10

328

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.

2011-11-01

329

FNAL-NICADD extruded scintillator  

SciTech Connect

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

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

2005-09-01

330

SNO+ Scintillator Purification and Assay  

SciTech Connect

We describe the R and D on the scintillator purification and assay methods and technology for the SNO+ neutrino and double-beta decay experiment. The SNO+ experiment is a replacement of the SNO heavy water with liquid scintillator comprised of 2 g/L PPO in linear alkylbenzene (LAB). During filling the LAB will be transported underground by rail car and purified by multi-stage distillation and steam stripping at a flow rate of 19 LPM. While the detector is operational the scintillator can be recirculated at 150 LPM (full detector volume in 4 days) to provide repurification as necessary by either water extraction (for Ra, K, Bi) or by functional metal scavenger columns (for Pb, Ra, Bi, Ac, Th) followed by steam stripping to remove noble gases and oxygen (Rn, O{sub 2}, Kr, Ar). The metal scavenger columns also provide a method for scintillator assay for ex-situ measurement of the U and Th chain radioactivity. We have developed ''natural'' radioactive spikes of Pb and Ra in LAB and use these for purification testing. Lastly, we present the planned operating modes and purification strategies and the plant specifications and design.

Ford, R.; Vazquez-Jauregui, E. [SNOLAB, Creighton Mine, Lively, P3Y 1N2 (Canada); Chen, M. [Department of Physics, Queen's University, Kingston, K7L 3N6 (Canada); Chkvorets, O.; Hallman, D. [Department of Physics, Laurentian University, Sudbury, P3E 2C6 (Canada)

2011-04-27

331

New Organic Scintillators for Neutron Detection  

NASA Astrophysics Data System (ADS)

This paper present the current work on neutron detection in Soltan Institute for Nuclear Studies. Lately, we have focused our research on the development of new organic scintillators including liquid scintillators for neutron detection and associated measurements. We measured liquid scintillators (also 10B—doped for thermal neutron detection) 3He tubes, composites, etc. Response of the following detectors on thermal neutrons, fast neutrons and gamma radiation—the pulse shape discrimination (PSD)—has been mainly performed by means of a zero—crossing (ZC) method.

Iwanowska, Joanna; Szczee?niak, Tomasz

2010-01-01

332

A miniature x-ray fluorescence setup  

NASA Astrophysics Data System (ADS)

A miniature low-power x-ray fluorescence (XRF) setup has been designed, realized, and tested in vacuum. The experimental setup is centimeter sized and consists of an x-ray source and an electrically cooled silicon detector. The x-ray source has diamond membrane electrodes; the cathode is a field emitting microstructure and the anode is a metal film deposited on a diamond membrane. Anode radiation emergent through one of the diamond membrane electrodes induces characteristic x-ray radiation from a sample. By miniaturization of an XRF setup extremely low power consumption with acceptable yield and signal level is possible because of the small distances involved between source and sample and between sample and detector. The lightweighted XRF setup is intended for in situ materials analysis, e.g., for spacecraft applications, or probe mounted for portable mineralogy, archaeometry, or forensic equipment. In this article an initial test of the fluorescence setup is described and qualitative experimental results are presented and analyzed.

Ribbing, Carolina; Andersson, Marit; Hjort, Klas; Lundqvist, Hans

2003-07-01

333

Ceramic-like scintillators  

Microsoft Academic Search

Scintillator bodies comprising fluorescent materials and having high optical translucency with low light absorption and methods of making the scintillator bodies are disclosed. In accordance with one embodiment of the invention, the scintillator bodies are formed by a hot-pressing process. In another embodiment, coldpressing followed by sintering is employed. Another embodiment employs controlled cooling. Another embodiment employs hotforging. The scintillator

D. A. Cusano; F. F. Holub; S. Prochazka

1980-01-01

334

LabVIEW Data Acquisition for NE213 Neutron Detector  

SciTech Connect

A neutron spectroscopy system based on a NE213 liquid scintillation detector at the Stanford Linear Accelerator Center measures neutron energies from a few MeV up to 800 MeV. The neutrons are produced from the electron beam and target interactions. The NE 213 scintillator, coupled with a Photomultiplier Tube (PMT), detects and converts radiation into electric pulses for signal processing. Signals are processed through Nuclear Instrument Modules (NIM) and Computer Automated Measurement and Control (CAMAC) modules. The processed pulses are then fed into a CAMAC analog to digital converter module (ADC). The ADC classifies the incoming analog pulses into one of 2048 digital channels. Data acquisition (DAQ) software based on LabVIEW version 7.0 acquires and organizes data from the CAMAC ADC. The DAQ system presents a spectrum showing a relationship between pulse events and respective charge (digital channel number). Various photon sources, such as Co-60, Y-88, and AmBe-241, are used to calibrate the NE213 detector. For each source, a Compton edge and reference energy in MeVee is obtained, resulting in a calibration curve. This project is focused on the development of a DAQ system and control setup to collect and process information from a NE213 liquid scintillation detector. A manual is also created to document the process of the development and interpretation of the LabVIEW-based DAQ system.

Gangadharan, Dhevan

2003-09-23

335

Real-time volumetric scintillation dosimetry  

NASA Astrophysics Data System (ADS)

The goal of this brief review is to review the current status of real-time 3D scintillation dosimetry and what has been done so far in this area. The basic concept is to use a large volume of a scintillator material (liquid or solid) to measure or image the dose distributions from external radiation therapy (RT) beams in three dimensions. In this configuration, the scintillator material fulfills the dual role of being the detector and the phantom material in which the measurements are being performed. In this case, dose perturbations caused by the introduction of a detector within a phantom will not be at issue. All the detector configurations that have been conceived to date used a Charge-Coupled Device (CCD) camera to measure the light produced within the scintillator. In order to accurately measure the scintillation light, one must correct for various optical artefacts that arise as the light propagates from the scintillating centers through the optical chain to the CCD chip. Quenching, defined in its simplest form as a nonlinear response to high-linear energy transfer (LET) charged particles, is one of the disadvantages when such systems are used to measure the absorbed dose from high-LET particles such protons. However, correction methods that restore the linear dose response through the whole proton range have been proven to be effective for both liquid and plastic scintillators. Volumetric scintillation dosimetry has the potential to provide fast, high-resolution and accurate 3D imaging of RT dose distributions. Further research is warranted to optimize the necessary image reconstruction methods and optical corrections needed to achieve its full potential.

Beddar, S.

2015-01-01

336

Position and energy resolution of the Photo-Ionization Proportional Scintillation (PIPS) chamber  

NASA Astrophysics Data System (ADS)

Data are presented for energy and position resolutions, for a PIPS chamber, that couples a gas proportional scintillation counter with a photoionization detector. Possible improvements are considered.

Alegria Feio, M.; Policarpio, A. J. P. L.

337

Analysis of Resistive Plate Counter Detector used at Hadron Colliders  

NASA Astrophysics Data System (ADS)

Resistive Plate Counters (RPC) used for muon detection in the ATLAS and CMS experiments at the Large Hadron Collider are essentially based on the same design as those currently being installed for the level one muon trigger upgrade of the PHENIX experiment at the Relativistic Heavy Ion Collider. A full size RPC prototype double gas gap RPC was constructed for detector performance studies in the PHENIX RPC assembly laboratory at BNL. The RPC was then taken to UIUC where a setup of scintillators and drift chambers makes it possible to reconstruct cosmic ray tracks with a position resolution of about 1 mm. This tracking makes it possible to characterize RPC efficiencies and position resolution as a function of position in the detector and to study the efficiency near the detector edges and in regions where mechanical spacers in the gas gaps are located.

Burnap, Alex

2009-10-01

338

InI nuclear radiation detectors  

Microsoft Academic Search

Semiconductor radiation detectors were fabricated on single crystal wafers on indium iodide and tested both as direct radiation detectors and as optical detectors coupled to a scintillator crystal. Indium iodide is shown to be a promising material for fabricating room-temperature photodetectors for use in scintillation spectroscopy due to its high resistivity, good charge transport properties, and high quantum efficiency in

M. R. Squillante; C. Zhou; J. Zhang; L. P. Moy; K. S. Shah

1992-01-01

339

Buried plastic scintillator muon telescope  

NASA Astrophysics Data System (ADS)

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.

Sanchez, F.; Medina-Tanco, G. A.; D'Olivo, J. C.; et al.

340

Detection of high frequency intensity oscillations at RESEDA using the CASCADE detector  

NASA Astrophysics Data System (ADS)

We have explored the technological potential of combining neutron resonance spin echo (NRSE) with the time-of-flight method in quasielastic neutron scattering (QENS) experiments. For these test measurements at the new NRSE instrument RESEDA (FRM II, Munich), we have employed CASCADE, one of the fastest neutron detectors in the world, developed at the University of Heidelberg. Conventionally, scintillation detectors are used, in order to detect neutron intensities with high time resolution. In contrast, we used the new CASCADE detector converting neutrons in thin 10B layers being capable of resolving neutron intensity modulations up to the megahertz regime. This fast detector allows us to abandon the last resonance flip coil of a standard NRSE setup. The classical spin echo signal is replaced by a time-modulated signal. In this setup, fast intensity modulations are present at the detector position. In order to demonstrate, that NRSE-CASCADE operates well up to detector frequencies of 10 MHz, we performed elastic polarization test measurements on a standard sample. The CASCADE detector is a multidetector accumulating counts in 128 × 128 pixels on a surface of 200 mm × 200 mm. We have analyzed the signal in 600 pixels, providing information about the spin phase reaching the detector and about the resolution function of this new variant tested at RESEDA.

Häussler, W.; Böni, P.; Klein, M.; Schmidt, C. J.; Schmidt, U.; Groitl, F.; Kindervater, J.

2011-04-01

341

CARMA Correlator Graphical Setup  

NASA Astrophysics Data System (ADS)

CARMA Correlator Graphical Setup (CGS) is a Java tool to help users of the Combined Array for Research in Millimeter-wave Astronomy (CARMA) plan observations. It allows users to visualize the correlator bands overlaid on frequency space and view spectral lines within each band. Bands can be click-dragged to anywhere in frequency and can have their properties (e.g., bandwidth, quantization level, rest frequency) changed interactively. Spectral lines can be filtered from the view by expected line strength to reduce visual clutter. Once the user is happy with the setup, a button click generates the Python commands needed to configure the correlator within the observing script. CGS can also read Python configurations from an observing script and reproduce the correlator setup that was used. Because the correlator hardware description is defined in an XML file, the tool can be rapidly reconfigured for changing hardware. This has been quite useful as CARMA has recently commissioned a new correlator. The tool was written in Java by high school summer interns working in UMD's Laboratory for Millimeter Astronomy and has become an essential planning tool for CARMA PIs.

Wu, D.; Shaya, B.; Pound, M. W.

2011-07-01

342

Scintillators and applications thereof  

DOEpatents

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.

Williams, Richard T.

2014-07-15

343

Liquid-helium scintillation detection with germanium photodiodes  

SciTech Connect

Special high-purity germanium photodiodes have been developed for the direct detection of vacuum ultraviolet scintillations in liquid helium. The photodiodes are immersed in the liquid helium, and scintillations are detected through one of the bare sides of the photodiodes. Test results with scintillation photons produced by 5.3-MeV ..cap alpha.. particles are presented. The use of these photodiodes as liquid-helium scintillation detectors may offer substantial improvements over the alternate detection method requiring the use of wavelength shifters and photomultiplier tubes.

Luke, P.N.; Haller, E.E.; Steiner, H.M.

1982-05-01

344

Scintillator materials for calorimetry  

SciTech Connect

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.

Weber, M.J. [Lawrence Berkeley Lab., CA (United States). Life Sciences Div.

1994-09-01

345

Scintillating LXe\\/LKr electromagnetic calorimeter  

Microsoft Academic Search

A scintillating LXe\\/LKr electromagnetic calorimeter has been built at the ITEP and tested at the BATES (MIT) accelerator. The detector consists of PMT matrix and 45 light collecting cells made of aluminized 50 microns Mylar partially covered with p-terphenyle as a wavelength-shifter (WLS). Each pyramidal cell has (2.1×2.1)×40×(4.15×4.15) cm dimensions and is viewed by FEU-85 glass-window photomultiplier. The detector has

D. Yu. Akimov; A. I. Bolozdynya; D. L. Churakov; V. N. Afonasyev; S. G. Belogurov; A. D. Brastilov; A. A. Burenkov; L. N. Gusev; V. F. Kuzichev; V. N. Lebedenko; T. A. Osipova; I. A. Rogovsky; G. A. Safronov; S. A. Simonychev; V. N. Solovov; V. S. Sopov; G. N. Smirnov; V. P. Tchernyshev; M. Chen; M. M. Smolin; W. Turchinetz; R. A. Minakova; V. M. Shershukov; V. H. Dodohov

1994-01-01

346

Scintillating LXe\\/LKr electromagnetic calorimeter  

Microsoft Academic Search

A scintillating LXe\\/LKr electromagnetic calorimeter has been built at the ITEP and tested at the BATES (MIT) accelerator. The detector consists of a PMT matrix and 45 light collecting cells made of aluminized Mylar partially covered with p-terphenyl as a wavelength-shifter (WLS). Each pyramidal cell has (2.1×2.1)×40×(4.15×4.15) cm dimensions and is viewed by an FEU-85 glass-window photomultiplier. The detector has

D. Yu. Akimov; A. J. Bolozdynya; D. L. Churakov; V. N. Afonasyev; S. G. Belogurov; A. D. Brastilov; A. A. Burenkov; L. N. Gusev; V. F. Kuzichev; V. N. Lebedenko; T. A. Osipova; I. A. Rogovsky; A. Safronov; A. Simonychev; V. N. Solovov; V. S. Sopov; G. N. Smirnov; V. P. Tchernyshev; M. Chen; M. M. Smolin; W. Turchinetz; R. A. Minakova; V. M. Shershukov; V. H. Dodohov

1995-01-01

347

The Oriented Scintillation Spectrometer Experiment - Instrument description  

Microsoft Academic Search

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)

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

348

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

349

Measurements of proportional scintillation in liquid xenon using thin wires  

E-print Network

Proportional scintillation in liquid xenon has a promising application in the field of direct dark matter detection, potentially allowing for simpler, more sensitive detectors. However, knowledge of the basic properties of the phenomenon as well as guidelines for its practical use are currently limited. We report here on measurements of proportional scintillation light emitted in liquid xenon around thin wires. The maximum proportional scintillation gain of $287^{+97}_{-75}$ photons per drift electron was obtained using 10 $\\mu$m diameter gold plated tungsten wire. The thresholds for electron multiplication and proportional scintillation are measured as $725^{+48}_{-139}$ and $412^{+10}_{-133}$ kV/cm, respectively. The threshold for proportional scintillation is in good agreement with a previously published result, while the electron multiplication threshold represents a novel measurement. A complete set of parameters for the practical use of the electron multiplication and proportional scintillation processe...

Aprile, E; Goetzke, L W; Fernandez, A J Melgarejo; Messina, M; Naganoma, J; Plante, G; Rizzo, A; Shagin, P; Wall, R

2014-01-01

350

Improved event positioning in a gamma ray detector using an iterative position-weighted centre-of-gravity algorithm.  

PubMed

An iterative position-weighted centre-of-gravity algorithm was developed and tested for positioning events in a silicon photomultiplier (SiPM)-based scintillation detector for positron emission tomography. The algorithm used a Gaussian-based weighting function centred at the current estimate of the event location. The algorithm was applied to the signals from a 4 × 4 array of SiPM detectors that used individual channel readout and a LYSO:Ce scintillator array. Three scintillator array configurations were tested: single layer with 3.17 mm crystal pitch, matched to the SiPM size; single layer with 1.5 mm crystal pitch; and dual layer with 1.67 mm crystal pitch and a ½ crystal offset in the X and Y directions between the two layers. The flood histograms generated by this algorithm were shown to be superior to those generated by the standard centre of gravity. The width of the Gaussian weighting function of the algorithm was optimized for different scintillator array setups. The optimal width of the Gaussian curve was found to depend on the amount of light spread. The algorithm required less than 20 iterations to calculate the position of an event. The rapid convergence of this algorithm will readily allow for implementation on a front-end detector processing field programmable gate array for use in improved real-time event positioning and identification. PMID:23798644

Liu, Chen-Yi; Goertzen, Andrew L

2013-07-21

351

Investigation of LaBr3:Ce scintillator with excellent property  

NASA Astrophysics Data System (ADS)

In order to satisfy high precision requirement for the modern nuclear physics experiment detectors and radiologic imaging technology equipments, we do some researches in improving the resolution of the detector with LaBr3:Ce scintillator.

Chen, Jin-da; Hu, Zheng-guo; Zhang, Xiu-ling; Chen, Ze; Yuan, Xiao-hua; Sun, Zhi-yu; Guo, Zhong-yan; Xu, Hu-shan

2014-04-01

352

Scintillator reflective layer coextrusion  

DOEpatents

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.

Yun, Jae-Chul (Naperville, IL); Para, Adam (St. Charles, IL)

2001-01-01

353

Neutrino Detectors: Challenges and Opportunities  

SciTech Connect

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.

Soler, F. J. P. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2011-10-06

354

Compact gamma detectors based on FBK SiPMs for a Ps Time Of Flight apparatus  

NASA Astrophysics Data System (ADS)

Silicon Photomultipliers (SiPMs) are single-photon detectors currently used in many applications as a valid alternative to Photomultiplier Tubes (PMTs). In fact, SiPMs present several advantages compared to PMTs, in terms of size, ruggedness, insensitivity to magnetic fields and voltage supply. In this work, we evaluated the use of SiPMs produced by FBK (Fondazione Bruno Kessler)-AdvanSid (Trento, Italy) in Positronium Time Of Flight (Ps TOF) technique. The aim of this technique is the study of the energy of Ps emitted by porous media for advanced experiments in the field of antimatter physics and, in the future, for open porosities characterization. The TOF spectrometer in operation at the positron beam of the University of Trento (Italy) is based on five gamma detectors composed of NaI(Tl) scintillators coupled to PMTs. We compared the performance of one of these standard detectors against a detector formed by two 4 × 4 mm2 SiPMs coupled to a 4 × 4 × 30 mm3 LYSO (Cerium-doped Lutetium Yttrium Orthosilicate) scintillator. The LYSO+SiPM detector was characterized for timing and energy resolution as well as for the background emission level. It is shown that SiPMs, thanks to their small size and versatility, can be coupled successfully to small scintillators, obtaining more compact detectors with respect to the NaI(Tl)+PMT detectors. The design of an array of detectors with wide angular acceptance and spatial resolution is discussed in order to improve the performances of Ps-TOF setups.

Mazzuca, E.; Benetti, M.; Mariazzi, S.; Sennen Brusa, R.; Dalla Betta, G.-F.; Piemonte, C.

2012-05-01

355

The COMPASS Setup for Physics with Hadron Beams  

E-print Network

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.

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

356

Novel method for hit-position reconstruction using voltage signals in plastic scintillators and its application to Positron Emission Tomography  

E-print Network

Currently inorganic scintillator detectors are used in all commercial Time of Flight Positron Emission Tomograph (TOF-PET) devices. The J-PET collaboration investigates a possibility of construction of a PET scanner from plastic scintillators which would allow for single bed imaging of the whole human body. This paper describes a novel method of hit-position reconstruction based on sampled signals and an example of an application of the method for a single module with a 30 cm long plastic strip, read out on both ends by Hamamatsu R4998 photomultipliers. The sampling scheme to generate a vector with samples of a PET event waveform with respect to four user-defined amplitudes is introduced. The experimental setup provides irradiation of a chosen position in the plastic scintillator strip with an annihilation gamma quanta of energy 511~keV. The statistical test for a multivariate normal (MVN) distribution of measured vectors at a given position is developed, and it is shown that signals sampled at four thresholds in a voltage domain are approximately normally distributed variables. With the presented method of a vector analysis made out of waveform samples acquired with four thresholds, we obtain a spatial resolution of about 1 cm and a timing resolution of about 80 ps

L. Raczynski; P. Moskal; P. Kowalski; W. Wislicki; T. Bednarski; P. Bialas; E. Czerwinski; L . Kaplon; A. Kochanowski; G. Korcyl; J. Kowal; T. Kozik; W. Krzemien; E. Kubicz; M. Molenda; I. Moskal; Sz. Niedzwiecki; M. Palka; M. Pawlik-Niedzwiecka; Z. Rudy; P. Salabura; N. G. Sharma; M. Silarski; A. Slomski; J. Smyrski; A. Strzelecki; A. Wieczorek; M. Zielinski; N. Zon

2014-07-31

357

Novel method for hit-position reconstruction using voltage signals in plastic scintillators and its application to Positron Emission Tomography  

NASA Astrophysics Data System (ADS)

Currently inorganic scintillator detectors are used in all commercial Time of Flight Positron Emission Tomograph (TOF-PET) devices. The J-PET collaboration investigates a possibility of construction of a PET scanner from plastic scintillators which would allow for single bed imaging of the whole human body. This paper describes a novel method of hit-position reconstruction based on sampled signals and an example of an application of the method for a single module with a 30 cm long plastic strip, read out on both ends by Hamamatsu R4998 photomultipliers. The sampling scheme to generate a vector with samples of a PET event waveform with respect to four user-defined amplitudes is introduced. The experimental setup provides irradiation of a chosen position in the plastic scintillator strip with an annihilation gamma quanta of energy 511 keV. The statistical test for a multivariate normal (MVN) distribution of measured vectors at a given position is developed, and it is shown that signals sampled at four thresholds in a voltage domain are approximately normally distributed variables. With the presented method of a vector analysis made out of waveform samples acquired with four thresholds, we obtain a spatial resolution of about 1 cm and a timing resolution of about 80 ps (?).

Raczy?ski, L.; Moskal, P.; Kowalski, P.; Wi?licki, W.; Bednarski, T.; Bia?as, P.; Czerwi?ski, E.; Kap?on, ?.; Kochanowski, A.; Korcyl, G.; Kowal, J.; Kozik, T.; Krzemie?, W.; Kubicz, E.; Molenda, M.; Moskal, I.; Nied?wiecki, Sz.; Pa?ka, M.; Pawlik-Nied?wiecka, M.; Rudy, Z.; Salabura, P.; Sharma, N. G.; Silarski, M.; S?omski, A.; Smyrski, J.; Strzelecki, A.; Wieczorek, A.; Zieli?ski, M.; Zo?, N.

2014-11-01

358

Recent development in organic scintillators  

NASA Technical Reports Server (NTRS)

Discussion on recent developments of organic scintillators includes studies of organic compounds that form glass-like masses which scintillate and are stable at room temperature, correlations between molecular structure of organic scintillators and self-quenching, recently developed fast scintillators, and applications of liquid-scintillation counters.

Horrocks, D. L.; Wirth, H. O.

1969-01-01

359

A setup for probing ion molecule collision dynamics  

NASA Astrophysics Data System (ADS)

We describe a setup for studies of dissociation dynamics of multiply charged molecules formed due to highly charged ion impact. The setup consists of a multihit, position-sensitive, time of flight measurement system along with an electrostatic analyzer with offset detector. Brief description of different components of the setup and electronics for multihit data acquisition is presented in this paper. Coulomb explosion of multiply ionized N 2 and charge exchange studies on Ar with highly charged projectile ion is carried out to test the performance of the spectrometer and its multifold coincidence capabilities.

De, S.; Ghosh, P. N.; Roy, A.; Safvan, C. P.

2006-02-01

360

NUCLEAR RADIATION DETECTORS. Review Report No. 5  

Microsoft Academic Search

The book discusses several types of detectors, including ionization ; detectors, scintillation counters, Cherenkov counters, semiconductor devices, and ; crystalline detectors. Other types of detectors which are not discussed because ; of limited application include Wilson and bubble chambers. photographic ; emulsions, and chemical dosimeters. The principles of operation and proper use ; of the detectors are presented. The latest

Kazimierski

1962-01-01

361

Detector characterization for an inline PET scanner in hadrontherapy  

NASA Astrophysics Data System (ADS)

Our group at the "Institut de Physique Nucléaire de Lyon" (IPNL) is working on physics and detectors for medical imaging. We are presently developing a small animal Positron Emission Tomograph (PET) scanner prototype with an innovative slow control and data acquisition features, for a demonstration purpose and within the crystal clear international collaboration. We also investigate a feasibility study of an online PET dedicated for inline and in situ dose deposition control in hadrontherapy. Here, we present the characterization setup and method we used to calibrate the detector heads of our PET prototype. Each of these heads consists of a single block continuous scintillating LySO crystal coupled to a multi-anode photomultiplier equipped with its proper acquisition readout chain.

Taverne, Marina; Boutemeur, Madjid; Buthod, Anthony; Guigues, Laurent; Henriquet, Pierre; Lollierou, Julien; Ricol, Marie-Charlotte; Rosset-Lanchet, Rémi; Roubin, Mathieu; Saidi, Réda; Sappey-Marinier, Dominique; Testa, Etienne

2007-02-01

362

Arsenic activation neutron detector  

DOEpatents

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.

Jacobs, E.L.

1980-01-28

363

Arsenic activation neutron detector  

DOEpatents

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.

Jacobs, Eddy L. (Albuquerque, NM)

1981-01-01

364

The MINOS detectors  

SciTech Connect

The Main Injector Neutrino Oscillation Search (MINOS) experiment's primary goal is the precision measurement of the neutrino oscillation parameters in the atmospheric neutrino sector. This long-baseline experiment uses Fermilab's NuMI beam, measured with a Near Detector at Fermilab, and again 735 km later using a Far Detector in the Soudan Mine Underground Lab in northern Minnesota. The detectors are magnetized iron/scintillator calorimeters. The Far Detector has been operational for cosmic ray and atmospheric neutrino data from July of 2003, the Near Detector from September 2004, and the NuMI beam started in early 2005. This poster presents details of the two detectors.

Habig, A.; Grashorn, E.W.; /Minnesota U., Duluth

2005-07-01

365

Improved ?-? Coincidence Detector For Radioxenon Detection  

SciTech Connect

The Automated Radio-xenon Analyzer/Sampler (ARSA), built by Pacific Northwest National Laboratory (PNNL), can collect and detect several radioxenon isotopes. ARSA is very sensitive to 133Xe, 131mXe, 133mXe and 135Xe due to the compact high efficiency ?-? coincidence detector it uses. For this reason it is an excellent treaty monitoring and environmental sampling device. Although the system is shown to be both robust and reliable, based on several field tests, it is also complex due to a detailed photomultiplier tube gain matching regime. This complexity is a problem from a maintenance and quality assurance/quality control (QA/QC) standpoint. To reduce these issues a simplified ??? coincident detector has been developed. A comparison of three different well detectors has been completed. In addition, a new plastic scintillator gas cell was constructed. The new simplified detector system has been demonstrated to equal or better performance compared with the original ARSA design in spectral resolution and efficiency and significantly easier to setup and calibrate.

Cooper, Matthew W.; Carman, April J.; Hayes, James C.; Heimbigner, Tom R.; Hubbard, Charles W.; Litke, Kevin E.; McIntyre, Justin I.; Morris, Scott J.; Ripplinger, Michael D.; Suarez, Reynold

2005-08-31

366

Counterintuitive MCNPX Results for Scintillator Surface Roughness Effect  

SciTech Connect

We have reported on our recent MCNPX simulation results of energy deposition for a group of 8 scintillation detectors, coupled with various rough surface patterns. The MCNPX results generally favored the detectors with various rough surface patterns. The observed MCNPX results are not fully explained by this work.

None

2012-08-12

367

Adaptive spatially resolving detector for the extreme ultraviolet with absolute measuring capability  

SciTech Connect

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.

Benk, Markus; Bergmann, Klaus [Fraunhofer Institute for Laser Technology, Steinbachstrasse 15, D-52074 Aachen (Germany)

2009-03-15

368

Adaptive spatially resolving detector for the extreme ultraviolet with absolute measuring capability.  

PubMed

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

Benk, Markus; Bergmann, Klaus

2009-03-01

369

Pulsed neutron detector  

DOEpatents

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.

Robertson, deceased, J. Craig (late of Albuquerque, NM); Rowland, Mark S. (Livermore, CA)

1989-03-21

370

New electronically black neutron detectors  

SciTech Connect

Two neutron detectors are described that can function in a continuous radiation background. Both detectors identify neutrons by recording a proton recoil pulse followed by a characteristic capture pulse. This peculiar signature indicates that the neutron has lost all its energy in the scintillator. Resolutions and efficiencies have been measured for both detectors.

Drake, D.M.; Feldman, W.C.; Hurlbut, C.

1986-03-01

371

Measurement of ortho-positronium properties in liquid scintillators  

NASA Astrophysics Data System (ADS)

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.

Perasso, S.; Consolati, G.; Franco, D.; Hans, S.; Jollet, C.; Meregaglia, A.; Tonazzo, A.; Yeh, M.

2013-08-01

372

Measurement of ortho-Positronium Properties in Liquid Scintillators  

E-print Network

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.

S. Perasso; G. Consolati; D. Franco; S. Hans; C. Jollet; A. Meregaglia; A. Tonazzo; M. Yeh

2013-06-25

373

Measurement of ortho-Positronium Properties in Liquid Scintillators  

E-print Network

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.

Perasso, S; Franco, D; Hans, S; Jollet, C; Meregaglia, A; Tonazzo, A; Yeh, M

2013-01-01

374

Neutron Scattering Facility for Characterization of CRESST and EURECA Detectors at mK Temperatures  

E-print Network

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).

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

375

Majorana Thermosyphon Prototype Experimental Setup  

SciTech Connect

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.

Reid, Douglas J.; Guzman, Anthony D.; Munley, John T.

2011-08-01

376

Review on photonic crystal coatings for scintillators  

NASA Astrophysics Data System (ADS)

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.

Knapitsch, Arno; Lecoq, Paul

2014-11-01

377

The response of scintillators to heavy ions: 1, Plastics  

SciTech Connect

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.

McMahan, M.A.

1987-10-01

378

Performance of Water-based Liquid Scintillator  

NASA Astrophysics Data System (ADS)

Water-based detectors can only see the Cherenkov light from the fast moving charged particles, thus missing all the particles below the Cherenkov threshold. Detecting these below-threshold particles is important for various applications like the mobile detectors for the nuclear reactor monitoring, the search of the proton decay, and reconstruction of the neutrino energy and the reaction type by observing the vertex activity for both long and short baseline experiments. This detection can be achieved by using the Water-based Liquid Scintillator (WbLS), currently under development. It is based on the idea of dissolving the organic scintillator in water using special surfactants. This new material strives to achieve the novel detection techniques by combining the Cherenkov rings and scintillation light, as well as the total cost reduction compared to pure liquid scintillator (LS). We will present light yield measurements for the proton beam energies of 210MeV, 475MeV and 2000MeV for water, two different WbLS formulations (1% and 4%) and pure LS. These beam energies were chosen to study the contribution of the Cherenkov light to the total output.

Beznosko, Dmitriy

2013-04-01

379

Lanthanum Halide Nanoparticle Scintillators for Nuclear Radiation Detection  

SciTech Connect

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.

Guss, P. P., Guise, R., Yuan, D., Mukhopadhyay, S., O'Brien, R., Lowe, D.

2013-02-01

380

Lanthanum halide nanoparticle scintillators for nuclear radiation detection  

SciTech Connect

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.

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

381

Fluorescence decay-time constants in organic liquid scintillators  

SciTech Connect

The fluorescence decay-time constants have been measured for several scintillator mixtures based on phenyl-o-xylylethane (PXE) and linear alkylbenzene (LAB) solvents. The resulting values are of relevance for the physics performance of the proposed large-volume liquid scintillator detector Low Energy Neutrino Astronomy (LENA). In particular, the impact of the measured values to the search for proton decay via p{yields}K{sup +}{nu} is evaluated in this work.

Marrodan Undagoitia, T. [Physik-Department, Technische Universitaet Muenchen, James-Franck-Str., 85748 Garching (Germany); Physik-Institut, Universitaet Zuerich, Winterthurerstr. 190, 8057 Zuerich (Switzerland); Feilitzsch, F. von; Oberauer, L.; Potzel, W.; Ulrich, A.; Winter, J.; Wurm, M. [Physik-Department, Technische Universitaet Muenchen, James-Franck-Str., 85748 Garching (Germany)

2009-04-15

382

Fluorescence decay-time constants in organic liquid scintillators  

E-print Network

The fluorescence decay-time constants have been measured for several scintillator mixtures based on phenyl-o-xylylethane (PXE) and linear alkylbenzene (LAB) solvents. The resulting values are of relevance for the physics performance of the proposed large-volume liquid scintillator detector LENA (Low Energy Neutrino Astronomy). In particular, the impact of the measured values to the search for proton decay via p -> K+ antineutrino is evaluated in this work.

Undagoitia, T Marrodan; Oberauer, L; Potzel, W; Ulrich, A; Winter, J; Wurm, M; 10.1063/1.3112609

2009-01-01

383

Fluorescence decay-time constants in organic liquid scintillators  

NASA Astrophysics Data System (ADS)

The fluorescence decay-time constants have been measured for several scintillator mixtures based on phenyl-o-xylylethane (PXE) and linear alkylbenzene (LAB) solvents. The resulting values are of relevance for the physics performance of the proposed large-volume liquid scintillator detector Low Energy Neutrino Astronomy (LENA). In particular, the impact of the measured values to the search for proton decay via p ?K+?¯ is evaluated in this work.

Marrodán Undagoitia, T.; von Feilitzsch, F.; Oberauer, L.; Potzel, W.; Ulrich, A.; Winter, J.; Wurm, M.

2009-04-01

384

Cost-effective segmented scintillating converters for hard x rays  

NASA Astrophysics Data System (ADS)

Thick segmented scintillating converters coupled to optical imaging detectors offer the advantage of large area, high stopping power sensors for high energy x-ray digital imaging. The recent advent of high resolution and solid state optical sensors such as amorphous silicon arrays and CCD optical imaging detectors makes it feasible to build large, cost effective imaging arrays. This technology, however, shifts the sensor cost burden to the segmented scintillators needed for imaging. The required labor intensive fabrication of high resolution, large area hard x- ray converters results in high cost and questionable manufacturability on a large scale. We report on recent research of a new segmented x-ray imaging converter. This converter is fabricated using vacuum injection and crystal growth methods to induce defect free, high density scintillating fibers into a collimator matrix. This method has the potential to fabricate large area, thick segmented scintillators. Spatial resolution calculations of these scintillator injected collimators show that the optical light spreading is significantly reduced compared to single crystalline scintillators and sub-millimeter resolution x- ray images acquired with the segmented converter coupled to a cooled CCD camera provided the resolution to characterize the converter efficiency and noise. The proposed concept overcomes the above mentioned limitations by producing a cost-effective technique of fabricating large area x-ray scintillator converters with high stopping power and high spatial resolution. This technology will readily benefit diverse fields such as particle physics, astronomy, medicine, as well as industrial nuclear and non-destructive testing.

Vasile, Stefan A.; Gordon, Jeffrey S.; Klugerman, Mikhail; Nagarkar, Vivek V.; Squillante, Michael R.; Entine, Gerald; Watson, Scott; Kauppila, Todd J.

1996-07-01

385

Ionization and scintillation of nuclear recoils in gaseous xenon  

E-print Network

Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope $\\alpha$-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

J. Renner; V. M. Gehman; A. Goldschmidt; H. S. Matis; T. Miller; Y. Nakajima; D. Nygren; C. A. B. Oliveira; D. Shuman; V. Álvarez; F. I. G. Borges; S. Cárcel; J. Castel; S. Cebrián; A. Cervera; C. A. N. Conde; T. Dafni; T. H. V. T. Dias; J. Díaz; R. Esteve; P. Evtoukhovitch; L. M. P. Fernandes; P. Ferrario; A. L. Ferreira; E. D. C. Freitas; A. Gil; H. Gómez; J. J. Gómez-Cadenas; D. González-Díaz; R. M. Gutiérrez; J. Hauptman; J. A. Hernando Morata; D. C. Herrera; F. J. Iguaz; I. G. Irastorza; M. A. Jinete; L. Labarga; A. Laing; I. Liubarsky; J. A. M. Lopes; D. Lorca; M. Losada; G. Luzón; A. Marí; J. Martín-Albo; A. Martínez; A. Moiseenko; F. Monrabal; M. Monserrate; C. M. B. Monteiro; F. J. Mora; L. M. Moutinho; J. Muñoz Vidal; H. Natal da Luz; G. Navarro; M. Nebot-Guinot; R. Palma; J. Pérez; J. L. Pérez Aparicio; L. Ripoll; A. Rodríguez; J. Rodríguez; F. P. Santos; J. M. F. dos Santos; L. Seguí; L. Serra; A. Simón; C. Sofka; M. Sorel; J. F. Toledo; A. Tomás; J. Torrent; Z. Tsamalaidze; J. F. C. A. Veloso; J. A. Villar; R. C. Webb; J. White; N. Yahlali

2014-09-09

386

Ionization and scintillation of nuclear recoils in gaseous xenon  

E-print Network

Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope $\\alpha$-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

Renner, J; Goldschmidt, A; Matis, H S; Miller, T; Nakajima, Y; Nygren, D; Oliveira, C A B; Shuman, D; Álvarez, V; Borges, F I G; Cárcel, S; Castel, J; Cebrián, S; Cervera, A; Conde, C A N; Dafni, T; Dias, T H V T; Díaz, J; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferreira, A L; Freitas, E D C; Gil, A; Gómez, H; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Iguaz, F J; Irastorza, I G; Jinete, M A; Labarga, L; Laing, A; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzón, G; Marí, A; Martín-Albo, J; Martínez, A; Moiseenko, A; Monrabal, F; Monserrate, M; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; da Luz, H Natal; Navarro, G; Nebot-Guinot, M; Palma, R; Pérez, J; Aparicio, J L Pérez; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Seguí, L; Serra, L; Simón, A; Sofka, C; Sorel, M; Toledo, J F; Tomás, A; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Villar, J A; Webb, R C; White, J; Yahlali, N

2014-01-01

387

Trigger and electronics issues for scintillating fiber tracking  

SciTech Connect

Scintillating Fiber technology has made great advances and has demonstrated great promise for high speed charged particle tracking and triggering. The small detector sizes and fast scintillation floors available, make them very promising for use at high luminosity experiments at today`s and tomorrow`s colliding and fixed target experiments where high rate capability is essential. This paper will discuss some of the system aspects which should be considered by anyone attempting to design a scintillating fiber tracking system and high speed tracking trigger. As the reader will see, seemingly simple decisions can have far reaching effects on overall system performance.

Baumbaugh, A.E.

1994-01-01

388

XENON100 Dark Matter Search: Scintillation Response of Liquid Xenon to Electronic Recoils  

NASA Astrophysics Data System (ADS)

Dark matter is one of the missing pieces necessary to complete the puzzle of the universe. Numerous astrophysical observations at all scales suggest that 23 % of the universe is made of nonluminous, cold, collisionless, nonbaryonic, yet undiscovered dark matter. Weakly Interacting Massive Particles (WIMPs) are the most well-motivated dark matter candidates and significant efforts have been made to search for WIMPs. The XENON100 dark matter experiment is currently the most sensitive experiment in the global race for the first direct detection of WIMP dark matter. XENON100 is a dual-phase (liquid-gas) time projection chamber containing a total of 161 kg of liquid xenon (LXe) with a 62kg WIMP target mass. It has been built with radiopure materials to achieve an ultra-low electromagnetic background and operated at the Laboratori Nazionali del Gran Sasso in Italy. WIMPs are expected to scatter off xenon nuclei in the target volume. Simultaneous measurement of ionization and scintillation produced by nuclear recoils allows for the detection of WIMPs in XENON100. Data from the XENON100 experiment have resulted in the most stringent limits on the spin-independent elastic WIMP-nucleon scattering cross sections for most of the significant WIMP masses. As the experimental precision increases, a better understanding of the scintillation and ionization response of LXe to low energy (< 10 keV) particles is crucial for the interpretation of data from LXe based WIMP searches. A setup has been built and operated at Columbia University to measure the scintillation response of LXe to both electronic and nuclear recoils down to energies of a few keV, in particular for the XENON100 experiment. In this thesis, I present the research carried out in the context of the XENON100 dark matter search experiment. For the theoretical foundation of the XENON100 experiment, the first two chapters are dedicated to the motivation for and detection medium choice of the XENON100 experiment, respectively. A general review about dark matter focusing on WIMPs and their direct detection with liquid noble gas detectors is presented in Chap. 1. LXe as an attractive WIMP detection medium is explained in Chap. 2. The XENON100 detector design, the detector, and its subsystems are detailed in Chap. 3. The calibration of the detector and the characterized detector response used for the discrimination of a WIMP-like signal against background are explained in Chap. 4. In an effort to understand the background, anomalous electronic recoils were studied extensively and are described in Chap. 5. In order to obtain a better understanding of the electronic recoil background of XENON100, including an estimation of the electronic recoil background contribution, as well as to interpret dark matter results such as annual modulation, measurement of the scintillation yield of low-energy electrons in LXe was performed in 2011, with the dedicated setup mentioned above. The results from this measurement are discussed in Chap. 6. Finally, the results for the latest science data from XENON100 to search for WIMPs, comprising 225 live-days taken over 13 months during 2011 and 2012 are explained in Chap. 7.

Lim, Kyungeun Elizabeth

389

Reflectance of polytetrafluoroethylene for xenon scintillation light  

SciTech Connect

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.

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

390

Fast neutron detection with 6Li-loaded liquid scintillator  

NASA Astrophysics Data System (ADS)

We report on the development of a fast neutron detector using a liquid scintillator doped with enriched 6Li. The lithium was introduced in the form of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene-based liquid scintillator. A 6Li concentration of 0.15% by weight was obtained. A 125 mL glass cell was filled with the scintillator and irradiated with fission-source neutrons. Fast neutrons may produce recoil protons in the scintillator, and those neutrons that thermalize within the detector volume can be captured on the 6Li. The energy of the neutron may be determined by the light output from recoiling protons, and the capture of the delayed thermal neutron reduces background events. In this paper, we discuss the development of this 6Li-loaded liquid scintillator, demonstrate the operation of it in a detector, and compare its efficiency and capture lifetime with Monte Carlo simulations. Data from a boron-loaded plastic scintillator were acquired for comparison. We also present a pulse-shape discrimination method for differentiating between electronic and nuclear recoil events based on the Matusita distance between a normalized observed waveform and nuclear and electronic recoil template waveforms. The details of the measurements are discussed along with specifics of the data analysis and its comparison with the Monte Carlo simulation.

Fisher, B. M.; Abdurashitov, J. N.; Coakley, K. J.; Gavrin, V. N.; Gilliam, D. M.; Nico, J. S.; Shikhin, A. A.; Thompson, A. K.; Vecchia, D. F.; Yants, V. E.

2011-08-01

391

Nanophosphor composite scintillators comprising a polymer matrix  

DOEpatents

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.

Muenchausen, Ross Edward (Los Alamos, NM); Mckigney, Edward Allen (Los Alamos, NM); Gilbertson, Robert David (Los Alamos, NM)

2010-11-16

392

Scintillating plate calorimeter mechanical design  

Microsoft Academic Search

Progress on designs for compensating scintillator plate calorimeters will be presented. One design includes a lead composite absorber, fiber readout, and radiation hardened scintillator plates, and the second design has depleted uranium absorbers, wave length shifter plate readout, and scintillator plates. The lead absorber is cast with slots to accept the scintillator in the first design, while the depleted uranium

A. Buehring; N. Hill; T. Kirk; J. Nasiatka; E. Petereit; L. Price; J. Proudfoot; H. Spinka; D. Underwood; M. Burke; D. Hackworth; T. Hordubay; D. Marshik; D. Scherbarth; R. Swensrud

1990-01-01

393

Measurement of Low Energy Detection Efficiency of a Plastic Scintillator: Implications on the Lower Energy Limit and Sensitivity of a Hard X-Ray Focal Plane Compton Polarimeter  

NASA Astrophysics Data System (ADS)

The polarization measurements in X-rays offer a unique opportunity for the study of physical processes under the extreme conditions prevalent at compact X-ray sources, including gravitation, magnetic field, and temperature. Unfortunately, there has been no real progress in observational X-ray polarimetry thus far. Although photoelectron tracking-based X-ray polarimeters provide realistic prospects of polarimetric observations, they are effective in the soft X-rays only. With the advent of hard X-ray optics, it has become possible to design sensitive X-ray polarimeters in hard X-rays based on Compton scattering. An important point that should be carefully considered for the Compton polarimeters is the lower energy threshold of the active scatterer, which typically consists of a plastic scintillator due to its lowest effective atomic number. Therefore, an accurate understanding of the plastic scintillators energy threshold is essential to make a realistic estimate of the energy range and sensitivity of any Compton polarimeter. In this context, we set up an experiment to investigate the plastic scintillators behavior for very low energy deposition events. The experiment involves the detection of Compton scattered photons from a long, thin, plastic scintillator (a similar configuration as the eventual Compton polarimeter) by a high resolution CdTe detector at different scattering angles. We find that it is possible to detect energy deposition well below 1 keV, though with decreasing efficiency. We present detailed semianalytical modeling of our experimental setup and discuss the results in the context of the energy range and sensitivity of the Compton polarimeter involving plastic scintillators.

Chattopadhyay, T.; Vadawale, S. V.; Shanmugam, M.; Goyal, S. K.

2014-05-01

394

Gravitational Interstellar Scintillation  

E-print Network

Gravitation could modulate the interstellar scintillation of pulsars in a way that is analogous to refractive interstellar scintillation (RISS). While RISS occurs when a large ionized cloud crosses the pulsar line-of-sight, gravitational interstellar scintillation (GISS) occurs when a compact gravitational deflector lies very near to that line-of-sight. However, GISS differs from RISS in at least two important respects: It has a very distinctive and highly predictible time signature, and it is non-dispersive. We find two very different astronomical contexts where GISS could cause observable diffraction-pattern distortions: Highly inclined binary pulsars, and the kind of compact interstellar clouds suspected of causing extreme scattering events.

Redouane Al Fakir

2008-05-23

395

2052 IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 59, NO. 5, OCTOBER 2012 Nonproportionality and Scintillation Studies of  

E-print Network

to distinguish between different radioactive sources. For gamma-ray detection, scintillator materials with high nonproportionality, scintillation detectors, SrI . I. INTRODUCTION EFFICIENT radiation detectors must be able.gascon@stanford.edu; feigel@stan- ford.edu) R. Hawrami is with the Radiation Monitoring Devices, Inc., Watertown, MA 02472 USA

Curtarolo, Stefano

396

LabVIEW DAQ for NE213 Neutron Detector  

SciTech Connect

A neutron spectroscopy system, based on a NE213 liquid scintillation detector, to be placed at the Stanford Linear Accelerator Center to measure neutron spectra from a few MeV up to 800 MeV, beyond shielding. The NE213 scintillator, coupled with a Photomultiplier Tube (PMT), detects and converts radiation into current for signal processing. Signals are processed through Nuclear Instrument Modules (NIM) and Computer Automated Measurement and Control (CAMAC) modules. CAMAC is a computer automated data acquisition and handling system. Pulses are properly prepared and fed into an analog to digital converter (ADC), a standard CAMAC module. The ADC classifies the incoming analog pulses into 1 of 2048 digital channels. Data acquisition (DAQ) software based on LabVIEW, version 7.0, acquires and organizes data from the CAMAC ADC. The DAQ system presents a spectrum showing a relationship between pulse events and respective charge (digital channel number). Various photon sources, such as Co-60, Y-88, and AmBe-241, are used to calibrate the NE213 detector. For each source, a Compton edge and reference energy [units of MeVee] is obtained. A complete calibration curve results (at a given applied voltage to the PMT and pre-amplification gain) when the Compton edge and reference energy for each source is plotted. This project is focused to development of a DAQ system and control setup to collect and process information from a NE213 liquid scintillation detector. A manual is created to document the process of the development and interpretation of the LabVIEW-based DAQ system. Future high-energy neutron measurements can be referenced and normalized according to this calibration curve.

Al-Adeeb, Mohammed

2003-09-23

397

Secondary electron detector, with an extended life, for use in a scanning electron microscope  

Microsoft Academic Search

The plastic scintillator tip used as the secondary electron detector of a scanning microscope has a limited working life particularly with high electron beam currents. A detector with an extended life and capable of working up to beam currents of 3*10-6 A has been made by replacing the plastic scintillator tip with one made of a lithium glass scintillator.

D. C. Marshall; J. Stephen

1972-01-01

398

Scintillation properties of SrF2 and SrF2-Ce3+ crystals  

NASA Astrophysics Data System (ADS)

This Letter presents the results of measuring scintillation properties of pure SrF2 crystals and crystals activated by various concentrations of Ce3+ ions. The light yield of these materials is compared to that of the known scintillators NaI-Tl and CaF2-Eu2+. Strontium fluoride crystals activated with Ce3+ ions are found to be characterized by high light yield and to be promising materials for use in scintillation detectors employed for ?-ray well logging.

Shendrik, R. Yu.; Radzhabov, E. A.; Nepomnyashchikh, A. I.

2013-07-01

399

Response of liquid scintillator assemblies as a function of angular orientation  

NASA Astrophysics Data System (ADS)

Liquid scintillator detector assemblies contain an inert nitrogen expansion volume to allow for expansion of the liquid with changing temperature. Measurements and Geant4 Monte Carlo simulations are performed to study the dependence of pulse height distribution shapes as a function of detector angle for two liquid scintillators assemblies filled with 97% organic-liquid cocktail and a 3% expansion volume. A 12.7-cm diameter by 12.7-cm long and a 7.6-cm diameter by 9.1-cm long EJ-309 liquid scintillator assemblies are investigated using a 137Cs gamma-ray source. Aside from the differences in dimensions, the detector assemblies also differed in the design of the active detector volume: there is no light guide in the 12.7-cm-diameter detector assembly, whereas the 7.6-cm-diameter detector contains a BK7 light guide between the scintillation liquid and optical coupling to the photomultiplier tube. Results for the 12.7-cm-diameter detector show a decrease in the position of the Compton edge ranges from 4% to 40% at detector orientations where the expansion volume exists between scintillating medium and the photomultiplier tube. Results for the 7.6-cm-diameter detector show that the position of the Compton edge is relatively unaffected at all detector orientations due to the presence of light guide.

Naeem, S. F.; Scarpelli, M.; Miller, E.; Clarke, S. D.; Pozzi, S. A.

2014-06-01

400

A scintillation spectrometer with coincidence counting for aerosol analysis and source attribution  

NASA Astrophysics Data System (ADS)

A single particle counter analyzer is described comprising a sodium scintillation detector, potassium scintillation detector and flame ionization detector grouped about a hydrogen-air flame as excitation source. A microprocessor controlled data-logger counts and classifies the particles on the basis of coincident signals from several detectors. Populations of particles of sea salt, soil dust and particles from vegetative-burning yield discrete signatures. The development of the method of using element-specific-detectors and coincidence counting at the single particle level as a method of aerosol source attribution is illustrated for samples of urban aerosols.

Clark, N. J.

401

Particle detector spatial resolution  

DOEpatents

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.

Perez-Mendez, Victor (Berkeley, CA)

1992-01-01

402

Particle detector spatial resolution  

DOEpatents

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.

Perez-Mendez, V.

1992-12-15

403

Study of Avalanche Photodiodes as photosensors for liquid xenon scintillation light  

Microsoft Academic Search

We report on measurements with large area Avalanche Photodiodes (APD) as photodetectors for the ultraviolet scintillation light of liquid xenon (LXe). The APD, fabricated by Radiation Monitoring Devices Inc., was mounted inside the LXe detector, and scintillation light produced by Po-210 alpha particles was measured for a wide range of voltages and temperatures between 167 K and 178 K. The

Peter Shagin; Roman Gomez; Uwe Oberlack; Richard Farrell; Mickel McClish; Pricilla Cushman; Brian Sherwood

2006-01-01

404

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

405

Response of plastic scintillators to low-energy photons  

NASA Astrophysics Data System (ADS)

Diagnostic radiology typically uses x-ray beams between 25 and 150?kVp. Plastic scintillation detectors (PSDs) are potentially successful candidates as field dosimeters but careful selection of the scintillator is crucial. It has been demonstrated that they can suffer from energy dependence in the low-energy region, an undesirable dosimeter characteristic. This dependence is partially due to the nonlinear light yield of the scintillator to the low-energy electrons set in motion by the photon beam. In this work, PSDs made of PMMA, PVT or polystyrene were studied for the x-ray beam range 25 to 100?kVp. For each kVp data has been acquired for additional aluminium filtrations of 0.5, 1.0, 2.0 and 4.0?mm. Absolute dose in the point of measurement was obtained with an ionization chamber calibrated to dose in water. From the collected data, detector sensitivities were obtained as function of the beam kVp and additional filtration. Using Monte Carlo simulations relative scintillator sensitivities were computed. For some of the scintillators these sensitivities show strong energy-dependence for beam average energy below 35?keV for each additional filtration but fair constancy above. One of the scintillators (BC-404) has smaller energy-dependence at low photon average energy and could be considered a candidate for applications (like mammography) where beam energy has small span.

Peralta, Luis; Rêgo, Florbela

2014-08-01

406

High-resolution digital x-ray imaging system based on the scintillating plastic microfiber technology  

Microsoft Academic Search

The design and construction of a prototype high resolution digital x-ray imaging system, employing a novel scintillating microfiber detector as the x-ray imaging sensor is described. The fiber detector has an active imaging area of 5 cm X 5 cm and thickness of 1 cm. The optical image formed in the fiber detector is read out by a high resolution

Won Y. Choi; James K. Walker; Zhenxue Jing

1994-01-01

407

Bismuth germanate scintillators: applications in nuclear safeguards and health physics  

SciTech Connect

Bismuth germanate (BGO) scintillators are preferable to NaI(Tl) scintillators or germanium detectors for some applications in nuclear safeguards and health physics. The first system, which consists of eight scintillators and a computer-based data acquisition system, is very efficient. The second, which consists of one scintillator and a small analyzer, is less efficient but portable. A computer code that uses measured response functions and photopeak efficiencies, unfolds the BGO distributions measured with these systems to determine gamma-ray flux spectra and dose rates. One application of these systems is the accurate determination of flux spectra and dose rates from containers of uranium or plutonium. A second application determined these quantities from a replica of Little Boy, the device exploded over Hiroshima. 7 refs., 6 figs.

Moss, C.E.; Dowdy, E.J.; Lucas, M.C.

1985-05-01

408

Measurement of Propagation Time Dispersion in a Scintillator  

E-print Network

One contribution to the time resolution of a scintillation detector is the signal time spread due to path length variations of the detected photons from a point source. In an experimental study a rectangular scintillator was excited by means of a fast pulsed ultraviolet laser at different positions along its longitudinal axis. Timing measurements with a photomultiplier tube in a detection plane displaced from the scintillator end face showed a correlation between signal time and tube position indicating only a small distortion of photon angles during transmission. The data is in good agreement with a Monte Carlo simulation used to compute the average photon angle with respect to the detection plane and the average propagation time. Limitations on timing performance that arise from propagation time dispersion are expected for long and thin scintillators used in future particle identification systems.

P. Achenbach; C. Ayerbe Gayoso; J. Bernauer; R. Böhm; M. O. Distler; L. Doria; J. Friedrich; H. Merkel; U. Müller; L. Nungesser; J. Pochodzalla; S. Sánchez Majos; S. Schlimme; Th. Walcher; M. Weinriefer

2007-02-25

409

CaF2(Eu): an ``old'' scintillator revisited  

NASA Astrophysics Data System (ADS)

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.

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

410

Setup reduction approaches for machining  

SciTech Connect

Rapid setup is a common improvement approach in press working operations such as blanking and shearing. It has paid major dividends in the sheet metal industry. It also has been a major improvement thrust for high-production machining operations. However, the literature does not well cover all the setup operations and constraints for job shop work. This review provides some insight into the issues involved. It highlights the floor problems and provides insights for further improvement. The report is designed to provide a quick understanding of the issues.

Gillespie, L.K.

1997-04-01

411

New Measurement of the Scintillation Efficiency of Low-Energy Nuclear Recoils in Liquid Xenon  

E-print Network

Particle detectors that use liquid xenon (LXe) as detection medium are among the leading technologies in the search for dark matter weakly interacting massive particles (WIMPs). A key enabling element has been the low-energy detection threshold for recoiling nuclei produced by the interaction of WIMPs in LXe targets. In these detectors, the nuclear recoil energy scale is based on the LXe scintillation signal and thus requires knowledge of the relative scintillation efficiency of nuclear recoils, Leff. The uncertainty in Leff at low energies is the largest systematic uncertainty in the reported results from LXe WIMP searches at low masses. In the context of the XENON Dark Matter project, a new LXe scintillation detector has been designed and built specifically for the measurement of Leff at low energies, with an emphasis on maximizing the scintillation light detection efficiency to obtain the lowest possible energy threshold. We report new measurements of Leff at low energies performed with this detector. Our ...

Plante, G; Budnik, R; Choi, B; Giboni, K -L; Goetzke, L W; Lang, R F; Lim, K E; Fernandez, A J Melgarejo

2011-01-01