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Sample records for area plastic scintillator

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-05

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

  2. MeV X-ray imaging using plastic scintillating fiber area detectors: a simulation study.

    Science.gov (United States)

    Tang, Shi-Biao; Ma, Qingli; Yin, Zejie; Zhu, Daming

    2008-02-01

    Due to their low cost, flexibility, and convenience for long distance data transfer, plastic scintillating fibers (PSFs) have been increasingly used in building detectors or sensors for detecting various radiations and imaging. In this work, the possibility of using PSF coupled with charge-coupled devices (CCD) to build area detectors for X-ray imaging is studied using a Monte Carlo simulation. The focus is on X-ray imaging with energy from a few 100 keV to about 20 MeV. It is found that the efficiency of PSF in detecting X-ray in this energy range is low. The performance can be improved by coating a PSF with X-ray absorption layers and the MTF of the system is presented. It seems possible to build such area detectors with PSFs for imaging hard X-rays under certain environment.

  3. Plastic scintillator-based hodoscope for the characterization of large-area resistive plate chambers

    Indian Academy of Sciences (India)

    V K S KASHYAP; C YADAV; S T SEHGAL; R SEHGAL; R G THOMAS; L M PANT; A K MOHANTY

    2016-12-01

    A scintillator-based hodoscope is fully operational at Nuclear Physics Division, Bhabha Atomic Research Centre (NPD-BARC). It was used for characterizing the resistive plate chambers (RPCs) assembled for the RE4 upgrade for the compact muon solenoid (CMS) experiment, installed during the long shut-down (LS1) using cosmic muons. It has now been employed for R & D related to gas mixtures and glass RPCs for the Indiabased neutrino observatory (INO) and muon tomography studies. The hodoscope is equipped with gas flow lines,LV, HV and VME-based DAQ with multihit TDCs. CERN-based software was adapted, implemented and along with the cosmic trigger, was used to evaluate the functional parameters for the RPCs, such as efficiency, clustersize etc.

  4. Fluorescent compounds for plastic scintillation applications

    Energy Technology Data Exchange (ETDEWEB)

    Pla-Dalmau, A.; Bross, A.D.

    1994-04-01

    Several 2-(2{prime}-hydroxyphenyl)benzothiazole, -benzoxazole, and -benzimidazole derivatives have been prepared. Transmittance, fluorescence, light yield, and decay time characteristics of these compounds have been studied in a polystyrene matrix and evaluated for use in plastic scintillation detectors. Radiation damage studies utilizing a {sup 60}C source have also been performed.

  5. Plastic scintillators modifications for a selective radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, Matthieu; Bertrand, Guillaume H.V.; Carrel, Frederick; Coulon, Romain; Dumazert, Jonathan; Montbarbon, Eva; Sguerra, Fabien [CEA, LIST, Laboratoire Capteurs and Architectures electroniques, 91191 Gif-sur-Yvette cedex (France)

    2015-07-01

    Recent developments of plastic scintillators are reviewed, from January 2000 to June 2015. All examples are distributed into the main application, i.e. how the plastic scintillator was modified to enhance the detection towards a given radiation particle. The main characteristics of these newly created scintillators and their detection properties are given. (authors)

  6. Ultra-fast timing with plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Hoischen, Robert [Department of Physics, Lund University, S-22100 Lund (Sweden); Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Pietri, Stephane; Prokopowicz, Wawrzyniec; Schaffner, Henning; Gerl, Juergen; Wollersheim, Hans Juergen; Kurz, Nikolaus [Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Rudolph, Dirk [Department of Physics, Lund University, S-22100 Lund (Sweden)

    2009-07-01

    Fast timing detectors for time-of-flight measurements are essential identification tools for isotopes studied at fragment separators at major heavy-ion research facilities. While today's standard technique of utilizing a plastic scintillator read out by few photomultiplier tubes proofs to be efficient, it does not provide the required time resolution for future key experiments at, for example, the Super-FRS at FAIR. A common present-day approach is to use diamond detectors instead. While they do provide a better time resolution compared to scintillators, they are more difficult to use and far more expensive. Results from tests using a new design approach with standard materials will be presented. This leads to a much improved performance, but remains both cost-efficient, compact, and reliable. The design goals and how to accomplish them will be exemplified by the LYCCA (Lund-York-Cologne CAlorimeter) detector aiming for fast-beam experiments at HISPEC within NUSTAR.

  7. Plastic fiber scintillator response to fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Danly, C. R.; Sjue, S.; Wilde, C. H.; Merrill, F. E.; Haight, R. C. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2014-11-15

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

  8. Characterization of a new plastic scintillation material and comparison with liquid BC-501A scintillator

    OpenAIRE

    Poleshchuk, Oleksii

    2015-01-01

    In this work the capability of various scintillation materials to discriminate gamma rays and neutrons were studied. Also such basic properties of scintillators as light emission spectrum and light output were determined. The studied materials were BC-501A liquid scintillator and a plastic scintillator provided by CEA. An experimental setup consisting of detector shielding, analog and digital electronics and data acquisition system was built to study the neutron-gamma discrimination propertie...

  9. Buried plastic scintillator muon telescope (BATATA)

    Energy Technology Data Exchange (ETDEWEB)

    Alfaro, R. [Inst. de Fisica, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); De Donato, C.; D' Olivo, J.C.; Guzman, A.; Medina-Tanco, G. [Inst. de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Moreno Barbosa, E. [Fac. de Ciencias Fisico Matematicas, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico); Paic, G.; Patino Salazar, E. [Inst. de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Salazar Ibarguen, H. [Fac. de Ciencias Fisico Matematicas, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico); Sanchez, F.A., E-mail: federico.sanchez@nucleares.unam.m [Inst. de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Supanitsky, A.D. [Inst. de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Valdes-Galicia, J.F. [Inst. de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Vargas Trevino, A.D.; Vergara Limon, S. [Fac. de Ciencias de la Electronica, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico); Villasenor, L.M. [Inst. de Fisica y Matematicas, Universidad Michoacana de San Nicolas Hidalgo Morelia (Mexico); Observatorio Pierre Auger, Av. San Martin Norte 304 (5613) Malarguee, Prov. Mendoza (Argentina)

    2010-05-21

    Muon telescopes have multiple applications in the area of cosmic ray research. We are currently building such a detector with the objective of comparing the ground penetration of muon vs. electron-gamma signals originated in cosmic ray showers. The detector is composed by a set of three parallel dual-layer scintillator planes, buried at fixed depths ranging from 120 to 600g/cm{sup 2}. Each layer is 4m{sup 2} and is composed by 49 rectangular strips of 4cmx2m, oriented at a 90{sup 0} angle with respect to its companion layer, which gives an xy-coincidence pixel of 4x4cm{sup 2}. The scintillators are MINOS extruded polystyrene strips, with an embedded Bicron BC92 wavelength shifting (WLS) fibers, of 1.5 mm in diameter. Light is collected by Hamamatsu H7546B multi-anode PMTs of 64 pixels. The front-end (FE) electronics works in counting mode and signals are transmitted to the surface DAQ stage using low-voltage differential signaling (LVDS). Any strip signal above threshold opens a GPS-tagged 2{mu}s data collection window. Data, including signal and background, are acquired by a system of FPGA (Spartan 2E) boards and a single-board computer (TS7800).

  10. Buried plastic scintillator muon telescope (BATATA)

    Science.gov (United States)

    Alfaro, R.; de Donato, C.; D'Olivo, J. C.; Guzmán, A.; Medina-Tanco, G.; Moreno Barbosa, E.; Paic, G.; Patiño Salazar, E.; Salazar Ibarguen, H.; Sánchez, F. A.; Supanitsky, A. D.; Valdés-Galicia, J. F.; Vargas Treviño, A. D.; Vergara Limón, S.; Villaseñor, L. M.; Auger Collaboration

    2010-05-01

    Muon telescopes have multiple applications in the area of cosmic ray research. We are currently building such a detector with the objective of comparing the ground penetration of muon vs. electron-gamma signals originated in cosmic ray showers. The detector is composed by a set of three parallel dual-layer scintillator planes, buried at fixed depths ranging from 120 to 600g/cm2. Each layer is 4m2 and is composed by 49 rectangular strips of 4cm×2m, oriented at a 90∘ angle with respect to its companion layer, which gives an xy-coincidence pixel of 4×4cm2. The scintillators are MINOS extruded polystyrene strips, with an embedded Bicron BC92 wavelength shifting (WLS) fibers, of 1.5 mm in diameter. Light is collected by Hamamatsu H7546B multi-anode PMTs of 64 pixels. The front-end (FE) electronics works in counting mode and signals are transmitted to the surface DAQ stage using low-voltage differential signaling (LVDS). Any strip signal above threshold opens a GPS-tagged 2μs data collection window. Data, including signal and background, are acquired by a system of FPGA (Spartan 2E) boards and a single-board computer (TS7800).

  11. B-Loaded Plastic Scintillator on the Base of Polystyrene

    CERN Document Server

    Brudanin, V B; Nemchenok, I B; Smolnikov, A A

    2000-01-01

    A method to produce polystyrene-based plastic scintillators with boron concentration from 0.38 to 5.0% of boron have been developed. o-Carborane was used as B-containing additive. The results of investigations of the optical, spectral and scintillation characteristics are presented and discussed. It is shown that 5% B-loaded scintillator has a light output as much as 70% relative to the unloaded one. High efficiency for thermal neutron registration achieved for produced samples makes it possible to use such scintillators in complex neutron high sensitive spectrometers. Measured level of radioactive contamination in this scintillation materials is good enough for using the B-loaded scintillators in the proposed large scale neutrino experiments.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mabe, Andrew N., E-mail: mabe2@llnl.gov; Glenn, Andrew M.; Carman, M. Leslie; Zaitseva, Natalia P.; Payne, Stephen A.

    2016-01-11

    Transparent plastic scintillators with pulse shape discrimination containing {sup 6}Li salicylate have been synthesized by bulk polymerization with a maximum {sup 6}Li loading of 0.40 wt%. Photoluminescence and scintillation responses to gamma-rays and neutrons are reported herein. Plastics containing {sup 6}Li salicylate exhibit higher light yields and permit a higher loading of {sup 6}Li as compared to previously reported plastics based on lithium 3-phenylsalicylate. However, pulse shape discrimination performance is reduced in lithium salicylate plastics due to the requirement of adding more nonaromatic monomers to the polymer matrix as compared to those based on lithium 3-phenylsalicylate. Reduction in light yield and pulse shape discrimination performance in lithium-loaded plastics as compared to pulse shape discrimination plastics without lithium is interpreted in terms of energy transfer interference by the aromatic lithium salts. - Highlights: • Plastic scintillator with 0.4% {sup 6}Li loading is reported using lithium salicylate. • Influence of lithium salts on the scintillation mechanism is explored. • New lithium-loaded scintillator provides improved light yield and reduced cost.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-01

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

  14. Gadolinium loaded plastic scintillators for high efficiency neutron detection

    Science.gov (United States)

    Ovechkina, Lena; Riley, Kent; Miller, Stuart; Bell, Zane; Nagarkar, Vivek

    2009-08-01

    Gadolinium has the highest thermal neutron absorption cross section of any naturally occurring element, and emits conversion electrons as well as atomic X-rays in over 50% of its neutron captures, which makes it a useful dopant in scintillators for detecting thermal neutrons. Gadolinium isopropoxide was studied as a possible dopant for styrene-based plastic scintillators as a convenient and inexpensive method to produce high-efficiency thermal neutron detectors. Plastic scintillators with gadolinium weight concentrations of up to 3% were transparent, uniform and defect-free and were characterized with spectral measurements performed under x-ray and neutron irradiation. The new material has the same characteristic emission of styrene with a maximum at approximately 425 nm, and a light output of 76% relative to the undoped plastic. A 13 mm thick sample containing 0.5% gadolinium by weight detected 46% of incident thermal neutrons, which makes this an attractive material for a variety of applications.

  15. Plastic scintillators for positron emission tomography obtained by the bulk polymerization method

    CERN Document Server

    Kapłon, Łukasz; Molenda, Marcin; Moskal, Paweł; Wieczorek, Anna; Bednarski, Tomasz; Białas, Piotr; Czerwiński, Eryk; Korcyl, Grzegorz; Kowal, Jakub; Kowalski, Paweł; Kozik, Tomasz; Krzemień, Wojciech; Niedźwiecki, Szymon; Pałka, Marek; Pawlik, Monika; Raczyński, Lech; Rudy, Zbigniew; Salabura, Piotr; Gupta-Sharma, Neha; Silarski, Michał; Słomski, Artur; Smyrski, Jerzy; Strzelecki, Adam; Wiślicki, Wojciech; Zieliński, Marcin; Zoń, Natalia

    2015-01-01

    This paper describes three methods regarding the production of plastic scintillators. One method appears to be suitable for the manufacturing of plastic scintillator, revealing properties which fulfill the requirements of novel positron emission tomography scanners based on plastic scintillators. The key parameters of the manufacturing process are determined and discussed.

  16. Development of Plastic Scintillator Detector Array Based on SPMT

    Institute of Scientific and Technical Information of China (English)

    SU; Dan; ZHANG; Guo-guang; ZHAO; Xiao; FENG; Shu-qiang; ZHANG; Shuai

    2015-01-01

    Silicon photoelectric multiplier tuber(SPMT)is made of silicon chip,which can collect weak optical signal(Fig.1).When visible light irradiates SPMT,SPMT can change optical signal to electrical signal.The electrical signal size can be obtained through detecting optical signal size.When putting plastic scintillator before

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jun [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Ding, Yunyu [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhu, Jiayi [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Qi, Di [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Su, Ming [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Xu, Yewei; Bi, Yutie [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Lin, Runxiong, E-mail: qdlrx@qust.edu.cn [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhang, Lin, E-mail: zhlmy@sina.com [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

    2016-05-01

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

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

    Science.gov (United States)

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

    2016-05-01

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

  19. Monte Carlo calculation of radiation energy absorbed in plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Mainardi, R.T.; Bonzi, E.V. [Universidad Nacional de Cordoba (Argentina). Facultad de Matematica, Astronomia y Fisica

    1995-05-01

    Monte Carlo calculations of the rate of absorbed energy from a photon beam were carried out to compare the response of commercial plastic scintillators with that of air in the energy region below 1 MeV. We have found that for photon energies above 100 keV, the response of different kinds of plastics is proportional to that of air, while below this value of energy, we have obtained differences between the responses of plastics and air. In a literature search, we have also found discrepancies with other authors as well as among them. In this paper, we investigate the possibilities of eliminating these differences and explaining discrepancies. We found that doping a plastic scintillator with silicon makes the composite materials behave like air from 2 keV up to 600 keV, making the ratio of absorbed energy constant. This energy region is of interest in radiology and surface radiotherapy and we conclude that a plastic scintillator with truly air-equivalent behavior is of importance to carry out more precise dosimetry. Other elements such as fluorine and magnesium were also considered, but silicon was found to be more appropriate due to its greater atomic number and its interchangeability with carbon in hydrocarbon molecules. (author).

  20. Response of plastic scintillators to low-energy photons.

    Science.gov (United States)

    Peralta, Luis; Rêgo, Florbela

    2014-08-21

    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.

  1. First approach to radionuclide mixtures quantification by using plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Tarancon, A. [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Garcia, J.F. [Departament de Pintura, Universitat de Barcelona, Pau Gargallo 4, E-08028 Barcelona (Spain)]. E-mail: jfgarcia@ub.edu; Rauret, G. [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain)

    2007-05-08

    Recent studies have evaluated the capability of plastic scintillation (PS) as an alternative to liquid scintillation (LS) in radionuclide activity determination without mixed waste production. In order to complete the comparison, we now assess the extent to which PS can be used to quantify mixtures of radionuclides and the influence of the diameter of the plastic scintillation beads in detection efficiency. The results show that the detection efficiency decreases and the spectrum shrink to lower energies when the size of the plastic scintillation beads increases, and that the lower the energy of the beta particle, the greater the variation takes place. Similar behaviour has been observed for beta-gamma and alpha emitters. Two scenarios for the quantification of mixtures are considered, one including two radionuclides ({sup 14}C and {sup 60}Co) whose spectra do not overlap significantly, and the other including two radionuclides ({sup 137}Cs and {sup 90}Sr/{sup 90}Y), where the spectra of one the isotopes is totally overlapped by the other The calculation has been performed by using the conventional window selection procedure and a new approach in which the selected windows correspond to those with lower quantification errors. Relative errors obtained using the proposed approach (less than 10%) are lower than those of the conventional procedure, even when a radionuclide is completely overlapped, except for those samples with extreme activity ratios that were not included in the window optimization process.

  2. A remote reactor monitoring with plastic scintillation detector

    CERN Document Server

    Georgadze, A Sh; Ponkratenko, O A; Litvinov, D A

    2016-01-01

    Conceiving the possibility of using plastic scintillator bars as robust detectors for antineutrino detection for the remote reactor monitoring and nuclear safeguard application we study expected basic performance by Monte Carlo simulation. We present preliminary results for a 1 m3 highly segmented detector made of 100 rectangular scintillation bars forming an array which is sandwiched at both sides by the continuous light guides enabling light sharing between all photo detectors. Light detection efficiency is calculated for several light collection configurations, considering different scintillation block geometries and number of photo-detectors. The photo-detectors signals are forming the specific hit pattern, which is characterizing the impinging particle. The statistical analysis of hit patterns allows effectively select antineutrino events and rejects backgrounds. To evaluate detector sensitivity to fuel isotopic composition evolution during fuel burning cycle we have calculated antineutrino spectra. The ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Woolf, Richard S., E-mail: richard.woolf@nrl.navy.mil [High Energy Space Environment Branch, Space Science Division, U. S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375 (United States); Hutcheson, Anthony L., E-mail: anthony.hutcheson@nrl.navy.mil [High Energy Space Environment Branch, Space Science Division, U. S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375 (United States); Gwon, Chul, E-mail: chul.gwon@nrl.navy.mil [High Energy Space Environment Branch, Space Science Division, U. S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375 (United States); Phlips, Bernard F., E-mail: bernard.phlips@nrl.navy.mil [High Energy Space Environment Branch, Space Science Division, U. S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375 (United States); Wulf, Eric A., E-mail: eric.wulf@nrl.navy.mil [High Energy Space Environment Branch, Space Science Division, U. S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375 (United States)

    2015-06-01

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

  4. Systematic evaluation of photodetector performance for plastic scintillation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, Jonathan, E-mail: jonathan.boivin.1@ulaval.ca; Beaulieu, Luc [Département de Physique, de Génie physique et d’Optique, et Centre de recherche sur le cancer, Université Laval, Québec, Québec G1V 0A6, Canada and Département de Radio-Oncologie et Axe oncologie du Centre de recherche du CHU de Québec, CHU de Québec, Québec, Québec G1R 2J6 (Canada); Beddar, Sam [Department of Radiation Physics, University of Texas, MD Anderson Cancer Center, Houston, Texas 77030 (United States); Guillemette, Maxime [Département de Physique, de Génie physique et d’Optique, Université Laval, Québec, Québec G1V 0A6, Canada and Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Québec G1V 4G5 (Canada)

    2015-11-15

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

  5. Application of a free parameter model to plastic scintillation samples

    Energy Technology Data Exchange (ETDEWEB)

    Tarancon Sanz, Alex, E-mail: alex.tarancon@ub.edu [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Kossert, Karsten, E-mail: Karsten.Kossert@ptb.de [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany)

    2011-08-21

    In liquid scintillation (LS) counting, the CIEMAT/NIST efficiency tracing method and the triple-to-double coincidence ratio (TDCR) method have proved their worth for reliable activity measurements of a number of radionuclides. In this paper, an extended approach to apply a free-parameter model to samples containing a mixture of solid plastic scintillation microspheres and radioactive aqueous solutions is presented. Several beta-emitting radionuclides were measured in a TDCR system at PTB. For the application of the free parameter model, the energy loss in the aqueous phase must be taken into account, since this portion of the particle energy does not contribute to the creation of scintillation light. The energy deposit in the aqueous phase is determined by means of Monte Carlo calculations applying the PENELOPE software package. To this end, great efforts were made to model the geometry of the samples. Finally, a new geometry parameter was defined, which was determined by means of a tracer radionuclide with known activity. This makes the analysis of experimental TDCR data of other radionuclides possible. The deviations between the determined activity concentrations and reference values were found to be lower than 3%. The outcome of this research work is also important for a better understanding of liquid scintillation counting. In particular the influence of (inverse) micelles, i.e. the aqueous spaces embedded in the organic scintillation cocktail, can be investigated. The new approach makes clear that it is important to take the energy loss in the aqueous phase into account. In particular for radionuclides emitting low-energy electrons (e.g. M-Auger electrons from {sup 125}I), this effect can be very important.

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

    Beaulieu, Luc; Beddar, Sam

    2016-10-01

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

  8. Measurement of gamma quantum interaction point in plastic scintillator with WLS strips

    Science.gov (United States)

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

    2017-04-01

    The feasibility of measuring the aśxial coordinate of a gamma quantum interaction point in a plastic scintillator bar via the detection of scintillation photons escaping from the scintillator with an array of wavelength-shifting (WLS) strips is demonstrated. Using a test set-up comprising a BC-420 scintillator bar and an array of sixteen BC-482A WLS strips we achieved a spatial resolution of 5 mm (σ) for annihilation photons from a 22Na isotope. The studied method can be used to improve the spatial resolution of a plastic-scintillator-based PET scanner which is being developed by the J-PET collaboration.

  9. Quenching Factor for Low Energy Nuclear Recoils in a Plastic Scintillator

    OpenAIRE

    Reichhart, L.; Akimov, D. Yu.; Araujo, H. M.; Barnes, E. J.; Belov, V. A.; Burenkov, A. A.; Chepel, V.; Currie, A; DeViveiros, L.; Edwards, B.; Francis, V.; Ghag, C.; Hollingsworth, A.; Horn, M.; Kalmus, G.E.

    2011-01-01

    Plastic scintillators are widely used in industry, medicine and scientific research, including nuclear and particle physics. Although one of their most common applications is in neutron detection, experimental data on their response to low-energy nuclear recoils are scarce. Here, the relative scintillation efficiency for neutron-induced nuclear recoils in a polystyrene-based plastic scintillator (UPS-923A) is presented, exploring recoil energies between 125 keV and 850 keV. Monte Carlo simula...

  10. Mixture quantification using PLS in plastic scintillation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Bagan, H.; Tarancon, A.; Rauret, G. [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Garcia, J.F., E-mail: jfgarcia@ub.ed [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain)

    2011-06-15

    This article reports the capability of plastic scintillation (PS) combined with multivariate calibration (Partial least squares; PLS) to detect and quantify alpha and beta emitters in mixtures. While several attempts have been made with this purpose in mind using liquid scintillation (LS), no attempt was done using PS that has the great advantage of not producing mixed waste after the measurements are performed. Following this objective, ternary mixtures of alpha and beta emitters ({sup 241}Am, {sup 137}Cs and {sup 90}Sr/{sup 90}Y) have been quantified. Procedure optimisation has evaluated the use of the net spectra or the sample spectra, the inclusion of different spectra obtained at different values of the Pulse Shape Analysis parameter and the application of the PLS1 or PLS2 algorithms. The conclusions show that the use of PS+PLS2 applied to the sample spectra, without the use of any pulse shape discrimination, allows quantification of the activities with relative errors less than 10% in most of the cases. This procedure not only allows quantification of mixtures but also reduces measurement time (no blanks are required) and the application of this procedure does not require detectors that include the pulse shape analysis parameter.

  11. Scanners for the quality contol of scintillating plastic fibres

    CERN Document Server

    Rodigues, Ana Barbara; Garnier, Francois; Giudici, Pierre-Ange; Greim, Roman; Hebler, Philip; Joram, Christian; Kirn, Thomas; Pierschel, Gerhard; Schateikis, Tobias; Stevens, Holger; Bachlechner, Andreas; Deckenhoff, Mirco; Karpinski, Waclaw; Kruse, Florian; Schultz Von Dratzig, Arndt; Schwering, Georg; Swientek, Krzysztof Piotr; Wlochal, Michael

    2015-01-01

    The use of scintillating plastic fibres in the SciFi tracker requires rigorous quality control. The fibre diameter and in particular local variations in form of bumps and necks have an impact on the regularity of the winding pattern and hence the spatial resolution. Defects in the fibre cladding lead to light losses and inter-fibre cross talk. Machines have been developed which allow scanning at high throughput of the fibre diameter and the integrity of the cladding. We describe the design principles and implementations of these machines and illustrate their performance. While these machines allow to identify and quantify performance issues of the prototype fibres, they will also play a major role during the series production of the SciFi tracker. If needed, the capacity of the machines allows scanning of the full production volume.

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

    CERN Document Server

    Jivan, Harshna; The ATLAS collaboration

    2014-01-01

    The Tile Calorimeter of the ATLAS detector, is a hadronic calorimeter responsible for detecting hadrons as well as accommodating for the missing transverse energy that result from the p-p collisions within the LHC. Plastic scintillators form an integral component of this calorimeter due to their ability to undergo prompt fluorescence when exposed to ionising particles. The scintillators employed are specifically chosen for their properties of high optical transmission and fast rise and decay time which enables efficient data capture since fast signal pulses can be generated. The main draw-back of plastic scintillators however is their susceptibility to radiation damage. The damage caused by radiation exposure reduces the scintillation light yield and introduces an error into the time-of flight data acquired. During Run 1 of the LHC data taking period, plastic scintillators employed within the GAP region between the Tile Calorimeter’s central and extended barrels sustained a significant amount of damage. Wit...

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

    Science.gov (United States)

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

    2016-11-01

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

  14. Surface coatings as xenon diffusion barriers on plastic scintillators : Improving Nuclear-Test-Ban Treaty verification

    OpenAIRE

    Bläckberg, Lisa

    2011-01-01

    This thesis investigates the ability of transparent surface coatings to reduce xenon diffusion into plastic scintillators. The motivation for the work is improved radioxenon monitoring equipment, used with in the framework of the verification regime of the Comprehensive Nuclear-Test-Ban Treaty. A large part of the equipment used in this context incorporates plastic scintillators which are in direct contact with the radioactive gas to be detected. One problem with such setup is that radioxenon...

  15. Study on calibration of neutron efficiency and relative photo-yield of plastic scintillator

    CERN Document Server

    Peng Tai Ping; Li Ru Rong; Zhang Jian Hua; Luo Xiao Bing; Xia Yi Jun; Yang Zhi Hu

    2002-01-01

    A method used for the calibration of neutron efficiency and the relative photo yield of plastic scintillator is studied. T(p, n) and D(d, n) reactions are used as neutron resources. The neutron efficiencies and the relative photo yields of plastic scintillators 1421 (40 mm in diameter and 5 mm in thickness) and determined in the neutron energy range of 0.655-5 MeV

  16. Application of WLS strips for position determination in Strip PET tomograph based on plastic scintillators

    CERN Document Server

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

    2013-01-01

    A method of determination of a gamma quantum absorption point in a plastic scintillator block using a matrix of wavelength-shifting (WLS) strips is proposed. Application of this method for improvement of position resolution in newly proposed PET detectors based on plastic scintillators is presented. The method enables to reduce parallax errors in reconstruction of images which occurs in the presently used Positron Emission Tomography scanners.

  17. A simple technique for gamma ray and cosmic ray spectroscopy using plastic scintillator

    CERN Document Server

    Nandan, Akhilesh P; Neog, Himangshu; Bhuyan, M R; Biswas, S; Mahapatra, S; Mohanty, B; Mohanty, Rudranarayan; Rout, Subasha; Sahu, P K; Sahu, S; Sakthivel, V A; Samal, P K

    2014-01-01

    A new and simple technique has been developed using plastic scintillator detectors for gamma ray and cosmic ray spectroscopy without single channel analyzer (SCA) or multichannel analyzer (MCA). In these experiments only a leading edge discriminator (LED) and NIM scalers have been used. Energy calibration of gamma spectra in plastic scintillators has been done using Co60 and Cs137 sources. The details experimental technique, analysis procedure and experimental results has been presented in this article.

  18. A mathematical formalism for hyperspectral, multipoint plastic scintillation detectors.

    Science.gov (United States)

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

    2012-11-07

    The aim of this paper is to generalize and extend the mathematical formalism used with plastic scintillation detectors (PSDs). By doing so, we show the feasibility of multi-point PSD. The new formalism is based on the sole hypothesis that a PSD optical signal is a linear superposition of spectra. Two calibration scenarios were developed. Both involve solving a linear equation of the form Y = XB, but the process and input data depend on the information available on the detector system. Simulations were carried out to validate both scenarios and demonstrate the advantages of the new formalism. In this paper, we prove the following results. (1) Multi-point PSDs are feasible. Simulations have shown that six different spectra could be resolved accurately even in the presence of up to 10% Gaussian noise. (2) The new formalism leads to more precise PSD measurements. (3) By using the condition number of the measurement matrix, the ideal sets of calibration measurements can be identified. (4) By using principal component analysis it was possible to identify the best set of wavelength filters. We have shown through numerical simulations that multi-point detectors are feasible. This has potential for applications such as in vivo dose verification. Furthermore, our new formalism can be used to improve the robustness and ease of use of PSDs.

  19. Monte Carlo calculations of efficiencies for photon interactions in plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Bonzi, E.V.; Mainardi, R.T. (Facultad de Matematica, Astronomia y Fisica, Univ. Nacional de Cordoba (Argentina))

    1992-12-01

    Energy absorption and total peak efficiencies for plastic scintillators have been calculated by means of the Monte Carlo method. These results are of interest for potential uses of plastic scintillators as dosimetric or spectrometric devices. The calculations were carried out for photon energies from 2 keV up to 1 MeV. We considered all of the physical effects involved in each range of energy, photoelectric, Compton and Rayleigh. As a consistency test the same code was used to calculate efficiencies for NaI scintillators. The agreement with results published previously by other authors, within calculated errors, is very satisfactory. (orig.).

  20. Study of timing characteristics of a 3 m long plastic scintillator counter using waveform digitizers

    CERN Document Server

    Blondel, A; Dubreuil, A; Khotyantsev, A; Korzenev, A; Maalmi, J; Mefodev, A; Mermod, P; Noah, E

    2016-01-01

    A plastic scintillator bar with dimensions 3 m x 2.5 cm x 11 cm was exposed to a focused muon beam to study its light yield and timing characteristics as a function of position and angle of incidence. The scintillating light was read out at both ends by photomultiplier tubes whose pulse shapes were recorded by waveform digitizers. Results obtained with the WAVECATCHER and SAMPIC digitizers are analyzed and compared. A comprehensive discussion of the various factors affecting the timing resolution is presented. Prospects for applications of plastic scintillator technology in large-scale particle physics detectors with timing resolution around 100 ps are provided in light of the results.

  1. The plastic scintillator detector calibration circuit for DAMPE

    Science.gov (United States)

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

    2016-07-01

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

  2. Optimization of plastic scintillator thicknesses for online beta/gamma detection

    Directory of Open Access Journals (Sweden)

    Pourtangestani K.

    2012-04-01

    Full Text Available For efficient beta detection in a mixed beta gamma field, Monte Carlo simulation models have been built to optimize the thickness of a plastic scintillator, used in a whole body monitor. The simulation has been performed using the MCNP/X code for different thicknesses of plastic scintillator from 150 μm to 600 μm. The relationship between the thickness of the scintillator and the efficiency of the detector has been analyzed. For 150 μm thickness, an experimental investigation has been conducted with different beta sources at different positions on the scintillator and the counting efficiency of the unit has been measured. Evaluated data along with experimental ones have been discussed. A thickness of 300 μm to 500 μm has been found to be the optimum thickness for high efficiency beta detection in the presence of low energy gamma-rays.

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

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, M., E-mail: minori@hep.sc.niigata-u.ac.jp [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Katsumata, M. [Faculty of Science, Physics Department, Niigata University, Niigata 950-2181 (Japan); Ono, H. [Nippon Dental University, School of Life Dentistry at Niigata, Niigata 951-8580 (Japan); Suzuki, T. [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Miyata, H. [Faculty of Science, Physics Department, Niigata University, Niigata 950-2181 (Japan); Itoh, Y.; Ishida, K. [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Tamura, M.; Yamaguchi, Y. [Carlit Holdings Co., Ltd., Chiyoda, Tokyo 101-0024 (Japan)

    2015-01-11

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

  4. Scintillation Particle Detectors Based on Plastic Optical Fibres and Microfluidics

    CERN Document Server

    Mapelli, Alessandro; Renaud, Philippe

    2011-01-01

    This thesis presents the design, development, and experimental validation of two types of scintillation particle detectors with high spatial resolution. The first one is based on the well established scintillating fibre technology. It will complement the ATLAS (A Toroidal Large ApparatuS) detector at the CERN Large Hadron Collider (LHC). The second detector consists in a microfabricated device used to demonstrate the principle of operation of a novel type of scintillation detector based on microfluidics. The first part of the thesis presents the work performed on a scintillating fibre tracking system for the ATLAS experiment. It will measure the trajectory of protons elastically scattered at very small angles to determine the absolute luminosity of the CERN LHC collider at the ATLAS interaction point. The luminosity of an accelerator characterizes its performance. It is a process-independent parameter that is completely determined by the properties of the colliding beams and it relates the cross section of a ...

  5. Discrimination methods between neutron and gamma rays for boron loaded plastic scintillators

    CERN Document Server

    Normand, S; Haan, S; Louvel, M

    2002-01-01

    Boron loaded plastic scintillators exhibit interesting properties for neutron detection in nuclear waste management and especially in investigating the amount of fissile materials when enclosed in waste containers. Combining a high thermal neutron efficiency and a low mean neutron lifetime, they are suitable in neutron multiplicity counting. However, due to their high sensitivity to gamma rays, pulse shape discrimination methods need to be developed in order to optimize the passive neutron assay measurement. From the knowledge of their physical properties, it is possible to separate the three kinds of particles that have interacted in the boron loaded plastic scintillator (gamma, fast neutron and thermal neutron). For this purpose, we have developed and compared the two well known discrimination methods (zero crossing and charge comparison) applied for the first time to boron loaded plastic scintillator. The setup for the zero crossing discrimination method and the charge comparison methods is thoroughly expl...

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

    Science.gov (United States)

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

    2016-07-01

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

  7. Development of a fast plastic scintillation detector with time resolution of less than 10 ps

    CERN Document Server

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

    2016-01-01

    Timing-pick up detectors with excellent timing resolutions are essential in many modern nuclear physics experiments. Aiming to develop a Time-Of-Flight system with precision down to about 10 ps, we have made a systematic study of the timing characteristic of TOF detectors, which consist of several combinations of plastic scintillators and photomultiplier tubes. With the conventional electronics, the best timing resolution of about 5.1 ps ({\\sigma}) has been achieved for detectors with an area size of 3x1 cm2. It is found that for data digitalization a combination of TAC and ADC can achieve a better time resolution than currently available TDC. Simultaneously measurements of both time and pulse height are very valuable for correction of time-walk effect.

  8. Fast timing with plastic scintillators for in-beam heavy-ion spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hoischen, R., E-mail: robert.hoischen@nuclear.lu.se [Department of Physics, Lund University, SE-22100 Lund (Sweden); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Pietri, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Rudolph, D. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Prokopowicz, W.; Schaffner, H. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Emde, S. [Lehrstuhl fuer Operations Management, Friedrich-Schiller-Universitaet Jena, D-07743 Jena (Germany); Golubev, P. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Wendt, A. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany); Kurz, N.; Wollersheim, H.J.; Gerl, J. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany)

    2011-10-21

    The design, R and D, and testing of a new plastic-scintillator detector for Time-of-Flight measurements with relativistic heavy-ion beams are presented. A design approach using 32 independent precise timing measurements of the same physical event is followed. This is different from the conventional scheme, which aims at two or four high-precision measurements. A circular, 27 cm in diameter, BC-420 plastic-scintillator sheet is read-out by 32 photomultiplier tubes in order to achieve an intrinsic detector resolution on the order of 10 ps root mean square.

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

    Science.gov (United States)

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

    2016-08-01

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

  10. Dosimetry in clinical static magnetic fields using plastic scintillation detectors

    DEFF Research Database (Denmark)

    Stefanowicz, S.; Latzel, H.; Lindvold, Lars René

    2013-01-01

    . In conclusion, we found some deviations up to 7% of the supposed signal. Although the scintillators are of much denser material, we measured the same behavior in signal as in (Meijsing et al., 2009) for a Farmer ionization chamber or as in (Raaijmakers et al., 2007) for films described which indicates radiation...

  11. Measurements of the electron dose distribution near inhomogeneities using a plastic scintillation detector

    Energy Technology Data Exchange (ETDEWEB)

    Wells, C.M.M.; Mackie, T.R.; Podgorsak, M.B.; Holmes, M.A.; Papanikolaou, N.; Reckwerdt, P.J. [Univ. of Wisconsin, Madison, WI (United States); Cygler, J. [Ottawa Regional Cancer Center, Ontario (Canada); Rogers, D.W.O.; Bielajew, A.F. [National Research Council of Canada, Ottawa, Ontario (Canada); Schmidt, D.G. [Radiation Measurements, Inc., Middleton, WI (United States)] [and others

    1994-07-30

    Accurate measurement of the electron dose distribution near an inhomogeneity is difficult with traditional dosimeters which themselves perturb the electron field. The authors tested the performance of a new high resolution, water-equivalent plastic scintillation detector which has ideal properties for this application. A plastic scintillation detector with a 1 mm diameter, 3 mm long cylindrical sensitive volume was used to measure the dose distributions behind standard benchmark inhomogeneities in water phantoms. The plastic scintillator material is more water equivalent than polystyrene in terms of its mass collision stopping power and mass scattering power. Measurements were performed for beams of electrons having initial energies of 6 and 18 MeV at depths from 0.2-4.2 cm behind the inhomogeneities. The detector reveals hot and cold spots behind heterogeneities at resolutions equivalent to typical film digitizer spot sizes. Plots of the dose distributions behind air, aluminum, lead, and formulations for cortical and inner bone-equivalent materials are presented. The plastic scintillation detector is suited for measuring the electron dose distribution near an inhomogeneity. 14 refs., 9 figs.

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

    CERN Document Server

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

    2014-01-01

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

  13. Application of Compressive Sensing Theory for the Reconstruction of Signals in Plastic Scintillators

    CERN Document Server

    Raczyński, L; Bednarski, T; Białas, P; Czerwiński, E; Kapłon, Ł; Kochanowski, A; Korcyl, G; Kowal, J; Kozik, T; Krzemień, W; Molenda, M; Moskal, P; Niedźwiecki, Sz; Pałka, M; Pawlik, M; Rudy, Z; Salabura, P; Sharma, N G; Silarski, M; Słomski, A; Smyrski, J; Strzelecki, A; Wiślicki, W; Zieliński, M

    2013-01-01

    Compressive Sensing theory says that it is possible to reconstruct a measured signal if an enough sparse representation of this signal exists in comparison to the number of random measurements. This theory was applied to reconstruct signals from measurements of plastic scintillators. Sparse representation of obtained signals was found using SVD transform.

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

    Science.gov (United States)

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

    2011-11-01

    In this work Al2O3 and SiO2 coatings are tested as Xe diffusion barriers on plastic scintillator substrates. The motivation is improved beta-gamma coincidence detection systems, used to measure atmospheric radioxenon within the verification regime of the Comprehensive Nuclear-Test-Ban Treaty. One major drawback with the current setup of these systems is that the radioxenon tends to diffuse into the plastic scintillator material responsible for the beta detection, resulting in an unwanted memory effect. Here, coatings with thicknesses between 20 and 900 nm have been deposited onto plastic scintillators, and investigated using two different experimental techniques. The results show that all tested coatings reduce the Xe diffusion into the plastic. The reduction is observed to increase with coating thickness for both coating materials. The 425 nm Al2O3 coating is the most successful one, presenting a diffusion reduction of a factor 100, compared to uncoated plastic. In terms of memory effect reduction this coating is thus a viable solution to the problem in question.

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

    Energy Technology Data Exchange (ETDEWEB)

    Blaeckberg, L., E-mail: lisa.blackberg@physics.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Fay, A. [University of Texas at Austin, Nuclear Engineering Teaching Lab, J.J. Pickle Research Campus, R-9000 Austin, TX (United States); Jogi, I. [Department of Materials Chemistry, Uppsala University, Box 538, SE-75121 Uppsala (Sweden); Biegalski, S. [University of Texas at Austin, Nuclear Engineering Teaching Lab, J.J. Pickle Research Campus, R-9000 Austin, TX (United States); Boman, M. [Department of Materials Chemistry, Uppsala University, Box 538, SE-75121 Uppsala (Sweden); Elmgren, K.; Fritioff, T. [Division of Defence and Security Systems, Swedish Defence Research Agency (FOI), SE-17290 Stockholm (Sweden); Johansson, A. [Nanexa AB, Virdings Alle 32B, SE-75450 Uppsala (Sweden); Martensson, L.; Nielsen, F.; Ringbom, A. [Division of Defence and Security Systems, Swedish Defence Research Agency (FOI), SE-17290 Stockholm (Sweden); Rooth, M. [Nanexa AB, Virdings Alle 32B, SE-75450 Uppsala (Sweden); Sjoestrand, H.; Klintenberg, M. [Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

    2011-11-11

    In this work Al{sub 2}O{sub 3} and SiO{sub 2} coatings are tested as Xe diffusion barriers on plastic scintillator substrates. The motivation is improved beta-gamma coincidence detection systems, used to measure atmospheric radioxenon within the verification regime of the Comprehensive Nuclear-Test-Ban Treaty. One major drawback with the current setup of these systems is that the radioxenon tends to diffuse into the plastic scintillator material responsible for the beta detection, resulting in an unwanted memory effect. Here, coatings with thicknesses between 20 and 900 nm have been deposited onto plastic scintillators, and investigated using two different experimental techniques. The results show that all tested coatings reduce the Xe diffusion into the plastic. The reduction is observed to increase with coating thickness for both coating materials. The 425 nm Al{sub 2}O{sub 3} coating is the most successful one, presenting a diffusion reduction of a factor 100, compared to uncoated plastic. In terms of memory effect reduction this coating is thus a viable solution to the problem in question.

  16. Comparative analysis of pulse shape discrimination methods in a {sup 6}Li loaded plastic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Balmer, Matthew J.I., E-mail: m.balmer@lancaster.ac.uk [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Gamage, Kelum A.A. [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Taylor, Graeme C. [Neutron Metrology Group, National Physical Laboratory, Teddington, TW11 0LW (United Kingdom)

    2015-07-11

    Three algorithms for discriminating between fast neutrons, thermal neutrons and gamma rays in a {sup 6}Li loaded plastic scintillator have been compared. Following a literature review of existing pulse shape discrimination techniques, the performance of the charge comparison method, triangular filtering and frequency gradient analysis were investigated in this work. The scintillator was exposed to three different mixed gamma/neutron radiation fields. The figure of merit of neutron/gamma separation was investigated over a broad energy range, as well as for the neutron capture energy region. After optimisation, all three methods were found to perform similarly in terms of neutron/gamma separation.

  17. Coincidence system for standardization of radionuclides using a 4pi plastic scintillator detector.

    Science.gov (United States)

    Baccarelli, Aída M; Dias, Mauro S; Koskinas, Marina F

    2003-02-01

    A coincidence system using a plastic scintillator detector in 4pi geometry has been developed and applied for the standardization of radionuclides. The scintillator shape and dimensions have been optimized for maximum charge particle detection efficiency, while keeping background low and a nearly constant gamma-ray efficiency for different points from the radioactive source. The gamma-ray events were measured with a NaI(Tl) scintillation counter. The electronic system for processing pulses consisted of logic gates and delay modules feeding a time-to-amplitude converter with output to a multichannel analyzer. The alpha detection efficiency measured with 241Am was around 95% and the beta detection efficiency for 60Co was around 67%. Activity measurements of 241Am and 60Co were performed and the results showed good agreement when compared with a conventional coincidence system employing a 4pi proportional counter.

  18. Coincidence system for standardization of radionuclides using a 4 pi plastic scintillator detector

    CERN Document Server

    Baccarelli, A M; Koskinas, M F

    2003-01-01

    A coincidence system using a plastic scintillator detector in 4 pi geometry has been developed and applied for the standardization of radionuclides. The scintillator shape and dimensions have been optimized for maximum charge particle detection efficiency, while keeping background low and a nearly constant gamma-ray efficiency for different points from the radioactive source. The gamma-ray events were measured with a NaI(Tl) scintillation counter. The electronic system for processing pulses consisted of logic gates and delay modules feeding a time-to-amplitude converter with output to a multichannel analyzer. The alpha detection efficiency measured with sup 2 sup 4 sup 1 Am was around 95% and the beta detection efficiency for sup 6 sup 0 Co was around 67%. Activity measurements of sup 2 sup 4 sup 1 Am and sup 6 sup 0 Co were performed and the results showed good agreement when compared with a conventional coincidence system employing a 4 pi proportional counter.

  19. Quenching Factor for Low Energy Nuclear Recoils in a Plastic Scintillator

    CERN Document Server

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

    2011-01-01

    Plastic scintillators are widely used in industry, medicine and scientific research, including nuclear and particle physics. Although one of their most common applications is in neutron detection, experimental data on their response to low-energy nuclear recoils are scarce. Here, the relative scintillation efficiency for neutron-induced nuclear recoils in a polystyrene-based plastic scintillator (UPS-923A) is presented, exploring recoil energies between 125 keV and 850 keV. Monte Carlo simulations, incorporating light collection efficiency and energy resolution effects, are used to generate neutron scattering spectra which are matched to observed distributions of scintillation signals to parameterise the energy-dependent quenching factor. At energies above 300 keV the dependence is reasonably described using the semi-empirical formulation of Birks and a kB factor of (0.014+/-0.002) g/MeVcm^2 has been determined. Below that energy the measured quenching factor falls more steeply than predicted by the Birks for...

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

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan, E-mail: jonathan.dumazert@cea.fr [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Coulon, Romain; Bertrand, Guillaume H.V.; Normand, Stéphane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Méchin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 14050 Caen (France); Hamel, Matthieu [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France)

    2016-05-21

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

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

    Science.gov (United States)

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

    2016-05-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

  4. Determination of spatial resolution of plastic scintillation fiber array with a simple method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The spatial resolution of a position sensitive gamma-ray detector configuration based on plastic scintillation fiber array was measured using a Monte Carlo simulation method. Both point spread function and modulation transfer function (MTF) were presented. The factors that influence the spatial resolution were also discussed. The results of the simulation showed that the intrinsic spatial resolution was consistent with the size of the physical pixels and a few centimeters spatial resolution could be obtained under certain circumstances.

  5. Three dimensional photograph of electron tracks through a plastic scintillator

    CERN Document Server

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

    2014-01-01

    The reconstruction of particle trajectories makes it possible to distinguish between different types of charged particles. In the era of particle colliders and high luminosities, this was one of the key aspects for the discovery of many new particles, lately the Higgs-boson. In high-energy physics, where trajectories are rather long. large size trackers muste be used to achieve sufficient position resolution. This is not the case in low-energy particle physics experiments, where particle trajectories are very short. With current position-sensitive detection technologies it is difficult to obtain sufficient position resolution for particle identification in large sensitive volumes since all these detectors are based on the read-out of the ionization signal. This limitation is due to the diffusion of the drifting electrons. In this paper we demonstrate a "proof-of-principle" experiment for a new method for the tracking of charged particles. It takes advantage of the scintillation signal which is not affected by...

  6. Test of a single module of the J-PET scanner based on plastic scintillators

    CERN Document Server

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

    2014-01-01

    Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this article we report on tests of a single detection module built out from BC-420 plastic scintillator strip (with dimensions of 5x19x300mm^3) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50ps intervals. The time resolution of the prototype module was established to be better than 80ps (sigma) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93cm (sigma) for the annihilation quanta...

  7. Comparison of Lithium Gadolinium Borate Crystal Shards in Scintillating and Nonscintillating Plastic Matrices

    CERN Document Server

    Kazkaz, Kareem; Pedretti, Marisa

    2011-01-01

    We present a method for detecting neutrons using scintillating lithium gadolinium borate crystal shards in a plastic matrix while maintaining high gamma rejection. We have procured two cylindrical detectors, 5"\\times5", containing 1% crystal by mass. Crystal shards have a typical dimension of 1 mm. One detector was made with scintillating plastic, and one with nonscintillating plastic. Pulse shape analysis was used to reject gamma ray backgrounds. The scintillating detector was measured to have an intrinsic fast fission neutron efficiency of 0.4% and a gamma sensitivity of less than 2.3 \\times 10-9, while the nonscintillating detector had a neutron efficiency of 0.7% and gamma sensitivity of (4.75\\pm3.94)\\times10-9. We determine that increasing the neutron detection efficiency by a factor of 2 will make the detector competitive with moderated 3He tubes, and we discuss several simple and straightforward methods for obtaining or surpassing such an improvement. We end with a discussion of possible applications, ...

  8. Digital Gamma-Neutron Discrimination with Organic Plastic Scintillator EJ 299-33

    Directory of Open Access Journals (Sweden)

    Nyibule S.

    2014-07-01

    Full Text Available The neutron / gamma pulse shape discrimination (PSD is measured for the newly dis- covered plastic scintillator EJ 299-33 using a fast digitizer DDC10. This plastic scin- tillator (EJ 299-33 discovered by Lawrence Livermore National Laboratory(LLNL is now commercially available by Eljen Technology. Some of its properties include light output emission efficiency of 56 / 100 (of Anthracene, wavelength of maximum emis- sion of 420 nm, C:H ratio of 1:1.06 and density of 1.08 g / cm 3 . The PSD between neutrons and gamma rays in this plastic scintillator is studied using a 5.08-cm diameter by 5.08-cm thick sample irradiated by a neutron-gamma source AmBe-241 and em- ploying charge integration method. The results show that EJ 299-33 has a very good PSD, having a figure of merit of approximately 0.80, 2.5 and 3.09 at 100 KeVee, 450 KeVee and 750 KeVee light outputs respectively. The performance of this new material is compared to that of a liquid scintillator with a well proven excellent PSD performance NE213, having a figure of merit of 0.93, 2.95 and 3.30 at 100 KeVee, 450 KeVee and 750 KeVee respectively. The PSD performance of EJ 299-33 is found to be comparable to that of NE 213.

  9. Compensated gadolinium-loaded plastic scintillators for thermal neutron detection (and counting)

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan; Coulon, Romain; Bertrand, Guillaume H. V.; Hamel, Matthieu; Sguerra, Fabien; Dehe-Pittance, Chrystele; Normand, Stephane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 99 Gif-sur-Yvette, (France); Mechin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 4050 Caen, (France)

    2015-07-01

    Plastic scintillator loading with gadolinium-rich organometallic complexes shows a high potential for the deployment of efficient and cost-effective neutron detectors. Due to the low-energy photon and electron signature of thermal neutron capture by gadolinium-155 and gadolinium-157, alternative treatment to Pulse Shape Discrimination has to be proposed in order to display a trustable count rate. This paper discloses the principle of a compensation method applied to a two-scintillator system: a detection scintillator interacts with photon radiation and is loaded with gadolinium organometallic compound to become a thermal neutron absorber, while a non-gadolinium loaded compensation scintillator solely interacts with the photon part of the incident radiation. Posterior to the nonlinear smoothing of the counting signals, a hypothesis test determines whether the resulting count rate after photon response compensation falls into statistical fluctuations or provides a robust image of a neutron activity. A laboratory prototype is tested under both photon and neutron irradiations, allowing us to investigate the performance of the overall compensation system in terms of neutron detection, especially with regards to a commercial helium-3 counter. The study reveals satisfactory results in terms of sensitivity and orientates future investigation toward promising axes. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, Pauline [CEA, LIST, Laboratoire Capteurs et Architectures Électroniques, F-91191 Gif-sur-Yvette (France); Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (CNRS UMR 8531), École Normale Supérieure de Cachan, 61 Avenue du Président Wilson, F-94235 Cachan cedex (France); Hamel, Matthieu, E-mail: matthieu.hamel@cea.fr [CEA, LIST, Laboratoire Capteurs et Architectures Électroniques, F-91191 Gif-sur-Yvette (France); Dehé-Pittance, Chrystèle; Rocha, Licinio [CEA, LIST, Laboratoire Capteurs et Architectures Électroniques, F-91191 Gif-sur-Yvette (France); Pansu, Robert B. [Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (CNRS UMR 8531), École Normale Supérieure de Cachan, 61 Avenue du Président Wilson, F-94235 Cachan cedex (France); Normand, Stéphane [CEA, LIST, Laboratoire Capteurs et Architectures Électroniques, F-91191 Gif-sur-Yvette (France)

    2014-06-01

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

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

    CERN Document Server

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

    2016-01-01

    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2 x...

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

    Energy Technology Data Exchange (ETDEWEB)

    Ifergan, Y., E-mail: Yairifergan@gmail.com [Electronics & Control Laboratories, Nuclear Research Center Negev, PO Box 9001, Beer Sheva (Israel); Dadon, S. [Electronics & Control Laboratories, Nuclear Research Center Negev, PO Box 9001, Beer Sheva (Israel); Israelashvili, I. [Physics Department, Nuclear Research Center of the Negev, PO Box 9001, Beer Sheva (Israel); Osovizky, A. [Radiation Detection Department, Rotem Industries Ltd, Beer Sheva (Israel); Gonen, E.; Yehuda-Zada, Y.; Smadja, D. [Electronics & Control Laboratories, Nuclear Research Center Negev, PO Box 9001, Beer Sheva (Israel); Knafo, Y.; Ginzburg, D. [Radiation Detection Department, Rotem Industries Ltd, Beer Sheva (Israel); Kadmon, Y.; Cohen, Y.; Mazor, T. [Electronics & Control Laboratories, Nuclear Research Center Negev, PO Box 9001, Beer Sheva (Israel)

    2015-06-01

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

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

    CERN Document Server

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

    2015-01-01

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

  14. Image quality evaluation of linear plastic scintillating fiber array detector for X-ray imaging

    Institute of Scientific and Technical Information of China (English)

    Mohammad Mehdi NASSERI; MA Qing-Li; YIN Ze-Jie

    2004-01-01

    It is important to assess image quality, in order to ensure that the imaging system is performing optimally and also identify the weak points in an imaging system. Three parameters mostly leading to image degradation are contrast, spatial resolution and noise. There is always a trade-off between spatial resolution and signal to noise ratio,but in scintillating fiber array detectors spatial resolution is not as important as signal to noise ratio, so we paid more attention to contrast and SNR of the system. By using GEANT4 Monte Carlo detector simulation toolkit, some effective parameters of the linear plastic scintillating fiber (PSF) array as an imaging detector were investigated. Finally we show that it is possible to use this kind of detector to take CT and DR (Digital Radiography) image under certain conditions.

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Méchin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 14050 Caen (France); Hamel, Matthieu [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France)

    2016-08-21

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

  18. Enhanced light extraction efficiency of plastic scintillator by photonic crystal prepared with a self-assembly method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jinliang [State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Radiation Detection Research Center, Northwest Institute of Nuclear Technology, Xi’an, 710024 (China); Zhu, Zhichao [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Chen, Liang; Ouyang, Xiaoping [State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Radiation Detection Research Center, Northwest Institute of Nuclear Technology, Xi’an, 710024 (China); Liu, Bo, E-mail: lbo@tongji.edu.cn [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Cheng, Chuanwei [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Hu, Jing; He, Shiyi [State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Radiation Detection Research Center, Northwest Institute of Nuclear Technology, Xi’an, 710024 (China); Wang, Zewei [State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Radiation Detection Research Center, Northwest Institute of Nuclear Technology, Xi’an, 710024 (China); College of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Gu, Mu; Chen, Hong [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China)

    2015-09-21

    Plastic scintillators are extensively used in various radiation measurement systems. However the total internal reflection decreases the scintillation light output, leading to a low detection efficiency especially in these weak signal detection situations. In the present investigation, we have designed a light extraction scheme based on the photonic crystal formed with a monolayer periodic array of polystyrene nanospheres by a self-assembly method. The photonic crystal coated on the surface of plastic scintillator can significantly enhance the light extraction by 120% compared with the plain reference sample under X-ray excitation, which is achieved by the principle of the coupling of evanescent field near the scintillator-air interface with the photonic crystal.

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

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, J; Beaulieu, L [University Laval, Quebec, QC (Canada); Centre Hospitalier University de Quebec, Quebec, QC (Canada); Beddar, S [University of Texas MD Anderson Cancer Center, Houston, TX (United States); Guillemette, M [Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Quebec, QC (Canada)

    2014-06-15

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

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

    Science.gov (United States)

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

    2008-01-01

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

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

    Science.gov (United States)

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

    2016-08-01

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

  2. Monte-Carlo simulation for determining SNR and DQE of linear array plastic scintillating fiber

    Institute of Scientific and Technical Information of China (English)

    Mohammad Mehdi NASSERI; MA Qing-Li; YIN Ze-Jie; WU Xiao-Yi

    2004-01-01

    Fundamental characteristics of the plastic-scintillating fiber (PSF) for wide energy range of electromagnetic radiation (X & γ) have been studied to evaluate possibility of using the PSF as an imaging detector for industrial purposes. Monte-Carlo simulation program (GEANT4.5.1, 2003) was used to generate the data. In order to evaluate image quality of the detector, fiber array was irradiated under various energy and fluxes. Signal to noise ratio (SNR)as well as detector quantum efficiency (DQE) were obtained.

  3. Extensive studies of MRS APDs for plastic scintillator muon veto detectors of cryogenic experiments

    Energy Technology Data Exchange (ETDEWEB)

    Falkenstein, R., E-mail: falkenst@pit.physik.uni-tuebingen.de [Kepler Center for Astro and Particle Physics, University of Tuebingen, Auf der Morgenstelle 14, 72076 Tuebingen (Germany); Bezrukov, L.B. [Institute for Nuclear Research of RAS, Moscow (Russian Federation); Freund, K. [Kepler Center for Astro and Particle Physics, University of Tuebingen, Auf der Morgenstelle 14, 72076 Tuebingen (Germany); Golovin, A.V.; Golovin, V.M. [Centre for Perspective Technology and Apparatus, Moscow (Russian Federation); Grabmayr, P.; Jochum, J. [Kepler Center for Astro and Particle Physics, University of Tuebingen, Auf der Morgenstelle 14, 72076 Tuebingen (Germany); Lubsandorzhiev, B.K. [Kepler Center for Astro and Particle Physics, University of Tuebingen, Auf der Morgenstelle 14, 72076 Tuebingen (Germany); Institute for Nuclear Research of RAS, Moscow (Russian Federation); Lubsandorzhiev, N.B.; Poleshuk, R.V. [Institute for Nuclear Research of RAS, Moscow (Russian Federation); Polyansky, I.N. [Centre for Perspective Technology and Apparatus, Moscow (Russian Federation); Ritter, F.; Sailer, C. [Kepler Center for Astro and Particle Physics, University of Tuebingen, Auf der Morgenstelle 14, 72076 Tuebingen (Germany); Shaibonov, B.A.M. [Institute for Nuclear Research of RAS, Moscow (Russian Federation)

    2012-12-11

    Low background experiments need active muon veto detectors to shield them from cosmic muons. Plastic scintillator panels with WLS fiber and multi-pixel Geiger-mode avalanche photodiodes readout are widely used in such experiments due to their compactness and robustness. In this paper, results from the study of the basic MRS APD parameters, such as breakdown voltages, quenching resistors, internal gain and dark count rates are presented, as well as temperature dependencies of some of these parameters. In a small fraction of the MRS APDs, some strange dips in the I-V curves just preceding the breakdown voltage point have been observed.

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

    DEFF Research Database (Denmark)

    Ottosson, Wiviann; Behrens, C. F.; Andersen, Claus E.

    2015-01-01

    Bone, air passages, cavities, and lung are elements present in patients, but challenging to properly correct for in treatment planning dose calculations. Plastic scintillator detectors (PSDs) have proven to be well suited for dosimetry in non-reference conditions such as small fields. The objective...... of this study was to investigate the performance of a commercial treatment planning system (TPS) using a PSD and a specially designed thorax phantom with lung tumor inserts. 10 treatment plans of different complexity and phantom configurations were evaluated. Although the TPS agreed well with the measurements...

  5. Two-dimensional X-ray imaging using plastic scintillating fiber array

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Due to its low cost,flexibility and convenience for long distance dala transfer,plastic scintillation fiber (PSF)have been increasingly used in building detectors or sensors for detecting various radiations and imaging.In this work,the performance of using PSF coupled with charge-coupled devices(CCD)to build are adetectors for 2D X-ray imaging is studied.We describe the experimental setup and show the obtained images from CCD.Modulation Transfer Function(MTF)of the PSF array is also presented and compared to earlier reports.

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

    Science.gov (United States)

    Richardson, Norman E., IV

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

  7. Neutron irradiation and damage assessment of plastic scintillators of the Tile Calorimeter

    Science.gov (United States)

    Mdhluli, J. E.; Mellado, B.; Sideras-Haddad, E.

    2017-01-01

    Following the comparative study of proton induced radiation damage on various plastic scintillator samples from the ATLAS-CERN detector, a study on neutron irradiation and damage assessment on the same type of samples will be conducted. The samples will be irradiated with different dose rates of neutrons produced in favourable nuclear reactions using a radiofrequency linear particle accelerator as well as from the SAFARI nuclear reactor at NECSA. The MCNP 5 code will be utilized in simulating the neutron transport for determining the dose rate. Light transmission and light yield tests will be performed in order to assess the radiation damage on the scintillators. In addition, Raman spectroscopy and Electron Paramagnetic Resonance (EPR) analysis will be used to characterize the samples after irradiation. The project aims to extent these studies to include radiation assessment damage of any component that processes the scintillating light and deteriorates the quantum efficiency of the Tilecal detector, namely, photomultiplier tubes, wavelength shifting optical fibres and the readout electronics. They will also be exposed to neutron irradiation and the damage assessed in the same manner.

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

    Science.gov (United States)

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

    2015-05-11

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

  9. Control Modules for Scintillation Counters in the SPS Experimental Areas

    CERN Document Server

    Baribaud, Guy; Cojan, A; Ferri, G; Fullerton, J; Manarin, A; Spanggaard, J

    2001-01-01

    The hardware used in the SPS Experimental Areas to control the beam instrumentation electronics and mechanics of the particle detectors is based on CAMAC and NIM modules. The maintenance of this hardware now presents very serious problems. The modules used to operate the Experimental Areas are numerous and older than 20 years so many of them cannot be repaired any more and CAMAC is no longer well supported by industry. The fast evolution of technology and a better understanding of the detectors allow a new equipment-oriented approach, which is more favourable for maintenance purposes and presents fewer data handling problems. VME and IP Modules were selected as standard components to implement the new electronics to control and read out the particle detectors. The first application implemented in this way concerns the instrumentation for the Scintillation Counters (formerly referred to as triggers). The fundamental options and the design features will be presented.

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

    Science.gov (United States)

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

    2013-07-01

    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.

  11. Plastic scintillation detectors for precision time-of-flight measurements of relativistic heavy ions

    CERN Document Server

    Lin, Wen-Jian; Sun, Bao-Hua; He, Liu-Chun; Lin, Wei-Ping; Liu, Chuan-Ye; Tanihata, Isao; Terashima, Satoru; Tian, Yi; Wang, Feng; Wang, Meng; Zhang, Guang-Xin; Zhang, Xue-Heng; Zhu, Li-Hua; Duan, Li-Min; Hu, Rong-Jiang; Liu, Zhong; Lu, Chen-Gui; Ren, Pei-Pei; Sheng, Li-Na; Sun, Zhi-Yu; Wang, Shi-Tao; Wang, Tao-Feng; Xu, Zhi-Guo; Yan, Duo; Yue, Ke; Zheng, Yong

    2016-01-01

    Plastic scintillation detectors for Time-of-Flight (TOF) measurements are almost essential for event-by-event identification of relativistic rare isotopes. In this work, a pair of plastic scintillation detectors of 50 $\\times$ 50 $\\times$ 3$^{t}$ mm$^3$ and 80 $\\times$ 100 $\\times$ 3$^{t}$ mm$^3$ have been set up at the external target facility (ETF), Institute of Modern Physics. Their time, energy and position responses are measured with $^{18}$O primary beam at 400 MeV/nucleon. After the off-line walk-effect and position corrections, the time resolution of the two detectors are determined to be 27 ps ($\\sigma$) and 36 ps ($\\sigma$), respectively. Both detectors have nearly the same energy resolution of 3$\\%$ ($\\sigma$) and position resolution of 2 mm ($\\sigma$). The detectors have been used successfully in nuclear reaction cross section measurements, and will be be employed for upgrading RIBLL2 beam line at IMP as well as for the high energy branch at HIAF.

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2014-10-08

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

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

    Science.gov (United States)

    Liao, Can; Yang, Haori

    2015-07-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

  16. Plastic scintillators utilization in position sensitive detection systems; Uitilizacao de cintiladores plasticos em sistemas de deteccao sensiveis a posicao

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Marcelo Bernardes; Soares, Adalberto Jose; Baptista Filho, Benedito Dias [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2002-07-01

    This paper shows the viability of using a plastic scintillator detector to determine the one dimension position of a radioactive source. The experiments were performed using collimated {sup 99m} Tc sources of several activities supplied by the Centro de Radiofarmacia (from IPEN), and a 15 cm long plastic scintillator with diameter 5,08 cm, produced by the Centro de Tecnologia das Radiacoes (also from IPEN). The spectrum was obtained using the Genie 2000 software, and the results processed using a neural network specially developed for the proposed application. The final results demonstrate the viability of the proposed application. (author)

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Consolati, G. [Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa 34, 20156 Milano (Italy); Franco, D., E-mail: dfranco@in2p3.fr [APC, Univ. Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs. de Paris, Sorbonne Paris Cité, 75205 Paris (France); Jollet, C. [IPHC, Université de Strasbourg, CNRS/IN2P3, 67037 Strasbourg (France); Meregaglia, A., E-mail: amerega@in2p3.fr [IPHC, Université de Strasbourg, CNRS/IN2P3, 67037 Strasbourg (France); Minotti, A. [IPHC, Université de Strasbourg, CNRS/IN2P3, 67037 Strasbourg (France); Perasso, S.; Tonazzo, A. [APC, Univ. Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs. de Paris, Sorbonne Paris Cité, 75205 Paris (France)

    2015-09-21

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

  20. Compressive Sensing of Signals Generated in Plastic Scintillators in a Novel J-PET Instrument

    CERN Document Server

    Raczynski, L; Kowalski, P; Wislicki, W; Bednarski, T; Bialas, P; Czerwinski, E; Gajos, A; Kaplon, L; Kochanowski, A; Korcyl, G; Kowal, J; Kozik, T; Krzemien, W; Kubicz, E; Niedzwiecki, Sz; Palka, M; Rudy, Z; Rundel, O; Salabura, P; Sharma, N G; Silarski, M; lomski, A S; Smyrski, J; Strzelecki, A; Wieczorek, A; Zielinski, M; Zon, N

    2015-01-01

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

  1. High-pressure plastic scintillation detector for measuring radiogenic gases in flow systems

    CERN Document Server

    Schell, W R; Yoon, S R; Tobin, M J

    1999-01-01

    Radioactive gases are emitted into the atmosphere from nuclear electric power and nuclear fuel reprocessing plants, from hospitals discarding xenon used in diagnostic medicine, as well as from nuclear weapons tests. A high-pressure plastic scintillation detector was constructed to measure atmospheric levels of such radioactive gases by detecting the beta and internal conversion (IC) electron decays. Operational tests and calibrations were made that permit integration of the flow detectors into a portable Gas Analysis, Separation and Purification system (GASP). The equipment developed can be used for measuring fission gases released from nuclear reactor sources and/or as part of monitoring equipment for enforcing the Comprehensive Test Ban Treaty. The detector is being used routinely for in-line gas separation efficiency measurements, at the elevated operational pressures used for the high-pressure swing analysis system (2070 kPa) and at flow rates of 5-15 l/min . This paper presents the design features, opera...

  2. 2-(2{prime}-hydroxyphenyl)benzothiazoles, -benzoxazoles, and -benzimidazoles for plastic scintillation applications

    Energy Technology Data Exchange (ETDEWEB)

    Pla-Dalmau, A. [Fermi National Accelerator Lab., Batavia, IL (United States)

    1995-08-25

    A new series of fluorescent compounds has been tested as dopants for plastic scintillation applications. Several 2-(2{prime}-hydroxyphenyl)benzothiazole, -benzoxazole, and -benzimidazole derivatives have been prepared and studied in a polystyrene matrix. Each derivative has been added to a styrene solution which has been thermally polymerized. The transmittance, fluorescence, and light yield characteristics of these compounds in polystyrene have been determined. Their emission time distributions have also been measured, and the decay time constants have been calculated from these data. In addition, the doped polystyrene samples have been irradiated to a total dose of 10 Mrad, utilizing a {sup 60}Co source in order to evaluate their susceptibility to radiation-induced damage. 6 figs., 1 tab.

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kaminska, D.; Gajos, A.; Czerwinski, E.; Alfs, D.; Bednarski, T.; Bialas, P.; Dulski, K.; Glowacz, B.; Gupta-Sharma, N.; Korcyl, G.; Krawczyk, N.; Kubicz, E.; Mohammed, M.; Niedzwiecki, Sz.; Pawlik-Niedzwiecka, M.; Rudy, Z.; Wieczorek, A.; Zielinski, M.; Moskal, P. [Jagiellonian University, Faculty of Physics, Astronomy and Applied Computer Science, Krakow (Poland); Curceanu, C.; Silarski, M. [INFN, Laboratori Nazionali di Frascati, CP 13, Frascati (Italy); Gorgol, M.; Jasinska, B.; Zgardzinska, B. [Maria Curie-Sklodowska University, Department of Nuclear Methods, Institute of Physics, Lublin (Poland); Hiesmayr, B.C. [University of Vienna, Faculty of Physics, Vienna (Austria); Kowalski, P.; Raczynski, L.; Wislicki, W. [Swierk Computing Centre, National Centre for Nuclear Research, Otwock-Swierk (Poland); Krzemien, W. [National Centre for Nuclear Research, High Energy Department, Otwock-Swierk (Poland)

    2016-08-15

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

  5. Spatial distributions of photons in plastic scintillator detected by multi-anode photomultiplier for heavy-ion position determination

    Energy Technology Data Exchange (ETDEWEB)

    Omika, S. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Yamaguchi, T., E-mail: yamaguti@phy.saitama-u.ac.jp [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Fukuda, M. [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Kitagawa, A. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Matsunaga, S. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Nagae, D. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Nishimura, D. [Department of Physics, Tokyo University of Science, Noda 278-8510 (Japan); Nishimura, T. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Ozawa, A. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Sato, S. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Sawahata, K. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Suzuki, T.; Takeuchi, Y. [Department of Physics, Saitama University, Saitama 338-8570 (Japan)

    2015-10-11

    The spatial distributions of scintillation photons in a plastic scintillation detector were measured using a multi-anode photomultiplier H7546A coupled with 1-mm-diameter optical fibers. A row of several tens of fibers connected to the scintillator generates one-dimensional spatial distributions of photons induced by the swift passage of heavy ions. The pulse heights from each channel change depending on the beam position. This can be utilized to determine the positions of the heavy ions. To test the performance of the proposed detection method, an experiment using a {sup 84}Kr beam with intermediate energies ranging from 40 to 85 MeV/nucleon was performed at the heavy-ion medical accelerator in Chiba (HIMAC). The photon spatial distributions were successfully observed. By optimizing the photomultiplier bias voltage and threshold in the pulse height analyses, a detection efficiency of 98% and a position resolution of 1.1 mm in σ were achieved simultaneously.

  6. Properties of the Ukrainian Polystyrene-Based Plastic Scintillator UPS 923A

    CERN Document Server

    Artikov, A M; Chirikov-Zorin, I E; Chokheli, D; Lyablin, M; Bellettini, G; Menzione, A; Tokar, S; Giokaris, N; Manousakis-Katsikakis, A

    2005-01-01

    The polystyrene-based scintillator UPS 923A was chosen for upgrading of the muon system for the CDF detector at the Fermilab Tevatron. Properties of this scintillator such as light output, light attenuation, long-term stability and also timing characteristics of scintillator and wavelength shifting fibers were investigated. The method for the Bulk Attenuation Length measurements of the scintillator to its own light emitted was proposed. Comparative measurements of the characteristics of the UPS 923A and the polyvinyltoluene-based scintillator NE 114 were performed. It was found that natural aging of the NE 114 was two times faster than that of the UPS 923A.

  7. Plutonium metal vs. oxide determination with the pulse-shape-discrimination-capable plastic scintillator EJ-299-33

    Energy Technology Data Exchange (ETDEWEB)

    Pozzi, S.A., E-mail: pozzisa@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Bourne, M.M.; Dolan, J.L.; Polack, K.; Lawrence, C.; Flaska, M.; Clarke, S.D. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Tomanin, A.; Peerani, P. [European Commission Joint Research Centre, Institute for the Protection and Security of the Citizen Via Enrico Fermi, 2749 21027 Ispra VA (Italy)

    2014-12-11

    Neutron measurements can be used to distinguish plutonium in metal or oxide form, a capability that is of great interest in nuclear nonproliferation, treaty verification, and other applications. This paper describes measurements performed on well-characterized samples of plutonium oxide and plutonium metal using the pulse-shape-discrimination-capable plastic scintillator EJ-299-33. Results are compared to those obtained with a same-sized detector cell using the liquid scintillator EJ-309. The same optimized, digital pulse shape discrimination technique is applied to both detectors and the neutron pulse height distributions are compared. Results show that the EJ-299-33 plastics can be successfully used for plutonium measurements, where the gamma ray to neutron detection ratio is much higher than for typical radioactive sources. Results also show that EJ-299-33 detectors can be used to characterize plutonium samples, specifically to discriminate between plutonium metal and oxide.

  8. Memory effect, resolution, and efficiency measurements of an Al2O3 coated plastic scintillator used for radioxenon detection

    Science.gov (United States)

    Bläckberg, L.; Fritioff, T.; Mårtensson, L.; Nielsen, F.; Ringbom, A.; Sjöstrand, H.; Klintenberg, M.

    2013-06-01

    A cylindrical plastic scintillator cell, used for radioxenon monitoring within the verification regime of the Comprehensive Nuclear-Test-Ban Treaty, has been coated with 425 nm Al2O3 using low temperature Atomic Layer Deposition, and its performance has been evaluated. The motivation is to reduce the memory effect caused by radioxenon diffusing into the plastic scintillator material during measurements, resulting in an elevated detection limit. Measurements with the coated detector show both energy resolution and efficiency comparable to uncoated detectors, and a memory effect reduction of a factor of 1000. Provided that the quality of the detector is maintained for a longer period of time, Al2O3 coatings are believed to be a viable solution to the memory effect problem in question.

  9. Pulse shape discrimination between (fast or thermal) neutrons and gamma rays with plastic scintillators: State of the art

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, Guillaume H.V. [CEA, LIST, Laboratoire Capteurs & Architectures Électroniques, CEA Saclay, F-91191 Gif-sur-Yvette cedex (France); Hamel, Matthieu, E-mail: matthieu.hamel@cea.fr [CEA, LIST, Laboratoire Capteurs & Architectures Électroniques, CEA Saclay, F-91191 Gif-sur-Yvette cedex (France); Normand, Stéphane [CEA, DAM, Le Ponant, 25 rue Leblanc, F-75015 Paris (France); Sguerra, Fabien [CEA, LIST, Laboratoire Capteurs & Architectures Électroniques, CEA Saclay, F-91191 Gif-sur-Yvette cedex (France)

    2015-03-11

    We would like to present here with the eyes of the chemist the most recent developments of plastic scintillators (PS) for neutron detection. This review covers the period from 2000 to August 2014, and is fragmented in two main chapters. The first chapter deals with the chemical modifications for thermal neutron capture, whereas the second chapter presents the various strategies used to enhance the response to fast neutrons via pulse shape discrimination. For each chapter the theory is also explained.

  10. GEANT4 simulation of plastic scintillator strips with embedded optical fibers for a prototype of tomographic system

    Energy Technology Data Exchange (ETDEWEB)

    Riggi, S., E-mail: simone.riggi@ct.infn.i [Department of Physics and Astronomy, University of Catania (Italy); INFN Section of Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia (Italy); La Rocca, P. [Department of Physics and Astronomy, University of Catania (Italy); INFN Section of Catania (Italy); Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' , Roma (Italy); Leonora, E.; Lo Presti, D. [Department of Physics and Astronomy, University of Catania (Italy); INFN Section of Catania (Italy); Pappalardo, G.S. [INFN Section of Catania (Italy); Riggi, F.; Russo, G.V. [Department of Physics and Astronomy, University of Catania (Italy); INFN Section of Catania (Italy)

    2010-12-21

    The response to cosmic muons of plastic scintillator strips, with and without wavelength shifter fibers embedded, read out at both edges by photomultipliers has been studied through detailed GEANT4 simulations, with the aim of studying the light collection at the module ends under different conditions. The performed simulations, validated and tuned with data coming from a module prototype, could serve as an important guide for the design of a tomographic system based on cosmic ray muons.

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

    CERN Document Server

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

    2014-01-01

    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 threshold...

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

    Energy Technology Data Exchange (ETDEWEB)

    Raczyński, L., E-mail: lech.raczynski@ncbj.gov.pl [Świerk Computing Centre, National Centre for Nuclear Research, 05-400 Otwock-Świerk (Poland); Moskal, P. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-059 Cracow (Poland); Kowalski, P.; Wiślicki, W. [Świerk Computing Centre, National Centre for Nuclear Research, 05-400 Otwock-Świerk (Poland); Bednarski, T.; Białas, P.; Czerwiński, E.; Gajos, A. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-059 Cracow (Poland); Kapłon, Ł. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-059 Cracow (Poland); Institute of Metallurgy and Materials Science of Polish Academy of Sciences, Cracow (Poland); Kochanowski, A. [Faculty of Chemistry, Jagiellonian University, 30-060 Cracow (Poland); Korcyl, G.; Kowal, J.; Kozik, T.; Krzemień, W.; Kubicz, E.; Niedźwiecki, Sz.; Pałka, M.; Rudy, Z.; Rundel, O.; Salabura, P. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-059 Cracow (Poland); and others

    2015-06-21

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

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

    Science.gov (United States)

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

    2016-08-01

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

  14. Timing tests of silicon-photomultipliers for readout of large plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Gohl, Stefan; Cowan, Thomas E.; Roeder, Marko [Helmholtz-Zentrum Dresden-Rossendorf (HZDR) (Germany); TU Dresden (Germany); Bemmerer, Daniel; Heidel, Klaus; Stach, Daniel; Wagner, Andreas; Weinberger, David [Helmholtz-Zentrum Dresden-Rossendorf (HZDR) (Germany); Reinhardt, Tobias [TU Dresden (Germany); Helmholtz-Zentrum Dresden-Rossendorf (HZDR) (Germany); Collaboration: R3B-Collaboration

    2014-07-01

    Silicon Photomultipliers (SiPMs) are under study as a possible replacement for timing photomultiplier tubes (PMTs) in the NeuLAND (New Large Area Neutron Detector) detector at FAIR. SiPMs have several advantages over PMTs. They are insensitive to magnetic fields, small and they can be manufactured economically. Therefore, studies have been made with different SiPMs, preamplifiers and scintillators aiming to find a suitable setup with a good timing resolution for NeuLAND. Some parameters, e.g. bias voltage and light input, were tuned as well. The SiPMs were irradiated with an electron beam at ELBE and a picosecond laser system while the signals were recorded with a digital oscilloscope and evaluated by using a software Constant Fraction Discriminator (CFD). Preliminary results are presented.

  15. DETEC, a Subprogram for Simulation of the Fast-Neutron Detection Process in a Hydro-Carbonous Plastic Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, B.; Aspelund, O.

    1966-07-15

    A description is given of the subprogram DETEC, which for energies below 5 MeV simulates the detection process of a fast-neutron within a large cylindrical plastic scintillator. DETEC has been coded in FORTRAN IV, and consists of a subroutine and a BLOCK-DATA subprogram. The latter is in its present form adapted to the dimensions 5 cm diam. x 8 cm of the scintillating materials NE102 and NE102A. The character of DETEC as a subprogram is manifest through the requirement of a main routine for generation of the following input parameters: 1. fast-neutron position; 2. direction; 3. energy; 4. entrance time; 5. input weight (all referred to the detector surface), and 6. the discriminator threshold. When these are provided, the virtues of DETEC are recording of the detected weight and the time elapsed prior to the detection event. The merits of DETEC are finally demonstrated in two typical applications.

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

    Science.gov (United States)

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

    2016-04-12

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

  17. Some characteristics of X-ray imaging for energy region of over 100 keV using plastic scintillation fiber array

    Institute of Scientific and Technical Information of China (English)

    TANG Shibiao; MA Qingli; YIN Zejie; HUANG Huan

    2007-01-01

    In this work, characteristics of using PSFs (plastic scintillation fibers) coupled with CCD (charge-coupled devices ) to build area detectors for high energy X-ray imaging are studied with a Monte Carlo simulation, which cover an energy range of a few hundred kev to about 20 MeV. It was found that the efficiency of PSF in detecting X-ray with energy above a few hundred kev is low. We can use large incident flux to increase the output signal to noise ratio (SNR). The performance can also be improved by coating PSF with X-ray absorption layers and the MTF of the system is presented. By optimizing the absorption layer thickness, the crosstalk of the area detector built with PSF decreases.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lessard, Francois; Archambault, Louis; Plamondon, Mathieu [Departement de physique, de genie physique et d' optique, Universite Laval, Quebec, Quebec G1K 7P4, Canada and Departement de radio-oncologie, Hotel-Dieu de Quebec, Centre hospitalier universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de physique, de genie physique et d' optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Departement de radio-oncologie, Hotel-Dieu de Quebec, Centre hospitalier universitaire de Quebec, Quebec G1R 2J6 (Canada) and Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Departement de physique, de genie physique et d' optique, Universite Laval, Quebec, Quebec G1K 7P4, Canada and Departement de radio-oncologie, Hotel-Dieu de Quebec, Centre hospitalier universitaire de Quebec, Quebec G1R 2J6 (Canada); and others

    2012-09-15

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

  19. Dose rate effects in the radiation damage of the plastic scintillators of the CMS Hadron Endcap Calorimeter

    CERN Document Server

    Khachatryan, V.

    2016-01-01

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

  20. PALS investigations of free volumes thermal expansion of J-PET plastic scintillator synthesized in polystyrene matrix

    CERN Document Server

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

    2015-01-01

    The polystyrene dopped with 2,5-diphenyloxazole as a primary fluor and 2-(4-styrylphenyl)benzoxazole as a wavelength shifter, prepared as a plastic scintillator was investigated using positronium probe in wide range of temperatures from 123 to 423 K. Three structural transitions at 260 K, 283 K and 370 K were found in the material. In the o-Ps intensity dependence on temperature, the significant hysteresis is observed. Heated to 370 K, the material exhibits the o-Ps intensity variations in time.

  1. Radiostrontium separation and measurement in a single step using plastic scintillators plus selective extractants. Application to aqueous sample analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bagan, H.; Tarancon, A.; Rauret, G. [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Garcia, J.F., E-mail: jfgarcia@ub.edu [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain)

    2011-02-07

    This study describes a new protocol for {sup 90}Sr determination in water samples based on the use of a selective extractant (DtBuCH18C6) and plastic scintillator microspheres. The proposed procedure unifies chemical separation and sample measurement preparation in a single step to reduce the effort, time and reagents required for analysis. In addition, the final measurement does not produce mixed waste. The minimum activity detectable for 10 mL of sample solution is 0.46 Bq L{sup -1}. Relative errors for the determination of {sup 90}Sr activity in drinking, sea and river waters are less than 4%.

  2. PALS investigations of free volumes thermal expansion of J-PET plastic scintillator synthesized in polystyrene matrix

    Directory of Open Access Journals (Sweden)

    Wieczorek Anna

    2015-12-01

    Full Text Available The polystyrene doped with 2,5-diphenyloxazole as a primary fluor and 2-(4-styrylphenylbenzoxazole as a wavelength shifter prepared as a plastic scintillator was investigated using positronium probe in wide range of temperatures from 123 to 423 K. Three structural transitions at 260, 283, and 370 K were found in the material. In the o-Ps intensity dependence on temperature, the significant hysteresis is observed. Heated to 370 K, the material exhibits the o-Ps intensity variations in time.

  3. Non-Carbon Dyes For Platic Scintillators- Report

    Energy Technology Data Exchange (ETDEWEB)

    Teprovich, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Gaillard, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sexton, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Ward, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Velten, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-19

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

  4. Temperature variations as a source of uncertainty in medical fiber-coupled organic plastic scintillator dosimetry

    DEFF Research Database (Denmark)

    Buranurak, Siritorn; Andersen, Claus Erik; Beierholm, Anders Ravnsborg

    2013-01-01

    commonly used scintillating fibers would change with temperature in the clinical range (15–40 °C). The study showed that the light yield in the peak regions of the scintillators studied decreases linearly with increasing temperature. For the blue BCF-12 and the green BCF-60 from Saint-Gobain, France we...... found temperature coefficients of −0.15 ± 0.01%/K and −0.55 ± 0.04%/K, respectively. These values are sufficiently large to warrant careful consideration for clinical measurements. © 2013 Elsevier Ltd. All rights reserved....

  5. Study of influence of plastic scintillators thicknesses to detect Beta particles and Gamma radiation by means of spectral analysis of {sup 90}Sr, {sup 90}Y and {sup 137}Cs sources

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas, Jose Patricio Nahuel; Filho, Tufic Madi; Pereira, Maria da Conceicao Costa; Santos, Brianna B. dos; Correa, Eduardo de L.; Santos, Lucas Rodrigues dos; Lopes, Anderson Figueredo; Silva, Alexandre F.P. da; Santos, Diogo F. dos; Camilo, Douglas de S.; Purgato, Rafael T.; Aredes, Vitor O.G. [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP, Av. Prof. Lineu Prestes 2242 Cid Universitaria CEP: 05508-000- Sao Paulo-SP (Brazil)

    2015-07-01

    The Nuclear and Energy Research Institute - IPEN, offers post-graduate programs, namely: Nuclear Technology - Applications (TNA), Nuclear Technology - Materials (TNM), Nuclear Technology - Reactors (TNR). The Institute programs mission is to form expert technicians, physicists and engineers with a strong knowledge in their discipline to work in the nuclear area. The course: 'Theoretical Fundamentals and Practices of the Instrumentation used in Nuclear Data Acquisition' covers the use of laboratory nuclear instrumentation and the accomplishment of experiments to obtain nuclear parameters. One of these experimental exercises is object of this work: 'Study of influence of plastic scintillators to detect Beta particles and Gamma radiation by means of spectral analysis of {sup 90}Sr, {sup 90}Y and {sup 137}Cs sources'. The use of scintillators plastic for the detection has the advantage of low cost, high mechanical strength, is not hygroscopic and can be manufactured in large volumes. This work aims to present the analysis of relative efficiency of detection of plastic scintillators of various thicknesses for beta particles and gamma radiation by the spectrum of {sup 137}Cs and {sup 90}Sr. Due to lack of resolution of the detectors plastic scintillators we worked with relative efficiency. The evaluation was done by reading deposited energy, using the software MAESTRO, for each detector thickness. For beta particles was observed an ideal thickness around 3 mm and the better photon efficiency was observed with increasing the thickness of the detector. The present experiment does not intend to establish a new technique for this subject: it solely aims student's practical exercises in nuclear properties of elements and detectors being part of the nuclear experimental course. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.C.

    1998-03-01

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

  7. Development of large area gamma-ray camera with GSO(Ce) scintillator arrays and PSPMTs

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, H. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan)]. E-mail: nisimura@cr.scphys.kyoto-u.ac.jp; Hattori, K. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan); Kabuki, S. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan); Kubo, H. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan); Miuchi, K. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan); Nagayoshi, T. [Advanced Research Institute for Science and Engineering, Waseda University, 17 Kikui-cho, Shinjyuku, Tokyo 162-0044 (Japan); Okada, Y. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan); Orito, R. [Department of Physics, Graduate School of Science and Technology, Kobe University, 1-1 Rokkoudai, Nada, Kobe 657-8501 (Japan); Sekiya, H. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan); Takada, A. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan); Takeda, A. [Kamioka Observatory, ICRR, University of Tokyo, 456 Higasi-mozumi, Hida-shi, Gifu 506-1205 (Japan); Tanimori, T. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan); Ueno, K. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Sakyo, Kyoto 606-8502 (Japan)

    2007-04-01

    We have developed a position-sensitive scintillation camera with a large area as an absorber of an advanced Compton gamma-ray camera. At first we tested GSO(Ce) crystals. We compared light output from the GSO(Ce) crystals under various conditions: the method of surface polishing, the concentration of Ce, and co-doping Zr. As a result, we chose the GSO(Ce) crystals doped only 0.5mol% Ce, surface of which was polished by chemical etching for the scintillator of our camera. We also made a 16x16cm{sup 2} scintillation camera which consisted of nine position-sensitive PMTs (PSPMTs Hamamatsu flat-panel H8500 ), the each of which had 8x8 anodes with a pitch of 6mm and coupled to 8x8 arrays of pixelated 6x6x13mm{sup 3} GSO(Ce) scintillators. For the readout system of 576 anodes of the PMTs, we used chained resistors to reduce the number of readout channels down to 48 for saving power consumption. The camera has the position resolution of less than 6mm and a typical energy resolution of 10.5% (FWHM) at 662keV at each pixel in a large area of 16x16cm{sup 2}. Furthermore, we constructed a 16x16 array of 3x3x13mm{sup 3} pixelated GSO(Ce) scintillators, and glued it to a PMT H8500. This camera had the position resolution of less than 3mm in area of 5x5cm{sup 2}, except for some of edge pixels; the energy resolution was typically 13% (FWHM) at 662keV.

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

    Energy Technology Data Exchange (ETDEWEB)

    Filipenko, Mykhaylo; Hufschmidt, Patrick; Anton, Gisela; Gleixner, Thomas; Wagenpfeil, Michael; Michel, Thilo [University of Erlangen-Nuremberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Iskhakov, Timur; Leuchs, Gerd [Max-Planck Institute for the Science of Light, Erlangen (Germany); Campbell, Michael; Tick, Timo [European Organization for Nuclear Research, CERN, Geneve 23 (Switzerland); Vallerga, John [University of California, Experimental Astrophysics Group, Space Science Laboratory, Berkeley, CA (United States)

    2014-11-15

    The reconstruction of particle trajectories makes it possible to distinguish between different types of charged particles. In high-energy physics, where trajectories are rather long (several meters), large size trackers must be used to achieve sufficient position resolution. However, in low-background experiments like the search for neutrinoless double beta decay, tracks are rather short (some mm to several cm, depending on the detector in use) and three-dimensional trajectories could only be resolved in gaseous time-projection chambers so far. For detectors of a large volume of around one cubic meter (large in the scope of neutrinoless double beta search) and therefore large drift distances (several decimeters to 1 m), this technique is limited by diffusion and repulsion of charge carriers. In this work we present a ''proof-of-principle'' experiment for a new method of the three-dimensional tracking of charged particles by scintillation light: we used a setup consisting of a scintillator, mirrors, lenses, and a novel imaging device (the hybrid photon detector) in order to image two projections of electron tracks through the scintillator. We took data at the T-22 beamline at DESY with relativistic electrons with a kinetic energy of 5 GeV and from this data successfully reconstructed their three-dimensional propagation path in the scintillator. With our setup we achieved a position resolution in the range of 170-248 μm. (orig.)

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

    CERN Document Server

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

    2013-01-01

    We developed a new sub-nanosecond time-resolved instrument to study the dynamics of UV-visible luminescence under high stopping power heavy ion irradiation. We applied our instrument, called SPORT, on a fast plastic scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean electronic stopping power of 2.6 MeV/\\mu m. As a consequence of increasing permanent radiation damages with increasing ion fluence, our investigations reveal a degradation of scintillation intensity together with, thanks to the time-resolved measurement, a decrease in the decay constant of the scintillator. This combination indicates that luminescence degradation processes by both dynamic and static quenching, the latter mechanism being predominant. Under such high density excitation, the scintillation deterioration of BC-400 is significantly enhanced compared to that observed in previous investigations, mainly performed using light ions. The observed non-linear behaviour implies that the dose at which luminescence starts deteri...

  10. Recent developments of ion beam induced luminescence: radiation hardness study of thin film plastic scintillators

    Science.gov (United States)

    Quaranta, Alberto

    2005-10-01

    Ion beam induced luminescence (IBIL) measurements have been performed on thin film scintillators based on polyvinyltoluene (PVT) and 6FDA-DAD and BPDA-3F polyimides with H+ (1.85 MeV) and He+ (1.8-2.2 MeV) ion beams. The radiation hardness of the undoped polymers has been verified to depend mainly on the deposited energy density, polyimides exhibiting a higher resistance with respect to PVT. In PVT a new fluorescence band, attributed to the radical precursors of the network crosslinking, has been observed. The efficiency of doped polymers degradates with a higher rate, depending on the dye intrinsic lability. At high radiation fluences, the relative efficiency to NE102 of doped polyimides scintillators increases owing to the intrinsic host improved resistance.

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

    CERN Document Server

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

    2016-01-01

    We present a study of the application of the Jagiellonian Positron Emission Tomograph (J-PET) for the registration of gamma quanta from decays of ortho-positronium (o-Ps). The J-PET is the first positron emission tomography scanner based on organic scintillators in contrast to all current PET scanners based on inorganic crystals. Monte Carlo simulations show that the J-PET as an axially symmetric and high acceptance scanner can be used as a multi-purpose detector well suited to pursue research including e.g. tests of discrete symmetries in decays of ortho-positronium in addition to the medical imaging. The gamma quanta originating from o-Ps decay interact in the plastic scintillators predominantly via the Compton effect, making the direct measurement of their energy impossible. Nevertheless, it is shown in this paper that the J-PET scanner will enable studies of the o-Ps$\\to3\\gamma$ decays with angular and energy resolution equal to $\\sigma(\\theta) \\approx 0.4^{\\circ}$ and $\\sigma(E) \\approx 4.1$ keV, respect...

  12. A gas scintillation counter with imaging optics and large area UV-detector

    Energy Technology Data Exchange (ETDEWEB)

    Nickles, J. E-mail: nickles@hsb.uni-frankfurt.de; Braeuning, H.; Braeuning-Demian, A.; Dangendorf, V.; Breskin, A.; Chechik, R.; Rauschnabel, K.; Schmidt-Boecking, H

    2002-01-21

    We report on the improvements in the position sensitive readout of a xenon-filled gas scintillation proportional counter. Using an imaging optic for UV-light in the region of 170 nm, the position resolution could be improved by more than 30%. In addition, we have obtained first encouraging results for the use of the recently developed gas electron multiplier together with a CsI-photocathode as a large area UV-detector system.

  13. A gas scintillation counter with imaging optics and large area UV-detector

    CERN Document Server

    Nickles, J; Bräuning-Demian, A; Breskin, Amos; Chechik, R; Dangendorf, V; Rauschnabel, K; Schmidt-Böcking, H

    2002-01-01

    We report on the improvements in the position sensitive readout of a xenon-filled gas scintillation proportional counter. Using an imaging optic for UV-light in the region of 170 nm, the position resolution could be improved by more than 30%. In addition, we have obtained first encouraging results for the use of the recently developed gas electron multiplier together with a CsI-photocathode as a large area UV-detector system.

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

    Energy Technology Data Exchange (ETDEWEB)

    Couture, A.

    2013-06-07

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

  15. Proposal of a Novel Setup for Linac Monitoring Using a Specifically Designed Plastic Scintillator and a Spectrophotometer

    Directory of Open Access Journals (Sweden)

    F. Moreno-Barbosa

    2016-08-01

    Full Text Available In this work we report the design, implementation and results of an alternative monitoring system for a linear accelerator (LINAC used in medical therapy. The system proposed consist in as lab of scintillator plastic with a wavelength shifter fiberoptically coupled to collect the light generated,and a Spectrophotometer Ocean Optics USB4000 as analyzer. The control was made with two computers, one into the therapy room and another, using a VNC (Virtual Network Computer and Ethernet wire, outside of the room in order to avoid radiation exposure. The LINAC dose range covered was 1, 2, 3, 4, 5, 10, 20, 30 and 40 Monitor Units (MU with 6 and 18 MeV energy photons. The spectrum obtained was compared with the measures of the LINAC ionization camera used to calibrate it. The results obtained allow us to propose this device as an alternative method to monitor the LINAC performance.

  16. Evaluation of phase bunching in the central region of a cyclotron by a radial probe with a plastic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Miyawaki, Nobumasa, E-mail: miyawaki.nobumasa@jaea.go.jp [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Fukuda, Mitsuhiro [Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Arakawa, Kazuo [Gunma University Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-Machi, Maebashi, Gunma, 371-8511 (Japan); Kamiya, Tomihiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2014-12-11

    A new technique for evaluating the phase bunching performance in the central region of a cyclotron was developed. A newly-developed radial probe with a 6-mm-wide, 5-mm-height plastic scintillator was applied to analysis of the correlation between the internal beam phase distribution and the initial beam phase, defined by adjusting the relative RF phase of the beam buncher. The phase distribution measurement system, comprising the radial probe equipped with a plastic scintillator and the signal-processing modules, had a sufficiently good time resolution of 45 ps full-width at half-maximum for the phase bunching evaluation. The correlations between the buncher phase and the measured phase distribution for the acceleration harmonic number h=1 and 2 were consistent with the calculation result of the geometric trajectory analysis. For h=1 case of a 107 MeV {sup 4}He{sup 2+} beam, the internal beam phase region spread over 71 RF degrees full-width at quarter-maximum (FWQM) for the acceptable buncher phase region of 48 RF degrees, and no evidence of the phase bunching effect was observed. For h=2 case of a 260 MeV {sup 20}Ne{sup 7+} beam, the internal beam phase region for the acceptable buncher phase region of 59 RF degrees was compressed into 21 RF degrees FWQM. The phase bunching effect was sharply evident for h=2, and contributed to increase of the acceptable beam phase region and the beam intensity per phase width.

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

    Science.gov (United States)

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

    2013-02-01

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

  18. Performance of a Large Area Avalanche Photodiode in a Liquid Xenon Ionization and Scintillation Chamber

    CERN Document Server

    Ni, K; Day, D; Giboni, K L; Lopes, J A M; Majewski, P; Yamashita, M

    2005-01-01

    Scintillation light produced in liquid xenon (LXe) by alpha particles, electrons and gamma-rays was detected with a large area avalanche photodiode (LAAPD) immersed in the liquid. The alpha scintillation yield was measured as a function of applied electric field. We estimate the quantum efficiency of the LAAPD to be 45%. The best energy resolution from the light measurement at zero electric field is 7.5%(sigma) for 976 keV internal conversion electrons from Bi-207 and 2.6%(sigma) for 5.5 MeV alpha particles from Am-241. The detector used for these measurements was also operated as a gridded ionization chamber to measure the charge yield. We confirm that using a LAAPD in LXe does not introduce impurities which inhibit the drifting of free electrons.

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

    Science.gov (United States)

    Ghal-Eh, N; Green, S

    2016-06-01

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

  20. A pilot study of the novel J-PET plastic scintillator with 2-(4-styrylphenyl)benzoxazole as a wavelength shifter

    CERN Document Server

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

    2015-01-01

    For the first time a molecule of 2-(4-styrylphenyl)benzoxazole containing benzoxazole and stilbene groups is applied as a scintillator dopant acting as a wavelength shifter. In this article a light yield of the plastic scintillator, prepared from styrene doped with 2 wt% of 2,5-diphenylbenzoxazole and 0.03 wt% of 2-(4-styrylphenyl)benzoxazole, is determined to be as large as 60% $\\pm$ 2% of the anthracene light output. There is a potential to improve this value in the future by the optimization of the additives concentrations.

  1. Optimization of light yield by injection of the optical filler into the co extruded hole of plastic scintillation bar with WLS fiber in it

    CERN Document Server

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

    2016-01-01

    Results of the measurements with cosmic muons for the light yield of 2-meter long extruded scintillation bar (strip) as a function of distance for different options for light collection technique are presented. Scintillation strip cross section geometry was a triangle made on polystyrene plastic scintillator with dopants of 2% PTP and 0.03% POPOP, extruded with 2.6 mm diameter hole and produced at ISMA (Kharkov, Ukraine). It was shown that the insertion of the optical transparent resin (BC 600 or CKTN MED(E)) by special technique into the co-extruded hole with 1.0 mm or 1.2 mm wave-length shifter (WLS) fiber Kuraray Y11 (200) MC in it significantly improves light collection by factor of 1.6...1.9 against of the 'dry' case.

  2. Memory effect, resolution, and efficiency measurements of an Al{sub 2}O{sub 3} coated plastic scintillator used for radioxenon detection

    Energy Technology Data Exchange (ETDEWEB)

    Bläckberg, L., E-mail: lisa.blackberg@physics.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Fritioff, T.; Mårtensson, L.; Nielsen, F.; Ringbom, A. [Division of Defence and Security Systems, Swedish Defence Research Agency (FOI), SE-17290 Stockholm (Sweden); Sjöstrand, H.; Klintenberg, M. [Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

    2013-06-21

    A cylindrical plastic scintillator cell, used for radioxenon monitoring within the verification regime of the Comprehensive Nuclear-Test-Ban Treaty, has been coated with 425 nm Al{sub 2}O{sub 3} using low temperature Atomic Layer Deposition, and its performance has been evaluated. The motivation is to reduce the memory effect caused by radioxenon diffusing into the plastic scintillator material during measurements, resulting in an elevated detection limit. Measurements with the coated detector show both energy resolution and efficiency comparable to uncoated detectors, and a memory effect reduction of a factor of 1000. Provided that the quality of the detector is maintained for a longer period of time, Al{sub 2}O{sub 3} coatings are believed to be a viable solution to the memory effect problem in question.

  3. A new imaging device based on UV scintillators and a large area gas photomultiplier

    Energy Technology Data Exchange (ETDEWEB)

    Sekiya, H., E-mail: sekiya@icrr.u-tokyo.ac.jp [Kamioka Observatory, Institute for Cosmic Ray Research, Univeristy of Tokyo, 456, Higashi-Mozumi Hida, Gifu 506-1205 (Japan); Kamioka Satellite, Institute for the Physics and Mathematics of the Universe, 456, Higashi-Mozumi Hida, Gifu 506-1205 (Japan); Ida, C.; Kubo, H.; Kurosawa, S.; Miuchi, K.; Tanimori, T.; Taniue, K. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502 (Japan); Yoshikawa, A.; Yanagida, T.; Yokota, Y. [Institute of Multidisciplinary, Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba, Sendai, Miyagi 980-8577 (Japan); Fukuda, K.; Ishizu, S.; Kawaguchi, N.; Suyama, T. [Tokuyama Corporation, 3-3-1, Shibuya, Shibuya, Tokyo 150-8383 (Japan)

    2011-05-15

    A new type high spatial resolution radiation detector based on a UV scintillator+a UV imaging gas photomultiplier is presented. The prototype UV detector consists of a 10 cmx10 cm {mu}PIC, 2 GEMs and a semitransparent CsI photocathode deposited on a MgF{sub 2} window. The effective photo-sensitive area is {phi}34 mm and the readouts are 400 {mu}m pitch strips. A newly developed 20 mm size LaF{sub 3}(Nd) crystal which emits 172 nm photons is coupled to the detector for the first step. The detector was tested in pulse mode operation with 5.5 MeV {alpha} particles from {sup 241}Am. The single photoelectrons were successfully detected and the images of the crystal shape were clearly obtained.

  4. Relation Between Coronal Hole Areas and Solar Wind Speeds Derived from Interplanetary Scintillation Measurements

    Science.gov (United States)

    Tokumaru, Munetoshi; Satonaka, Daiki; Fujiki, Ken'ichi; Hayashi, Keiji; Hakamada, Kazuyuki

    2017-03-01

    We investigate the relation between coronal hole (CH) areas and solar wind speeds during 1995 - 2011 using the potential field (PF) model analysis of magnetograph observations and interplanetary scintillation (IPS) observations by the Institute for Space-Earth Environmental Research (formerly Solar-Terrestrial Environment Laboratory) of Nagoya University. We obtained a significant positive correlation between the CH areas (A) derived from the PF model calculations and solar wind speeds (V) derived from the IPS observations. The correlation coefficients between them are usually high, but they drop significantly in solar maxima. The slopes of the A - V relation are roughly constant except for the period around solar maximum, when flatter or steeper slopes are observed. The excursion of the correlation coefficients and slopes at solar maxima is ascribed partly to the effect of rapid structural changes in the coronal magnetic field and solar wind, and partly to the predominance of small CHs. It is also demonstrated that V is inversely related to the flux expansion factor (f) and that f is closely related to A^{-1/2}; hence, V ∝ A^{1/2}. A better correlation coefficient is obtained from the A^{1/2} - V relation, and this fact is useful for improving space weather predictions. We compare the CH areas derived from the PF model calculations with He i 1083 nm observations and show that the PF model calculations provide reliable estimates of the CH area, particularly for large A.

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

    Science.gov (United States)

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

    2013-12-01

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

  6. Modeling interactions of intermediate-energy neutrons in a plastic scintillator array with GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Kohley, Z., E-mail: zkohley@gmail.com [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Lunderberg, E.; DeYoung, P.A. [Department of Physics, Hope College, Holland, MI 49423 (United States); Roeder, B.T. [LPC-Caen, ENSICAEN, IN2P3/CNRS et Universite de Caen, 14050 Caen cedex (France); Baumann, T. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Christian, G.; Mosby, S.; Smith, J.K.; Snyder, J.; Spyrou, A.; Thoennessen, M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2012-08-01

    A Monte Carlo simulation of a large-area neutron time-of-flight detector, built on the GEANT4 framework, has been compared with an experimental measurement of the {sup 16}B{yields}{sup 15}B+n decay produced from a 55 MeV/u{sup 17}C beam. The ability of the Monte Carlo simulation to reproduce the intermediate-energy neutron interactions within the detector has been explored using both the stock GEANT4 physics processes and a custom neutron interaction model, MENATE{sub R}. The stock GEANT4 physics processes were unable to reproduce the experimental observables, while excellent agreement was obtained through the inclusion of the MENATE{sub R} model within GEANT4. The differences between the two approaches are shown to be related to the modeling of the neutron-carbon inelastic reactions. Additionally, the use of MENATE{sub R} provided accurate reproduction of experimental signals associated with neutron scattering within the detector. These results provide validation of the Monte Carlo simulation for modeling measurements of multiple neutrons where the identification and removal of false neutron signals, due to multiple neutron scattering, are required.

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

    Science.gov (United States)

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

    2014-11-01

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

  8. Silicon photomultiplier readout of a monolithic 270$\\times$5$\\times$5 cm$^3$ plastic scintillator bar for time of flight applications

    CERN Document Server

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

    2016-01-01

    The detection of 200-1000 MeV neutrons requires large amounts, $\\sim$100 cm, of detector material because of the long nuclear interaction length of these particles. In the example of the NeuLAND neutron time-of-flight detector at FAIR, this is accomplished by using 3000 monolithic scintillator bars of 270$\\times$5$\\times$5 cm$^3$ size made of a fast plastic. Each bar is read out on the two long ends, and the needed time resolution of $\\sigma_t$ $<$ 150 ps is reached with fast timing photomultipliers. In the present work, it is investigated whether silicon photomultiplier (SiPM) photosensors can be used instead. Experiments with a picosecond laser system were conducted to determine the timing response of the assembly made up of SiPM and preamplifier. The response of the full system including also the scintillator was studied using 30 MeV single electrons provided by the ELBE superconducting electron linac. The ELBE data were matched by a simple Monte Carlo simulation, and they were found to obey an inverse-...

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

    Science.gov (United States)

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

    2016-04-01

    The detection of 200-1000 MeV neutrons requires large amounts, ~ 100 cm, of detector material because of the long nuclear interaction length of these particles. In the example of the NeuLAND neutron time-of-flight detector at FAIR, this is accomplished by using 3000 monolithic scintillator bars of 270 × 5 × 5cm3 size made of a fast plastic. Each bar is read out on the two long ends, and the needed time resolution of σt ELBE superconducting electron linac. The ELBE data were matched by a simple Monte Carlo simulation, and they were found to obey an inverse-square-root scaling law. In the electron beam tests, a time resolution of σt = 136 ps was reached with a pure SiPM readout, well within the design parameters for NeuLAND.

  10. A lens-coupled scintillation counter in cryogenic environment

    CERN Document Server

    Stoykov, A; Amato, A; Bartkowiak, M; Konter, J A; Rodriguez, J; Sedlak, K

    2011-01-01

    In this work we present an elegant solution for a scintillation counter to be integrated into a cryogenic system. Its distinguishing feature is the absence of a continuous light guide coupling the scintillation and the photodetector parts, operating at cryogenic and room temperatures respectively. The prototype detector consists of a plastic scintillator with glued-in wavelength-shifting fiber located inside a cryostat, a Geiger-mode Avalanche Photodiode (G-APD) outside the cryostat, and a lens system guiding the scintillation light re-emitted by the fiber to the G-APD through optical windows in the cryostat shields. With a 0.8mm diameter multiclad fiber and a 1mm active area G-APD the coupling efficiency of the "lens light guide" is about 50%. A reliable performance of the detector down to 3K is demonstrated.

  11. Development of a Real-Time, Large Area, High Spatial Resolution Particle Tracker Based on Scintillating Fibers

    Directory of Open Access Journals (Sweden)

    D. Lo Presti

    2014-01-01

    Full Text Available The design of a detector for tracking charged particles is presented together with the characterization techniques developed to extract the main design specifications. The goals for the final detector are to achieve real-time imaging performances, a large detection area, and a high spatial resolution, particularly suitable for medical imaging applications. This paper describes the prototype of the tracker plane, which has a 20 × 20 cm2 sensitive area consisting of two crossed ribbons of 500 μm square scintillating fibers. The information about the hit position extracted real-time tracker in an innovative way, using a reduced number of the read-out channels to obtain a very large detection area but with moderate costs and complexity. The performances of the tracker have been investigated using β sources, cosmic rays, and a 62 MeV proton beam.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-15

    Purpose: The objective of this work is to present a new 2D plastic scintillation detectors array (2D-PSDA) designed for the dosimetry of megavoltage (MV) energy photon beams in radiation therapy and to characterize its basic performance. Methods: We developed a 2D detector array consisting of 781 plastic scintillation detectors (PSDs) inserted into a plane of a water-equivalent phantom. The PSDs were distributed on a 26 x 26 cm{sup 2} grid, with an interdetector spacing of 10 mm, except for two perpendicular lines centered on the detection plane, where the spacing was 5 mm. Each PSD was made of a 1 mm diameter by 3 mm long cylindrical polystyrene scintillating fiber coupled to a clear nonscintillating plastic optical fiber. All of the light signals emitted by the PSDs were read simultaneously with an optical system at a rate of one measurement per second. We characterized the performance of the optical system, the angular dependency of the device, and the perturbation of dose distributions caused by the hundreds of PSDs inserted into the phantom. We also evaluated the capacity of the system to monitor complex multileaf collimator (MLC) sequences such as those encountered in step-and-shoot intensity modulated radiation therapy (IMRT) plans. We compared our results with calculations performed by a treatment planning system and with measurements taken with a 2D ionization chamber array and with a radiochromic film. Results: The detector array that we developed allowed us to measure doses with an average precision of better than 1% for cumulated doses equal to or greater than 6.3 cGy. Our results showed that the dose distributions produced by the 6-MV photon beam are not perturbed (within {+-}1.1%) by the presence of the hundreds of PSDs located into the phantom. The results also showed that the variations in the beam incidences have little effect on the dose response of the device. For all incidences tested, the passing rates of the gamma tests between the 2D-PSDA and

  13. POSSuMUS: a position sensitive scintillating muon SiPM detector

    CERN Document Server

    Ruschke, Alexander

    The development of a modular designed large scale scintillation detector with a two-dimensional position sensitivity is presented in this thesis. This novel POsition Sensitive Scintillating MUon SiPM Detector is named POSSuMUS. The POSSuMUS detector is capable to determine the particle’s position in two space dimensions with a fast trigger capability. Each module is constructed from two trapezoidal shaped plastic scintillators to form one rectangular shaped detector module. Both trapezoids are optically insulated against each other. In both trapezoids the scintillation light is collected by plastic fibers and guided towards silicon photomultipliers (SiPMs). SiPMs are light sensors which are capable to detect even smallest amounts of light. By combining several detector modules, position sensitive areas from 100 cm2 to few m2 are achievable with few readout channels. Therefore, POSSuMUS provides a cost effective detector concept. The position sensitivity along the trapezoidal geometry of one detector module ...

  14. Scintillation detectors of Alborz-I experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pezeshkian, Yousef [Department of Physics, Sharif University of Technology, P.O.Box 11155-9161, Tehran (Iran, Islamic Republic of); Alborz Observatory, Sharif University of Technology, P.O.Box 11155-9161, Tehran (Iran, Islamic Republic of); Bahmanabadi, Mahmud, E-mail: bahmanabadi@sharif.edu [Department of Physics, Sharif University of Technology, P.O.Box 11155-9161, Tehran (Iran, Islamic Republic of); Alborz Observatory, Sharif University of Technology, P.O.Box 11155-9161, Tehran (Iran, Islamic Republic of); Abbasian Motlagh, Mehdi; Rezaie, Masume [Alborz Observatory, Sharif University of Technology, P.O.Box 11155-9161, Tehran (Iran, Islamic Republic of)

    2015-02-11

    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 m{sup 2} will be covered by 20 plastic scintillation detectors (each with an area of 50×50 cm{sup 2}). 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.

  15. Scintillation detectors of Alborz-I experiment

    CERN Document Server

    Pezeshkian, Yousef; Motlagh, Mehdi Abbasian; Rezaie, Masoume

    2014-01-01

    A new air shower experiment of the Alborz Observatory, Alborz-I, located at the Sharif University of Technology, Iran, will be constructed in near future. An area of about 30$\\times$40 m$^{2}$ will be covered by 20 plastic scintillation detectors (each with an area of 50$\\times$50 cm$^{2}$). 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 Geant4 simulation. There is a good agreement between 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Eberly, Brandon M. [Univ. of Pittsburgh, PA (United States)

    2014-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  18. Determination of oil reservoir radiotracer (S{sup 14}CN{sup -}) in a single step using a plastic scintillator extractive resin

    Energy Technology Data Exchange (ETDEWEB)

    Bagan, H.; Tarancon, A. [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona (Spain); Stavsetra, L. [Department for Reservoir and Exploration Technology, Institute for Energy Technology (IFE), Instituttveien 18, N-2027 Kjeller (Norway); Rauret, G. [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona (Spain); Garcia, J.F., E-mail: jfgarcia@ub.edu [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona (Spain)

    2012-07-29

    Highlights: Black-Right-Pointing-Pointer A new procedure for S{sup 14}CN{sup -} radiotracer determination using PS resin was established. Black-Right-Pointing-Pointer The minimum detectable activity for a 100 mL sample is 0.08 Bq L{sup -1}. Black-Right-Pointing-Pointer The minimum quantifiable activity for a 100 mL sample is 0.31 Bq L{sup -1}. Black-Right-Pointing-Pointer PS resin is capable to quantify S{sup 14}CN{sup -} radiotracer samples with errors lower than 5%. Black-Right-Pointing-Pointer PS resin is also capable to quantify complex matrices obtained from oil reservoirs. - Abstract: The analysis of radiotracers is important in the study of oil reservoir dynamics. One of the most widely used radiotracer is S{sup 14}CN{sup -}. Prior to activity measurements by Liquid Scintillation (LS), routine determinations require the pretreatment steps of purification and concentration of the samples using anion exchange columns. The final elution media produces samples with high salt concentration that may lead to problems with phase separation during the LS measurement. Plastic Scintillation (PS) is an alternative technique that provides a solid surface that can be used as a platform for the immobilisation of selective extractants to obtain a PS resin. The proposed procedure unifies chemical separation and sample measurement preparation in a single step, serving to reduce the number of reagents needed and manpower required for the analysis while also avoiding mixed waste production by LS. The objective of this study is to develop a PS resin for the determination of {sup 14}C-labelled thiocyanate radiotracer in water samples. For this purpose, the immobilisation procedure was optimised, including optimisation of the proportion of PS microspheres:extractant and the use of a control blank to monitor the PS resin immobilisation process. The breakthrough volume was studied and the detection and quantification limits for 100 mL of sample were determined to be 0.08 Bq L{sup -1

  19. Primary 4{pi}{beta}-{gamma} coincidence system for standardization of radionuclides by means of plastic scintillators; Sistema primario por coincidencias 4{pi}{beta}-{gamma} para a padronizacao de radionuclideos empregando cintiladores plasticos

    Energy Technology Data Exchange (ETDEWEB)

    Baccarelli, Aida Maria

    2003-07-01

    The present work describes a 4{pi}({alpha},{beta})-{gamma} coincidence system for absolute measurement of radionuclide activity using a plastic scintillator in 4{pi} geometry for charged particles detection and a Nal (Tl) crystal for gamma-ray detection. Several shapes and dimensions of the plastic scintillator have been tried in order to obtain the best system configuration. Radionuclides which decay by alpha emission, {beta}{sup -}, {beta}{sup +} and electron capture have been standardized. The results showed excellent agreement with other conventional primary system which makes use of a 4{pi} proportional counter for X-ray and charged particle detection. The system developed in the present work have some advantages when compared with the conventional systems, namely; it does not need metal coating on the films used as radioactive source holders. When compared to liquid scintillators, is showed the advantage of not needing to be kept in dark for more than 24 h to allow phosphorescence decay of ambient light. Therefore it can be set to count immediately after the sources are placed inside of it. (author)

  20. Scintillation counter with MRS APD light readout

    CERN Document Server

    INSPIRE-00061314; Malkevich, D.; Martemyanov, A.; Ryabinin, M.; Smirnitsky, A.; Voloshin, K.; Bondarenko, G.; Golovin, V.; Grigoriev, E.

    2005-01-01

    START, a high-efficiency and low-noise scintillation detector for ionizing particles, was developed for the purpose of creating a high-granular system for triggering cosmic muons. Scintillation light in START is detected by MRS APDs (Avalanche Photo-Diodes with Metal-Resistance-Semiconductor structure), operated in the Geiger mode, which have 1 mm^2 sensitive areas. START is assembled from a 15 x 15 x 1 cm^3 scintillating plastic plate, two MRS APDs and two pieces of wavelength-shifting optical fiber stacked in circular coils inside the plastic. The front-end electronic card is mounted directly on the detector. Tests with START have confirmed its operational consistency, over 99% efficiency of MIP registration and good homogeneity. START demonstrates a low intrinsic noise of about 10^{-2} Hz. If these detectors are to be mass-produced, the cost of a mosaic array of STARTs is estimated at a moderate level of 2-3 kUSD/m^2.

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

    Energy Technology Data Exchange (ETDEWEB)

    Vandervoort, E.; Szanto, J. [The Ottawa Hospital Cancer Centre (Canada); Christiansen, E. [The Ottawa Hospital Cancer Centre (Canada); Department of Physics, McGill University (Canada)

    2014-08-15

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

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

    Science.gov (United States)

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

    2014-01-15

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

  3. Design of tissue equivalent scintillators for precise dosimetry purposes

    Energy Technology Data Exchange (ETDEWEB)

    Mainardi, R.T.; Bonzi, E.V. [Universidad Nacional de Cordoba (Argentina). Facultad de Matematica; Martinez, V.D. [Universidad Complutense, Madrid (Spain). Facultad de Medicina

    1997-08-01

    A tissue equivalent plastic scintillator containing chlorine has been designed through Monte Carlo simulations and mass energy transfer coefficient calculations, searching for the optimum concentration of that element whose role is to make the value of the absorbed radiation energy equal in tissue and plastic scintillators. The plastic is obtained by mixing the base component of most current plastic scintillators, Poly-Vinyl-Toluene, with Vinyl-Benzyl-Chloride. In addition, we propose two kinds of plastics, one for diagnostic X-rays and another one for therapy. (author).

  4. Study of a 4{pi}{beta}-{gamma} coincidence system for absolute radionuclide activity measurement using plastic scintillators; Estudo de um sistema de coincidencias 4{pi}{beta}-{gamma} para a medida absoluta de atividade de radionuclideos empregando cintiladores plasticos

    Energy Technology Data Exchange (ETDEWEB)

    Piuvezam Filho, Helio

    2007-07-01

    The present work was intended to study a coincidence system 4{pi}(PS){beta}-{gamma} for absolute activity measurement using plastic scintillators in 4{pi} geometry. Along with experiments on the coincidence system, simulations were also performed applying the Monte Carlo Method, by means of codes PENELOPE and ESQUEMA. These simulations were performed in order to calculate the extrapolation curve of the coincidence system 4{pi}(PS){beta}-{gamma} and compare it to experimental data. A new geometry was proposed to the coincidence system adding up a second photomultiplier tube to the previous system for improving light collection from the plastic scintillator, as this system presented limitations in the minimum detected energy due to the presence of electronic noise and low gain. The results show that an improvement in the signal-to-noise ratio was obtained, as well as in the minimum detected energy. Moreover, there was an increase in the detection efficiency. With these modifications, it is now possible to calibrate radionuclides which emit low energy electrons or X-rays, increasing the number of radionuclides that can be standardized with this type of system.(author)

  5. 用于强γ环境中测量中子参数的薄膜塑料闪烁探测器%Thin Plastic Scintillating Foil for Measuring Pulsed Neutron Flux in High Gamma-Ray Environment

    Institute of Scientific and Technical Information of China (English)

    欧阳晓平; 李真富; 王群书; 霍裕昆

    2005-01-01

    提出了在强γ环境中脉冲中子通量的薄膜闪烁体测量方法. 根据其与中子、γ响应的理论计算结果,研制成功一种对γ不灵敏,用于探测快脉冲中子通量的新型探测器. 该探测器由塑料薄膜闪烁体+光电探测器构成. 与传统探测器相比,该探测器具有如下特点:1.高中子灵敏度;2.高n/γ分辨;3.在给定能区具有平坦的能量响应.%A new conception of measuring pulsed neutron flux in high gamma-ray environment with a thin plastic scintillating foil is presented. Based on the calculations of the response to neutrons and gamma-rays, a new gamma-insensitive detector for detecting fast rising, transient neutron flux has been developed and preliminarily tested, which comprises a thin plastic scintillating foil of ST401 (TPSF) and a photomultiplier tube (or a photodiode). The detector exhibits three distinct properties compared with the conventional ones: (1) high neutron sensitivity, (2) high n/γ discrimination, and (3) flat response in the given neutron energy range.

  6. 提高塑料闪烁体n/γ甄别能力的一种新途径%A New Method of Increasing Neutron/gamma Discrimination of Plastic Scintillator

    Institute of Scientific and Technical Information of China (English)

    冯璟华; 彭太平; 蒙世坚

    2011-01-01

    Plastic scintillator is usually used to detect neutrons in high power pulsed neutron/gamma mixed radiation field. Since gamma rays can make background signals in the scintillator, it needs to take some measures to increase neutron/gamma discrimination. Based on the fact that electrons are much more easily deflected than protons in magnetic field, this text proposes a new method of increasing neutron/gamma discrimination of plastic scintillator. The Geant4 simulation indicates that the new method can be used to measure neutrons in fission mixed radiation field where, in some cases, gamma flux might be as high as two orders of magnitude of neutron flux.%在强脉冲束中子、γ混合辐射场中,一般使用塑料闪烁体探测器测量中子注量,为了尽可能地减少γ辐射的干扰,需要提高塑料闪烁体的n/γ甄别能力.利用电子与质子在磁场中的偏转半径不同,提出一种提高塑料闪烁体n/γ甄别能力的新途径,并采用Geant4输运程序探讨了该探测方法的可行性,模拟结果表明:该方法使用较薄的闪烁体和磁铁构成探测系统,可用于探测γ注量高于中子注量1~2个量级的强γ裂变辐射场中子.

  7. Combined scintillation detector for gamma dose rate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Viererbl, L.; Novakova, O.; Jursova, L. (Tesla, Premysleni (Czechoslovakia). Vyzkumny Ustav Pristroju Jaderne Techniky)

    1990-01-01

    The specifications are described of a newly developed scintillation detector, essentially consisting of a plastic scintillator completed with inorganic scintillators ZnS(Ag) and NaI(Tl). The gamma dose rate is derived from the photomultiplier anode current. The composition and sizes of the scintillators and the capsule are selected so as to minimise the energy dependence errors and directional dependence errors of the detector response over a wide range of energies and/or angles. (author).

  8. Mapping Rural Areas with Widespread Plastic Covered Vineyards Using True Color Aerial Data

    Directory of Open Access Journals (Sweden)

    Eufemia Tarantino

    2012-06-01

    Full Text Available Plastic covering is used worldwide to protect crops against damaging growing conditions. This agricultural practice raises some controversial issues. While it significantly impacts on local economic vitality, plasticulture also shows several environmental affects. In the Apulia Region (Italy the wide-spreading of artificial plastic coverings for vineyard protection has showed negative consequences on the hydrogeological balance of soils as well as on the visual quality of rural landscape. In order to monitor and manage this phenomenon, a detailed site mapping has become essential. In this study an efficient object-based classification procedure from Very High Spatial Resolution (VHSR true color aerial data was developed on eight test areas located in the Ionian area of the Apulia Region in order to support the updating of the existing land use database aimed at plastic covered vineyard monitoring.

  9. Large-area WSe2 electric double layer transistors on a plastic substrate

    KAUST Repository

    Funahashi, Kazuma

    2015-04-27

    Due to the requirements for large-area, uniform films, currently transition metal dichalcogenides (TMDC) cannot be used in flexible transistor industrial applications. In this study, we first transferred chemically grown large-area WSe2 monolayer films from the as-grown sapphire substrates to the flexible plastic substrates. We also fabricated electric double layer transistors using the WSe2 films on the plastic substrates. These transistors exhibited ambipolar operation and an ON/OFF current ratio of ∼104, demonstrating chemically grown WSe2 transistors on plastic substrates for the first time. This achievement can be an important first step for the next-generation TMDC based flexible devices. © 2015 The Japan Society of Applied Physics.

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

    Science.gov (United States)

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

    2000-01-01

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

  11. Molecular origins of scintillation in organic scintillators (Conference Presentation)

    Science.gov (United States)

    Feng, Patrick; Mengesha, Wondwosen; Myllenbeck, Nicholas

    2016-09-01

    Organic-based scintillators are indispensable materials for radiation detection owing to their high sensitivity to fast neutrons, low cost, and tailorable properties. There has been a recent resurgence of interest in organic scintillators due to exciting discoveries related to neutron discrimination and gamma-ray spectroscopy, which represent capabilities previously thought not possible in these materials. I will discuss our development of crystalline and polymer-based scintillators for these applications. Structure-property relationships related to intermolecular interactions and host-guest electronic exchange will be discussed in the context of energy-transfer pathways relevant to scintillation. An emphasis will be placed on the rational design of these materials, as guided by first principles and DFT calculations. Two related topics will be discussed: 1) Incorporation of organometallic triplet-harvesting additives to plastic scintillator matrices to confer a 'two-state' (singlet and triplet) luminescence signature to different types of ionizing radiation. This approach relies upon energetic and spatial overlap between the donor and acceptor excited states for efficient electronic exchange. Key considerations also include synthetic modification of the luminescence spectra and kinetics, as well as the addition of secondary additives to increase the recombination efficiency. 2) Design of organotin-containing plastic scintillators as a route towards gamma-ray spectroscopy. Organometallic compounds were selected on the basis of distance-dependent quenching relationships, phase compatibility with the polymer matrix, and the gamma-ray cross sections. This approach is guided by molecular modeling and radiation transport modeling to achieve the highest possible detection sensitivity luminescence intensity.

  12. Readout of a LaCl sub 3 (Ce sup 3 sup +) scintillation crystal with a large area avalanche photodiode

    CERN Document Server

    Allier, C P; Dorenbos, P; Hollander, R W; Eijk, C W E; Kraemer, K W; Güdel, H U

    2002-01-01

    A high-resolution gamma-ray detector consisting of an 8 mm diameter and 5 mm thick LaCl sub 3 (Ce sup 3 sup +) scintillation crystal coupled to a 16 mm diameter APD from Advanced Photonix Inc is presented. The energy resolution R obtained at 662 keV is about 3.7% (full-width at half maximum). The low intrinsic resolution of about 2%, the high light yield of the crystal (46 000+-5000 photons per MeV) and the high quantum efficiency of the avalanche photodiode make this gamma-ray detector an excellent choice for applications were a high energy resolution is required.

  13. Cocaine-evoked synaptic plasticity of excitatory transmission in the ventral tegmental area.

    Science.gov (United States)

    Lüscher, Christian

    2013-05-01

    Cocaine leads to a strong euphoria, which is at the origin of its recreational use. Past the acute effects, the drug leaves traces in the brain that persist long after it has been cleared from the body. These traces eventually shape behavior such that drug use may become compulsive and addiction develops. Here we discuss cocaine-evoked synaptic plasticity of glutamatergic transmission onto dopamine (DA) neurons of the ventral tegmental area (VTA) as one of the earliest traces after a first injection of cocaine. We review the literature that has examined the induction requirements as well as the expression mechanism of this form of plasticity and ask the question about its functional significance.

  14. Microprocessor-based single particle calibration of scintillation counter

    Science.gov (United States)

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

    1985-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    S. Mukhopadhyay

    2003-06-01

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

  16. Chemical abundances of cosmic rays greater than 4.5 GV measured with a large area proportional counter-scintillation counter stack

    Science.gov (United States)

    Lheureux, J.; Fan, C. Y.; Mainardi, R.; Gloeckler, G.

    1974-01-01

    A 6500 sq cm-ster cosmic-ray detector consisting of 12 gas counter trays sandwiched between two large-area circular scintillation counters was flown from Palestine, Texas in November 1972 to study the composition of primary particles greater than 1.5 GeV/nucleon in the charge range from 3 to 30. For each analyzed event, the particle trajectory was recorded, using four 20-wire proportional counter trays. Also recorded were the energy loss in each of the solid counters and the dE/dx losses in each of the 12 gas counters. The large dynamic range of the detector is established by operating six of the gas counters in the ionization mode. A description of the instrument and some preliminary results are given.

  17. Plasticity theory

    CERN Document Server

    Lubliner, Jacob

    2008-01-01

    The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

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

    Science.gov (United States)

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

    2015-05-01

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

  19. Systematic study of particle quenching in organic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, L.M.; Bagán, H. [Department of Analytical Chemistry of the University of Barcelona, Diagonal 645, E-08028 Barcelona (Spain); Tarancón, A., E-mail: alex.tarancon@ub.edu [Department of Analytical Chemistry of the University of Barcelona, Diagonal 645, E-08028 Barcelona (Spain); Rauret, G.; Garcia, J.F. [Department of Analytical Chemistry of the University of Barcelona, Diagonal 645, E-08028 Barcelona (Spain)

    2013-01-11

    Among the different factors that affect measurements by organic scintillators, the majority of attention has been focused on those related to the scintillator (i.e., ionization, chemical, color and optical quenching), and less attention has been paid to the loss of energy before the particle (i.e., alpha or beta) arrives at the scintillator (i.e., particle quenching). This study evaluates the effect of particle quenching in different scintillation methods (i.e., using two plastic scintillation microspheres (PSm1 and PSm2), liquid scintillator and gel scintillator) by measuring solutions that contain increasing concentrations of NaCl, BaCl{sub 2} and glycerin. The results show the importance of particle quenching in PSm measurements because detection efficiency decreases with increasing concentrations of the quenching component, although the spectrum position and external standard parameter remain constant. The results have shown evidence of particle quenching, although at a lower magnitude, in the liquid scintillation or gel scintillation measurements. Moreover, the use of two PSm with different diameters and salty compound that alters the equilibrium of the liquid and gel emulsions also exemplified the importance of the transmission of optical photons through different scintillation media (i.e., optical quenching). Improvement and deterioration of the optical conditions on the scintillation media is manifested as a movement of the spectrum to higher and lower energies, respectively. The results obtained with PSm were confirmed by Monte Carlo simulation.

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

    Science.gov (United States)

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

    2013-06-01

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

  1. Characterization of the scintillation anisotropy in crystalline stilbene scintillator detectors

    CERN Document Server

    Schuster, Patricia

    2016-01-01

    This paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline melt-grown and solution-grown stilbene to incident DT and DD neutrons. These measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature for melt-grown stilbene and providing the first measurements for solution-grown stilbene. In similar measurements of liquid and plastic detectors, no directional dependence was observed, confirming the hypothesis that the anisotropy in stilbene and other organic crystal scintillators is a result of internal effects due to the molecular or crystal structure and not an external effect on the measurement system.

  2. Scintillation response of organic and inorganic scintillators

    CERN Document Server

    Papadopoulos, L M

    1999-01-01

    A method to evaluate the scintillation response of organic and inorganic scintillators to different heavy ionizing particles is suggested. A function describing the rate of the energy consumed as fluorescence emission is derived, i.e., the differential response with respect to time. This function is then integrated for each ion and scintillator (anthracene, stilbene and CsI(Tl)) to determine scintillation response. The resulting scintillation responses are compared to the previously reported measured responses. Agreement to within 2.5% is observed when these data are normalized to each other. In addition, conclusions regarding the quenching parameter kB dependence on the type of the particle and the computed values of kB for certain ions are included. (author)

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

    Science.gov (United States)

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

    2015-01-01

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

  4. Fractionated resection on low grade gliomas involving Broca's area and insights to brain plasticity

    Institute of Scientific and Technical Information of China (English)

    WU Chen-xing; PU Song; LIN Yi; WANG Yong-zhi; JIANG Tao; XIE Jian; WEI Miao; YI Xiao-li; WANG Xiao-yi

    2008-01-01

    Background Resent advances on functional mapping have enabled us to conduct surgery on gliomas within the eloquent area. The objective of the article is to discuss the feasibility of a planned fractionated strategy of resection on low-grade gliomas (LGGs) involving Broca's area. We report the first surgical series of planned fractionated resections on LGGs within Broca's area, focusing on language functional reshaping.Methods Four patients were treated with fractionated operations for LGGs involving Broca's area. All cases underwent conventional magnetic resonance (MR) scanning, language functional MR and diffusion tensor imaging (DTI) before operation. The resections were then performed on patients under awake anesthesia using intraoperative electrical stimulation (IES) for functional mapping. Pre- and post-operative neuro-psychological examinations were evaluated. Results Total resections were achieved in all cases as confirmed by the postoperative control MR. After transient language worsening, all patients recovered to normal3-6 months later.Language functional MR scannings have shown the operation.All patients retumed to a normal socioprofessional life.Conclusions By utilizing the dynamic interaction between brain plasticity and fractionated resections,we can totally remove the tumor involving Broca'S structure without inducing permanent postoperative deficits and even improve the qualityof life.

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

    Directory of Open Access Journals (Sweden)

    Elena eVashchinkina

    2014-11-01

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

  6. Systematic studies of small scintillators for new sampling calorimeter

    Indian Academy of Sciences (India)

    E P Jacosalem; S Iba; N Nakajima; H Ono; A L C Sanchez; A M Bacala; H Miyata; GLD Calorimeter Group

    2007-12-01

    A new sampling calorimeter using very thin scintillators and the multi-pixel photon counter (MPPC) has been proposed to produce better position resolution for the international linear collider (ILC) experiment. As part of this R & D study, small plastic scintillators of different sizes, thickness and wrapping reflectors are systematically studied. The scintillation light due to beta rays from a collimated 90Sr source are collected from the scintillator by wavelength-shifting (WLS) fiber and converted into electrical signals at the PMT. The wrapped scintillator that gives the best light yield is determined by comparing the measured pulse height of each 10 × 40 × 2 mm strip scintillator covered with 3M reflective mirror film, teflon, white paint, black tape, gold, aluminum and white paint+teflon. The pulse height dependence on position, length and thickness of the 3M reflective mirror film and teflon wrapped scintillators are measured. Results show that the 3M radiant mirror film-wrapped scintillator has the greatest light yield with an average of 9.2 photoelectrons. It is observed that light yield slightly increases with scintillator length, but increases to about 100% when WLS fiber diameter is increased from 1.0 mm to 1.6 mm. The position dependence measurement along the strip scintillator showed the uniformity of light transmission from the sensor to the PMT. A dip across the strip is observed which is 40% of the maximum pulse height. The block type scintillator pulse height, on the other hand, is found to be almost proportional to scintillator thickness.

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

    Science.gov (United States)

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

    2014-03-15

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

  8. Light output of EJ228 scintillation neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Stevanato, L., E-mail: luca.stevanato@pd.infn.i [Dipartimento di Fisica dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); Fabris, D. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Hao, Xin [Dipartimento di Fisica dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); Lunardon, M.; Moretto, S. [Dipartimento di Fisica dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Nebbia, G.; Pesente, S. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Sajo-Bohus, L. [Universidad Simon-Bolivar, Laboratorio Fisica Nuclear, Apartado 8900, 1080 A. Caracas (Venezuela, Bolivarian Republic of); Viesti, G. [Dipartimento di Fisica dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy)

    2011-02-15

    The light output of neutron detectors based on the plastic scintillator EJ228 is studied as a function of neutron energy using a time tagged {sup 252}Cf source. Calibration of the light output scale is performed by fitting the experimental distribution of Compton scattering events of photons from a {sup 22}Na source with a response function obtained by Gaussian smearing of the predicted line-shape. The light output curve as well as the pulse height resolution for the EJ228 scintillators is very close (within 5%) to those recently reported for NE213 type organic liquid scintillators.

  9. Anticoincidence scintillation counter

    CERN Multimedia

    1966-01-01

    This anticoincidence scintillation counter will be mounted in a hydrogen target vessel to be used in a measurement of the .beta. parameter in the .LAMBDA0. decay. The geometry of the counter optimizes light collection in the central part where a scintillation disk of variable thickness can be fitted.

  10. Nonproportionality of inorganic scintillators

    NARCIS (Netherlands)

    Khodyuk, I.V.

    2013-01-01

    A scintillator is a transparent material that emits a flash of light when it absorbs a γ-ray photon or an energetic particle. Scintillation crystals are widely used as spectroscopic detectors of ionizing radiation in nuclear science, space exploration, medical imaging, homeland security, etc. This t

  11. Plastic Pollution at a Sea Turtle Conservation Area in NE Brazil: Contrasting Developed and Undeveloped Beaches.

    OpenAIRE

    Ivar do Sul, Juliana Assunção; Santos, Isaac Rodrigues dos; Friedrich, Ana Cláudia; Matthiensen, Alexandre; Fillmann, Gilberto

    2011-01-01

    Sea turtles are highly susceptible to plastic ingestion and entanglement. Beach debris were surveyed along the most important sea turtle nesting beaches in Brazil (Costa dos Coqueiros, Bahia State). No significant differences among developed and undeveloped beaches were observed in terms of total number of items. Local sources (tourism activities) represented 70% of debris on developed beaches, where cigarette butts, straws, paper fragments, soft plastic fragments, and food packaging...

  12. Performance comparison of scintillators for alpha particle detectors

    Science.gov (United States)

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

    2014-11-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  14. Pulse shape discrimination in non-aromatic plastics

    Energy Technology Data Exchange (ETDEWEB)

    Paul Martinez, H.; Pawelczak, Iwona; Glenn, Andrew M.; Leslie Carman, M.; Zaitseva, Natalia; Payne, Stephen

    2015-01-21

    Recently it has been demonstrated that plastic scintillators have the ability to distinguish neutrons from gamma rays by way of pulse shape discrimination (PSD). This discovery has lead to new materials and new capabilities. Here we report our work with the effects of aromatic, non-aromatic, and mixed aromatic/non-aromatic matrices have on the performance of PSD plastic scintillators.

  15. [Plastic surgery defect coverage in the area of the pelvis and trunk].

    Science.gov (United States)

    Germann, G; Erdmann, D; Sauerbier, M; Bickert, B

    1997-05-01

    Complex defects of the trunk and pelvic region are rare, but are mostly the sequelae of serious conditions. Stable soft tissue coverage after radical debridement of all avital tissue may be of vital importance for the patient. The article will demonstrate the options of plastic surgery procedures that should be known by the general surgeon to be eventually integrated into a interdisciplinary therapeutic concept.

  16. Neutron spectroscopy with scintillation detectors using wavelets

    Science.gov (United States)

    Hartman, Jessica

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

  17. Development of new Polysiloxane Based Liquid Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Palma, M.; Quaranta, A. [Department of Industrial Engineering, University of Trento,Via Sommarive, 9, 38123 Trento (Italy); INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Gramegna, F.; Marchi, T.; Cinausero, M. [INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Carturan, S.; Collazuol, G.; Checchia, C. [INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Department of Physics and Astronomy, University of Padova, Via Marzolo, 8, 35131 Padova (Italy); Degerlier, M. [Department of Physics, Nevsehir Haci Bektas Veli University, Science and Art Faculty, 50300 Nevsehir (Turkey)

    2015-07-01

    In the last decade, attention toward neutron detection has been growing in the scientific community, driven by new requirements in different fields of application ranging from homeland security to medical and material analysis, from research physics, to nuclear energy production. So far neutron detection, with particular attention to fast neutrons, has been mainly based on organic liquid scintillators, owing to their good efficiency and pulse shape discrimination (PSD) capability. Most of these liquids have however some main drawbacks given by toxicity, flammability, volatility and sensitivity to dissolved oxygen that limits the duration and the quality of their performances with worse handiness and increased costs. Phenyl-substituted polysiloxanes could address most of these issues, being characterized by low toxicity, low volatility and low flammability. Their optical properties can be tailored by changing the phenyl distribution and concentration thus allowing to increase the solubility of organic dyes, to modify the fluorescence spectra and to vary the refractive index of the medium. Furthermore, polysiloxanes have been recently exploited for the production of plastic scintillators with very good chemical and thermal stability and very good radiation hardness and the development of polysiloxane liquid scintillators could allow to combine these interesting properties with the supremacy of liquid scintillators as regarding PSD over plastics. For these reasons, the properties of several phenyl-substituted polysiloxane with different phenyl amounts and different viscosities have been investigated, with particular attention to the scintillation response and the pulse shape discrimination capability, and the results of the investigation are reported in this work. More in details, the scintillation light yield towards gamma rays ({sup 60}Co and {sup 137}Cs) of several polysiloxane liquids has been analyzed and compared with the light yield of a commercial non

  18. The response of a BGO scintillator to relativistic heavy ions

    CERN Document Server

    Matsufuji, N; Komami, H; Kohno, T

    1999-01-01

    The response of a BGO scintillator to He, C, Ne, Si and Ar ions has been studied at incident energies from 120 MeV up to 18 GeV for the first time. The energy of incident beam was changed by inserting an absorber of various thicknesses made of PMMA plates. The primary particles were identified and separated from projectile fragments by using the DELTA E-E counter telescope method. A thin NE102A plastic scintillator and a BGO scintillator were used as a DELTA E counter and a residual E detector, respectively. The energy of the primary particles was deduced by comparing the depth-dose distribution measured by an ionization chamber to those by a theoretical calculation. The light output of the BGO scintillator was found to be linear in this energy region. The dependency of the light output on the particle species was well indexed as a function of log (AZ sup 2).

  19. Scintillating properties of frozen new liquid scintillators

    CERN Document Server

    Britvich, G I; Golovkin, S V; Martellotti, G; Medvedkov, A M; Penso, G; Soloviev, A S; Vasilchenko, V G

    1999-01-01

    The light emission from scintillators which are liquid at room temperature was studied in the interval between $+20$~$^{\\circ}$C and $-120$~$^{\\circ}$C, where the phase transition from liquid to solid takes place. The light yield measured at $-120$~$^{\\circ}$C is about twice as much as that observed at $+20$~$^{\\circ}$C. By cooling the scintillator from $+20$~$^{\\circ}$C to $-120$~$^{\\circ}$C and then heating it from $-120$~$^{\\circ}$C to $+20$~$^{\\circ}$C, the light yield varies in steps at well defined temperatures, which are different for the cooling and heating processes. These hysteresis phenomena appear to be related to the solvent rather than to the dopant. The decay time of scintillation light was measured at $+20$~$^{\\circ}$C and $-120$~$^{\\circ}$C. Whilst at room temperature most of the light is emitted with a decay time of 6--8 ns, at $-120$~$^{\\circ}$C a slower component, with a decay time of 25--35 ns, becomes important.

  20. Influence of dissolved gas and temperature on the light yield of new liquid scintillators

    CERN Document Server

    Buontempo, S; Golovkin, S V; Martellotti, G; Medvedkov, A M; Penso, G; Soloviev, A S; Vasilchenko, V G

    1999-01-01

    Sixteen new liquid scintillators, emitting green light, were studied. They are based on four solvents combined with four dopants. The influence of different gas atmospheres was studied. In particular it was shown that by keeping these liquid scintillators in vacuum or in a neutral gas, the light yield increases up to 32~\\% at 20 $^{\\circ}$C and for the best solvent-dopant combinations. The dependance of the light yield on temperature was also studied for these scintillators. In the 20--60 $^{\\circ}$C interval, some exhibit a light yield variation of $\\sim$ 3 \\% which is smaller than that of the NE 102A plastic scintillator.

  1. Cross-Modal Plasticity Results in Increased Inhibition in Primary Auditory Cortical Areas

    Directory of Open Access Journals (Sweden)

    Yu-Ting Mao

    2013-01-01

    Full Text Available Loss of sensory input from peripheral organ damage, sensory deprivation, or brain damage can result in adaptive or maladaptive changes in sensory cortex. In previous research, we found that auditory cortical tuning and tonotopy were impaired by cross-modal invasion of visual inputs. Sensory deprivation is typically associated with a loss of inhibition. To determine whether inhibitory plasticity is responsible for this process, we measured pre- and postsynaptic changes in inhibitory connectivity in ferret auditory cortex (AC after cross-modal plasticity. We found that blocking GABAA receptors increased responsiveness and broadened sound frequency tuning in the cross-modal group more than in the normal group. Furthermore, expression levels of glutamic acid decarboxylase (GAD protein were increased in the cross-modal group. We also found that blocking inhibition unmasked visual responses of some auditory neurons in cross-modal AC. Overall, our data suggest a role for increased inhibition in reducing the effectiveness of the abnormal visual inputs and argue that decreased inhibition is not responsible for compromised auditory cortical function after cross-modal invasion. Our findings imply that inhibitory plasticity may play a role in reorganizing sensory cortex after cross-modal invasion, suggesting clinical strategies for recovery after brain injury or sensory deprivation.

  2. Photodetectors for scintillator proportionality measurement

    Energy Technology Data Exchange (ETDEWEB)

    Moses, William W. [Lawrence Berkeley National Laboratory (United States)], E-mail: wwmoses@lbl.gov; Choong, Woon-Seng [Lawrence Berkeley National Laboratory (United States); Hull, Giulia; Payne, Steve; Cherepy, Nerine; Valentine, John D. [Lawrence Livermore National Laboratory (United States)

    2009-10-21

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

  3. Scintillator Measurements for SNO+

    Science.gov (United States)

    Kaptanoglu, Tanner; SNO+ Collaboration

    2016-03-01

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

  4. Delta-opioid receptors mediate unique plasticity onto parvalbumin-expressing interneurons in area CA2 of the hippocampus.

    Science.gov (United States)

    Piskorowski, Rebecca A; Chevaleyre, Vivien

    2013-09-04

    Inhibition is critical for controlling information transfer in the brain. However, the understanding of the plasticity and particular function of different interneuron subtypes is just emerging. Using acute hippocampal slices prepared from adult mice, we report that in area CA2 of the hippocampus, a powerful inhibitory transmission is acting as a gate to prevent CA3 inputs from driving CA2 neurons. Furthermore, this inhibition is highly plastic, and undergoes a long-term depression following high-frequency 10 Hz or theta-burst induction protocols. We describe a novel form of long-term depression at parvalbumin-expressing (PV+) interneuron synapses that is dependent on delta-opioid receptor (DOR) activation. Additionally, PV+ interneuron transmission is persistently depressed by DOR activation in area CA2 but only transiently depressed in area CA1. These results provide evidence for a differential temporal modulation of PV+ synapses between two adjacent cortical circuits, and highlight a new function of PV+ cells in controlling information transfer.

  5. Microfluidic Scintillation Detectors

    CERN Multimedia

    Microfluidic scintillation detectors are devices of recent introduction for the detection of high energy particles, developed within the EP-DT group at CERN. Most of the interest for such technology comes from the use of liquid scintillators, which entails the possibility of changing the active material in the detector, leading to an increased radiation resistance. This feature, together with the high spatial resolution and low thickness deriving from the microfabrication techniques used to manufacture such devices, is desirable not only in instrumentation for high energy physics experiments but also in medical detectors such as beam monitors for hadron therapy.

  6. Scintillation spectroscopy for beta ray dose measurements

    Energy Technology Data Exchange (ETDEWEB)

    Vapirev, E.I.; Jordanov, T.; Amin, S.; Stoilov, N.; Georgieva, K. [Sofia Univ. (Bulgaria). Fizicheski Fakultet

    1996-11-01

    Two methods have been developed and tested for the measurement of beta ray dose with a scintillation probe. According to the first method the energy absorbed in plastic filters is calculated from the difference between the energy E of the incident and filtered beta spectrum with an expression of the type E {approx} c{Sigma}iN(i)/{Delta}m, where c is a calibration constant (keV per channel), i is the channel number, N(i) is the detected beta spectrum, and {Delta}m is the filter thickness. According to the second `dE/dx` method the energy deposited in the surface layer of the scintillator is calculated by E {approx} c{Sigma}dE/dx(i)N(i), where dE/dx is the specific energy loss for tissue-equivalent media. The methods were tested for the cases of normally incident electrons and surface contamination. The scintillation probe used is stillbene and the test sources are thin {sup 90}Sr/{sup 90}Y and {sup 137}Cs. The results are close to the expected doses as calculated by Monte Carlo simulations. (Author).

  7. Smoking and alcoholism target genes associated with plasticity and glutamate transmission in the human ventral tegmental area.

    Science.gov (United States)

    Flatscher-Bader, T; Zuvela, N; Landis, N; Wilce, P A

    2008-01-01

    Drugs of abuse including nicotine and alcohol elicit their effect by stimulating the mesocorticolimbic dopaminergic system. There is a high incidence of nicotine dependence in alcoholics. To date only limited data is available on the molecular mechanism underlying the action of alcohol and nicotine in the human brain. This study utilized gene expression screening to identify genes sensitive to chronic alcohol abuse within the ventral tegmental area (VTA) of the human brain. Alcohol-responsive genes encoded proteins primarily involved in structural plasticity and neurotransmitter transport and release. In particular, genes involved with brain-derived neurotrophic factor signalling and glutamatergic transmission were found to be affected. The possibility that glutamate transport was a target of chronic alcohol and/or tobacco abuse was further investigated in an extended case set by measurement of mRNA and protein expression. Expression levels of vesicular glutamate transporters SLC17A6 and SLC17A7 were robustly induced by smoking, an effect that was reduced by alcohol co-exposure. Glutamatergic transmission is vital for the control of the VTA and may also be critical to the weighting of novelty and importance of a stimulus, an essential output of this brain region. We conclude that enduring plasticity within the VTA may be a major molecular mechanism for the maintenance of smoking addiction and that alcohol, nicotine and co-abuse have distinct impacts on glutamatergic transmission with important implications for the control of this core mesolimbic structure.

  8. Organic scintillators with pulse shape discrimination for detection of radiation (Conference Presentation)

    Science.gov (United States)

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

    2016-09-01

    The detection of neutrons in the presence of gamma-ray fields has important applications in the fields of nuclear physics, homeland security, and medical imaging. Organic scintillators provide several attractive qualities as neutron detection materials including low cost, fast response times, ease of scaling, and the ability to implement pulse shape discrimination (PSD) to discriminate between neutrons and gamma-rays. This talk will focus on amorphous organic scintillators both in plastic form and small-molecule organic glass form. The first section of this talk will describe recent advances and improvements in the performance of PSD-capable plastic scintillators. The primary advances described in regard to modification of the polymer matrix, evaluation of new scintillating dyes, improved fabrication conditions, and implementation of additives which impart superior performance and mechanical properties to PSD-capable plastics as compared to commercially-available plastics and performance comparable to PSD-capable liquids. The second section of this talk will focus on a class of small-molecule organic scintillators based on modified indoles and oligophenylenes which form amorphous glasses as PSD-capable neutron scintillation materials. Though indoles and oligophenylenes have been known for many decades, their PSD properties have not been investigated and their scintillation properties only scantily investigated. Well-developed synthetic methodologies have permitted the synthesis of a library of structural analogs of these compounds as well as the investigation of their scintillation properties. The emission wavelengths of many indoles are in the sensitive region of common photomultiplier tubes, making them appropriate to be used as scintillators in either pure or doped form. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This work has been supported by the U

  9. X-ray Scintillation in Lead Halide Perovskite Crystals

    OpenAIRE

    Birowosuto, M. D.; Cortecchia, D.; Drozdowski, W.; K. Brylew; Łachmański, W.; A. Bruno; Soci, C.

    2016-01-01

    Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to the presence of heavy atoms, solution-grown hybrid lead halide perovskite single crystals exhibit short X-ray absorption length and excellent detection efficiency. Here we compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional (2D) (...

  10. Performance of the CHORUS lead-scintillating fiber calorimeter

    CERN Document Server

    Buontempo, S

    1997-01-01

    We report on the design and performance of the lead-scintillating fiber calorimeter of the CHORUS experiment, which searches for νμ-ντ oscillations in the CERN Wide Band Neutrino beam. Two of the three sectors in which the calorimeter is divided are made of lead and plastic scintillating fibers, and they represent the first large scale application of this technique for combined electromagnetic and hadronic calorimetry. The third sector is built using the sandwich technique with lead plates and scintillator strips and acts as a tail catcher for the hadronic energy flow. From tests performed at the CERN SPS and PS an energy resolution of σ(E)/E=(32.3±2.4)%/E(GeV)+(1.4±0.7)% was measured for pions, and σ(E)/E=(13.8±0.9)%/E(GeV)+(−0.2±0.4)% for electrons.

  11. Detecting alpha radiation by scintillation in porous materials

    Energy Technology Data Exchange (ETDEWEB)

    Keillor, M.E. [McClellan Central Lab., McClellan AFB, CA (United States); Burggraf, L.W. [Air Force Inst. of Tech., Wright-Patterson AFB, OH (United States)

    1997-10-01

    This paper presents a study of some parameters essential to the development of a heterogeneous scintillation detector with improved alpha energy resolution and detection efficiency. Such a detector with better than 10% alpha energy resolution could provide in situ capability to identify and quantify important alpha-emitting radionuclides in dilute aqueous solutions. Nanoporous gel-silica is a potential scintillation matrix with the promise of improved energy resolution and 100% detection efficiency. Scintillating gel-silica made by a sol-gel process is under development. As a step toward realizing the system described, the dependence of alpha detection efficiency and intrinsic energy resolution in particulate and porous glass scintillation detectors is examined. The two main areas of this research are: (1) computer modeling of the geometric detection efficiency and energy dispersion in particulate and porous glass scintillation detectors and (2) experiments to test model predictions for detection of alphas in liquid-infiltrated porous glass structures. To confirm the predicted alpha energy deposition, the authors measured scintillation in nanoporous gel-silica infiltrated with an organic liquid scintillator. Results show that phase dimensions must be considered in constructing a heterogeneous detector for alpha spectroscopy. Nanometer-scale dimensions available in gel-silica essentially eliminate degradation of energy resolution due to energy dispersion of alpha particles within the liquid sample, while providing 100% detection efficiency.

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

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Joseph S.; Feng, Patrick L., E-mail: plfeng@sandia.gov

    2016-10-01

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

  13. Fast scintillation timing detector using proportional-mode avalanche photodiode for nuclear resonant scattering experiments in high-energy synchrotron X-ray region

    Science.gov (United States)

    Inoue, Keisuke; Kishimoto, Shunji

    2016-01-01

    To obtain both a high count rate of >107 s-1 and a detection efficiency sufficient for high-energy X-rays of >30 keV, we propose a scintillation timing detector using a proportional-mode silicon avalanche photodiode (Si-APD) for synchrotron radiation nuclear resonant scattering. We here present results obtained with a prototype detector using a lead-loaded plastic scintillator (EJ-256) mounted on a proportional-mode Si-APD (active area size: 3 mm in diameter). The detector was operated at ‒35 °C for a better signal-to-noise ratio. Using synchrotron X-rays of 67.41 keV, which is the same energy as the first excited level of 61Ni, we successfully measured pulse-height and time spectra of the scintillation light. A good time resolution of 0.50±0.06 ns (full width at half-maximum) was obtained for 67.41 keV X-rays with a scintillator 3 mm in diameter and 2 mm thick.

  14. Performance of the first prototype of the CALICE scintillator strip electromagnetic calorimeter

    CERN Document Server

    Francis, K.; Schlereth, J.; Smith, J.; Xia, L.; Baldolemar, E.; Li, J.; Park, S.T.; Sosebee, M.; White, A.P.; Yu, J.; Eigen, G.; Mikami, Y.; Watson, N.K.; Thomson, M.A.; Ward, D.R.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Dotti, A.; Folger, G.; Ivantchenko, V.; Ribon, A.; Uzhinskiy, V.; Carloganu, C.; Gay, P.; Manen, S.; Royer, L.; Tytgat, M.; Zaganidis, N.; Blazey, G.C.; Dyshkant, A.; Lima, J.G.R.; Zutshi, V.; Hostachy, J. -Y.; Morin, L.; Cornett, U.; David, D.; Ebrahimi, A.; Falley, G.; Gadow, K.; Goettlicher, P.; Guenter, C.; Hartbrich, O.; Hermberg, B.; Karstensen, S.; Krivan, F.; Krueger, K.; Lutz, B.; Morozov, S.; Morgunov, V.; Neubueser, C.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Garutti, E.; Laurien, S.; Lu, S.; Marchesini, I.; Matysek, M.; Ramilli, M.; Briggl, K.; Eckert, P.; Harion, T.; Schultz-Coulon, H. -Ch.; Shen, W.; Stamen, R.; Bilki, B.; Norbeck, E.; Northacker, D.; Onel, Y.; Wilson, G.W.; Kawagoe, K.; Sudo, Y.; Yoshioka, T.; Dauncey, P.D.; Wing, M.; Salvatore, F.; Cortina Gil, E.; Mannai, S.; Baulieu, G.; Calabria, P.; Caponetto, L.; Combaret, C.; Della Negra, R.; Grenier, G.; Han, R.; Ianigro, J-C.; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Petrukhin, A.; Steen, A.; Tromeur, W.; Vander donckt, M.; Zoccarato, Y.; Calvo Alamillo, E.; Fouz, M.-C.; Puerta-Pelayo, J.; Corriveau, F.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Popov, V.; Rusinov, V.; Tarkovsky, E.; Besson, D.; Buzhan, P.; Ilyin, A.; Kantserov, V.; Kaplin, V.; Karakash, A.; Popova, E.; Tikhomirov, V.; Kiesling, C.; Seidel, K.; Simon, F.; Soldner, C.; Weuste, L.; Amjad, M.S.; Bonis, J.; Callier, S.; Conforti di Lorenzo, S.; Cornebise, P.; Doublet, Ph.; Dulucq, F.; Fleury, J.; Frisson, T.; van der Kolk, N.; Li, H.; Martin-Chassard, G.; Richard, F.; de la Taille, Ch.; Poeschl, R.; Raux, L.; Rouene, J.; Seguin-Moreau, N.; Anduze, M.; Balagura, V.; Boudry, V.; Brient, J-C.; Cornat, R.; Frotin, M.; Gastaldi, F.; Guliyev, E.; Haddad, Y.; Magniette, F.; Musat, G.; Ruan, M.; Tran, T.H.; Videau, H.; Bulanek, B.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Belhorma, B.; Ghazlane, H.; Kotera, K.; Ono, H.; Takeshita, T.; Uozumi, S.; Jeans, D.; Chang, S.; Khan, A.; Kim, D.H.; Kong, D.J.; Oh, Y.D.; Goetze, M.; Sauer, J.; Weber, S.; Zeitnitz, C.

    2014-01-01

    A first prototype of a scintillator strip-based electromagnetic calorimeter was built, consisting of 26 layers of tungsten absorber plates interleaved with planes of 45x10x3 mm3 plastic scintillator strips. Data were collected using a positron test beam at DESY with momenta between 1 and 6 GeV/c. The prototype's performance is presented in terms of the linearity and resolution of the energy measurement. These results represent an important milestone in the development of highly granular calorimeters using scintillator strip technology. This technology is being developed for a future linear collider experiment, aiming at the precise measurement of jet energies using particle flow techniques.

  15. Study of micro pixel photon counters for a high granularity scintillator-based hadron calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    D' Ascenzo, N. [Hamburg Univ. (Germany)]|[Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Eggemann, A.; Garutti, E. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2007-11-15

    A new Geiger mode avalanche photodiode, the Micro Pixel Photon Counter (MPPC), was recently released by Hamamatsu. It has a high photo-detection efficiency in the 420 nm spectral region. This product can represent an elegant candidate for the design of a high granularity scintillator based hadron calorimeter for the International Linear Collider. In fact, the direct readout of the blue scintillation photons with a MPPC is a feasible techological solution. The readout of a plastic scintillator by a MPPC, both mediated by the traditional wavelength shifting fiber, and directly coupled, has been systematically studied. (orig.)

  16. A design of scintillator tiles read out by surface-mounted SiPMs for a future hadron calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong; Bauss, Bruno; Buescher, Volker; Caudron, Julien; Chau, Phi; Degele, Reinhold; Geib, Karl-Heinrich; Masetti, Lucia; Schaefer, Ulrich; Tapprogge, Stefan; Wanke, Rainer [Institut fuer Physik and PRISMA Detector Lab, Johannes Gutenberg-Universitaet Mainz (Germany)

    2015-07-01

    Precision calorimetry using highly granular sampling calorimeters is being developed based on the particle flow concept within the CALICE collaboration. One design option of a hadron calorimeter is based on silicon photomultipliers (SiPMs) to detect photons generated in plastic scintillator tiles. Driven by the need of automated mass assembly of around ten millions of channels stringently required by the high granularity, we developed a design of scintillator tiles directly coupled with surface-mounted SiPMs. A cavity is created in the center of the bottom surface of each tile to provide enough room for the whole SiPM package and to improve collection of the light produced by incident particles penetrating the tile at different positions. The cavity design has been optimized using a GEANT4-based full simulation model to achieve high response to Minimum Ionizing Particles (MIPs) and also good areal uniformity. Cosmic-ray measurements confirms high 1-MIP response for scintillator tiles with an optimized cavity design. Uniformity measurements by scanning the tile area using focused electrons from a beta source show excellent response uniformity. This optimized design is well beyond the requirements for a precision hadron calorimeter.

  17. GPS Scintillation Analysis.

    Science.gov (United States)

    2007-11-02

    Rev. 2-89) Prescribed by ANSI Std. Z39-1 298-102 TABLE OF CONTENTS 1. INTRODUCTION 1 2. GPS COMPARISON WITH ALL-SKY IMAGES OVER AGUA VERDE...Depletions from 1 October 1994 2 3. GPS data from Agua Verde, Chile on the night of 1 October 1994 3 4. PL-SCINDA display of GPS ionospheric...comparison of GPS measurements with GOES8 L-band scintillation data, are discussed. 2. GPS COMPARISON WITH ALL-SKY IMAGES OVER AGUA VERDE, CHILE As

  18. Scintillating fiber detector

    CERN Document Server

    Vozak, Matous

    2016-01-01

    NA61 is one of the physics experiments at CERN dedicated to study hadron states coming from interactions of SPS beams with various targets. To determine the position of a secondary beam, three proportional chambers are placed along the beamline. However, these chambers tend to have slow response. In order to obtain more precise time information, use of another detector is being considered. Fast response and compact size is making scintillation fiber (SciFi) with silicon photomultiplier (Si-PM) read out a good candidate. This report is focused on analysing data from SciFi collected in a test beam at the beginning of July 2016.

  19. Photonic Crystals: Enhancing the Light Output of Scintillation Based Detectors

    CERN Document Server

    Knapitsch, Arno Richard

    A scintillator is a material which emits light when excited by ionizing radiation. Such materials are used in a diverse range of applications; From high energy particle physics experiments, X-ray security, to nuclear cameras or positron emission tomography. Future high-energy physics (HEP) experiments as well as next generation medical imaging applications are more and more pushing towards better scintillation characteristics. One of the problems in heavy scintillating materials is related to their high index of refraction. As a consequence, most of the scintillation light produced in the bulk material is trapped inside the crystal due to total internal reflection. The same problem also occurs with light emitting diodes (LEDs) and has for a long time been considered as a limiting factor for their overall efficiency. Recent developments in the area of nanophotonics were showing now that those limitations can be overcome by introducing a photonic crystal (PhC) slab at the outcoupling surface of the substrate. P...

  20. Development of Radiation Hard Scintillators

    CERN Document Server

    Tiras, Emrah; Bilki, Burak; Winn, David; Onel, Yasar

    2016-01-01

    Modern high-energy physics experiments are in ever increasing need for radiation hard scintillators and detectors. In this regard, we have studied various radiation-hard scintillating materials such as Polyethylene Naphthalate (PEN), Polyethylene Terephthalate (PET), our prototype material Scintillator X (SX) and Eljen (EJ). Scintillation and transmission properties of these scintillators are studied using stimulated emission from a 334 nm wavelength UV laser with PMT before and after certain amount of radiation exposure. Recovery from radiation damage is studied over time. While the primary goal of this study is geared for LHC detector upgrades, these new technologies could easily be used for future experiments such as the FCC and ILC. Here we discuss the physics motivation, recent developments and laboratory measurements of these materials.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    1986-01-01

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

  3. Fast Scintillating Paddles for DarkLight

    Science.gov (United States)

    Palumbo, Daniel

    2017-01-01

    The DarkLight experiment proposes to search for a dark photon in the 10-100 MeV mass range via its production in fixed-target electron-proton collisions. The experimental design is driven by the desire to detect the complete final state including the recoiling proton, while also sustaining a very high luminosity in order to search for this rare process. Although the final design of the DarkLight experiment calls for fully streamed detector readout, initial studies will rely on traditional, triggered approaches. In order to facilitate precision measurements at high rate, a fast, thin, finely-segmented trigger detector based on plastic scintillating paddles and custom amplifiers was developed. I will discuss this design and its performance in recent DarkLight beam studies, as well as the work we have done to develop detectors using individual scintillating fibers. The DarkLight project is supported by DOE grant DE-FG02-94ER40818.

  4. Plastic Surgery

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Plastic Surgery KidsHealth > For Teens > Plastic Surgery Print A A ... forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word "plastic" ...

  5. Fracture-resistant lanthanide scintillators

    Science.gov (United States)

    Doty, F. Patrick

    2011-01-04

    Lanthanide halide alloys have recently enabled scintillating gamma ray spectrometers comparable to room temperature semiconductors (lanthanide alloy substitution, while preserving scintillation, have been demonstrated. Isovalent alloys having nominal compositions of comprising Al, Ga, Sc, Y, and In dopants as well as aliovalent alloys comprising Ca, Sr, Zr, Hf, Zn, and Pb dopants were prepared. All of these alloys exhibit bright fluorescence under UV excitation, with varying shifts in the spectral peaks and intensities relative to pure CeBr.sub.3. Further, these alloys scintillate when coupled to a photomultiplier tube (PMT) and exposed to .sup.137Cs gamma rays.

  6. The balloon-borne electron telescope with scintillating fibers (BETS)

    CERN Document Server

    Torii, S; Tateyama, N; Yoshida, K; Ouchi, Y; Yamagami, T; Saitô, Y; Murakami, H; Kobayashi, T; Komori, Y; Kasahara, K; Yuda, T; Nishimura, J

    2000-01-01

    we describe a new detector system developed for high-altitude balloon flights to observe the cosmic-ray electrons above 10 GeV. The balloon borne electron telescope with Scintillating (BETS) fibers instrument is an imaging calorimeter which is capable of selecting electrons against the large background of protons. The calorimeter is composed of a sandwich of scintillating optical-fiber belts and lead plates with a combination of three plastic scintillators for the shower trigger. The total thickness of lead is 40 mm (~7.1 r.l.) and the number of fiber belts is nine. In each belt, alternating layers are oriented in orthogonal (x and y) directions. Two sets of an intensified CCD camera are adopted for read-out of the scintillating fibers in the x and y direction, respectively. The accelerator beam tests were carried out to study the performance of detector for electrons in 1996 and for protons in 1997 at CERN-SPS. The instrument was successfully flown aboard high-altitude balloon in 1997 and 1998. It is demonst...

  7. Extracellular signal-regulated kinase (ERK) signaling in the ventral tegmental area mediates cocaine-induced synaptic plasticity and rewarding effects

    OpenAIRE

    Pan, Bin; Zhong, Peng; Sun, Dalong; Liu, Qing-song

    2011-01-01

    Drugs of abuse such as cocaine induce long-term synaptic plasticity in the reward circuitry, which underlies the formation of drug-associated memories and addictive behavior. We reported previously that repeated cocaine exposure in vivo facilitates long-term potentiation in dopamine neurons of the ventral tegmental area (VTA) by reducing the strength of GABAergic inhibition and that endocannabinoid (eCB)-dependent long-term depression at inhibitory synapses (I-LTD) constitutes a mechanism for...

  8. Ionospheric Scintillation Effects on GPS

    Science.gov (United States)

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

    2007-12-01

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

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

    Science.gov (United States)

    Link, Jason

    2011-01-01

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

  10. Direct Coupling of SiPMs to Scintillator Tiles for Imaging Calorimetry and Triggering

    CERN Document Server

    Simon, Frank; Joram, Christian

    2010-01-01

    The recent availability of blue sensitive silicon photomultipliers allows the direct readout of blue emitting plastic scintillator tiles without the use of a wavelength shifting fiber. Such directly read out tiles, without light guides, are attractive for the use in highly granular calorimeters that use large numbers of individual cells and in other applications where very compact designs are needed. However, the total signal amplitude and the uniformity of the response can be problematic in such cases. We have developed a scanning setup to investigate the response of scintillator tiles with SiPM readout in detail. It was used to develop optimized scintillator tile geometries for highly granular hadronic calorimetry at future colliders and to investigate the feasibility of a SiPM readout for the trigger of the ATLAS ALFA luminosity detectors. We report on results obtained with specialized scintillator tile geometries, discuss first results obtained with directly coupled SiPM readout of the ATLAS ALFA trigger ...

  11. Intuitive model for the scintillations of a partially coherent beam.

    Science.gov (United States)

    Efimov, Anatoly

    2014-12-29

    An intuitive model for the scintillation index of a partially coherent beam is developed in which essentially the only critical parameter is the properly defined Fresnel number equal to the ratio of the "working" aperture area to the area of the Fresnel zone. The model transpired from and is supported by numerical simulations using Rytov method for weak fluctuations regime and Tatarskii turbulence spectrum with inner scale. The ratio of the scintillation index of a partially coherent beam to that of a plane wave displays a characteristic minimum, the magnitude of which and its distance from the transmitter are easily explained using the intuitive model. A theoretical asymptotic is found for the scintillation index of a source with decreasing coherence at this minimum.

  12. The Ionospheric Scintillation Effects on the BeiDou Signal Receiver

    Directory of Open Access Journals (Sweden)

    Zhijun He

    2016-11-01

    Full Text Available Irregularities in the Earth’s ionosphere can make the amplitude and phase of radio signals fluctuate rapidly, which is known as ionospheric scintillation. Severe ionospheric scintillation could affect the performance of the Global Navigation Satellite System (GNSS. Currently, the Multiple Phase Screen (MPS technique is widely used in solving problems caused by weak and strong scintillations. Considering that Southern China is mainly located in the area where moderate and intense scintillation occur frequently, this paper built a model based on the MPS technique and discussed the scintillation impacts on China’s BeiDou navigation system. By using the BeiDou B1I signal, this paper analyzed the scintillation effects on the receiver, which includes the acquisition and tracking process. For acquisition process, this paper focused on the correlation peak and acquisition probability. For the tracking process, this paper focused on the carrier tracking loop and the code tracking loop. Simulation results show that under high scintillation intensity, the phase fluctuation could be −1.13 ± 0.087 rad to 1.40 ± 0.087 rad and the relative amplitude fluctuation could be −10 dB to 8 dB. As the scintillation intensity increased, the average correlation peak would decrease more than 8%, which could thus degrade acquisition performance. On the other hand, when the signal-to-noise ratio (SNR is comparatively lower, the influence of strong scintillation on the phase locked loop (PLL is much higher than that of weak scintillation. As the scintillation becomes more intense, PLL variance could consequently results in an error of more than 2.02 cm in carrier-phase based ranging. In addition, the delay locked loop (DLL simulation results indicated that the pseudo-range error caused by strong scintillation could be more than 4 m and the consequent impact on positioning accuracy could be more than 6 m.

  13. The Ionospheric Scintillation Effects on the BeiDou Signal Receiver.

    Science.gov (United States)

    He, Zhijun; Zhao, Hongbo; Feng, Wenquan

    2016-11-09

    Irregularities in the Earth's ionosphere can make the amplitude and phase of radio signals fluctuate rapidly, which is known as ionospheric scintillation. Severe ionospheric scintillation could affect the performance of the Global Navigation Satellite System (GNSS). Currently, the Multiple Phase Screen (MPS) technique is widely used in solving problems caused by weak and strong scintillations. Considering that Southern China is mainly located in the area where moderate and intense scintillation occur frequently, this paper built a model based on the MPS technique and discussed the scintillation impacts on China's BeiDou navigation system. By using the BeiDou B1I signal, this paper analyzed the scintillation effects on the receiver, which includes the acquisition and tracking process. For acquisition process, this paper focused on the correlation peak and acquisition probability. For the tracking process, this paper focused on the carrier tracking loop and the code tracking loop. Simulation results show that under high scintillation intensity, the phase fluctuation could be -1.13 ± 0.087 rad to 1.40 ± 0.087 rad and the relative amplitude fluctuation could be -10 dB to 8 dB. As the scintillation intensity increased, the average correlation peak would decrease more than 8%, which could thus degrade acquisition performance. On the other hand, when the signal-to-noise ratio (SNR) is comparatively lower, the influence of strong scintillation on the phase locked loop (PLL) is much higher than that of weak scintillation. As the scintillation becomes more intense, PLL variance could consequently results in an error of more than 2.02 cm in carrier-phase based ranging. In addition, the delay locked loop (DLL) simulation results indicated that the pseudo-range error caused by strong scintillation could be more than 4 m and the consequent impact on positioning accuracy could be more than 6 m.

  14. Structural and thermal properties of the Poly(styrene-ethyl acrylate) polymeric scintillation material for surface radioactive contamination measurement

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ho Sang; Seo, Bum Kyoung; Lee, Kune Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-10-15

    Emulsion polymerization is a unique chemical process widely used to produce waterborne resins with various colloidal and physicochemical properties. These emulsion polymers find a wide range of applications such as synthetic rubbers, thermoplastics, coatings, adhesives, binders, rheological modifiers, plastics pigments, standards for the calibration of instruments, polymeric supports for the purification of proteins and drug delivery system, etc. Polystyrenes are widely employed as matrices in order to dope scintillating dyes for alpha and beta radiation sensors. For example, BC-400 (Bicron Direct Saint-Gobain, MA), a polyvinyltoluene-based scintillator doped with PPO and POPOP, is the best existing plastic scintillator for alpha particle detection. Using emulsion polymerization technique described in a previous communication, experiments have been performed to investigate the detection performance with the scintillators contents. In this paper, the properties of the polymer for radioactive contaminant measurement observed under various condition of polymerization and variously EA contents.

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

    Science.gov (United States)

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

    2015-03-01

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

  16. Progress report for the scintillator plate calorimeter subsystem

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    This report covers the work completed in FY90 by ANL staff and those of Westinghouse STC and BICRON Corporation under subcontract to ANL towards the design of a compensating calorimeter based on the use of scintillator plate as the sensitive medium. It is presented as five task sections dealing with respectively mechanical design; simulation studies; optical system design; electronics development; development of rad hard plastic scintillator and wavelength shifter and a summary. The work carried out by the University of Tennessee under a subcontract from ANL is reported separately. Finally, as principal institution with responsibility for the overall management of this subsystem effort, the summary here reports the conclusions resulting from the work of the collaboration and their impact on our proposed direction of effort in FY91. This proposal, for obvious reasons is given separately.

  17. Tungsten Scintillating Fibers Electromagnetic Calorimeters for sPHENIX upgrade

    Science.gov (United States)

    Li, Siyang; Loggins, Vera; Phipps, Michael; Sickles, Anne

    2015-10-01

    sPHENIX, a planned new detector at RHIC, features electromagnetic and hadronic calorimetry that covers | η| design is optimized for the study of jets in heavy ion collisions. The design includes a tungsten fiber EmCal that is made out of a tower array of plastic scintillating fiber embedded inside a mixture of tungsten powder and epoxy. For this calorimeter, silicon photomultipliers will be attached at the end of the module to convert scintillated optical photons into electrical signals. The sPHENIX group at Illinois is currently making samples of these modules to study the production process and achievable density. In addition, we have set up a silicon photomultiplier read out test system which will be used to evaluate the module performance. sPHENIX collaboration and Brookhaven National Laboratory.

  18. Challenges in plastics recycling

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Jakobsen, L. G.; Eriksen, Marie Kampmann

    2015-01-01

    Recycling of waste plastics still remains a challenging area in the waste management sector. The current and potential goals proposed on EU or regional levels are difficult to achieve, and even to partially fullfil them the improvements in collection and sorting should be considerable. A study...... was undertaken to investigate the factors affecting quality in plastics recycling. The preliminary results showed factors primarily influencing quality of plastics recycling to be polymer cross contamination, presence of additives, non-polymer impurities, and polymer degradation. Deprivation of plastics quality......, with respect to recycling, has been shown to happen throughout the plastics value chain, but steps where improvements may happen have been preliminary identified. Example of Cr in plastic samples analysed showed potential spreading and accumulation of chemicals ending up in the waste plastics. In order...

  19. Cherenkov and Scintillation Light Separation in Organic Liquid Scintillators

    CERN Document Server

    Caravaca, J; Land, B J; Yeh, M; Gann, G D Orebi

    2016-01-01

    The CHErenkov / Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2g/L of PPO as a fluor (LAB/PPO). This is the first such demonstration for the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 +/- 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 +/- 3% and 63 +/- 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 +/- 5% and 38 +/- 4%. LAB/PPO data is consistent with a rise time of 0.75 +/- 0.25 ns.

  20. GPS scintillations and total electron content climatology in the southern low, middle and high latitude regions

    Directory of Open Access Journals (Sweden)

    Luca Spogli

    2013-06-01

    Full Text Available In recent years, several groups have installed high-frequency sampling receivers in the southern middle and high latitude regions, to monitor ionospheric scintillations and the total electron content (TEC changes. Taking advantage of the archive of continuous and systematic observations of the ionosphere on L-band by means of signals from the Global Positioning System (GPS, we present the first attempt at ionospheric scintillation and TEC mapping from Latin America to Antarctica. The climatology of the area considered is derived through Ground-Based Scintillation Climatology, a method that can identify ionospheric sectors in which scintillations are more likely to occur. This study also introduces the novel ionospheric scintillation 'hot-spot' analysis. This analysis first identifies the crucial areas of the ionosphere in terms of enhanced probability of scintillation occurrence, and then it studies the seasonal variation of the main scintillation and TEC-related parameters. The results produced by this sophisticated analysis give significant indications of the spatial/ temporal recurrences of plasma irregularities, which contributes to the extending of current knowledge of the mechanisms that cause scintillations, and consequently to the development of efficient tools to forecast space-weather-related ionospheric events.

  1. New halide scintillators for gamma ray detection

    NARCIS (Netherlands)

    Alekhin, M. S.

    2013-01-01

    Scintillators are used for the detection of ionizing radiation. Despite decades of intensive search and numerous compounds discovered, there is still a need for materials with improved properties. Recently, several new scintillators with excellent light yield, energy resolution, and proportionality

  2. Radiopure Metal-Loaded Liquid Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Rosero, Richard [Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Dept.; Yeh, Minfang [Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Dept.

    2015-03-18

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

  3. Performance of Large Neutron Detectors Containing Lithium-Gadolinium-Borate Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, David M.; Stuart, Cory R.; Klaass, R. Fred; Merrill, David B. [MSI/Photogenics Division, Orem, Utah (United States)

    2015-07-01

    This paper describes the development and testing of a neutron counter, spectrometer, and dosimeter that is compact, efficient, and accurate. A self-contained neutron detection instrument has wide applications in health physics, scientific research, and programs to detect, monitor, and control strategic nuclear materials (SNM). The 1.3 liter detector head for this instrument is a composite detector with an organic scintillator containing uniformly distributed {sup 6}Li{sub 6}{sup nat}Gd{sup 10}B{sub 3}O{sub 9}:Ce (LGB:Ce) microcrystals. The plastic scintillator acts to slow impinging neutrons and emits light proportional to the energy lost by the neutrons as they moderate in the detector body. Moderating neutrons that have slowed sufficiently capture in one of the Lithium-6, Boron-10, or Gadolinium-157 atoms in the LGB:Ce scintillator, which then releases the capture energy in a characteristic cerium emission pulse. The measured captured pulses indicate the presence of neutrons. When a scintillating fluor is present in the plastic, the light pulse resulting from the neutron moderating in the plastic is paired with the LGB:Ce capture pulse to identify the energy of the neutron. About 2% of the impinging neutrons lose all of their energy in a single collision with the detector. There is a linear relationship between the pulse areas of this group of neutrons and energy. The other 98% of neutrons have a wide range of collision histories within the detector body. When these neutrons are 'binned' into energy groups, each group contains a distribution of pulse areas. This data was used to assist in the unfolding of the neutron spectra. The unfolded spectra were then validated with known spectra, at both neutron emitting isotopes and fission/accelerator facilities. Having validated spectra, the dose equivalent and dose rate are determined by applying standard, regulatory damage coefficients to the measured neutron counts for each energy bin of the spectra. Testing

  4. Scintillation detectors in computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gilar, O.; Pavlicek, Z.; Jursova, L. (Tesla, Premysleni (Czechoslovakia). Vyzkumny Ustav Pristroju Jaderne Techniky)

    1984-07-01

    A new scintillator, Bi/sub 4/Ge/sub 3/O/sub 12/ (BGO), was tested for use in the detection part of computerized tomographs. In comparison with the NaI(Tl) scintillator it has a three-fold mass stopping power and allows the detection of medium and high energy gamma radiation with a higher detection efficiency, i.e., for the same detection efficiency its size is much smaller. Some other mechanical, physical and optical parameters of the BGO scintillator are given. BGO is prospective for use in high energy spectrometry and may replace NaI(Tl) wherever the following parameters are significant: crystal size, detection efficiency for gamma radiation, and good spatial resolution.

  5. Scintillation-Hardened GPS Receiver

    Science.gov (United States)

    Stephens, Donald R.

    2015-01-01

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

  6. Characterization of liquid scintillation detectors

    CERN Document Server

    Schmidt, D; Böttger, R; Klein, H; Lebreton, L; Neumann, S; Nolte, R; Pichenot, G

    2002-01-01

    Five scintillation detectors of different scintillator size and type were characterized. The pulse height scale was calibrated in terms of electron light output units using photon sources. The response functions for time-of-flight (TOF)-selected monoenergetic neutrons were experimentally determined and also simulated with the NRESP code over a wide energy range. A comparison of the measured and calculated response functions allows individual characteristics of the detectors to be determined and the response matrix to be reliably derived. Various applications are discussed.

  7. Composite scintillators for detection of ionizing radiation

    Science.gov (United States)

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

    2010-12-28

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

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

    CERN Document Server

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

    2014-01-01

    The Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) experiment at the Antiproton Decelerator (AD) facility of CERN constructed segmented scintillators to detect and track the charged pions which emerge from antiproton annihilations in a future superconducting radiofrequency Paul trap for antiprotons. A system of 541 cast and extruded scintillator bars were arranged in 11 detector modules which provided a spatial resolution of 17 mm. Green wavelength-shifting fibers were embedded in the scintillators, and read out by silicon photomultipliers which had a sensitive area of 1 x 1 mm^2. The photoelectron yields of various scintillator configurations were measured using a negative pion beam of momentum p ~ 1 GeV/c. Various fibers and silicon photomultipliers, fiber end terminations, and couplings between the fibers and scintillators were compared. The detectors were also tested using the antiproton beam of the AD. Nonlinear effects due to the saturation of the silicon photomultiplier were seen a...

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

    Science.gov (United States)

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

    2016-01-01

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

  10. Investigation of linear accelerator pulse delivery using fast organic scintillator measurements

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Andersen, Claus Erik; Lindvold, Lars René;

    2010-01-01

    Fiber-coupled organic plastic scintillators present an attractive method for time-resolved dose measurements during radiotherapy. Most organic scintillators exhibit a fast response, making it possible to use them to measure individual high-energy X-ray pulses from a medical linear accelerator. Th...... performed on Varian medical linear accelerators, delivering 6 MV X-ray beams. The dose delivery per radiation pulse was found to agree with expectations within roughly 1%, although minor discrepancies and transients were evident in the measurements....

  11. Reper Radioactive Sources for Time and Energy Calibration of Single Crystal Scintillation Time Spectrometers

    CERN Document Server

    Lebedev, N A; Morozova, N V; Novgorodov, A F; Filossofov, D V

    2000-01-01

    There was made a set of reper radioactive sources for time and energy calibration of the single crystal scintillation time spectrometer. The set consists of ^{73}As, ^{153}Gd, ^{169}Yb, ^{241}Am sources and sources of ^{225}Ac and ^{232}Th including the products of their decay. This set of radioactive sources covers the time interval from 4 ns to 4 mus and energy interval starting from 10 keV. Some of these sources were included in the small size plastic scintillators providing the 4 pi geometry for radiation measurements.

  12. X-ray Scintillation in Lead Halide Perovskite Crystals

    Science.gov (United States)

    Birowosuto, M. D.; Cortecchia, D.; Drozdowski, W.; Brylew, K.; Lachmanski, W.; Bruno, A.; Soci, C.

    2016-11-01

    Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to the presence of heavy atoms, solution-grown hybrid lead halide perovskite single crystals exhibit short X-ray absorption length and excellent detection efficiency. Here we compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional (2D) (EDBE)PbCl4 hybrid perovskite crystals. X-ray excited thermoluminescence measurements indicate the absence of deep traps and a very small density of shallow trap states, which lessens after-glow effects. All perovskite single crystals exhibit high X-ray excited luminescence yields of >120,000 photons/MeV at low temperature. Although thermal quenching is significant at room temperature, the large exciton binding energy of 2D (EDBE)PbCl4 significantly reduces thermal effects compared to 3D perovskites, and moderate light yield of 9,000 photons/MeV can be achieved even at room temperature. This highlights the potential of 2D metal halide perovskites for large-area and low-cost scintillator devices for medical, security and scientific applications.

  13. Effects of hadron irradiation on scintillating fibers

    Energy Technology Data Exchange (ETDEWEB)

    Atac, M. (Univ. of California, Los Angeles, CA (United States) Fermi National Accelerator Lab., Batavia, IL (United States)); Buchanan, C.; Chrisman, D.; Cline, D.; Kolonko, J.; Kubic, J.; Park, J. (Univ. of California, Los Angeles, CA (United States)); Baumbaugh, A.; Binkley, M.; Bross, A.D.; Finley, D.; Elias, J.; Foster, G.W.; Kephart, R.; Kephart, R.; Kim, C.; Park, H.; Pla-Dalmau, A.; Rivetta, C.; Tkaczyk, S.; Wagner, R. (Fermi National Accelerator Lab., Batavia, IL (United States)); Chung, M.; Goldberg, H.; Jeskik, R.; Margulies, S.; Mendez, H.; Solomon, J.; Vaca, F. (Univ. of Illinois, Chicago, IL (United States)); Kelley, C. (Massachusetts College of Pharmacy and Allied Health Sciences, Boston, MA (United States)); Baumbaugh, B.; Bishop, J.; Biswas, N.; Cason, N.; Jacques, J.; Kehoe, R.; Kelly, M.; Kenney, V.; LoSecco, J.; Ruchti, R.; Shephard, W.; Warchol, J.; Wayne, M.; Marchant, J.; Mountain, R.J. (Univ. of Notre Dame, IN (United States)); Davis, D.; Vandergriff, D. (O

    1993-08-01

    Trackers based on scintillating-fiber technology are being considered by the Solenoidal Detector Collaboration at SSC and the D[phi] collaboration at Fermilab. An important issue is the effect of the radiation existing in the detector cores on fiber properties. Most studies of radiation damage in scintillators have irradiated small bulk samples rather than fibers, and have used X-rays, [sup 60]Co gammas, or electron beams, often at accelerated rates. The authors have irradiated some 600 fibers in the Fermilab Tevatron C[phi] area, thereby obtaining a hadronic irradiation at realistic rates. Four-meter-long samples of ten Bicron polystyrene-based fiber types, maintained in air, dry nitrogen, argon, and vacuum atmospheres within stainless-steel tubes, were irradiated for seven weeks at various distances from the accelerator beam pipes. Maximum doses, measured by thermoluminescence detectors, were about 80 Krad. Fiber properties, particularly light yield and attenuation length, have been measured over a one-year period. A description of the work together with the results is presented. At the doses achieved, corresponding to a few years of actual fiber-tracking detector operation, little degradation is observed. In addition, recovery after several days' exposure to air has been noted. Properties of unirradiated samples kept in darkness show no changes after one year.

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

    Science.gov (United States)

    Oliferuk, W.; Maj, M.

    2015-08-01

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

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

    Science.gov (United States)

    Canning, Andrew

    2013-03-01

    Inorganic scintillation phosphors (scintillators) are extensively employed as radiation detector materials in many fields of applied and fundamental research such as medical imaging, high energy physics, astrophysics, oil exploration and nuclear materials detection for homeland security and other applications. The ideal scintillator for gamma ray detection must have exceptional performance in terms of stopping power, luminosity, proportionality, speed, and cost. Recently, trivalent lanthanide dopants such as Ce and Eu have received greater attention for fast and bright scintillators as the optical 5d to 4f transition is relatively fast. However, crystal growth and production costs remain challenging for these new materials so there is still a need for new higher performing scintillators that meet the needs of the different application areas. First principles calculations can provide a useful insight into the chemical and electronic properties of such materials and hence can aid in the search for better new scintillators. In the past there has been little first-principles work done on scintillator materials in part because it means modeling f electrons in lanthanides as well as complex excited state and scattering processes. In this talk I will give an overview of the scintillation process and show how first-principles calculations can be applied to such systems to gain a better understanding of the physics involved. I will also present work on a high-throughput first principles approach to select new scintillator materials for fabrication as well as present more detailed calculations to study trapping process etc. that can limit their brightness. This work in collaboration with experimental groups has lead to the discovery of some new bright scintillators. Work supported by the U.S. Department of Homeland Security and carried out under U.S. Department of Energy Contract no. DE-AC02-05CH11231 at Lawrence Berkeley National Laboratory.

  16. Plastic Jellyfish.

    Science.gov (United States)

    Moseley, Christine

    2000-01-01

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

  17. Scintillation Monitoring Using Asymmetry Index

    Science.gov (United States)

    Shaikh, Muhammad Mubasshir; Mahrous, Ayman; Abdallah, Amr; Notarpietro, Riccardo

    Variation in electron density can have significant effect on GNSS signals in terms of propagation delay. Ionospheric scintillation can be caused by rapid change of such delay, specifically, when they last for a longer period of time. Ionospheric irregularities that account for scintillation may vary significantly in spatial range and drift with the background plasma at speeds of 45 to 130 m/sec. These patchy irregularities may occur several times during night, e.g. in equatorial region, with the patches move through the ray paths of the GNSS satellite signals. These irregularities are often characterized as either ‘large scale’ (which can be as large as several hundred km in East-West direction and many times that in the North-South direction) or ‘small scale’ (which can be as small as 1m). These small scale irregularities are regarded as the main cause of scintillation [1,2]. In normal solar activity conditions, the mid-latitude ionosphere is not much disturbed. However, during severe magnetic storms, the aurora oval extends towards the equator and the equator anomaly region may stretched towards poles extending the scintillation phenomena more typically associated with those regions into mid-latitudes. In such stormy conditions, the predicted TEC may deviate largely from the true value of the TEC both at low and mid-latitudes due to which GNSS applications may be strongly degraded. This work is an attempt to analyze ionospheric scintillation (S4 index) using ionospheric asymmetry index [3]. The asymmetry index is based on trans-ionospheric propagation between GPS and LEO satellites in a radio occultation (RO) scenario, using background ionospheric data provided by MIDAS [4]. We attempted to simulate one of the recent geomagnetic storms (NOAA scale G4) occurred over low/mid-latitudes. The storm started on 26 September 2011 at UT 18:00 and lasted until early hours of 27 September 2011. The scintillation data for the storm was taken from an ionospheric

  18. LHCb Upgrade: Scintillating Fibre Tracker

    Science.gov (United States)

    Tobin, Mark

    2016-07-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  19. A helical scintillating fiber hodoscope

    CERN Document Server

    Altmeier, M; Bisplinghoff, J; Bissel, T; Bollmann, R; Busch, M; Büsser, K; Colberg, T; Demiroers, 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; Naehle, 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

    1999-01-01

    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 deg. <= THETA<=72 deg. and 0 deg. <=phi (cursive,open) Greek<=360 deg. 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. (author)

  20. Dual Readout With PWO Crystals and LuAG Crystal Scintillating Fibers

    CERN Document Server

    Auffray, E; Mavromanolakis, G; Abler, D

    2010-01-01

    One of the main challenges for detectors at future high-energy collider experiments is high-precision measurement of hadrons and jet energy and momentum. Such measurement can be provided by the particle flow approach (PFA) that requires a complex highly segmented calorimeter system to identify and to track all particles in a jet. An alternative so-called dual-readout approach consists of simultaneously recording, in an active medium, scintillation light that is proportional to total energy deposit and Cerenkov light that is proportional to the electromagnetic part only, thus allowing extracting the electromagnetic fraction of the total shower energy on an event-by-event basis. The dual-readout method approach can be implemented using several techniques. The first method proposed uses a copper absorber structure containing two types of fibers: quartz fibers that produce Cerenkov light and plastic scintillating fibers that produce scintillation light. A second method proposed is based on the separation of scint...

  1. Scintillation characteristics of phosphich-detector for detection of beta- and gamma-radiations

    CERN Document Server

    Ananenko, A A; Gavrilyuk, V

    2002-01-01

    The results of the study on the influence of individual peculiarities of the compound scintillation detector structure on the value and stability of the light yield by the gamma- and beta-radiation combined registration are presented. The phosphich detector is manufactured from the sodium iodide monocrystal, activated by thallium, and the scintillation plastic on the polystyrol basis. The comparison of the experimental results with the mathematical modeling data revealed certain regularities of the process of forming the phosphich detector light signal. The recommendations are worked out by means whereof the following characteristics of the scintillation unit: the light yield and its stability, amplitude resolution and the peak-to-valley ratio by the gamma- and beta-radiation registration were improved

  2. Plastic, Fantastic? What We Make. Science and Technology Education in Philippine Society.

    Science.gov (United States)

    Philippines Univ., Quezon City. Inst. for Science and Mathematics Education Development.

    This module provides information about plastics, focusing on the uses of plastic bags in particular. Topic areas considered include: (1) making plastic bags; (2) transparency of plastic bags; (3) plastic bags and food odors; (4) food containers (before and since plastics); and (5) disposing of plastic bags and other plastic products. The text is…

  3. Design and test of a scintillation dosimeter for dosimetry measurements of high energy radiotherapy beams; Conception et realisation d'un dosimetre a scintillation adapte a la dosimetrie de faisceaux de rayonnements ionisants en faisceaux de rayonnements ionisants en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Fontbonne, J.M

    2002-12-01

    This work describes the design and evaluation of the performances of a scintillation dosimeter developed for the dosimetry of radiation beams used in radiotherapy. The dosimeter consists in a small plastic scintillator producing light which is guided by means of a plastic optical fiber towards photodetectors. In addition to scintillation, high energy ionizing radiations produce Cerenkov light both in the scintillator and the optical fiber. Based on a wavelength analysis, we have developed a deconvolution technique to measure the scintillation light in the presence of Cerenkov light. We stress the advantages that are anticipated from plastic scintillator, in particular concerning tissue or water equivalence (mass stopping power, mass attenuation or mass energy absorption coefficients). We show that detectors based on this material have better characteristics than conventional dosimeters such as ionisation chambers or silicon detectors. The deconvolution technique is exposed, as well as the calibration procedure using an ionisation chamber. We have studied the uncertainty of our dosimeter. The electronics noise, the fiber transmission, the deconvolution technique and the calibration errors give an overall combined experimental uncertainty of about 0,5%. The absolute response of the dosimeter is studied by means of depth dose measurements. We show that absolute uncertainty with photons or electrons beams with energies ranging from 4 MeV to 25 MeV is less than {+-} 1 %. Last, at variance with other devices, our scintillation dosimeter does not need dose correction with depth. (author)

  4. Scintillation in the Circinus Galaxy water megamasers

    CERN Document Server

    McCallum, J N

    2004-01-01

    We present observations of the 22 GHz water vapor megamasers in the Circinus galaxy made with the Tidbinbilla 70m telescope. These observations confirm the rapid variability seen earlier by Greenhill et al (1997). We show that this rapid variability can be explained by interstellar scintillation, based on what is now known of the interstellar scintillation seen in a significant number of flat spectrum AGN. The observed variability cannot be fully described by a simple model of either weak or diffractive scintillation.

  5. New scintillation materials and scintiblocs for neutron and γ-rays registration

    Science.gov (United States)

    Koroleva, T. S.; Shulgin, B. V.; Pedrini, Ch.; Ivanov, V. Yu.; Raikov, D. V.; Tcherepanov, A. N.

    2005-01-01

    This paper is a short review of some new scintillation materials, scintillation detectors and scintillation systems for registration of gamma-rays, X-rays, neutrons and neutrinos, which have been developed on the level of inventions and a new fundamental level in the Ural State Technical University-UPI (Ekaterinburg, Russia) and Laboratoire de Physico-Chimie des Matériaux Luminescents (Université Lyon 1, France). The part of Russian patents for this area are presented: some most important new scintillation materials (on the base of lithium hydride, silicate compounds, compounds on the base of aluminates, compounds on the base of fluorides and oxyfluorides, compounds on the base of oxides and oxides crystals, glasses and transparent ceramics) and new scintillation devices (on the base of HgI2, on the base of LiKSO4, sandwich-detectors (organic-inorganic-glass-fiber materials), combine detectors, detectors with photodiodes registration and spectrum shifter, surface scintillation structures and screens, and fiber scintillation devices).

  6. Designing an optimally proportional inorganic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Jai, E-mail: jai.singh@cdu.edu.au [School of Engineering and IT, B-Purple-12, Faculty of EHSE, Charles Darwin University, NT 0909 (Australia); Koblov, Alexander [School of Engineering and IT, B-Purple-12, Faculty of EHSE, Charles Darwin University, NT 0909 (Australia)

    2012-09-01

    The nonproportionality observed in the light yield of inorganic scintillators is studied theoretically as a function of the rates of bimolecular and Auger quenching processes occurring within the electron track initiated by a gamma- or X-ray photon incident on a scintillator. Assuming a cylindrical track, the influence of the track radius and concentration of excitations created within the track on the scintillator light yield is also studied. Analysing the calculated light yield a guideline for inventing an optimally proportional scintillator with optimal energy resolution is presented.

  7. General optical scintillation in turbulent atmosphere

    Institute of Scientific and Technical Information of China (English)

    Ruizhong Rao

    2008-01-01

    A general expression of the scintillation index is proposed for optical wave propagating in turbulent atmosphere under arbitrary fluctuation conditions. The expression depends on extreme behaviors of the scintillation indices under both weak and strong fluctuations. The maximum scintillation index in the onset region and the corresponding Rytov index can be evaluated from the general expression. Plane and spherical waves in the cases of zero and non-zero turbulence inner scale are given as examples for illustration of the general behaviors of scintillation indices.

  8. Plasticity of motor function and surgical outcomes in patients with cerebral arteriovenous malformation involving primary motor area:insight from fMRI and DTI

    Institute of Scientific and Technical Information of China (English)

    Lijun Wang; Fuxin Lin; Jun Wu; Yuming Jiao; Yong Cao; Yuanli Zhao; Shuo Wang

    2016-01-01

    Background:Patients who have a cerebral arteriovenous malformation (cAVMs) in the motor cortex can have displaced function. The finding and its relationship to recovery from surgery is not known. Methods:We present the five cases with cAVMs involving precentral knob and/or paracentral lobule and without preoperative motor deficits. We used motor activation areas derived from Functional functional MRI (fMRI) as a region of interesting (ROI) to launch the plasticity of cerebrospinal tracts (CST). All the results were incorporated into the neuronavigation platform for surgical treatment. Intraoperative electric cortical stimulation (ECS) was used to map motor areas. Modified Rankin Scale (mRS) of hands and feets were performed on postoperative day 2, 7 and at month 3, 6 during follow-up period. All the patients suffered from motor deficits regardless of cortical activation patterns. Results:Three patients showed functionally seeded CST in or around the AVM, and were validated by intraoperative electrical stimulation (ECS). Patient 4 had two aberrant functionally seeded fiber tracts away from the lesion, but were proved to be non-functional by postoperative motor deficits. Patient 3 with motor cortex and fiber tract within a diffuse AVMs nidus, complete paralysis of upper extremity after operation and has a persistent motor deficit during 6-month follow-up period. Conclusions:The plasticity of motor cortex on fMRI doesn’t prevent post-operative motor deficits. Functionally mapped fiber tract within or abutting AVM nidus predicts transient and persistent motor deficit.

  9. Fast Scintillation Probes For Investigation Of Pulsed Neutron Radiation From Small Fusion Devices

    Science.gov (United States)

    Tomaszewski, Krzysztof J.

    2008-04-01

    This paper presents the design as well as laboratory/performance tests results taken by means of the fast scintillation probes. The design of each scintillation probe is based on photomultiplier tube hybrid assembly, which—besides photomultiplier itself—also includes high-voltage divider optimized for recording of fast radiation bursts. Plastic scintillators with short-time response are applied as hard X-ray and neutron radiation detectors. Heavy-duty probe's housing provides efficient shielding against electromagnetic interference and allows carrying out pulsed neutron measurements in a harsh electromagnetic environment. The crucial parameters of scintillation probes have been examined during laboratory tests in which our investigations have been aimed mainly to determine: a time response, an anode radiant sensitivity and an electron transit time dependence on high-voltage supply. During the performance tests, the relative calibration of probes set has been done. It allowed to carry out very accurate measurements of neutron emission anisotropy and investigations of neutron radiation scattering by different materials. The usefulness of presented scintillation probes—embedded in the neutron time-of-flight diagnostic system was proven during experimental campaigns conducted on the plasma-focus PF1000 device.

  10. Optical intensity scintillation in the simulated atmospherical environment

    Science.gov (United States)

    Hajek, Lukas; Latal, Jan; Vanderka, Ales; Vitasek, Jan; Bojko, Marian; Bednarek, Lukas; Vasinek, Vladimir

    2016-09-01

    There are several parameters of the atmospheric environment which have an effect on the optical wireless connection. Effects like fog, snow or rain are ones of the effects which appears tendentiously and which are bound by season, geographic location, etc. One of the effects that appear with various intensity for the whole time is airflow. The airflow changes the local refractive index of the air and areas with lower or higher refractive index form. The light going through these areas refracts and due to the optical intensity scintillates on the detector of the receiver. The airflow forms on the basis of two effects in the atmosphere. The first is wind cut and flowing over barriers. The other is thermal flow when warm air rises to the higher layers of the atmosphere. The heart of this article is creation such an environment that will form airflow and the refractive index will scintillate. For the experiment, we used special laboratory box with high-speed ventilators and heating units to simulate atmospheric turbulence. We monitor the impact of ventilator arrangement and air temperature on the scintillation of the gas laser with wavelength 633 nm/15 mW. In the experiment, there is watched the difference in behavior between real measurement and flow simulation with the same peripheral conditions of the airflow in the area of 500 x 500 cm.

  11. Luminescence and scintillation properties of YAG:Ce single crystal and optical ceramics

    CERN Document Server

    Mihóková, E; Mareš, J A; Beitlerová, A; Vedda, A; Nejezchleb, K; Blažek, K; D’Ambrosio, C

    2007-01-01

    We use various techniques to study optical and scintillation properties of Ce-doped yttrium aluminum garnet, Y3Al5O12 (YAG:Ce), in the form of a high-quality industrial single crystal. This was compared to optical ceramics prepared from YAG:Ce nanopowders. We present experimental data in the areas of optical absorption, radioluminescence, scintillation decay, photoelectron yield, thermally stimulated luminescence and radiation-induced absorption. The results point to an interesting feature—the absence of antisite (YAl, i.e. Y at the Al site) defects in optical ceramics. The scintillation decay of the ceramics is faster than that of the single crystal, but its photoelectron yield (measured with 1 μs integration time) is about 30–40% lower. Apart from the photoelectron yield value the YAG:Ce optical ceramic is fully comparable to a high quality industrial YAG:Ce single crystal and can become a competitive scintillator material.

  12. Mounting LHCb hadron calorimeter scintillating tiles

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    Scintillating tiles are carefully mounted in the hadronic calorimeter for the LHCb detector. These calorimeters measure the energy of particles that interact via the strong force, called hadrons. The detectors are made in a sandwich-like structure where these scintillator tiles are placed between metal sheets.

  13. Performance and characteristics of a new scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Czirr, J.B. [Mission Support Incorporated, Provo, Utah (United States); MacGillivray, G.M. [Nray Services Inc., RP no. 1 Black Bay Road, Petawawa, Ont. K8H2W8 (Canada); MacGillivray, R.R. [Nray Services Inc., RP no. 1 Black Bay Road, Petawawa, Ont. K8H2W8 (Canada); Seddon, P.J. [Nray Services Inc., RP no. 1 Black Bay Road, Petawawa, Ont. K8H2W8 (Canada)

    1999-11-03

    A new class of scintillators for neutron imaging, based upon lithium gadolinium borate, is described. These scintillators offer the ability to tailor their response to the neutron spectrum by varying the relative absorption of neutrons by the key constituents (lithium, gadolinium and boron). The isotopic compositions of each constituent can be varied in order to change the spectral response.

  14. Performance and characteristics of a new scintillator

    CERN Document Server

    Czirr, J B; MacGillivray, R R; Seddon, P J

    1999-01-01

    A new class of scintillators for neutron imaging, based upon lithium gadolinium borate, is described. These scintillators offer the ability to tailor their response to the neutron spectrum by varying the relative absorption of neutrons by the key constituents (lithium, gadolinium and boron). The isotopic compositions of each constituent can be varied in order to change the spectral response.

  15. Development of scintillation materials for PET scanners

    CERN Document Server

    Korzhik, Mikhail; Annenkov, Alexander N; Borissevitch, Andrei; Dossovitski, Alexei; Missevitch, Oleg; Lecoq, Paul

    2007-01-01

    The growing demand on PET methodology for a variety of applications ranging from clinical use to fundamental studies triggers research and development of PET scanners providing better spatial resolution and sensitivity. These efforts are primarily focused on the development of advanced PET detector solutions and on the developments of new scintillation materials as well. However Lu containing scintillation materials introduced in the last century such as LSO, LYSO, LuAP, LuYAP crystals still remain the best PET species in spite of the recent developments of bright, fast but relatively low density lanthanum bromide scintillators. At the same time Lu based materials have several drawbacks which are high temperature of crystallization and relatively high cost compared to alkali-halide scintillation materials. Here we describe recent results in the development of new scintillation materials for PET application.

  16. Inorganic-organic rubbery scintillators

    CERN Document Server

    Gektin, A V; Pogorelova, N; Neicheva, S; Sysoeva, E; Gavrilyuk, V

    2002-01-01

    Spectral-kinetic luminescence properties of films, containing homogeneously dispersed scintillation particles of CsI, CsI:Tl, CsI:Na, and NaI:Tl in optically transparent organosiloxane matrix, are presented. Material is flexible and rubbery and in consequence the detectors of convenient shapes can be produced. It is found that luminescence spectra of the received films are identical whereas decay times are much shorter compared to the same ones of the corresponding single crystals. Layers with pure CsI demonstrate only the fast UV emission (307 nm, 10 ns) without blue microsecond afterglow typical for crystals. The films containing NaI:Tl are non-hygroscopic and preserve scintillation properties for a long time in humid atmosphere unlike single crystals. Organosiloxane layers with CsI:Tl particles provide high light output with good energy resolution for sup 5 sup 5 Fe, sup 1 sup 0 sup 9 Cd, sup 2 sup 4 sup 1 Am sources, and are capable of detecting both X-rays and alpha-, beta-particles.

  17. Development of SiPM-based scintillator tile detectors for a multi-layer fast neutron tracker

    Directory of Open Access Journals (Sweden)

    Jakubek J.

    2012-10-01

    Full Text Available We are developing thin tile scintillator detectors with silicon photomultiplier (SiPM readout for use in a multi-layer fast-neutron tracker. The tracker is based on interleaved Timepix and plastic scintillator layers. The thin 15 × 15 × 2 mm plastic scintillators require suitable optical readout in order to detect and measure the energy lost by energetic protons that have been recoiled by fast neutrons. Our first prototype used dual SiPMs, coupled to opposite edges of the scintillator tile using light-guides. An alternative readout geometry was designed in an effort to increase the fraction of scintillation light detected by the SiPMs. The new prototype uses a larger SiPM array to cover the entire top face of the tile. This paper details the comparative performance of the two prototype designs. A deuterium-tritium (DT fast-neutron source was used to compare the relative light collection efficiency of the two designs. A collimated UV light source was scanned across the detector face to map the uniformity. The new prototype was found to have 9.5 times better light collection efficiency over the original design. Both prototypes exhibit spatial non-uniformity in their response. Methods of correcting this non-uniformity are discussed.

  18. Development of a Hard X-ray focal plane Compton Polarimeter: A compact polarimetric configuration with Scintillators and Si photomultipliers

    CERN Document Server

    Chattopadhyay, T; Goyal, S K; S., Mithun N P; Patel, A R; Shukla, R; Ladiya, T; Shanmugam, M; Patel, V R; Ubale, G P

    2015-01-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm x...

  19. Research activity with different types of scintillation materials

    Science.gov (United States)

    Brinkmann, K.-T.; Borisevich, A.; Diehl, S.; Dormenev, V.; Houzvicka, J.; Korjik, M.; Novotny, R. W.; Zaunick, H.-G.; Zimmermann, S.

    2016-10-01

    Nowadays there is a growing interest and demand in the development of new types of scintillation materials for experimental high energy physics. Future detector developments will focus on cheap, fast, and radiation hard materials, especially for application in collider experiments. The most recent results obtained by the Giessen group in close cooperation with colleagues from different institutes will be presented. The new start of the mass production of high quality lead tungstate crystals (PbWO4, PWO) for electromagnetic calorimetry was started by the company CRYTUR (Turnov, Czech Republic). We will present a detailed progress report on the research program of lead tungstate performed in the last two years. The latest results in the development of LuAG:Ce, YAG:Ce and LYSO:Ce inorganic fibers, grown by the micro pulling down method and cut with the heated wire technique as well as new glass ceramics material BaO*2SiO2 (DSB) doped by Ce and Gd will be presented. In addition, different samples of the organic plastic scintillator EJ-260 produced by the company Eljen Technology (Sweetwater, USA) have been characterized. The study has focused on the change of performance after irradiation with 150 MeV protons up to an integral fluence of 5-1013 protons/cm2 as well as with a strong 60Co gamma-source accumulating an integral dose of 100 Gy.

  20. Preliminary Study of Position-Sensitive Large-Area Radiation Portal Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Chang Hwy; Kim, Hyunok; Moon, Myung Kook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jongyul [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Park, Jong Won; Lim, Yong Kon [Korea Institute of Ocean Science and Technology, Daejeon (Korea, Republic of)

    2013-10-15

    An RPM, which is a passive inspection method, is a system for monitoring the movement of radioactive materials at an airport, seaport, border, etc. To detect a γ-ray, an RPM using the plastic scintillator is generally used. The method of γ-ray detection using an RPM with a plastic scintillator is to measure lights generated by an incident γ-ray in the scintillator. Generally, a large-area RPM uses one or two photomultiplier tubes (PMT) for light collection. However, in this study, we developed a 4-ch RPM that can measure the radiation signal using 4 PMTs. The reason for using 4 PMTs is to calculate the position of the radiation source. In addition, we developed an electric device for acquisition of a 4-ch output signal at the same time. To estimate the performance of the developed RPM, we performed an RPM test using a {sup 60}Co γ-ray check source. In this study, we performed the development of a 4-ch RPM. The major function of the typical RPM is to measure the radiation. However, we developed a position-sensitive 4-ch RPM, which can be used to measure the location of the radiation source, as well as the radiation measurement, at the same time. In the future, we plan to develop an algorithm for a position detection of the radiation. In addition, an algorithm will be applied to an RPM.

  1. Medical imaging scintillators from glass-ceramics using mixed rare-earth halides

    Science.gov (United States)

    Beckert, M. Brooke; Gallego, Sabrina; Ding, Yong; Elder, Eric; Nadler, Jason H.

    2016-10-01

    Recent years have seen greater interest in developing new luminescent materials to replace scintillator panels currently used in medical X-ray imaging systems. The primary areas targeted for improvement are cost and image resolution. Cost reduction is somewhat straightforward in that less expensive raw materials and processing methods will yield a less expensive product. The path to improving image resolution is more complex because it depends on several properties of the scintillator material including density, transparency, and composition, among others. The present study focused on improving image resolution using composite materials, known as glass-ceramics that contain nanoscale scintillating crystallites formed within a transparent host glass matrix. The small size of the particles and in-situ precipitation from the host glass are key to maintaining transparency of the composite scintillator, which ensures that a majority of the light produced from absorbed X-rays can actually be used to create an image of the patient. Because light output is the dominating property that determines the image resolution achievable with a given scintillator, it was used as the primary metric to evaluate performance of the glass-ceramics relative to current scintillators. Several glass compositions were formulated and then heat treated in a step known as "ceramization" to grow the scintillating nanocrystals, whose light output was measured in response to a 65 kV X-ray source. Performance was found to depend heavily on the thermal history of the glass and glass-ceramic, and so additional studies are required to more precisely determine optimal process temperatures. Of the compositions investigated, an alumino-borosilicate host glass containing 56mol% scintillating rare-earth halides (BaF2, GdF3, GdBr3, TbF3) produced the highest recorded light output at nearly 80% of the value recorded using a commercially-available GOS:Tb panel as a reference.

  2. Pulse-shape discrimination scintillators for homeland security applications

    Science.gov (United States)

    Ellis, Mark E.; Duroe, Kirk; Kendall, Paul A.

    2016-09-01

    An extensive programme of research has been conducted for scintillation liquids and plastics capable of neutron-gamma discrimination for deployment in future passive and active Homeland Security systems to provide protection against radiological and nuclear threats. The more established detection materials such as EJ-301 and EJ-309 are compared with novel materials such as EJ-299-33 and p-terphenyl. This research also explores the benefits that can be gained from improvements in the analogue-to-digital sampling rate and sample bit resolution. Results are presented on the Pulse Shape Discrimination performance of various detector and data acquisition combinations and how optimum configurations from these studies have been developed into field-ready detector arrays. Early results from application-specific experimental configurations of multi-element detector arrays are presented.

  3. Control of time stability of scintillation spectrometer of delayed coincidences

    CERN Document Server

    Morozov, V A

    2002-01-01

    Paper describes a system to control time stability of a two-detector plastic scintillation spectrometer of three-dimensional coincides. A two-reference control system incorporates a light guide base delay optical line, two light diodes and a two-channel generator of nanosecond pulses. A distinguishing feature of the design system is application of one delay line to form both advance and delay time signal as to the real coincidences in the studied radioactive source. The designed system of control enables to measure periods of half-decay of nuclei excited states within 40-100 ns range ensuring control of position of coincidence curve gravity centers within 4 ps limits

  4. Measuring the attenuation length in liquid scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Hellgartner, Dominikus; Oberauer, Lothar; Prummer, Sabrina; Sawatzki, Julia; Zimmer, Vincenz [Technische Universitaet Muenchen, Physik Departement E15, James Franck Strasse, 85748 Garching (Germany); Ulrich, Andreas [Technische Universitaet Muenchen, Physik Departement E12, James Franck Strasse, 85748 Garching (Germany)

    2015-07-01

    The next generation of liquid scintillator detectors like the proposed LENA detector or the planned JUNO detector will feature diameters of order 30 m. Due to this vast size, the optical quality of the scintillator is of crucial importance. To determine the attenuation length of liquid scintillators, an experiment with a 5 m long measurement section was set-up in the underground laboratory in Garching. The current set-up of the experiment is presented along with a discussion of the results of the first measurements. Additionally, there is an outlook towards possible upgrades of the experiment in the future.

  5. Scintillation particle detection based on microfluidics

    CERN Document Server

    Mapelli, A; Renaud, P; Gorini, B; Trivino, N Vico; Jiguet, S; Vandelli, W; Haguenauer, M

    2010-01-01

    A novel type of particle detector based on scintillation, with precise spatial resolution and high radiation hardness, is being studied. It consists of a single microfluidic channel filled with a liquid scintillator and is designed to define an array of scintillating waveguides each independently coupled to a photodetector. Prototype detectors built using an SU-8 epoxy resin have been tested with electrons from a radioactive source. The experimental results show a light yield compatible with the theoretical expectations and confirm the validity of the approach. (C) 2010 Elsevier B.V. All rights reserved.

  6. X-ray Scintillation in Lead Halide Perovskite Crystals

    CERN Document Server

    Birowosuto, M D; Drozdowski, W; Brylew, K; Lachmanski, W; Bruno, A; Soci, C

    2016-01-01

    Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to the presence of heavy atoms, solution-grown hybrid lead halide perovskite single crystals exhibit short X-ray absorption length and excellent detection efficiency. Here we compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional (2D) (EDBE)PbCl4 hybrid perovskite crystals. X-ray excited thermoluminescence measurements indicate the absence of deep traps and a very small density of shallow trap states, which lessens after-glow effects. All perovskite single crystals exhibit high X-ray excited luminescence yields of >120,000 photons/MeV at low temperature. Although thermal quenching is significant at room temperature, the large exciton binding energy of 2D (EDBE)PbCl4 significantly reduces thermal effects compared to 3D perovskites, and moderate light yie...

  7. Radon gamma-ray spectrometry with YAP:Ce scintillator

    CERN Document Server

    Plastino, W; De Notaristefani, F

    2002-01-01

    The detection properties of a YAP:Ce scintillator (YAlO sub 3 :Ce crystal) optically coupled to a Hamamatsu H5784 photomultiplier with standard bialkali photocathode have been analyzed. In particular, the application to radon and radon-daughters gamma-ray spectrometry was investigated. The crystal response has been studied under severe extreme conditions to simulate environments of geophysical interest, particularly those found in geothermal and volcanic areas. Tests in water up to a temperature of 100 deg.C and in acids solutions such as HCl (37%), H sub 2 SO sub 4 (48%) and HNO sub 3 (65%) have been performed. The measurements with standard radon sources provided by the National Institute for Metrology of Ionizing Radiations (ENEA) have emphasized the non-hygroscopic properties of the scintillator and a small dependence of the light yield on temperature and HNO sub 3. The data collected in this first step of our research have pointed out that the YAP:Ce scintillator can allow high response stability for rad...

  8. Measurement of Radiation Damage of Water-based Liquid Scintillator and Liquid Scintillator

    CERN Document Server

    Bignell, Lindsey J; Hans, Sunej; Jaffe, David E; Rosero, Richard; Vigdor, Steven; Viren, Brett; Worcester, Elizabeth; Yeh, Minfang; Zhang, Chao

    2015-01-01

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of $5\\%$ scintillating phase) exhibit light yield reductions of $1.74 \\pm 0.55 \\%$ and $1.31 \\pm 0.59 \\%$ after $\\approx$ 800 Gy of proton dose, respectively. Whilst some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical conte...

  9. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  10. Plastic Fishes

    CERN Multimedia

    Trettnak, Wolfgang

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness. The slideshow below gives you a taste of the artworks by Wolfgang Trettnak and Margarita Cimadevila.

  11. Effect Factors of Liquid Scintillation Analysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Over the past decades, the liquid scintillation analysis (LSA) technique remains one of the most popular experimental tools used for the quantitative analysis of radionuclide, especially low-energy β

  12. Pulsar Scintillation and the Local Bubble

    CERN Document Server

    Bhat, N D R; Rao, A P; Gupta, Yashwant

    1998-01-01

    We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 caried out using the Ooty Radio Telescope (ORT) at 327 MHz, to investigate the distribution of ionized material in the local interstellar medium. Observations were made during the period January 1993 to August 1995, in which the dynamic scintillation spectra of these pulsars were regularly monitored over 10 - 90 epochs spanning 100 days. Reliable and accurate estimates of strengths of scattering have been deduced from the scintillation parameters averaged out for their long-term fluctuations arising from refractive scintillation (RISS) effects. Our analysis reveals several anomalies in the scattering strength, which suggest tht the distribution of scattering material in the Solar neighborhood is not uniform. We have modelled these anomalous scattering effects in terms of inhomogeneities in the distribution of electron dnsity fluctuations in the local interstellar medium (LIS...

  13. Testing Gravity with Pulsar Scintillation Measurements

    CERN Document Server

    Yang, Huan; Pen, Ue-Li

    2016-01-01

    We propose to use pulsar scintillation measurements to test predictions of alternative theories of gravity. Comparing to single-path pulsar timing measurements, the scintillation measurements can achieve a factor of 10^5 improvement in timing accuracy, due to the effect of multi-path interference. Previous scintillation measurements of PSR B0834+06 have data acquisition for hours, making this approach sensitive to mHz gravitational waves. Therefore it has unique advantages in measuring gravitational effect or other mechanisms (at mHz and above frequencies) on light propagation. We illustrate its application in constraining scalar gravitational-wave background, in which case the sensitivities can be greatly improved with respect to previous limits. We expect much broader applications in testing gravity with existing and future pulsar scintillation observations.

  14. Development of radiation detection and measurement system - Development of scintillation radiation sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hee Dong; Kim, Wan [Kyungpook National University, Taegu (Korea); Kim, Do Sung [Taegu University, Taegu (Korea)

    2000-03-01

    We have been fabricated CsI(Tl) scintillation crystals and plastic scintillators for radiation-based measuring equipment. CsI (Tl) single crystals doped with thallium as an activator were grown using the Czochralski method. The crystal structure of grown CsI(Tl) was bcc, and it was confirmed that its lattice constant was 4,568 A. The spectral range of luminescence of CsI(Tl) was 350 {approx} 700 nm independent of thallium concentration, and the fast component of the luminescence was decreased with increasing thallium concentration. The energy resolution of CsI(Tl) scintillator doped with 0.1 mole% thallium was about 9% for 137 Cs {gamma}-rays. The relation formula of {gamma}-ray energy versus energy resolution was ln(FWHM%)=-0.705ln({epsilon})+6.75. The radiation damage of CsI(Tl) increased in proportion to thallium concentration and radiation damage of CsI(Tl) increased in proportion to thallium concentration and radiation dosage, and the irradiated crystals were colored reddish. The radiation induced absorption bands appeared around 355, 425, 520 and 555 nm, and their energy level were about 3.50, 2.88, 2.39 and 2.21 eV. Plastic scintillators were fabricated thermal polymerization method. Those were polymerizing at 120 deg. C, during 72 hours, and annealing at 75 deg. C, during 24 hours. When the concentration of 1st solute was 1.5 wt% and concentration of 2nd solute was 0.01 wt%, the characteristics of scintillation were very excellent. Also 3.0 wt% tetraphenyl lead were loaded to improve the detection efficiency of {gamma}-ray. The range of emission spectrum was 400 {approx} 450nm, and the central peak was 415 nm. The radiation damage was not appear under 1*10{sup 3}Gy, but the color of plastic scintillator was changed to brown, over 1*10{sup 4}Gy exposured. 84 refs., 39 figs. (Author)

  15. Scintillator-CCD camera system light output response to dosimetry parameters for proton beam range measurement

    Energy Technology Data Exchange (ETDEWEB)

    Daftari, Inder K., E-mail: idaftari@radonc.ucsf.edu [Department of Radiation Oncology, 1600 Divisadero Street, Suite H1031, University of California-San Francisco, San Francisco, CA 94143 (United States); Castaneda, Carlos M.; Essert, Timothy [Crocker Nuclear Laboratory,1 Shields Avenue, University of California-Davis, Davis, CA 95616 (United States); Phillips, Theodore L.; Mishra, Kavita K. [Department of Radiation Oncology, 1600 Divisadero Street, Suite H1031, University of California-San Francisco, San Francisco, CA 94143 (United States)

    2012-09-11

    The purpose of this study is to investigate the luminescence light output response in a plastic scintillator irradiated by a 67.5 MeV proton beam using various dosimetry parameters. The relationship of the visible scintillator light with the beam current or dose rate, aperture size and the thickness of water in the water-column was studied. The images captured on a CCD camera system were used to determine optimal dosimetry parameters for measuring the range of a clinical proton beam. The method was developed as a simple quality assurance tool to measure the range of the proton beam and compare it to (a) measurements using two segmented ionization chambers and water column between them, and (b) with an ionization chamber (IC-18) measurements in water. We used a block of plastic scintillator that measured 5 Multiplication-Sign 5 Multiplication-Sign 5 cm{sup 3} to record visible light generated by a 67.5 MeV proton beam. A high-definition digital video camera Moticam 2300 connected to a PC via USB 2.0 communication channel was used to record images of scintillation luminescence. The brightness of the visible light was measured while changing beam current and aperture size. The results were analyzed to obtain the range and were compared with the Bragg peak measurements with an ionization chamber. The luminescence light from the scintillator increased linearly with the increase of proton beam current. The light output also increased linearly with aperture size. The relationship between the proton range in the scintillator and the thickness of the water column showed good linearity with a precision of 0.33 mm (SD) in proton range measurement. For the 67.5 MeV proton beam utilized, the optimal parameters for scintillator light output response were found to be 15 nA (16 Gy/min) and an aperture size of 15 mm with image integration time of 100 ms. The Bragg peak depth brightness distribution was compared with the depth dose distribution from ionization chamber measurements

  16. Spectrometric characteristics of polystyrene scintillation films

    CERN Document Server

    Astvatsaturov, A R; Gavalyan, V B; Gavalyan, V G

    1999-01-01

    The spectrometric characteristics of five types of polystyrene scintillation films with thicknesses of 10, 30, 50 and 80 mu m and of analogous 250 mu m thick plates irradiated with sup 2 sup 3 sup 9 Pu, sup 2 sup 3 sup 8 Pu and sup 2 sup 2 sup 6 Ra sources of alpha-particles have been studied. The prospects of utilization of scintillation films as radiators for detection of heavy charged particles and measurement of their energy was experimentally shown.

  17. Multi-GNSS for Ionospheric Scintillation Studies

    Science.gov (United States)

    Morton, Y.

    2015-12-01

    GNSS have been widely used for ionospheric monitoring. We anticipate over 160 GNSS satellites broadcasting 400 signals by 2023, nearly double the number today. With their well-defined signal structures, high spatial density and spectral diversity, GNSS offers low cost and distributed passive sensing of ionosphere effects. There are, however, many challenges to utilize GNSS resources to characterize and forecast ionospheric scintillation. Originally intended for navigation purposes, GNSS receivers are designed to filter out nuisance effects due to ionosphere effects. GNSS measurements are plagued with errors from multipath, oscillator jitters, processing artifacts, and neutral atmosphere effects. Strong scintillation events are often characterized by turbulent structures in ionosphere, causing simultaneous deep amplitude fading and abrupt carrier phase changes. The combined weak signal and high carrier dynamics imposes conflicting requirements for GNSS receiver design. Therefore, GNSS receivers often experience cycle slips and loss of lock of signals during strong scintillation events. High quality, raw GNSS signals bearing space weather signatures and robust receiver algorithms designed to capture these signatures are needed in order for GNSS to be a reliable and useful agent for scintillation monitoring and forecasting. Our event-driven, reconfigurable data collection system is designed to achieve this purpose. To date, our global network has collected ~150TB of raw GNSS data during space weather events. A suite of novel receiver processing algorithms has been developed by exploitating GNSS spatial, frequency, temporal, and constellation diversity to process signals experiencing challenging scintillation impact. The algorithms and data have advanced our understanding of scintillation impact on GNSS, lead to more robust receiver technologies, and enabled high spatial and temporal resolution depiction of ionosphere responses to solar and geomagnetic conditions. This

  18. Single and multichannel scintillating fiber dosimeter for radiotherapic beams with SiPM readout

    Science.gov (United States)

    Berra, A.; Ferri, A.; Novati, C.; Ostinelli, A.; Paternoster, G.; Piemonte, C.; Prest, M.; Vallazza, E.

    2016-12-01

    The treatment of many neoplastic diseases requires the use of radiotherapy, which consists in the irradiation of the tumor, identified as the target volume, with ionizing radiations generated both by administered radiopharmaceuticals or by linear particle accelerators (LINACs). The radiotherapy beam delivered to the patient must be regularly checked to assure the best tumor control probability: this task is performed with dosimeters, i.e. devices able to provide a measurement of the dose deposited in their sensitive volume. This paper describes the development of two scintillator dosimeter prototypes for radiotherapic applications based on plastic scintillating fibers read out by high dynamic range Silicon PhotoMultipliers. The first dosimeter, consisting of a single-channel prototype with a pair of optical fibers, a scintillating and a white one, read out by two SiPMs, has been fully characterized and led to the development of a second multi-channel dosimeter based on an array of scintillating fibers: this device represents the first step towards the assembly of a "one-shot" device, capable to perform some of the daily quality controls in a few seconds. The dosimeters characterization was performed with a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT).

  19. Response of cooled PWO scintillators readout with avalanche photodiodes to low-energy gamma-rays

    Science.gov (United States)

    Melnychuk, D.; Czarnacki, W.; Kalicy, G.; Keşik, G.; Korman, A.; Kozlowski, T.; Mykulyak, A.; Novotny, R. W.; Wojtkowska, J.; Zwieglinski, B.

    2009-08-01

    Identification of π0 and η mesons by detecting both γ-rays from their decay is a prerequisite for suppressing undesired background in studies of photon transitions between the states of charmonium in the physics program of PANDA. To achieve this goal the detection threshold of the PANDA electromagnetic calorimeter (EMC) should be as low as possible. An experimental setup intended for measurements of the response of cooled PWO scintillators in the energy range 4.4-20 MeV has been designed and constructed. The setup uses γ-rays emitted in reactions induced by protons with light nuclei. Events with full-energy expended in PWO are selected by enclosing the studied 20×20×200 mm PWO-II scintillator in a cylinder of EJ-200 plastic scintillator, whose two halves are read out independently. A comparison of the relative Gaussian dispersions, σ/E, obtained by us for the three energies in the above energy range, indicates that a smooth dependence established at MAMI, for a matrix of 3×3 PWO-II scintillators between 40.9 and 674.5 MeV, also gives a valid extrapolation into the range of these very low energies.

  20. Response of a lithium gadolinium borate scintillator in monoenergetic neutron fields.

    Science.gov (United States)

    Williams, A M; Beeley, P A; Spyrou, N M

    2004-01-01

    Accurate estimation of neutron dose requires knowledge of the neutron energy distribution in the working environment. Existing neutron spectrometry systems, Bonner spheres for example, are large and bulky, and require long data acquisition times. A portable system that could indicate the approximate neutron energy spectrum in a short time would be extremely useful in radiation protection. A composite scintillator, consisting of lithium gadolinium borate crystals in a plastic scintillator matrix, produced by Photogenics is being tested for this purpose. A prototype device based on this scintillator and digital pulse processing electronics has been calibrated using quasi-monoenergetic neutron fields at the low-scatter facility of the UK National Physical Laboratory (NPL). Energies selected were 144, 250, 565, 1400, 2500 and 5000 keV, with correction for scattered neutrons being made using the shadow cone technique. Measurements were also made in the NPL thermal neutron field. Pulse distributions collected with the digitiser in capture-gated mode are presented, and detection efficiency and energy resolution derived. For comparison, neutron spectra were also collected using the commercially available Microspec N-Probe from Bubble Technology Industries, which consists of an NE213 scintillator and a 3He proportional counter.

  1. GREEN PLASTIC: A NEW PLASTIC FOR PACKAGING

    OpenAIRE

    Mr. Pankaj Kumar*, Sonia

    2016-01-01

    This paper gives a brief idea about a new type of plastic called as bio-plastic or green plastic. Plastic is used as a packaging material for various products, but this plastic is made up of non renewable raw materials. There are various disadvantages of using conventional plastic like littering, CO2 production, non-degradable in nature etc. To overcome these problems a new type of plastic is discovered called bio-plastic or green plastic. Bio-plastic is made from renewable resources and also...

  2. Ionospheric scintillation effects on single frequency GPS

    Science.gov (United States)

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

    2008-04-01

    Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active within, although not limited to, a belt encircling the Earth within 20 degrees of the geomagnetic equator. As GPS applications and users increase, so does the potential for degraded precision and availability from scintillation. We examined amplitude scintillation data spanning 7 years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/American longitudinal sector as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K. in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at 1 min resolution. We examine diurnal, seasonal, and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

  3. Scintillation light, ionization yield and scintillation decay times in high pressure xenon and xenon methane

    NARCIS (Netherlands)

    Pushkin, K. N.; Akimov, D. Y.; Burenkov, A. A.; Dmitrenko, V. V.; Kovalenko, A. G.; Lebedenko, V. N.; Kuznetsov, I. S.; Stekhanov, V. N.; Tezuka, C.; Ulin, S. E.; Uteshev, Z. M.; Vlasik, K. F.

    2007-01-01

    Scintillation light, ionization yield and scintillation decay times have been measured in xenon and in its mixture with a 0.05% concentration of methane as a function of the reduced electric field (E/N)-the ratio of the electric field strength to the number density of gas-at a pressure of 21 atm. Th

  4. Plastic condoms.

    Science.gov (United States)

    1968-01-01

    Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly

  5. Role of hot electron transport in scintillators: A theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Huihui [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Key Lab. of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen Univ. (China); Li, Qi [Physical Sciences Division, IBM TJ Watson Research Center, Yorktown Heights, NY (United States); Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL (United States); Lu, Xinfu; Williams, R.T. [Department of Physics, Wake Forest University, Winston Salem, NC (United States); Qian, Yiyang [College of Engineering and Applied Science, Nanjing University (China); Wu, Yuntao [Scintillation Materials Research Center, University of Tennessee, Knoxville, TN (United States)

    2016-10-15

    Despite recent intensive study on scintillators, several fundamental questions on scintillator properties are still unknown. In this work, we use ab-initio calculations to determine the energy dependent group velocity of the hot electrons from the electronic structures of several typical scintillators. Based on the calculated group velocities and optical phonon frequencies, a Monte-Carlo simulation of hot electron transport in scintillators is carried out to calculate the thermalization time and diffusion range in selected scintillators. Our simulations provide physical insights on a recent trend of improved proportionality and light yield from mixed halide scintillators. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Plastic Bronchitis.

    Science.gov (United States)

    Rubin, Bruce K

    2016-09-01

    Plastic bronchitis is an uncommon and probably underrecognized disorder, diagnosed by the expectoration or bronchoscopic removal of firm, cohesive, branching casts. It should not be confused with purulent mucous plugging of the airway as seen in patients with cystic fibrosis or bronchiectasis. Few medications have been shown to be effective and some are now recognized as potentially harmful. Current research directions in plastic bronchitis research include understanding the genetics of lymphatic development and maldevelopment, determining how abnormal lymphatic malformations contribute to cast formation, and developing new treatments.

  7. Luminosity measurement at ATLAS-Development, construction and test of scintillating fibre prototype detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ask, S. [CERN, PH Department, Geneva (Switzerland); Barrillon, P. [Laboratoire d' Accelerateur Lineaire, Orsay (France); Braem, A. [CERN, PH Department, Geneva (Switzerland); Cheiklali, C. [Laboratoire d' Accelerateur Lineaire, Orsay (France); Efthymiopoulos, I. [CERN, PH Department, Geneva (Switzerland); Fournier, D. [Laboratoire d' Accelerateur Lineaire, Orsay (France); Taille, C. de la [Laboratoire d' Accelerateur Lineaire, Orsay (France); Di Girolamo, B. [CERN, PH Department, Geneva (Switzerland); Grafstrom, P. [CERN, PH Department, Geneva (Switzerland); Joram, C. [CERN, PH Department, Geneva (Switzerland)]. E-mail: christian.joram@cern.ch; Haguenauer, M. [Ecole Polytechnique, Palaiseau (France); Hedberg, V. [University of Lund (Sweden); Lavigne, B. [Laboratoire d' Accelerateur Lineaire, Orsay (France); Maio, A. [LIP - Laboratorio de Instrumentacao e Fisica Experimental de Particulas and CFNUL - Centro de Fisica Nuclear da Universidade de Lisboa, Lisbon (Portugal); Mapelli, A. [CERN, PH Department, Geneva (Switzerland); Mjoernmark, U. [University of Lund (Sweden); Puzo, P. [Laboratoire d' Accelerateur Lineaire, Orsay (France); Rijssenbeek, M. [Stony Brook University, New York (United States); Santos, J. [LIP - Laboratorio de Instrumentacao e Fisica Experimental de Particulas and CFNUL - Centro de Fisica Nuclear da Universidade de Lisboa, Lisbon (Portugal); Saraiva, J.G. [LIP - Laboratorio de Instrumentacao e Fisica Experimental de Particulas and CFNUL - Centro de Fisica Nuclear da Universidade de Lisboa, Lisbon (Portugal); Stenzel, H. [II. Physikalisches Institut, Justus-Liebig-Universitaet, Giessen (Germany); Thioye, M. [Stony Brook University, New York (United States); Valladolid, E. [CERN, PH Department, Geneva (Switzerland); Vorobel, V. [Faculty of Mathematics and Physics, Charles University in Prague (Czech Republic)

    2006-12-01

    We are reporting about a scintillating fibre tracking detector which is proposed for the precise determination of the absolute luminosity of the CERN LHC at interaction point 1 where the ATLAS experiment is located. The detector needs to track protons elastically scattered under {mu}rad angles in direct vicinity to the LHC beam. It is based on square shaped scintillating plastic fibres read out by multi-anode photomultiplier tubes and is housed in Roman Pots. We describe the design and construction of prototype detectors and the results of a beam test experiment at DESY. The excellent detector performance established in this test validates the detector design and supports the feasibility of the proposed challenging method of luminosity measurement.

  8. Luminosity Measurement at ATLAS Development, Construction and Test of Scintillating Fibre Prototype Detectors

    CERN Document Server

    Ask, S; Braem, André; Cheiklali, C; Efthymiopoulos, I; Fournier, D; de La Taille, C; Di Girolamo, B; Grafström, P; Joram, C; Haguenauer, Maurice; Hedberg, V; Lavigne, B; Maio, A; Mapelli, A; Mjörnmark, U; Puzo, P; Rijssenbeek, M; Santos, J; Saraiva, J G; Stenzel, H; Thioye, M; Valladolid, E; Vorobel, V

    2006-01-01

    We are reporting about a scintillating fibre tracking detector which is proposed for the precise determination of the absolute luminosity of the CERN LHC at interaction point 1 where the ATLAS experiment is located. The detector needs to track protons elastically scattered under $\\mu$rad angles in direct vicinity to the LHC beam. It is based on square shaped scintillating plastic fibres read out by multi-anode photomultiplier tubes and is housed in Roman Pots. We describe the design and construction of prototype detectors and the results of a beam test experiment at DESY. The excellent detector performance established in this test validates the detector design and supports the feasibility of the proposed challenging method of luminosity measurement.

  9. Novel Scintillating Materials Based on Phenyl-Polysiloxane for Neutron Detection and Monitoring

    CERN Document Server

    Degerlier, M; Gramegna, F; Marchi, T; Palma, M Dalla; Cinausero, M; Maggioni, G; Quaranta, A; Collazuol, G; Bermudez, J

    2013-01-01

    Neutron detectors are extensively used at many nuclear research facilities across Europe. Their application range covers many topics in basic and applied nuclear research: in nuclear structure and reaction dynamics (reaction reconstruction and decay studies); in nuclear astrophysics (neutron emission probabilities); in nuclear technology (nuclear data measurements and in-core/off-core monitors); in nuclear medicine (radiation monitors, dosimeters); in materials science (neutron imaging techniques); in homeland security applications (fissile materials investigation and cargo inspection). Liquid scintillators, widely used at present, have however some drawbacks given by toxicity, flammability, volatility and sensitivity to oxygen that limit their duration and quality. Even plastic scintillators are not satisfactory because they have low radiation hardness and low thermal stability. Moreover organic solvents may affect their optical properties due to crazing. In order to overcome these problems, phenyl-polysilox...

  10. A 1 mm Scintillating Fibre Tracker Readout by a Multi-anode Photomultiplier

    CERN Document Server

    Leverington, B D; Campana, P; Rosellini, R

    2011-01-01

    This note describes a prototype particle tracking detector constructed with 1 mm plastic scintillating fibres with a 64 channel Hamamatsu H8500 flat-panel multi-anode photomultiplier readout. Cosmic ray tracks from an array of 11 gas-filled drift tubes were matched to signals in the scintillating fibres in order to measure the resolution and efficiency of tracks reconstructed in the fibre-based tracker. A GEANT4 detector simulation was also developed to compare cosmic ray data with MC results and is discussed in the note. Using the parameters measured in this experimental setup, modified fibre tracker designs are suggested to improve resolution and efficiency in future prototypes to meet modern detector specifications.

  11. The design and construction of the beam scintillation counter for CMS

    CERN Document Server

    Bell, Alan James

    2008-01-01

    This thesis presents the design qualification and construction of the Beam Scintillator Counter (BSC) for the CMS Collaboration at CERN in 2007 - 2008. The BSC detector is designed to aid in the commissioning of the Compact Muon Solenoid (CMS) during the first 2 years of operation and provide technical triggering for beam halo and minimum-bias events. Using plastic scintillator tiles mounted at both ends of CMS, it will detect minimum ionizing particles through the low-to-mid luminosity phases of the Large Hadron Collider (LHC) commissioning. During these early phases, the BSC will provide probably the most interesting and widely used data of any of the CMS sub-detectors and will be employed in the track based alignment procedure of the central tracker and commissioning of the Forward Hadron Calorimeter.

  12. Differentiation method for localization of Compton edge in organic scintillation detectors

    CERN Document Server

    Safari, M J; Afarideh, H

    2016-01-01

    This paper, presents a simple method for accurate calibration of organic scintillation detectors. The method is based on the fact that differentiating the response function leads to accurate estimation of the Compton edge. The differentiation method in addition to the location of the Compton edge, gives insights into the parameters of the folded Gaussian function which is useful for determination of the energy resolution. Moreover, it is observed that the uncorrelated noise in the measurement of the response function does not impose significant uncertainties in the evaluations. By simulation of the bounded electrons and considering the Doppler effects, we are able to calculate a first estimation for the intrinsic Doppler resolution of a plastic scintillator, benefiting from the capability of the differentiation method.

  13. Development of a Real-Time Ion Spectrometer with a Scintillator for Laser-Driven Ion Acceleration Experiments

    Institute of Scientific and Technical Information of China (English)

    XU Miao-Hua; David Neely; Paul McKenna; WANG Zhao-Hua; WEI Zhi-Yi; YAN Xue-Qing; LI Yu-Tong; LI Ying-Jun; ZHANG Jie; LI Hong-Wei; LIU Bi-Cheng; LIU Feng; SU Lu-Ning; DU Fei; ZHANG Lu; ZHENG Yi; MA Jing-Long

    2011-01-01

    A real-time ion spectrometer mainly based on a high-resolution Thomson parabola and a plastic scintillator is designed and developed. The spectrometer is calibrated by protons from an electrostatic accelerator. The feasibility and reliability of the diagnostics ore demonstrated in laser-driven ion acceleration experiments performed on the XL-H laser facility. The proton spectrum extrapolated from the scintillator data is in excellent agreement with the CR39 spectrum in terms of beam temperature and the cutoff energy. This real-time spectrometer allows an online measurement of the ion spectra in single shot, which enables efficient and statistical studies and applications in high-repetition-rate laser acceleration experiments.%@@ A real-time ion spectrometer mainly based on a high-resolution Thomson parabola and a plastic scintillator is designed and developed.The spectrometer is calibrated by protons from an electrostatic accelerator.The feasi-bility and reliability of the diagnostics are demonstrated in laser-driven ion acceleration experiments performed on the XL-Ⅱ laser facility.The proton spectrum extrapolated from the scintillator data is in excellent agreement with the CR39 spectrum in terms of beam temperature and the cutoff energy.This real-time spectrometer allows an online measurement of the ion spectra in single shot,which enables efficient and statistical studies and applications in high-repetition-rate laser acceleration experiments.

  14. Mixed plastics recycling technology

    CERN Document Server

    Hegberg, Bruce

    1995-01-01

    Presents an overview of mixed plastics recycling technology. In addition, it characterizes mixed plastics wastes and describes collection methods, costs, and markets for reprocessed plastics products.

  15. Plastic fish

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness.   Artwork by Wolfgang Trettnak. Packaging materials, consumer goods (shoes, kids’ toys, etc.), leftovers from fishing and aquaculture activities… our oceans and beaches are full of plastic litter. Most of the debris from beaches is plastic bottles. “PET bottles have high durability and stability,” explains Wolfgang Trettnak, a chemist by education and artist from Austria, who gave a lecture on this topic organised by the Staff Association at CERN on 26 May. “PET degrades very slowly and the estimated lifetime of a bottle is 450 years.” In addition to the beach litter accumulated from human use, rivers bring several ki...

  16. Scintillation Detectors for Charged Particles and Photons

    CERN Document Server

    Lecoq, P

    2011-01-01

    Scintillation Detectors for Charged Particles and Photons in 'Charged Particle Detectors - Particle Detectors and Detector Systems', part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B1: Detectors for Particles and Radiation. Part 1: Principles and Methods'. This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Subsection '3.1.1 Scintillation Detectors for Charged Particles and Photons' of Section '3.1 Charged Particle Detectors' of Chapter '3 Particle Detectors and Detector Systems' with the content: 3.1.1 Scintillation Detectors for Charged Particles and Photons 3.1.1.1 Basic detector principles and scintillator requirements 3.1.1.1.1 Interaction of ionizing radiation with scintillator material 3.1.1.1.2 Important scint...

  17. X-ray imaging with scintillator-sensitized hybrid organic photodetectors

    Science.gov (United States)

    Büchele, Patric; Richter, Moses; Tedde, Sandro F.; Matt, Gebhard J.; Ankah, Genesis N.; Fischer, Rene; Biele, Markus; Metzger, Wilhelm; Lilliu, Samuele; Bikondoa, Oier; MacDonald, J. Emyr; Brabec, Christoph J.; Kraus, Tobias; Lemmer, Uli; Schmidt, Oliver

    2015-12-01

    Medical X-ray imaging requires cost-effective and high-resolution flat-panel detectors for the energy range between 20 and 120 keV. Solution-processed photodetectors provide the opportunity to fabricate detectors with a large active area at low cost. Here, we present a disruptive approach that improves the resolution of such detectors by incorporating terbium-doped gadolinium oxysulfide scintillator particles into an organic photodetector matrix. The X-ray induced light emission from the scintillators is absorbed within hundreds of nanometres, which is negligible compared with the pixel size. Hence, optical crosstalk, a limiting factor in the resolution of scintillator-based X-ray detectors, is minimized. The concept is validated with a 256 × 256 pixel detector with a resolution of 4.75 lp mm-1 at a MTF = 0.2, significantly better than previous stacked scintillator-based flat-panel detectors. We achieved a resolution that proves the feasibility of solution-based detectors in medical applications. Time-resolved electrical characterization showed enhanced charge carrier mobility with increased scintillator filling, which is explained by morphological changes.

  18. The feasibility of using boron-loaded plastic fibers for neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Grazioso, R.F.; Heger, A.S.; Ensslin, N.; Mayo, D.R.; Mercer, D.J.; Miller, M.C.; Russo, P.A.

    1998-12-01

    The results from simulations and laboratory experiments with boron-loaded plastic scintillating fibers as a nondestructive assay tool are presented. Single and multiclad fibers in three diameters of 0.25, 0.5, and 1 mm were examined for their application in neutron coincident counting. For this application, the simulation results show that various configurations of boro-loaded plastic scintillating fibers have a die-away time ({tau}) of 12 {micro}s with an efficiency ({var_epsilon}) of 50%. For a comparable efficiency, {sup 3}He proportional tubes have a typical die-away time of 50 {micro}s. The shortened die-away time can reduce the relative error for measurement of similar samples by up to 50%. Plastic scintillating fibers also offer flexible configurations with the potential to discriminate between signals from gamma-ray and neutron events. To date, the emphasis of the investigation has been the detection capability of plastic scintillating fibers for neutrons and gamma rays and evaluation of their ability to discriminate between the two events. Quantitative calculations and experiments have also been conducted to determine the light output, evaluate the noise,quantify light attenuation, and determine neutron detection efficiency. Current experimental data support the analytical results that boron-loaded plastic fibers can detect thermal neutrons with performance metrics that are comparable or better than those of {sup 3}He proportional tubes.

  19. Primary and secondary scintillation measurements in a Xenon Gas Proportional Scintillation Counter

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, L M P; Freitas, E D C; Monteiro, C M B; Santos, J M F dos [Instrumentation Centre, Physics Department, University of Coimbra, P-3004-516 Coimbra (Portugal); Ball, M; Gomez-Cadenas, J J; Yahlali, N [Instituto de Fisica Corpuscular, E-46071, Valencia (Spain); Nygren, D, E-mail: pancho@gian.fis.uc.p [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2010-09-15

    NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC. The detector requires excellent energy resolution, which can be achieved in a Xe TPC with electroluminescence readout. Hamamatsu R8520-06SEL photomultipliers are good candidates for the scintillation readout. The performance of this photomultiplier, used as VUV photosensor in a gas proportional scintillation counter, was investigated. Initial results for the detection of primary and secondary scintillation produced as a result of the interaction of 5.9 keV X-rays in gaseous xenon, at room temperature and at pressures up to 3 bar, are presented. An energy resolution of 8.0% was obtained for secondary scintillation produced by 5.9 keV X-rays. No significant variation of the primary scintillation was observed for different pressures (1, 2 and 3 bar) and for electric fields up to 0.8 V cm{sup -1} torr{sup -1} in the drift region, demonstrating negligible recombination luminescence. A primary scintillation yield of 81 {+-} 7 photons was obtained for 5.9 keV X-rays, corresponding to a mean energy of 72 {+-} 6 eV to produce a primary scintillation photon in xenon.

  20. Organic Scintillators in Nonproliferation Applications With a Hybridized Double-Pulse Rejection Technique

    Science.gov (United States)

    Bourne, Mark Mitchell

    Alternative detection technologies are crucial to meeting demand for neutron detectors, for the current production of He-3, which has been the classical neutron choice, is insufficient. Organic scintillators are a strong candidate as a He-3 alternative due to their high efficiency, fast timing properties, and capabilities for separately identifying gamma-rays and neutrons through pulse shape discrimination (PSD). However, the use of organic scintillators in environments with numerous gamma rays can be limited because overlapping gamma-ray events can be misclassified as neutron events during PSD. To solve this problem, a new, hybridized double-pulse cleaning technique, consisting of three separate cleaning algorithms, was developed. The technique removes gamma-ray double pulses while preserving as many neutron pulses as possible. This technique was applied to separate experiments of Cf-252 and a gamma-ray source when measuring at a 100-kHz count rate and a field of 1000 incident gamma rays per incident neutron. It was found that stilbene scintillators were capable of intrinsic neutron efficiencies between 15-19% when measuring bare Cf-252 and 13-17% when exposed to the gamma-ray field. Misclassification rates ranged from 10-6-10-5, a factor-of-5 better than both the EJ-309 liquid and BB3-5 plastic. Next, plutonium experiments were performed with stilbene to determine which cleaning algorithm was best for each sample. A clear correlation was found that related the correct method of cleaning to the measured gamma ray-to-neutron ratio. When the measured gamma ray-to-neutron ratio is 10 or below, the template cleaning algorithm is preferred, while the fractional and hybrid cleaning algorithms are preferred when the gamma ray-to-neutron ratio is 100 or greater. Discriminating neutron sources such as Cf-252 or AmLi from SNM samples such as plutonium is a top priority in nonproliferation. We demonstrate that time-correlated experiments, utilizing both PSD-capable plastic

  1. Development of a hard x-ray focal plane compton polarimeter: a compact polarimetric configuration with scintillators and Si photomultipliers

    Science.gov (United States)

    Chattopadhyay, T.; Vadawale, S. V.; Goyal, S. K.; Mithun, N. P. S.; Patel, A. R.; Shukla, R.; Ladiya, T.; Shanmugam, M.; Patel, V. R.; Ubale, G. P.

    2016-02-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm × 5 mm × 150 mm) which are read by Si Photomultiplier (SiPM). Use of the new generation SiPMs ensures the compactness of the instrument which is essential for the design of focal plane detectors. The expected sensitivity of such polarimetric configuration and complete characterization of the plastic scatterer, specially at lower energies have been discussed in [11, 13]. In this paper, we characterize the CsI(Tl) absorbers coupled to SiPM. We also present the experimental results from the fully assembled configuration of the Compton polarimeter.

  2. VHF scintillations, orientation of the anisotropy of F-region irregularities and direction of plasma convection in the polar cap

    Directory of Open Access Journals (Sweden)

    E. D. Tereshchenko

    2008-06-01

    Full Text Available Scintillation data recorded at the polar cap station Barentsburg are shown to occasionally exhibit two or more peaks in the latitudinal profiles of the amplitude dispersion. Comparison with concurrent SuperDARN radar convection maps indicates that multiple peaks occur when Barentsburg is located within the area of strong changes in the plasma flow direction. When parameters of the ionospheric irregularities are inferred from the scintillation data, the orientation of the irregularity anisotropy in a plane perpendicular to the magnetic field is found to coincide well with the E×B flow direction, individually for each peak of the scintillation data. The differences were found to be mostly less than 20° for a data set comprised of 104 events. The conclusion is made that analysis of scintillation data allows one to infer the direction of plasma flow with a certain degree of detail.

  3. Isotope Fractionation in Methane Reactions Studied by Gas Chromatography and Liquid Scintillation

    DEFF Research Database (Denmark)

    Andersen, Bertel Lohmann; Bidoglio, G.; Leip, A.

    1997-01-01

    Determination of C-14-marked methane by gas chromatography and liquid scintillation counting is shown to be useful in studies of isotope effects. Data on the specific activity is used to separate the contributions of (CH4)-C-14, and (CH4)-C-12 to the gas-chromatographic peak area. As an application...

  4. Scintillation-Induced Intermittency in SETI

    CERN Document Server

    Cordes, J M; Sagan, Carl Edward; Cordes, James M.; Sagan, Carl

    1997-01-01

    We consider interstellar scintillations as a cause of intermittency in radio signals from extraterrestrial intelligence (ETI). We demonstrate that scintillations are very likely to allow initial detections of narrowband signals from distant sources (> 100 pc), while making redetections improbable. We consider three models in order to assess the non-repeating, narrowband events found in recent SETI and to analyze large surveys in general: (I) Radiometer noise; (II) A population of constant Galactic sources undergoing interstellar scintillation,; and (III) Real, transient signals (or hardware errors) of either terrestrial or ET origin. We apply likelihood and Bayesian tests of the models to The Planetary Society/Harvard META data. We find that Models II and III are both highly preferred to Model I, but that Models II and III are about equally likely. Ruling out Model II in favor of Model III requires many more reobservations than were conducted in META *or* the reobservation threshold must be much lower than wa...

  5. Characterization of the new scintillator CLYC

    CERN Document Server

    Kui-Nian, Li; Qiang, Gui; Peng, Jin; Geng, Tian

    2016-01-01

    The first domestic inorganic scintillator CLYC was grown in Beijing Glass Research Instituteusing the vertical Bridgman method. In this work, we evaluated the performance of this new CLYC crystal in terms of gamma-ray energy resolution and pulse shape discrimination(PSD)capability between neutrons and gamma-rays. The decay times occurred throughdifferent scintillation mechanisms were achievedby fitting decay functions to the neutron and gamma-ray waveform structures. We found an energy resolution of 4.5% for 662-keV gamma-rays and efficient neutron/gamma PSD withFoM 2.6. Under gamma-ray excitation, there is ultrafast scintillation mechanism in CLYC, with a decay time about 2 ns,whereasthere is no evidence of ultrafast decay under thermal neutron excitation. This work contributes to promote domestic development of CLYC.

  6. Microfluidic Scintillation Detectors for High Energy Physics

    CERN Document Server

    Maoddi, Pietro; Mapelli, Alessandro

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

  7. Plastic Surgery Statistics

    Science.gov (United States)

    ... PSN PSEN GRAFT Contact Us News Plastic Surgery Statistics Plastic surgery procedural statistics from the American Society of Plastic Surgeons. Statistics by Year Print 2016 Plastic Surgery Statistics 2015 ...

  8. Near-infrared scintillation of liquid argon

    CERN Document Server

    Alexander, T; Lippincott, W H; Rubinov, P

    2016-01-01

    Since the 1970s it has been known that noble gases scintillate in the near infrared (NIR) region of the spectrum (0.7 $\\mu$m < $\\lambda$; < 1.5$\\mu$m). More controversial has been the question of the NIR light yield for condensed noble gases. We first present the motivation for using the NIR scintillation in liquid argon detectors, then briefly review early as well as more recent efforts and finally show encouraging preliminary results of a test performed at Fermilab.

  9. Quality study of the purified liquid scintillator

    Science.gov (United States)

    Konno, Y.; Nakajima, K.; Kibe, Y.

    2008-07-01

    We have been distilling the KamLAND liquid scintillator (LS) for the low energy solar neutrino observation. The distillation removes radioactive impurities from LS efficiently. We developed two types of high sensitivity radon detectors to monitor 222Rn contamination which causes a primary background source 210Pb. Their required sensitivity is several mBq/m3. The features and the measurement results of these detectors are presented. We also report the study of liquid scintillator properties after the distillation: attenuation length, light output and PPO density.

  10. Near-infrared scintillation of liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, T. [Fermilab; Escobar, C. O. [Campinas State U.; Lippincott, W. H. [Fermilab; Rubinov, P. [Fermilab

    2016-03-03

    Since the 1970s it has been known that noble gases scintillate in the near infrared (NIR) region of the spectrum (0.7 $\\mu$m < $\\lambda$; < 1.5$\\mu$m). More controversial has been the question of the NIR light yield for condensed noble gases. We first present the motivation for using the NIR scintillation in liquid argon detectors, then briefly review early as well as more recent efforts and finally show encouraging preliminary results of a test performed at Fermilab.

  11. International Colloquium on Scattering and Scintillation in Radio Astronomy

    CERN Document Server

    Coles, W A; Rickett, B J; Bird, M K; Efimov, A I; Samoznaev, L N; Rudash, V K; Chashei, I V; Plettemeier, D; Spangler, S R; Tokarev, Y; Belov, Y; Boiko, G; Komrakov, G; Chau, J; Harmon, J; Sulzer, M; Kojima, M; Tokumaru, M; Fujiki, K; Janardhan, P; Jackson, B V; Hick, P P; Buffington, A; Olyak, M R; Fallows, R A; Nechaeva, M B; Gavrilenko, V G; Gorshenkov, Yu N; Alimov, V A; Molotov, I E; Pushkarev, A B; Shanks, R; Tuccari, G; Lotova, N A; Vladimirski, K V; Obridko, V N; Gubenko, V N; Andreev, V E; Stinebring, D R; Gwinn, C; Lovell, J E J; Jauncey, D L; Senkbeil, C; Shabala, S; Bignall, H E; MacQuart, J P; Kedziora-Chudczer, L; Smirnova, T V; Malofeev, V M; Malov, O I; Tyulbashev, S A; Jessner, A; Sieber, W; Wielebinski, R; Scattering and Scintillation in Radio Astronomy

    2006-01-01

    Topics of the Colloquium: a) Interplanetary scintillation b) Interstellar scintillation c) Modeling and physical origin of the interplanetary and the interstellar plasma turbulence d) Scintillation as a tool for investigation of radio sources e) Seeing through interplanetary and interstellar turbulent media Ppt-presentations are available on the Web-site: http://www.prao.ru/conf/Colloquium/main.html

  12. Upconverting nanoparticles for optimizing scintillator based detection systems

    Science.gov (United States)

    Kross, Brian; McKisson, John E; McKisson, John; Weisenberger, Andrew; Xi, Wenze; Zom, Carl

    2013-09-17

    An upconverting device for a scintillation detection system is provided. The detection system comprises a scintillator material, a sensor, a light transmission path between the scintillator material and the sensor, and a plurality of upconverting nanoparticles particles positioned in the light transmission path.

  13. 21 CFR 892.1100 - Scintillation (gamma) camera.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scintillation (gamma) camera. 892.1100 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1100 Scintillation (gamma) camera. (a) Identification. A scintillation (gamma) camera is a device intended to image the distribution of radionuclides...

  14. Plastic bronchitis

    Directory of Open Access Journals (Sweden)

    Anil Kumar Singhi

    2015-01-01

    Full Text Available Plastic bronchitis, a rare but serious clinical condition, commonly seen after Fontan surgeries in children, may be a manifestation of suboptimal adaptation to the cavopulmonary circulation with unfavorable hemodynamics. They are ominous with poor prognosis. Sometimes, infection or airway reactivity may provoke cast bronchitis as a two-step insult on a vulnerable vascular bed. In such instances, aggressive management leads to longer survival. This report of cast bronchitis discusses its current understanding.

  15. Plastics recycling: challenges and opportunities.

    Science.gov (United States)

    Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

    2009-07-27

    Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3-4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it

  16. Robust GPS carrier tracking under ionospheric scintillation

    Science.gov (United States)

    Susi, M.; Andreotti, M.; Aquino, M. H.; Dodson, A.

    2013-12-01

    Small scale irregularities present in the ionosphere can induce fast and unpredictable fluctuations of Radio Frequency (RF) signal phase and amplitude. This phenomenon, known as scintillation, can degrade the performance of a GPS receiver leading to cycle slips, increasing the tracking error and also producing a complete loss of lock. In the most severe scenarios, if the tracking of multiple satellites links is prevented, outages in the GPS service can also occur. In order to render a GPS receiver more robust under scintillation, particular attention should be dedicated to the design of the carrier tracking stage, that is the receiver's part most sensitive to these types of phenomenon. This paper exploits the reconfigurability and flexibility of a GPS software receiver to develop a tracking algorithm that is more robust under ionospheric scintillation. For this purpose, first of all, the scintillation level is monitored in real time. Indeed the carrier phase and the post correlation terms obtained by the PLL (Phase Locked Loop) are used to estimate phi60 and S4 [1], the scintillation indices traditionally used to quantify the level of phase and amplitude scintillations, as well as p and T, the spectral parameters of the fluctuations PSD. The effectiveness of the scintillation parameter computation is confirmed by comparing the values obtained by the software receiver and the ones provided by a commercial scintillation monitoring, i.e. the Septentrio PolarxS receiver [2]. Then the above scintillation parameters and the signal carrier to noise density are exploited to tune the carrier tracking algorithm. In case of very weak signals the FLL (Frequency Locked Loop) scheme is selected in order to maintain the signal lock. Otherwise an adaptive bandwidth Phase Locked Loop (PLL) scheme is adopted. The optimum bandwidth for the specific scintillation scenario is evaluated in real time by exploiting the Conker formula [1] for the tracking jitter estimation. The performance

  17. Plasticity and beyond microstructures, crystal-plasticity and phase transitions

    CERN Document Server

    Hackl, Klaus

    2014-01-01

    The book presents the latest findings in experimental plasticity, crystal plasticity, phase transitions, advanced mathematical modeling of finite plasticity and multi-scale modeling. The associated algorithmic treatment is mainly based on finite element formulations for standard (local approach) as well as for non-standard (non-local approach) continua and for pure macroscopic as well as for directly coupled two-scale boundary value problems. Applications in the area of material design/processing are covered, ranging from grain boundary effects in polycrystals and phase transitions to deep-drawing of multiphase steels by directly taking into account random microstructures.

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

    CERN Document Server

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

    2010-01-01

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

  19. The SNO+ Scintillator Purification Plant and Projected Sensitivity to Solar Neutrinos in the Pure Scintillator Phase

    Science.gov (United States)

    Pershing, Teal; SNO+ Collaboration

    2016-03-01

    The SNO+ detector is a neutrino and neutrinoless double-beta decay experiment utilizing the renovated SNO detector. In the second phase of operation, the SNO+ detector will contain 780 tons of organic liquid scintillator composed of 2 g/L 2,5-diphenyloxazole (PPO) in linear alkylbenzene (LAB). In this phase, SNO+ will strive to detect solar neutrinos in the sub-MeV range, including CNO production neutrinos and pp production neutrinos. To achieve the necessary detector sensitivity, a four-part scintillator purification plant has been constructed in SNOLAB for the removal of ionic and radioactive impurities. We present an overview of the SNO+ scintillator purification plant stages, including distillation, water extraction, gas stripping, and metal scavenger columns. We also give the projected SNO+ sensitivities to various solar-produced neutrinos based on the scintillator plant's projected purification efficiency.

  20. Development of scintillator plates with high energy resolution for alpha particles made of GPS scintillator grains

    Science.gov (United States)

    Shimaoka, Takehiro; Kaneko, Junichi H.; Izaki, Kenji; Tsubota, Youichi; Higuchi, Mikio; Nishiyama, Shusuke

    2014-01-01

    A scintillator plate with high energy resolution was developed to produce an alpha particle monitor used in nuclear fuel reprocessing plants and mixed plutonium-uranium oxide (MOX) fuel plants. Grains of a Gd2Si2O7 (GPS) scintillator of several 10 to 550 μm were fixed on a glass substrate and were then mechanically polished. By increasing the size of scintillator grains and removing fine powders, the collected light yield and energy resolution for alpha particles were drastically improved. Energy resolution of 9.3% was achieved using average grain size of 91 μm. Furthermore, the ratios between counts in a peak and total counts were improved by more than 60% by the further increase of grain size and adoption of mechanically polished surfaces on both sides. Beta and gamma ray influences were suppressed sufficiently by the thin 100 μm scintillator plates.

  1. Liquid scintillator production for the NOvA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mufson, S., E-mail: mufson@indiana.edu [Indiana University, Bloomington, IN 47405 (United States); Baugh, B.; Bower, C. [Indiana University, Bloomington, IN 47405 (United States); Coan, T.E. [Southern Methodist University, Dallas, TX 75275 (United States); Cooper, J. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Corwin, L. [South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States); Karty, J.A. [Indiana University, Bloomington, IN 47405 (United States); Mason, P. [University of Tennessee, Knoxville, TN 37916 (United States); Messier, M.D. [Indiana University, Bloomington, IN 47405 (United States); Pla-Dalmau, A. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Proudfoot, M. [Renkert Oil, Morgantown, PA 19543 (United States)

    2015-11-01

    The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator as the active detector medium to its near and far detectors. The composition of this scintillator was specifically developed to satisfy NOvA's performance requirements. A rigorous set of quality control procedures was put in place to verify that the incoming components and the blended scintillator met these requirements. The scintillator was blended commercially in Hammond, IN. The scintillator was shipped to the NOvA detectors using dedicated stainless steel tanker trailers cleaned to food grade.

  2. Scintillation properties of YAG:Yb crystals

    CERN Document Server

    Antonini, P; Carugno, Giovanni; Iannuzzi, D

    2001-01-01

    We report on measurements of the light yield, emission spectrum, and time response of YAG:Yb crystals. The temperature dependence of light yield was investigated. Data show that YAG:Yb crystals are good scintillators, suitable for applications to neutrino detection and spectroscopy.

  3. Improved light yield of lead tungstate scintillators

    CERN Document Server

    Annenkov, A N; Hofstäetter, A; Korzhik, M V; Ligun, V; Lecoq, P; Missevitch, O V; Novotny, R; Peigneux, J P

    2000-01-01

    The application at medium and low energies of lead tungstate scintillators, so far optimized for the ECAL calorimeter of CMS for the future LHC, is strongly limited by their poor light yield. Suitable dopants like molybdenum and terbium can help to overcome this problem. Concepts, results, advantages and drawbacks of this approach are discussed. (11 refs).

  4. Optimization of Shielded Scintillator for Neutron Detection

    Science.gov (United States)

    Belancourt, Patrick; Morrison, John; Akli, Kramer; Freeman, Richard; High Energy Density Physics Team

    2011-10-01

    The High Energy Density Physics group is interested in the basic science of creating a neutron and gamma ray source. The neutrons and gamma rays are produced by accelerating ions via a laser into a target and creating fusion neutrons and gamma rays. A scintillator and photomultiplier tube will be used to detect these neutrons. Neutrons and photons produce ionizing radiation in the scintillator which then activates metastable states. These metastable states have both short and long decay rates. The initial photon count is orders of magnitude higher than the neutron count and poses problems for accurately detecting the neutrons due to the long decay state that is activated by the photons. The effects of adding lead shielding on the temporal response and signal level of the neutron detector will be studied in an effort to minimize the photon count without significant reduction to the temporal resolution of the detector. MCNP5 will be used to find the temporal response and energy deposition into the scintillator by adding lead shielding. Results from the simulations will be shown. Optimization of our scintillator neutron detection system is needed to resolve the neutron energies and neutron count of a novel neutron and gamma ray source.

  5. Progress in studying scintillator proportionality: Phenomenological model

    Energy Technology Data Exchange (ETDEWEB)

    Bizarri, Gregory; Cherepy, Nerine; Choong, Woon-Seng; Hull, Giulia; Moses, William; Payne, Sephen; Singh, Jai; Valentine, John; Vasilev, Andrey; Williams, Richard

    2009-04-30

    We present a model to describe the origin of non-proportional dependence of scintillator light yield on the energy of an ionizing particle. The non-proportionality is discussed in terms of energy relaxation channels and their linear and non-linear dependences on the deposited energy. In this approach, the scintillation response is described as a function of the deposited energy deposition and the kinetic rates of each relaxation channel. This mathematical framework allows both a qualitative interpretation and a quantitative fitting representation of scintillation non-proportionality response as function of kinetic rates. This method was successfully applied to thallium doped sodium iodide measured with SLYNCI, a new facility using the Compton coincidence technique. Finally, attention is given to the physical meaning of the dominant relaxation channels, and to the potential causes responsible for the scintillation non-proportionality. We find that thallium doped sodium iodide behaves as if non-proportionality is due to competition between radiative recombinations and non-radiative Auger processes.

  6. Assessment of scintillation proxy maps for a scintillation study during geomagnetically quiet and disturbed conditions over Uganda

    Science.gov (United States)

    Amabayo, Emirant B.; Jurua, Edward; Cilliers, Pierre J.

    2017-02-01

    The objective of this paper is demonstrate the validity and usefulness of scintillation proxies derived from IGS data, through its comparison with data from dedicated scintillation monitors and its application to GNSS scintillation patterns. The paper presents scintillation patterns developed by using data from the dedicated scintillation monitors of the scintillation network decision aid (SCINDA) network, and proxy maps derived from IGS GPS data for 2011 and 2012 over low latitude stations in Uganda. The amplitude and phase scintillation indicies (S4 and σΦ) were obtained from the Novatel GSV4004B ionospheric scintillation and total electron content (TEC) monitor managed by SCINDA at Makerere (0.340N, 32.570E). The corresponding IGS GPS proxy data were obtained from the receivers at Entebbe (0.040N, 32.440E) and Mbarara (0.600S, 30.740E). The derived amplitude (S4p) and phase (sDPR) scintillation proxy maps were compared with maps of S4 and σΦ during geomagnetic storms (moderate and strong) and geomagnetically quiet conditions. The scintillation patterns using S4 and σΦ and their respective proxies revealed similar diurnal and seasonal patterns of strong scintillation occurrence. The peaks of scintillation occurrence with mean values in the range 0.3 geomagnetically disturbed (moderate and strong) and quiet conditions over the Ugandan region. The results show that SCINDA and IGS based scintillation patterns reveal the same nighttime and seasonal occurrence of irregularities over Uganda irrespective of the geomagnetic conditions. Therefore, the amplitude and phase scintillation proxies presented here can be used to fill gaps in low-latitude data where there are no data available from dedicated scintillation receivers, irrespective of the geomagnetic conditions.

  7. Liquid scintillator production for the NOvA experiment

    CERN Document Server

    Mufson, S; Bower, C; Coan, T; Cooper, J; Corwin, L; Karty, J; Mason, P; Pla-Dalmau, A; Proudfoot, M

    2015-01-01

    The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator to its detectors as its active detector medium. The composition of the scintillator was developed to meet the requirements of the experiment. The scintillator was shipped to the NOvA near and far detectors using dedicated stainless steel tanker trailers. A rigorous set of quality control procedures were put in place to assure that the liquid scintillator was blended to satisfy the transparency, light yield, and conductivity requirements. The incoming components, the blended scintillator, and the scintillator in the transport tanker trailers were all qualified with these procedures, which ensured that the NOvA scintillator was high quality and met its performance requirements.

  8. Cross beam scintillations in non-Kolmogorov medium.

    Science.gov (United States)

    Baykal, Yahya

    2014-10-01

    For the collimated and focused cross beams, the on-axis scintillation index is evaluated when these beams propagate in weak non-Kolmogorov turbulence. In the limiting cases, our solution correctly reduces to the known Gaussian beam scintillations in Kolmogorov turbulence. For both the collimated and the focused cross beams, large power law exponent of the non-Kolmogorov turbulence is found to result in larger scintillations. Evaluating at a fixed power law exponent, the scintillation index of the collimated (focused) cross beam is higher (lower) than the collimated (focused) Gaussian beam scintillation index. When the asymmetry of the collimated (focused) cross beam increases, the scintillations increase (decrease). At a given cross beam configuration, change in the turbulence parameters varies the scintillations in the same manner for all power law exponent values.

  9. Global morphology of ionospheric F-layer scintillations using FS3/COSMIC GPS radio occultation data

    Science.gov (United States)

    Tsai, Lung-Chih; Su, Shin-Yi

    2016-07-01

    The FormoSat-3/ Constellation Observing System for Meteorology, Ionosphere and Climate (FS3/COSMIC) has been proven a successful mission on profiling and modeling of ionospheric electron density by the radio occultation (RO) technique. In this study we report FS3/COSMIC limb-viewing observations of the GPS L-band scintillation since mid 2006 and propose to study F-layer irregularity morphology. Generally the FS3/COSMIC has performed >1000 ionospheric RO observations per day. Most of these observations can provide limb-viewing profiles of S4 scintillation index at dual L-band frequencies. There are a few percentage of FS3/COSMIC RO observations having >0.08 S4 values on average. However, seven identified areas at Central Pacific Area (-20∘~ 20∘dip latitude, 160∘E~130∘W), South American Area (-20∘~ 20∘dip latitude, 100∘W~30∘W), African Area (-20∘~ 20∘dip latitude, 30∘W~50∘E), European Area (30∘~55∘N, 0∘~55∘E), Japan See Area (35∘~55∘N, 120∘~150∘E), Arctic Area (> 65∘dip latitude), and Antarctic Area (< -65∘dip latitude) have been designated to have much higher percentage of strong L-band RO scintillation. During these years in most of the last sunspot cycle from mid 2006 to end 2014 the climatology of scintillations, namely, its variations with each identified area, season, local time, magnetic activity and solar activity have been documented.

  10. Fast scintillation detectors for high-energy X-ray region

    Science.gov (United States)

    Kishimoto, Shunji; Nishikido, Fumihiko; Haruki, Rie; Shibuya, Kengo; Koshimizu, Masanori

    2012-03-01

    We have developed fast scintillation detectors for nuclear resonant scattering experiments using synchrotron radiation and a nuclear excited level existing in >30 keV. A fast x-ray detector using an organic-inorganic perovskite scintillator of phenethylamine lead bromide (PhE-PbBr4) had a dominant light emission with a fast decay time of 9.9 ns. An x-ray detector equipped with a 0.9-mm-thick PhE-PbBr4 crystal (size: ˜8 × 7 mm2) was used to detect nuclear resonant scattering in 61Ni (the first excited level: 67.41 keV; half-life: 5.3 ns). We could successfully record the decaying gamma rays emitted from 61Ni with a relatively high detection efficiency of 24%. A lead-doped plastic scintillator (NE142, Pb ˜5 wt% doped) had been known to have a faster decay time of 1.7 ns. Following a test of a single NE142 detector, a four-channel NE142 detector was fabricated and successfully applied to the synchrotron-radiation based Mössbauer spectroscopy experiment on 61Ni.

  11. Nano-Ceramic Coated Plastics

    Science.gov (United States)

    Cho, Junghyun

    2013-01-01

    Plastic products, due to their durability, safety, and low manufacturing cost, are now rapidly replacing cookware items traditionally made of glass and ceramics. Despite this trend, some still prefer relatively expensive and more fragile ceramic/glassware because plastics can deteriorate over time after exposure to foods, which can generate odors, bad appearance, and/or color change. Nano-ceramic coatings can eliminate these drawbacks while still retaining the advantages of the plastic, since the coating only alters the surface of the plastic. The surface coating adds functionality to the plastics such as self-cleaning and disinfectant capabilities that result from a photocatalytic effect of certain ceramic systems. These ceramic coatings can also provide non-stick surfaces and higher temperature capabilities for the base plastics without resorting to ceramic or glass materials. Titanium dioxide (TiO2) and zinc oxide (ZnO) are the candidates for a nano-ceramic coating to deposit on the plastics or plastic films used in cookware and kitchenware. Both are wide-bandgap semiconductors (3.0 to 3.2 eV for TiO2 and 3.2 to 3.3 eV for ZnO), so they exhibit a photocatalytic property under ultraviolet (UV) light. This will lead to decomposition of organic compounds. Decomposed products can be easily washed off by water, so the use of detergents will be minimal. High-crystalline film with large surface area for the reaction is essential to guarantee good photocatalytic performance of these oxides. Low-temperature processing (nano-ceramic coatings (TiO2, ZnO) on plastic materials (silicone, Teflon, PET, etc.) that can possess both photocatalytic oxide properties and flexible plastic properties. Processing cost is low and it does not require any expensive equipment investment. Processing can be scalable to current manufacturing infrastructure.

  12. Biodegradability of degradable plastic waste.

    Science.gov (United States)

    Agamuthu, P; Faizura, Putri Nadzrul

    2005-04-01

    Plastic waste constitutes the third largest waste volume in Malaysian municipal solid waste (MSW), next to putrescible waste and paper. The plastic component in MSW from Kuala Lumpur averages 24% (by weight), whereas the national mean is about 15%. The 144 waste dumps in the country receive about 95% of the MSW, including plastic waste. The useful life of the landfills is fast diminishing as the plastic waste stays un-degraded for more than 50 years. In this study the compostability of polyethylene and pro-oxidant additive-based environmentally degradable plastics (EDP) was investigated. Linear low-density polyethylene (LLDPE) samples exposed hydrolytically or oxidatively at 60 degrees C showed that the abiotic degradation path was oxidative rather than hydrolytic. There was a weight loss of 8% and the plastic has been oxidized as shown by the additional carbonyl group exhibited in the Fourier transform infra red (FTIR) Spectrum. Oxidation rate seemed to be influenced by the amount of pro-oxidant additive, the chemical structure and morphology of the plastic samples, and the surface area. Composting studies during a 45-day experiment showed that the percentage elongation (reduction) was 20% for McD samples [high-density polyethylene, (HDPE) with 3% additive] and LL samples (LLDPE with 7% additive) and 18% reduction for totally degradable plastic (TDP) samples (HDPE with 3% additive). Lastly, microbial experiments using Pseudomonas aeroginosa on carbon-free media with degradable plastic samples as the sole carbon source, showed confirmatory results. A positive bacterial growth and a weight loss of 2.2% for degraded polyethylene samples were evident to show that the degradable plastic is biodegradable.

  13. WIMPs search by exclusive measurements with thin multilayer NaI(Tl) scintillators (PICO-LON)

    CERN Document Server

    Fushimi, K; Yasuda, K; Kameda, Y; Koori, N; Nakayama, S; Ichihara, K; Nomachi, M; Umehara, S; Yoshida, S; Ejiri, H; Imagawa, K; Ito, H

    2006-01-01

    The WIMPs search project PICO-LON has been started with multilayer thin NaI(Tl) crystals. The thin (0.05cm) and wide area (5cmx5cm) NaI(Tl) crystals was successfully developed. The performances of thin NaI(Tl) scintillator was measured and they showed good energy resolution (20% at 60keV) and good position resolution (20% in 5cmx5cm wider area).

  14. Mitigation of Memory Effects in Beta Scintillation Cells for Radioactive Gas Detection

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, Carolyn E; McIntyre, Justin I; Antolick, Kathryn C; Carman, April J; Cooper, Matthew W; Hayes, James C; Heimbigner, Tom R; Hubbard, C W; Litke, Kevin E; Ripplinger, Mike D; Suarez, Reynold

    2005-08-31

    The Automated Radioxenon Sampler/Analyzer (ARSA) developed at PNNL measures the relative concentrations of xenon isotopes using a coincidence system. Previous tests of the ARSA system have shown that latent radioactivity remains in the plastic cells after evacuation of the gases, leading to a “memory effect” in which the background count rate is dependent on the sample history. The increased background results in lower detection sensitivity. Two possible solutions to the memory effect are explored in this work: depositing a thin layer of metal on the plastic cell (“metallization”), and using an inorganic scintillating cell composed of yttrium aluminum perovskite (YAP). In both cases, the presence of inorganic material at the surface is intended to inhibit the diffusion of gases into the cell walls.

  15. Nonproportionality of Scintillator Detectors: Theory and Experiment

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-08-17

    On the basis of nonproportionality data obtained for several scintillators, we have developed a theory to describe the carrier dynamics to fit the light yield versus electron energy. The theory of Onsager was adapted to explain how the carriers form excitons or sequentially arrive at the activators to promote the ion to an excited state, and the theory of Birks was employed to allow for exciton-exciton annihilation. We then developed a second theory to deduce the degradation in resolution that results from nonproportionality by evoking Landau fluctuations, which are essentially variations in the deposited energy density that occur as the high energy electron travels along its trajectory. In general there is good agreement with the data, in terms of fitting the nonproportionality curves and reproducing the literature values of nonproportionality's contribution to the scintillator resolution. With the resurgence of interest in developing scintillator detectors that have good energy resolution, an improved understanding of nonproportionality has become a crucial matter since it presents the fundamental limit to the achievable resolution. In order to hasten an improved understanding of scintillator nonproportionality, we have constructed an instrument referred to as SLYNCI (Scintillator Light Yield Nonproportionality Compton Instrument). This is a second-generation instrument to the original device developed by Valentine and coworkers, wherein several new principles of operation have served to increase the data rate by an order of magnitude as discussed in detail in References. In the present article, the focus is on a theory to describe the measured electron response, which is the light yield as a function of the electron energy. To do this, we account for transport of carriers and excitons, in terms of how they transfer their energy to the activators with competition from nonradiative decay pathways. This work builds on the original work of Murray and coworkers

  16. Recent Developments in Fast Neutron Detection and Multiplicity Counting with Liquid Scintillator

    Science.gov (United States)

    Nakae, L. F.; Chapline, G. F.; Glenn, A. M.; Kerr, P. L.; Kim, K. S.; Ouedraogo, S. A.; Prasad, M. K.; Sheets, S. A.; Snyderman, N. J.; Verbeke, J. M.; Wurtz, R. E.

    2011-12-01

    For many years, LLNL researchers have been developing time-correlated neutron detection techniques and algorithms for applications such as Arms Control, Threat Detection and Nuclear Material Assay. Many of the techniques have been developed specifically for the relatively low efficiency (a few percent) attainable by detector systems limited to man-portability. Historically, thermal neutron detectors (mainly 3He) were used, taking advantage of the high thermal neutron interaction cross sections. More recently, we have been investigating the use of fast neutron detection with liquid scintillators, inorganic crystals, and in the near future, pulse-shape discriminating plastics that respond over 1000 times faster (ns versus tens of μs) than thermal neutron detectors. Fast neutron detection offers considerable advantages since the inherent ns production timescales of spontaneous fission and neutron-induced fission are preserved and measured instead of being lost by thermalization required for thermal neutron detectors. We are now applying fast neutron technology to the safeguards regime in the form of fast portable digital electronics as well as faster and less hazardous scintillator formulations. Faster detector response times and sensitivity to neutron momentum show promise for measuring, differentiating, and assaying samples that have modest to very high count rates, as well as mixed fission sources like Cm and Pu. We report on measured results with our existing liquid scintillator array and progress on the design of a nuclear material assay system that incorporates fast neutron detection, including the surprising result that fast liquid scintillator detectors become competitive and even surpass the precision of 3He-based counters measuring correlated pairs in modest (kg) samples of plutonium.

  17. Recent Developments In Fast Neutron Detection And Multiplicity Counting With Verification With Liquid Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Nakae, L; Chapline, G; Glenn, A; Kerr, P; Kim, K; Ouedraogo, S; Prasad, M; Sheets, S; Snyderman, N; Verbeke, J; Wurtz, R

    2011-09-30

    For many years at LLNL, we have been developing time-correlated neutron detection techniques and algorithms for applications such as Arms Control, Threat Detection and Nuclear Material Assay. Many of our techniques have been developed specifically for the relatively low efficiency (a few percent) attainable by detector systems limited to man-portability. Historically, we used thermal neutron detectors (mainly {sup 3}He), taking advantage of the high thermal neutron interaction cross-sections. More recently, we have been investigating the use of fast neutron detection with liquid scintillators, inorganic crystals, and in the near future, pulse-shape discriminating plastics which respond over 1000 times faster (nanoseconds versus tens of microseconds) than thermal neutron detectors. Fast neutron detection offers considerable advantages, since the inherent nanosecond production time-scales of spontaneous fission and neutron-induced fission are preserved and measured instead of being lost by thermalization required for thermal neutron detectors. We are now applying fast neutron technology to the safeguards regime in the form of fast portable digital electronics as well as faster and less hazardous scintillator formulations. Faster detector response times and sensitivity to neutron momentum show promise for measuring, differentiating, and assaying samples that have modest to very high count rates, as well as mixed fission sources like Cm and Pu. We report on measured results with our existing liquid scintillator array, and progress on the design of a nuclear material assay system that incorporates fast neutron detection, including the surprising result that fast liquid scintillator detectors become competitive and even surpass the precision of {sup 3}He-based counters measuring correlated pairs in modest (kg) samples of plutonium.

  18. Plastics at sea (microplastics) : a potential risk for Hong Kong

    OpenAIRE

    Lee, Hiu-yan, Jessica; 李曉恩

    2013-01-01

    Plastics are cheap and convenient materials that are widely adopted in our daily applications. High production and consumption of plastics, however, are resulting in the issue of marine plastic pollution. Plastic debris is often divided into two categories: macroplastics and microplastics. Macroplastic is a well-known international problem to the world’s oceans, while microplastics often receive less attention. Many coastal areas and remote islands are suffering from plastic pollution. Marine...

  19. A large acceptance scintillator detector with wavelength shifting fibre readout for search of η-nucleus bound states

    Science.gov (United States)

    Betigeri, M. G.; Biswas, P. K.; Budzanowski, A.; Chatterjee, A.; Jahn, R.; Guha, S.; Hawranek, P.; Jain, B. K.; Jawale, S. B.; Jha, V.; Kilian, K.; Kliczewski, S.; Kirillov, Da.; Kirillov, Di.; Kolev, D.; Kravcikova, M.; Kutsarova, T.; Lesiak, M.; Lieb, J.; Machner, H.; Magiera, A.; Maier, R.; Martinska, G.; Nedev, S.; Piskunov, N.; Prasuhn, D.; Protić, D.; Ritman, J.; von Rossen, P.; Roy, B. J.; Shukla, P.; Sitnik, I.; Siudak, R.; Tsenov, R.; Ulicny, M.; Urban, J.; Vankova, G.; GEM Collaboration

    2007-07-01

    A large acceptance scintillator detector with wavelength shifting optical fibre readout has been designed and built to detect the decay particles of η-nucleus bound system (the so-called η-mesic nuclei), namely, protons and pions. The detector, named as ENSTAR detector, consists of 122 pieces of plastic scintillator of various shapes and sizes, which are arranged in a cylindrical geometry to provide particle identification, energy loss and coarse position information for these particles. A solid angle coverage of ˜95% of total 4 π is obtained in the present design of the detector. Monte Carlo phase space calculations performed to simulate the formation and decay of η-mesic nuclei suggest that its decay particles, the protons and pions are emitted with an opening angle of 150±20∘, and with energies in the range of 25-300 and 225-450 MeV, respectively. The detailed GEANT simulations show that ˜80 % of the decay particles (protons and pions) can be detected within ENSTAR. Several test measurements using alpha source, cosmic-ray muons, etc. have been carried out to study the response of ENSTAR scintillator pieces. The in-beam tests of fully assembled detector with proton beam of momentum 870 MeV/c from the Cooler synchrotron COSY have been performed. The test results show that the scintillator fibre design chosen for the detector has performed satisfactorily well. The present article describes the detector design, simulation studies, construction details and test results.

  20. A large acceptance scintillator detector with wavelength shifting fibre readout for search of {eta}-nucleus bound states

    Energy Technology Data Exchange (ETDEWEB)

    Betigeri, M.G.; Chatterjee, A.; Roy, B.J.; Shukla, P. [Nuclear Physics Div., BARC, Mumbai 400 085 (India); Biswas, P.K.; Guha, S.; Jawale, S.B. [Centre for Design and Manufacture, BARC, Mumbai 400 085 (India); Budzanowski, A. [Inst. of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland); Jahn, R. [Helmholtz-Inst. fuer Strahlen- und Kernphysik der Univ. Bonn, Bonn (Germany); Hawranek, P. [Inst. of Physics, Jagellonian Univ., Krakow (Poland); Jain, B.K. [Physics Dept., Mumbai Univ., Vidyanagari, Mumbai (India); Jha, V. [Nuclear Physics Div., BARC, Mumbai 400 085 (India)]. E-mail: vjha@barc.gov.in; Kilian, K.; Kirillov, Da.; Lesiak, M.; Maier, R.; Prasuhn, D.; Protic, D.; Ritman, J.; von Rossen, P. [Inst. fuer Kernphysik, Forschungszentrum Juelich, Juelich (Germany); Kliczewski, S. [Inst. of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland); Kirillov, Di.; Piskunov, N.; Sitnik, I. [Lab. for High Energies, JINR Dubna (Russian Federation); Kolev, D. [Physics Faculty, Univ. of Sofia, Sofia (Bulgaria); Kravcikova, M. [Technical Univ. Kosice, Kosice (Slovakia); Kutsarova, T. [Inst. of Nuclear Physics and Nuclear Energy, Sofia (Bulgaria); Lieb, J. [Physics Dept., George Mason Univ., Fairfax, VA (United States); Machner, H. [Inst. fuer Kernphysik, Forschungszentrum Juelich, Juelich (Germany)]|[Fachbereich Physik, Univ. Duisburg-Essen, Duisburg (Germany); Magiera, A. [Inst. of Physics, Jagellonian Univ., Krakow (Poland); Martinska, G.; Ulicny, M.; Urban, J. [P. J. Safarik Univ., Kosice, (Slovakia); Nedev, S. [Univ. of Chemical Technology and Metallurgy, Sofia (Bulgaria); Siudak, R. [Inst. of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland)]|[Inst. fuer Kernphysik, Forschungszentrum Juelich, Juelich (Germany); Tsenov, R. [Physics Faculty, Univ. of Sofia, Sofia (Bulgaria); Vankova, G. [Inst. fuer Kernphysik, Forschungszentrum Juelich, Juelich (Germany)]|[Physics Faculty, Univ. of Sofia, Sofia (Bulgaria)

    2007-07-21

    A large acceptance scintillator detector with wavelength shifting optical fibre readout has been designed and built to detect the decay particles of {eta}-nucleus bound system (the so-called {eta}-mesic nuclei), namely, protons and pions. The detector, named as ENSTAR detector, consists of 122 pieces of plastic scintillator of various shapes and sizes, which are arranged in a cylindrical geometry to provide particle identification, energy loss and coarse position information for these particles. A solid angle coverage of {approx}95% of total 4{pi} is obtained in the present design of the detector. Monte Carlo phase space calculations performed to simulate the formation and decay of {eta}-mesic nuclei suggest that its decay particles, the protons and pions are emitted with an opening angle of 150+/-20{sup a}t, and with energies in the range of 25-300 and 225-450MeV, respectively. The detailed GEANT simulations show that {approx}80 % of the decay particles (protons and pions) can be detected within ENSTAR. Several test measurements using alpha source, cosmic-ray muons, etc. have been carried out to study the response of ENSTAR scintillator pieces. The in-beam tests of fully assembled detector with proton beam of momentum 870MeV/c from the Cooler synchrotron COSY have been performed. The test results show that the scintillator fibre design chosen for the detector has performed satisfactorily well. The present article describes the detector design, simulation studies, construction details and test results.

  1. Overcoming maladaptive plasticity through plastic compensation

    Institute of Scientific and Technical Information of China (English)

    Matthew R.J.MORRIS; Sean M.ROGERS

    2013-01-01

    Most species evolve within fluctuating environments,and have developed adaptations to meet the challenges posed by environmental heterogeneity.One such adaptation is phenotypic plasticity,or the ability of a single genotype to produce multiple environmentally-induced phenotypes.Yet,not all plasticity is adaptive.Despite the renewed interest in adaptive phenotypic plasticity and its consequences for evolution,much less is known about maladaptive plasticity.However,maladaptive plasticity is likely an important driver of phenotypic similarity among populations living in different environments.This paper traces four strategies for overcoming maladaptive plasticity that result in phenotypic similarity,two of which involve genetic changes (standing genetic variation,genetic compensation) and two of which do not (standing epigenetic variation,plastic compensation).Plastic compensation is defined as adaptive plasticity overcoming maladaptive plasticity.In particular,plastic compensation may increase the likelihood of genetic compensation by facilitating population persistence.We provide key terms to disentangle these aspects of phenotypic plasticity and introduce examples to reinforce the potential importance of plastic compensation for understanding evolutionary change.

  2. Dosimetric characterization of the Exradin W1 plastic scintillator detector through comparison with an in-house developed scintillator system

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Behrens, Claus F.; Andersen, Claus E.

    2014-01-01

    method, but differing primarily in the signal detection hardware. The two systems were compared with respect to essential dosimetric properties, with the purpose of testing their performance under conditions less well discussed in the literature. A Farmer ionization chamber was used as the primary...... is therefore advised if using either system for measurements in large fields or under circumstances where the fibre irradiation geometry is unfavourable. Measurements of reference dose to water yielded differences up to 1.5% when compared with the Farmer ionization chamber for all investigated beam qualities...

  3. Primary and secondary scintillation measurements in a xenon Gas Proportional Scintillation Counter

    CERN Document Server

    Fernandes, L M P; Ball, M; Gómez-Cadenas, J J; Monteiro, C M B; Yahlali, N; Nygren, D; Santos, J M F dos

    2010-01-01

    NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC. The detector requires excellent energy resolution, which can be achieved in a Xe TPC with electroluminescence readout. Hamamatsu R8520-06SEL photomultipliers are good candidates for the scintillation readout. The performance of this photomultiplier, used as VUV photosensor in a gas proportional scintillation counter, was investigated. Initial results for the detection of primary and secondary scintillation produced as a result of the interaction of 5.9 keV X-rays in gaseous xenon, at room temperature and at pressures up to 3 bar, are presented. An energy resolution of 8.0% was obtained for secondary scintillation produced by 5.9 keV X-rays. No significant variation of the primary scintillation was observed for different pressures (1, 2 and 3 bar) and for electric fields up to 0.8 V cm-1 torr-1 in the drift region, demonstrating negligible recombination luminescence. A primary scinti...

  4. Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon

    CERN Document Server

    Cao, H; Avetisyan, R; Back, H O; Cocco, A G; DeJongh, F; Fiorillo, G; Galbiati, C; Grandi, L; Guardincerri, Y; Kendziora, C; Lippincott, W H; Love, C; Lyons, S; Manenti, L; Martoff, C J; Meng, Y; Montanari, D; Mosteiro, P; Olvitt, D; Pordes, S; Qian, H; Rossi, B; Saldanha, R; Sangiorgio, S; Siegl, K; Strauss, S Y; Tan, W; Tatarowicz, J; Walker, S; Wang, H; Watson, A W; Westerdale, S; Yoo, J

    2014-01-01

    We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC) to a low energy pulsed narrowband neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation and ionization yields for nuclear recoils with energies from 10.3 to 57.2 keV and for applied electric fields from 0 to 1000 V/cm. We also report the observation of an anti-correlation between scintillation and ionization from nuclear recoils, which is similar to the anti-correlation between scintillation and ionization from electron recoils. A comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field yielded a first evidence of sensitivity to direct...

  5. Central Tracking Detector Based on Scintillating Fibres

    CERN Multimedia

    2002-01-01

    Scintillating fibres form a reasonable compromise for central tracking detectors in terms of price, resolution, response time, occupancy and heat production. \\\\ \\\\ New fluorescents with large Stokes shifts have been produced, capable of working without wavelength shifters. Coherent multibundles have been developed to achieve high packing fractions. Small segments of tracker shell have been assembled and beam tests have confirmed expectations on spatial resolution. An opto-electronic delay line has been designed to delay the track patterns and enable coincidences with a first level trigger. Replacement of the conventional phosphor screen anode with a Si pixel chip is achieved. This tube is called ISPA-tube and has already been operated in beam tests with a scintillating fibres tracker. \\\\ \\\\ The aim of the proposal is to improve hit densities for small diameter fibres by increasing the fraction of trapped light, by reducing absorption and reflection losses, by reflecting light at the free fibre end, and by inc...

  6. Scintillating 99Tc Selective Ion Exchange Resins

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell Greenhalgh; Richard D. Tillotson

    2012-07-01

    Scintillating technetium (99Tc) selective ion exchange resins have been developed and evaluated for equilibrium capacities and detection efficiencies. These resins can be utilized for the in-situ concentration and detection of low levels of pertechnetate anions (99TcO4-) in natural waters. Three different polystyrene type resin support materials were impregnated with varying amounts of tricaprylmethylammonium chloride (Aliquat 336) extractant, several different scintillating fluors and wavelength shifters. The prepared resins were contacted batch-wise to equilibrium over a wide range of 99TcO4- concentrations in natural water. The measured capacities were used to develop Langmuir adsorption isotherms for each resin. 99Tc detection efficiencies were determined and up to 71.4 ± 2.6% was achieved with some resins. The results demonstrate that a low level detection limit for 99TcO4- in natural waters can be realized.

  7. Semiconductor High-Energy Radiation Scintillation Detector

    CERN Document Server

    Kastalsky, A; Spivak, B

    2006-01-01

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

  8. Neutron detection with single crystal organic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Zaitseva, N; Newby, J; Hamel, S; Carman, L; Faust, M; Lordi, V; Cherepy, N; Stoeffl, W; Payne, S

    2009-07-15

    Detection of high-energy neutrons in the presence of gamma radiation background utilizes pulse-shape discrimination (PSD) phenomena in organics studied previously only with limited number of materials, mostly liquid scintillators and single crystal stilbene. The current paper presents the results obtained with broader varieties of luminescent organic single crystals. The studies involve experimental tools of crystal growth and material characterization in combination with the advanced computer modeling, with the final goal of better understanding the relevance between the nature of the organic materials and their PSD properties. Special consideration is given to the factors that may diminish or even completely obscure the PSD properties in scintillating crystals. Among such factors are molecular and crystallographic structures that determine exchange coupling and exciton mobility in organic materials and the impurity effect discussed on the examples of trans-stilbene, bibenzyl, 9,10-diphenylanthracene and diphenylacetylene.

  9. Transparent Ceramic Scintillator Fabrication, Properties and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Cherepy, N J; Kuntz, J D; Roberts, J J; Hurst, T A; Drury, O B; Sanner, R D; Tillotson, T M; Payne, S A

    2008-08-24

    Transparent ceramics offer an alternative to single crystals for scintillator applications such as gamma ray spectroscopy and radiography. We have developed a versatile, scaleable fabrication method, using Flame Spray Pyrolysis (FSP) to produce feedstock which is readily converted into phase-pure transparent ceramics. We measure integral light yields in excess of 80,000 Ph/MeV with Cerium-doped Garnets, and excellent optical quality. Avalanche photodiode readout of Garnets provides resolution near 6%. For radiography applications, Lutetium Oxide offers a high performance metric and is formable by ceramics processing. Scatter in transparent ceramics due to secondary phases is the principal limitation to optical quality, and afterglow issues that affect the scintillation performance are presently being addressed.

  10. Scintillation Detectors in Experiments on Plasma Accelerators

    CERN Document Server

    Bystritsky, V M; Gerasimov, V V; Kublikov, R V; Nechaev, B A; Padalko, V M; Parzhitski, S S; Smirnov, V S; Wozniak, J

    2005-01-01

    The gating circuits for photomultipliers of scintillation detectors operating in powerful pulsed electromagnetic and nuclear radiation fields are investigated. PMTs with the jalousie-type dynode system and with the linear dynode system are considered. The basic gating circuits of the photomultipliers involving active and resistor high-voltage dividers are given. The results of the investigations are important for experiments in which it is necessary to discriminate in time the preceding background radiation and the process of interest.

  11. Nanophosphor composite scintillators comprising a polymer matrix

    Science.gov (United States)

    Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David

    2010-11-16

    An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.

  12. Improved Neutron Scintillators Based on Nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Dennis Friesel, PhD

    2008-06-30

    The development work conducted in this SBIR has so far not supported the premise that using nano-particles in LiFZnS:Ag foils improves their transparency to 420 (or other frequency) light. This conclusion is based solely on the light absorption properties of LiFZnS foils fabricated from nano- and from micro-particles. Furthermore, even for the case of the Gd{sub 2}O{sub 3} foils, the transmission of 420 nm light gained by using nano-particles all but disappears as the foil thickness is increased beyond about 0.2 mm, a practical scintillator thickness. This was not immediately apparent from the preliminary study since no foils thicker than about 0.04 mm were produced. Initially it was believed that the failure to see an improvement by using nano-particles for the LiFZnS foils was caused by the clumping of the particles in Toluene due to the polarity of the ZnS particles. However, we found, much to our surprise, that nano-particle ZnS alone in polystyrene, and in Epoxy, had worse light transmission properties than the micro-particle foils for equivalent thickness and density foils. The neutron detection measurements, while disappointing, are attributable to our inability to procure or fabricate Bulk Doped ZnS nanoparticles. The cause for the failure of nano-particles to improve the scintillation light, and hence improved neutron detection efficiency, is a fundamental one of light scattering within the scintillator. A consequence of PartTec's documentation of this is that several concepts for the fabrication of improved {sup 6}LiFZnS scintillators were formulated that will be the subject of a future SBIR submission.

  13. An easy method for Ra-226 determination in river waters by liquid-scintillation counting

    Science.gov (United States)

    Moreno, H. P.; Vioque, I.; Manjón, G.; García-Tenorio, R.

    1999-01-01

    226Ra activity concentration in river water was determined using a low background liquid scintillation counter. Radium was extracted from the samples as Ra-BaSO4 precipitate which, afterwards, was dissolved with EDTA in ammonia medium. Solution was transferred into a low potassium glass vial and then mixed with a scintillation cocktail. Two different scintillation cocktails were selected for comparison. Efficiency, recovery yield and α/β separation were studied with both liquid scintillation cocktails. One single measurement, made one month after radium separation, allows to calculate the226Ra concentration as well as to assess the presence of alpha contamination of the sample. In the case of negligible interferences,224Ra concentrations can be subsequently evaluated in the same sample by the measurement made just after chemical separation of radium. This method has been applied for the determination of226Ra and224Ra activity concentrations in river water collected from different locations along the Odiel river estuary area (South-west of Spain). The presence of chemical industry, the wastes of which are released into the river, could be connected with radium activity concentration enhancements in the water.

  14. Wavelength-shifting fiber readout of LaCl3 and LaBr3 scintillators

    Science.gov (United States)

    Case, Gary L.; Cherry, Michael L.; Stacy, J. Gregory; Welch, Christopher E.

    2005-08-01

    Inorganic scintillators such as NaI(Tl) and CsI(Na) have been used extensively in hard x-ray and low-energy gamma-ray imaging systems. Recently, a new generation of scintillators has been developed with properties that could greatly enhance the performance of such imaging systems. In particular, the lanthanum halides show great promise with increased light yield and peak emission at shorter wavelengths compared to NaI or CsI. Since these scintillators emit at relatively short wavelengths, wavelength-shifting fibers can be used which re-emit at wavelengths around 420 nm, providing a good match to bialkali photocathode response. Multi-anode photomultiplier tubes can be used to read out individual fibers from orthogonal layers to provide x-y position information, while energy measurements can be made by large area photomultiplier tubes. Such an arrangement potentially provides improved overall position and energy resolution and lower thresholds compared to imaging systems configured as standard NaI or CsI gamma cameras. We present measurements of the energy resolution obtained from lanthanum chloride (LaCl3) and lanthanum bromide (LaBr3) scintillators viewed both perpendicular to the axis and down the length of square multi-clad wavelength-shifting fibers. These results are compared to a standard NaI detector with wavelength-shifting fibers. The implications of these results for gamma-ray imaging will then be discussed.

  15. Performance study of Philips digital silicon photomultiplier coupled to scintillating crystals

    CERN Document Server

    Liu, Z.; Auffray, E.; Lecoq, P.; Paganoni, M.

    2016-01-01

    Silicon photomultipliers (SiPMs) and scintillators are often arranged in the shape of arrays in Positron Emission Tomography (PET) systems. Digital SiPMs provide signal readout in single photon avalanche diode (SPAD) level. From the photon count rate measurement of each SPAD cell of digital SiPM, we found that the output scintillating photons distribute in an area larger than the scintillator physical coupling area. Taking advantage of the possibility to enable/disable individual cells of the digital SiPM, a group of Lutetium-yttrium oxyorthosilicate (LYSO) crystals with different dimensions coupled to a digital SiPM was used to study the influence of using different SiPM active area on the number of photons detected, energy resolution and coincidence time resolution (CTR). For the same crystal coupled to the digital SiPM, the larger the active area of digital SiPM, the higher the number of photons detected. The larger active area of the digital SiPM also results in a better energy resolution after saturation...

  16. Boron-Loaded Silicone Rubber Scintillators

    CERN Document Server

    Bell, Z W; Maya, L; Sloop, F V J

    2003-01-01

    Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon respons...

  17. Chloride, bromide and iodide scintillators with europium

    Science.gov (United States)

    Zhuravleva, Mariya; Yang, Kan

    2016-09-27

    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  18. New scintillating crystals for PET scanners

    CERN Document Server

    Lecoq, P

    2002-01-01

    Systematic R&D on basic mechanism in inorganic scintillators, initiated by the Crystal Clear Collaboration at CERN 10 years ago, has contributed not to a small amount, to the development of new materials for a new generation of medical imaging devices with increased resolution and sensitivity. The first important requirement for a scintillator to be used in medical imaging devices is the stopping power for the given energy range of X and gamma rays to be considered, and more precisely the conversion efficiency. A high light yield is also mandatory to improve the energy resolution, which is essentially limited by the photostatistics and the electronic noise at these energies. A short scintillation decay time allows to reduce the dead time and therefore to increase the limiting counting rate. When all these requirements are fulfilled the sensitivity and image contrast are increased for a given patient dose, or the dose can be reduced. Examples of new materials under development by the Crystal Clear Collabor...

  19. Scintillators with potential to supersede lanthanum bromide

    Energy Technology Data Exchange (ETDEWEB)

    Cherepy, Nerine; Payne, Steven; Aszatlos, Steve; Hull, Giulia; Kuntz, J.; Niedermayr, Tom; Pimputkar, S.; Roberts, J.; Sanner, R.; Tillotson, T.; van Loef, Edger; Wilson, Cody; Shah, Kanai; Roy, U.; Hawrami, R.; Burger, Arnold; Boatner, Lynn; Choong, Woon-Seng; Moses, William

    2009-06-01

    New scintillators for high-resolution gamma ray spectroscopy have been identified, grown and characterized. Our development efforts have focused on two classes of high light yield materials: Europium-doped alkaline earth halides and Cerium-doped garnets. Of the halide single crystals we have grown by the Bridgman method - SrI{sub 2}, CaI{sub 2}, SrBr{sub 2}, BaI{sub 2} and BaBr{sub 2} - SrI{sub 2} is the most promising. SrI{sub 2}(Eu) emits into the Eu{sup 2+} band, centered at 435 nm, with a decay time of 1.2 {micro}s and a light yield of up to 115,000 photons/MeV. It offers energy resolution better than 3% FWHM at 662 keV, and exhibits excellent light yield proportionality. Transparent ceramics fabrication allows production of Gadolinium- and Terbium-based garnets which are not growable by melt techniques due to phase instabilities. While scintillation light yields of Cerium-doped ceramic garnets are high, light yield non-proportionality and slow decay components appear to limit their prospects for high energy resolution. We are developing an understanding of the mechanisms underlying energy dependent scintillation light yield non-proportionality and how it affects energy resolution. We have also identified aspects of optical design that can be optimized to enhance energy resolution.

  20. Separation of Scintillation and Cherenkov Lights in Linear Alkyl Benzene

    CERN Document Server

    Li, Mohan; Yeh, Minfang; Wang, Zhe; Chen, Shaomin

    2015-01-01

    To separate scintillation and Cherenkov lights in water-based liquid scintillator detectors is a desired feature for future neutrino and proton decay researches. Linear alkyl benzene (LAB) is one important ingredient of a water-based liquid scintillator being developed. In this paper we observed a good separation of scintillation and Cherenkov lights in an LAB sample. The rising and decay times of the scintillation light of the LAB were measured to be $(7.7\\pm3.0)\\ \\rm{ns}$ and $(36.6\\pm2.4)\\ \\rm{ns}$, respectively, while the full width [-3$\\sigma$, 3$\\sigma$] of the Cherenkov light was 12 ns dominated by the time resolution of our photomultiplier tubes. The light yield of the scintillation was measured to be $(1.01\\pm0.12)\\times10^3\\ \\rm{photons}/\\rm{MeV}$.

  1. Pulsar scintillations from corrugated reconnection sheets in the ISM

    CERN Document Server

    Pen, Ue-Li

    2013-01-01

    We show that surface waves along interstellar current sheets closely aligned with the line of sight lead to pulsar scintillation properties consistent with those observed. By contrast with previously considered scintillation drivers, our mechanism naturally produces the length and density scales of the ISM scattering lenses that are required to explain the magnitude and dynamical spectrum of the scintillations. In our picture, the parts of warm ionized interstellar medium that are responsible for the scintillations are relatively quiescent, with scintillation and scattering resulting from weak waves propagating along magnetic domain boundary current sheets, which are both expected from helicity conservation and have been observed in numerical simulations. The model quantitatively predicts the spacing and amplitudes of inverted parabolic arcs seen in Fourier-transformed dynamical spectra of strongly scintillating pulsars. Multi-frequency, multi-epoch low frequency VLBI observations can quantitatively test this...

  2. Metal-loaded organic scintillators for neutrino physics

    CERN Document Server

    Buck, Christian

    2016-01-01

    Organic liquid scintillators are used in many neutrino physics experiments of the past and present. In particular for low energy neutrinos when realtime and energy information are required, liquid scintillators have several advantages compared to other technologies. In many cases the organic liquid needs to be loaded with metal to enhance the neutrino signal over background events. Several metal loaded scintillators of the past suffered from chemical and optical instabilities, limiting the performance of these neutrino detectors. Different ways of metal loading are described in the article with a focus on recent techniques providing metal loaded scintillators that can be used under stable conditions for many years even in ton scale experiments. Applications of metal loaded scintillators in neutrino experiments are reviewed and the performance as well as the prospects of different scintillator types are compared.

  3. Metal-loaded organic scintillators for neutrino physics

    Science.gov (United States)

    Buck, Christian; Yeh, Minfang

    2016-09-01

    Organic liquid scintillators are used in many neutrino physics experiments of the past and present. In particular for low energy neutrinos when realtime and energy information are required, liquid scintillators have several advantages compared to other technologies. In many cases the organic liquid needs to be loaded with metal to enhance the neutrino signal over background events. Several metal loaded scintillators of the past suffered from chemical and optical instabilities, limiting the performance of these neutrino detectors. Different ways of metal loading are described in the article with a focus on recent techniques providing metal loaded scintillators that can be used under stable conditions for many years even in ton scale experiments. Applications of metal loaded scintillators in neutrino experiments are reviewed and the performance as well as the prospects of different scintillator types are compared.

  4. Measurements of proportional scintillation in liquid xenon using thin wires

    CERN Document Server

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

    2014-01-01

    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...

  5. A Model for the Secondary Scintillation Pulse Shape from a Gas Proportional Scintillation Counter

    CERN Document Server

    Kazkaz, Kareem

    2015-01-01

    Proportional scintillation counters (PSCs), both single- and dual-phase, can measure the scintillation (S1) and ionization (S2) channels from particle interactions within the detector volume. The signal obtained from these detectors depends first on the physics of the medium (the initial scintillation and ionization), and second how the physics of the detector manipulates the resulting photons and liberated electrons. In this paper we develop a model of the detector physics that incorporates event topology, detector geometry, electric field configuration, purity, optical properties of components, and wavelength shifters. We present an analytic form of the model, which allows for general study of detector design and operation, and a Monte Carlo model which enables a more detailed exploration of S2 events. This model may be used to study systematic effects in currents detectors such as energy and position reconstruction, pulse shape discrimination, event topology, dead time calculations, purity, and electric fi...

  6. Emulation workbench for position sensitive gaseous scintillation detectors

    CERN Document Server

    Pereira, L; Morozov, A; Solovov, V; Fraga, F A F

    2015-01-01

    Position sensitive detectors based on gaseous scintillation proportional counters with Anger-type readout are being used in several research areas such as neutron detection, search for dark matter and neutrinoless double beta decay. Design and optimization of such detectors are complex and time consuming tasks. Simulations, while being a powerful tool, strongly depend on the light transport models and demand accurate knowledge of many parameters, which are often not available. Here we describe an alternative approach based on the experimental evaluation of a detector using an isotropic point-like light source with precisely controllable light emission properties, installed on a 3D positioning system. The results obtained with the developed setup at validation conditions, when the scattered light is strongly suppressed, show good agreement with simulations.

  7. Emulation workbench for position sensitive gaseous scintillation detectors

    Science.gov (United States)

    Pereira, L.; Margato, L. M. S.; Morozov, A.; Solovov, V.; Fraga, F. A. F.

    2015-12-01

    Position sensitive detectors based on gaseous scintillation proportional counters with Anger-type readout are being used in several research areas such as neutron detection, search for dark matter and neutrinoless double beta decay. Design and optimization of such detectors are complex and time consuming tasks. Simulations, while being a powerful tool, strongly depend on the light transfer models and demand accurate knowledge of many parameters, which are often not available. Here we describe an alternative approach based on the experimental evaluation of a detector using an isotropic point-like light source with precisely controllable light emission properties, installed on a 3D positioning system. The results obtained with the developed setup at validation conditions, when the scattered light is strongly suppressed show good agreement with simulations.

  8. Investigation of Novel Glass Scintillators for Gamma Ray Detection

    Science.gov (United States)

    2013-02-01

    EMPLOYED BY YOUR ORGANIZATION. REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704·0188 The public roponin; burden for this collection of...efforts at LANL made significant progress during .this period. We have seen an optimization of both photo-luminescence and scintillation properties of...investigating Ce:GNS glass scintillators synthesized by our collaborators at LANL . The scintillation traces after ultrashort XUV excitation are shown

  9. Measurement of scintillation efficiency for nuclear recoils in liquid argon

    CERN Document Server

    Gastler, D; Hime, A; Stonehill, L C; Seibert, S; Klein, J; Lippincott, W H; McKinsey, D N; Nikkel, J A

    2010-01-01

    The scintillation light yield of liquid argon from nuclear recoils relative to electronic recoils has been measured as a function of recoil energy from 10 keVr up to 250 keVr. The scintillation efficiency, defined as the ratio of the nuclear recoil scintillation response to the electronic recoil response, is 0.25 \\pm 0.02 + 0.01(correlated) above 20 keVr.

  10. Rare-earth loaded liquid scintillator (for LENS experiment)

    CERN Document Server

    Barabanov, I R; Kornoukhov, V N; Yanovich, E A; Zatsepin, G T; Danilov, N A; Korpusov, G V; Kostukova, G V; Krylov, Y S; Yakshin, V V

    1999-01-01

    Rare-earth (Yb/Gd) complexes with neutral organophosphorus ligands are briefly discussed for their application in liquid scintillation technique. To evaluate the principal feasibility of rare-earth loaded scintillator, the ytterbium chloride complexes with tri-isoamylphosphine oxides were synthesized. Relative scintillation efficiency (RSE) for two Yb concentrations (78 and 88 g/L) was measured by means of the internal conversion exitation from Cs-137. The results obtained were 50 and 40% respectively.

  11. The Anti-Coincidence Detector for the GLAST Large Area Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Moiseev, A.A.; Hartman, R.C.; Ormes, J.F.; Thompson, D.J.; Amato, M.J.; Johnson, T.E.; Segal, K.N.; Sheppard, D.A.

    2007-03-23

    This paper describes the design, fabrication and testing of the Anti-Coincidence Detector (ACD) for the Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT). The ACD is LAT's first-level defense against the charged cosmic ray background that outnumbers the gamma rays by 3-5 orders of magnitude. The ACD covers the top and 4 sides of the LAT tracking detector, requiring a total active area of {approx}8.3 square meters. The ACD detector utilizes plastic scintillator tiles with wave-length shifting fiber readout. In order to suppress self-veto by shower particles at high gamma-ray energies, the ACD is segmented into 89 tiles of different sizes. The overall ACD efficiency for detection of singly charged relativistic particles entering the tracking detector from the top or sides of the LAT exceeds the required 0.9997.

  12. Strain gradient plasticity analysis of elasto-plastic contact between rough surfaces

    Science.gov (United States)

    Song, H.; Van der Giessen, E.; Liu, X.

    2016-11-01

    From a microscopic point of view, the real contact area between two rough surfaces is the sum of the areas of contact between facing asperities. Since the real contact area is a fraction of the nominal contact area, the real contact pressure is much higher than the nominal contact pressure, which results in plastic deformation of asperities. As plasticity is size dependent at size scales below tens of micrometers, with the general trend of smaller being harder, macroscopic plasticity is not suitable to describe plastic deformation of small asperities and thus fails to capture the real contact area and pressure accurately. Here we adopt conventional mechanism-based strain gradient plasticity (CMSGP) to analyze the contact between a rigid platen and an elasto-plastic solid with a rough surface. Flattening of a single sinusoidal asperity is analyzed first to highlight the difference between CMSGP and J2 isotropic plasticity. For the rough surface contact, besides CMSGP, pure elastic and J2 isotropic plasticity analysis is also carried out for comparison. In all cases, the contact area A rises linearly with the applied load, but with a different slope which implies that the mean contact pressures are different. CMSGP produces qualitative changes in the distributions of local contact pressures compared with pure elastic and J2 isotropic plasticity analysis, furthermore, bounded by the two.

  13. Lanthanide doped strontium-barium cesium halide scintillators

    Science.gov (United States)

    Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

    2015-06-09

    The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.

  14. Large-scale liquid scintillation detectors for solar neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Benziger, Jay B.; Calaprice, Frank P. [Princeton University Princeton, Princeton, NJ (United States)

    2016-04-15

    Large-scale liquid scintillation detectors are capable of providing spectral yields of the low energy solar neutrinos. These detectors require > 100 tons of liquid scintillator with high optical and radiopurity. In this paper requirements for low-energy neutrino detection by liquid scintillation are specified and the procedures to achieve low backgrounds in large-scale liquid scintillation detectors for solar neutrinos are reviewed. The designs, operations and achievements of Borexino, KamLAND and SNO+ in measuring the low-energy solar neutrino fluxes are reviewed. (orig.)

  15. Development of polystyrene-based scintillation materials and its mechanisms

    Science.gov (United States)

    Nakamura, Hidehito; Kitamura, Hisashi; Shinji, Osamu; Saito, Katashi; Shirakawa, Yoshiyuki; Takahashi, Sentaro

    2012-12-01

    Scintillation materials based on polystyrene (PS) have been investigated. Para-terphenyl was employed as a fluorescent molecule (fluor) that functions as a wavelength shifter. A clear increase in photon yield of the scintillation materials relative to the pure PS was observed, which cannot be explained by the conventional theory of scintillation mechanism. Furthermore, the photon yield increased with flour concentration in accordance with a power-law. Here we reveal the emergence of a luminescence of PS-based scintillation materials and demonstrate that their photon yields can be controlled by the fluor concentration.

  16. Plasmonic light yield enhancement of a liquid scintillator

    Science.gov (United States)

    Bignell, Lindsey J.; Mume, Eskender; Jackson, Timothy W.; Lee, George P.

    2013-05-01

    We demonstrate modifications to the light yield properties of an organic liquid scintillator due to the localization of the tertiary fluorophore component to the surface of Ag-core silica-shell nanoparticles. We attribute this enhancement to the near-field interaction of Ag nanoparticle plasmons with these fluor molecules. The scintillation light yield enhancement is shown to be equal to the fluorescence enhancement within measurement uncertainties. With a suitable choice of plasmon energy and scintillation fluor, this effect may be used to engineer scintillators with enhanced light yields for radiation detection applications.

  17. Ionospheric scintillation observations over Kenyan region - Preliminary results

    Science.gov (United States)

    Olwendo, O. J.; Xiao, Yu; Ming, Ou

    2016-11-01

    Ionospheric scintillation refers to the rapid fluctuations in the amplitude and phase of a satellite signal as it passes through small-scale plasma density irregularities in the ionosphere. By analyzing ionospheric scintillation observation datasets from satellite signals such as GPS signals we can study the morphology of ionospheric bubbles. At low latitudes, the diurnal behavior of scintillation is driven by the formation of large-scale equatorial density depletions which form one to two hours after sunset via the Rayleigh-Taylor instability mechanism near the magnetic equator. In this work we present ionospheric scintillation activity over Kenya using data derived from a newly installed scintillation monitor developed by CRIRP at Pwani University (39.78°E, 3.24°S) during the period August to December, 2014. The results reveal the scintillation activity mainly occurs from post-sunset to post-midnight hours, and ceases around 04:00 LT. We also found that the ionospheric scintillation tends to appear at the southwest and northwest of the station. These locations coincide with the southern part of the Equatorial Ionization Anomaly crest over Kenya region. The occurrence of post-midnight L-band scintillation events which are not linked to pre-midnight scintillation observations raises fundamental question on the mechanism and source of electric fields driving the plasma depletion under conditions of very low background electron density.

  18. Proton irradiation test to scintillator-directory-coupled CCD onboard FFAST

    Science.gov (United States)

    Nagino, Ryo; Nakajima, Hiroshi; Sadamoto, Masaaki; Sasaki, Masayuki; Tsunemi, Hiroshi; Hayashida, Kiyoshi; Anabuki, Naohisa; Kitamura, Hisashi; Uchihori, Yukio

    2013-09-01

    FFAST is a large area sky survey mission at hard X-ray region by using a spacecraft formation flying. It consists of two small satellites, a telescope satellite, carrying a multilayer super mirror, and a detector satellite, carrying scintillator-deposited CCDs (SD-CCDs). SD-CCD is the imaging device which realized sensitivity to 80 keV by pasting up a scintillator on CCD directly. Soft X-ray events are directly detected in the CCD. On the other hand, Hard X-ray events are converted to optical photons by the scintillator and then the CCD detects the photons. We have obtained the spectrum with 109Cd and successfully detected the events originated from the CsI. For a space use of a CCD, we have to understand aged deterioration of CCD in high radiative environments. In addition, in the case of SD-CCD, we must investigate the influence of radio-activation of a scintillator. We performed experiments of proton irradiation to the SD-CCD as space environmental tests of cosmic rays. The SD-CCD is irradiated with the protons with the energy of 100 MeV and neglected for about 150 hours. As a result, the derived CTI profile of SD-CCD is similarly to ones of XIS/Suzaku and NeXT4 CCD/ASTRO-H. In contrast, CTIs derived from the data within 4 hours after irradiation is 10 times or more larger than the ones after 150 hours. This may be due to influence of an annealing. We also report a performance study of SD-CCD, including the detection of scintillation events, before proton irradiation.

  19. Swarm GPS Receiver Performance under the Influence of Ionospheric Scintillation

    Science.gov (United States)

    Ren, Le; Schön, Steffen

    2016-04-01

    The Swarm mission launched on 22 November 2013 is ESA's first constellation of satellites to study the dynamics of the Earth's magnetic field and its interaction with the Earth system. This mission consists of three identical satellites in near-polar orbits , two flying almost side-by-side at an initial altitude of 460 km, the third flying in a higher orbit of about 530 km. Each satellite is equipped with a high precision 8-channels dual-frequency receiver for the precise orbit determination, which is also the essential fundament in order to take full advantage of the data information provided by this constellation, e.g. for the recovery of gravity field. The quality of the final orbit determination depends on the observation data from the receivers. In this contribution, we will analyze the performance of the Swarm on-board receivers, especially under the influence of ionospheric scintillation caused by ionospheric irregularities. This is a prerequisite for high quality satellite positioning as well as a sound study of the ionosphere. Ionospheric scintillation can lead to the phase disturbances, cycle slips or even loss of signal tracking. The RINEX observation data from Swarm Level 1b products are used to analyze the Swarm receiver performance. We will demonstrate the signal strength, code and phase noise, different linear combinations (geometry free, ionosphere free), as well as GDOP values for the 3 Swarm satellites. The first results show that the observation data are severely disturbed and the signals could be lost around the geomagnetic equator and geomagnetic poles where the ionosphere is active. The results also show that the receivers are more stable in those areas after the update in October 2015.

  20. Scintillator counters with multi-pixel avalanche photodiode readout for the ND280 detector of the T2K experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mineev, O. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation)]. E-mail: oleg@inr.ru; Afanasjev, A. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Bondarenko, G.; Golovin, V. [Center of Perspective Technology and Apparatus, 107076 Moscow (Russian Federation); Gushchin, E.; Izmailov, A.; Khabibullin, M.; Khotjantsev, A. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Kudenko, Yu. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Kurimoto, Y. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Kutter, T. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001 (United States); Lubsandorzhiev, B. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Mayatski, V. [AO Uniplast, 600016 Vladimir (Russian Federation); Musienko, Yu. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Nakaya, T.; Nobuhara, T. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Shaibonov, B.A.J.; Shaikhiev, A. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Taguchi, M. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Yershov, N. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Yokoyama, M. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2007-07-11

    The Tokai-to-Kamioka (T2K) experiment is a second generation long baseline neutrino oscillation experiment which aims at a sensitive search for {nu}{sub e} appearance. The main design features of the T2K near neutrino detectors located at 280m from the target are presented, and the scintillator counters are described. The counters are readout via WLS fibers embedded into S-shaped grooves in the scintillator from both ends by multi-pixel avalanche photodiodes operating in a limited Geiger mode. Operating principles and results of tests of photosensors with a sensitive area of 1mm{sup 2} are presented. A time resolution of 1.75ns, a spatial resolution of 9.9-12.4cm, and a detection efficiency for minimum ionizing particles of more than 99% were obtained for scintillator detectors in a beam test.

  1. Severe and localized GNSS scintillation at the poleward edge of the nightside auroral oval during intense substorm aurora

    CERN Document Server

    van der Meeren, Christer; Lorentzen, Dag A; Rietveld, Michael T; Clausen, Lasse B N

    2016-01-01

    In this paper we study how GPS, GLONASS, and Galileo navigation signals are compromised by strong irregularities causing severe phase scintillation ($\\mathit{\\sigma }_{\\phi }$ > 1) in the nightside high-latitude ionosphere during a substorm on 3 November 2013. Substorm onset and a later intensification coincided with polar cap patches entering the auroral oval to become auroral blobs. Using Global Navigation Satellite Systems (GNSS) receivers and optical data, we show severe scintillation driven by intense auroral emissions in the line of sight between the receiver and the satellites. During substorm expansion, the area of scintillation followed the intense poleward edge of the auroral oval. The intense auroral emissions were colocated with polar cap patches (blobs). The patches did not contain strong irregularities, neither before entering the auroral oval nor after the aurora had faded. Signals from all three GNSS constellations were similarly affected by the irregularities. Furthermore, two receivers space...

  2. AA, beam stopper with scintillator screen

    CERN Multimedia

    1980-01-01

    An insertable steel-plate beam stopper was located after nearly a full turn downstream of the injection point. It was fitted with a scintillator screen, a thin plate of Cr-doped alumina, imprinted with a grid and reference points. The screen was illuminated through a window and observed with a highly sensitive TV camera plus image intensifier. This allowed observation of beam position and size of a proton test beam and of the beam from the target, which consisted not only of antiprotons but contained as well electrons, pions and muons of the same momentum.

  3. Scintillating Fibre Calorimetry at the LHC

    CERN Multimedia

    2002-01-01

    Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. The lead/scintillating fibre calorimeter technique provides a fast signal response well matched to the LHC rate requirements. It can be made to give equal response for electrons and hadrons (compensation) with good electromagnetic and hadronic energy resolutions.\\\\ \\\\ The aim of this R&D proposal is to study in detail the aspects that are relevant for application of this type of calorimeter in an LHC environment, including its integration in a larger system of detectors, e.g.~projective geometry, radiation hardness, light detection, calibration and stability monitoring, electron/hadron separation.....

  4. Scintillating bolometers for Double Beta Decay search

    CERN Document Server

    Gironi, Luca

    2009-01-01

    In the field of Double Beta Decay (DBD) searches, the use of high resolution detectors in which background can be actively discriminated is very appealing. Scintillating bolometers containing a Double Beta Decay emitter can largely fulfill this very interesting possibility. In this paper we present the latest results obtained with CdWO4 and CaMoO4 crystals. Moreover we report, for the first time, a very interesting feature of CaMoO4 bolometers: the possibility to discriminate beta-gamma events from those induced by alpha particles thanks to different thermal pulse shape.

  5. Cherenkov and Scintillation Properties of Cubic Zirconium

    Science.gov (United States)

    Christl, M.J.; Adams, J.H.; Parnell, T.A.; Kuznetsov, E.N.

    2008-01-01

    Cubic zirconium (CZ) is a high index of refraction (n =2.17) material that we have investigated for Cherenkov counter applications. Laboratory and proton accelerator tests of an 18cc sample of CZ show that the expected fast Cherenkov response is accompanied by a longer scintillation component that can be separated by pulse shaping. This presents the possibility of novel particle spectrometers which exploits both properties of CZ. Other high index materials being examined for Cherenkov applications will be discussed. Results from laboratory tests and an accelerator exposure will be presented and a potential application in solar energetic particle instruments will be discussed

  6. Terbium-activated heavy scintillating glasses

    OpenAIRE

    Fu,J.; Kobayashi, M.; Parker, J.M.

    2008-01-01

    Tb-activated scintillating glasses with high Ln2O3 (Ln=Gd, Y, Lu) concentration up to 40mol% have been prepared. The effects of Ln3+ ions on the density, thermal properties, transmission and luminescence properties under both UV and X-ray excitation have been investigated. The glasses containing Gd2O3 or Lu2O3 exhibit a high density of more than 6.0g/cm3. Energy transfer from Gd3+ to Tb3+ takes place in Gd-containing glass and as a result the Gd-containing glass shows a light yield 2.5 times ...

  7. A multidetector scintillation camera with 254 channels

    DEFF Research Database (Denmark)

    Sveinsdottir, E; Larsen, B; Rommer, P

    1977-01-01

    A computer-based scintillation camera has been designed for both dynamic and static radionuclide studies. The detecting head has 254 independent sodium iodide crystals, each with a photomultiplier and amplifier. In dynamic measurements simultaneous events can be recorded, and 1 million total counts...... per second can be accommodated with less than 0.5% loss in any one channel. This corresponds to a calculated deadtime of 5 nsec. The multidetector camera is being used for 133Xe dynamic studies of regional cerebral blood flow in man and for 99mTc and 197 Hg static imaging of the brain....

  8. Simultaneous reconstruction of scintillation light and ionization charge produced by 511 keV photons in liquid xenon: Potential application to PET

    Energy Technology Data Exchange (ETDEWEB)

    Amaudruz, P. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: amaudruz@triumf.ca; Bryman, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada)], E-mail: bryman@phas.ubc.ca; Kurchaninov, L. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: kurchan@triumf.ca; Lu, P. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada)], E-mail: philipfl@phas.ubc.ca; Marshall, C. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: cammarsh@triumf.ca; Martin, J.P. [University of Montreal, CP 6128 Succursale Centre-Ville, Montreal, Quebec, H3C 3J7 (Canada)], E-mail: jpmartin@lps.umontreal.ca; Muennich, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: muennich@triumf.ca; Retiere, F. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: fretiere@triumf.ca; Sher, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: sher@triumf.ca

    2009-08-21

    In order to assess the performance of liquid xenon detectors for use in positron emission tomography we studied the scintillation light and ionization charge produced by 511 keV photons in a small prototype detector. Scintillation light was detected with large area avalanche photodiodes while ionization electrons were collected on an anode instrumented with low noise electronics after drifting up to 3 cm. Operational conditions were studied as a function of the electric field. Energy resolutions of <10% (FWHM) were achieved by combining the scintillation light and ionization charge signals. The relationship between scintillation light and ionization signals was investigated. An analysis of the sources of fluctuations was performed in order to optimize future detector designs.

  9. Study on Signal Processing Circuit Based on Scintillation Detector

    Institute of Scientific and Technical Information of China (English)

    YAO; Yong-gang; DENG; Chang-ming; LI; Jian-wei; XIAO; Cai-jin; ZHANG; Gui-ying; WANG; Ping-sheng; WANG; Xing-hua; JIN; Xiang-chun; HUA; Long; YUAN; Guo-jun; NI; Bang-fa

    2013-01-01

    Compared with silicon semiconductor detector,higher energy resolution and together with the high detection efficiency,big sensitive volume,good adaptability to environment and high sensitivityespecially in nature background environment are the characteristics of scintillation detector.The most widely applied scintillator includes inorganic crystals,of which sodium iodide is the favorite and

  10. TOF-PET detector concept based on organic scintillators

    CERN Document Server

    Moskal, P; Białas, P; Ciszewska, M; Czerwiński, E; Heczko, A; Kajetanowicz, M; Kapłon, Ł; Kochanowski, A; Konopka-Cupiał, G; Korcyl, G; Krzemień, W; Łojek, K; Majewski, J; Migdał, W; Molenda, M; Niedźwiecki, Sz; Pałka, M; Rudy, Z; Salabura, P; Silarski, M; Słomski, A; Smyrski, J; Zdebik, J; Zieliński, M

    2013-01-01

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

  11. Statistical characteristics of low-latitude ionospheric scintillation over China

    Science.gov (United States)

    Liu, Kangkang; Li, Guozhu; Ning, Baiqi; Hu, Lianhuan; Li, Hongke

    2015-03-01

    The Global Positioning System (GPS) L-band ionospheric scintillation produced by electron density irregularities in the ionospheric E- and F-regions, is mainly a low- and high-latitude phenomenon. In this study, the statistical behavior of GPS ionospheric scintillation over a Chinese low-latitude station Sanya (18.3°N, 109.6°E; dip lat: 12.8°N) has been investigated. A detailed study on the seasonal and solar activity dependence of scintillation occurrence during July 2004-December 2012 show that the amplitude scintillation pattern, with a maximum occurrence during equinox of solar maximum, agrees with plasma bubble observations by in situ satellites in this longitude. A few daytime periodic scintillation events are found during June solstice months of solar minimum. Interestingly, a significant equinoctial asymmetry of scintillation onset time is found in 2011-2012. The initiation of scintillation during September-October is on average earlier than that of March-April about 25 min. Meanwhile, the zonal drifts of irregularities estimated using two spatially separated GPS receivers over Sanya show a similar behavior during the two equinoxes, slowly decreasing from 150 m/s at post-sunset to 50 m/s near midnight. The possible mechanisms responsible for the occurrence characteristics of GPS scintillation over Sanya, and relevant aspects of the zonal drifts of the irregularities are discussed.

  12. Wavelength-shifting fiber signal readout from Transparent RUbber SheeT (TRUST) type LiCaAlF{sub 6} neutron scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Kenichi, E-mail: k-watanabe@nucl.nagoya-u.ac.jp [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Yamazaki, Takuya; Sugimoto, Dai; Yamazaki, Atsushi; Uritani, Akira; Iguchi, Tetsuo [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Fukuda, Kentaro; Ishidu, Sumito [Tokuyama Corporation, Shunan 745-8648 (Japan); Yanagida, Takayuki; Fujimoto, Yutaka [Kyushu Institute of Technology, Kita-kyushu 808-0196 (Japan)

    2015-06-01

    As an alternative to the standard {sup 3}He neutron detector, we are developing the Transparent RUbber SheeT type (TRUST) Eu doped LiCaAlF{sub 6} (Eu:LiCAF) scintillator. This type of neutron scintillator can easily be fabricated as a large area sheet. In order to take advantage of a large area detector, we try to readout scintillation photons using a wavelength-shifting fiber (WLSF) from a TRUST Eu:LiCAF scintillator. The TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm{sup 3} was mounted on the WLSF plate and the end of the WLSFs was connected with a PMT. In order to reject high pulse height events induced in the WLSFs, we applied the pulse shape discrimination technique. The gamma-ray intrinsic and neutron absolute detection efficiency is evaluated to be 8.8×10{sup −7} and 9×10{sup −3} cps/ng Cf (2 m) for the TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm{sup 3}.

  13. X-Ray Detector-on-Plastic with High Sensitivity Using Low Cost, Solution-Processed Organic Photodiodes

    NARCIS (Netherlands)

    Gelinck, G.H.; Kumar, A.; Moet, D.; Steen, J.L.P.J. van der; Breemen, A.J.J.M. van; Shanmugam, S.; Langen, A.; Gilot, J.; Groen, W.A.; Andriessen, H.A.J.M.; Simon, M.; Ruetten, W.; Douglas, A.U.; Raaijmakers, R.; Malinowski, P.E.; Myny, K.

    2016-01-01

    We made and characterized an X-ray detector on a 25-ìm-thick plastic substrate that is capable of medicalgrade performance. As an indirect conversion flat panel detector, it combined a standard scintillator with an organic photodetector (OPD) layer and oxide thin-film transistor backplane. Using sol

  14. Analysis of Ionospheric Scintillation Characteristics in Sub-Antarctica Region with GNSS Data at Macquarie Island

    Science.gov (United States)

    Guo, Kai; Liu, Yang; Zhao, Yan; Wang, Jinling

    2017-01-01

    Ionospheric scintillation has a great impact on radio propagation and electronic system performance, thus is extensively studied currently. The influence of scintillation on Global Navigation Satellite System (GNSS) is particularly evident, making GNSS an effective medium to study characteristics of scintillation. Ionospheric scintillation varies greatly in relation with temporal and spatial distribution. In this paper, both temporal and spatial characteristics of scintillation are investigated based on Macquarie Island’s GNSS scintillation data collected from 2011 to 2015. Experiments demonstrate that occurrence rates of amplitude scintillation have a close relationship with solar activity, while phase scintillation is more likely to be generated by geomagnetic activity. In addition, scintillation distribution behaviors related to elevation and azimuth angles are statistically analyzed for both amplitude and phase scintillation. The proposed work is valuable for a deeper understanding of theoretical mechanisms of ionospheric scintillation in this region, and provides a reference for GNSS applications in certain regions around sub-Antarctica. PMID:28085087

  15. An Experiment to Demonstrate Cherenkov / Scintillation Signal Separation

    CERN Document Server

    Caravaca, J; Land, B J; Wallig, J; Yeh, M; Gann, G D Orebi

    2016-01-01

    The ability to separately identify the Cherenkov and scintillation light components produced in scintillating mediums holds the potential for a major breakthrough in neutrino detection technology, allowing development of a large, low-threshold, directional detector with a broad physics program. The CHESS (CHErenkov / Scintillation Separation) experiment employs an innovative detector design with an array of small, fast photomultiplier tubes and state-of-the-art electronics to demonstrate the reconstruction of a Cherenkov ring in a scintillating medium based on photon hit time and detected photoelectron density. This paper describes the physical properties and calibration of CHESS along with first results. The ability to reconstruct Cherenkov rings is demonstrated in a water target, and a time precision of 338 +/- 12 ps FWHM is achieved. Monte Carlo based predictions for the ring imaging sensitivity with a liquid scintillator target predict an efficiency for identifying Cherenkov hits of 94 +/- 1% and 81 +/- 1...

  16. Optimization of light collection from crystal scintillators for cryogenic experiments

    Energy Technology Data Exchange (ETDEWEB)

    Danevich, F.A., E-mail: danevich@kinr.kiev.ua [Institute for Nuclear Research, MSP 03680, Kyiv (Ukraine); Kobychev, R.V. [Institute for Nuclear Research, MSP 03680, Kyiv (Ukraine); National Technical University of Ukraine “Kyiv Polytechnic Institute”, 03056 Kyiv (Ukraine); Kobychev, V.V. [Institute for Nuclear Research, MSP 03680, Kyiv (Ukraine); Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kraus, H. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Mikhailik, V.B. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Diamond Light Source, Harwell Science Campus, Didcot, OX11 0DE (United Kingdom); Mokina, V.M. [Institute for Nuclear Research, MSP 03680, Kyiv (Ukraine)

    2014-04-21

    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 promising detectors in experiments investigating neutrinoless double beta decay and dark matter. Energy resolutions and relative pulse amplitudes of scintillation detectors using ZnWO{sub 4} scintillation crystals of different shapes (cylinder ∅ 20×20 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.

  17. Screening Method of New Inorganic Scintillators for Photon Counting

    Science.gov (United States)

    Pritchard, Megan

    2004-10-01

    Inorganic scintillators play an important role in detection and visualization of ionizing radiation. A scintillator with both high light yield and fast response has yet to be found. These methods are useful in detector applications for homeland security and nuclear non-proliferation. New scintillators are necessary to improve radiation detectors for detection of fissile materials specifically when shielded. At ORNL, several new inorganic scintillators including various versions of ZnO, and SnO2 are being evaluated to determine light yield and decay times. Crystals are grown here, doped or painted with metals such as Al, Cd, Sn or Ga and measured. The photons emitted from a scintillator from a single incident alpha or neutron can be counted and graphed, allowing the luminosity and decay constants to be determined. The promising samples are also being evaluated for exact luminosity through spectroscopy.

  18. Screening Method of Inorganic Scintillators for Photon Counting

    Science.gov (United States)

    Pritchard, M.

    2004-10-01

    Inorganic scintillators play an important role in detection and visualization of ionizing radiation. A scintillator with both high light yield and fast response has yet to be found. These methods are useful in detector applications for homeland security and nuclear non-proliferation. New scintillators are necessary to improve radiation detectors for detection of fissile materials specifically when shielded. At ORNL, several new inorganic scintillators including various versions of ZnO, and SnO2 are being evaluated to determine light yield and decay times. Crystals are grown here, doped or painted with metals such as Al, Cd, Sn or Ga and measured. The photons emitted from a scintillator from a single incident alpha or neutron can be counted and graphed, allowing the luminosity and decay constants to be determined

  19. BL LAC PKSB1144-379 an extreme scintillator

    CERN Document Server

    Turner, R J; Shabala, S S; Blanchard, J; Lovell, J E J; McCallum, J N; Cimo, G

    2012-01-01

    Rapid variability in the radio flux density of the BL Lac object PKSB1144-379 has been observed at four frequencies, ranging from 1.5 to 15 GHz, with the VLA and the University of Tasmania's Ceduna antenna. Intrinsic and line of sight effects were examined as possible causes of this variability, with interstellar scintillation best explaining the frequency dependence of the variability timescales and modulation indices. This scintillation is consistent with a compact source 20-40 microarcseconds, or 0.15-0.3 pc in size. The inferred brightness temperature for PKSB1144-379 (assuming that the observed variations are due to scintillation) is 6.2e12 K at 4.9 GHz, with approximately 10 percent of the total flux in the scintillating component. We show that scintillation surveys aimed at identifying variability timescales of days to weeks are an effective way to identify the AGN with the highest brightness temperatures.

  20. Interstellar Refractive Scintillation and Intraday Polarization Angle Swings

    Institute of Scientific and Technical Information of China (English)

    Shan-Jie Qian; Xi-Zhen Zhang; A. Kraus

    2005-01-01

    Intraday polarization angle swings of ~180° observed in two sources (QSO 0917+624 and QSO 1150+812) are discussed in the framework of refractive interstellar scintillation by a continuous interstellar medium. Model-fits to the I-,Q- and U- light curves were made for both sources. It is shown that for the case of 0917+624 both the intraday intensity variations and the polarization angle swing of ~180° could be explained consistently in terms of a four-component model, which comprises one steady and two scintillating polarized components and one further non-polarized scintillating component. The polarization angle swing of ~180° observed in 1150+812, which occurred when the polarized flux density was almost constant, could not be explained in terms of refractive scintillation by a continuous medium and might be due to other mechanisms (e.g., scintillation by interstellar clouds).

  1. Visible scintillation photodetector device incorporating chalcopyrite semiconductor crystals

    Energy Technology Data Exchange (ETDEWEB)

    Stowe, Ashley C.; Burger, Arnold

    2017-04-04

    A photodetector device, including: a scintillator material operable for receiving incident radiation and emitting photons in response; a photodetector material coupled to the scintillator material operable for receiving the photons emitted by the scintillator material and generating a current in response, wherein the photodetector material includes a chalcopyrite semiconductor crystal; and a circuit coupled to the photodetector material operable for characterizing the incident radiation based on the current generated by the photodetector material. Optionally, the scintillator material includes a gamma scintillator material and the incident radiation received includes gamma rays. Optionally, the photodetector material is further operable for receiving thermal neutrons and generating a current in response. The circuit is further operable for characterizing the thermal neutrons based on the current generated by the photodetector material.

  2. Comparison of tropospheric scintillation prediction models of the Indonesian climate

    Science.gov (United States)

    Chen, Cheng Yee; Singh, Mandeep Jit

    2014-12-01

    Tropospheric scintillation is a phenomenon that will cause signal degradation in satellite communication with low fade margin. Few studies of scintillation have been conducted in tropical regions. To analyze tropospheric scintillation, we obtain data from a satellite link installed at Bandung, Indonesia, at an elevation angle of 64.7° and a frequency of 12.247 GHz from 1999 to 2000. The data are processed and compared with the predictions of several well-known scintillation prediction models. From the analysis, we found that the ITU-R model gives the lowest error rate when predicting the scintillation intensity for fade at 4.68%. However, the model should be further tested using data from higher-frequency bands, such as the K and Ka bands, to verify the accuracy of the model.

  3. Use and imaging performance of CMOS flat panel imager with LiF/ZnS(Ag) and Gadox scintillation screens for neutron radiography

    Science.gov (United States)

    Cha, B. K.; kim, J. Y.; Kim, T. J.; Sim, C.; Cho, G.; Lee, D. H.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2011-01-01

    In digital neutron radiography system, a thermal neutron imaging detector based on neutron-sensitive scintillating screens with CMOS(complementary metal oxide semiconductor) flat panel imager is introduced for non-destructive testing (NDT) application. Recently, large area CMOS APS (active-pixel sensor) in conjunction with scintillation films has been widely used in many digital X-ray imaging applications. Instead of typical imaging detectors such as image plates, cooled-CCD cameras and amorphous silicon flat panel detectors in combination with scintillation screens, we tried to apply a scintillator-based CMOS APS to neutron imaging detection systems for high resolution neutron radiography. In this work, two major Gd2O2S:Tb and 6LiF/ZnS:Ag scintillation screens with various thickness were fabricated by a screen printing method. These neutron converter screens consist of a dispersion of Gd2O2S:Tb and 6LiF/ZnS:Ag scintillating particles in acrylic binder. These scintillating screens coupled-CMOS flat panel imager with 25x50mm2 active area and 48μm pixel pitch was used for neutron radiography. Thermal neutron flux with 6x106n/cm2/s was utilized at the NRF facility of HANARO in KAERI. The neutron imaging characterization of the used detector was investigated in terms of relative light output, linearity and spatial resolution in detail. The experimental results of scintillating screen-based CMOS flat panel detectors demonstrate possibility of high sensitive and high spatial resolution imaging in neutron radiography system.

  4. Recycling of Plastic

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde

    2011-01-01

    Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like......, for example, gutters, window frames, car parts and transportation boxes have long lifetimes and thus appear as waste only many years after they have been introduced on the market. Plastic is constantly being used for new products because of its attractive material properties: relatively cheap, easy to form......, good strength and long durability. Recycling of plastic waste from production is well-established, while recycling of postconsumer plastic waste still is in its infancy. This chapter describes briefly how plastic is produced and how waste plastic is recycled in the industry. Quality requirements...

  5. Flotation separation of waste plastics for recycling-A review.

    Science.gov (United States)

    Wang, Chong-qing; Wang, Hui; Fu, Jian-gang; Liu, You-nian

    2015-07-01

    The sharp increase of plastic wastes results in great social and environmental pressures, and recycling, as an effective way currently available to reduce the negative impacts of plastic wastes, represents one of the most dynamic areas in the plastics industry today. Froth flotation is a promising method to solve the key problem of recycling process, namely separation of plastic mixtures. This review surveys recent literature on plastics flotation, focusing on specific features compared to ores flotation, strategies, methods and principles, flotation equipments, and current challenges. In terms of separation methods, plastics flotation is divided into gamma flotation, adsorption of reagents, surface modification and physical regulation.

  6. Proton recoils in organic liquid scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Juergen [Technische Universitaet Muenchen, Physik Department E15, Garching (Germany); Collaboration: LENA Working Group

    2012-07-01

    In liquid-scintillator detectors like the LENA (Low Energy Neutrino Astronomy) project, understanding the nature of proton recoils is vital. First of all concerning the observation of the diffuse Supernova anti {nu}{sub e} background with the inverse beta decay (IBD). This signature can be mimicked by the thermalization and capture of a knockout neutron originating from inelastic NC interactions of atmospheric neutrinos on {sup 12}C. However, with the help of pulse shape discrimination between the neutron-induced proton recoils and the prompt positron signal from the IBD, this background might be reduced effectively. Furthermore, elastic {nu}-p scattering is an important channel for neutrinos from a galactic core-collapse SN. In order to reconstruct the initial neutrino energy, the energy-dependent quenching factor of proton recoils has to be known. Therefore, a neutron scattering experiment at the Maier-Leibnitz-Laboratorium in Garching has been set up in order to understand the response of proton recoils in organic liquid scintillator.

  7. Scintillating Fibre Tracker Front-End Electronics for LHCb upgrade

    CERN Multimedia

    Comerma, A

    2014-01-01

    The LHCb detector will be upgraded during the next LHC shutdown in 2018/19. The tracker system will undergo major changes. Its components will be replaced by new technologies in order to cope with the increased hit occupancy and the higher radiation dose. A detector made of scintillating fibres read out by silicon photomultipliers (SiPM) is envisaged for this upgrade. Even if this technology has proven to achieve high efficiency and spatial resolution, its integration within a LHC experiment bears new challenges. The detector will consist of 12 planes of 5 to 6 layers of 250μm fibres stacked covering a total area of 5x6m^2 . The desired spacial resolution on the reconstructed hit is 100μm. SiPMs have been adapted to the detector geometry reducing the dead area between channels. A total of 64 channels are arranged in a single die with common cathode connection and channel size of 0.23x1.32mm^2 . Two dies are packaged together with only 0.25mm of dead area between them. Radiation tolerance of such devices is ...

  8. Scintillation and loss of signal lock from poleward moving auroral forms in the cusp ionosphere

    CERN Document Server

    Oksavik, K; Lorentzen, D A; Baddeley, L J; Moen, J

    2016-01-01

    We present two examples from the cusp ionosphere over Svalbard,where poleward moving auroral forms (PMAFs) are causing significant phase scintillation in signals from navigation satellites. The data were obtained using a combination of ground-based optical instruments and a newly installed multiconstellation navigation signal receiver at Longyearbyen. Both events affected signals from GPS and Global Navigation Satellite System (GLONASS). When one intense PMAF appeared, the signal from one GPS spacecraft also experienced a temporary loss of signal lock. Although several polar cap patches were also observed in the area as enhancements in total electron content, the most severe scintillation and loss of signal lock appear to be attributed to very intense PMAF activity. This shows that PMAFs are locations of strong ionospheric irregularities, which at times may cause more severe disturbances in the cusp ionosphere for navigation signals than polar cap patches.

  9. Plastic optical fibre sensor for in-vivo radiation monitoring during brachytherapy

    Science.gov (United States)

    Woulfe, P.; Sullivan, F. J.; Lewis, E.; O'Keeffe, S.

    2015-09-01

    An optical fibre sensor is presented for applications in real-time in-vivo monitoring of the radiation dose a cancer patient receives during seed implantation in Brachytherapy. The sensor is based on radioluminescence whereby radiation sensitive scintillation material is embedded in the core of a 1mm plastic optical fibre. Three scintillation materials are investigated: thallium-doped caesium iodide (CsI:Tl), terbium-doped gadolinium oxysulphide (Gd2O2S:Tb) and europium-doped lanthanum oxysulphide (La2O2S:Eu). Terbium-doped gadolinium oxysulphide was identified as being the most suitable scintillator and further testing demonstrates its measureable response to different activities of Iodine-125, the radio-active source commonly used in Brachytherapy for treating prostate cancer.

  10. Active Well Counting Using New PSD Plastic Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hausladen, Paul [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Newby, Jason [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McElroy, Robert Dennis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-11-01

    This report presents results and analysis from a series of proof-of-concept measurements to assess the suitability of segmented detectors constructed from Eljen EJ-299-34 PSD-plastic scintillator with pulse-shape discrimination capability for the purposes of quantifying uranium via active neutron coincidence counting. Present quantification of bulk uranium materials for international safeguards and domestic materials control and accounting relies on active neutron coincidence counting systems, such as the Active Well Coincidence Counter (AWCC) and the Uranium Neutron Coincidence Collar (UNCL), that use moderated He-3 proportional counters along with necessarily low-intensity 241Am(Li) neutron sources. Scintillation-based fast-neutron detectors are a potentially superior technology to the existing AWCC and UNCL designs due to their spectroscopic capability and their inherently short neutron coincidence times that largely eliminate random coincidences and enable interrogation by stronger sources. One of the past impediments to the investigation and adoption of scintillation counters for the purpose of quantifying bulk uranium was the commercial availability of scintillators having the necessary neutron-gamma pulse-shape discrimination properties only as flammable liquids. Recently, Eljen EJ-299-34 PSD-plastic scintillator became commercially available. The present work is the first assessment of an array of PSD-plastic detectors for the purposes of quantifying bulk uranium. The detector panel used in the present work was originally built as the focal plane for a fast-neutron imager, but it was repurposed for the present investigation by construction of a stand to support the inner well of an AWCC immediately in front of the detector panel. The detector panel and data acquisition of this system are particularly well suited for performing active-well fast-neutron counting of LEU and HEU samples because the active detector volume is solid, the 241Am(Li) interrogating

  11. 77 FR 54930 - Carlyle Plastics and Resins, Formerly Known as Fortis Plastics, A Subsidiary of Plastics...

    Science.gov (United States)

    2012-09-06

    ... Employment and Training Administration Carlyle Plastics and Resins, Formerly Known as Fortis Plastics, A... plastic parts. New information shows that Fortis Plastics is now called Carlyle Plastics and Resins. In... of Carlyle Plastics and Resins, formerly known as Fortis Plastics, a subsidiary of...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-05-01

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

  13. Weinig plastic in vissenmaag

    NARCIS (Netherlands)

    Foekema, E.M.

    2012-01-01

    Waar de magen van sommige zeevogels vol plastic zitten, lijken vissen in de Noordzee nauwelijks last te hebben van kunststofafval. Onderzoekers die plastic resten zochten in vissenmagen vonden ze in elk geval nauwelijks.

  14. Preparation and properties of scintillating glass doped with organic activators

    Institute of Scientific and Technical Information of China (English)

    ZHU Dong-mei; LUO Fa; ZHAO Hong-sheng; ZHOU Wan-cheng

    2006-01-01

    A series of scintillating glasses were developed by doping organic activators into low melting temperature glasses according to different ratios. The fluorescence spectra and the transmission spectra of some scintillating glasses were explored and the actual concentration organic in scintillating glass was estimated. The results show that it is feasible to prepare the scintillating glass by doing organic scintillating activators into the low-melting glasses. There are two main reasons for the weak optical properties of the scintillation glasses: one is that the actual concentration of organic activators doped in the glasses is very low,and the other is the existence of lots of defects formed in the scintillating glasses due to the evaporation of organic activator,lowering the transmission of glasses. The fluorescence emission peaks of the glasses move to a longer wavelength compared with those in organic matrixes. To increase the light output of the glass,the optical transmittance of the glasses must be improved and the concentration of activators in the glasses must be increased.

  15. Observational study of ionospheric irregularities and GPS scintillations associated with the 2012 tropical cyclone Tembin passing Hong Kong

    Science.gov (United States)

    Yang, Zhe; Liu, Zhizhao

    2016-05-01

    This study presents the ionospheric responses observed in Hong Kong to a Typhoon, namely, Tembin, from the aspects of the occurrence of ionospheric irregularities and scintillations, using Global Positioning System (GPS) observations from a ground-based GPS scintillation monitoring station in Hong Kong and from GPS receivers on board the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. The ionospheric irregularities and scintillations are characterized by the rate of total electron content variation index (ROTI) and the amplitude scintillation index S4, respectively. The typhoon Tembin formed over the western North Pacific during 18-30 August 2012 and approached Hong Kong during 24-27 August 2012 with the closest distance 290 km from Hong Kong at around 17 universal time (UT) on 25 August 2012. The ground-based observations indicate that in the nighttime period of 20:00-02:00 local time (LT = UT + 8 h) on 26 August when Tembin passed closely to Hong Kong, the ionospheric irregularities and scintillations of GPS signals were observed in the south of Hong Kong, over the area of 13°N ~ 23°N in latitude and 110°E ~ 120°E in longitude. From the COSMIC observations, it shows that the number of radio occultation scintillation events peaks on 26 August 2012 during the passage of Tembin. Without the presence of strong geomagnetic or solar activity, it is suspected that gravity waves might be generated in the lower atmosphere and likely seed the formation of ionospheric plasma irregularities. This work for the first time from Hong Kong observes the sign of coupling between the lower atmosphere and ionosphere in a tropical cyclone event, combining both ground- and space-based GPS observation data.

  16. Study on Growth and Optical, Scintillation Properties of Thallium Doped Cesium Iodide –Scintillator Crystal

    Directory of Open Access Journals (Sweden)

    B. Ravi

    2014-06-01

    Full Text Available Single crystal of Thallium doped cesium Iodide –Scintillator crystal was grown using vertical Bridgeman technique. The grown crystal was included for cutting and polishing for the characterization purpose and this crystal was studied by optical transmission properties, photo luminescence and thermally luminescence characteristics. Gamma-ray detectors were fabricated using the grown crystal that showed good linearity and nearly 7.5% resolution at 662 keV.

  17. Exercise and plasticize the brain

    DEFF Research Database (Denmark)

    Mala, Hana; Wilms, Inge

    Neuroscientific studies continue to shed light on brain’s plasticity and its innate mechanisms to recover. The recovery process includes re-wiring of the existing circuitry, establishment of new connections, and recruitment of peri-lesional and homologous areas in the opposite hemisphere. The pla......Neuroscientific studies continue to shed light on brain’s plasticity and its innate mechanisms to recover. The recovery process includes re-wiring of the existing circuitry, establishment of new connections, and recruitment of peri-lesional and homologous areas in the opposite hemisphere....... The plasticity of the brain can be stimulated and enhanced through training, which serves as a fundamental element of neurorehabilitative strategies. For instance, intensive cognitive and physical training promote the activation of processes that may help the brain to adapt to new conditions and needs. However...... neurorehabilitation is to understand and define how to stimulate the injured brain to elicit the desired adaptation. Research focuses on uncovering specific elements relevant for training planning and execution in order to create an environment that stimulates and maximizes the exploitation of the brain’s plastic...

  18. Scintillation properties of N2 and CF4 and performances of a scintillating ionization chamber

    Science.gov (United States)

    Lehaut, G.; Salvador, S.; Fontbonne, J.-M.; Lecolley, F.-R.; Perronnel, J.; Vandamme, Ch.

    2015-10-01

    In this work, we studied the emission yields, decay times and coincidence resolving times (CRT) of two gases, nitrogen (N2) and tetrafluoromethane (CF4), used for particle detection in the context of fission products measurement. The set-up was made of an ionization chamber and two photomultiplier tubes (PMTs) placed front-to-front on each side of the active zone of the chamber. Using the photomultiplier tubes, the number of photoelectrons (phe) converted at the photocathodes from the scintillation processes in each gas was quantified and the scintillation time spectra were recorded. A scintillation emission yield of 24 phe MeV-1 with a decay time of τd = 2.5 ns in N2, and 225 phe MeV-1 with τd = 6.2 ns for CF4, has been measured. With our set-up, the coincidence resolving time (σ values) between the two PMTs have been measured using alpha particles at 1.4 ns and 0.34 ns for N2 and CF4, respectively.

  19. Chemical Recycle of Plastics

    Directory of Open Access Journals (Sweden)

    Sara Fatima

    2014-11-01

    Full Text Available Various chemical processes currently prevalent in the chemical industry for plastics recycling have been discussed. Possible future scenarios in chemical recycling have also been discussed. Also analyzed are the effects on the environment, the risks, costs and benefits of PVC recycling. Also listed are the various types of plastics and which plastics are safe to use and which not after rcycle

  20. Extension of dynamic range in X-ray radiography using multi-color scintillation detector

    CERN Document Server

    Nittoh, K; Sakurai, T; Yoshida, T; Mochiki, K I

    2003-01-01

    A new imaging system using the multi-color scintillator Gd sub 2 O sub 2 S:Eu has been developed for the X-ray radiography. In this method a color Charge Coupled Device detects the weak blue and green photons associated with the transitions from the terms like sup 5 D sub 1 and sup 5 D sub 2 in the Eu-ions as well as the dominant red photons. As these transitions become appreciable and saturate at quite different intensity levels of the X-ray, we can realize a big extension of the dynamic range of the imaging almost by hundred times in comparison with the conventional monochromatic method. As a result, the new system makes it possible to take a clear image of any complex object, which consists of various parts of the different X-ray penetrability, from plastic to heavy metal, at a single shot.

  1. A Tungsten / Scintillating Fiber Electromagnetic Calorimeter Prototype for a High-Rate Muon g-2 Experiment

    CERN Document Server

    McNabb, R; Crnkovic, J D; Hertzog, D W; Kiburg, B; Kunkle, J; Thorsland, E; Webber, D M; Lynch, K R; 10.1016/j.nima.2009.01.007

    2009-01-01

    A compact and fast electromagnetic calorimeter prototype was designed, built, and tested in preparation for a next-generation, high-rate muon g-2 experiment. It uses a simple assembly procedure: alternating layers of 0.5-mm-thick tungsten plates and 0.5-mm-diameter plastic scintillating fiber ribbons. This geometry leads to a detector having a calculated radiation length of 0.69 cm, a Moliere radius of 1.73 cm, and a measured intrinsic sampling resolution term of (11.8\\pm1.1)/\\sqrt{E(GeV)}, in the range 1.5 to 3.5 GeV. The construction procedure, test beam results, and GEANT-4 comparative simulations are described.

  2. A Design of Scintillator Tiles Read Out by Surface-Mounted SiPMs for a Future Hadron Calorimeter

    CERN Document Server

    Liu, Yong; Caudron, Julien; Chau, Phi; Krause, Sascha; Masetti, Lucia; Schäfer, Ulrich; Spreckels, Rouven; Tapprogge, Stefan; Wanke, Rainer

    2015-01-01

    Precision calorimetry using highly granular sampling calorimeters is being developed based on the particle flow concept within the CALICE collaboration. One design option of a hadron calorimeter is based on silicon photomultipliers (SiPMs) to detect photons generated in plastic scintillator tiles. Driven by the need of automated mass assembly of around ten million channels stringently required by the high granularity, we developed a design of scintillator tiles directly coupled with surface-mounted SiPMs. A cavity is created in the center of the bottom surface of each tile to provide enough room for the whole SiPM package and to improve collection of the light produced by incident particles penetrating the tile at different positions. The cavity design has been optimized using a GEANT4-based full simulation model to achieve a high response to a Minimum Ionizing Particles (MIP) and also good spatial uniformity. The single-MIP response for scintillator tiles with an optimized cavity design has been measured usi...

  3. The theory of scintillation with applications in remote sensing

    CERN Document Server

    Rino, Charles

    2011-01-01

    "In order to truly understand data signals transmitted by satellite, one must understand scintillation theory in addition to well established theories of EM wave propagation and scattering. Scintillation is a nuisance in satellite EM communications, but it has stimulated numerous theoretical developments with science applications. This book not only presents a thorough theoretical explanation of scintillation, but it also offers a complete library of MATLAB codes that will reproduce the book examples. The library includes GPS coordinate manipulations, satellite orbit prediction, and earth mean magnetic field computations. The subect matter is for EM researchers; however, also theory is relevant to geophysics, acoustics, optics and astoronomy"--Provided by publisher.

  4. CsI(Tl) infrared scintillation light yield and spectrum

    CERN Document Server

    Belogurov, S; Carugno, Giovanni; Conti, E; Iannuzzi, D; Meneguzzo, Anna Teresa

    2000-01-01

    Infrared emission from CsI(Tl) excited by approx 70 keV electrons was detected with an InGaAs PIN photodiode. Some parameters of infrared scintillation were studied. The emission spectrum is located between 1.55 and 1.70 mu m with a maximum at 1.60 mu m. The light yield of infrared scintillation is (4.9+-0.3)x10 sup 3 photons/MeV. Infrared scintillation caused by 3 MeV alpha-particles is detected as well.

  5. Scintillation yield of liquid xenon at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ueshima, K. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan)], E-mail: ueshima@suketto.icrr.u-tokyo.ac.jp; Abe, K.; Iida, T.; Ikeda, M.; Kobayashi, K.; Koshio, Y.; Minamino, A.; Miura, M.; Moriyama, S. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Nakahata, M. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Nakajima, Y.; Ogawa, H.; Sekiya, H.; Shiozawa, M. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Suzuki, Y. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Takeda, A.; Takeuchi, Y.; Yamashita, M. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Kaneyuki, K. [Research Center for Cosmic Neutrinos, Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Doke, T. [Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8555 (Japan)] (and others)

    2008-09-01

    The intensity of scintillation light emission from liquid xenon at room temperature was measured. The scintillation light yield at 1{sup 0}C was measured to be 0.64{+-}0.02 (stat.) {+-}0.06 (sys.) of that at -100{sup 0}C. Using the reported light yield at -100{sup 0}C (46 photons/keV), the measured light yield at 1{sup 0}C corresponds to 29 photons/keV. This result shows that liquid xenon scintillator provides high light yield even at room temperature.

  6. Design and Prototyping of a High Granularity Scintillator Calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Zutshi, Vishnu [Northern Illinois Univ., DeKalb, IL (United States). Dept. of Physics

    2016-03-27

    A novel approach for constructing fine-granularity scintillator calorimeters, based on the concept of an Integrated Readout Layer (IRL) was developed. The IRL consists of a printed circuit board inside the detector which supports the directly-coupled scintillator tiles, connects to the surface-mount SiPMs and carries the necessary front-end electronics and signal/bias traces. Prototype IRLs using this concept were designed, prototyped and successfully exposed to test beams. Concepts and implementations of an IRL carried out with funds associated with this contract promise to result in the next generation of scintillator calorimeters.

  7. Ionization and scintillation of nuclear recoils in gaseous xenon

    Energy Technology Data Exchange (ETDEWEB)

    Renner, J., E-mail: jrenner@lbl.gov [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Gehman, V.M.; Goldschmidt, A.; Matis, H.S.; Miller, T.; Nakajima, Y.; Nygren, D.; Oliveira, C.A.B.; Shuman, D. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Álvarez, V. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Borges, F.I.G. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); Cárcel, S. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Castel, J.; Cebrián, S. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain); Cervera, A. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Conde, C.A.N. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); and others

    2015-09-01

    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 α-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.

  8. Ionization and scintillation of nuclear recoils in gaseous xenon

    CERN Document Server

    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

    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.

  9. Method for measuring multiple scattering corrections between liquid scintillators

    Science.gov (United States)

    Verbeke, J. M.; Glenn, A. M.; Keefer, G. J.; Wurtz, R. E.

    2016-07-01

    A time-of-flight method is proposed to experimentally quantify the fractions of neutrons scattering between scintillators. An array of scintillators is characterized in terms of crosstalk with this method by measuring a californium source, for different neutron energy thresholds. The spectral information recorded by the scintillators can be used to estimate the fractions of neutrons multiple scattering. With the help of a correction to Feynman's point model theory to account for multiple scattering, these fractions can in turn improve the mass reconstruction of fissile materials under investigation.

  10. Alpha counting and spectrometry using liquid scintillation methods

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, W J

    1986-01-01

    The material in this report is intended to be a practical introduction and guide to the use of liquid scintillation for alpha counting and spectrometry. Other works devoted to the development of the theory of liquid scintillation exist and a minimum of such material is repeated here. Much remains to be learned and many improvements remain to be made in the use of liquid scintillation for alpha counting and spectrometry. It is hoped that this modest work will encourage others to continue development in the field.

  11. Radon measurement using a liquid scintillation spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Taeko; Morishima, Hiroshige; Kawai, Hiroshi; Kondo, Sohei (Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.); Mifune, Masaki; Konishi, Masanobu; Shirai, Chiaki

    1992-12-01

    A convenient radon detecting device for the purpose of estimating natural radiation exposure is described. The [alpha] radioactivity of radon gas absorbed in fine active carbon particles exposed to air is measured with a liquid scintillation spectrometer (Packard-PICO-RAD system). Its detection limits are 2mBq/l in air and 0.5 Bq/l in water with an accuracy of about 10 %. Radon concentrations at Misasa hot springs in Tottori prefecture were measured using this method. They were 0.16 [approx] 7.7 Bq/l in a bath room and 0.057 [approx] 0.36 Bq/l outdoors. Radon concentrations of the hot springs were 82 [approx] 1,700 Bq/l. (author).

  12. Properties of Yb:YAG scintillators

    CERN Document Server

    Antonini, P; Bressi, G; Carugno, Giovanni; Santilli, P

    2002-01-01

    Relative light yield (LY) dependence on temperature for Yb:YAG crystals containing from 10% to 100% of Yb dopant is studied for gamma and alpha excitations. The maximum LY is achieved at 120 Kscintillation properties on concentration of Yb and purity is discussed.

  13. Bulk semiconducting scintillator device for radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Stowe, Ashley C.; Burger, Arnold; Groza, Michael

    2016-08-30

    A bulk semiconducting scintillator device, including: a Li-containing semiconductor compound of general composition Li-III-VI.sub.2, wherein III is a Group III element and VI is a Group VI element; wherein the Li-containing semiconductor compound is used in one or more of a first mode and a second mode, wherein: in the first mode, the Li-containing semiconductor compound is coupled to an electrical circuit under bias operable for measuring electron-hole pairs in the Li-containing semiconductor compound in the presence of neutrons and the Li-containing semiconductor compound is also coupled to current detection electronics operable for detecting a corresponding current in the Li-containing semiconductor compound; and, in the second mode, the Li-containing semiconductor compound is coupled to a photodetector operable for detecting photons generated in the Li-containing semiconductor compound in the presence of the neutrons.

  14. Sound and light from fractures in scintillators.

    Science.gov (United States)

    Tantot, A; Santucci, S; Ramos, O; Deschanel, S; Verdier, M-A; Mony, E; Wei, Y; Ciliberto, S; Vanel, L; Di Stefano, P C F

    2013-10-11

    Prompted by intriguing events observed in certain particle-physics searches for rare events, we study light and acoustic emission simultaneously in some inorganic scintillators subject to mechanical stress. We observe mechanoluminescence in Bi4Ge3O12, CdWO4, and ZnWO4, in various mechanical configurations at room temperature and ambient pressure. We analyze the temporal and amplitude correlations between the light emission and the acoustic emission during fracture. A novel application of the precise energy calibration of Bi4Ge3O12 provided by radioactive sources allows us to deduce that the fraction of elastic energy converted to light is at least 3×10(-5).

  15. Study Performance of Liquid Scintillation Fiber Detector

    CERN Document Server

    Zhang, Yongpeng; Lu, Haoqi; Zhang, Peng; Zhang, Chengcai; Yang, Changgen

    2016-01-01

    Liquid scintillator (LS) with optical fiber detector (LSOF detector) is a new type of detector, which has been applied in large-scale particle physics experiments in recent years. We were proposing LSOF detector as one option of top veto detector in Jiangmen Underground Neutrino Observatory (JUNO) experiment. The prototype detector was located in laboratory of the institute of high energy physics (IHEP). From prototype study, we found that the detector have a good performance and can satisfy JUNO requirement. The detection efficiency of cosmic ray muon is greater than 98% and can collect 58 photon electrons (p.e.) when muon is going through the detector. Further more, the relationship between p.e., material reflectivity and LS depth are studied. We also compared the data with Monte Carlo simulation, and they have a good agreement with each other.

  16. Spectroscopic neutron detection using composite scintillators

    Science.gov (United States)

    Jovanovic, I.; Foster, A.; Kukharev, V.; Mayer, M.; Meddeb, A.; Nattress, J.; Ounaies, Z.; Trivelpiece, C.

    2016-09-01

    Shielded special nuclear material (SNM), especially highly enriched uranium, is exceptionally difficult to detect without the use of active interrogation (AI). We are investigating the potential use of low-dose active interrogation to realize simultaneous high-contrast imaging and photofission of SNM using energetic gamma-rays produced by low-energy nuclear reactions, such as 11B(d,nγ)12C and 12C(p,p‧)12C. Neutrons produced via fission are one reliable signature of the presence of SNM and are usually identified by their unique timing characteristics, such as the delayed neutron die-away. Fast neutron spectroscopy may provide additional useful discriminating characteristics for SNM detection. Spectroscopic measurements can be conducted by recoil-based or thermalization and capture-gated detectors; the latter may offer unique advantages since they facilitate low-statistics and event-by-event neutron energy measurements without spectrum unfolding. We describe the results of the development and characterization of a new type of capture-gated spectroscopic neutron detector based on a composite of scintillating polyvinyltoluene and lithium-doped scintillating glass in the form of millimeter-thick rods. The detector achieves >108 neutron-gamma discrimination resulting from its geometric properties and material selection. The design facilitates simultaneous pulse shape and pulse height discrimination, despite the fact that no materials intrinsically capable of pulse shape discrimination have been used to construct the detector. Accurate single-event measurements of neutron energy may be possible even when the energy is relatively low, such as with delayed fission neutrons. Simulation and preliminary measurements using the new composite detector are described, including those conducted using radioisotope sources and the low-dose active interrogation system based on low-energy nuclear reactions.

  17. Effects of Plastic Film Mulching of Millet on Soil Moisture and Temperature in Semi-Arid Areas in South Ningxia of China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The effects of film mulching of millet on soil water content were studied in semi-arid areas in the Loess Plateau of South Ningxia, China. Different mulching methods including water micro-collecting farming (WF), water micro-collecting farming in winter fallow (WW), hole seeding on film (HF), hole seeding on film in winter fallow (HW) were compared to determine the effects of mulching methods on soil water collecting and conservation during millet growth periods of 2003-2004, as well as the variation tendency of water content after rainfall, output of millet and water use efficiency (WUE). The experimental results in the two successive years indicated that water micro-collecting farming had a better function of collecting water after rainfall, and side infiltrated water was stored under the ridges and the top layer 0-40 cm soil water changes were great. WF had obvious role in water collection and preservation of soil moisture. It effectively improved the water supply capacity by about 19.05% in the end of growth seasons. The storage of HW and WW increased by 24.9 and 7.1 mm compared with CK, and output of yield were obviously increased. Film mulching increased the yield of millet and enhanced water use efficiency (WUE). During different growth periods, WF exhibited better water storage function with lower water consumption, and demonstrated optimal social and ecological benefits.

  18. Effect of plastic film mulching on crop yield and nitrogen efficiency in semiarid areas.%半干旱地区地膜覆盖对作物产量和氮效率的影响

    Institute of Scientific and Technical Information of China (English)

    李世清; 李凤民; 宋秋华; 王俊

    2001-01-01

    The effect of plastic film mulching, water storage in soil profile before sowing, and nitrogen fertilization on crop yield and nitrogen efficiency was examined in this paper. The study site was on the cultivated lo,sial soil in semiarid areas with 415mm of annual rainfall and the test crop was spring wheat, Triticum aestivum. In order to study the effect of plastic film mulching, 4 levels of mulching were designed, including mulching of 0, 30 and 60 days after sowing and mulching over the whole growing period. The results showed that increase of soil water storage, plastic film mulching and nitrogen fertilization increased crop yield significantly(a< 0.01 ), and their effect followed in the order of nitrogen fertilization > increase of water storage>plastic film mulching. The effect of mulching on crop yield varied with water storage, nitrogen fertilization and mulching periods. When the water storage was low, there was no significant difference in crop yield between mulching and no mulching, although mulching increased crop yield slightly, and the nitrogen effi ciency was higher for no mulching and mulching 30 days. When the water storage was high, the difference between the yield of muching 60 days and no mulching was significant, but no difference in nitrogen efficiency was found for mulching 30 days, 60 days and over whole growing period. It was suggested that mulching over whole growing period was of less significance in practice.%在年降水量415mm的半干旱地区黄绵土上,以春小麦为供试作物进行大田试验,研究地膜覆盖进程(包括不覆膜、播种后覆膜30d、覆膜60d和全程覆膜)、底墒和施N对作物产量和N效率的影响.结果表明,增加底墒、地膜覆盖和施N均会显著增加作物产量和吸N量(α<0.01),其影响顺序为N肥>底墒>覆膜.覆膜对产量的效应因底、施N和覆膜进程而异.从平均看,在低底墒时,各种覆膜处理产量虽有增加,但与不

  19. Outflow structure of the quiet sun corona probed by spacecraft radio scintillations in strong scattering

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, Takeshi; Ando, Hiroki; Toda, Tomoaki; Nakamura, Masato [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Tokumaru, Munetoshi; Shiota, Daikou [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 484-8601 (Japan); Isobe, Hiroaki; Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471, Japan. (Japan); Miyamoto, Mayu [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Häusler, Bernd [Institut für Raumfahrttechnik, Universität der Bundeswehr München, D-85577 Neubiberg (Germany); Pätzold, Martin [Rheinisches Institut für Umweltforschung, Department Planetenforschung, Universität zu Köln, Aachener Strasse 209, D-50931 Köln (Germany); Nabatov, Alexander [The Institute of Radio Astronomy, National Academy of Science of Ukraine, Chervonoprapornaya, Strasse 4, Kharkov 61002 (Ukraine); Yaji, Kentaro [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Yamada, Manabu, E-mail: imamura.takeshi@jaxa.jp [Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1, Tsudanuma, Narashino, Chiba 275-0016 (Japan)

    2014-06-20

    Radio scintillation observations have been unable to probe flow speeds in the low corona where the scattering of radio waves is exceedingly strong. Here we estimate outflow speeds continuously from the vicinity of the Sun to the outer corona (heliocentric distances of 1.5-20.5 solar radii) by applying the strong scattering theory to radio scintillations for the first time, using the Akatsuki spacecraft as the radio source. Small, nonzero outflow speeds were observed over a wide latitudinal range in the quiet-Sun low corona, suggesting that the supply of plasma from closed loops to the solar wind occurs over an extended area. The existence of power-law density fluctuations down to the scale of 100 m was suggested, which is indicative of well-developed turbulence which can play a key role in heating the corona. At higher altitudes, a rapid acceleration typical of radial open fields is observed, and the temperatures derived from the speed profile show a distinct maximum in the outer corona. This study opened up a possibility of observing detailed flow structures near the Sun from a vast amount of existing interplanetary scintillation data.

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

    Science.gov (United States)

    Bok, Jan; Schauer, Petr

    2014-01-01

    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.

  1. Biodegradability of plastics.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

    2009-08-26

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  2. Plastic value chains

    DEFF Research Database (Denmark)

    Baxter, John; Wahlstrom, Margareta; Zu Castell-Rüdenhausen, Malin

    2014-01-01

    Optimizing plastic value chains is regarded as an important measure in order to increase recycling of plastics in an efficient way. This can also lead to improved awareness of the hazardous substances contained in plastic waste, and how to avoid that these substances are recycled. As an example......, plastics from WEEE is chosen as a Nordic case study. The project aims to propose a number of improvements for this value chain together with representatives from Nordic stakeholders. Based on the experiences made, a guide for other plastic value chains shall be developed....

  3. Journal of CHINA PLASTICS

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Journal of CHINA PLASTICS was authorized and approved by The State Committee of Science and Technology of China and The Bureau of News Press of China, and published by The China Plastics Processing Industry Association,Beijing Technology and Business University and The Institute of Plastics Processing and Application of Light Industry, distributed worldwide. Since its birth in 1987, CHINA PLASTICS has become a leading magazine in plastics industry in China, a national Chinese core journal and journal of Chinese scientific and technological article statistics. It is covered by CA.

  4. Plasticity of neonatal neuronal networks in very premature infants: Source localization of temporal theta activity, the first endogenous neural biomarker, in temporoparietal areas.

    Science.gov (United States)

    Routier, L; Mahmoudzadeh, M; Panzani, M; Azizollahi, H; Goudjil, S; Kongolo, G; Wallois, F

    2017-01-23

    Temporal theta slow-wave activity (TTA-SW) in premature infants is a specific signature of the early development of temporal networks, as it is observed at the turning point between non-sensory driven spontaneous local processing and cortical network functioning. The role in development and the precise location of TTA-SW remain unknown. Previous studies have demonstrated that preterms from 28 weeks of gestational age (wGA) are able to discriminate phonemes and voice, supporting the idea of a prior genetic structural or activity-dependent fingerprint that would prepare the auditory network to compute auditory information at the onset of thalamocortical connectivity. They recorded TTA-SW in 26-32 wGA preterms. The rate of TTA-SW in response to click stimuli was evaluated using low-density EEG in 30 preterms. The sources of TTA-SW were localized by high-density EEG using different tissues conductivities, head models and mathematical models. They observed that TTA-SW is not sensory driven. Regardless of age, conductivities, head models and mathematical models, sources of TTA-SW were located adjacent to auditory and temporal junction areas. These sources become situated closer to the surface during development. TTA-SW corresponds to spontaneous transient endogenous activities independent of sensory information at this period which might participate in the implementation of auditory, language, memory, attention and or social cognition convergent and does not simply represent a general interaction between the subplate and the cortical plate. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

  5. Glassy metallic plastics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper reports a class of bulk metallic glass including Ce-, LaCe-, CaLi-, Yb-, and Sr-based metallic glasses, which are regarded as glassy metallic plastics because they combine some unique properties of both plastics and metallic alloys. These glassy metallic plastics have very low glass transition temperature (Tg~25oC to 150oC) and low Young’s modulus (~20 GPa to 35 GPa). Similar to glassy plastics, these metallic plastics show excellent plastic-like deformability on macro-, micro- and even nano-scale in their supercooled liquid range and can be processed, such as elongated, compressed, bent, and imprinted at low temperatures, in hot water for instance. Under ambient conditions, they display such metallic properties as high thermal and electric conductivities and excellent mechanical properties and other unique properties. The metallic plastics have potential applications and are also a model system for studying issues in glass physics.

  6. Radiation scintillator embedded with a converting medium to detect and discriminate the four species of ionizing radiation

    Science.gov (United States)

    Pellegrin, Scott; Wilson, Chester G.

    2010-04-01

    A new nanoparticle loaded plastic scintillator embedded in a glass substrate detects and discriminates all species of radiation emitted from fissionable bomb making materials. The fast electron scintillating resin is doped with tailored charge conversion nanoparticles to produce characteristic optical pulses. The created optical pulses exit the detector, since the nanoparticles are appreciably smaller than the wavelength of light. Microsandblasting is used to etch deep cavities in the glass substrate forming independent optical paths. The doped resin is injected into the cavities and cured. A separate off-the-shelf PM tube linearly amplifies the created light pulse into a usable electrical signal. By using tailored nanoparticles, the physical mechanisms for converting different species of radiation into lower energy electrons allows for pulse height spectroscopy to discriminate between alpha, beta, gamma, and neutron radiation. A 90Sr source was used to test the beta detector, which is loaded with W. The drop in count rates versus distance was found to be similar to traditional detectors. The gamma detector loaded with Pb nanoparticles was tested with a 60Co source. The addition of Pb provided greater sensitivity to the gamma radiation. A 210Pl source was used to test the glass doped scintillator. The count rates remained fairly constant for varying distances since alpha particles tend to travel in straight paths until losing most of their initial energy. The 157Gd loaded scintillator was tested with an Am/Be source. 157Gd has the largest thermal neutron absorption cross section at 255,000 barns and releases a usable characteristic 72keV electron in 39% of the capture reactions.

  7. Inorganic Scintillators for Detector Systems Physical Principles and Crystal Engineering

    CERN Document Server

    AUTHOR|(CDS)2068219; Gektin, Alexander; Korzhik, Mikhail; Pédrini, Christian

    2006-01-01

    The development of new scintillators as components of modern detector systems is increasingly defined by the end user's needs. This book provides an introduction to this emerging topic at the interface of physics and materials sciences, with emphasis on bulk inorganic scintillators. After surveying the end user's needs in a vast range of applications, ranging from astrophysics to industrial R & D, the authors move on to review scintillating mechanisms and the properties of the most important materials used. A chapter on crystal engineering and examples of recent developments in the field of high-energy physics and medical imaging introduce the reader to the practical aspects. This book will benefit researchers and scientists working in academic and industrial R & D related to the development of scintillators.

  8. Inorganic scintillators for detector systems physical principles and crystal engineering

    CERN Document Server

    Lecoq, Paul; Korzhik, Mikhail

    2017-01-01

    This second edition features new chapters highlighting advances in our understanding of the behavior and properties of scintillators, and the discovery of new families of materials with light yield and excellent energy resolution very close to the theoretical limit. The book focuses on the discovery of next-generation scintillation materials and on a deeper understanding of fundamental processes. Such novel materials with high light yield as well as significant advances in crystal engineering offer exciting new perspectives. Most promising is the application of scintillators for precise time tagging of events, at the level of 100 ps or higher, heralding a new era in medical applications and particle physics. Since the discovery of the Higgs Boson with a clear signature in the lead tungstate scintillating blocks of the CMS Electromagnetic Calorimeter detector, the current trend in particle physics is toward very high luminosity colliders, in which timing performance will ultimately be essential to mitigating...

  9. Large liquid-scintillator trackers for neutrino experiments

    CERN Document Server

    Benussi, L; D'Ambrosio, N; Déclais, Y; Dupraz, J P; Fabre, Jean-Paul; Fanti, V; Forton, E; Frekers, D; Frenkel, A; Girerd, C; Golovkin, S V; Grégoire, G; Harrison, K; Jonkmans, G; Jonsson, P; Katsanevas, S; Kreslo, I; Marteau, J; Martellotti, G; Martínez, S; Medvedkov, A M; Moret, G; Niwa, K; Novikov, V; Van Beek, G; Penso, G; Vasilchenko, V G; Vuilleumier, J L; Wilquet, G; Zucchelli, P; Kreslo, I E

    2002-01-01

    Results are given on tests of large particle trackers for the detection of neutrino interactions in long-baseline experiments. Module prototypes have been assembled using TiO$_2$-doped polycarbonate panels. These were subdivided into cells of $\\sim 1$~cm$^2$ cross section and 6~m length, filled with liquid scintillator. A wavelength-shifting fibre inserted in each cell captured a part of the scintillation light emitted when a cell was traversed by an ionizing particle. Two different fibre-readout systems have been tested: an optoelectronic chain comprising an image intensifier and an Electron Bombarded CCD (EBCCD); and a hybrid photodiode~(HPD). New, low-cost liquid scintillators have been investigated for applications in large underground detectors. Testbeam studies have been performed using a commercially available liquid scintillator. The number of detected photoelectrons for minimum-ionizing particles crossing a module at different distances from the fibre readout end was 6 to 12 with the EBCCD chain and ...

  10. Rational design of binary halide scintillators via data mining

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Chang Sun [Department of Materials Science and Engineering, Iowa State University, 2220 Hoover Hall, Ames, Iowa 50011-2300 (United States); Rajan, Krishna, E-mail: krajan@iastate.edu [Department of Materials Science and Engineering, Iowa State University, 2220 Hoover Hall, Ames, Iowa 50011-2300 (United States)

    2012-07-11

    We introduce a new search strategy for the development of novel inorganic scintillators. For designing new scintillation host media having the improved properties, the potential candidate materials were chosen by using a chemical selection scheme based on a multi-dimensional similarity metric. For the quantitative assessment of the chosen materials, predictive models based on informatics were built by correlating a set of key parameters which reflect the features of the host materials with the performance of inorganic scintillators. The resulting design rules generated from the relationships serve as a guide to identify HfI{sub 4} and TaI{sub 5} as two new host lattices with high light yield. The method we have outlined here serves as a new computational template based statistical learning method to search for new inorganic scintillators with targeted properties.

  11. Reactor Neutrino Experiments with a Large Liquid Scintillator Detector

    CERN Document Server

    Kopp, J F; Merle, A; Rolinec, M

    2007-01-01

    We discuss several new ideas for reactor neutrino oscillation experiments with a Large Liquid Scintillator Detector. We consider two different scenarios for a measurement of the small mixing angle $\\theta_{13}$ with a mobile $\\bar{\

  12. A Scintillator Purification Plant and Fluid Handling System for SNO+

    CERN Document Server

    Ford, Richard J

    2015-01-01

    A large capacity purification plant and fluid handling system has been constructed for the SNO+ neutrino and double-beta decay experiment, located 6800 feet underground at SNOLAB, Canada. SNO+ is a refurbishment of the SNO detector to fill the acrylic vessel with liquid scintillator based on Linear Alkylbenzene (LAB) and 2 g/L PPO, and also has a phase to load natural tellurium into the scintillator for a double-beta decay experiment with 130Te. The plant includes processes multi-stage dual-stream distillation, column water extraction, steam stripping, and functionalized silica gel adsorption columns. The plant also includes systems for preparing the scintillator with PPO and metal-loading the scintillator for double-beta decay exposure. We review the basis of design, the purification principles, specifications for the plant, and the construction and installations. The construction and commissioning status is updated.

  13. Scintillation Velocity of PSR B0329+54

    Indian Academy of Sciences (India)

    R. X. Zhou; N. Wang; Z. Y. Liu; X. Liu

    2011-03-01

    We monitored PSR B0329+54 for one year using the Nanshan 25-m radio telescope, the scintillation velocity VISS shows evidence of systematic variation with the day of the year. States of interstellar medium (ISM) are discussed.

  14. Subnanosecond scintillation detector for high energy cosmic rays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The task objective is to develop a gamma ray scintillator technology with subnanosecond temporal resolution and the capability to withstand unprecedented rates and...

  15. Radio Scintillation due to Discontinuities in the Interstellar Plasma Density

    CERN Document Server

    Lambert, H; Lambert, Hendrik; Rickett, Barney

    1999-01-01

    We develop the theory of interstellar scintillation as caused by an irregular plasma having a power-law spatial density spectrum with a spectral exponent of 4 corresponding to a medium with abrupt changes in its density. An ``outer scale'' is included in the model representing the typical scale over which the density of the medium remains uniform. Such a spectrum could be used to model plasma shock fronts in supernova remnants or other plasma discontinuities. We investigate and develop equations for the decorrelation bandwidth of diffractive scintillations and the refractive scintillation index and compare our results with pulsar measurements. We consider both a medium concentrated in a thin layer and an extended irregular medium. We conclude that the discontinuity model gives satisfactory agreement for many diffractive measurements, in particular the VLBI meaurements of the structure function exponent between 5/3 and 2. However, it gives less satisfactory agreement for the refractive scintillation index than...

  16. Search of new scintillation materials for nuclear medicine application

    CERN Document Server

    Korzhik, M V

    2000-01-01

    Oxide crystals have a great potential to develop new advanced scintillation materials which are dense, fast, and bright. This combination of parameters, when combined to affordable price, gives a prospect for materials to be applied in nuclear medicine devices. Some of them have been developed for the last two decades along the line of rear-earth (RE) garnet (RE/sub 3/Al/sub 5/O/sub 12/) oxiorthosilicate (RE/sub 2/SiO/sub 5/) and perovskite (REAlO/sub 3/) crystals doped with Ce ions. Among recently developed oxide materials the lead tungstate scintillator (PWO) becomes the most used scintillation material in high energy physics experiments due to its application in CMS and ALICE experiments at LHC. In this paper we discuss scintillation properties of some new heavy compounds doped with Ce as well as light yield improvement of PWO crystals to apply them in low energy physics and nuclear medicine. (18 refs).

  17. Structured scintillators for X-ray imaging with micrometre resolution

    DEFF Research Database (Denmark)

    Olsen, Ulrik Lund; Schmidt, Søren; Poulsen, Henning Friis

    2009-01-01

    A 3D X-ray detector for imaging of 30–200 keV photons is described. It comprises a stack of semitransparent structured scintillators, where each scintillator is a regular array of waveguides in silicon, and with pores filled with CsI. The performance of the detector is described theoretically...... and explored in detail through simulations. The resolution of a single screen is shown to be determined only by the pitch, at least up to 100 keV. In comparison to conventional homogenous screens an improvement in efficiency by a factor 5–15 is obtainable. The cross-talk between screens in the 3D detector...... used regular scintillators with similar resolution an efficiency increase by a factor 4 has been found for the structured scintillator....

  18. Broadband Meter-Wavelength Observations of Ionospheric Scintillation

    CERN Document Server

    Fallows, R A; McKay, D; Vierinen, J; Virtanen, I I; Postila, M; Ulich, Th; Enell, C-F; Kero, A; Iinatti, T; Lehtinen, M; Orispää, M; Raita, T; Roininen, L; Turunen, E; Brentjens, M; Ebbendorf, N; Gerbers, M; Grit, T; Gruppen, P; Meulman, H; Norden, M; de Reijer, J-P; Schoenmakers, A; Stuurwold, K

    2015-01-01

    Intensity scintillations of cosmic radio sources are used to study astrophysical plasmas like the ionosphere, the solar wind, and the interstellar medium. Normally these observations are relatively narrow band. With Low Frequency Array (LOFAR) technology at the Kilpisj\\"arvi Atmospheric Imaging Receiver Array (KAIRA) station in northern Finland we have observed scintillations over a 3 octave bandwidth. ``Parabolic arcs'', which were discovered in interstellar scintillations of pulsars, can provide precise estimates of the distance and velocity of the scattering plasma. Here we report the first observations of such arcs in the ionosphere and the first broad-band observations of arcs anywhere, raising hopes that study of the phenomenon may similarly improve the analysis of ionospheric scintillations. These observations were made of the strong natural radio source Cygnus-A and covered the entire 30-250\\,MHz band of KAIRA. Well-defined parabolic arcs were seen early in the observations, before transit, and disapp...

  19. Improved Scintillator Materials For Compact Electron Antineutrino Detectors

    NARCIS (Netherlands)

    Dijkstra, Peter; Wortche, Heinrich J.; Browne, Wesley R.

    2012-01-01

    Recent developments provide new components holding the potential to improve the performance of liquid scintillation electron antineutrino detectors used as nuclear reactors monitors. Current systems raise issues regarding size, quantum efficiency, stability, and spatial resolution of the vertex dete

  20. Fast scintillation counters for the D0 muon system upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Baldin, B. [Fermi National Accelerator Lab., Batavia, IL (United States); Abramov, V.; Babintsev, V. [and others

    1999-08-01

    The design and main parameters of the completely redesigned D0 Forward Angle Muon System (FAMUS: 1.0 < {vert_bar}{eta}{vert_bar} < 2.0) for the next high luminosity Tevatron Collider run are reported. Results of the studies of trigger scintillation counters based on fast scintillator Bicron 404A and WLS bars SOFZ-105 are presented. The authors report about results of test beam studies of prototype counters including minimum ionizing particles detection efficiency, time resolution and amplitude response. Radiation ageing of scintillating materials for the doses up to 1 Mrad, phototubes magnetic shielding in the fields of up to 700 G and ageing of phototubes are presented. All tests show robustness of scintillation counters as triggering detector of the new muon system for a long period.

  1. Biological degradation of plastics: a comprehensive review.

    Science.gov (United States)

    Shah, Aamer Ali; Hasan, Fariha; Hameed, Abdul; Ahmed, Safia

    2008-01-01

    Lack of degradability and the closing of landfill sites as well as growing water and land pollution problems have led to concern about plastics. With the excessive use of plastics and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. Awareness of the waste problem and its impact on the environment has awakened new interest in the area of degradable polymers. The interest in environmental issues is growing and there are increasing demands to develop material which do not burden the environment significantly. Biodegradation is necessary for water-soluble or water-immiscible polymers because they eventually enter streams which can neither be recycled nor incinerated. It is important to consider the microbial degradation of natural and synthetic polymers in order to understand what is necessary for biodegradation and the mechanisms involved. This requires understanding of the interactions between materials and microorganisms and the biochemical changes involved. Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. This paper reviews the current research on the biodegradation of biodegradable and also the conventional synthetic plastics and also use of various techniques for the analysis of degradation in vitro.

  2. Research to Operations of Ionospheric Scintillation Detection and Forecasting

    Science.gov (United States)

    Jones, J.; Scro, K.; Payne, D.; Ruhge, R.; Erickson, B.; Andorka, S.; Ludwig, C.; Karmann, J.; Ebelhar, D.

    Ionospheric Scintillation refers to random fluctuations in phase and amplitude of electromagnetic waves caused by a rapidly varying refractive index due to turbulent features in the ionosphere. Scintillation of transionospheric UHF and L-Band radio frequency signals is particularly troublesome since this phenomenon can lead to degradation of signal strength and integrity that can negatively impact satellite communications and navigation, radar, or radio signals from other systems that traverse or interact with the ionosphere. Although ionospheric scintillation occurs in both the equatorial and polar regions of the Earth, the focus of this modeling effort is on equatorial scintillation. The ionospheric scintillation model is data-driven in a sense that scintillation observations are used to perform detection and characterization of scintillation structures. These structures are then propagated to future times using drift and decay models to represent the natural evolution of ionospheric scintillation. The impact on radio signals is also determined by the model and represented in graphical format to the user. A frequency scaling algorithm allows for impact analysis on frequencies other than the observation frequencies. The project began with lab-grade software and through a tailored Agile development process, deployed operational-grade code to a DoD operational center. The Agile development process promotes adaptive promote adaptive planning, evolutionary development, early delivery, continuous improvement, regular collaboration with the customer, and encourage rapid and flexible response to customer-driven changes. The Agile philosophy values individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and responding to change over following a rigid plan. The end result was an operational capability that met customer expectations. Details of the model and the process of

  3. Oxygen quenching in LAB based liquid scintillator and nitrogen bubbling

    CERN Document Server

    Hua-Lin, Xiao

    2009-01-01

    Oxygen quenching effect in Linear Alkl Benzne (LAB) based liquid scintillator (LAB+3g/L POPOP+ 15 mg Bis--MSB) was studied by measuring the light yield as the function of nitrogen bubbling time. it shows that the light yield of fully purged liquid scintillator would increase of nearly 11% in room temperature and room atmosphere pressure. A simple model of nitrogen bubbling was built to describe the relationship between relative light yield (oxygen quenching factor) and bubbling time.

  4. A Gas Proportional Scintillation Counter with krypton filling

    Science.gov (United States)

    Monteiro, C. M. B.; Mano, R. D. P.; Barata, E. C. G. M.; Fernandes, L. M. P.; Freitas, E. D. C.

    2016-12-01

    A Gas Proportional Scintillation Counter filled with pure krypton was studied. Energy resolution below 10% for 5.9-keV X-rays was obtained with this prototype. This value is much better than the energy resolution obtained with proportional counters or other MPGDs with krypton filling. The krypton electroluminescence scintillation and ionisation thresholds were found to be about 0.5 and 3.5 kV cm-1bar-1, respectively.

  5. Secondary scintillation in Ar-CF$_4$ mixtures

    CERN Document Server

    Beschi, Andrea

    2015-01-01

    In order to build a optical time projection chamber that can be used as a tracking detector, it is necessary to study the scintillation proprieties of gases in order to optimize the light emission. A detailed study of the scintillation of Ar-CF$_4$ mixtures at different concentrations has been performed to study the light emission of the gas in a triple GEM detector.

  6. Scintillation of liquid neon from electronic and nuclear recoils

    CERN Document Server

    Nikkel, J A; Lippincott, W H; McKinsey, D N

    2006-01-01

    We have measured the time dependence of scintillation light from electronic and nuclear recoils in liquid neon, finding a slow time constant of 15.4+-0.2 us. Pulse shape discrimination is investigated as a means of identifying event type in liquid neon. Finally, the nuclear recoil scintillation efficiency is measured to be 0.26+-0.03 for 387 keV nuclear recoils.

  7. Structural Origins of Scintillation: Metal Organic Frameworks as a Nanolaboratory

    Science.gov (United States)

    2016-06-01

    use. The results of this project provide fundamental insight into the electronic and structural features of novel scintillating materials known as...Energy/Work/Power electron volt (eV) 1.602 177 × 10 –19 joule (J) erg 1 × 10 –7 joule (J) kiloton (kt) (TNT equivalent) 4.184 × 10 12 joule (J...flexible structure, present unique advantages for radiation detection over existing organic scintillator materials . In addition, MOFs provide a

  8. Li-containing scintillating bolometers for low background physics

    Directory of Open Access Journals (Sweden)

    Pattavina L.

    2014-01-01

    Full Text Available We present the performances of Li-based compounds used as scintillating bolometer for rare decay studies such as double-beta decay and direct dark matter investigations. The compounds are tested in a dilution refrigerator installed in the underground laboratory of Laboratori Nazionali del Gran Sasso (Italy. Low temperature scintillating properties are investigated by means of different radioactive sources, and the radio-purity level for internal contaminations are estimated for possible employment for next generation experiments.

  9. Scintillation of thin tetraphenyl butadiene films under alpha particle excitation

    Energy Technology Data Exchange (ETDEWEB)

    Pollmann, Tina, E-mail: tina@owl.phy.queensu.c [Department of Physics, Engineering Physics, and Astronomy, Queens University, Kingston, Ontario, K7L 3N6 (Canada); Boulay, Mark; Kuzniak, Marcin [Department of Physics, Engineering Physics, and Astronomy, Queens University, Kingston, Ontario, K7L 3N6 (Canada)

    2011-04-11

    The alpha induced scintillation of the wavelength shifter 1,1,4,4-tetraphenyl-1,3-butadiene (TPB) was studied to improve the understanding of possible surface alpha backgrounds in the DEAP dark matter search experiment. We found that vacuum deposited thin TPB films emit 882{+-}210 photons per MeV under alpha particle excitation. The scintillation pulse shape consists of a double exponential decay with lifetimes of 11{+-}5 and 275{+-}10ns.

  10. Lanthanum halide nanoparticle scintillators for nuclear radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Guss, Paul; Guise, Ronald [Remote Sensing Laboratory, P.O. Box 98521, M/S RSL-48, Las Vegas, Nevada 89193 (United States); Yuan Ding [National Security Technologies, LLC, Los Alamos Operations, P.O. Box 809, M/S LAO/C320, Los Alamos, New Mexico 87544 (United States); Mukhopadhyay, Sanjoy [Remote Sensing Laboratory-Andrews, Building 1783, Arnold Avenue Andrews AFB, Maryland 20762 (United States); O' Brien, Robert; Lowe, Daniel [University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154 (United States); Kang Zhitao; Menkara, Hisham [Georgia Tech Research Institute, 925 Dalney St., Atlanta, Georgia 30332 (United States); Nagarkar, Vivek V. [RMD, Inc., 44 Hunt Street, Watertown, Massachusetts 02472 (United States)

    2013-02-14

    Nanoparticles with sizes <10 nm were fabricated and characterized for their nanocomposite radiation detector properties. This work investigated the properties of several nanostructured radiation scintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum trifluoride. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation.

  11. Performance studies of scintillating ceramic samples exposed to ionizing radiation

    CERN Document Server

    Dissertori, G; Nessi-Tedaldi, F; Wallny, R

    2014-01-01

    Scintillating ceramics are a promising, new development for various applications in science and industry. Their application in calorimetry for particle physics experiments is expected to involve an exposure to high levels of ionizing radiation. In this paper, changes in performance have been measured for scintillating ceramic samples of different composition after exposure to penetrating ionizing radiation up to a dose of 38 kGy. 2012 IEEE Nuclear Science Symposium Conference Record

  12. Performance studies of scintillating ceramic samples exposed to ionizing radiation

    CERN Document Server

    Dissertori, G; Nessi-Tedaldi, F; Pauss, F; Wallny, R

    2012-01-01

    Scintillating ceramics are a promising, new development for various applications in science and industry. Their application in calorimetry for particle physics experiments is expected to involve an exposure to high levels of ionizing radiation. In this paper, changes in performance have been measured for scintillating ceramic samples of different composition after exposure to penetrating ionizing radiation up to a dose of 38 kGy.

  13. High effective atomic number polymer scintillators for gamma ray spectroscopy

    Science.gov (United States)

    Cherepy, Nerine Jane; Sanner, Robert Dean; Payne, Stephen Anthony; Rupert, Benjamin Lee; Sturm, Benjamin Walter

    2014-04-15

    A scintillator material according to one embodiment includes a bismuth-loaded aromatic polymer having an energy resolution at 662 keV of less than about 10%. A scintillator material according to another embodiment includes a bismuth-loaded aromatic polymer having a fluor incorporated therewith and an energy resolution at 662 keV of less than about 10%. Additional systems and methods are also presented.

  14. Continuing Studies on Lead/Scintillating Fibres Calorimetry (LFC)

    CERN Multimedia

    2002-01-01

    Starting from the results obtained in the framework of the LAA Project~2B, we propose a continuation of the R&D on lead/scintillating fibres calorimetry (``spaghetti calorimetry''), including further tests on the old calorimeter prototypes and the construction and testing of new prototypes. The main results we pursue concern the performances of a projective calorimeter built with new, cheaper, techniques and the radiation hardness of the scintillating fibres, the optimization of a preshower detector system is also studied.

  15. Refractive Interstellar Scintillation for Flux Density Variations of Two Pulsars

    Institute of Scientific and Technical Information of China (English)

    周爱芝; 吴鑫基; 艾力·伊沙木丁

    2003-01-01

    The flux density structure functions of PSRs B0525+21 and B2111+46 are calculated with the refractive interstellar scintillation (RISS) theory. The theoretical curves are in good agreement with observations [Astrophys.J. 539 (2000) 300] (hereafter S2000). The spectra of the electron density fluctuations both are of Kolmogorov spectra. We suggest that the flux density variations observed for these two pulsars are attributed to refractive interstellar scintillation, not to intrinsic variability.

  16. Small field diode correction factors derived using an air core fibre optic scintillation dosimeter and EBT2 film.

    Science.gov (United States)

    Ralston, Anna; Liu, Paul; Warrener, Kirbie; McKenzie, David; Suchowerska, Natalka

    2012-05-07

    There is no commercially available real-time dosimeter that can accurately measure output factors for field sizes down to 4 mm without the use of correction factors. Silicon diode detectors are commonly used but are not dosimetrically water equivalent, resulting in energy dependence and fluence perturbation. In contrast, plastic scintillators are nearly dosimetrically water equivalent. A fibre optic dosimeter (FOD) with a 0.8 mm(3) plastic scintillator coupled to an air core light guide was used to measure the output factors for Novalis/BrainLab stereotactic cones of diameter 4-30 mm and Novalis MLC fields of width 5-100 mm. The FOD data matched the output factors measured by a 0.125 cm(3) Semiflex ion chamber for the MLC fields above 30 mm and those measured with the EBT2 radiochromic film for the cones and MLC fields below 30 mm. Relative detector readings were obtained with four diode types (IBA SFD, EFD, PFD, PTW 60012) for the same fields. Empirical diode correction factors were determined by taking the ratio of FOD output factors to diode relative detector readings. The diodes were found to over-respond by 3%-16% for the smallest field. There was good agreement between different diodes of the same model number.

  17. An instrument for measuring scintillators efficiently based on silicon photomultipliers

    Science.gov (United States)

    Yang, M. J.; Zhang, Z. M.; Wang, Y. J.; Li, D. W.; Zhou, W.; Tang, H. H.; Liu, Y. T.; Chai, P.; Shuai, L.; Huang, X. C.; Liu, S. Q.; Zhu, M. L.; Jiang, X. P.; Zhang, Y. W.; Li, T.; Ma, B.; Sun, S. F.; Sun, L. Y.; Wang, Q.; Lu, Z. R.; Zhang, T.; Wei, L.

    2016-11-01

    An instrument used for measuring multiple scintillators' light output and energy resolution was developed. The instrument consisted of a light sensor array which was composed of 64 discrete SiPMs (Silicon Photomultipliers), a corresponding individual channel readout electronics system, and a data processing algorithm. A Teflon grid and a large interval between adjacent SiPMs were employed to eliminate the optical cross talk among scintillators. The scintillators' light output was obtained by comparing with a reference sample with known light output. Given the SiPM temperature dependency and the difference among each SiPM, a temperature offset correction algorithm and a non-uniformity correction algorithm were added to the instrument. A positioning algorithm, based on nine points, was designed to evaluate the performance of a scintillator array. Tests were performed to evaluate the instrument's performance. The uniformity of 64 channels for light output measurement was better than 98%, the stability was better than 98% when temperature varied from 15 °C to 40 °C, and the nonlinearity under 511 keV was better than 2%. This instrument was capable of selecting scintillators and evaluating the packaging technology of scintillator arrays with high efficiency and accuracy.

  18. A multipurpose test stand for scintillator decay lifetimes

    Science.gov (United States)

    Mangan, Tymothy; P-23, Neutron Science; Technology Team

    2016-09-01

    We built a prototype test stand in order to measure novel scintillator materials' decay lifetimes. Radiography and imaging are valuable diagnostic tools for studying dynamic experiments, thus new scintillator materials are needed to improve the resolution of the current observational systems. A collaborative effort by the neutron imaging and x-ray radiography teams is underway to study the novel scintillator materials developed at LANL and by outside collaborators. Decay lifetimes are an important characteristic of a scintillator material and so by developing this prototype we have provided an avenue to further scintillator development. We confirmed the effectiveness of this prototype by comparing known scintillator decay lifetimes of LYSO and polystyrene samples. In our proof-of-concept prototype we use an 80 Gs/s oscilloscope. With future implementation of a fully developed test stand, we will use a digital data acquisition system to record complete waveforms to conduct a post-processing analysis of the decay times. Results of the prototype test and potential improvements to final test stand design will be presented. LA-UR-16-25229 Los Alamos National Lab, Physics Division.

  19. Stimulated scintillation emission depletion X-ray imaging.

    Science.gov (United States)

    Alekhin, M S; Patton, G; Dujardin, C; Douissard, P-A; Lebugle, M; Novotny, L; Stampanoni, M

    2017-01-23

    X-ray microtomography is a widely applied tool for noninvasive structure investigations. The related detectors are usually based on a scintillator screen for the fast in situ conversion of an X-ray image into an optical image. Spatial resolution of the latter is fundamentally diffraction limited. In this work, we introduce stimulated scintillation emission depletion (SSED) X-ray imaging where, similar to stimulated emission depletion (STED) microscopy, a depletion beam is applied to the scintillator screen to overcome the diffraction limit. The requirements for the X-ray source, the X-ray flux, the scintillator screen, and the STED beam were evaluated. Fundamental spatial resolution limits due to the spread of absorbed X-ray energy were estimated with Monte Carlo simulations. The SSED proof-of-concept experiments demonstrated 1) depletion of X-ray excited scintillation, 2) partial confinement of scintillating regions to sub-diffraction sized volumes, and 3) improvement of the imaging contrast by applying SSED.

  20. Phenotypic plasticity's impacts on diversification and speciation.

    Science.gov (United States)

    Pfennig, David W; Wund, Matthew A; Snell-Rood, Emilie C; Cruickshank, Tami; Schlichting, Carl D; Moczek, Armin P

    2010-08-01

    Phenotypic plasticity (the ability of a single genotype to produce multiple phenotypes in response to variation in the environment) is commonplace. Yet its evolutionary significance remains controversial, especially in regard to whether and how it impacts diversification and speciation. Here, we review recent theory on how plasticity promotes: (i) the origin of novel phenotypes, (ii) divergence among populations and species, (iii) the formation of new species and (iv) adaptive radiation. We also discuss the latest empirical support for each of these evolutionary pathways to diversification and identify potentially profitable areas for future research. Generally, phenotypic plasticity can play a largely underappreciated role in driving diversification and speciation.