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Sample records for radiation hard scintillation

  1. Development of radiation hard scintillators

    NASA Astrophysics Data System (ADS)

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

    1993-01-01

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

  2. Development of radiation hard scintillators

    SciTech Connect

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

    1992-05-01

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

  3. Development of radiation hard scintillators

    NASA Astrophysics Data System (ADS)

    Markley, F.; Davidson, M.; Keller, J.; Foster, G.; Pla-Dalmau, A.; Harmon, J.; Biagtan, E.; Schueneman, G.; Senchishin, V.; Gustfason, H.

    1993-11-01

    The authors have demonstrated that the radiation stability of scintillators made from styrene polymer is very much improved by compounding with pentaphenyl trimethyl trisiloxane (DC 705 vacuum pump oil). The resulting scintillators are softer than desired, so they decided to make the scintillators directly from monomer where the base resin could be easily crosslinked to improve the mechanical properties. They can now demonstrate that scintillators made directly from the monomer, using both styrene and 4-methyl styrene, are also much more radiation resistant when modified with DC705 oil. In fact, they retain from 92% to 95% of their original light output after gamma irradiation to 10 Mrads in nitrogen with air annealing. When these scintillators made directly from monomer are compared with scintillators of the same composition made from polymer the latter have much higher light outputs. They commonly reach 83% while those made from monomer give only 50% to 60% relative to the reference, BC408. When oil modified scintillators using both p-terphenyl and tetra phenyl butadiene are compared with identical scintillators except that they use 3 hydroxy-flavone as the only luminophore the radiation stability is the same. However the 3HF system gives only 30% as much light as BC408 instead of 83% when both are measured with a green extended Phillips XP2081B phototube.

  4. Development of radiation hard scintillators

    SciTech Connect

    Markley, F.; Davidson, M.; Keller, J.; Foster, G.; Pla-Dalmau, A.; Harmon, J.; Biagtan, E.; Schueneman, G.; Senchishin, V.; Gustfason, H.; Rivard, M.

    1993-11-01

    The authors have demonstrated that the radiation stability of scintillators made from styrene polymer is very much improved by compounding with pentaphenyltrimethyltrisiloxane (DC 705 vacuum pump oil). The resulting scintillators are softer than desired, so they decided to make the scintillators directly from monomer where the base resin could be easily crosslinked to improve the mechanical properties. They can now demonstrate that scintillators made directly from the monomer, using both styrene and 4-methyl styrene, are also much more radiation resistant when modified with DC705 oil. In fact, they retain from 92% to 95% of their original light output after gamma irradiation to 10 Mrads in nitrogen with air annealing. When these scintillators made directly from monomer are compared with scintillators of the same composition made from polymer the latter have much higher light outputs. They commonly reach 83% while those made form monomer give only 50% to 60% relative to the reference, BC408. When oil modified scintillators using both p-terphenyl and tetraphenylbutadiene are compared with identical scintillators except that they use 3 hydroxy-flavone as the only luminophore the radiation stability is the same. However the 3HF system gives only 30% as much light as BC408 instead of 83% when both are measured with a green extended Phillips XP2081B phototube.

  5. Scintillation Detectors for Radiation-Hard Electromagnetic Calorimeters

    NASA Astrophysics Data System (ADS)

    Löhner, H.

    2005-02-01

    For the application in the compact and radiation hard electromagnetic (EM) calorimeter in the PANDA detection system at the new GSI facility, we have started to advance scintillation crystals and the light detection technique. PANDA is the universal internal-target detection system for charmonium spectroscopy and the search for glue-balls and hybrid states in antiproton annihilations. In particular, the large dynamic range from several GeV down to a detection threshold of some MeV for EM radiation and the expected high background rate of neutrons and ions will impose severe requirements on crystals and light sensors. In the magnetic environment of tracking devices the use of Avalanche Photodiodes (APD's) is preferred. In order to achieve suitable resolution for low energy hadrons and photons, the light output of crystals will have to be improved by special production techniques, activation and doping. These procedures might have implications for the radiation hardness. We report on measurements of signal response and radiation damage in crystals of PbWO4 and BGO both from the BTCP (Russia) and SICCAS (China) production sites. Beams of protons, electrons and photons have been applied while detectors with either phototube or APD readout were operated in the range from room temperature to -20°C. Results on light yield and energy resolution are presented. We report on the reduction of light transmission after proton irradiation and results from electron-spin resonance studies on irradiated crystals to analyse the cause of radiation damage.

  6. Radiation Hard Plastic Scintillators for a New Generation of Particle Detectors

    NASA Astrophysics Data System (ADS)

    Dettmann, M.; Herrig, V.; Maldonis, J.; Neuhaus, J.; Shrestha, D.; Rajbhandari, P.; Thune, Z.; Been, M.; Martinez-Szewczyk, M.; Khristenko, V.; Onel, Y.; Akgun, U.

    2017-03-01

    The radiation hardness of specific scintillating materials used in particle physics experiments is one of the main focuses of research in detector development. This report summarizes the preparation methods, light yield characterization and radiation damage tests of a plastic scintillator with a polysiloxane base and pTP and bis-MSB dopants. The scintillator is shown to be a promising candidate for particle detectors with its intense light output around 400 nm and very little scintillation or transmission loss after proton irradiation of 4 × 105 Gy.

  7. R&D of Radiation-Hard Scintillators and WLS Fibers

    NASA Astrophysics Data System (ADS)

    Tiras, Emrah; Wetzel, James; Bilki, Burak; Durgut, Suleyman; Onel, Yasar; Winn, David

    2017-01-01

    Radiation resistant and high light-yield scintillators are in more need than ever at particle physics experiments. In this regard, several polyethylene-based and quartz-based scintillating materials and WLS fibers have been studied. Radiation resistance of plastic scintillators such as PEN, PET, SiX and Eljen samples and WLS fibers has been studied over time after they are exposed to 1.4 and 14 MRad total radiation by 137Cs gamma source. The light-yield and timing measurements of the plastic scintillators as well as coated quartz plates have been studied in beam test at Fermilab Test Beam Facility (FTBF). Here, we discuss the recent developments and the results of beam tests and laboratory measurements.

  8. Radiation Hardness Tests of a Scintillation Detector with Wavelength Shifting Fiber Readout

    SciTech Connect

    Alfaro, R.; Sandoval, A.; Cruz, E.; Martinez, M. I.; Paic, G.; Montano, L. M.

    2006-09-25

    We have performed radiation tolerance tests on the BCF-99-29MC wavelength shifting fibers and the BC404 plastic scintillator from Bicron as well as on silicon rubber optical couplers. We used the 60Co gamma source at the Instituto de Ciencias Nucleares facility to irradiate 30-cm fiber samples with doses from 50 Krad to 1 Mrad. We also irradiated a 10x10 cm2 scintillator detector with the WLS fibers embedded on it with a 200 krad dose and the optical conectors between the scintillator and the PMT with doses from 100 to 300 krad. We measured the radiation damage on the materials by comparing the pre- and post-irradiation optical transparency as a function of time.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  11. Scintillator Waveguide For Sensing Radiation

    DOEpatents

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

    2003-04-22

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  13. Interstellar scintillations of pulsar radiation.

    PubMed

    Lang, K R

    1969-12-12

    Time fluctuations in the intensity of pulsed radiation from CP 0834, CP 1133, AP 1237, and CP 1919 have been investigated. Power spectra, modulation indices, frequency distributions, and decorrelation frequencies are consistent with scintillation theory. If it is assumed that these scintillations are due to irregularities in the interstellar medium that travel at a velocity of 20 kilometers per second, the irregularities have a scale size on the order of 10(4) kilometers and a distance from the earth of approximately 70 parsecs. These interstellar scintillations would not have been observed if the apparent angular diameters of the pulsars were larger than 0.3 X 10(-5) second of arc, and they would cause even a point radio source to have an apparent angular diameter of approximately 10(-3) second of arc at 318 megahertz.

  14. Composite scintillators for detection of ionizing radiation

    DOEpatents

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

    2010-12-28

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

  15. Radiation from hard objects

    SciTech Connect

    Canavan, G.H.

    1997-02-01

    The inference of the diameter of hard objects is insensitive to radiation efficiency. Deductions of radiation efficiency from observations are very sensitive - possibly overly so. Inferences of the initial velocity and trajectory vary similarly, and hence are comparably sensitive.

  16. Waveshifters and Scintillators for Ionizing Radiation Detection

    SciTech Connect

    B.Baumgaugh; J.Bishop; D.Karmgard; J.Marchant; M.McKenna; R.Ruchti; M.Vigneault; L.Hernandez; C.Hurlbut

    2007-12-11

    Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments.

  17. PLASTIC SCINTILLATOR FOR RADIATION DOSIMETRY.

    PubMed

    Kim, Yewon; Yoo, Hyunjun; Kim, Chankyu; Lim, Kyung Taek; Moon, Myungkook; Kim, Jongyul; Cho, Gyuseong

    2016-09-01

    Inorganic scintillators, composed of high-atomic-number materials such as the CsI(Tl) scintillator, are commonly used in commercially available a silicon diode and a scintillator embedded indirect-type electronic personal dosimeters because the light yield of the inorganic scintillator is higher than that of an organic scintillator. However, when it comes to tissue-equivalent dose measurements, a plastic scintillator such as polyvinyl toluene (PVT) is a more appropriate material than an inorganic scintillator because of the mass energy absorption coefficient. To verify the difference in the absorbed doses for each scintillator, absorbed doses from the energy spectrum and the calculated absorbed dose were compared. From the results, the absorbed dose of the plastic scintillator was almost the same as that of the tissue for the overall photon energy. However, in the case of CsI, it was similar to that of the tissue only for a photon energy from 500 to 4000 keV. Thus, the values and tendency of the mass energy absorption coefficient of the PVT are much more similar to those of human tissue than those of the CsI. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Effects of radiation on scintillating fiber performance

    SciTech Connect

    Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E.; Young, K.G.; Carey, R.; Rothman, M.; Sulak, L.; Worstell, W.; Parr, H.

    1992-12-31

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain needed information and calculational procedures used in performing predications for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. These calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented.

  19. Effects of radiation on scintillating fiber performance

    SciTech Connect

    Young, K.G.; Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E. ); Carey, R.; Rothman, M.; Sulak, L.; Worstell, W. ); Paar, H. )

    1993-08-01

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain desired information and calculational procedures used in performing predictions for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. The calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented.

  20. New radiation stable and long-lived plastic scintillator for the SSC

    SciTech Connect

    Senchishin, V.; Koba, V.; Korneeva, O.

    1993-11-01

    The study of the influence of the concentration of secondary flour, high concentrations of primary dopant, diffusion enhancer, and stabilizer, on radiation hardness is presented. It is concluded that the diffusion enhancing technique is the most powerful method for improving rad hardness. A new polystyrene scintillator which contains 2% pT and 0.02% POPOP and 20% diffusion enhancer and 0.02% stabilizer gave 91% of initial light output immediately after 3MRad in air. Data are presented that show that scintillator prepared form commercial polymer is more radiation hard and has greater light output than scintillator prepared from monomer. It is assumed that this difference is due to different molecular weight distributions. Some protocols for acceleration of aging (yellowing and crazing) are presented. It is shown that one of the main reasons for aging of plastic scintillators is residual monomer.

  1. Plastic scintillators modifications for a selective radiation detection

    SciTech Connect

    Hamel, Matthieu; Bertrand, Guillaume H.V.; Carrel, Frederick; Coulon, Romain; Dumazert, Jonathan; Montbarbon, Eva; Sguerra, Fabien

    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)

  2. SSPM scintillator readout for gamma radiation detection

    NASA Astrophysics Data System (ADS)

    Baker, Stuart A.; Stapels, Christopher; Green, J. Andrew; Guise, Ronald E.; Young, Jason A.; Franks, Larry; Stokes, Britany; Wendelberger, Elizabeth

    2011-09-01

    Silicon-based photodetectors offer several benefits relative to photomultiplier tube-based scintillator systems. Solid-state photomultipliers (SSPM) can realize the gain of a photomultiplier tube (PMT) with the quantum efficiency of silicon. The advantages of the solid-state approach must be balanced with adverse trade-offs, for example from increased dark current, to optimize radiation detection sensitivity. We are designing a custom SSPM that will be optimized for green emission of thallium-doped cesium iodide (CsI(Tl)). A typical field gamma radiation detector incorporates thallium doped sodium iodide (NaI(Tl)) and a radiation converter with a PMT. A PMT's sensitivity peaks in the blue wavelengths and is well matched to NaI(Tl). This paper presents results of photomultiplier sensitivity relative to conventional SSPMs and discusses model design improvements. Prototype fabrications are in progress.

  3. SSPM Scintillator Readout for Gamma Radiation Detection

    SciTech Connect

    Baker, S A; Wendelberger, B; Young, J A; Green, J A; Guise, R E; Franks, L; Staples, C

    2011-09-01

    Silicon-based photodetectors offer several benefits relative to photomultiplier tube–based scintillator systems. Solid-state photomultipliers (SSPM) can realize the gain of a photomultiplier tube (PMT) with the quantum efficiency of silicon. The advantages of the solid-state approach must be balanced with adverse trade-offs, for example from increased dark current, to optimize radiation detection sensitivity. We are designing a custom SSPM that will be optimized for green emission of thallium-doped cesium iodide (CsI(Tl)). A typical field gamma radiation detector incorporates thallium doped sodium iodide (NaI(Tl)) and a radiation converter with a PMT. A PMT’s sensitivity peaks in the blue wavelengths and is well matched to NaI(Tl). This paper presents results of photomultiplier sensitivity relative to conventional SSPMs and discusses model design improvements. Prototype fabrications are in progress.

  4. Report on radiation exposure of lead-scintillator stack

    SciTech Connect

    Underwood, D.G.

    1990-11-08

    A stack of lead and scintillator was placed in a neutral beam obtained from targeting 800 GeV protons. Small pieces of film containing radiochromic dye were placed adjacent to the layers of scintillator for the purpose of measuring the radiation dose to the scintillator. Our motivation was to calibrate the radiation dose obtainable in this manner for future tests of scintillator for SSC experiments and to relate dose to flux to check absolute normalization for calculations. We also observed several other radiation effects which should be considered for both damage and compensation in a calorimeter.

  5. Measurement of radiation damage of water-based liquid scintillator and liquid scintillator

    DOE PAGES

    Bignell, L. J.; Diwan, M. V.; Hans, S.; ...

    2015-10-19

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of 5% scintillating phase) exhibit light yield reductions of 1.74 ± 0.55 % andmore » 1.31 ± 0.59 % after ≈ 800 Gy of proton dose, respectively. Some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical context, a scintillating phantom used for proton therapy treatment plan verification would exhibit a systematic light yield reduction of approximately 0.1% after a year of operation.« less

  6. Measurement of radiation damage of water-based liquid scintillator and liquid scintillator

    SciTech Connect

    Bignell, L. J.; Diwan, M. V.; Hans, S.; Jaffe, D. E.; Rosero, R.; Vigdor, S.; Viren, B.; Worcester, E.; Yeh, M.; Zhang, C.

    2015-10-19

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of 5% scintillating phase) exhibit light yield reductions of 1.74 ± 0.55 % and 1.31 ± 0.59 % after ≈ 800 Gy of proton dose, respectively. Some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical context, a scintillating phantom used for proton therapy treatment plan verification would exhibit a systematic light yield reduction of approximately 0.1% after a year of operation.

  7. Energy Transfer Based Nanocomposite Scintillator for Radiation Detection

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  8. Thermopile detector radiation hard readout

    NASA Astrophysics Data System (ADS)

    Gaalema, Stephen; Van Duyne, Stephen; Gates, James L.; Foote, Marc C.

    2010-08-01

    The NASA Jupiter Europa Orbiter (JEO) conceptual payload contains a thermal instrument with six different spectral bands ranging from 8μm to 100μm. The thermal instrument is based on multiple linear arrays of thermopile detectors that are intrinsically radiation hard; however, the thermopile CMOS readout needs to be hardened to tolerate the radiation sources of the JEO mission. Black Forest Engineering is developing a thermopile readout to tolerate the JEO mission radiation sources. The thermal instrument and ROIC process/design techniques are described to meet the JEO mission requirements.

  9. Radiation hard electronics for LHC

    NASA Astrophysics Data System (ADS)

    Raymond, M.; Millmore, M.; Hall, G.; Sachdeva, R.; French, M.; Nygård, E.; Yoshioka, K.

    1995-02-01

    A CMOS front end electronics chain is being developed by the RD20 collaboration for microstrip detector readout at LHC. It is based on a preamplifier and CR-RC filter, analogue pipeline and an analogue signal processor. Amplifiers and transistor test structures have been constructed and evaluated in detail using a Harris 1.2 μm radiation hardened CMOS process. Progress with larger scale elements, including 32 channel front end chips, is described. A radiation hard 128 channel chip, with a 40 MHz analogue multiplexer, is to be submitted for fabrication in July 1994 which will form the basis of the readout of the tracking system of the CMS experiment.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  11. Improved Growth Methods for LaBr3 Scintillation Radiation Detectors

    SciTech Connect

    McGregor, Douglas S

    2011-05-01

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

  12. Radiation effects in intrinsic 3HF scintillator

    NASA Astrophysics Data System (ADS)

    Bross, Alan D.; Pla-Dalmau, Anna

    1993-04-01

    Test scintillators of the type 3-hydroxyflavone (3HF) plus polystyrene were prepared with 3HF doping concentrations between 0.05% and 2.0% by weight. Ternary scintillators of the type p-terphenyl(1%)+3HF(0.01%) and p-terphenyl(1%)+3HF(0.1%) in polystyrene were also prepared. The scintillation light yield is given for all samples. Representative fluorescence and transmittance spectra are also shown. Changes in light yield, transmittance, and fluorescence are shown for 60Co irradiations with integrated doses of 10 and 30 Mrad.

  13. Synthesis and characterization of nanocomposite scintillators for radiation detection

    NASA Astrophysics Data System (ADS)

    Sahi, Sunil Kumar

    Inorganic single crystal and organic (plastic and liquid) scintillators are commonly used for radiation detection. Inorganic single crystals are efficient and have better energy resolution compared to organic scintillators. However, inorganic single crystals are difficult to grow in large size and hence expensive. On the other hand, fast decay time and ease of fabrication makes organic scintillators attractive for many applications. However, poor energy resolution of organic scintillators limits its applications in gamma ray spectroscopy. The poor energy resolution is due to the low Z-value and low density of organic scintillator. The Z-value of organic plastic scintillator can be increase by loading nanoparticles in plastic matrix. It is expected that the increase in Z-value would result in improve energy resolution of nanocomposite scintillator. However, the loss of optical transparency due to nanoparticles loading is one of the major concerns of nanocomposite scintillators. In this dissertation, we used different methods to synthesize La xCe1-xF3 nanoparticles with high dispersion in polymer matrix. High nanoparticle dispersion is important to load high concentration of nanoparticles into polymer matrix without losing the transparency of the polymer matrix. The as synthesized nanoparticles are dispersed into monomers and polymerized using heat initiated bulk polymerization method. Nanoparticles are characterized using TEM, XRD, FTIR and TGA. The optical and scintillation properties of nanoparticles and nanocomposites are studied using spectroscopic techniques. The pulse height spectra obtained using nanocomposite fabricated by loading up to 30 wt% nanoparticles clearly show a photopeak for the 122 keV line of the Co-57 isotope. The generation of the photopeak is due to the enhanced photoelectric effect as a result of increased effective atomic number (Zeff) and density of nanocomposite scintillator. The pulse height spectra of Cs-137 gamma source show a full

  14. Radiation Hardness Assurance (RHA) Guideline

    NASA Technical Reports Server (NTRS)

    Campola, Michael J.

    2016-01-01

    Radiation Hardness Assurance (RHA) consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the mission space environment. The subset of interests for NEPP and the REAG, are EEE parts. It is important to register that all of these undertakings are in a feedback loop and require constant iteration and updating throughout the mission life. More detail can be found in the reference materials on applicable test data for usage on parts.

  15. Effects of radiation on scintillating fiber performance. [SSC hadron calorimeter

    SciTech Connect

    Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E.; Young, K.G. ); Carey, R.; Rothman, M.; Sulak, L.; Worstell, W. ); Parr, H. )

    1992-01-01

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain needed information and calculational procedures used in performing predications for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. These calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented.

  16. Study of radiation hardness of pure CsI crystals for Belle-II calorimeter

    NASA Astrophysics Data System (ADS)

    Boyarintsev, A.; Boyarintseva, Y.; Gektin, A.; Shiran, N.; Shlyakhturov, V.; Taranyuk, V.; Timoshenko, N.; Bobrov, A.; Garmash, A.; Golkovski, M.; Kuzmin, A.; Matvienko, D.; Savrovski, P.; Shebalin, V.; Shwartz, B.; Vinokurova, A.; Vorobyev, V.; Zhilich, V.; Krumshtein, Z. V.; Nozdrin, A. A.; Olshevsky, A. G.

    2016-03-01

    A study of the radiation hardness of pure CsI crystals 30 cm long was performed with a uniformly absorbed dose of up to 14.3 krad. This study was initiated by the proposed upgrade of the end cap calorimeter of the Belle-II detector, using pure CsI crystals. A set of 14 crystals of truncated pyramid shape used in this study was produced at the Institute for Scintillation Materials NAS from 14 different ingots grown with variations of the growing technology. Interrelationship of crystal scintillation characteristics, radiation hardness and the growing technology was observed.

  17. Automated radiation hard ASIC design tool

    NASA Technical Reports Server (NTRS)

    White, Mike; Bartholet, Bill; Baze, Mark

    1993-01-01

    A commercial based, foundry independent, compiler design tool (ChipCrafter) with custom radiation hardened library cells is described. A unique analysis approach allows low hardness risk for Application Specific IC's (ASIC's). Accomplishments, radiation test results, and applications are described.

  18. Extractive-scintillating resin produced by radiation polymerization

    NASA Astrophysics Data System (ADS)

    Vincze, Á.; Solymosi, J.; Kása, I.; Sáfrány, Á.

    2007-08-01

    The characterization of a resin material is presented, which contains selective complexing and scintillating molecules in chemically bound form. The resin material is produced via radiation polymerization of the solution of 2-(4-allyloxy-phenyl)-5-phenyl oxazole, 5-(allyloxy-phenyl)-2-[4-(5-phenyl-oxazole-2-il)-phenyl] oxazole, diethylene glycol dimethacrylate (DEGMA), styrene and the allyl derivative of a 18C6 crown ether-dicarbolic acid complexing agent. The product is a macroporous polymer matrix, which shows both excellent scintillation properties and ion binding capacity for radioanalytical purposes.

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

    SciTech Connect

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

    2013-07-15

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

  20. Bulk semiconducting scintillator device for radiation detection

    DOEpatents

    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.

  1. The hard X-ray response of Ce-doped lanthanum halide scintillators

    NASA Astrophysics Data System (ADS)

    Owens, Alan; Bos, A. J. J.; Brandenburg, S.; Dorenbos, P.; Drozdowski, W.; Ostendorf, R. W.; Quarati, F.; Webb, A.; Welter, E.

    2007-04-01

    We summarize the results of a number of hard X-ray measurements on cerium-doped LaCl 3 and LaBr 3 scintillators. The experiment was carried out at the HASYLAB synchrotron radiation facility using highly monochromatic pencil beams across the energy range 10.5-100 keV. Additional full-area measurements were carried out using radioactive sources. All measurements were carried out at room temperature. The measured FWHM energy resolutions (Δ E/ E) under pencil beam illumination were 29% (LaBr 3) and 32.4% (LaCl 3) at 10.5 keV falling to 7.8% (LaBr 3) and 9.2% (LaCl 3) at 100 keV. At 662 keV, the energy resolutions were 3.9% and 3.0% FWHM. The proportionality of the energy responses shows marked deviations from linearity above and below the La edge at 39.8 keV. At the edge the energy response changes by 3%. Fine structure across the edge was also investigated using single photon count rate measurements taken in 1 eV steps across the edge. The data show considerable near-edge structure when compared to curves generated from standard atomic data tables. However, very little evidence was found for extended X-ray fine structure suggesting that the bulk of the structure arises from the local coordination environment.

  2. Organic Scintillation Detectors for Spectroscopic Radiation Portal Monitors

    NASA Astrophysics Data System (ADS)

    Paff, Marc Gerrit

    Thousands of radiation portal monitors have been deployed worldwide to detect and deter the smuggling of nuclear and radiological materials that could be used in nefarious acts. Radiation portal monitors are often installed at bottlenecks where large amounts of people or goods must traverse. Examples of use include scanning cargo containers at shipping ports, vehicles at border crossings, and people at high profile functions and events. Traditional radiation portal monitors contain separate detectors for passively measuring neutron and gamma ray count rates. 3He tubes embedded in polyethylene and slabs of plastic scintillators are the most common detector materials used in radiation portal monitors. The radiation portal monitor alarm mechanism relies on measuring radiation count rates above user defined alarm thresholds. These alarm thresholds are set above natural background count rates. Minimizing false alarms caused by natural background and maximizing sensitivity to weakly emitting threat sources must be balanced when setting these alarm thresholds. Current radiation portal monitor designs suffer from frequent nuisance radiation alarms. These radiation nuisance alarms are most frequently caused by shipments of large quantities of naturally occurring radioactive material containing cargo, like kitty litter, as well as by humans who have recently undergone a nuclear medicine procedure, particularly 99mTc treatments. Current radiation portal monitors typically lack spectroscopic capabilities, so nuisance alarms must be screened out in time-intensive secondary inspections with handheld radiation detectors. Radiation portal monitors using organic liquid scintillation detectors were designed, built, and tested. A number of algorithms were developed to perform on-the-fly radionuclide identification of single and combination radiation sources moving past the portal monitor at speeds up to 2.2 m/s. The portal monitor designs were tested extensively with a variety of

  3. Ionization and proton induced radiation damage in crystal scintillators (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhu, Ren-Yuan

    2016-09-01

    Crystal detectors have been used widely in high energy and nuclear physics experiments, medical instruments and homeland security applications. A crucial issue for crystal detectors to be used for future HEP experiments at the energy and intensity frontiers is radiation damage by ionization dose as well as charged and neutral hadrons. This paper reports recent investigations on radiation damage in various crystal scintillators. Irradiations up to 340 Mrad of ionization dose, 1E16 p/cm^2 fluence and 1016 n/cm2 fluence were carried out at the JPL total ionization dose facility and the Los Alamos Neutron Science Center, respectively. Results of these investigations show excellent radiation hardness of bright and fast LYSO crystals which may provide a stable detector in an extreme harsh radiation environment, such as the proposed HL-LHC.

  4. Water-equivalent fiber radiation dosimeter with two scintillating materials

    PubMed Central

    Qin, Zhuang; Hu, Yaosheng; Ma, Yu; Lin, Wei; Luo, Xianping; Zhao, Wenhui; Sun, Weimin; Zhang, Daxin; Chen, Ziyin; Wang, Boran; Lewis, Elfed

    2016-01-01

    An inorganic scintillating material plastic optical fiber (POF) dosimeter for measuring ionizing radiation during radiotherapy applications is reported. It is necessary that an ideal dosimeter exhibits many desirable qualities, including water equivalence, energy independence, reproducibility, dose linearity. There has been much recent research concerning inorganic dosimeters. However, little reference has been made to date of the depth-dose characteristics of dosimeter materials. In the case of inorganic scintillating materials, they are predominantly non water-equivalent, with their effective atomic weight (Zeff) being typically much greater than that of water. This has been a barrier in preventing inorganic scintillating material dosimeter from being used in actual clinical applications. In this paper, we propose a parallel-paired fiber light guide structure to solve this problem. Two different inorganic scintillating materials are embedded separately in the parallel-paired fiber. It is shown that the information of water depth and absorbed dose at the point of measurement can be extracted by utilizing their different depth-dose properties. PMID:28018715

  5. Water-equivalent fiber radiation dosimeter with two scintillating materials.

    PubMed

    Qin, Zhuang; Hu, Yaosheng; Ma, Yu; Lin, Wei; Luo, Xianping; Zhao, Wenhui; Sun, Weimin; Zhang, Daxin; Chen, Ziyin; Wang, Boran; Lewis, Elfed

    2016-12-01

    An inorganic scintillating material plastic optical fiber (POF) dosimeter for measuring ionizing radiation during radiotherapy applications is reported. It is necessary that an ideal dosimeter exhibits many desirable qualities, including water equivalence, energy independence, reproducibility, dose linearity. There has been much recent research concerning inorganic dosimeters. However, little reference has been made to date of the depth-dose characteristics of dosimeter materials. In the case of inorganic scintillating materials, they are predominantly non water-equivalent, with their effective atomic weight (Zeff) being typically much greater than that of water. This has been a barrier in preventing inorganic scintillating material dosimeter from being used in actual clinical applications. In this paper, we propose a parallel-paired fiber light guide structure to solve this problem. Two different inorganic scintillating materials are embedded separately in the parallel-paired fiber. It is shown that the information of water depth and absorbed dose at the point of measurement can be extracted by utilizing their different depth-dose properties.

  6. Radiation-Hardness Data For Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Nichols, D. K.; Brown, S. F.; Gauthier, M. K.; Martin, K. E.

    1984-01-01

    Document presents data on and analysis of radiation hardness of various semiconductor devices. Data specifies total-dose radiation tolerance of devices. Volume 1 of report covers diodes, bipolar transistors, field effect transistors, silicon controlled rectifiers and optical devices. Volume 2 covers integrated circuits. Volume 3 provides detailed analysis of data in volumes 1 and 2.

  7. Radiation-Hardness Data For Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Nichols, D. K.; Brown, S. F.; Gauthier, M. K.; Martin, K. E.

    1984-01-01

    Document presents data on and analysis of radiation hardness of various semiconductor devices. Data specifies total-dose radiation tolerance of devices. Volume 1 of report covers diodes, bipolar transistors, field effect transistors, silicon controlled rectifiers and optical devices. Volume 2 covers integrated circuits. Volume 3 provides detailed analysis of data in volumes 1 and 2.

  8. Radiation-hard static induction transistor

    NASA Astrophysics Data System (ADS)

    Hanes, M. H.; Bartko, J.; Hwang, J.-M.; Rai-Choudhury, P.; Leslie, S. G.

    1988-12-01

    The design, fabriction, and characteristics of a 350-V, 100-A buried-gate static induction transistor (SIT) as a power switching device for applications to military and space environments (because of its potential for radiation hardness, high-frequency operation, and the incorporation of on-chip smart power sensor and logic functions) are described. The potential radiation hardness of this class of devices was evaluated by measurement of SIT characteristics after irradiation with 100-Mrad (2-MeV) electrons and up to 10 to the 16th fission neutrons/sq cm. High-temperature operation and the possibility of radiation-damage self-annealing are discussed.

  9. Gas scintillation drift chambers with wave shifter read-out for hard X-ray astronomy

    NASA Technical Reports Server (NTRS)

    Sadoulet, Bernard; Lin, Robert P.; Weiss, Steven C.

    1987-01-01

    A major improvement in hard X-ray and gamma ray astrophysics could be provided by high pressure xenon time projection chambers where gas scintillation is used both for the measurement of the time of interaction and for the detection of the extracted electrons. This allows three dimensional imaging of naturally complex events (photoelectric interaction with escape photon, Compton scatter, and pair production). A novel read-out system based on wave shifter fibers, which is well suited to the high pressures and large areas required of a hard X-ray telescope is proposed. Expected performances are computed, potential problems are outlined, and the experimental effort to solve these problems are described.

  10. Radiation damage study of thin YAG:Ce scintillator using low-energy protons

    NASA Astrophysics Data System (ADS)

    Novotný, P.; Linhart, V.

    2017-07-01

    Radiation hardness of a 50 μ m thin YAG:Ce scintillator in a form of dependence of a signal efficiency on 3.1 MeV proton fluence was measured and analysed using X-ray beam. The signal efficiency is a ratio of signals given by a CCD chip after and before radiation damage. The CCD chip was placed outside the primary beam because of its protection from damage which could be caused by radiation. Using simplified assumptions, the 3.1 MeV proton fluences were recalculated to: ṡ 150 MeV proton fluences with intention to estimate radiation damage of this sample under conditions at proton therapy centres during medical treatment, ṡ 150 MeV proton doses with intention to give a chance to compare radiation hardness of the studied sample with radiation hardness of other detectors used in medical physics, ṡ 1 MeV neutron equivalent fluences with intention to compare radiation hardness of the studied sample with properties of position sensitive silicon and diamond detectors used in nuclear and particle physics. The following results of our research were obtained. The signal efficiency of the studied sample varies slightly (± 3%) up to 3.1 MeV proton fluence of c. (4 - 8) × 1014 cm-2. This limit is equivalent to 150 MeV proton fluence of (5 - 9) × 1016 cm-2, 150 MeV proton dose of (350 - 600) kGy and 1 MeV neutron fluence of (1 - 2) × 1016 cm-2. Beyond the limit, the signal efficiency goes gradually down. Fifty percent decrease in the signal efficiency is reached around 3.1 MeV fluence of (1 - 2) × 1016 cm-2 which is equivalent to 150 MeV proton fluence of around 2 × 1018 cm-2, 150 MeV proton dose of around 15 MGy and 1 MeV neutron equivalent fluence of (4 - 8) × 1017 cm-2. In contrast with position sensitive silicon and diamond radiation detectors, the studied sample has at least two order of magnitude greater radiation resistance. Therefore, YAG:Ce scintillator is a suitable material for monitoring of primary beams of particles of ionizing radiation.

  11. Ultra-fast LuI{sub 3}:Ce scintillators for hard x-ray imaging

    SciTech Connect

    Marton, Zsolt Miller, Stuart R.; Ovechkina, Elena; Singh, Bipin; Nagarkar, Vivek V.; Kenesei, Peter; Moore, Matthew D.; Woods, Russell; Almer, Jonathan D.; Miceli, Antonino

    2016-07-27

    We have developed ultra-fast cerium-coped lutetium-iodide (LuI{sub 3}:Ce) films thermally evaporated as polycrystalline, structured scintillator using hot wall epitaxy (HWE) method. The films have shown a 13 ns decay compared to the 28 ns reported for crystals. The fast speed coupled with its high density (∼5.6 g/cm{sup 3}), high effective atomic number (59.7), and the fact that it can be vapor deposited in a columnar form makes LuI{sub 3}:Ce an attractive candidate for high frame rate, high-resolution, hard X-ray imaging. In crystal form, LuI{sub 3}:Ce has demonstrated bright (>100,000 photons/MeV) green (540 nm) emission, which is well matched to commercial CCD/CMOS sensors and is critical for maintaining high signal to noise ratio in light starved applications. Here, we report on the scintillation properties of films and those for corresponding crystalline material. The vapor grown films were integrated into a high-speed CMOS imager to demonstrate high-speed radiography capability. The films were also tested at Advanced Photon Source, Argonne National Laboratory beamline 1-ID under hard X-ray irradiation. The data show a factor of four higher efficiency than the reference LuAG:Ce scintillators, high image quality, and linearity of scintillation response over a wide energy range. The films were employed to perform hard X-ray microtomography, the results of which will also be discussed.

  12. Polysiloxane scintillator composition

    DOEpatents

    Walker, James K.

    1992-01-01

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

  13. Polysiloxane scintillator composition

    DOEpatents

    Walker, J.K.

    1992-05-05

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

  14. Radiation Hardness Assurance for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Day, John H. (Technical Monitor)

    2002-01-01

    The space radiation environment can lead to extremely harsh operating conditions for on-board electronic box and systems. The characteristics of the radiation environment are highly dependent on the type of mission (date, duration and orbit). Radiation accelerates the aging of the electronic parts and material and can lead to a degradation of electrical performance; it can also create transient phenomena on parts. Such damage at the part level can induce damage or functional failure at electronic box, subsystem, and system levels. A rigorous methodology is needed to ensure that the radiation environment does not compromise the functionality and performance of the electronics during the system life. This methodology is called hardness assurance. It consists of those activities undertaken to ensure that the electronic piece parts placed in the space system perform to their design specifications after exposure to the space environment. It deals with system requirements, environmental definitions, part selection, part testing, shielding and radiation tolerant design. All these elements should play together in order to produce a system tolerant to.the radiation environment. An overview of the different steps of a space system hardness assurance program is given in section 2. In order to define the mission radiation specifications and compare these requirements to radiation test data, a detailed knowledge of the space environment and the corresponding electronic device failure mechanisms is required. The presentation by J. Mazur deals with the Earth space radiation environment as well as the internal environment of a spacecraft. The presentation by J. Schwank deals with ionization effects, and the presentation by T. Weatherford deals with Single particle Event Phenomena (SEP) in semiconductor devices and microcircuits. These three presentations provide more detailed background to complement the sections 3 and 4. Part selection and categorization are discussed in section

  15. Long-distance transmission of light in a scintillator-based radiation detector

    DOEpatents

    Dowell, Jonathan L.; Talbott, Dale V.; Hehlen, Markus P.

    2017-07-11

    Scintillator-based radiation detectors capable of transmitting light indicating the presence of radiation for long distances are disclosed herein. A radiation detector can include a scintillator layer and a light-guide layer. The scintillator layer is configured to produce light upon receiving incident radiation. The light-guide layer is configured to receive light produced by the scintillator layer and either propagate the received light through the radiation detector or absorb the received light and emit light, through fluorescence, that is propagated through the radiation detector. A radiation detector can also include an outer layer partially surrounding the scintillator layer and light-guide layer. The index of refraction of the light-guide layer can be greater than the index of refraction of adjacent layers.

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

    DOEpatents

    Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

    1989-02-07

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

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

    DOEpatents

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

    1987-02-27

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

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

    DOEpatents

    Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

    1989-01-01

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

  19. Observation of hard radiations in a laboratory atmospheric high-voltage discharge

    NASA Astrophysics Data System (ADS)

    Agafonov, A. V.; Bogachenkov, V. A.; Chubenko, A. P.; Oginov, A. V.; Rodionov, A. A.; Rusetskiy, A. S.; Ryabov, V. A.; Shepetov, A. L.; Shpakov, K. V.

    2017-04-01

    The new results concerning neutron emission detection from a laboratory high-voltage discharge in the air are presented. Data were obtained with a combination of plastic scintillation detectors and 3He-filled counters of thermal neutrons. Strong dependence of the hard x-ray and neutron radiation appearance on the field strength near electrodes, which is determined by their form, was found. We have revealed a more sophisticated temporal structure of the neutron bursts observed during electric discharge.

  20. Phoswich scintillator for proton and gamma radiation of high energy

    SciTech Connect

    Tengblad, O.; Borge, M. J. G.; Briz, J. A.; Carmona-Gallardo, M.; Cruz, C.; Gugliermina, V.; Nacher, E.; Perea, A.; Sanchez del Rio, J.; Nieves, M. Turrion; Nilsson, T.; Johansson, H. T.; Bergstroem, J.; Blomberg, E.; Buelling, A.; Gallneby, E.; Hagdahl, J.; Jansson, L.; Jareteg, K.; Masgren, R.; and others

    2011-11-30

    We present here a Phoswich scintillator design to achieve both high resolution gamma ray detection, and good efficiency for high energy protons. There are recent developments of new high resolution scintillator materials. Especially the LaBr3(Ce) and LaCl3(Ce) crystals have very good energy resolution in the order of 3% for 662 keV gamma radiation. In addition, these materials exhibit a very good light output (63 and 32 photons/keV respectively).A demonstrator detector in the form of an Al cylinder of 24 mm diameter and a total length of 80 mm with 2 mm wall thickness, containing a LaBr3(Ce) crystal of 20 mm diameter and 30 mm length directly coupled to a LaCl3(Ce) crystal of 50 mm length, and closed with a glass window of 5 mm, was delivered by Saint Gobain. To the glass window a Hamamatsu R5380 Photomultiplier tube (PMT) was coupled using silicon optical grease.

  1. Design and development of hard x-ray imaging detector using scintillator and Si photomultiplier

    NASA Astrophysics Data System (ADS)

    Goyal, S. K.; Naik, Amisha P.; Mithun, N. P. S.; Vadawale, S. V.; Acharya, Y. B.; Patel, A. R.; Ladiya, T.; Devashrayee, Niranjan M.

    2016-07-01

    There are various astrophysical phenomena which are of great importance and interest such as stellar explosions, Gamma ray bursts etc. There is also a growing interest in exploring the celestial sources in hard X-rays. High sensitive instruments are essential to perform the detailed studies of these cosmic accelerators and explosions. Hard X-ray imaging detectors having high absorption efficiency and mm spatial resolution are the key requirements to locate the generation of these astrophysical phenomenon. We hereby present a detector module which consists of a single CsI scintillation detector of size 15 x 15 x 3 mm3. The photon readout is done using an array of Silicon Photomultipliers (SiPMs). SiPM is a new development in the field of photon detection and can be described as 2D array of small (hundreds of μm2) avalanche photodiodes. We have achieved a spatial resolution of 0.5 mm with our initial setup. By using the array of these detector modules, we can build the detector with a large sensitive area with a very high spatial resolution. This paper presents the experimental details for single detector module using CsI (Tl) scintillator and SiPM and also presents the preliminary results of energy and position measurement. The GEANT4 simulation has also been carried out for the same geometry.

  2. Radiation Hardness Assurance (RHA) for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Buchner, Stephen

    2007-01-01

    This presentation discusses radiation hardness assurance (RHA) for space systems, providing both the programmatic aspects of RHA and the RHA procedure. RHA consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the space radiation environment. RHA also pertains to environment definition, part selection, part testing, spacecraft layout, radiation tolerant design, and mission/system/subsystems requirements. RHA procedure consists of establishing mission requirements, defining and evaluating the radiation hazard, selecting and categorizing the appropriate parts, and evaluating circuit response to hazard. The RHA approach is based on risk management and is confined only to parts, it includes spacecraft layout, system/subsystem/circuit design, and system requirements and system operations. RHA should be taken into account in the early phases of a program including the proposal and feasibility analysis phases.

  3. Using LEDs to stimulate the recovery of radiation damage to plastic scintillators

    NASA Astrophysics Data System (ADS)

    Wetzel, J.; Tiras, E.; Bilki, B.; Onel, Y.; Winn, D.

    2017-03-01

    In this study, we consider using LEDs to stimulate the recovery of scintillators damaged from radiation in high radiation environments. We irradiated scintillating tiles of polyethylene naphthalate (PEN), Eljen brand EJ-260 (EJN), an overdoped EJ-260 (EJ2P), and a lab-produced elastomer scintillator (ES) composed of p-terphenyl (ptp) in epoxy. Two different high-dose irradiations took place, with PEN dosed to 100 kGy, and the others to 78 kGy. We found that the 'blue' scintillators (PEN and ES) recovered faster and maximally higher with LEDs than without. Conversely exposing the 'green' scintillators (EJ-260) to LED light had a nearly negligible effect on the recovery. We hypothesize that the 'green' scintillators require wavelengths that match their absorption and emission spectra for LED stimulated recovery.

  4. Organic liquid scintillation detector shape and volume impact on radiation portal monitors

    NASA Astrophysics Data System (ADS)

    Paff, Marc G.; Clarke, Shaun D.; Pozzi, Sara A.

    2016-07-01

    We have developed and tested a radiation portal monitor using organic liquid scintillation detectors. In order to optimize our system designs, neutron measurements were carried out with three organic liquid scintillation detectors of different shapes and sizes, along with a 3He radiation portal monitor (RPM) as a reference. The three liquids tested were a 7.62 cm diameter by 7.62 cm length cylindrical active volume organic liquid scintillation detector, a 12.7 cm diameter by 12.7 cm length cylindrical active volume organic liquid scintillation detector, and a 25 cm by 25 cm by 10 cm "paddle" shaped organic liquid scintillation detector. Background and Cf-252 neutron measurements were recorded to allow for a comparison of neutron intrinsic efficiencies as well as receiver operating characteristics (ROC) curves between detectors. The 12.7 cm diameter cylindrical active volume organic liquid scintillation detector exhibited the highest intrinsic neutron efficiency (54%) of all three liquid scintillators. An ROC curve analysis for a heavily moderated Cf-252 measurement showed that using the 12.7 cm diameter by 12.7 cm length cylindrical active volume Eljen EJ309 organic liquid scintillation detector would result in the fewest needed detector units in order to achieve a near 100% positive neutron alarm rate while maintaining a better than 1 in 10,000 false alarm rate on natural neutron background. A small number of organic liquid scintillation detectors could therefore be a valid alternative to 3He in some RPM applications.

  5. Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources

    PubMed Central

    Rutherford, Michael E.; Chapman, David J.; White, Thomas G.; Drakopoulos, Michael; Rack, Alexander; Eakins, Daniel E.

    2016-01-01

    The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits). PMID:27140147

  6. Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources.

    PubMed

    Rutherford, Michael E; Chapman, David J; White, Thomas G; Drakopoulos, Michael; Rack, Alexander; Eakins, Daniel E

    2016-05-01

    The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits).

  7. Spectral discrimination of Cerenkov radiation in scintillating dosimeters.

    PubMed

    Frelin, A M; Fontbonne, J M; Ban, G; Colin, J; Labalme, M; Batalla, A; Isambert, A; Vela, A; Leroux, T

    2005-09-01

    Radiation therapy accelerators require highly accurate dose deposition and the output must be monitored frequently and regularly. Ionization chambers are the primary tool for this control, but their size, their high voltage needed, and the correction needed for electrons make them unsuitable for use during patient treatment. We have developed a small (1-mm-diam and 1-mm-long active part), flexible, and water-equivalent dosimeter. It is suitable for photon and electron beams without corrections, and performs on line dose measurements. This detector is based on only one scintillating fiber and a CCD camera. A new signal processing is used to remove the effect of Cerenkov radiation background, which only requires a preliminary calibration. Central-axis depth-dose distribution comparisons have been achieved with standard ionization chambers, over a range from 8 to 25 MV photons and from 6 to 21 MeV electrons in order to validate this calibration. Results show a very good agreement, with less than 1% difference between the two detectors.

  8. Dealing with Cerenkov radiation generated in organic scintillator dosimeters by bremsstrahlung beams

    NASA Astrophysics Data System (ADS)

    Clift, M. A.; Sutton, R. A.; Webb, D. V.

    2000-05-01

    An organic scintillator detector system has been developed for radiotherapy bremsstrahlung dosimetry. The scintillators are connected to photodiodes by light pipes as the photodiodes must be removed and shielded from the incident radiation. The photodiodes see visible and near-visible light emissions from the scintillator as well as Cerenkov and fluorescence radiation that has been generated and trapped in the scintillator and light pipe. The Cerenkov and fluorescence radiation limits the accuracy of the dosimeter. This work examines a range of methods for diminishing the signal contribution of Cerenkov and fluorescence radiation while optimizing the scintillator signal. Three methods of achieving these goals have been used. They are: reflective coatings on the scintillator, long-wavelength-emitting scintillators used in conjunction with the photodiode, and absorptive filters placed between the light guide and photodiode. The contribution of the Cerenkov radiation to the light seen by the photodiode has been modelled and the model predictions have been tested using bremsstrahlung beams of peak energy between 13 and 20 MV, showing agreement with measurement.

  9. R&D Studies on Radiation Hard Wavelength Shifting Fiber for CMS Hadronic Endcap Calorimeter Upgrade

    NASA Astrophysics Data System (ADS)

    Neuhaus, John

    2009-11-01

    The Hadronic Endcap (HE) calorimeters of the CMS experiment cover the pseudorapidity range of 1.4 to 3 on both sides of the CMS detector, contributing to superior jet and missing transverse energy resolutions. As the integrated luminosity of the LHC increases, the scintillator tiles used in the CMS Hadronic Endcap calorimeter will lose their efficiency. Here, we propose to replace the scintillator tiles in high radiation area with ``radiation hard'' quartz plates. To increase the light collection efficiency, the generated Cerenkov photons are collected by UV absorbing wavelength shifting (WLS) fibers. Our previous study has shown that quartz plates and plastic wavelength shifting fibers can be used as an effective calorimeter. However there is no radiation hard WLS fiber commercially available. Here we summarize the R&D studies on constructing a radiation hard WLS fiber prototype in University of Iowa CMS Laboratories. The results from the tests performed on quartz fibers treated with p-Terphenyl, as well as the Geant4 simulations of this prototype are presented.

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

    SciTech Connect

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

    2010-01-01

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

  11. Response of organic liquid scintillators to fast neutrons and gamma radiation

    NASA Astrophysics Data System (ADS)

    Hoertz, Paul G.; Mills, Karmann; Davis, Lynn; Baldasaro, Nicholas; Gupta, Vijay

    2013-03-01

    Liquid organic scintillators are cocktails of aromatic fluorophores in an aromatic solvent. They find widespread use in Liquid Scintillation Counters with applications in medical diagnostics as well as fundamental nuclear and particle physics. Ultima Gold™ XR, a commercially available organic liquid scintillator from Perkin Elmer, can be used in both aqueous and non-aqueous systems and is typically used for beta detection in medical diagnostics. Its performance under gamma radiation and neutron radiation is less well-characterized. Special and normal Ultima Gold™ XR liquid scintillators were exposed in separate experiments to fast neutrons and high energy photons from a nuclear reactor and to gamma rays from a Co-60 source. To perform the measurements in the radiation chamber, a custom light collection system consisting of a fiber optic cable, spectrometer and a diffuse reflecting optical cavity was fabricated. Advanced calibration procedures, traceable to NIST standards, were developed to determine photon fluxes and flux densities of the scintillators under ionizing radiation conditions. The scintillator emission spectra under gamma radiation from a Co-60 source and neutron radiation from a pool-type nuclear reactor were recorded and compared. Results on the spectrometer design and comparison of the spectra under different exposure are presented.

  12. Radiation Hard Active Media R&D for CMS Hadron Endcap Calorimetry

    NASA Astrophysics Data System (ADS)

    Tiras, Emrah; CMS-HCAL Collaboration

    2015-04-01

    The High Luminosity LHC era imposes unprecedented radiation conditions on the CMS detectors targeting a factor of 5-10 higher than the LHC design luminosity. The CMS detectors will need to be upgraded in order to withstand these conditions yet maintain/improve the physics measurement capabilities. One of the upgrade options is reconstructing the CMS Endcap Calorimeters with a shashlik design electromagnetic section and replacing active media of the hadronic section with radiation-hard scintillation materials. In this context, we have studied various radiation-hard materials such as Polyethylene Naphthalate (PEN), Polyethylene Terephthalate (PET), HEM and quartz plates coated with various organic materials such as p-Terphenyl (pTp), Gallium doped Zinc Oxide (ZnO:Ga) and Anthracene. Here we discuss the related test beam activities, laboratory measurements and recent developments.

  13. Radiation Hardness of dSiPM Sensors in a Proton Therapy Radiation Environment

    NASA Astrophysics Data System (ADS)

    Diblen, Faruk; Buitenhuis, Tom; Solf, Torsten; Rodrigues, Pedro; van der Graaf, Emiel; van Goethem, Marc-Jan; Brandenburg, Sytze; Dendooven, Peter

    2017-07-01

    In vivo verification of dose delivery in proton therapy by means of positron emission tomography (PET) or prompt gamma imaging is mostly based on fast scintillation detectors. The digital silicon photomultiplier (dSiPM) allows excellent scintillation detector timing properties and is thus being considered for such verification methods. We present here the results of the first investigation of radiation damage to dSiPM sensors in a proton therapy radiation environment. Radiation hardness experiments were performed at the AGOR cyclotron facility at the KVI-Center for Advanced Radiation Technology, University of Groningen. A 150-MeV proton beam was fully stopped in a water target. In the first experiment, bare dSiPM sensors were placed at 25 cm from the Bragg peak, perpendicular to the beam direction, a geometry typical for an in situ implementation of a PET or prompt gamma imaging device. In the second experiment, dSiPM-based PET detectors containing lutetium yttrium orthosilicate scintillator crystal arrays were placed at 2 and 4 m from the Bragg peak, perpendicular to the beam direction; resembling an in-room PET implementation. Furthermore, the experimental setup was simulated with a Geant4-based Monte Carlo code in order to determine the angular and energy distributions of the neutrons and to determine the 1-MeV equivalent neutron fluences delivered to the dSiPM sensors. A noticeable increase in dark count rate (DCR) after an irradiation with about 108 1-MeV equivalent neutrons/cm2 agrees with observations by others for analog SiPMs, indicating that the radiation damage occurs in the single photon avalanche diodes and not in the electronics integrated on the sensor chip. It was found that in the in situ location, the DCR becomes too large for successful operation after the equivalent of a few weeks of use in a proton therapy treatment room (about 5 × 1013 protons). For PET detectors in an in-room setup, detector performance was unchanged even after an

  14. Fault-Tolerant, Radiation-Hard DSP

    NASA Technical Reports Server (NTRS)

    Czajkowski, David

    2011-01-01

    Commercial digital signal processors (DSPs) for use in high-speed satellite computers are challenged by the damaging effects of space radiation, mainly single event upsets (SEUs) and single event functional interrupts (SEFIs). Innovations have been developed for mitigating the effects of SEUs and SEFIs, enabling the use of very-highspeed commercial DSPs with improved SEU tolerances. Time-triple modular redundancy (TTMR) is a method of applying traditional triple modular redundancy on a single processor, exploiting the VLIW (very long instruction word) class of parallel processors. TTMR improves SEU rates substantially. SEFIs are solved by a SEFI-hardened core circuit, external to the microprocessor. It monitors the health of the processor, and if a SEFI occurs, forces the processor to return to performance through a series of escalating events. TTMR and hardened-core solutions were developed for both DSPs and reconfigurable field-programmable gate arrays (FPGAs). This includes advancement of TTMR algorithms for DSPs and reconfigurable FPGAs, plus a rad-hard, hardened-core integrated circuit that services both the DSP and FPGA. Additionally, a combined DSP and FPGA board architecture was fully developed into a rad-hard engineering product. This technology enables use of commercial off-the-shelf (COTS) DSPs in computers for satellite and other space applications, allowing rapid deployment at a much lower cost. Traditional rad-hard space computers are very expensive and typically have long lead times. These computers are either based on traditional rad-hard processors, which have extremely low computational performance, or triple modular redundant (TMR) FPGA arrays, which suffer from power and complexity issues. Even more frustrating is that the TMR arrays of FPGAs require a fixed, external rad-hard voting element, thereby causing them to lose much of their reconfiguration capability and in some cases significant speed reduction. The benefits of COTS high

  15. Radiation Hard AlGaN Detectors and Imager

    SciTech Connect

    2012-05-01

    Radiation hardness of AlGaN photodiodes was tested using a 65 MeV proton beam with a total proton fluence of 3x10{sup 12} protons/cm{sup 2}. AlGaN Deep UV Photodiode have extremely high radiation hardness. These new devices have mission critical applications in high energy density physics (HEDP) and space explorations. These new devices satisfy radiation hardness requirements by NIF. NSTec is developing next generation AlGaN optoelectronics and imagers.

  16. Radiation-resistant composite scintillators based on GSO and GPS grains

    NASA Astrophysics Data System (ADS)

    Boyarintsev, A. Yu.; Galunov, N. Z.; Gerasymov, Ia. V.; Karavaeva, N. L.; Krech, A. V.; Levchuk, L. G.; Popov, V. F.; Sidletskiy, O. Ts.; Sorokin, P. V.; Tarasenko, O. A.

    2017-01-01

    The effect of irradiation on the scintillation light output, optical transmittance, and luminescent spectra of composite scintillators based on grains of single crystals Gd2SiO5:Ce (GSO) and Gd2Si2O7:Ce (GPS) is studied. The dielectric gel Sylgard-184 is the base and the binder for the grains inside the composite scintillator. The paper presents and analyzes the results obtained for the scintillators exposed by 10 MeV electrons from the linear electron accelerator at room temperature. The exposure doses D≤250 Mrad. The dose rate is 0.2 or 1500 Mrad/h. The study has shown that the composite scintillators based on the grains of GSO and GPS are radiation-resistant over the range of the irradiation.

  17. Seeing the invisible: Direct visualization of therapeutic radiation beams using air scintillation

    SciTech Connect

    Fahimian, Benjamin; Türkcan, Silvan; Kapp, Daniel S.; Pratx, Guillem; Ceballos, Andrew

    2014-01-15

    Purpose: To assess whether air scintillation produced during standard radiation treatments can be visualized and used to monitor a beam in a nonperturbing manner. Methods: Air scintillation is caused by the excitation of nitrogen gas by ionizing radiation. This weak emission occurs predominantly in the 300–430 nm range. An electron-multiplication charge-coupled device camera, outfitted with an f/0.95 lens, was used to capture air scintillation produced by kilovoltage photon beams and megavoltage electron beams used in radiation therapy. The treatment rooms were prepared to block background light and a short-pass filter was utilized to block light above 440 nm. Results: Air scintillation from an orthovoltage unit (50 kVp, 30 mA) was visualized with a relatively short exposure time (10 s) and showed an inverse falloff (r{sup 2} = 0.89). Electron beams were also imaged. For a fixed exposure time (100 s), air scintillation was proportional to dose rate (r{sup 2} = 0.9998). As energy increased, the divergence of the electron beam decreased and the penumbra improved. By irradiating a transparent phantom, the authors also showed that Cherenkov luminescence did not interfere with the detection of air scintillation. In a final illustration of the capabilities of this new technique, the authors visualized air scintillation produced during a total skin irradiation treatment. Conclusions: Air scintillation can be measured to monitor a radiation beam in an inexpensive and nonperturbing manner. This physical phenomenon could be useful for dosimetry of therapeutic radiation beams or for online detection of gross errors during fractionated treatments.

  18. Detection of gamma-neutron radiation by solid-state scintillation detectors. Detection of gamma-neutron radiation by novel solid-state scintillation detectors

    SciTech Connect

    Ryzhikov, V.; Grinyov, B.; Piven, L.; Onyshchenko, G.; Sidletskiy, O.; Naydenov, S.; Pochet, T.; Smith, C.

    2015-07-01

    It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role of detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n'γ) reactions towards

  19. Radiation and Temperature Hard Multi-Pixel Avalanche Photodiodes

    NASA Technical Reports Server (NTRS)

    Bensaoula, Abdelhak (Inventor); Starikov, David (Inventor); Pillai, Rajeev (Inventor)

    2017-01-01

    The structure and method of fabricating a radiation and temperature hard avalanche photodiode with integrated radiation and temperature hard readout circuit, comprising a substrate, an avalanche region, an absorption region, and a plurality of Ohmic contacts are presented. The present disclosure provides for tuning of spectral sensitivity and high device efficiency, resulting in photon counting capability with decreased crosstalk and reduced dark current.

  20. Development of a radiation-hard photomultiplier tube

    NASA Technical Reports Server (NTRS)

    Birnbaum, M. M.; Bunker, R. L.; Roderick, J.; Stephenson, K.

    1984-01-01

    In a radiation-hard photomultiplier tube (PMT) such as has been developed for stabilization of the Galileo spacecraft as it goes through the Jovian high energy radiation belts, the primary effects of high energy electron and proton radiation that must be resisted are the production of fluorescence and Cerenkov emission. The present PMT envelope is ceramic rather than glass, and employs a special, electron-focusing design which will collect, accelerate and amplify electrons only from desired photocathode areas. Tests in a Co-60 radiation facility have shown that the radiation-hard PMT produces less than 2.5 percent of the radiation noise of a standard PMT.

  1. Development of a radiation-hard photomultiplier tube

    NASA Technical Reports Server (NTRS)

    Birnbaum, M. M.; Bunker, R. L.; Roderick, J.; Stephenson, K.

    1984-01-01

    In a radiation-hard photomultiplier tube (PMT) such as has been developed for stabilization of the Galileo spacecraft as it goes through the Jovian high energy radiation belts, the primary effects of high energy electron and proton radiation that must be resisted are the production of fluorescence and Cerenkov emission. The present PMT envelope is ceramic rather than glass, and employs a special, electron-focusing design which will collect, accelerate and amplify electrons only from desired photocathode areas. Tests in a Co-60 radiation facility have shown that the radiation-hard PMT produces less than 2.5 percent of the radiation noise of a standard PMT.

  2. Test bench development for the radiation Hard GBTX ASIC

    NASA Astrophysics Data System (ADS)

    Leitao, P.; Feger, S.; Porret, D.; Baron, S.; Wyllie, K.; Barros Marin, M.; Figueiredo, D.; Francisco, R.; Da Silva, J. C.; Grassi, T.; Moreira, P.

    2015-01-01

    This paper presents the development of the GBTX radiation hard ASIC test bench. Developed for the LHC accelerator upgrade programs, the GBTX implements a bidirectional 4.8 Gb/s link between the radiation hard on-detector custom electronics and the off-detector systems. The test bench was used for functional testing of the GBTX and to evaluate its performance in a radiation environment, by conducting Total Ionizing Dose and Single-Event Upsets tests campaigns.

  3. LiCaAlF6 scintillators in neutron and gamma radiation fields

    NASA Astrophysics Data System (ADS)

    Viererbl, L.; Klupák, V.; Vinš, M.; Koleška, M.; Šoltés, J.; Yoshikawa, A.; Nikl, M.

    2016-09-01

    Intentionally doped LiCaAlF6 (LiCAF) single crystals are prospective scintillators, especially for thermal neutron detection through the 6Li(n,t)4He nuclear reaction. Four different LiCAF scintillator samples were tested in various neutron and gamma fields. Two of the tested samples were LiCAF:Eu and LiCAF:Eu,Na single crystals, and another two samples were made of LiCAF:Eu micro crystals dispersed in transparent rubber, with different rubber dimensions. All LiCAF samples contain lithium enriched to6Li. A plutonium-beryllium source was used as a neutron source. The neutron spectrum was modified by moderator and filter to get different ratios between thermal, epithermal and fast neutron fluence rates. The MCNP code was used for calculations of the fluence rates for different configurations. Radionuclides 137Cs and 60Co were applied as gamma radiation sources. The light signal from the scintillator was evaluated with a photomultiplier and a multichannel analyzer. The purpose of this work was to study the characteristics of LiCAF scintillators, especially the ability to discriminate signals from neutron and gamma radiation, which is the basic scintillator condition for neutron detection in mixed neutron-gamma radiation fields. Generally, the discrimination can be done by the pulse height and/or the pulse shape of the evaluated signals. Both methods can be used for a LiCAF scintillator. However, only the pulse height discrimination method is discussed in this paper. The possibility of fast neutron detection with LiCAF scintillators was also tested.

  4. Plastic Scintillators for Pulse Shape Discrimination of Particle Types in Radiation Detection

    NASA Astrophysics Data System (ADS)

    Hajagos, Tibor Jacob

    Organic scintillators have a long history in the field of radiation detection, dating back to some of the earliest studies of organic photophysics and optoelectronic properties. In particular, plastics have come to dominate the commercial market for organic scintillators, due to their low cost and ease of use and manufacturing, and more notably in spite of their poorer performance in many metrics. While there has been decades of active research since their inception, little progress has been made to improve upon the now well established compositions of commercial plastics, a notable exception being the recent development of plastic scintillators capable of pulse shape discrimination (PSD) of n/gamma radiation, which is of particular interest among governments and industry for the detection of illicit nuclear material and weapons. In recent years, much attention has been paid towards the study of luminescent organic materials, in particular due to the invention and widespread adoption of organic light emitting diode (OLED) based electronic devices, and the knowledge and lessons that have been fundamental to such fields have recently begun to be adopted by the organic scintilator community. In this work, new approaches to the design of both plastic scintillator components, and of the materials as a whole, are described, with particular emphasis paid towards the design and synthesis of small molecule scintillating dyes that are specifically tailored towards the development of PSD-capable plastic scintilators. In the first of these approaches, the design and synthesis of a highly soluble and polymerizable derivative of 9,10-diphenylanthracene is described, and the properties of plastic scintilators fabricated from this dye when copolymerized with poly(vinyl toluene) were investigated. This particular approach was used to demonstrate a proof-of-concept of PSD in highly loaded plastics stabilized through copolymerization of the primary dye, a strategy conceived to

  5. Statistical Modeling for Radiation Hardness Assurance: Toward Bigger Data

    NASA Technical Reports Server (NTRS)

    Ladbury, R.; Campola, M. J.

    2015-01-01

    New approaches to statistical modeling in radiation hardness assurance are discussed. These approaches yield quantitative bounds on flight-part radiation performance even in the absence of conventional data sources. This allows the analyst to bound radiation risk at all stages and for all decisions in the RHA process. It also allows optimization of RHA procedures for the project's risk tolerance.

  6. Radiation imaging with a new scintillator and a CMOS camera

    NASA Astrophysics Data System (ADS)

    Kurosawa, S.; Shoji, Y.; Pejchal, J.; Yokota, Y.; Yoshikawa, A.

    2014-07-01

    A new imaging system consisting of a high-sensitivity complementary metal-oxide semiconductor (CMOS) sensor, a microscope and a new scintillator, Ce-doped Gd3(Al,Ga)5O12 (Ce:GAGG) grown by the Czochralski process, has been developed. The noise, the dark current and the sensitivity of the CMOS camera (ORCA-Flash4.0, Hamamatsu) was revised and compared to a conventional CMOS, whose sensitivity is at the same level as that of a charge coupled device (CCD) camera. Without the scintillator, this system had a good position resolution of 2.1 ± 0.4 μm and we succeeded in obtaining the alpha-ray images using 1-mm thick Ce:GAGG crystal. This system can be applied for example to high energy X-ray beam profile monitor, etc.

  7. Radiation effects on wavelength shifting fibers used with liquid scintillators

    SciTech Connect

    Ables, E.; Armatis, P.; Bionta, R.; Britt, H.; Clamp, O.; Cochran, C.; Graham, G.; Lowry, M.; Masquelier, D.; Skulina, K.; Wuest, C.; Bolen, L.; Cremaldi, L.; Harper, S.; Moore, B.; Quinn, B.; Reidy, J.; Zhou, J.; Croft, L.; Piercey, R.; Bauer, M.L.; Bishop, B.L.; Cohn, H.O.; Gabriel, T.A.; Gordeev, A.; Kamyshkov, Yu.; Lillei, R.A.; Plasil, F.; Read, K.; Rennich, M.J.; Savin, A.; Shmakov, K.; Singeltary, B.H.; Smirnov, A.; Tarkovsky, E.; Todd, R.A.; Young, K.G.; Berridge, S.C.; Bugg, W.M.; Handler, T.; Pisharody, M.; Aziz, T.; Banerjee, S.; Chendvankar, S.R.; Ganfuli, S.N.; Malhotra, K.; Mazumdar, K.; Raghavan, R.; Shankar, K.; Sudhakar, K.; Tonwar, S.C.; Arefiev, A.; Baranov, O.; Efremenko, Yu.; Gorodkov, Yu.; Malinin, A.; Nikitin, A.; Markizov, V.; Onoprienko, D.; Rozjkov, A.; Shoumilov, E.; Shoutko, V.

    1992-06-01

    The chemical compatibility of wave length shifting fibers with several liquid scintillators has been investigated. Based on systematic characterization of the behavior of the BC-517 family, a time of life of 70{endash}450 years was estimated for the polystyrene based wave length shifting fiber in BC-517P scintillator. WLS (wavelength shifting) fibers irradiated continuously to a dose of 6.4 Mrads (at .377Mrad/hr of Co-60) were observed to decrease from 100% to 5% transmission; however, after 100 hours of annealing, the transmission increased to 90%. Geant simulations of a simplified calorimeter located behind a BaF2 electromagnetic calorimeter for the GEM detector at SSC showed that the constant term in the energy resolution will change from 1.8 to 2.9 in five years at 10{star}{star}34 luminosity for psuedorapidity eta=3.

  8. Liquid scintillator tiles for calorimetry

    NASA Astrophysics Data System (ADS)

    Amouzegar, M.; Belloni, A.; Bilki, B.; Calderon, J.; De Barbaro, P.; Eno, S. C.; Hatakeyama, K.; Hirschauer, J.; Jeng, G. Y.; Pastika, N. J.; Pedro, K.; Rumerio, Paolo; Samuel, J.; Sharp, E.; Shin, Y. H.; Tiras, E.; Vishnevskiy, D.; Wetzel, J.; Yang, Z.; Yao, Y.; Youn, S. W.

    2016-11-01

    Future experiments in high energy and nuclear physics may require large, inexpensive calorimeters that can continue to operate after receiving doses of 50 Mrad or more. The light output of liquid scintillators suffers little degradation under irradiation. However, many challenges exist before liquids can be used in sampling calorimetry, especially regarding developing a packaging that has sufficient efficiency and uniformity of light collection, as well as suitable mechanical properties. We present the results of a study of a scintillator tile based on the EJ-309 liquid scintillator using cosmic rays and test beam on the light collection efficiency and uniformity, and some preliminary results on radiation hardness.

  9. Liquid scintillator tiles for calorimetry

    SciTech Connect

    Amouzegar, M.; Belloni, A.; Bilki, B.; Calderon, J.; Barbaro, P. De; Eno, S. C.; Hatakeyama, K.; Hirschauer, J.; Jeng, G. Y.; Pastika, N. J.; Pedro, K.; Rumerio, Paolo; Samuel, J.; Sharp, E.; Shin, Y. H.; Tiras, E.; Vishnevskiy, D.; Wetzel, J.; Yang, Z.; Yao, Y.; Youn, S. W.

    2016-11-28

    Future experiments in high energy and nuclear physics may require large, inexpensive calorimeters that can continue to operate after receiving doses of 50 Mrad or more. Also, the light output of liquid scintillators suffers little degradation under irradiation. However, many challenges exist before liquids can be used in sampling calorimetry, especially regarding developing a packaging that has sufficient efficiency and uniformity of light collection, as well as suitable mechanical properties. We present the results of a study of a scintillator tile based on the EJ-309 liquid scintillator using cosmic rays and test beam on the light collection efficiency and uniformity, and some preliminary results on radiation hardness.

  10. Device and Method of Scintillating Quantum Dots for Radiation Imaging

    NASA Technical Reports Server (NTRS)

    Burke, Eric R. (Inventor); DeHaven, Stanton L. (Inventor); Williams, Phillip A. (Inventor)

    2017-01-01

    A radiation imaging device includes a radiation source and a micro structured detector comprising a material defining a surface that faces the radiation source. The material includes a plurality of discreet cavities having openings in the surface. The detector also includes a plurality of quantum dots disclosed in the cavities. The quantum dots are configured to interact with radiation from the radiation source, and to emit visible photons that indicate the presence of radiation. A digital camera and optics may be used to capture images formed by the detector in response to exposure to radiation.

  11. Radiation response of inorganic scintillators: Insights from Monte Carlo simulations

    SciTech Connect

    Prange, Micah P.; Wu, Dangxin; Xie, YuLong; Campbell, Luke W.; Gao, Fei; Kerisit, Sebastien N.

    2014-07-24

    The spatial and temporal scales of hot particle thermalization in inorganic scintillators are critical factors determining the extent of second- and third-order nonlinear quenching in regions with high densities of electron-hole pairs, which, in turn, leads to the light yield nonproportionality observed, to some degree, for all inorganic scintillators. Therefore, kinetic Monte Carlo simulations were performed to calculate the distances traveled by hot electrons and holes as well as the time required for the particles to reach thermal energy following γ-ray irradiation. CsI, a common scintillator from the alkali halide class of materials, was used as a model system. Two models of quasi-particle dispersion were evaluated, namely, the effective mass approximation model and a model that relied on the group velocities of electrons and holes determined from band structure calculations. Both models predicted rapid electron-hole pair recombination over short distances (a few nanometers) as well as a significant extent of charge separation between electrons and holes that did not recombine and reached thermal energy. However, the effective mass approximation model predicted much longer electron thermalization distances and times than the group velocity model. Comparison with limited experimental data suggested that the group velocity model provided more accurate predictions. Nonetheless, both models indicated that hole thermalization is faster than electron thermalization and thus is likely to be an important factor determining the extent of third-order nonlinear quenching in high-density regions. The merits of different models of quasi-particle dispersion are also discussed.

  12. Design of new polymers to improve radiation stability of plastic scintillators

    SciTech Connect

    Barashkov, N.; Korotkikh, N.; Novikova, T.; Markley, F.; Pla-Dalmau, A.; Foster, G.; Rivard, M.

    1993-11-01

    Diffusion enhancers have been used to increase the radiation stability of scintillators. There is a danger that such additions will also allow the scintillation dyes to diffuse out of the matrix. Covalent bonding of the dyes into the matrix would eliminate any luminophore migration. We have demonstrated that dyes with vinyl and divinyl groups can be successfully bonded into a styrene matrix. Both primary and secondary luminophores have been bonded into the matrix and in several cases they have been compared with similar luminophores without the vinyl groups in otherwise identical compositions. In general the bonding does not greatly affect either the radiation stability of the composition or its light output, but is therefore proven to be an acceptable method of preventing luminophore migration. Scintillators with a base of aromatic or alicyclic epoxy resins have also been made with bonded luminophores. In these compositions the bonding is accomplished by using luminophores with one or two amine groups or epoxy groups. When using the amines, they are first prereacted with the epoxy resin and the modified epoxy is then cured with hexahydrophthalic anhydride or trimethoxyboroxine. The emission and absorption spectra of many of these reactive luminophores are given, along with the light outputs and radiation stability of the resulting scintilators.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-03-01

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

  15. Sustainably Sourced, Thermally Resistant, Radiation Hard Biopolymer

    NASA Technical Reports Server (NTRS)

    Pugel, Diane

    2011-01-01

    This material represents a breakthrough in the production, manufacturing, and application of thermal protection system (TPS) materials and radiation shielding, as this represents the first effort to develop a non-metallic, non-ceramic, biomaterial-based, sustainable TPS with the capability to also act as radiation shielding. Until now, the standing philosophy for radiation shielding involved carrying the shielding at liftoff or utilizing onboard water sources. This shielding material could be grown onboard and applied as needed prior to different radiation landscapes (commonly seen during missions involving gravitational assists). The material is a bioplastic material. Bioplastics are any combination of a biopolymer and a plasticizer. In this case, the biopolymer is a starch-based material and a commonly accessible plasticizer. Starch molecules are composed of two major polymers: amylase and amylopectin. The biopolymer phenolic compounds are common to the ablative thermal protection system family of materials. With similar constituents come similar chemical ablation processes, with the potential to have comparable, if not better, ablation characteristics. It can also be used as a flame-resistant barrier for commercial applications in buildings, homes, cars, and heater firewall material. The biopolymer is observed to undergo chemical transformations (oxidative and structural degradation) at radiation doses that are 1,000 times the maximum dose of an unmanned mission (10-25 Mrad), indicating that it would be a viable candidate for robust radiation shielding. As a comparison, the total integrated radiation dose for a three-year manned mission to Mars is 0.1 krad, far below the radiation limit at which starch molecules degrade. For electron radiation, the biopolymer starches show minimal deterioration when exposed to energies greater than 180 keV. This flame-resistant, thermal-insulating material is non-hazardous and may be sustainably sourced. It poses no hazardous

  16. Resonance hard radiation in a gas-loaded FEL

    SciTech Connect

    Gevorgian, L.A.

    1995-12-31

    The process of induced radiation under the condition when the relativistic beam oscillation frequency coincides with the plasma frequency of the FEL filling gas, is investigated. Such a resonance results in a giant enhancement of interaction between electrons and photons providing high gain in the hard FEL frequency region. Meanwhile the spectralwidth of the spontaneous radiation is broadened significantly. A method is proposed for maintaining the synchronism between the electron oscillation frequency and the medium plasma frequency, enabling to transform the electron energy into hard radiation with high efficiency.

  17. Neutron induced radiation damage of plastic scintillators for the upgrade of the Tile Calorimeter of the ATLAS detector.

    NASA Astrophysics Data System (ADS)

    Mdhluli, J. E.; Jivan, H.; Erasmus, R.; Davydov, Yu I.; Baranov, V.; Mthembu, S.; Mellado, B.; Sideras-Haddad, E.; Solovyanov, O.; Sandrock, C.; Peter, G.; Tlou, S.; Khanye, N.; Tjale, B.

    2017-07-01

    With the prediction that the plastic scintillators in the gap region of the Tile Calorimeter will sustain a significantly large amount of radiation damage during the HL-LHC run time, the current plastic scintillators will need to be replaced during the phase 2 upgrade in 2018. The scintillators in the gap region were exposed to a radiation environment of up to 10 kGy/year during the first run of data taking and with the luminosity being increased by a factor of 10, the radiation environment will be extremely harsh. We report on the radiation damage to the optical properties of plastic scintillators following irradiation using a neutron beam of the IBR-2 pulsed reactor in Joint Institute for Nuclear Research (JINR), Dubna. A comparison is drawn between polyvinyl toluene based commercial scintillators EJ200, EJ208 and EJ260 as well as polystyrene based scintillator from Kharkov. The samples were subjected to irradiation with high energy neutrons and a flux density range of 1 × 106-7.7 × 106. Light transmission, Raman spectroscopy, fluorescence spectroscopy and light yield testing was performed to characterize the damage induced in the samples. Preliminary results from the tests done indicate a minute change in the optical properties of the scintillators with further studies underway to gain a better understanding of the interaction between neutrons with plastic scintillators.

  18. Radiation Hard 0.13 Micron CMOS Library at IHP

    NASA Astrophysics Data System (ADS)

    Jagdhold, U.

    2013-08-01

    To support space applications we have developed an 0.13 micron CMOS library which should be radiation hard up to 200 krad. The article describes the concept to come to a radiation hard digital circuit and was introduces in 2010 [1]. By introducing new radiation hard design rules we will minimize IC-level leakage and single event latch-up (SEL). To reduce single event upset (SEU) we add two p-MOS transistors to all flip flops. For reliability reasons we use double contacts in all library elements. The additional rules and the library elements are integrated in our Cadence mixed signal design kit, “Virtuoso” IC6.1 [2]. A test chip is produced with our in house 0.13 micron BiCMOS technology, see Ref. [3]. As next step we will doing radiation tests according the european space agency (ESA) specifications, see Ref. [4], [5].

  19. The influence of neutron radiation damage on the optical properties of plastic scintillator UPS 923A

    NASA Astrophysics Data System (ADS)

    Mthembu, Skhathisomusa; Davydov, Yuri; Baranov, Vladimir; Mellado Garcia, Bruce; Mdhluli, Joyful; Sideras-Haddad, Elias

    2017-09-01

    Plastic scintillators are vital in the reconstruction of hadronic particle energy and tracks resulting from the collision of high energy particles in the Large Hadron Collider (LHC) at CERN. These plastic scintillators are exposed to harsh radiation environments and are susceptible to radiation damage. The effects of radiation damage on the transmittance, luminescence and light yield of Ukraine polystyrene-based scintillator UPS 923A were studied. Samples were irradiated with fast neutrons, of varying energies and fluences, using the IBR-2 reactor FLNP (Frank Laboratory for Nuclear Problems) at the Joint Institute for Nuclear Research. Results show a small change in the transmittance of the higher energy visible spectrum, and a noticeable change in the light yield of the samples as a result of the damage. There is no change observed on the luminescence as a result of radiation damage at studied fluences. The doses and uences of the neutrons shall be increased and changes in optical properties as a result of the radiation shall be further studied.

  20. Initial Nuclear Radiation Hardness Validation Test

    DTIC Science & Technology

    2008-11-03

    Measurement Accuracy Photocurrent Photocurrent Probes ±5% Gamma Dose **CaF 2 (Mn) TLD ±10% Gamma Radiation Pulse PIN Diode Compton ...1.02 and cGy(tissue)/cGy(CaF2) = 1.13, respectively. Each radiation pulse will be measured using a PIN or Compton diode and digitized on a transient...photocurrents produce secondary effects that include: a. Error generation in logic and analog circuits. b. Secondary photocurrents. TOP 1-2-618 3

  1. Synchrotron radiation hardness studies of PILATUS II.

    PubMed

    Sobott, B A; Broennimann, Ch; Eikenberry, E F; Dinapoli, R; Kraft, P; Taylor, G N; Willmott, P R; Schlepütz, C M; Rassool, R P

    2009-07-01

    A synchrotron beam has been used to investigate the radiation tolerance of a PILATUS II module. It has been demonstrated that radiation-induced threshold shifts become significant above 30 Mrad. Individual adjustment of pixel thresholds after irradiation enabled retention of standard behaviour in excess of 40 Mrad. This implies that a module can be continuously irradiated for in excess of 40 days at an individual pixel count rate of 10(6) counts s(-1).

  2. Optical transmission radiation damage and recovery stimulation of DSB: Ce3+ inorganic scintillation material

    NASA Astrophysics Data System (ADS)

    Borisevich, A.; Dormenev, V.; Korjik, M.; Kozlov, D.; Mechinsky, V.; Novotny, R. W.

    2015-02-01

    Recently, a new scintillation material DSB: Ce3+ was announced. It can be produced in a form of glass or nano-structured glass ceramics with application of standard glass production technology with successive thermal annealing. When doped with Ce3+, material can be applied as scintillator. Light yield of scintillation is near 100 phe/MeV. Un-doped material has a wide optical window from 4.5eV and can be applied to detect Cherenkov light. Temperature dependence of the light yield LY(T) is 0.05% which is 40 times less than in case of PWO. It can be used for detectors tolerant to a temperature variation between -20° to +20°C. Several samples with dimensions of 15x15x7 mm3 have been tested for damage effects on the optical transmission under irradiation with γ-quanta. It was found that the induced absorption in the scintillation range depends on the doping concentration and varies in range of 0.5-7 m-1. Spontaneous recovery of induced absorption has fast initial component. Up to 25% of the damaged transmission is recuperated in 6 hours. Afterwards it remains practically constant if the samples are kept in the dark. However, induced absorption is reduced by a factor of 2 by annealing at 50°C and completely removed in a short time when annealing at 100°C. A significant acceleration of the induced absorption recovery is observed by illumination with visible and IR light. This effect is observed for the first time in a Ce-doped scintillation material. It indicates, that radiation induced absorption in DSB: Ce scintillation material can be retained at the acceptable level by stimulation with light in a strong irradiation environment of collider experiments.

  3. Photon dosimetry using plastic scintillators in pulsed radiation fields

    SciTech Connect

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

    2007-04-01

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

  4. Radiation Hardness Assurance (RHA) for Small Missions

    NASA Technical Reports Server (NTRS)

    Campola, Michael J.

    2016-01-01

    Varied mission life and complexity is growing for small spacecraft. Small missions benefit from detailed hazard definition and evaluation as done in the past. Requirements need to flow from the system down to the parts level and aid system level radiation tolerance. RHA is highlighted with increasing COTS usage.

  5. Radiation hardness of present optical fibres

    NASA Astrophysics Data System (ADS)

    Henschel, Henning

    1994-12-01

    Optical fibers find rapidly growing use also in the nuclear industry. The dependence of their radiation-induced loss on fiber type, wavelength, temperature, light power, dose rate, and radiation type (gamma rays, neutrons) is pointed out and test results of modern (1989 - 1993) single mode (SM), graded index (GI), multimode stepindex (MM SI), and polymer optical fibers (POF) are presented. Continuous 60Co gamma irradiation of the SM fibers with a dose rate of about 1.5 Gy/s up to a final dose of 106 Gy led to radiation-induced losses of only 0.85 to 1.3 dB/10 m at 1300 nm wavelength and temperatures around 30 degree(s)C, whereas the GI fibers had losses of 1.3 to 2 dB/10 m under the same conditions. The lowest radiation-induced loss show MM SI fibers with pure SiO2 core of high OH-content: about 0.15 dB/10 m around 850 nm and about 0.1 dB/10 m around 1060 nm (106 Gy, equals 30 degree(s)C). POF with a core made of polymethyl methacrylate also have loss increases of

  6. Stimulated Ionospheric Scintillations and Absorption of Discreet Cosmic Sources Radiation Investigated with an Imaging HF Riometer

    NASA Astrophysics Data System (ADS)

    Bezrodny, V. G.; Charkina, O. V.; Yampolski, Yu. M.; Watkins, B.; Groves, K.

    2010-06-01

    The effects of enhanced dissipative absorption and increase of scintillation intensity for discreet cosmic sources (DCS) radiation in the polar ionosphere modified by the powerful HF heating have been considered. The investigations have been performed at 38 MHz with the use of the 64-beam riometer located at Alaska in immediate proximity to the HAARP heater. The results of two special heating campaigns of February and October 2008 when the artificially disturbed ionosphere domain was penetrated by the radiation from the two most powerful in the northern sky DCSs, namely Cassiopeia A and Cygnus A, have been discussed. The characteristic features of DCS scintillations induced by natural and artificial inhomogeneities of a Fresnel size in the F-layer of the polar ionosphere have been analyzed. The power spectra of the scintillations have been determined. They allowed recovering the characteristic parameters of the referred inhomogeneities and their motion velocity transverse to the source direction. The additional absorption of DCS radiation and the electron temperature increase in the D-region due to a powerful heater operation are estimated.

  7. Radiation scintillator embedded with a converting medium to detect and discriminate the four species of ionizing radiation

    NASA Astrophysics Data System (ADS)

    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.

  8. A High-Pressure Gas-Scintillation-Proportional Counter for the Focus of a Hard-X-Ray Telescope

    NASA Technical Reports Server (NTRS)

    Austin, R. A.; Ramsey, B. D.; Tse, C. L.

    1999-01-01

    We are developing a high-pressure Gas Scintillation Proportional Counter (GSPC) for the focus of a balloon-borne hard-x-ray telescope. The device has a total active diameter of 50 mm, of which the central 20 mm only is used, and is filled with xenon + 4% helium at a total pressure of 10 6 Pa giving a quantum efficiency of greater than 85% up to 60 keV. The detector entrance is sealed with a beryllium window, 3-mm thick, which provides useful transmission down to 6 keV, way below the atmospheric cut-off at balloon float altitudes. Scintillation light exits the detector via a UV transmitting window in its base and is registered by a Hamamatsu position-sensitive crossed-grid-readout photomultiplier tube. Initial testing is underway, quantifying light yield and energy resolution. Following that, the spatial resolution and absolute efficiency will be calibrated. Simulations show that a spatial resolution of better than 0.5 mm FWHM should be achievable up to 60 keV, and this is well matched to the angular resolution and plate scale of the mirror system. The energy resolution will be around 5% at 22 keV. Full details of the instrument design and its performance will be presented. A first flight is scheduled for the Fall of 99, on a stratospheric balloon to be launched from Fort Sumner, New Mexico.

  9. Scintillators and applications thereof

    DOEpatents

    Williams, Richard T.

    2015-09-01

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

  10. Scintillators and applications thereof

    DOEpatents

    Williams, Richard T.

    2014-07-15

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

  11. Photodiode radiation hardness, lyman-alpha emitting galaxies and photon detection in liquid argon neutrino detectors

    NASA Astrophysics Data System (ADS)

    Baptista, Brian

    2013-12-01

    My dissertation is comprised of three projects: 1) studies of Lyman-alpha Emitting galaxies (LAEs), 2) radiation hardness studies of InGaAs photodiodes (PDs), and 3) scintillation photon detection in liquid argon (LAr) neutrino detectors. I began work on the project that has now become WFIRST, developing a science case that would use WFIRST after launch for the observation of LAEs. The radiation hardness of PDs was as an effort to support the WFIRST calibration team. When WFIRST was significantly delayed, I joined an R&D effort that applied my skills to work on photon detection in LAr neutrino detectors. I report results on a broadband selection method developed to detect high equivalent width (EW) LAEs. Using photometry from the CFHT-Legacy Survey Deep 2 and 3 fields, I have spectroscopically confirmed 63 z=2.5-3.5 LAEs using the WIYN/Hydra spectrograph. Using UV continuum-fitting techniques I computed properties such as EWs, internal reddening and star formation rates. 62 of my LAEs show evidence to be normal dust-free LAEs. Second, I present an investigation into the effects of ionizing proton radiation on commercial off-the-shelf InGaAs PDs. I developed a monochromator-based test apparatus that utilized NIST-calibrated reference PDs. I tested the PDs for changes to their dark current, relative responsivity as a function of wavelength, and absolute responsivity. I irradiated the test PDs using 30, 52, and 98 MeV protons at the IU Cyclotron Facility. I found the InGaAs PDs showed increased dark current as the fluence increased with no evidence of broadband response degradation at the fluences expected at an L2 orbit and a 10-year mission lifetime. Finally, I detail my efforts on technology development of both optical detector technologies and waveshifting light guide construction for LAr vacuum UV scintillation light. Cryogenic neutrino detectors use photon detection for both accelerator based science and for SNe neutrino detection and proton decay. I have

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

    SciTech Connect

    Jing, Tao

    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. Scintillating-nanoparticle-induced enhancement of absorbed radiation dose

    NASA Astrophysics Data System (ADS)

    Withers, Nathan J.; Plumley, John B.; Triño, Nicole D.; Sankar, Krishnaprasad; Akins, Brian A.; Rivera, Antonio C.; Smolyakov, Gennady A.; Timmins, Graham S.; Osinski, Marek

    2009-02-01

    Cerium-doped lanthanum fluoride colloidal nanocrystals offer a way to improve external radiation therapy through the enhanced absorption of high energy photons, as well as through the emission of UV light in the presence of radiation, providing a second cell killing mechanism. Lanthanum fluoride nanocrystals doped with 10% cerium were anhydrously synthesized in methanol as platelets 10-12 nm in diameter and 4-6 nm thick. The nanocrystals were characterized by transmission electron microscopy, energy dispersive spectroscopy (EDS), and by steady state UV-visible optical absorption and photoluminescence spectroscopy. Using an incoming gamma flux from a 137Cs source and a Fricke dosimeter solution to measure absorbed energy, a 55% enhancement of absorbed dose was measured for a 1.2 mg/ml loading of nanocrystals over exposure range from one to four kiloroentgens.

  14. Curve Fitting Solar Cell Degradation Due to Hard Particle Radiation

    NASA Technical Reports Server (NTRS)

    Gaddy, Edward M.; Cikoski, Rebecca; Mekadenaumporn, Danchai

    2003-01-01

    This paper investigates the suitability of the equation for accurately defining solar cell parameter degradation as a function of hard particle radiation. The paper also provides methods for determining the constants in the equation and compares results from this equation to those obtained by the more traditionally used.

  15. Review of radiation hard electronics activities at European Space Agency

    NASA Astrophysics Data System (ADS)

    Furano, G.; Jansen, R.; Menicucci, A.

    2013-02-01

    Several Research and Development activities are ongoing at European Space Agency [1] to secure the supply of key electronic parts for current and future space avionics systems. Analogously to astro-particle and high-energy physics, the space missions radiation environment drives the radiation hardness requirements, which limits availability of suitable electronic components. In particular for the future ESA flagship Jupiter science mission, the necessary processing, reliability, mass, power performance requirements are difficult to meet with current components and systems with sufficient radiation tolerance margins. Improved radiation characterisation and modelling of the Jupiter radiation environment as well as operational radiation monitoring during the mission will be key in ensuring adequate margins for the operation of electronic components.

  16. Radiation resistant composite scintillators based on Al2O3:Ti grains and their properties after irradiation

    NASA Astrophysics Data System (ADS)

    Galunov, N. Z.; Gorbacheva, T. E.; Grinyov, B. V.; Karavaeva, N. L.; Khabuseva, S. U.; Krech, A. V.; Levchuk, L. G.; Litvinov, L. A.; Popov, V. F.; Sorokin, P. V.

    2017-09-01

    The effect of irradiation on the scintillation light output, optical transmittance, and luminescent spectra of composite scintillators based on single crystal grains of Al2O3:Ti, is studied. The dielectric gel Sylgard-184 is the base and the binder for the grains inside the composite scintillator. The paper presents and analyses the results obtained for the scintillators exposed by 10 MeV electrons from the linear electron accelerator at room temperature. For exposure doses at least up to D ∼ 550 Mrad when dose rate is 1500 Mrad/h and D ∼ 125 Mrad when dose rate is 0.2 Mrad/h the composite scintillators are radiation-resistant.

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

    SciTech Connect

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

    2008-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Gopal, Arun

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

  19. Technical Scope of Work: Proton Induced Radiation Damage in Crystal Scintillators

    SciTech Connect

    Zhu, Ren-Yuan; Zhang, Liyuan; Yang, Fan; Ramberg, Eric; Nebel, Todd

    2014-03-11

    This is a technical scope of work (TSW) between the Fermi National Accelerator Laboratory (Fermilab) and the experimenters of California Institute of Technology who have committed to participate in beam tests to be carried out during the 2014 Fermilab Test Beam Facility program. The goal of this investigation is to understand the proton-induced radiation damage in candidate fast crystal scintillators for future HEP experiments. Degradations of the optical and scintillation properties, including emission and transmittance spectra, light output, decay time and light response uniformity, will be measured before and after each step of proton irradiation at Fermilab with a defined fluence. The irradiation will start with a fluence of 1010/cm2 and going up in four steps to 1013/cm2.

  20. Scintillation properties of semiconducting 6LiInSe2 crystals to ionizing radiation

    NASA Astrophysics Data System (ADS)

    Wiggins, Brenden; Groza, Michael; Tupitsyn, Eugene; Lukosi, Eric; Stassun, Keivan; Burger, Arnold; Stowe, Ashley

    2015-11-01

    6LiInSe2 has gained attention recently as a semiconducting thermal neutron detector. As presented herein, the chalcogenide compound semiconductor also detects incident neutrons via scintillation, making 6LiInSe2 the only lithium containing semiconductor to respond to neutrons via both detection mechanisms. Both yellow and red crystals, which appear in the literature, were investigated. Only the yellow crystal responded favorably to ionizing radiation, similar to the semiconducting operation utilizing electrodes. The obtained light yield for yellow crystals is 4400 photons/MeV, referenced to Bi4Ge3O12 (BGO).The estimated thermal neutron light yield was 21,000 photons/thermal neutron. The two measured decay time components were found to be 31±1 ns (49%) and 143±9 ns (51%).This crystal provides efficient, robust detection of neutrons via scintillation with respectable light yield and rapid response, enabling its use for a broad array of neutron detection applications.

  1. Features of Different Inorganic Scintillators Used in Neutron-Radiation Systems for Illegal Substance Detection

    NASA Astrophysics Data System (ADS)

    Batyaev, V. F.; Belichenko, S. G.; Bestaev, R. R.

    2016-04-01

    The work is devoted to a quantitative comparison of different inorganic scintillators to be used in neutron-radiation inspection systems. Such systems can be based on the tagged neutron (TN) method and have a significant potential in different applications such as detection of explosives, drugs, mines, identification of chemical warfare agents, assay of nuclear materials and human body composition [1]-[3]. The elemental composition of an inspected object is determined via spectrometry of gammas from the object bombarded by neutrons which are tagged by an alpha-detector built inside a neutron generator. This creates a task to find a quantitative indicator of the object identification quality (via elemental composition) as a function of basic parameters of the γ-detectors, such as their efficiency, energy and time resolutions, which in turn are generally defined by a scintillator of the detector. We have tried to solve the task for a set of four scintillators which are often used in the study of TN method, namely BGO, LaBr3, LYSO, NaI(Tl), whose basic parameters are well known [4]-[7].

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

    PubMed

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

    2013-01-01

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

  3. Development of a radiation-hard CMOS process

    NASA Technical Reports Server (NTRS)

    Power, W. L.

    1983-01-01

    It is recommended that various techniques be investigated which appear to have the potential for improving the radiation hardness of CMOS devices for prolonged space flight mission. The three key recommended processing techniques are: (1) making the gate oxide thin. It has been shown that radiation degradation is proportional to the cube of oxide thickness so that a relatively small reduction in thickness can greatly improve radiation resistance; (2) cleanliness and contamination control; and (3) to investigate different oxide growth (low temperature dry, TCE and HCL). All three produce high quality clean oxides, which are more radiation tolerant. Technique 2 addresses the reduction of metallic contamination. Technique 3 will produce a higher quality oxide by using slow growth rate conditions, and will minimize the effects of any residual sodium contamination through the introduction of hydrogen and chlorine into the oxide during growth.

  4. Total-dose radiation hardness assurance for space electronics

    SciTech Connect

    Winokur, P.S.; Fleetwood, D.M. )

    1991-01-05

    An improved standard total-dose test method is described to qualify electronics for a low-dose-rate radiation environment typical of space systems. The method consists of {sup 60}Co irradiation at a dose rate of 1--3 Gy(Si)/s (100--300 rad(Si)/s) and a subsequent 373 K (100 {degree}C) bake. New initatives in radiation hardness assurance are also briefly discussed, including the Qualified Manufactures List (QML) test methodology and the possible use of 1/f noise measurements as a nondestructive screen for oxide-trap charge related failure.

  5. Scintillator assembly for alpha radiation detection and an associated method of making

    DOEpatents

    Lauf, Robert J.; McElhaney, Stephanie A.; Bates, John B.

    1994-01-01

    A scintillator assembly for use in conjunction with a photomultiplier or the like in the detection of alpha radiation utilizes a substrate or transparent yttrium aluminum garnet and a relatively thin film of cerium-doped yttrium aluminum garnet coated upon the substrate. The film material is applied to the substrate in a sputtering process, and the applied film and substrate are annealed to effect crystallization of the film upon the substrate. The resultant assembly provides relatively high energy resolution during use in a detection instrument and is sufficiently rugged for use in field environments.

  6. Scintillator assembly for alpha radiation detection and an associated method of making

    DOEpatents

    Lauf, R.J.; McElhaney, S.A.; Bates, J.B.

    1994-07-26

    A scintillator assembly for use in conjunction with a photomultiplier or the like in the detection of alpha radiation utilizes a substrate or transparent yttrium aluminum garnet and a relatively thin film of cerium-doped yttrium aluminum garnet coated upon the substrate. The film material is applied to the substrate in a sputtering process, and the applied film and substrate are annealed to effect crystallization of the film upon the substrate. The resultant assembly provides relatively high energy resolution during use in a detection instrument and is sufficiently rugged for use in field environments. 4 figs.

  7. Growth and Characterization of Nanostructured Glass Ceramic Scintillators for Miniature High-Energy Radiation Sensors

    DTIC Science & Technology

    2013-10-01

    public release; distribution is unlimited. October 2013 HDTRA1-03-D-0009 Mansoor Sheik- Bahae Prepared by: OVPR...Characterization of Nanostructured Glass Ceramic Scintillators for Miniature High-Energy Radiation Sensors HDTRA01-03-D-0009 Mansoor Sheik- Bahae 26 OVPR...Table of Contents…………………………………………………………….3 I . Synthesis of Nano-Structured Glass Ceramic…..……………………………4 II. Characterize Structure and

  8. Solar cell nanotechnology for improved efficiency and radiation hardness

    NASA Astrophysics Data System (ADS)

    Fedoseyev, Alexander I.; Turowski, Marek; Shao, Qinghui; Balandin, Alexander A.

    2006-08-01

    Space electronic equipment, and NASA future exploration missions in particular, require improvements in solar cell efficiency and radiation hardness. Novel nano-engineered materials and quantum-dot array based photovoltaic devices promise to deliver more efficient, lightweight solar cells and arrays which will be of high value to long term space missions. In this paper, we describe issues related to the development of the quantum-dot based solar cells and comprehensive software tools for simulation of the nanostructure-based photovoltaic cells. Some experimental results used for the model validation are also reviewed. The novel modeling and simulation tools for the quantum-dot-based nanostructures help to better understand and predict behavior of the nano-devices and novel materials in space environment, assess technologies, devices, and materials for new electronic systems as well as to better evaluate the performance and radiation response of the devices at an early design stage. The overall objective is to investigate and design new photovoltaic structures based on quantum dots (QDs) with improved efficiency and radiation hardness. The inherently radiation tolerant quantum dots of variable sizes maximize absorption of different light wavelengths, i.e., create a "multicolor" cell, which improves photovoltaic efficiency and diminishes the radiation-induced degradation. The QD models described here are being integrated into the advanced photonic-electronic device simulator NanoTCAD, which can be useful for the optimization of QD superlattices as well as for the development and exploring of new solar cell designs.

  9. Lead carbonate scintillator materials

    DOEpatents

    Derenzo, Stephen E.; Moses, William W.

    1991-01-01

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

  10. Scintillation Counters

    NASA Astrophysics Data System (ADS)

    Bell, Zane W.

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

  11. Radionuclide identification algorithm for organic scintillator-based radiation portal monitor

    NASA Astrophysics Data System (ADS)

    Paff, Marc Gerrit; Di Fulvio, Angela; Clarke, Shaun D.; Pozzi, Sara A.

    2017-03-01

    We have developed an algorithm for on-the-fly radionuclide identification for radiation portal monitors using organic scintillation detectors. The algorithm was demonstrated on experimental data acquired with our pedestrian portal monitor on moving special nuclear material and industrial sources at a purpose-built radiation portal monitor testing facility. The experimental data also included common medical isotopes. The algorithm takes the power spectral density of the cumulative distribution function of the measured pulse height distributions and matches these to reference spectra using a spectral angle mapper. F-score analysis showed that the new algorithm exhibited significant performance improvements over previously implemented radionuclide identification algorithms for organic scintillators. Reliable on-the-fly radionuclide identification would help portal monitor operators more effectively screen out the hundreds of thousands of nuisance alarms they encounter annually due to recent nuclear-medicine patients and cargo containing naturally occurring radioactive material. Portal monitor operators could instead focus on the rare but potentially high impact incidents of nuclear and radiological material smuggling detection for which portal monitors are intended.

  12. Radiation-hard electrical coil and method for its fabrication

    DOEpatents

    Grieggs, R.J.; Blake, R.D.; Gac, F.D.

    1982-06-29

    A radiation-hard insulated electrical coil and method for making the same are disclosed. In accordance with the method, a conductor, preferably copper, is wrapped with an aluminum strip and then tightly wound into a coil. The aluminum-wrapped coil is then annealed to relax the conductor in the coiled configuration. The annealed coil is then immersed in an alkaline solution to dissolve the aluminum strip, leaving the bare conductor in a coiled configuration with all of the windings closely packed yet uniformly spaced from one another. The coil is then insulated with a refractory insulating material. In the preferred embodiment, the coil is insulated by coating it with a vitreous enamel and subsequently potting the enamelled coil in a castable ceramic concrete. The resulting coil is substantially insensitive to radiation and may be operated continuously in high radiation environments for long periods of time.

  13. Radiation hardness of three-dimensional polycrystalline diamond detectors

    SciTech Connect

    Lagomarsino, Stefano Sciortino, Silvio; Bellini, Marco; Corsi, Chiara; Cindro, Vladimir; Kanxheri, Keida; Servoli, Leonello; Morozzi, Arianna; Passeri, Daniele; Schmidt, Christian J.

    2015-05-11

    The three-dimensional concept in particle detection is based on the fabrication of columnar electrodes perpendicular to the surface of a solid state radiation sensor. It permits to improve the radiation resistance characteristics of a material by lowering the necessary bias voltage and shortening the charge carrier path inside the material. If applied to a long-recognized exceptionally radiation-hard material like diamond, this concept promises to pave the way to the realization of detectors of unprecedented performances. We fabricated conventional and three-dimensional polycrystalline diamond detectors, and tested them before and after neutron damage up to 1.2 ×10{sup 16 }cm{sup −2}, 1 MeV-equivalent neutron fluence. We found that the signal collected by the three-dimensional detectors is up to three times higher than that of the conventional planar ones, at the highest neutron damage ever experimented.

  14. A novel fast response and radiation-resistant scintillator detector for beam loss monitor

    NASA Astrophysics Data System (ADS)

    Ji, Y.; Tang, Z.; Li, C.; Li, X.; Shao, M.

    2017-07-01

    At high luminosity area, beam loss monitor with fast response and high radiation resistance is crucial for accelerator operation. In this article, we report the design and test results of a fast response and radiation-resistant scintillator detector as the beam loss monitor for high luminosity collider, especially at low energy region such as RFQ. The detector is consisted of a 2 cm× 2 cm× 0.5 cm LYSO crystal readout by a 6 mm × 6 mm Silicon photomultiplier. Test results from various radioactive sources show that the detector has good sensitivity to photons from tens of keV to several MeV with good linearity and energy resolution (23% for 60 keV γ-ray). For field test, two such detectors are installed outside of the vacuum chamber shell of an 800 MeV electron storage ring. The details of the test and results are introduced.

  15. Laser radiation propagation in the hard and soft dental tissues

    NASA Astrophysics Data System (ADS)

    Dostalova, Tatjana; Jelinkova, Helena; Sulc, Jan; Cerny, Pavel; Nemec, Michal; Cech, Miroslav; Miyagi, Mitsunobu

    2000-03-01

    The objective of this study was to compare the penetration effect of the near and mid-infrared laser radiation. For this reason the Er:YAG, Nd:YAG, and alexandrite laser systems were used in the experiments. The spread of the laser radiation energy in the hard dental tissue surrounding the root canal was evaluated and the possible bactericidal effect of these various laser wavelengths was analyzed. During the measurements, three experimental arrangements were used. The energy transport through the tooth tissue was observed for the frontal and side experimental layout. It was demonstrated that due to the absorption in the hydroxyapatite and water content in the dentin, the Er:YAG laser radiation is fully, and the Nd:YAG is partly absorbed in the root canal's wall. On the other hand, it was proved that the alexandrite laser radiation spreads through the canal system space and leaks into the surrounding tooth tissues. All laser radiation can be efficiently used for killing dental bacteria but the spreading of their radiation in the tooth tissues is different.

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

    NASA Technical Reports Server (NTRS)

    Grindlay, Jonathan E.; Manandhar, Raj P.

    1989-01-01

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

  17. Impact of precursor purity on optical properties and radiation detection of CsI:Tl scintillators

    NASA Astrophysics Data System (ADS)

    Saengkaew, Phannee; Sanorpim, Sakuntam; Jitpukdee, Manit; Cheewajaroen, Kulthawat; Yenchai, Chadet; Thong-aram, Decho; Yordsri, Visittapong; Thanachayanont, Chanchana; Nuntawong, Noppadon

    2016-08-01

    Cesium iodide doped with thallium (CsI:Tl) crystals was grown to develop the gamma-ray detectors by using low-cost raw materials. Effect of impurities on optical properties and radiation detection performance was investigated. By a modified homemade Bridgman-Stockbarger technique, CsI:Tl samples were grown in two levels of CsI and TlI reactant materials, i.e., having as a very high purity of 99.999 % and a high purity of 99.9 %. XRD measurements indicate CsI:Tl crystals having a good quality with a dominant (110) plane. Having a cubic structure, a lattice constant of CsI crystals of 0.4574 nm and a crystallite size of 43.539 nm were obtained. From the lower-purity raw materials, calcite was found in an orange crystal with a lattice constant of 0.4560 nm and a crystallite size of 43.089 nm. By PL measurements, the optical properties of the CsI:Tl crystals were analyzed. ~540-nm-wavelength PL peak was observed from the colorless high-purity crystal, and ~600-nm-wavelength PL peak was observed from the orange crystal. The brighter PL emission was obtained from the orange crystals suggesting impurities. CsI:Tl surface morphology by SEM exhibited a smooth surface with some parallel crystal facets. For electrical properties of high-quality CsI:Tl crystals, the electrical resistances were 230 ± 16 MΩ in cross-sectional direction and 714 ± 136 MΩ in vertical direction with respect to more homogeneous crystal quality in cross-sectional direction than that in vertical direction. TEM measurement was applied to evaluate the microstructure of colorless CsI:Tl crystal with different patterns of a cubic structure. Both CsI:Tl crystals show good efficiencies and good resolutions. Maintaining the same electronic conditions and amplifications, the colorless CsI:Tl scintillators represented a higher detection efficiency at 122 keV of Co-57 of 78.4 % and the energy resolution of 23.3 % compared to the detection efficiency of 75.9 % and the energy resolution of 34.6 % of the orange

  18. Radiation Hardness Assurance (RHA): Challenges and New Considerations

    NASA Technical Reports Server (NTRS)

    Campola, Michael J.

    2017-01-01

    Radiation Hardness Assurance (RHA) challenges associated with the use of commercial-off-the-shelf (COTS) components and emerging technologies are cause for risk acceptance in space flight missions. The RHA flow includes environment definition, hazard evaluation, requirements definition, evaluation of design, and design trades to accommodate the risk a project or program takes. The varied missions profiles and environments don't necessarily benefit from the same risk reduction efforts or cost reduction attempts. The level of effort within the RHA flow can be tailored to minimize risk based on the environment or design criticality.

  19. Radiation-hard/high-speed parallel optical links

    NASA Astrophysics Data System (ADS)

    Gan, K. K.; Buchholz, P.; Heidbrink, S.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Vogt, M.; Ziolkowski, M.

    2016-09-01

    We have designed and fabricated a compact parallel optical engine for transmitting data at 5 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The performance of the optical engine up at 5 Gb/s is satisfactory.

  20. Absorption of infrared radiation by human dental hard substances

    NASA Astrophysics Data System (ADS)

    Roth, Klaus K.; Duczynski, Edwin W.; von der Heide, Hans-Joachim; Struve, Bert

    1993-12-01

    Absorption spectra of enamel, dentin, synthetic hydroxyapatite and deionized water were taken in the wavelength band 500 to 3000 nm. It could be shown that infrared radiation is mainly absorbed in the aqueous components of dental hard tissues. Because of their decreased water content extinctions measured are slightly lower than those of deionized water. Furthermore, mineral absorptions could be detected in the range of 2760 to 2840 nm with a maximum at 2800 nm in enamel and a smaller one at 2500 nm in dentin.

  1. WE-AB-BRB-03: Real-Time Volumetric Scintillation Dosimetry for Radiation Therapy.

    PubMed

    Beddar, S

    2016-06-01

    Despite widespread IMRT treatments at modern radiation therapy clinics, precise dosimetric commissioning of an IMRT system remains a challenge. In the most recent report from the Radiological Physics Center (RPC), nearly 20% of institutions failed an end-to-end test with an anthropomorphic head and neck phantom, a test that has rather lenient dose difference and distance-to-agreement criteria of 7% and 4 mm. The RPC report provides strong evidence that IMRT implementation is prone to error and that improved quality assurance tools are required. At the heart of radiation therapy dosimetry is the multidimensional dosimeter. However, due to the limited availability of water-equivalent dosimetry materials, research and development in this important field is challenging. In this session, we will review a few dosimeter developments that are either in the laboratory phase or in the pre-commercialization phase. 1) Radiochromic plastic. Novel formulations exhibit light absorbing optical contrast with very little scatter, enabling faster, broad beam optical CT design. 2) Storage phosphor. After irradiation, the dosimetry panels will be read out using a dedicated 2D scanning apparatus in a non-invasive, electro-optic manner and immediately restored for further use. 3) Liquid scintillator. Scintillators convert the energy from x-rays and proton beams into visible light, which can be recorded with a scientific camera (CCD or CMOS) from multiple angles. The 3D shape of the dose distribution can then be reconstructed. 4) Cherenkov emission imaging. Gated intensified imaging allows video-rate passive detection of Cherenkov emission during radiation therapy with the room lights on.

  2. Toward 3D dosimetry of intensity modulated radiation therapy treatments with plastic scintillation detectors

    NASA Astrophysics Data System (ADS)

    Guillot, M.; Gingras, L.; Archambault, L.; Beddar, S.; Beaulieu, L.

    2010-11-01

    In this work, we present a novel two Dimensional Plastic Scintillation Detector (2D-PSD) array designed to measure dose distributions generated by high energy photon beams from medical linear accelerators. This study aim to demonstrate that the dose distribution in the irradiated volume is not modified by the presence of several hundred plastic scintillation detectors (PSDs). The 2D-PSD consists of 781 PSDs inserted in a plastic water slab. The dose distributions measured with the 2D-PSD were compared to calculations from a treatment planning system (Pinnacle3, Philips Medical Systems) and with measurements taken with an ionization chambers array (MatriXX Evolution, IBA Dosimetry). Furthermore, a clinical head and neck IMRT plan was delivered on the 2D-PSD. A good agreement is obtained between the measured and planned dose distributions. The results show that the 2D arrangement presented in this work is water equivalent and transparent to x-ray radiation. As a consequence, our design could be extended to multiple detection planes, opening the possibility for 3D dosimetry with PSDs.

  3. SIFTER: Scintillating Fiber Telescopes for Energetic Radiation, Gamma-Ray Applications

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.

    2002-01-01

    The research project "SIFTER: Scintillating Fiber Telescopes for Energetic Radiation, Gamma-Ray Applications" approved under the NASA High Energy Astrophysics Research Program. The principal investigator of the proposal was Prof. Geoffrey N. Pendleton, who is currently on extended leave from UAH. Prof. William S. Paciesas administered the grant during Dr. Pendleton's absence. The project was originally funded for one year from 6/8/2000 to 6/7/2001. Due to conflicts with other commitments by the PI, the period of performance was extended at no additional cost until 6/30/2002. The goal of this project was to study scintillating fiber pair-tracking gamma-ray telescope configurations specifically designed to perform imaging and spectroscopy in the 5 - 250 MeV energy range. The main efforts were concentrated in two areas: 1) development of tracking techniques and event reconstruction algorithms, with particular emphasis on angular resolution; and 2) investigation of coded apertures as a means to improve the instrument angular resolution at low energies.

  4. Liquid scintillator tiles for calorimetry

    DOE PAGES

    Amouzegar, M.; Belloni, A.; Bilki, B.; ...

    2016-11-28

    Future experiments in high energy and nuclear physics may require large, inexpensive calorimeters that can continue to operate after receiving doses of 50 Mrad or more. Also, the light output of liquid scintillators suffers little degradation under irradiation. However, many challenges exist before liquids can be used in sampling calorimetry, especially regarding developing a packaging that has sufficient efficiency and uniformity of light collection, as well as suitable mechanical properties. We present the results of a study of a scintillator tile based on the EJ-309 liquid scintillator using cosmic rays and test beam on the light collection efficiency and uniformity,more » and some preliminary results on radiation hardness.« less

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  6. Validated Models for Radiation Response and Signal Generation in Scintillators: Final Report

    SciTech Connect

    Kerisit, Sebastien N.; Gao, Fei; Xie, YuLong; Campbell, Luke W.; Van Ginhoven, Renee M.; Wang, Zhiguo; Prange, Micah P.; Wu, Dangxin

    2014-12-01

    This Final Report presents work carried out at Pacific Northwest National Laboratory (PNNL) under the project entitled “Validated Models for Radiation Response and Signal Generation in Scintillators” (Project number: PL10-Scin-theor-PD2Jf) and led by Drs. Fei Gao and Sebastien N. Kerisit. This project was divided into four tasks: 1) Electronic response functions (ab initio data model) 2) Electron-hole yield, variance, and spatial distribution 3) Ab initio calculations of information carrier properties 4) Transport of electron-hole pairs and scintillation efficiency Detailed information on the results obtained in each of the four tasks is provided in this Final Report. Furthermore, published peer-reviewed articles based on the work carried under this project are included in Appendix. This work was supported by the National Nuclear Security Administration, Office of Nuclear Nonproliferation Research and Development (DNN R&D/NA-22), of the U.S. Department of Energy (DOE).

  7. Scintillator assembly for alpha radiation detection and method of making the assembly

    DOEpatents

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

    1992-09-22

    A scintillator assembly for use in the detection of alpha radiation includes a body of optically-transparent epoxy and an amount of phosphor particles embedded within the body adjacent one surface thereof. When making the body, the phosphor particles are mixed with the epoxy when in an uncured condition and permitted to settle to the bottom surface of a mold within which the epoxy/phosphor mixture is contained. When the mixture subsequently cures to form a hardened body, the one surface of the body which cured against the bottom surface of the mold is coated with a thin layer of opaque material for preventing ambient light form entering the body through the one surface. The layer of opaque material is thereafter coated with a layer of protective material to provide the assembly with a damage-resistant entrance window. 6 figs.

  8. Scintillator assembly for alpha radiation detection and method of making the assembly

    DOEpatents

    McElhaney, Stephanie A.; Bauer, Martin L.; Chiles, Marion M.

    1992-01-01

    A scintillator assembly for use in the detection of alpha radiation includes a body of optically-transparent epoxy and an amount of phosphor particles embedded within the body adjacent one surface thereof. When making the body, the phosphor particles are mixed with the epoxy when in an uncured condition and permitted to settle to the bottom surface of a mold within which the epoxy/phosphor mixture is contained. When the mixture subsequently cures to form a hardened body, the one surface of the body which cured against the bottom surface of the mold is coated with a thin layer of opaque material for preventing ambient light form entering the body through the one surface. The layer of opaque material is thereafter coated with a layer of protective material to provide the assembly with a damage-resistant entrance window.

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

    SciTech Connect

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

    2005-07-15

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

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

    PubMed

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

    2005-07-01

    Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter. © 2005 American Association of Physicists in Medicine.

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

    PubMed

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

    2005-07-01

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

  12. Crystal growth and characterization of europium doped lithium strontium iodide scintillator as an ionizing radiation detector

    NASA Astrophysics Data System (ADS)

    Uba, Samuel

    High performance detectors used in the detection of ionizing radiation is critical to nuclear nonproliferation applications and other radiation detectors applications. In this research we grew and tested Europium doped Lithium Strontium Iodide compound. A mixture of lithium iodide, strontium iodide and europium iodide was used as the starting materials for this research. Congruent melting and freezing temperature of the synthesized compound was determined by differential scanning calorimetry (DSC) using a Setaram Labsys Evo DSC-DTA instrument. The melting temperatures were recorded at 390.35°C, 407.59°C and freezing temperature was recorded at 322.84°C from a graph of heat flow plotted against temperature. The synthesized material was used as the charge for the vertical Bridgeman growth, and a 6.5 cm and 7.7cm length boule were grown in a multi-zone transparent Mullen furnace. A scintillating detector of thickness 2.53mm was fabricated by mechanical lapping in mineral oil, and scintillating response and timing were obtained to a cesium source using CS-137 isotope. An energy resolution (FWHM over peak position) of 12.1% was observed for the 662keV full absorption peak. Optical absorption in the UV-Vis wavelength range was recorded for the grown crystal using a U-2900 UV/VIS Spectrophotometer. Absorption peaks were recorded at 194nm, 273nm, and 344nm from the absorbance spectrum, various optical parameters such as absorption coefficient, extinction coefficient, refractive index, and optical loss were derived. The optical band gap energy was calculated using Tauc relation expression at 1.79eV.

  13. Strategies for Radiation Hardness Testing of Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Soltis, James V. (Technical Monitor); Patton, Martin O.; Harris, Richard D.; Rohal, Robert G.; Blue, Thomas E.; Kauffman, Andrew C.; Frasca, Albert J.

    2005-01-01

    Plans on the drawing board for future space missions call for much larger power systems than have been flown in the past. These systems would employ much higher voltages and currents to enable more powerful electric propulsion engines and other improvements on what will also be much larger spacecraft. Long term human outposts on the moon and planets would also require high voltage, high current and long life power sources. Only hundreds of watts are produced and controlled on a typical robotic exploration spacecraft today. Megawatt systems are required for tomorrow. Semiconductor devices used to control and convert electrical energy in large space power systems will be exposed to electromagnetic and particle radiation of many types, depending on the trajectory and duration of the mission and on the power source. It is necessary to understand the often very different effects of the radiations on the control and conversion systems. Power semiconductor test strategies that we have developed and employed will be presented, along with selected results. The early results that we have obtained in testing large power semiconductor devices give a good indication of the degradation in electrical performance that can be expected in response to a given dose. We are also able to highlight differences in radiation hardness that may be device or material specific.

  14. Radiation Hardness Assurance (RHA): Challenges and New Considerations

    NASA Technical Reports Server (NTRS)

    Campola, Michael J.

    2017-01-01

    Use of commercial-off-the-shelf (COTS) components and emerging technologies often require space flight missions to accept elevated risk. The Radiation Hardness Assurance (RHA) flow includes environment definition, hazard evaluation, requirements definition, evaluation of design, and design trades to accommodate and mitigate the risk a project or program takes. Depending on the mission profile and environment, different missions may not necessarily benefit from the same risk reduction efforts or cost reduction attempts. While this poses challenges for the radiation engineer, it also presents opportunities to tailor the RHA flow to minimize risk based on the environment or design criticality while remaining within budget. This presentation will focus on an approach to RHA amidst the present challenges, using the same RHA flow as in the past, with examples from recent radiation test results. The current challenges and the types of risk will be identified. How these risks drive requirements development and realization will be explained with examples of device results and data for single event effects (SEE) and in one case total ionizing dose (TID).

  15. Radiation hardness of the storage phosphor europium doped potassium chloride for radiation therapy dosimetry

    SciTech Connect

    Driewer, Joseph P.; Chen, Haijian; Osvet, Andres; Low, Daniel A.; Li, H. Harold

    2011-08-15

    Purpose: An important property of a reusable dosimeter is its radiation hardness, that is, its ability to retain its dosimetric merits after irradiation. The radiation hardness of europium doped potassium chloride (KCl:Eu{sup 2+}), a storage phosphor material recently proposed for radiation therapy dosimetry, is examined in this study. Methods: Pellet-style KCl:Eu{sup 2+} dosimeters, 6 mm in diameter, and 1 mm thick, were fabricated in-house for this study. The pellets were exposed by a 6 MV photon beam or in a high dose rate {sup 137}Cs irradiator. Macroscopic properties, such as radiation sensitivity, dose response linearity, and signal stability, were studied with a laboratory photostimulated luminescence (PSL) readout system. Since phosphor performance is related to the state of the storage centers and the activator, Eu{sup 2+}, in the host lattice, spectroscopic and temporal measurements were carried out in order to explore radiation-induced changes at the microscopic level. Results: KCl:Eu{sup 2+} dosimeters retained approximately 90% of their initial signal strength after a 5000 Gy dose history. Dose response was initially supralinear over the dose range of 100-700 cGy but became linear after 60 Gy. Linearity did not change significantly in the 0-5000 Gy dose history spanned in this study. Annealing high dose history chips resulted in a return of supralinearity and a recovery of sensitivity. There were no significant changes in the PSL stimulation spectra, PSL emission spectra, photoluminescence spectra, or luminescence lifetime, indicating that the PSL signal process remains intact after irradiation but at a reduced efficiency due to reparable radiation-induced perturbations in the crystal lattice. Conclusions: Systematic studies of KCl:Eu{sup 2+} material are important for understanding how the material can be optimized for radiation therapy dosimetry purposes. The data presented here indicate that KCl:Eu{sup 2+} exhibits strong radiation hardness and

  16. Experimental study of hard photon radiation processes at HERA

    NASA Astrophysics Data System (ADS)

    Ahmed, T.; Aid, S.; Andreev, V.; Andrieu, B.; Appuhn, R.-D.; Arpagaus, M.; Babaev, A.; Baehr, J.; Bán, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Barth, M.; Bassler, U.; Beck, H. P.; Behrend, H.-J.; Belousov, A.; Berger, Ch.; Bergstein, H.; Bernardi, G.; Bernet, R.; Bertrand-Coremans, G.; Besançon, M.; Beyer, R.; Biddulph, P.; Bizot, J. C.; Blobel, V.; Borras, K.; Botterweck, F.; Boudry, V.; Braemer, A.; Brasse, F.; Braunschweig, W.; Brisson, V.; Bruncko, D.; Brune, C.; Buchholz, R.; Büngener, L.; Bürger, J.; Büsser, F. W.; Buniatian, A.; Burke, S.; Buschhorn, G.; Campbell, A. J.; Carli, T.; Charles, F.; Clarke, D.; Clegg, A. B.; Clerbaux, B.; Colombo, M.; Contreras, J. G.; Cormack, C.; Coughlan, J. A.; Courau, A.; Coutures, Ch.; Cozzika, G.; Criegee, L.; Cussans, D. G.; Cvach, J.; Dagoret, S.; Dainton, J. B.; Danilov, M.; Dau, W. D.; Daum, K.; David, M.; Deffur, E.; Delcourt, B.; Del Buono, L.; de Roeck, A.; de Wolf, E. A.; di Nezza, P.; Dollfus, C.; Dowell, J. D.; Dreis, H. B.; Droutskoi, A.; Duboc, J.; Düllmann, D.; Dünger, O.; Duhm, H.; Ebert, J.; Ebert, T. R.; Eckerlin, G.; Efremenko, V.; Egli, S.; Ehrlichmann, H.; Eichenberger, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellison, R. J.; Elsen, E.; Erdmann, M.; Erdmann, W.; Evrard, E.; Favart, L.; Fedotov, A.; Feeken, D.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrarotto, F.; Flamm, K.; Fleischer, M.; Flieser, M.; Flügge, G.; Fomenko, A.; Fominykh, B.; Forbush, M.; Formánek, J.; Foster, J. M.; Franke, G.; Fretwurst, E.; Gabathuler, E.; Gabathuler, K.; Gamerdinger, K.; Garvey, J.; Gayler, J.; Gebauer, M.; Gellrich, A.; Genzel, H.; Gerhards, R.; Goerlach, U.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goldner, D.; Gonzalez-Pineiro, B.; Gorelov, I.; Goritchev, P.; Grab, C.; Grässler, H.; Grässler, R.; Greenshaw, T.; Grindhammer, G.; Gruber, A.; Gruber, C.; Haack, J.; Haidt, D.; Hajduk, L.; Hamon, O.; Hampel, M.; Hanlon, E. M.; Hapke, M.; Haynes, W. J.; Heatherington, J.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herma, R.; Herynek, I.; Hess, M. F.; Hildesheim, W.; Hill, P.; Hiller, K. H.; Hilton, C. D.; Hladký, J.; Hoeger, K. C.; Höppner, M.; Horisberger, R.; Hudgson, V. L.; Huet, Ph.; Hütte, M.; Hufnagel, H.; Ibbotson, M.; Itterbeck, H.; Jabiol, M.-A.; Jacholkowska, A.; Jacobsson, C.; Jaffre, M.; Janoth, J.; Jansen, T.; Jönsson, L.; Johannsen, K.; Johnson, D. P.; Johnson, L.; Jung, H.; Kalmus, P. I. P.; Kant, D.; Kaschowitz, R.; Kasselmann, P.; Kathage, U.; Katzy, J.; Kaufmann, H. H.; Kazarian, S.; Kenyon, I. R.; Kermiche, S.; Keuker, C.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Ko, W.; Köhler, T.; Köhne, J.; Kolanoski, H.; Kole, F.; Kolya, S. D.; Korbel, V.; Korn, M.; Kostka, P.; Kotelnikov, S. K.; Krämerkämper, T.; Krasny, M. W.; Krehbiel, H.; Krücker, D.; Krüger, U.; Krüner-Marquis, U.; Kubenka, J. P.; Küster, H.; Kuhlen, M.; Kurča, T.; Kurzhöfer, J.; Kuznik, B.; Lacour, D.; Lamarche, F.; Lander, R.; Landon, M. P. J.; Lange, W.; Lanius, P.; Laporte, J.-F.; Lebedev, A.; Leverenz, C.; Levonian, S.; Ley, Ch.; Lindner, A.; Lindström, G.; Linsel, F.; Lipinski, J.; List, B.; Loch, P.; Lohmander, H.; Lopez, G. C.; Lubimov, V.; Lüke, D.; Magnussen, N.; Malinovski, E.; Mani, S.; Maraček, R.; Marage, P.; Marks, J.; Marshall, R.; Martens, J.; Martin, R.; Martyn, H.-U.; Martyniak, J.; Masson, S.; Mavroidis, T.; Maxfield, S. J.; McMahon, S. J.; Mehta, A.; Meier, K.; Mercer, D.; Merz, T.; Meyer, C. A.; Meyer, H.; Meyer, J.; Mikocki, S.; Milstead, D.; Moreau, F.; Morris, J. V.; Mroczko, E.; Müller, G.; Müller, K.; Murín, P.; Nagovizin, V.; Nahnhauer, R.; Naroska, B.; Naumann, Th.; Newman, P. R.; Newton, D.; Neyret, D.; Nguyen, H. K.; Nicholls, T. C.; Niebergall, F.; Niebuhr, C.; Nisius, R.; Nowak, G.; Noyes, G. W.; Nyberg-Werther, M.; Oakden, M.; Oberlack, H.; Obrock, U.; Olsson, J. E.; Ozerov, D.; Panaro, E.; Panitch, A.; Pascaud, C.; Patel, G. D.; Peppel, E.; Perez, E.; Phillips, J. P.; Pichler, Ch.; Pitzl, D.; Pope, G.; Prell, S.; Prosi, R.; Rädel, G.; Raupach, F.; Reimer, P.; Reinshagen, S.; Ribarics, P.; Rick, H.; Riech, V.; Riedlberger, J.; Riess, S.; Rietz, M.; Rizvi, E.; Robertson, S. M.; Robmann, P.; Roloff, H. E.; Roosen, R.; Rosenbauer, K.; Rostovtsev, A.; Rouse, F.; Royon, C.; Rüter, K.; Rusakov, S.; Rybicki, K.; Rylko, R.; Sahlmann, N.; Sanchez, E.; Sankey, D. P. C.; Savitsky, M.; Schacht, P.; Schiek, S.; Schleper, P.; von Schlippe, W.; Schmidt, C.; Schmidt, D.; Schmidt, G.; Schöning, A.; Schröder, V.; Schuhmann, E.; Schwab, B.; Schwind, A.; Seehausen, U.; Sefkow, F.; Seidel, M.; Sell, R.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shooshtari, H.; Shtarkov, L. N.; Siegmon, G.; Siewert, U.; Sirois, Y.; Skillicorn, I. O.; Smirnov, P.; Smith, J. R.; Solochenko, V.; Soloviev, Y.; Spiekermann, J.; Spitzer, H.; Starosta, R.; Steenbock, M.; Steffen, P.; Steinberg, R.; Stella, B.; Stephens, K.; Stier, J.; Stiewe, J.; Stösslein, U.; Stolze, K.; Strachota, J.; Straumann, U.; Struczinski, W.; Sutton, J. P.; Tapprogge, S.; Taylor, R. E.; Tchernyshov, V.; Thiebaux, C.; Thompson, G.; Truöl, P.; Turnau, J.; Tutas, J.; Uelkes, P.; Usik, A.; Valkár, S.; Valkárová, A.; Vallée, C.; van Esch, P.; van Mechelen, P.; Vartapetian, A.; Vazdik, Y.; Vecko, M.; Verrecchia, P.; Villet, G.; Wacker, K.; Wagener, A.; Wagener, M.; Walker, I. W.; Walther, A.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wellisch, H. P.; West, L. R.; Willard, S.; Winde, M.; Winter, G.-G.; Wright, A. E.; Wünsch, E.; Wulff, N.; Yiou, T. P.; Žáček, J.; Zarbock, D.; Zhang, Z.; Zhokin, A.; Zimmer, M.; Zimmermann, W.; Zomer, F.; Zuber, K.

    1995-12-01

    We present an experimental study of the ep→ eγ+ p and ep→ eγ+ X processes using data recorded by the H1 detector in 1993 at the electron-proton collider HERA. These processes are employed to measure the luminosity with an accuracy of 4.5 %. A subsample of the ep→ eγ+ X events in which the hard photon is detected at angles θ{γ/'} ≤ 0.45 mrad with respect to the incident electron direction is used to verify experimentally the size of radiative corrections to the ep→ eX inclusive cross section and to investigate the structure of the proton in the Q 2 domain down to 2 GeV2, lower than previously attained at HERA.

  17. Radiation-hard/high-speed array-based optical engine

    NASA Astrophysics Data System (ADS)

    Gan, K. K.; Buchholz, P.; Heidbrink, S.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Vogt, M.; Ziolkowski, M.

    2016-12-01

    We have designed and fabricated a compact array-based optical engine for transmitting data at 10 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The DAC settings are stored in SEU (single event upset) tolerant registers. Several devices were irradiated with 24 GeV/c protons and the performance of the devices is satisfactory after the irradiation.

  18. Verification of intensity modulated radiation therapy beams using a tissue equivalent plastic scintillator dosimetry system

    NASA Astrophysics Data System (ADS)

    Petric, Martin Peter

    This thesis describes the development and implementation of a novel method for the dosimetric verification of intensity modulated radiation therapy (IMRT) fields with several advantages over current techniques. Through the use of a tissue equivalent plastic scintillator sheet viewed by a charge-coupled device (CCD) camera, this method provides a truly tissue equivalent dosimetry system capable of efficiently and accurately performing field-by-field verification of IMRT plans. This work was motivated by an initial study comparing two IMRT treatment planning systems. The clinical functionality of BrainLAB's BrainSCAN and Varian's Helios IMRT treatment planning systems were compared in terms of implementation and commissioning, dose optimization, and plan assessment. Implementation and commissioning revealed differences in the beam data required to characterize the beam prior to use with the BrainSCAN system requiring higher resolution data compared to Helios. This difference was found to impact on the ability of the systems to accurately calculate dose for highly modulated fields, with BrainSCAN being more successful than Helios. The dose optimization and plan assessment comparisons revealed that while both systems use considerably different optimization algorithms and user-control interfaces, they are both capable of producing substantially equivalent dose plans. The extensive use of dosimetric verification techniques in the IMRT treatment planning comparison study motivated the development and implementation of a novel IMRT dosimetric verification system. The system consists of a water-filled phantom with a tissue equivalent plastic scintillator sheet built into the top surface. Scintillation light is reflected by a plastic mirror within the phantom towards a viewing window where it is captured using a CCD camera. Optical photon spread is removed using a micro-louvre optical collimator and by deconvolving a glare kernel from the raw images. Characterization of this

  19. The response of a radiation resistant ceramic scintillator (Al{sub 2}O{sub 3}:Cr) to low energy ions (0-60 keV)

    SciTech Connect

    Jimenez-Rey, D.; Zurro, B.; McCarthy, K. J.; Baciero, A.; Garcia, G.

    2008-10-15

    This work extends a previous study on ionoluminescence of a radiation-hard ceramic scintillator, Al{sub 2}O{sub 3}:Cr, to ions accelerated to keV energies [K. J. McCarthy et al., J. Nucl. Mater. 321, 78 (2003)]. It is motivated by the identification of this material as a promising candidate for use in the fast-ion-loss detector for ITER [for the range of thermal (low energy) and suprathermal ions]. In the paper we quantify and compare its ionoluminescence with that of some common luminescent materials (YAG:Ce and ruby) when irradiated by H{sup +} ions accelerated to {<=}60 keV using a purpose built laboratory setup. Next, studies are made on the ceramic to quantify its response as a function of incident ion mass, i.e., to He{sup +}. For this, the absolute luminosities of the material are estimated in terms of the number of photons emitted per incident ion as a function of energy. Moreover, the radiation hardness and postirradiation recovery of the ceramic are investigated. Finally, from the studies it can be concluded that the ceramic ruby is a good candidate for detecting low energy ions as long as its temporal response (approximately several milliseconds) is not a constraint for specific ion measurements.

  20. Notional Radiation Hardness Assurance (RHA) Planning For NASA Missions: Updated Guidance

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Pellish, Jonathan A.

    2014-01-01

    Radiation Hardness Assurance (RHA) is the process of ensuring space system performance in the presence of a space radiation environment. Herein, we present an updated NASA methodology for RHA focusing on content, deliverables and timeframes.

  1. National Radiation Hardness Assurance (RHA) Planning For NASA Missions: Updated Guidance

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Pellish, Jonathan Allen

    2014-01-01

    Radiation Hardness Assurance (RHA) is the process of ensuring space system performance in the presence of a space radiation environment. Herein, we present an updated NASA methodology for RHA focusing on content, deliverables and timeframes.

  2. Performance prospects for the CMS electromagnetic calorimeter barrel avalanche photodiodes for LHC phase I and phase II: Radiation hardness and longevity

    NASA Astrophysics Data System (ADS)

    Addesa, F.; Cavallari, F.

    2015-07-01

    The electromagnetic calorimeter of the Compact Muon Solenoid (CMS) experiment at the LHC is a hermetic, fine-grained, homogeneous calorimeter, comprising 75,848 lead tungstate scintillating crystals. Avalanche photodiodes produced by Hamamatsu are used as sensors for the electromagnetic barrel calorimeter. These devices were tested for radiation hardness assuming an integrated luminosity of 500 fb-1, which corresponds to a neutron fluence of 2- 4 ×1013 n /cm2, depending on the detector location. Beginning in 2022, a new phase of the LHC is foreseen to exploit the full potential of the accelerator, which will deliver 3000 fb-1 of integrated luminosity. Irradiation studies up to a fluence of 1.5 ×1014 n /cm2 have been performed to qualify the avalanche photodiodes for radiation hardness. We present measurements of gain, quantum efficiency and noise, and discuss the implications for the CMS electromagnetic barrel calorimeter performance.

  3. Lead carbonate scintillator materials

    DOEpatents

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

    1991-05-14

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

  4. Stimulated recovery of the optical transmission of PbWO 4 scintillation crystals for electromagnetic calorimeters after radiation damage

    NASA Astrophysics Data System (ADS)

    Dormenev, V.; Kuske, T.; Novotny, R. W.; Borisevich, A.; Fedorov, A.; Korjik, M.; Mechinski, V.; Missevitch, O.; Lugert, S.

    2010-11-01

    In this paper we describe the phenomenon of the stimulated recovery of radiation damage in lead tungstate scintillation crystals achieved via illumination by visible and infrared light. It allows fast and efficient in-situ recovery of the optical transmission either during beam-off periods or on-line during data accumulation. The application can substantially improve or extend the running period of the experiment by keeping the damage at a tolerable level.

  5. Photon statistics in scintillation crystals

    NASA Astrophysics Data System (ADS)

    Bora, Vaibhav Joga Singh

    Scintillation based gamma-ray detectors are widely used in medical imaging, high-energy physics, astronomy and national security. Scintillation gamma-ray detectors are eld-tested, relatively inexpensive, and have good detection eciency. Semi-conductor detectors are gaining popularity because of their superior capability to resolve gamma-ray energies. However, they are relatively hard to manufacture and therefore, at this time, not available in as large formats and much more expensive than scintillation gamma-ray detectors. Scintillation gamma-ray detectors consist of: a scintillator, a material that emits optical (scintillation) photons when it interacts with ionization radiation, and an optical detector that detects the emitted scintillation photons and converts them into an electrical signal. Compared to semiconductor gamma-ray detectors, scintillation gamma-ray detectors have relatively poor capability to resolve gamma-ray energies. This is in large part attributed to the "statistical limit" on the number of scintillation photons. The origin of this statistical limit is the assumption that scintillation photons are either Poisson distributed or super-Poisson distributed. This statistical limit is often dened by the Fano factor. The Fano factor of an integer-valued random process is dened as the ratio of its variance to its mean. Therefore, a Poisson process has a Fano factor of one. The classical theory of light limits the Fano factor of the number of photons to a value greater than or equal to one (Poisson case). However, the quantum theory of light allows for Fano factors to be less than one. We used two methods to look at the correlations between two detectors looking at same scintillation pulse to estimate the Fano factor of the scintillation photons. The relationship between the Fano factor and the correlation between the integral of the two signals detected was analytically derived, and the Fano factor was estimated using the measurements for SrI2:Eu, YAP

  6. Development and characterization of new scintillation materials for fiber tracking and calorimetry

    NASA Astrophysics Data System (ADS)

    Bross, A. D.; Pla-Dalmau, A.; Baumbaugh, B.; Godfrey, J.; Jaques, J.; Marchant, J.; Piekarz, J.; Ruchti, R.

    1991-09-01

    Several polystyrene-based scintillators have been prepared in the Chemistry Facility of Fermi National Accelerator Laboratory and their light yield, fluorescence, and transmittance have been studied. In addition, emission time distributions were measured and the decay time constants were determined. A radiation damage study was performed in which the samples were irradiated to a total dose of 10 Mrad. After annealing, the intrinsic light yield of the most radiation-hard scintillators had not changed significantly.

  7. Fault tolerant, radiation hard, high performance digital signal processor

    NASA Technical Reports Server (NTRS)

    Holmann, Edgar; Linscott, Ivan R.; Maurer, Michael J.; Tyler, G. L.; Libby, Vibeke

    1990-01-01

    An architecture has been developed for a high-performance VLSI digital signal processor that is highly reliable, fault-tolerant, and radiation-hard. The signal processor, part of a spacecraft receiver designed to support uplink radio science experiments at the outer planets, organizes the connections between redundant arithmetic resources, register files, and memory through a shuffle exchange communication network. The configuration of the network and the state of the processor resources are all under microprogram control, which both maps the resources according to algorithmic needs and reconfigures the processing should a failure occur. In addition, the microprogram is reloadable through the uplink to accommodate changes in the science objectives throughout the course of the mission. The processor will be implemented with silicon compiler tools, and its design will be verified through silicon compilation simulation at all levels from the resources to full functionality. By blending reconfiguration with redundancy the processor implementation is fault-tolerant and reliable, and possesses the long expected lifetime needed for a spacecraft mission to the outer planets.

  8. Development of high temperature, radiation hard detectors based on diamond

    NASA Astrophysics Data System (ADS)

    Metcalfe, Alex; Fern, George R.; Hobson, Peter R.; Ireland, Terry; Salimian, Ali; Silver, Jack; Smith, David R.; Lefeuvre, Gwenaelle; Saenger, Richard

    2017-02-01

    Single crystal CVD diamond has many desirable properties compared to current, well developed, detector materials; exceptional radiation, chemical and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry), wide bandgap and an intrinsic pathway to fast neutron detection through the 12C(n,α)9Be reaction. However effective exploitation of these properties requires development of a suitable metallisation scheme to give stable contacts for high temperature applications. To best utilise available processing techniques to optimise sensor response through geometry and conversion media configurations, a reliable model is required. This must assess the performance in terms of spectral response and overall efficiency as a function of detector and converter geometry. The same is also required for proper interpretation of experimental data. Sensors have been fabricated with varying metallisation schemes indented to permit high temperature operation; Present test results indicate that viable fabrication schemes for high temperature contacts have been developed and present modelling results, supported by preliminary data from partners indicate simulations provide a useful representation of response.

  9. BGO as a hybrid scintillator / Cherenkov radiator for cost-effective time-of-flight PET

    NASA Astrophysics Data System (ADS)

    Brunner, S. E.; Schaart, D. R.

    2017-06-01

    Due to detector developments in the last decade, the time-of-flight (TOF) method is now commonly used to improve the quality of positron emission tomography (PET) images. Clinical TOF-PET systems based on L(Y)SO:Ce crystals and silicon photomultipliers (SiPMs) with coincidence resolving times (CRT) between 325 ps and 400 ps FWHM have recently been developed. Before the introduction of L(Y)SO:Ce, BGO was used in many PET systems. In addition to a lower price, BGO offers a superior attenuation coefficient and a higher photoelectric fraction than L(Y)SO:Ce. However, BGO is generally considered an inferior TOF-PET scintillator. In recent years, TOF-PET detectors based on the Cherenkov effect have been proposed. However, the low Cherenkov photon yield in the order of  ˜10 photons per event complicates energy discrimination-a severe disadvantage in clinical PET. The optical characteristics of BGO, in particular its high transparency down to 310 nm and its high refractive index of  ˜2.15, are expected to make it a good Cherenkov radiator. Here, we study the feasibility of combining event timing based on Cherenkov emission with energy discrimination based on scintillation in BGO, as a potential approach towards a cost-effective TOF-PET detector. Rise time measurements were performed using a time-correlated single photon counting (TCSPC) setup implemented on a digital photon counter (DPC) array, revealing a prompt luminescent component likely to be due to Cherenkov emission. Coincidence timing measurements were performed using BGO crystals with a cross-section of 3 mm  ×  3 mm and five different lengths between 3 mm and 20 mm, coupled to DPC arrays. Non-Gaussian coincidence spectra with a FWHM of 200 ps were obtained with the 27 mm3 BGO cubes, while FWHM values as good as 330 ps were achieved with the 20 mm long crystals. The FWHM value was found to improve with decreasing temperature, while the FWTM value showed the opposite trend.

  10. BGO as a hybrid scintillator / Cherenkov radiator for cost-effective time-of-flight PET.

    PubMed

    Brunner, Stefan E; Schaart, Dennis

    2017-03-30

    Due to detector developments in the last decade, the time-of-flight (TOF) method is now commonly used to improve the quality of positron emission tomography (PET) images. Clinical TOF-PET systems based on L(Y)SO:Ce crystals and silicon photomultipliers (SiPMs) with coincidence resolving times (CRT) between 325 ps and 400 ps FWHM have recently been developed. Before the introduction of L(Y)SO:Ce, BGO was used in many PET systems. In addition to a lower price, BGO offers a superior attenuation coefficient and a higher photoelectric fraction than L(Y)SO:Ce. However, BGO is generally considered an inferior TOF-PET scintillator. In recent years, TOF-PET detectors based on the Cherenkov effect have been proposed. However, the low Cherenkov photon yield in the order of ∽10 photons per event complicates energy discrimination-a severe disadvantage in clinical PET. The optical characteristics of BGO, in particular its high transparency down to 310 nm and its high refractive index of ∽2.15, are expected to make it a good Cherenkov radiator. Here, we study the feasibility of combining event timing based on Cherenkov emission with energy discrimination based on scintillation in BGO, as a potential approach towards a cost-effective TOF-PET detector. Rise time measurements were performed using a time-correlated single photon counting (TCSPC) setup implemented on a digital photon counter (DPC) array, revealing a prompt luminescent component likely to be due to Cherenkov emission. Coincidence timing measurements were performed using BGO crystals with a cross-section of 3 mm × 3 mm and five different lengths between 3 mm and 20 mm, coupled to DPC arrays. Non-Gaussian coincidence spectra with a FWHM of 200 ps were obtained with the 27 mm3 BGO cubes, while FWHM values as good as 330 ps were achieved with the 20 mm long crystals. The FWHM value was found to improve with decreasing temperature, while the FWTM value showed the opposite trend.

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

    NASA Astrophysics Data System (ADS)

    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

  12. Silica scintillating materials prepared by sol-gel methods

    SciTech Connect

    Werst, D.W.; Sauer, M.C. Jr.; Cromack, K.R.; Lin, Y.; Tartakovsky, E.A.; Trifunac, A.D.

    1993-12-31

    Silica was investigated as a rad-hard alternative to organic polymer hosts for organic scintillators. Silica sol-gels were prepared by hydrolysis of tetramethoxysilane in alcohol solutions. organic dyes were incorporated into the gels by dissolving in methanol at the sol stage of gel formation. The silica sol-gel matrix is very rad-hard. The radiation stability of silica scintillators prepared by this method is dye-limited. Transient radioluminescence was measured following excitation with 30 ps pulses of 20 MeV electrons.

  13. Study of the response of a lithium yttrium borate scintillator based neutron rem counter by Monte Carlo radiation transport simulations

    NASA Astrophysics Data System (ADS)

    Sunil, C.; Tyagi, Mohit; Biju, K.; Shanbhag, A. A.; Bandyopadhyay, T.

    2015-12-01

    The scarcity and the high cost of 3He has spurred the use of various detectors for neutron monitoring. A new lithium yttrium borate scintillator developed in BARC has been studied for its use in a neutron rem counter. The scintillator is made of natural lithium and boron, and the yield of reaction products that will generate a signal in a real time detector has been studied by FLUKA Monte Carlo radiation transport code. A 2 cm lead introduced to enhance the gamma rejection shows no appreciable change in the shape of the fluence response or in the yield of reaction products. The fluence response when normalized at the average energy of an Am-Be neutron source shows promise of being used as rem counter.

  14. Optical transmission damage of undoped and Ce doped Y3Al5O12 scintillation crystals under 24 GeV protons high fluence

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Fedorov, A.; Dormenev, V.; Houžvička, J.; Korjik, M.; Lucchini, M. T.; Mechinsky, V.; Ochesanu, S.

    2017-06-01

    This report presents results on the optical transmission damage of undoped and Ce doped Y3Al5O12 scintillation crystals under high fluence of 24 GeV protons. We observed that, similarly to other middle heavy scintillators, it possesses the unique radiation hardness at fluence values as high as 5×1014 p/cm2 and it is thus promising for the application in the detectors at High Luminosity LHC. The crystalline structure of the garnet scintillator allows to control and further optimize its scintillation parameters, such as scintillation decay time and emission wavelength, and shows a limited set of the radioisotopes after the irradiation with protons.

  15. New Cerium-Based Metal-Organic Scintillators for Radiation Detection

    SciTech Connect

    Boatner, Lynn A; Neal, John S; Ramey, Joanne Oxendine; Chakoumakos, Bryan C; Custelcean, Radu; Van Loef, Edgar; Markosyan, G

    2013-01-01

    We have previously shown that a new class of scintillating materials can be developed based on the synthesis and crystal growth of rare-earth metal-organic compounds. The first scintillator of this type consisted of single crystals of CeCl3(CH3OH)4 that were grown from a methanol solution. These crystals were shown to be applicable to both gamma-ray and fast neutron detection. Subsequently, metal-organic scintillators consisting of the compound LaBr3(CH3OH)4 activated with varying levels of Ce3+ and of CeBr3(CH3OH)4 were grown in single crystal form. We have now extended the development of this new class of scintillators to more complex organic components by reacting rare-earth halides such as CeCl3 or CeBr3 with different isomers of propanol and butanol including 1-propanol, isobutanol, n-butanol, and tert-butanol. The reaction of CeCl3 or CeBr3 with these organics results in the formation of new and relatively complex molecular crystals whose structures were determined using single-crystal X-ray diffraction. These new metal-organic scintillating materials were grown in single crystal form from solution, and their scintillation characteristics have been investigated using X-ray-excited luminescence plus energy spectra obtained with gamma-ray and alpha-particle sources. If the reactions between the inorganic and organic components are not carried out under very dry and highly controlled conditions, molecular structures can be formed that incorporate waters of hydration. The present observation of scintillation in these hydrated rare-earth metal-organic compounds is apparently an original finding, since we are not aware of any previous reports of scintillation being observed in a material that incorporates waters of hydration

  16. High fluence neutron radiation of plastic scintillators for the TileCal of the ATLAS detector.

    NASA Astrophysics Data System (ADS)

    Mdhluli, J. E.; Davydov, Yu I.; Baranov, V.; Mthembu, S.; Erasmus, R.; Jivan, H.; Khanye, N.; Tlou, H.; Tjale, B.; Starchenko, J.; Solovyanov, O.; Mellado, B.; Sideras-Haddad, E.

    2017-09-01

    We report on structural and optical properties of neutron irradiated plastic scintillators. These scintillators were subjected to a neutron beam with wide energy range of up to 10MeV and a neutron flux range of 1.2 × 1012 – 9.4 × 1012 n/cm 2 using the IBR-2 pulsed reactor at the Joint Institute for Nuclear Research in Dubna. A study between polyvinyl toluene based commercial scintillators EJ200, EJ208 and EJ260 as well as polystyrene based scintillator from Kharkov is conducted. Light transmission, Raman spectroscopy, fluorescence spectroscopy and light yield testing was performed to characterize the damage induced in the samples. Preliminary results from the tests performed indicate no change in the optical and structural properties of the scintillators. The polystyrene based scintillators were further subjected to a higher neutron flux range of 3.8 × 1012 – 1.8 × 1014 n/cm 2 using the IBR-2 pulsed reactor.

  17. SCINTILLATION SPECTROMETER

    DOEpatents

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

    1960-06-21

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

  18. Effect of gamma radiation on micromechanical hardness of lead-free solder joint

    SciTech Connect

    Paulus, Wilfred; Rahman, Irman Abdul; Jalar, Azman; Kamil, Insan; Bakar, Maria Abu; Yusoff, Wan Yusmawati Wan

    2015-09-25

    Lead-free solders are important material in nano and microelectronic surface mounting technology for various applications in bio medicine, environmental monitoring, spacecraft and satellite instrumentation. Nevertheless solder joint in radiation environment needs higher reliability and resistance to any damage caused by ionizing radiations. In this study a lead-free 99.0Sn0.3Ag0.7Cu wt.% (SAC) solder joint was developed and subjected to various doses of gamma radiation to investigate the effects of the ionizing radiation to micromechanical hardness of the solder. Averaged hardness of the SAC joint was obtained from nanoindentation test. The results show a relationship between hardness values of indentations and the increment of radiation dose. Highest mean hardness, 0.2290 ± 0.0270 GPa was calculated on solder joint which was exposed to 5 Gray dose of gamma radiation. This value indicates possible radiation hardening effect on irradiated solder. The hardness gradually decreased to 0.1933 ± 0.0210 GPa and 0.1631 ± 0.0173 GPa when exposed to doses 50 and 500 gray respectively. These values are also lower than the hardness of non irradiated sample which was calculated as 0.2084 ± 0.0.3633 GPa indicating possible radiation damage and needs further related atomic dislocation study.

  19. The comparison of radiation hardness of heterojunction SiGe and conventional silicon bipolar transistors

    NASA Astrophysics Data System (ADS)

    Bakerenkov, A. S.; Felitsyn, V. A.; Rodin, A. S.

    2016-10-01

    The results of the X-ray radiation impact on heterojunction SiGe and conventional silicon bipolar transistors are presented. Oxide thickness over the emitter-base junction depletion region determines the radiation hardness of the bipolar transistors. In this article, the estimation of the rate of radiation degradation of electrical parameters for conventional silicon devices and SiGe-transistors is performed.

  20. Effects of He radiation on cavity distribution and hardness of bulk nanolayered Cu-Nb composites

    NASA Astrophysics Data System (ADS)

    Yang, L. X.; Zheng, S. J.; Zhou, Y. T.; Zhang, J.; Wang, Y. Q.; Jiang, C. B.; Mara, N. A.; Beyerlein, I. J.; Ma, X. L.

    2017-04-01

    Interface engineering is an important strategy for developing radiation tolerant materials. In prior work, bulk nanolayered composites fabricated by accumulative roll bonding (ARB) showed outstanding radiation resistance. However, the effects of layer thickness and radiation conditions on damage distributions and their effect on hardness have not been explored. Here, we use transmission electron microscopy (TEM) and nanoindentation to investigate the effects of radiation on the distribution of radiation-induced cavities and post-radiation hardness in ARB nanolayered Cu-Nb composites. We show that whether the cavities cross the interface depends on layer thickness and temperature, and that, remarkably, radiation could generate softening, not always hardening. We posit that the softening mainly results from the recovery of dislocations stored in the crystal after the bulk forming ARB processing due to He radiation and this phenomenon offsets radiation-induced hardening as layers become finer and temperatures rise.

  1. A confident source of hard X-rays: radiation from a tokamak applicable for runaway electrons diagnosis.

    PubMed

    Kafi, M; Salar Elahi, A; Ghoranneviss, M; Ghanbari, M R; Salem, M K

    2016-09-01

    In a tokamak with a toroidal electric field, electrons that exceed the critical velocity are freely accelerated and can reach very high energies. These so-called `runaway electrons' can cause severe damage to the vacuum vessel and are a dangerous source of hard X-rays. Here the effect of toroidal electric and magnetic field changes on the characteristics of runaway electrons is reported. A possible technique for runaways diagnosis is the detection of hard X-ray radiation; for this purpose, a scintillator (NaI) was used. Because of the high loop voltage at the beginning of a plasma, this investigation was carried out on toroidal electric field changes in the first 5 ms interval from the beginning of the plasma. In addition, the toroidal magnetic field was monitored for the whole discharge time. The results indicate that with increasing toroidal electric field the mean energy of runaway electrons rises, and also an increase in the toroidal magnetic field can result in a decrease in intensity of magnetohydrodynamic oscillations which means that for both conditions more of these high-energy electrons will be generated.

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  3. Current trends in scintillator detectors and materials

    SciTech Connect

    Moses, William W.

    2001-10-23

    The last decade has seen a renaissance in inorganic scintillator development for gamma ray detection. Lead tungstate (PbWO4) has been developed for high energy physics experiments, and possesses exceptionally high density and radiation hardness, albeit with low luminous efficiency. Lutetium orthosilicate or LSO (Lu2SiO5:Ce) possesses a unique combination of high luminous efficiency, high density, and reasonably short decay time, and is now incorporated in commercial positron emission tomography (PET) cameras. There have been advances in understanding the fundamental mechanisms that limit energy resolution, and several recently discovered materials (such as LaBr3:Ce) possess energy resolution that approaches that of direct solid state detectors. Finally, there are indications that a neglected class of scintillator materials that exhibit near band-edge fluorescence could provide scintillators with sub-nanosecond decay times and high luminescent efficiency.

  4. The Use of Hard Synchrotron Radiation for Diffraction Studies of Composite and Functional Materials

    NASA Astrophysics Data System (ADS)

    Ancharov, A. I.

    2017-07-01

    Potential use of hard synchrotron radiation (SR) with the quantum energy above 25 keV is discussed aiming to solve a number of research tasks on investigation of structural changes taking place in materials. The advantages and limitations of the use of hard SR for diffraction studies are evaluated. A review of the principal techniques is made wherein application of hard SR both promotes certain experimental investigations and frequently allows obtaining new structural data unavailable with X-ray tubes.

  5. Model-Based Assurance Case+ (MBAC+): Tutorial on Modeling Radiation Hardness Assurance Activities

    NASA Technical Reports Server (NTRS)

    Austin, Rebekah; Label, Ken A.; Sampson, Mike J.; Evans, John; Witulski, Art; Sierawski, Brian; Karsai, Gabor; Mahadevan, Nag; Schrimpf, Ron; Reed, Robert A.

    2017-01-01

    This presentation will cover why modeling is useful for radiation hardness assurance cases, and also provide information on Model-Based Assurance Case+ (MBAC+), NASAs Reliability Maintainability Template, and Fault Propagation Modeling.

  6. A novel radiation detector consisting of an H /SUB g/ I/sub 2/ photo detector coupled to a scintillator

    SciTech Connect

    Iwanczyk, J.S.; Barton, J.B.; Dabrowski, A.J.; Kusmiss, J.H.; Szymczyk, W.M.

    1983-02-01

    HgI/sub 2/ photodetectors have been used in conjunction with CsI(T1) and BGO to detect the light pulses from gamma rays and alpha particles. The photocurrent response to light of a typical H /SUB g/ I/sub 2/ photodetector is presented and discussed. The spectral response is appropriate for most important scintillators, which have their maximum emission between 400 and 560 nm. Energy spectra obtained with an HgI/sub 2/ photodetector coupled to a CsI(T1) scintillator crystal are presented for gamma rays from /sup 137/Cs, a /sup 68/Ga positron source, /sup 241/Am, and /SUP 99m/ Tc, as well as for the K x-rays from Pb. The photopeak energy resolution value for 511 keV annihilation gamma rays with the CsI(T1)-HgI/sub 2/ combination was about 10%. Spectra obtained with an HgI/sub 2/ photodetector coupled to a BGO scintillator crystal are presented for the annihilation gamma rays from a /sup 68/Ga positron source (19% photopeak resolution) and the alpha particles from a /sup 244/Cm source. Estimates of the quantum efficiencies for an HgI/sub 2/ photodetector coupled to CsI(T1) and BGO scintillator crystals give values in excess of 70%. A brief discussion is given of the limits on energy resolution set by the electronic noise. Potential applications of this novel radiation detection device and the advantages over photomultiplier-based devices are discussed.

  7. Influence of design variables on radiation hardness of silicon MINP solar cells

    NASA Technical Reports Server (NTRS)

    Anderson, W. A.; Solaun, S.; Rao, B. B.; Banerjee, S.

    1985-01-01

    Metal-insulator-N/P silicon (MINP) solar cells were fabricated using different substrate resistivity values, different N-layer designs, and different I-layer designs. A shallow junction into an 0.3 ohm-cm substrate gave best efficiency whereas a deeper junction into a 1 to 4 ohm-cm substrate gave improved radiation hardness. I-layer design variation did little to influence radiation hardness.

  8. Comparison of the radiation hardness of various VLSI technologies for defense applications

    SciTech Connect

    Gibbon, C.F.

    1985-01-01

    In this review the radiation hardness of various potential very large scale (VLSI) IC technologies is evaluated. IC scaling produces several countervailing trends. Reducing vertical dimensions tends to increase total dose hardness, while reducing lateral feature sizes may increase susceptibility to transient radiation effects. It is concluded that during the next decade at least, silicon complimentary MOS (CMOS), perhaps on an insulating substrate (SOI) will be the technology of choice for VLSI in defense systems.

  9. System and plastic scintillator for discrimination of thermal neutron, fast neutron, and gamma radiation

    DOEpatents

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

    2017-05-16

    A scintillator material according to one embodiment includes a polymer matrix; a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount of 3 wt % or more; and at least one component in the polymer matrix, the component being selected from a group consisting of B, Li, Gd, a B-containing compound, a Li-containing compound and a Gd-containing compound, wherein the scintillator material exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays. A system according to one embodiment includes a scintillator material as disclosed herein and a photodetector for detecting the response of the material to fast neutron, thermal neutron and gamma ray irradiation.

  10. Improving the radiation hardness of graphene field effect transistors

    DOE PAGES

    Alexandrou, Konstantinos; Masurkar, Amrita; Edrees, Hassan; ...

    2016-10-11

    Ionizing radiation poses a significant challenge to the operation and reliability of conventional silicon-based devices. In this paper, we report the effects of gamma radiation on graphene field-effect transistors (GFETs), along with a method to mitigate those effects by developing a radiation-hardened version of our back-gated GFETs. We demonstrate that activated atmospheric oxygen from the gamma ray interaction with air damages the semiconductor device, and damage to the substrate contributes additional threshold voltage instability. Our radiation-hardened devices, which have protection against these two effects, exhibit minimal performance degradation, improved stability, and significantly reduced hysteresis after prolonged gamma radiation exposure. Finally,more » we believe this work provides an insight into graphene's interactions with ionizing radiation that could enable future graphene-based electronic devices to be used for space, military, and other radiation-sensitive applications.« less

  11. Improving the radiation hardness of graphene field effect transistors

    SciTech Connect

    Alexandrou, Konstantinos; Masurkar, Amrita; Edrees, Hassan; Wishart, James F.; Hao, Yufeng; Petrone, Nicholas; Hone, James; Kymissis, Ioannis

    2016-10-11

    Ionizing radiation poses a significant challenge to the operation and reliability of conventional silicon-based devices. In this paper, we report the effects of gamma radiation on graphene field-effect transistors (GFETs), along with a method to mitigate those effects by developing a radiation-hardened version of our back-gated GFETs. We demonstrate that activated atmospheric oxygen from the gamma ray interaction with air damages the semiconductor device, and damage to the substrate contributes additional threshold voltage instability. Our radiation-hardened devices, which have protection against these two effects, exhibit minimal performance degradation, improved stability, and significantly reduced hysteresis after prolonged gamma radiation exposure. Finally, we believe this work provides an insight into graphene's interactions with ionizing radiation that could enable future graphene-based electronic devices to be used for space, military, and other radiation-sensitive applications.

  12. Improving the radiation hardness of graphene field effect transistors

    NASA Astrophysics Data System (ADS)

    Alexandrou, Konstantinos; Masurkar, Amrita; Edrees, Hassan; Wishart, James F.; Hao, Yufeng; Petrone, Nicholas; Hone, James; Kymissis, Ioannis

    2016-10-01

    Ionizing radiation poses a significant challenge to the operation and reliability of conventional silicon-based devices. Here, we report the effects of gamma radiation on graphene field-effect transistors (GFETs), along with a method to mitigate those effects by developing a radiation-hardened version of our back-gated GFETs. We demonstrate that activated atmospheric oxygen from the gamma ray interaction with air damages the semiconductor device, and damage to the substrate contributes additional threshold voltage instability. Our radiation-hardened devices, which have protection against these two effects, exhibit minimal performance degradation, improved stability, and significantly reduced hysteresis after prolonged gamma radiation exposure. We believe this work provides an insight into graphene's interactions with ionizing radiation that could enable future graphene-based electronic devices to be used for space, military, and other radiation-sensitive applications.

  13. Influence of radiation damage on the performance of a lead/scintillator calorimeter investigated with 1-6 GeV electrons

    NASA Astrophysics Data System (ADS)

    Bohnet, I.; Kummerow, D.; Wick, K.

    2002-09-01

    The influence of radiation damage on energy resolution, linearity and uniformity of an electromagnetic lead/scintillator calorimeter was studied experimentally with 1-6 GeV electrons. Plastic scintillators and wavelength shifter bars were irradiated uniformly with γ rays. Both were identical with those of the ZEUS uranium calorimeter. The attenuation length of the scintillators was determined from bench tests of single scintillator tiles and from beam tests of the whole calorimeter. After exposure to a dose of 10 kGy the attenuation length of the scintillators decreased by a factor of 2. The experimental results show that the irradiation of the nearly 2 m long wavelength shifter bars affects the calorimeter much more than the damage of the scintillators which were only 19 cm long. Damaged and undamaged sections of the calorimeter were scanned with a moving radioactive γ source ( 60Co). The results demonstrate that the 60Co monitor system is a very precise tool to detect radiation damage in a sampling calorimeter.

  14. Effect Of Clock Mode On Radiation Hardness Of An ADC

    NASA Technical Reports Server (NTRS)

    Lee, Choon I.; Rax, Bernie G.; Johnston, Allan H.

    1995-01-01

    Report discusses techniques for testing and evaluating effects of total dosages of ionizing radiation on performances of high-resolution successive-approximation analog-to-digital converters (ADCs), without having to test each individual bit or transition. Reduces cost of testing by reducing tests to few critical parametric measurements, from which one determines approximate radiation failure levels providing good approximations of responses of converters for purpose of total-dose-radiation evaluations.

  15. Radiation Detection and Classification of Heavy Oxide Inorganic Scintillator Crystals for Detection of Fast Neutrons

    DTIC Science & Technology

    2016-06-01

    and alkali -halide scintillators for potential use in neutron and gamma detection systems.” M.S. thesis, Dept. Physics, Naval Posgraduate School...assets.newport.com/webDocuments- EN/images/2151_And_2153_User_Manual_RevC.pdf Accessed Apr. 1, 2016. [25] Metal package PMT with cooler photosensor modules

  16. Gaseous photomultipliers for the readout of scintillators and detection Cherenkov radiation

    SciTech Connect

    Peskov, V.; Borovik-Romanov, A.

    1993-11-01

    The latest achievements in the development of gaseous detectors for registering UV and visible photons are described. Possible modifications of their design for some particular applications such as the readout of crystal scintillators. noble liquids, fibers and for large area Cherenkov detectors are discussed.

  17. Transition radiation in metal-metal multilayer nanostructures as a medical source of hard x-ray radiation

    SciTech Connect

    Pokrovsky, A. L.; Kaplan, A. E.; Shkolnikov, P. L.

    2006-08-15

    We show that a periodic metal-metal multilayer nanostructure can serve as an efficient source of hard x-ray transition radiation. Our research effort is aimed at developing an x-ray source for medical applications, which is based on using low-energy relativistic electrons. The approach toward choosing radiator-spacer couples for the generation of hard x-ray resonant transition radiation by few-MeV electrons traversing solid multilayer structures for the energies of interest to medicine (30-50 keV) changes dramatically compared with that for soft x-ray radiation. We show that one of the main factors in achieving the required resonant line is the absence of the contrast of the refractive indices between the spacer and the radiator at the far wings of the radiation line; for that purpose, the optimal spacer, as a rule, should have a higher atomic number than the radiator. Having experimental goals in mind, we have considered also the unwanted effects due to bremsstrahlung radiation, absorption and scattering of radiated photons, detector-related issues, and inhibited coherence of transition radiation due to random deviation of spacing between the layers. Choosing as a model example a Mo-Ag radiator-spacer pair of materials, we demonstrate that the x-ray transition radiation line can be well resolved with the use of spatial and frequency filtering.

  18. Outward atmospheric scintillation effects and inward atmospheric scintillation effects comparisons for direct detection ladar applications

    NASA Astrophysics Data System (ADS)

    Youmans, Douglas G.

    2014-06-01

    Atmospheric turbulence produces intensity modulation or "scintillation" effects on both on the outward laser-mode path and on the return backscattered radiation path. These both degrade laser radar (ladar) target acquisition, ranging, imaging, and feature estimation. However, the finite sized objects create scintillation averaging on the outgoing path and the finite sized telescope apertures produce scintillation averaging on the return path. We expand on previous papers going to moderate to strong turbulence cases by starting from a 20kft altitude platform and propagating at 0° elevation (with respect to the local vertical) for 100km range to a 1 m diameter diffuse sphere. The outward scintillation and inward scintillation effects, as measured at the focal plane detector array of the receiving aperture, will be compared. To eliminate hard-body surface speckle effects in order to study scintillation, Goodman's M-parameter is set to 106 in the analytical equations and the non-coherent imaging algorithm is employed in Monte Carlo realizations. The analytical equations of the signal-to-noise ratio (SNRp), or mean squared signal over a variance, for a given focal plane array pixel window of interest will be summarized and compared to Monte Carlo realizations of a 1m diffuse sphere.

  19. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology.

    PubMed

    Xapsos, M A; Stauffer, C; Phan, A; McClure, S S; Ladbury, R L; Pellish, J A; Campola, M J; LaBel, K A

    2017-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission.

  20. Radiation hardness improvement of analog front-end microelectronic devices for particle accelerator

    NASA Astrophysics Data System (ADS)

    Miroshnichenko, A. G.; Rodin, A. S.; Bakerenkov, A. S.; Felitsyn, V. A.

    2016-10-01

    Series of schematic techniques for increasing radiation hardness of the current mirrors is developed. These techniques can be used for the design of analog front-end microelectronic devices based on the operational amplifiers. The circuit simulation of radiation degradation of current transmission coefficients was performed for various circuit solutions in LTSpice software.

  1. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology

    NASA Technical Reports Server (NTRS)

    Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; LaBel, K. A.

    2016-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission.

  2. Radiation hardness by design for mixed signal infrared readout circuit applications

    NASA Astrophysics Data System (ADS)

    Gaalema, Stephen; Gates, James; Dobyns, David; Pauls, Greg; Wall, Bruce

    2013-09-01

    Readout integrated circuits (ROICs) to support space-based infrared detection applications often have severe radiation tolerance requirements. Radiation hardness-by-design (RHBD) significantly enhances the radiation tolerance of commercially available CMOS and custom radiation hardened fabrication techniques are not required. The combination of application specific design techniques, enclosed gate architecture nFETs and intrinsic thin oxide radiation hardness of 180 nm process node commercial CMOS allows realization of high performance mixed signal circuits. Black Forest Engineering has used RHBD techniques to develop ROICs with integrated A/D conversion that operate over a wide range of temperatures (40K-300K) to support infrared detection. ROIC radiation tolerance capability for 256x256 LWIR area arrays and 1x128 thermopile linear arrays is presented. The use of 130 nm CMOS for future ROIC RHBD applications is discussed.

  3. SU-E-T-167: Characterization of In-House Plastic Scintillator Detectors Array for Radiation Therapy

    SciTech Connect

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

    2015-06-15

    Purpose: To characterize basic performance of plastic scintillator detectors (PSD) array designed for dosimetry of radiation therapy. Methods: An in-house PSD array has been developed by placing single point PSD into customized 2D holder. Each point PSD is a plastic scintillating fiber-based detector designed for highly accurate measurement of small radiotherapy fields used in patient plan verification and machine commissioning and QA procedures. A parallel fiber without PSD is used for Cerenkov separation by subtracting from PSD readings. Cerenkov separation was confirmed by optical spectroscopy. Alternative Cerenkov separation approaches are also investigated. The optical signal was converted to electronic signal with a photodiode and then subsequently amplified. We measured its dosimetry performance, including percentage depth dose and output factor, and compared with reference ion chamber measurements. The PSD array is then placed along the radiation beam for multiple point dose measurement, representing subsets of PDD measurements, or perpendicular to the beam for profile measurements. Results: The dosimetry results of PSD point measurements agree well with reference ion chamber measurements. For percentage depth dose, the maximal differences between PSD and ion chamber results are 3.5% and 2.7% for 6MV and 15MV beams, respectively. For the output factors, PSD measurements are within 3% from ion chamber results. PDD and profile measurement with PSD array are also performed. Conclusions: The current design of multichannel PSD array is feasible for the dosimetry measurement in radiation therapy. Dose distribution along or perpendicular to the beam path could be measured. It might as well be used as range verification in proton therapy.A PS hollow fiber detector will be investigated to eliminate the Cerenkov radiation effect so that all 32 channels can be used.

  4. Design and development of a hard tube flexible radiator system

    NASA Technical Reports Server (NTRS)

    Hixon, C. W.

    1980-01-01

    The construction and operational characteristics of an extended life flexible radiator panel is described. The radiator panel consists of a flexible fin laminate and stainless steel flow tubes designed for a 90 percent probability of surviving 5 years in an Earth orbit micrometeoroid environment. The radiator panel rejects 1.1 kW sub t of heat into an environmental sink temperature of 0 F. Total area is 170 square feet and the panel extends 25 feet in the fully deployed position. When retracted the panel rolls onto a 11.5 inch diameter by 52 inch long storage drum, for a final stored diameter of 22 inches.

  5. Gamma-ray radiation response at 1550 nm of fluorine-doped radiation hard single-mode optical fiber.

    PubMed

    Kim, Youngwoong; Ju, Seongmin; Jeong, Seongmook; Lee, Seung Ho; Han, Won-Taek

    2016-02-22

    We have investigated gamma-ray radiation response at 1550 nm of fluorine-doped radiation hard single-mode optical fiber. Radiation-induced attenuation (RIA) of the optical fiber was measured under intermittent gamma-ray irradiations with dose rate of ~10 kGy/h. No radiation hardening effect on the RIA by the gamma-ray pre-dose was found when the exposed fiber was bleached for long periods of time (27~47 days) at room-temperature. Photo-bleaching scheme upon 980 nm LD pumping has proven to be an effective deterrent to the RIA, particularly by suppressing the incipient RIA due to room-temperature unstable self-trapped hole defects (STHs). Large temperature dependence of the RIA of the optical fiber together with the photo-bleaching effect are worthy of note for reinforcing its radiation hard characteristics.

  6. Interplanetary phase scintillation and the search for very low frequency gravitational radiation

    NASA Technical Reports Server (NTRS)

    Armstrong, J. W.; Woo, R.; Estabrook, F. B.

    1979-01-01

    Observations of radio-wave phase scintillation are reported which used the Viking spacecraft having an earth-spacecraft link very similar to that which will be used in very low-frequency (VLF) gravitational-wave searches. The phase power-spectrum level varies by seven orders of magnitude as the sun-earth-spacecraft (elongation) angle changes from 1 to 175 deg. It is noteworthy that a broad minimum in the S-band (2.3 GHz) phase fluctuation occurs in the antisolar direction; the corresponding fractional frequency stability (square root Allan variance) is about 3 x 10 to the -14th for 1000-s integration times. A simultaneous two-frequency two-station observation indicates that the contribution to the phase fluctuation from the ionosphere is significant but dominated by the contribution from the interplanetary medium. Nondispersive tropospheric scintillation was not detected (upper limit to fractional frequency stability about 5 x 10 to the -14th). Evidently, even observations in the antisolar direction will require higher radio frequencies, phase scintillation calibration, and correlation techniques in the data processing, for detection of gravitational bursts at the anticipated strain amplitude levels of no more than 10 to the -15th.

  7. Radiation-hard breadboard star tracker. Final report

    SciTech Connect

    Hubbard, M.W.; Murata, D.L.

    1985-09-01

    Operation in a radiation environment affects the performance of many types of electro-optical sensors. Specifically, noise generated from radiation in the detector and front-end electronics in star trackers can degrade the performance of the sensors. Upsets in the related processing electronics can cause loss of track, data interruptions, and in some cases, failure to recover. Degradation of performance can occur in a natural charged-particle environment and becomes worse in a weapon-enhanced radiation environment. High total dose results in component and, in turn, system failure to operate. The objectives of this program, which was conducted by Ball Aerospace Systems Division (BASD) for the Naval Research Laboratory (NRL), were to develop a tracker that could survive a high total dose and to gain a better understanding of the transient effects of radiation on the star tracker performance. Survivability of the star tracker in a radiation environment, both at the component level and at the system level, is of primary importance.

  8. Radiation hardness of Efratom M-100 rubidium frequency standard

    NASA Technical Reports Server (NTRS)

    English, T. C.; Vorwerk, H.; Rudie, N. J.

    1983-01-01

    The effects of nuclear radiation on rubidium gas cell frequency standards and components are presented, including the results of recent tests where a continuously operating rubidium frequency standard (Effratom, Model M-100) was subjected to simultaneous neutron/gamma radiation. At the highest neutron fluence 7.5 10 to the 12th power n/sq cm and total dose 11 krad(Si) tested, the unit operated satisfactorily; the total frequency change over the 2 1/2 hour test period due to all causes, including repeated retraction from and insertion into the reactor, was less than 1 x 10 to the -10th power. The effects of combined neutron/gamma radiation on rubidium frequency standard physics package components were also studied, and the results are presented.

  9. Radiation hardness of Efratom M-100 rubidium frequency standard

    SciTech Connect

    English, T.C.; Vorwerk, H.; Rudie, N.J.

    1983-02-01

    The effects of nuclear radiation on rubidium gas cell frequency standards and components are presented, including the results of recent tests where a continuously operating rubidium frequency standard (Effratom, Model M-100) was subjected to simultaneous neutron/gamma radiation. At the highest neutron fluence 7.5 10 to the 12th power n/sq cm and total dose 11 krad(Si) tested, the unit operated satisfactorily. The total frequency change over the 2 1/2 hour test period due to all causes, including repeated retraction from and insertion into the reactor, was less than 1 x 10 to the -10th power. The effects of combined neutron/gamma radiation on rubidium frequency standard physics package components were also studied, and the results are presented.

  10. Investigation of radiation detection properties of CRY-018 and CRY-019 scintillators for medical imaging

    NASA Astrophysics Data System (ADS)

    Pani, R.; Colarieti-Tosti, M.; Cinti, M. N.; Polito, C.; Trigila, C.; Ridolfi, S.

    2016-09-01

    During the last years the research for new scintillation crystals has been crucial for the improvement of imaging performance in nuclear medicine applications. Crytur company has recently released two new scintillators named CRY-018 and CRY-019 which are non hygroscopic, have short decay time and low refraction index. They represent the ideal candidates to substitute NaI:Tl and BGO crystals in future PET ad SPECT applications. The purpose of this work is to characterize this unknown crystals, look for possible applications in imaging for nuclear medicine. The results of this work were compared with the results obtained with a LaBr3:ce scintillation crystal. This particular crystal is used as a comparison benchmark because of its strong linear pulse height uniformity response and high energy resolution. Measurements have been performed with a high count rate which is typical for medical applications. Irradiation of the crystals have been performed in three different geometries and in a photon energy range suitable with SPECT and PET applications. The experimental results identify the CRY-018 as an Yttrium and Silicon mixture and the CRY-019 with as Lutetium and Silicon one. Moreover a light yield of about 45% of LaBr3 one, was obtained for both the CRY-018 and CRY-019. This is one of the higher light yield between most of the scintillation crystals usually used in nuclear medicine. Both crystals are characterized by a non-proportionality in the pulse height linearity response. Energy resolutions of 7.4% for CRY-018 and 8.4% for CRY-019 at 661 keV, have been measured. The intrinsic component of the energy resolution has been esteemed for all three scintillators. An intrinsic detection efficiency of about 45% at 122 keV for CRY-018 and 14% at 661 keV for CRY-019 has been measured. Compared with LaBr3:Ce efficiency, which is highly deteriorated by the coating required by the hygroscopicity, CRY-018 and CRY-019 are really interesting considering that these two samples

  11. A radiation-hard, low-background multiplexer design for spacecraft imager applications

    NASA Technical Reports Server (NTRS)

    Staller, Craig; Ramirez, Luis; Niblack, Curtiss; Blessinger, Michael; Kleinhans, William

    1992-01-01

    A possible multiplexer design for the focal plane for the Cassini Visible and Infrared Mapping Spectrometer (VIMS) is reviewed. The instrument's requirements for the multiplexed array are summarized. The VIMS instrument has a modest radiation-hardness requirement due to the trajectory and planetary environments in which the instrument will be required to operate. The total ionizing dose hardness requirement is a few tens of kilorads. A thin-gate oxide of a few hundred angstroms thickness is to be used. Field hardness is to be achieved by guard bands or hardened dielectric isolation. The design is argued to meet the low-noise and radiation-hardness required for imaging at Saturn. The design is versatile enough to provide double-correlated and double-uncorrelated sampling, which is accomplished in the signal processing electronics outside the focal plane.

  12. Test of radiation hardness of CMOS transistors under neutron irradiation

    SciTech Connect

    Sadrozinski, H.F.W.; Rowe, W.A.; Seiden, A.; Spencer, E.; Hoffman, C.M.; Holtkamp, D.; Kinnison, W.W.; Sommer, W.F. Jr.; Ziock, H.J.

    1989-01-01

    We have tested 2 micron CMOS test structures from various foundries in the LAMPF Beam stop for radiation damage under prolongued neutron irradiation. The fluxes employed covered the region expected to be encountered at the SSC and led to fluences of up to 10/sup 14/ neutrons/cm/sup 2/ in about 500 hrs of running. We show that test structures which have been measured to survive ionizing radiation of the order MRad also survive these high neutron fluences. 5 refs., 4 figs.

  13. Influence of Li-codoping on the radiation hardness of CsBr:Eu{sup 2+}

    SciTech Connect

    Zimmermann, J.; Hesse, S.; Seggern, H. von; Fuchs, M.; Knuepfer, W.

    2007-06-01

    The poor radiation hardness of the otherwise excellent x-ray storage phosphor CsBr:Eu{sup 2+} constitutes a problem for its commercial application in medical diagnostics. X-ray induced vacancy centers such as M-centers enhance the diffusion of Eu{sup 2+} activators resulting in a formation of photostimulated luminescence (PSL) inactive europium clusters or second phases of europium compounds. The present study investigates the influence of Li-codoping on the radiation hardness of CsBr:Eu{sup 2+}. It is reported that the integration of Li{sup +} into the CsBr:Eu{sup 2+} suppresses the generation of M-centers during x-irradiation and thereby partially improves the radiation hardness.

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

    SciTech Connect

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

    2008-05-12

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

  15. Light yield measurements of "finger" structured and unstructured scintillators after gamma and neutron irradiation

    NASA Astrophysics Data System (ADS)

    Afanasiev, S. V.; Boyarintsev, A. Yu.; Danilov, M. V.; Emeliantchik, I. F.; Ershov, Yu. V.; Golutvin, I. A.; Grinyov, B. V.; Ibragimova, E.; Levchuk, L. G.; Litomin, A. V.; Makankin, A. M.; Malakhov, A. I.; Moisenz, P. V.; Nuritdinov, I.; Popov, V. F.; Rusinov, V. Yu.; Shumeiko, N. M.; Smirnov, V. A.; Sorokin, P. V.; Tarkovskii, E. I.; Tashmetov, A.; Vasiliev, S. E.; Yuldashev, B.; Zamiatin, N. I.; Zhmurin, P. N.

    2016-05-01

    Plastic scintillators are often used as detectors in High Energy Physics (HEP), but have insufficient radiation hardness. Organization of better light collection inside a single detector may prolong operation life of scintillators. A finger-strip plastic scintillator option has many advantages to keep the excellent detector performance at high luminosity. Measurements assigned to show an advantage of a stripped detector vs. the un-stripped one in the range of increased absorbed doses and the smallest dose rates have been performed. This method has proved to be a good upgrade strategy.

  16. New scintillator and waveshifter materials

    NASA Astrophysics Data System (ADS)

    Zheng, H.; Baumbaugh, B.; Gerig, A.; Hurlbut, C.; Kauffman, J.; Marchant, J.; Pla-Dalmau, A.; Reynolds, K.; Ruchti, R.; Warchol, J.; Wayne, M.

    1998-11-01

    Experimental applications requiring fast timing and/or high efficiency position and energy measurements typically use scintillation materials. Scintillators utilized for triggering, tracking, and calorimetry in colliding beam detectors are vulnerable to the high radiation fields associated with such experiments. We have begun an investigation of several fluorescent dyes which might lead to fast, efficient, and radiation resistant scintillators. Preliminary results of spectral analysis and efficiency are presented.

  17. FPIX2: A radiation-hard pixel readout chip for BTeV

    SciTech Connect

    David C. Christian et al.

    2000-12-11

    A radiation-hard pixel readout chip, FPIX2, is being developed at Fermilab for the recently approved BTeV experiment. Although designed for BTeV, this chip should also be appropriate for use by CDF and DZero. A short review of this development effort is presented. Particular attention is given to the circuit redesign which was made necessary by the decision to implement FPIX2 using a standard deep-submicron CMOS process rather than an explicitly radiation-hard CMOS technology, as originally planned. The results of initial tests of prototype 0.25{micro} CMOS devices are presented, as are plans for the balance of the development effort.

  18. GaN-Based High Temperature and Radiation-Hard Electronics for Harsh Environments

    NASA Technical Reports Server (NTRS)

    Son, Kyung-ah; Liao, Anna; Lung, Gerald; Gallegos, Manuel; Hatakeh, Toshiro; Harris, Richard D.; Scheick, Leif Z.; Smythe, William D.

    2010-01-01

    We develop novel GaN-based high temperature and radiation-hard electronics to realize data acquisition electronics and transmitters suitable for operations in harsh planetary environments. In this paper, we discuss our research on metal-oxide-semiconductor (MOS) transistors that are targeted for 500 (sup o)C operation and >2 Mrad radiation hardness. For the target device performance, we develop Schottky-free AlGaN/GaN MOS transistors, where a gate electrode is processed in a MOS layout using an Al2O3 gate dielectric layer....

  19. GaN-Based High Temperature and Radiation-Hard Electronics for Harsh Environments

    NASA Technical Reports Server (NTRS)

    Son, Kyung-ah; Liao, Anna; Lung, Gerald; Gallegos, Manuel; Hatakeh, Toshiro; Harris, Richard D.; Scheick, Leif Z.; Smythe, William D.

    2010-01-01

    We develop novel GaN-based high temperature and radiation-hard electronics to realize data acquisition electronics and transmitters suitable for operations in harsh planetary environments. In this paper, we discuss our research on metal-oxide-semiconductor (MOS) transistors that are targeted for 500 (sup o)C operation and >2 Mrad radiation hardness. For the target device performance, we develop Schottky-free AlGaN/GaN MOS transistors, where a gate electrode is processed in a MOS layout using an Al2O3 gate dielectric layer....

  20. MNOS/SOS radiation hardness performance and reliability study

    NASA Astrophysics Data System (ADS)

    Hampton, F. L.; Cricchi, J. R.

    1982-05-01

    In this investigation the endurance-retention characteristics of fast-write MNOS memory structure, and radiation tolerance of metal-gate dual-dielectric and polysilicon-gate all-oxide devices have been evaluated. Writing and clearing speed have been studied with respect to the NH3:SiH4 ratio (APCVD), and NH3:SiC12H2 ratio (LPCVD). The films deposited with a low NH3:SiC12 ratios could be written and cleared with shorter pulse widths; however, a degradation in retention was observed. An improvement in the endurance retention product of a drain source protected transistor structure has been realized by oxidizing the memory nitride followed by an H2 anneal immediately after deposition. The film was deposited with a LPCVD reactor at 750 deg with a NH3:SiC12H2 ratio of 9:1. Oxidation was performed in steam at 900 C, as was the subsequent H2 anneal. The effect of total dose radiation was found to be more severe for a positive bias. The all oxide polysilicon gate transistor structures were observed to be relatively soft, however results from capacitor structures shows promise in developing a radiation tolerant polysilicon-gate all-oxide gate structure.

  1. Axial ion-electron emission microscopy of IC radiation hardness

    NASA Astrophysics Data System (ADS)

    Doyle, B. L.; Vizkelethy, G.; Walsh, D. S.; Swenson, D.

    2002-05-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff-Pelletron to velocities of 1.9 MeV/amu. The electronic stopping power for heavy ions is near a maximum at this velocity, and their range is ˜20 μm in Si. These ions therefore represent the most ionizing form of radiation in nature, and are nearly ideal for performing single event effects testing of integrated circuits. Unfortunately, the energy definition of the RFQ-boosted ions is rather poor (˜ a few %), which makes problematic the focussing of such ions to the submicron spots required for REM. To circumvent this problem, we have invented ion electron emission microscopy (IEEM). One can perform REM with the IEEM system without focussing or scanning the ion beam. This is because the position on the sample where each ion strikes is determined by projecting ion-induced secondary electrons at high magnification onto a single electron position sensitive detector. This position signal is then correlated with each REM event. The IEEM system is now mounted along the beam line in an axial geometry so that the ions pass right through the electron detector (which is annular), and all of the electrostatic lenses used for projection. The beam then strikes the sample at normal incidence which results in maximum ion penetration and removes a parallax problem experienced in an earlier system. Details of both the RFQ-booster and the new axial IEEM system are given together with some of the initial results of performing REM on Sandia-manufactured radiation hardened integrated circuits.

  2. Radiation hardness of n-GaN schottky diodes

    SciTech Connect

    Lebedev, A. A. Belov, S. V.; Mynbaeva, M. G.; Strel’chuk, A. M.; Bogdanova, E. V.; Makarov, Yu. N.; Usikov, A. S.; Kurin, S. Yu.; Barash, I. S.; Roenkov, A. D.; Kozlovski, V. V.

    2015-10-15

    Schottky-barrier diodes with a diameter of ∼10 µm are fabricated on n-GaN epitaxial films grown by hydride vapor-phase epitaxy (HVPE) on sapphire substrates. The changes in the parameters of the diodes under irradiation with 15 MeV protons are studied. The carrier removal rate was found to be 130–145 cm{sup –1}. The linear nature of the dependence N = f(D) (N is the carrier concentration, and D, the irradiation dose) shows that compensation of the material is associated with transitions of electrons from shallow donors to deep acceptor levels which are related to primary radiation defects.

  3. A source of hard X-ray radiation based on hybrid X pinches

    NASA Astrophysics Data System (ADS)

    Shelkovenko, T. A.; Pikuz, S. A.; Hoyt, C. L.; Cahill, A. D.; Atoyan, L.; Hammer, D. A.; Tilikin, I. N.; Mingaleev, A. R.; Romanova, V. M.; Agafonov, A. V.

    2016-10-01

    X pinches are well known to produce very small, dense plasma pinches ("hot spots") that emit sub-nanosecond bursts of 1-8 keV radiation. Hard X-ray radiation in the range from 8 to 300 keV or more is also emitted, and only a small portion of which is associated with the X-pinch hot spot. In hybrid X-pinches (HXP), the 10 ns hard X-ray pulse is terminated by fast closure of the gap between the two conical electrodes of the HXP by rapidly expanding electrode plasmas. The temporal, spectral, and spatial properties of this higher energy radiation have been studied. This radiation was used for point-projection imaging with magnification between 1.5 and 6, and spatial resolution of 20-100 μm was demonstrated.

  4. Hard X-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.

    1981-01-01

    Past hard X-ray and lower energy satellite instruments are reviewed and it is shown that observation above 20 keV and up to hundreds of keV can provide much valuable information on the astrophysics of cosmic sources. To calculate possible sensitivities of future arrays, the efficiencies of a one-atmosphere inch gas counter (the HEAO-1 A-2 xenon filled HED3) and a 3 mm phoswich scintillator (the HEAO-1 A-4 Na1 LED1) were compared. Above 15 keV, the scintillator was more efficient. In a similar comparison, the sensitivity of germanium detectors did not differ much from that of the scintillators, except at high energies where the sensitivity would remain flat and not rise with loss of efficiency. Questions to be addressed concerning the physics of active galaxies and the diffuse radiation background, black holes, radio pulsars, X-ray pulsars, and galactic clusters are examined.

  5. Hierarchical radioscopy using polychromatic and partially coherent hard synchrotron radiation.

    PubMed

    Rack, Alexander; García-Moreno, Francisco; Helfen, Lukas; Mukherjee, Manas; Jiménez, Catalina; Rack, Tatjana; Cloetens, Peter; Banhart, John

    2013-11-20

    Pushing synchrotron x-ray radiography to increasingly higher image-acquisition rates (currently up to 100,000 fps) while maintaining spatial resolutions in the micrometer range implies drastically reduced fields of view. As a consequence, either imaging a small subregion of the sample with high spatial resolution or only the complete specimen with moderate resolution is applicable. We introduce a concept to overcome this limitation by making use of a semi-transparent x-ray detector positioned close to the investigated sample. The hard x-rays that pass through the sample either create an image on the first detector or keep on propagating until they are captured by a second x-ray detector located further downstream. In this way, a process can be imaged simultaneously in a hierarchical manner within a single exposure and a projection of the complete object with moderate resolution as well as a subregion with high resolution are obtained. As a proof-of-concept experiment, image sequences of an evolving liquid-metal foam are shown, employing frame rates of 1000  images/s (1.2 μm pixel size) and 15,000  images/s (18.1 μm pixel size) for the first and second detector, respectively.

  6. Radiation hardness of 3HF-tile/O2-WLS-fiber calorimeter

    SciTech Connect

    Han, S.W.; Hu, L.D.; Liu, N.Z.

    1993-11-01

    The radiation hardness of a 3HF-tile/O2-WLS-fiber calorimeter with two different tile/fiber patterns has been studied. Two calorimeter modules were irradiated up to 10 Mrad with the BEPC 1.3 GeV electron beam. The radiation damage of these modules is compared with our previous measurements from SCSN81-tile/BCF91A-WLS-fiber modules. The longitudinal damage profiles are fitted as a function of depth.

  7. Radiation hard programmable delay line for LHCb calorimeter upgrade

    NASA Astrophysics Data System (ADS)

    Mauricio, J.; Gascón, D.; Vilasís, X.; Picatoste, E.; Machefert, F.; Lefrancois, J.; Duarte, O.; Beigbeder, C.

    2014-01-01

    This paper describes the implementation of a SPI-programmable clock delay chip based on a Delay Locked Loop (DLL) in order to shift the phase of the LHC clock (25 ns) in steps of 1ns, with less than 5 ps jitter and 23 ps of DNL. The delay lines will be integrated into ICECAL, the LHCb calorimeter front-end analog signal processing ASIC in the near future. The stringent noise requirements on the ASIC imply minimizing the noise contribution of digital components. This is accomplished by implementing the DLL in differential mode. To achieve the required radiation tolerance several techniques are applied: double guard rings between PMOS and NMOS transistors as well as glitch suppressors and TMR Registers. This 5.7 mm2 chip has been implemented in CMOS 0.35 μm technology.

  8. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology

    NASA Technical Reports Server (NTRS)

    Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; LaBel, K. A.

    2015-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the design margin concept with one of failure probability.

  9. Method of making a scintillator waveguide

    DOEpatents

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

    2000-01-01

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

  10. Development of a proportional scintillation x-ray imaging chamber for synchrotron radiation experiments

    NASA Astrophysics Data System (ADS)

    Suzuki, Masayo; Takahashi, Tan; Awaya, Yohko; Oura, Masaki; Yamamoto, Masaki; Uruga, Tomoya; Mizogawa, Tatsumi; Masuda, Kimiaki

    1995-02-01

    Proportional scintillation x-ray imaging chamber (PSXIC) is a new type of two-dimensional position-sensitive x-ray detector composed of a spherical drift chamber, a parallel plate avalanche counter, and an image-intensifier-associated charge coupled device camera. A prototype of PSXIC filled with xenon (97%)+triethylamine (3%) gaseous mixture has been stably operated under a high flux of x-ray irradiation. The spatial resolution the prototype can attain has been found better than 800 μm. The time-resolved imaging capability has also been examined by taking time-varying x-ray images of a test pattern with a time resolution of 1/30 s.

  11. A reliability simulator for radiation-hard microelectronics development

    NASA Astrophysics Data System (ADS)

    Huang, David H.; King, Everett E.; Wang, J. J.

    1991-07-01

    A real-time reliability simulator to predict device lifetime of n-channel MOSFET transistors due to channel hot-electron (CHE) degradation was developed. The correlation between the x ray radiation induced and hot-electron induced interface state generation was established for both conventional non-LDD and the LDD n-channel devices by using appropriate failure criteria. The correlation has been confirmed by the charge pumping measurements. Software modules were developed to control the hardware of the simulator, collect the data and perform the data analysis. The benefit of this stimulator is dramatically reduced test time. A new hot-carrier stress test procedure has been developed based on the constant gate current stress to evaluate the hot-carrier induced device lifetime of p-channel transistors. This approach ensures a constant electric field near the drain and the constant electron injection rate. It becomes possible to compare the hot-carrier sensitivity of p-channel devices from different process technologies.

  12. Monitoring system for testing the radiation hardness of a KINTEX-7 FPGA

    SciTech Connect

    Cojocariu, L. N.; Placinta, V. M.; Dumitru, L.

    2016-03-25

    A much more efficient Ring Imaging Cherenkov sub-detector system will be rebuilt in the second long shutdown of Large Hadron Collider for the LHCb experiment. Radiation-hard electronic components together with Commercial Off-The-Shelf ones will be used in the new Cherenkov photon detection system architecture. An irradiation program was foreseen to determine the radiation tolerance for the new electronic devices, including a Field Programmable Gate Array from KINTEX-7 family of XILINX. An automated test bench for online monitoring of the XC7K70T KINTEX-7 device operation in radiation conditions was designed and implemented by the LHCb Romanian group.

  13. Creation of a Radiation Hard 0.13 Micron CMOS Library at IHP

    NASA Astrophysics Data System (ADS)

    Jagdhold, U.

    2010-08-01

    To support space applications we will develop an 0.13 micron CMOS library which should be radiation hard up to 200 krad. By introducing new radiation hard design rules we will minimize IC-level leakage and single event latchup (SEL). To reduce single event upset (SEU) we will add two p-MOS transistors to all flip flops. For reliability reasons we will use double contacts in all library elements. The additional rules and the library elements will then be integrated in our Cadence mixed signal designkit, Virtuoso IC6.1 [1]. A test chip will be produced with our in house 0.13 micron BiCMOS technology, see Ref. [2].Thereafter we will doing radiation tests according the ESA specifications, see Ref. [3], [4].

  14. Impact of Radiation Hardness and Operating Temperatures of Silicon Carbide Electronics on Space Power System Mass

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Tew, Roy C.; Schwarze, Gene E.

    1998-01-01

    The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kW(e) , 1 MW(e), and 10 MW(e)) for near term technology ( i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature Gas Reactor (HTGR) heat source. The study was conducted for assumed PC radiator temperatures ranging from 370 to 845 K and for three scenarios of electrical energy to heat conversion levels which needed to be rejected to space by means of the PC radiator. In addition, during part of the study the radiation hardness of the PC electronics was varied at a fixed separation distance to estimate its effect on the mass of the instrument rated reactor shadow shield. With both the PC radiator and the conical shadow shield representing major components of the overall power system the influence of the above on total power system mass was also determined. As expected, results show that the greatest actual mass savings achieved by the use of SiC electronics occur with high capacity power systems. Moreover, raising the PC radiator temperature above 600 K yields only small additional system mass savings. The effect of increased radiation hardness on total system mass is to reduce system mass by virtue of lowering the shield mass.

  15. OSSE observations of Galactic 511 keV positron annihilation radiation - Initial phase 1 results. [Oriented Scintillation Spectrometer Experiment

    NASA Technical Reports Server (NTRS)

    Purcell, W. R.; Grabelsky, D. A.; Ulmer, M. P.; Johnson, W. N.; Kinzer, R. L.; Kurfess, J. D.; Strickman, M. S.; Jung, G. V.

    1993-01-01

    The Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Gamma-Ray Observatory (GRO) has performed numerous observations of the Galactic plane and Galactic center region to measure the distribution of Galactic 511 keV positron annihilation radiation and to search for time variability of the emission. The initial 511 keV line fluxes for the observations performed during the first 18 months of the GRO mission are presented. The 511 keV line flux for a typical Galactic center observation is (2.5 +/- 0.3) x 10 exp -4 gamma/sq cm per sec, where the quoted uncertainty represents the 1 sigma statistical uncertainty. No statistically significant time variability of the line flux has been observed; the 3 sigma upper limit to daily variations from the mean is 3 x 10 exp -4 gamma/sq cm per sec. The distribution of Galactic 511 keV positron annihilation radiation implied by the OSSE observations is discussed and compared with observations by other instruments.

  16. OSSE observations of Galactic 511 keV positron annihilation radiation - Initial phase 1 results. [Oriented Scintillation Spectrometer Experiment

    NASA Technical Reports Server (NTRS)

    Purcell, W. R.; Grabelsky, D. A.; Ulmer, M. P.; Johnson, W. N.; Kinzer, R. L.; Kurfess, J. D.; Strickman, M. S.; Jung, G. V.

    1993-01-01

    The Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Gamma-Ray Observatory (GRO) has performed numerous observations of the Galactic plane and Galactic center region to measure the distribution of Galactic 511 keV positron annihilation radiation and to search for time variability of the emission. The initial 511 keV line fluxes for the observations performed during the first 18 months of the GRO mission are presented. The 511 keV line flux for a typical Galactic center observation is (2.5 +/- 0.3) x 10 exp -4 gamma/sq cm per sec, where the quoted uncertainty represents the 1 sigma statistical uncertainty. No statistically significant time variability of the line flux has been observed; the 3 sigma upper limit to daily variations from the mean is 3 x 10 exp -4 gamma/sq cm per sec. The distribution of Galactic 511 keV positron annihilation radiation implied by the OSSE observations is discussed and compared with observations by other instruments.

  17. Application of two-photon absorption in PWO scintillator for fast timing of interaction with ionizing radiation

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Buganov, O.; Korjik, M.; Fedorov, A.; Nargelas, S.; Tamulaitis, G.; Tikhomirov, S.; Vaitkevičius, A.

    2015-12-01

    This work was aimed at searching for fast phenomena in scintillators in sub-10-ps range, a benchmark timing for the time response of radiation detectors in particle colliders. The pump-and-probe optical absorption technique with a tunable-wavelength parametric oscillator as the pump and a continuous-spectrum source as the probe beam was used to study lead tungstate PbWO4 (PWO) single crystals. It is shown that the rise time of the probe pulse absorption induced by the pump pulse is shorter than the pump pulse width of 200 fs. The approximately linear dependence of the probe absorption on the pump pulse energy density evidences that the induced absorption is caused by two-photon absorption involving one probe and one pump photon. We demonstrate that the intensity of the induced absorption at certain wavelengths is influenced by gamma irradiation, provided that an appropriate light polarization is selected. The application of the irradiation-sensitive nonlinearity for fast timing in radiation detectors is discussed.

  18. Extreme Radiation Hardness and Space Qualification of AlGaN Optoelectronic Devices

    SciTech Connect

    Sun, Ke-Xun; Balakrishnan, Kathik; Hultgren, Eric; Goebel, John; Bilenko, Yuri; Yang, Jinwei; Sun, Wenhong; Shatalov, Max; Hu, Xuhong; Gaska, Remis

    2010-09-21

    Unprecedented radiation hardness and environment robustness are required in the new generation of high energy density physics (HEDP) experiments and deep space exploration. National Ignition Facility (NIF) break-even shots will have a neutron yield of 1015 or higher. The Europa Jupiter System Mission (EJSM) mission instruments will be irradiated with a total fluence of 1012 protons/cm2 during the space journey. In addition, large temperature variations and mechanical shocks are expected in these applications under extreme conditions. Hefty radiation and thermal shields are required for Si and GaAs based electronics and optoelectronics devices. However, for direct illumination and imaging applications, shielding is not a viable option. It is an urgent task to search for new semiconductor technologies and to develop radiation hard and environmentally robust optoelectronic devices. We will report on our latest systematic experimental studies on radiation hardness and space qualifications of AlGaN optoelectronic devices: Deep UV Light Emitting Diodes (DUV LEDs) and solarblind UV Photodiodes (PDs). For custom designed AlGaN DUV LEDs with a central emission wavelength of 255 nm, we have demonstrated its extreme radiation hardness up to 2x1012 protons/cm2 with 63.9 MeV proton beams. We have demonstrated an operation lifetime of over 26,000 hours in a nitrogen rich environment, and 23,000 hours of operation in vacuum without significant power drop and spectral shift. The DUV LEDs with multiple packaging styles have passed stringent space qualifications with 14 g random vibrations, and 21 cycles of 100K temperature cycles. The driving voltage, current, emission spectra and optical power (V-I-P) operation characteristics exhibited no significant changes after the space environmental tests. The DUV LEDs will be used for photoelectric charge management in space flights. For custom designed AlGaN UV photodiodes with a central response wavelength of 255 nm, we have demonstrated

  19. SCINTILLATION EXPOSURE RATE DETECTOR

    DOEpatents

    Spears, W.G.

    1960-11-01

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

  20. Microprocessing of human hard tooth tissues surface by mid-infrared erbium lasers radiation

    NASA Astrophysics Data System (ADS)

    Belikov, Andrey V.; Shatilova, Ksenia V.; Skrypnik, Alexei V.

    2015-03-01

    A new method of hard tooth tissues laser treatment is described. The method consists in formation of regular microdefects on tissue surface by mid-infrared erbium laser radiation with propagation ratio M2<2 (Er-laser microprocessing). Proposed method was used for preparation of hard tooth tissues surface before filling for improvement of bond strength between tissues surface and restorative materials, microleakage reduction between tissues surface and restorative materials, and for caries prevention as a result of increasing microhardness and acid resistance of tooth enamel.

  1. Medium-induced gluon radiation in hard forward parton scattering in the saturation formalism

    NASA Astrophysics Data System (ADS)

    Munier, Stéphane; Peigné, Stéphane; Petreska, Elena

    2017-01-01

    We derive the medium-induced, fully coherent soft gluon radiation spectrum associated with the hard forward scattering of an energetic parton off a nucleus, in the saturation formalism within the Gaussian approximation for the relevant correlators of Wilson lines and for finite number of colors. The validity range of the result is rigorously specified by keeping track of the order of magnitude of subleading contributions to the spectrum. The connection between the saturation formalism and the opacity expansion used in previous studies of the same observable is made apparent. Our calculation sets the basis for further studies of the interplay between saturation and fully coherent energy loss in hard forward parton scattering.

  2. Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak

    SciTech Connect

    Rasouli, C.; Pourshahab, B.; Rasouli, H.; Hosseini Pooya, S. M.; Orouji, T.

    2014-05-15

    In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points – three TLDs per point – to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

  3. Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak.

    PubMed

    Rasouli, C; Pourshahab, B; Hosseini Pooya, S M; Orouji, T; Rasouli, H

    2014-05-01

    In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points--three TLDs per point--to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

  4. Doping of polysiloxane rubbers for the production of organic scintillators

    NASA Astrophysics Data System (ADS)

    Quaranta, A.; Carturan, S.; Marchi, T.; Cinausero, M.; Scian, C.; Kravchuk, V. L.; Degerlier, M.; Gramegna, F.; Poggi, M.; Maggioni, G.

    2010-08-01

    Polysiloxane rubbers have been produced with different concentrations of phenyl groups and of dye molecules in order to find the best synthesis conditions for reaching a high light yield. In particular, two different polymer compositions were examined, namely with 15% and 22% of phenyl units in the starting resin. 2,5-Diphenyl oxazole (PPO) as a primary dopant and Lumogen F Violet 570 as secondary dopant were dispersed in the polysiloxane. Ion beam induced luminescence (IBIL) technique was employed for studying radioluminescence and radiation hardness properties. The α and γ scintillation yields were analyzed by measuring the pulse height spectra from 241Am and 60Co radioactive sources. First tests on the suitability of these materials to the detection of fast neutrons were also performed with a TOF procedure. Preliminary results indicate that these materials exhibit a scintillation yield comparable with NE102 plastic scintillator.

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

    SciTech Connect

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

    2011-07-01

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

  6. Radiation hard silicon particle detectors for HL-LHC-RD50 status report

    NASA Astrophysics Data System (ADS)

    Terzo, S.

    2017-02-01

    It is foreseen to significantly increase the luminosity of the LHC by upgrading towards the HL-LHC (High Luminosity LHC). The Phase-II-Upgrade scheduled for 2024 will mean unprecedented radiation levels, way beyond the limits of the silicon trackers currently employed. All-silicon central trackers are being studied in ATLAS, CMS and LHCb, with extremely radiation hard silicon sensors to be employed on the innermost layers. Within the RD50 Collaboration, a massive R&D program is underway across experimental boundaries to develop silicon sensors with sufficient radiation tolerance. We will present results of several detector technologies and silicon materials at radiation levels corresponding to HL-LHC fluences. Based on these results, we will give recommendations for the silicon detectors to be used at the different radii of tracking systems in the LHC detector upgrades. In order to complement the measurements, we also perform detailed simulation studies of the sensors.

  7. Effect of radiation light characteristics on surface hardness of paint-on resin for shade modification.

    PubMed

    Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Ban, Seiji

    2005-12-01

    The purpose of this study was to investigate the effect of radiation light characteristics--of different types of clinical light-curing unit--on polymerization efficiency, as determined by the surface hardness of light-cured paint-on resins. Four shades of paint-on resin for shade modification of restorative resins were used. Materials were cured using one laboratory and three clinical light-curing units with different light sources, namely tungsten-halogen, LED, plasma arc, and xenon flash lamps. Knoop hardness measurements were taken at both the top and bottom surfaces of the specimens to assess the mechanical properties and degree of polymerization. Both LED and plasma arc light units caused significantly poorer surface hardness than the halogen and laboratory xenon lights. In addition, the transparent shade was more sensitive to surface hardness than other chromatic shades. Our results indicated that the polymerization efficiency of paint-on resin was significantly influenced by the radiation light characteristics of clinical light-curing units.

  8. Comparison of proton microbeam and gamma irradiation for the radiation hardness testing of silicon PIN diodes

    NASA Astrophysics Data System (ADS)

    Jakšić, M.; Grilj, V.; Skukan, N.; Majer, M.; Jung, H. K.; Kim, J. Y.; Lee, N. H.

    2013-09-01

    Simple and cost-effective solutions using Si PIN diodes as detectors are presently utilized in various radiation-related applications in which excessive exposure to radiation degrades their charge transport properties. One of the conventional methods for the radiation hardness testing of such devices is time-consuming irradiation with electron beam or gamma-ray irradiation facilities, high-energy proton accelerators, or with neutrons from research reactors. Recently, for the purpose of radiation hardness testing, a much faster nuclear microprobe based approach utilizing proton irradiation has been developed. To compare the two different irradiation techniques, silicon PIN diodes have been irradiated with a Co-60 gamma radiation source and with a 6 MeV proton microbeam. The signal degradation in the silicon PIN diodes for both irradiation conditions has been probed by the IBIC (ion beam induced charge) technique, which can precisely monitor changes in charge collection efficiency. The results presented are reviewed on the basis of displacement damage calculations and NIEL (non-ionizing energy loss) concept.

  9. DSB:Ce3+ scintillation glass for future

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Akchurin, N.; Benaglia, A.; Borisevich, A.; Cowden, C.; Damgov, J.; Dormenev, V.; Dragoiu, C.; Dudero, P.; Korjik, M.; Kozlov, D.; Kunori, S.; Lecoq, P.; Lee, S. W.; Lucchini, M.; Mechinsky, V.; Pauwels, K.

    2015-02-01

    One of the main challenges for detectors at future high-energy collider experiments is the high precision measurement of hadron and jet energy and momentum. One possibility to achieve this is the dual-readout technique, which allows recording simultaneously scintillation and Cherenkov light in an active medium in order to extract the electromagnetic fraction of the total shower energy on an event- by-event basis. Making use of this approach in the high luminosity LHC, however, puts stringent requirements on the active materials in terms of radiation hardness. Consequently, the R&D carried out on suitable scintillating materials focuses on the detector performance as well as on radiation tolerance. Among the different scintillating materials under study, scintillating glasses can be a suitable solution due to their relatively simple and cost effective production. Recently a new type of inorganic scintillating glass: Cerium doped DSB has been developed by Radiation Instruments and New Components LLC in Minsk for oil logging industry. This material can be produced either in form of bulk or fiber shape with diameter 0.3-2mm and length up to 2000 mm. It is obtained by standard glass production technology at temperature 1400°C with successive thermal annealing treatment at relatively low temperature. The production of large quantities is relatively easy and the production costs are significantly lower compared to crystal fibers. Therefore, this material is considered as an alternative and complementary solution to crystal fibers in view of a production at industrial scale, as required for a large dual readout calorimeter. In this paper, the first results on optical, scintillation properties as well as the radiation damage behaviour obtained on different samples made with different raw materials and various cerium concentrations will be presented.

  10. Development of High Quantum Efficiency UV/Blue Photocathode Epitaxial Semiconductor Heterostructures for Scintillation and Cherenkov Radiation Detection

    NASA Technical Reports Server (NTRS)

    Leopold, Daniel J.

    2002-01-01

    The primary goal of this research project was to further extend the use of advanced heteroepitaxial-semiconductor crystal growth techniques such as molecular beam epitaxy (MBE) and to demonstrate significant gains in UV/blue photonic detection by designing and fabricating atomically-tailored heteroepitaxial GaAlN/GaInN photocathode device structures. This NASA Explorer technology research program has focused on the development of photocathodes for Cherenkov and scintillation radiation detection. Support from the program allowed us to enhance our MBE system to include a nitrogen plasma source and a magnetic bearing turbomolecular pump for delivery and removal of high purity atomic nitrogen during GaAlN/GaInN film growth. Under this program we have also designed, built and incorporated a cesium activation stage. In addition, a connected UHV chamber with photocathode transfer/positioner components as well as a hybrid phototube stage was designed and built to make in-situ quantum efficiency measurements without ever having to remove the photocathodes from UHV conditions. Thus we have constructed a system with the capability to couple atomically-tailored MBE-grown photocathode heterostructures with real high gain readout devices for single photon detection evaluation.

  11. Search for new scintillators by studying the fluorescence properties of powdered compounds with synchrotron radiation.

    PubMed

    Dewu, W; Jianfei, L; Yaning, X; Yifan, G; Yu, C; Hancheng, S; Jiashan, Z; Zuqi, Z

    1995-03-01

    This paper describes a method for investigating the properties of powdered compounds using synchrotron X-radiation. The fluorescence decay times of bismuth germanate, BaF(2), CeF(3) and CsI, as well as the light yields of several samples of gadolinium silicate, prepared in different ways, have been measured.

  12. Development of intrinsic IPT scintillator

    SciTech Connect

    Bross, A.D.

    1989-07-31

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

  13. Assessing the performance under ionising radiation of lead tungstate scintillators for EM calorimetry in the CLAS12 Forward Tagger

    NASA Astrophysics Data System (ADS)

    Fegan, S.; Auffray, E.; Battaglieri, M.; Buchanan, E.; Caiffi, B.; Celentano, A.; Colaneri, L.; D`Angelo, A.; De Vita, R.; Dormenev, V.; Fanchini, E.; Lanza, L.; Novotny, R. W.; Parodi, F.; Rizzo, A.; Sokhan, D.; Tarasov, I.; Zonta, I.

    2015-07-01

    The well-established technology of electromagnetic calorimetry using Lead Tungstate crystals has recently seen an upheaval, with the closure of one of the most experienced large-scale suppliers of such crystals, the Bogoroditsk Technical Chemical Plant (BTCP), which was instrumental in the development of mass production procedures for PWO-II, the current benchmark for this scintillator. Obtaining alternative supplies of Lead Tungstate crystals matching the demanding specifications of contemporary calorimeter devices now presents a significant challenge to detector research and development programmes. In this paper we describe a programme of assessment carried out for the selection, based upon the performance under irradiation, of Lead Tungstate crystals for use in the Forward Tagger device, part of the CLAS12 detector in Hall B at Jefferson Lab. The crystals tested were acquired from SICCAS, the Shanghai Institute of Ceramics, Chinese Academy of Sciences. The tests performed are intended to maximise the performance of the detector within the practicalities of the crystal manufacturing process. Results of light transmission, before and after gamma ray irradiation, are presented and used to calculate dk, the induced radiation absorption coefficient, at 420 nm, the peak of the Lead Tungstate emission spectrum. Results for the SICCAS crystals are compared with identical measurements carried out on Bogoroditsk samples, which were acquired for the Forward Tagger development program before the closure of the facility. Also presented are a series of tests performed to determine the feasibility of recovering radiation damage to the crystals using illumination from an LED, with such illumination available in the Forward Tagger from a light monitoring system integral to the detector.

  14. The role of radiation hard solar cells in minimizing the costs of global satellite communication systems

    NASA Technical Reports Server (NTRS)

    Summers, Geoffrey P.; Walters, Robert J.; Messenger, Scott R.; Burke, Edward A.

    1996-01-01

    An analysis embodied in a PC computer program is presented, which quantitatively demonstrates how the availability of radiation hard solar cells can help minimize the cost of a global satellite communications system. An important distinction between the currently proposed systems, such as Iridium, Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation at orbital altitudes within the earth's radiation belts (10(exp 3) to 10(exp 4)km) can reduce the total cost of a system by several hundred percent, so long as radiation hard components including solar cells can be used. A detailed evaluation of the predicted performance of photovoltaic arrays using several different planar solar cell technologies is given, including commercially available Si and GaAs/Ge, and InP/Si which is currently under development. Several examples of applying the program are given, which show that the end of life (EOL) power density of different technologies can vary by a factor of ten for certain missions. Therefore, although a relatively radiation-soft technology can usually provide the required EOL power by simply increasing the size of the array, the impact upon the total system budget could be unacceptable, due to increased launch and hardware costs. In aggregate, these factors can account for more than a 10% increase in the total system cost. Since the estimated total costs of proposed global-coverage systems range from $1B to $9B, the availability of radiation-hard solar cells could make a decisive difference in the selection of a particular constellation architecture.

  15. The role of radiation hard solar cells in minimizing the costs of global satellite communication systems

    NASA Technical Reports Server (NTRS)

    Summers, Geoffrey P.; Walters, Robert J.; Messenger, Scott R.; Burke, Edward A.

    1996-01-01

    An analysis embodied in a PC computer program is presented, which quantitatively demonstrates how the availability of radiation hard solar cells can help minimize the cost of a global satellite communications system. An important distinction between the currently proposed systems, such as Iridium, Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation at orbital altitudes within the earth's radiation belts (10(exp 3) to 10(exp 4)km) can reduce the total cost of a system by several hundred percent, so long as radiation hard components including solar cells can be used. A detailed evaluation of the predicted performance of photovoltaic arrays using several different planar solar cell technologies is given, including commercially available Si and GaAs/Ge, and InP/Si which is currently under development. Several examples of applying the program are given, which show that the end of life (EOL) power density of different technologies can vary by a factor of ten for certain missions. Therefore, although a relatively radiation-soft technology can usually provide the required EOL power by simply increasing the size of the array, the impact upon the total system budget could be unacceptable, due to increased launch and hardware costs. In aggregate, these factors can account for more than a 10% increase in the total system cost. Since the estimated total costs of proposed global-coverage systems range from $1B to $9B, the availability of radiation-hard solar cells could make a decisive difference in the selection of a particular constellation architecture.

  16. Satellite project "CORONAS-PHOTON" for study of solar hard radiation

    NASA Astrophysics Data System (ADS)

    Kotov, Yu.; Cor-Phot Team

    "CORONAS-PHOTON" is the Russian mission for study of the solar hard electromagnetic radiation in the very wide energy range from Extreme UV up to high-energy gamma - radiation. GOAL OF PROJECT: The investigation of energy accumulation and its transformation into energy of accelerated particles processes during solar flares; the study of the acceleration mechanisms, propagation and interaction of fast particles in the solar atmosphere; the study of the solar activity correlation with physical-chemical processes in the Earth upper atmosphere. SCIENTIFIC PAYLOAD CAPABILITY Radiation / Energy region / Detector type: Full solar disk X- radiation / 2keV - 2000MeV / Prop. counter; NaI(Tl); Full solar disk X- and γ-radiation / NaI(Tl)/CsI(Na) phoswich; Full solar disk X- and γ-radiation and solar neutrons / 20 - 300MeV / YalO_3(Ce); CsI(Tl); Hard X-ray polarization in large flares / 20 - 150keV / p-terphenyl scatterer and CsI(Na) absorbers; Full solar disk EUV-radiation monitoring / 6 spectral windows in <10 - 130nm / Filtered photodiodes; Solar images in narrow spectral bands and monochromatic emission lines of hot plasma / Emission of HeII, SiXI, FeXXI, FeXXIII, MgXII ions / Multi-layer and Bregg spherical crystal quartz mirrors with CCDs; Additionally, the temporal and energy spectra of electrons (0.2-14MeV), protons (1-61MeV) and nuclei (Z<26, 2-50MeV/nuclon) at the satellite orbit will be registrated by several instruments. MAIN CHARACTERISTICS OF SPACECRAFT: Spacecraft weight: 1900 kg; Orbit type: Circular; Scientific payload weight: 540 kg; Height: 500 km; Orientation to the Sun [arc min]: better 5; Inclination: 82.5 degree; Instability of orientation [deg/s]: less 0.005; Solar - synchronous orbit is under study. Launching date of "CORONAS-PHOTON" spacecraft is 2006.

  17. Extruded plastic scintillator including inorganic powders

    DOEpatents

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

    2006-06-27

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

  18. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Low-threshold generation of harmonics and hard x radiation in a laser plasma. 2. Multipeak generation

    NASA Astrophysics Data System (ADS)

    Apollonov, V. V.; Derzhavin, S. I.; Kazakov, K. Kh

    1993-02-01

    The conditions for the generation of hard x radiation with a multipeak structure in a plasma pumped by a long pulse from a free-running CO2 laser at a low intensity (q≲10 GW/cm2) have been studied. This x-ray generation had been observed in a previous study by the present authors. It is shown that this generation of hard x radiation with a multipeak structure leads to a more than tenfold increase in the yield of hard x radiation per laser pulse, under optimum conditions. This increase results from the additional peaks in the x-ray signal. An explanation of this effect is proposed.

  19. Bridgman Growth of Large SrI2:Eu2+ Single Crystals: A High-performance Scintillator for Radiation Detection Applications

    SciTech Connect

    Boatner, Lynn A; Ramey, Joanne Oxendine; Kolopus, James A; Hawrami, Rastgo; Higgins, William; Van Loef, Edgar; Glodo, J.; Shah, Kanai; Bhattacharya, P.; Tupitsyn, E; Groza, Michael; Burger, Arnold

    2013-01-01

    Single-crystal strontium iodide (SrI2) doped with relatively high levels (e.g., 3 - 6 %) of Eu2+ exhibits characteristics that make this material superior, in a number of respects, to other scintillators that are currently used for radiation detection. Specifically, SrI2:Eu2+ has a light yield that is significantly higher than LaBr3:Ce3+ -a currently employed commercial high-performance scintillator. Additionally, SrI2:Eu2+ is characterized by an energy resolution as high as 2.6% at the 137Cs gamma-ray energy of 662 keV, and there is no radioactive component in SrI2:Eu2+ - unlike LaBr3:Ce3+ that contains 138La. The Ce3+-doped LaBr3 decay time is, however, faster (30 nsec) than the 1.2 sec decay time of SrI2:Eu2+. Due to the relatively low melting point of strontium iodide (~515 oC), crystal growth can be carried out in quartz crucibles by the vertical Bridgman technique. Materials-processing and crystal-growth techniques that are specific to the Bridgman growth of europium-doped strontium iodide scintillators are described here. These techniques include the use of a porous quartz frit to physically filter the molten salt from a quartz antechamber into the Bridgman growth crucible and the use of a bent or bulb grain selector design to suppress multiple grain growth. Single crystals of SrI2:Eu2+ scintillators with good optical quality and scintillation characteristics have been grown in sizes up to 5.0 cm in diameter by applying these techniques. Other aspects of the SrI2:Eu2+ crystal-growth methods and of the still unresolved crystal-growth issues are described here.

  20. Bridgman growth of large SrI2:Eu2+ single crystals: A high-performance scintillator for radiation detection applications

    NASA Astrophysics Data System (ADS)

    Boatner, L. A.; Ramey, J. O.; Kolopus, J. A.; Hawrami, R.; Higgins, W. M.; van Loef, E.; Glodo, J.; Shah, K. S.; Rowe, Emmanuel; Bhattacharya, Pijush; Tupitsyn, Eugene; Groza, Michael; Burger, Arnold; Cherepy, N. J.; Payne, S. A.

    2013-09-01

    Single-crystal strontium iodide (SrI2) doped with relatively high levels (e.g., 3-6%) of Eu2+ exhibits characteristics that make this material superior, in a number of respects, to other scintillators that are currently used for radiation detection. Specifically, SrI2:Eu2+ has a light yield that is significantly higher than LaBr3:Ce3+—a currently employed commercial high-performance scintillator. Additionally, SrI2:Eu2+ is characterized by an energy resolution as high as 2.6% at the 137Cs gamma-ray energy of 662 keV, and there is no radioactive component in SrI2:Eu2+—unlike LaBr3:Ce3+ that contains 138La. The Ce3+-doped LaBr3 decay time is, however, faster (30 ns) than the 1.2 μs decay time of SrI2:Eu2+. Due to the relatively low melting point of strontium iodide (˜515 °C), crystal growth can be carried out in quartz crucibles by the vertical Bridgman technique. Materials-processing and crystal-growth techniques that are specific to the Bridgman growth of europium-doped strontium iodide scintillators are described here. These techniques include the use of a porous quartz frit to physically filter the molten salt from a quartz antechamber into the Bridgman growth crucible and the use of a "bent" or "bulb" grain selector design to suppress multiple grain growth. Single crystals of SrI2:Eu2+ scintillators with good optical quality and scintillation characteristics have been grown in sizes up to 5.0 cm in diameter by applying these techniques. Other aspects of the SrI2:Eu2+ crystal-growth methods and of the still unresolved crystal-growth issues are described here.

  1. Scintillator material

    DOEpatents

    Anderson, David F.; Kross, Brian J.

    1992-01-01

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

  2. Scintillator material

    DOEpatents

    Anderson, David F.; Kross, Brian J.

    1994-01-01

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

  3. Scintillator material

    DOEpatents

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

    1992-07-28

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

  4. Scintillator material

    DOEpatents

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

    1994-06-07

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

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

    SciTech Connect

    Moss, C.E.

    1994-12-31

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

  6. On the nature of the sources of hard pulse X-ray radiation

    NASA Technical Reports Server (NTRS)

    Shklovskiy, I. S.

    1978-01-01

    Besides the identified sources of cosmic pulse X-ray radiation with globular clusters NGC 6624, NGC 1851 and MXB 1730-335 several new identifications were made. The source in Norma was probably identified with globular cluster NGC 5927, the source in Aquila with globular cluster NGC 6838 (M71), and the source in Puppis with globular cluster NGC 2298. Gamma pulses discovered by the Vela satellites and X-ray pulses thoroughly measured by the SAS-3, Ariel-5, and ANS satellites are thought to be the same phenomenon. The sources of such a radiation must be some kind of peculiarity at the central part of globular clusters; it is most probably a massive black hole. The sources of hard pulse radiation which cannot be identified with globular clusters are considered to be a new kind of galactic object, invisible globular clusters, which are naked nuclei of globular clusters.

  7. Radiation Hardness Tests of SiPMs for the JLab Hall D Barrel Calorimeter

    SciTech Connect

    Yi Qiang, Carl Zorn, Fernando Barbosa, Elton Smith

    2013-01-01

    We report on the measurement of the neutron radiation hardness of silicon photomultipliers (SiPMs) manufactured by Hamamatsu Corporation in Japan and SensL in Ireland. Samples from both companies were irradiated by neutrons created by a 1 GeV electron beam hitting a thin lead target at Jefferson Lab Hall A. More tests regarding the temperature dependence of the neutron radiation damage and self-annealing were performed on Hamamatsu SiPMs using a calibrated Am–Be neutron source from the Jefferson Lab Radiation Control group. As the result of irradiation both dark current and dark rate increase linearly as a function of the 1 MeV equivalent neutron fluence and a temperature dependent self-annealing effect is observed

  8. Acoustic radiation patterns for a source in a hard-walled unflanged circular duct

    NASA Technical Reports Server (NTRS)

    Holm, R. G.

    1973-01-01

    Acoustic radiation patterns are measured over a 320 deg arc for a point source in a finite length, hard walled, unflanged circular duct. The measured results are compared with computed results which are based on the Wiener-Hopf solution for radiation from a semi-infinite unflanged duct. Measurements and computations are presented for frequencies slightly below and slightly above each of the first four higher order radial mode cutoff frequencies. It is found that the computed and measured patterns show better agreement below the mode cut-off frequencies than above and that the agreement is better at lower frequencies that at higher frequencies. The computed radiation patterns do not show fine lobes which are caused by diffraction from the back end of the duct.

  9. Nanophosphor composite scintillator with a liquid matrix

    DOEpatents

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

    2010-03-16

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

  10. Radiation background in a LaBr3(Ce) gamma-ray scintillation detector.

    PubMed

    Rosson, Robert; Lahr, Jeffrey; Kahn, Bernd

    2011-12-01

    Gamma-ray spectral analyses with a 5-cm × 5-cm LaBr3(Ce) detector and a NaI(Tl) detector of the same size show that the LaBr3(Ce) has much better gamma-ray peak resolution and full-energy peak counting efficiency but worse detection sensitivity. The LaBr3(Ce) detector has relatively high intrinsic radiation background due to the naturally occurring La radioisotope in lanthanum. Although this La background is entirely below the energy of 1,500 keV, additional background is in the energy region between 1,500 keV and 2,750 keV. The manufacturer attributes this radiation to alpha particles emitted by the five short-lived progeny of an Ac impurity. Comparative values for peak resolution, full-energy peak counting efficiency, and detection sensitivity are reported for Am, Co, and Cs. Results of counting Cs sources at two activity levels demonstrate the impact of background on detection sensitivity.

  11. Boron loaded scintillator

    DOEpatents

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

    2009-10-20

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

  12. Radiation damage studies for the SDC electromagnetic calorimeter

    NASA Astrophysics Data System (ADS)

    Fazely, A. R.; Gunasingha, R.; Imlay, R. L.; Khosravi, E. S.; Lim, Jit-Ning; Lyndon, C.; McMills, G.; McNeil, R. R.; Metcalf, W. J.; Courtney, J. C.; Tashakkori, R.; Vegara, B. J.

    1993-01-01

    We report the results from a year long study aimed at radiation resistance and optical performance of scintillator tile with green wave shifter fiber readout. A careful investigation of several rad-hard plastic scintillators from Bicron and Kuraray, studies indicate that for a specific rad-hard Bicron scintillator, it is possible to build a tile/fiber EM calorimeter that can operate in the design luminosity of SSC. This calorimeter with excellent optical response would only have a light loss of about 5% after being exposed to 1 Mrad.

  13. A New Radiation Hard Semiconductor — Semi-Insulating GaN: Photoelectric Properties

    NASA Astrophysics Data System (ADS)

    Vaitkus, J.; Gaubas, E.; Kazukauskas, V.; Blue, A.; Cunningham, W.; Rahman, M.; Smith, K.; Sakai, S.

    2005-06-01

    The anticipated upgrade of the CERN Large Hadron Collider to ten times brighter luminosity poses a severe challenge to semiconductor detectors in the CERN experiments. The suitability of semi-insulating GaN (SI-GaN), proposed as an alternative to silicon for the fabrication of radiation hard detectors, is investigated here in MOCVD GaN layers grown on sapphire. The electrical properties of SI-GaN were studied by dc and microwave techniques, and defect parameters determined by the method of thermally stimulated currents. Variations of charge collection efficiency (CCE) in SI-GaN diodes induced by ionizing radiation of 5.48 MeV alpha particles were revealed. Samples were also irradiated by X-rays, reactor neutrons and high-energy proton fluences of up to 1016 cm-2. The high radiation hardness of SI-GaN was demonstrated by the modest reduction in CCE, from 92% to 77%, in the material irradiated by neutrons (up to a fluence of 1015 cm-2). The CCE was unaffected by an X-rays dose of 600 MRad), but decreased to a few % after proton and neutron fluences of 1016 cm-2. The electrical characteristics vary more significantly, depending on irradiation type and dose. Fast decay components and a significant role of percolation effects are observed in the photoconductivity transients.

  14. Scintillator materials containing lanthanum fluorides

    DOEpatents

    Moses, William W.

    1991-01-01

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

  15. Tests of HPGe- and scintillation-based backpack γ-radiation survey systems.

    PubMed

    Nilsson, Jonas M C; Östlund, Karl; Söderberg, Joakim; Mattsson, Sören; Rääf, Christopher

    2014-09-01

    The performance of three different backpack-mounted γ-radiation survey systems has been investigated. The systems are based on a LaBr3:Ce detector and a NaI(Tl) detector both with active volume dimensions of 76.2 mm in diameter and 76.2 mm length and a 123% relative efficiency HPGe detector. The detection limits of the systems were tested in a controlled outdoor environment in Sweden, followed by field tests of the HPGe- and LaBr3:Ce-based systems at the site of a radioactive waste repository in Georgia (in the Caucasus region of Eurasia). The results showed that the high efficiency HPGe detector performed significantly better than similar sized LaBr3:Ce and NaI(Tl) detectors, however, the HPGe detector was significantly heavier than the other systems. The use of different analysis methods revealed that creating maps of the survey area was the best method for offline analysis of survey data collected from a large area. Using off-site personnel for analysis of the data proved to be beneficial. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Foreign technology assessment: Environmental evaluation of a radiation-hard oscillator/divider

    NASA Astrophysics Data System (ADS)

    Dvorack, M. A.

    1993-03-01

    Salford Electrical Instruments, Ltd., and the General Electric Company's Hirst Research Center, under contract to the United Kingdom's (UK) Ministry of Defence, developed a radiation-hard, leadless chip-carrier-packaged oscillator/divider. Two preproduction clocks brought to Sandia National Laboratories (SNL) by a potential SNL customer underwent mechanical and thermal environmental evaluation. Because of the subsequent failure of one device and the deteriorating condition of another device, the devices were not subjected to radiation tests. The specifics of the environmental evaluation performed on these two clocks and the postmortem analysis of one unit, which ultimately failed, are described. Clock startup time versus temperature studies were also performed and compared to an SNL-designed clock having the same fundamental frequency.

  17. The role of radiation hard solar cells in minimizing the costs of global satellite communications systems

    NASA Technical Reports Server (NTRS)

    Summers, Geoffrey P.; Walters, Robert J.; Messenger, Scott R.; Burke, Edward A.

    1995-01-01

    An analysis embodied in a PC computer program is presented which quantitatively demonstrates how the availability of radiation hard solar cells can minimize the cost of a global satellite communication system. The chief distinction between the currently proposed systems, such as Iridium Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation within the earth's radiation belts can reduce the total system cost by as much as a factor of two, so long as radiation hard components including solar cells, can be used. A detailed evaluation of several types of planar solar cells is given, including commercially available Si and GaAs/Ge cells, and InP/Si cells which are under development. The computer program calculates the end of life (EOL) power density of solar arrays taking into account the cell geometry, coverglass thickness, support frame, electrical interconnects, etc. The EOL power density can be determined for any altitude from low earth orbit (LEO) to geosynchronous (GEO) and for equatorial to polar planes of inclination. The mission duration can be varied over the entire range planned for the proposed satellite systems. An algorithm is included in the program for determining the degradation of cell efficiency for different cell technologies due to proton and electron irradiation. The program can be used to determine the optimum configuration for any cell technology for a particular orbit and for a specified mission life. Several examples of applying the program are presented, in which it is shown that the EOL power density of different technologies can vary by an order of magnitude for certain missions. Therefore, although a relatively radiation soft technology can be made to provide the required EOL power by simply increasing the size of the array, the impact on the total system budget could be unacceptable, due to increased launch and

  18. The role of radiation hard solar cells in minimizing the costs of global satellite communications systems

    NASA Technical Reports Server (NTRS)

    Summers, Geoffrey P.; Walters, Robert J.; Messenger, Scott R.; Burke, Edward A.

    1995-01-01

    An analysis embodied in a PC computer program is presented which quantitatively demonstrates how the availability of radiation hard solar cells can minimize the cost of a global satellite communication system. The chief distinction between the currently proposed systems, such as Iridium Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation within the earth's radiation belts can reduce the total system cost by as much as a factor of two, so long as radiation hard components including solar cells, can be used. A detailed evaluation of several types of planar solar cells is given, including commercially available Si and GaAs/Ge cells, and InP/Si cells which are under development. The computer program calculates the end of life (EOL) power density of solar arrays taking into account the cell geometry, coverglass thickness, support frame, electrical interconnects, etc. The EOL power density can be determined for any altitude from low earth orbit (LEO) to geosynchronous (GEO) and for equatorial to polar planes of inclination. The mission duration can be varied over the entire range planned for the proposed satellite systems. An algorithm is included in the program for determining the degradation of cell efficiency for different cell technologies due to proton and electron irradiation. The program can be used to determine the optimum configuration for any cell technology for a particular orbit and for a specified mission life. Several examples of applying the program are presented, in which it is shown that the EOL power density of different technologies can vary by an order of magnitude for certain missions. Therefore, although a relatively radiation soft technology can be made to provide the required EOL power by simply increasing the size of the array, the impact on the total system budget could be unacceptable, due to increased launch and

  19. High-symmetry organic scintillator systems

    DOEpatents

    Feng, Patrick L.

    2017-06-14

    An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

  20. High-symmetry organic scintillator systems

    DOEpatents

    Feng, Patrick L.

    2017-09-05

    An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

  1. High-symmetry organic scintillator systems

    DOEpatents

    Feng, Patrick L.

    2017-07-18

    An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

  2. Development of new Polysiloxane Based Liquid Scintillators

    SciTech Connect

    Dalla Palma, M.; Quaranta, A.; Gramegna, F.; Marchi, T.; Cinausero, M.; Carturan, S.; Collazuol, G.; Checchia, C.; Degerlier, M.

    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

  3. Scintillator plate calorimetry

    SciTech Connect

    Price, L.E.

    1990-01-01

    Calorimetry using scintillator plates or tiles alternated with sheets of (usually heavy) passive absorber has been proven over multiple generations of collider detectors. Recent detectors including UA1, CDF, and ZEUS have shown good results from such calorimeters. The advantages offered by scintillator calorimetry for the SSC environment, in particular, are speed (<10 nsec), excellent energy resolution, low noise, and ease of achieving compensation and hence linearity. On the negative side of the ledger can be placed the historical sensitivity of plastic scintillators to radiation damage, the possibility of nonuniform response because of light attenuation, and the presence of cracks for light collection via wavelength shifting plastic (traditionally in sheet form). This approach to calorimetry is being investigated for SSC use by a collaboration of Ames Laboratory/Iowa State University, Argonne National Laboratory, Bicron Corporation, Florida State University, Louisiana State University, University of Mississippi, Oak Ridge National Laboratory, Virginia Polytechnic Institute and State University, Westinghouse Electric Corporation, and University of Wisconsin.

  4. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Low-threshold generation of harmonics and hard x radiation in a laser plasma. 1. Single-peak generation

    NASA Astrophysics Data System (ADS)

    Apollonov, V. V.; Derzhavin, S. I.; Kazakov, K. Kh

    1993-02-01

    A source of hard x radiation based on a laser plasma has been studied under conditions such that parametric instabilities are driven in the plasma at low intensities of the pump radiation (below 10 GW/cm2). A qualitative interpretation of the observed effects is offered.

  5. Radiation damage effects in Si materials and detectors and rad-hard Si detectors for SLHC

    NASA Astrophysics Data System (ADS)

    Li, Z.

    2009-03-01

    Silicon sensors, widely used in high energy and nuclear physics experiments, suffer severe radiation damage that leads to degradations in sensor performance. These degradations include significant increases in leakage current, bulk resistivity, space charge concentration, and free carrier trapping. For LHC applications, where the total fluence is in the order of 1 × 1015 neq/cm2 for 10 years, the increase in space charge concentration has been the main problem since it can significantly increase the sensor full depletion voltage, causing either breakdown if operated at high biases or charge collection loss if operated at lower biases than full depletion. For LHC Upgrade, or the SLHC, however, whit an increased total fluence up to 1 × 1016 neq/cm2, the main limiting factor for Si detector operation is the severe trapping of free carriers by radiation-induced defect levels. Several new approaches have been developed to make Si detector more radiation hard/tolerant to such ultra-high radiation, including 3D Si detectors, Current-Injected-Diodes (CID) detectors, and Elevated temperature annealing.

  6. Organic liquid scintillation detectors for on-the-fly neutron/gamma alarming and radionuclide identification in a pedestrian radiation portal monitor

    NASA Astrophysics Data System (ADS)

    Paff, Marc Gerrit; Ruch, Marc L.; Poitrasson-Riviere, Alexis; Sagadevan, Athena; Clarke, Shaun D.; Pozzi, Sara

    2015-07-01

    We present new experimental results from a radiation portal monitor based on the use of organic liquid scintillators. The system was tested as part of a 3He-free radiation portal monitor testing campaign at the European Commission's Joint Research Centre in Ispra, Italy, in February 2014. The radiation portal monitor was subjected to a wide range of test conditions described in ANSI N42.35, including a variety of gamma-ray sources and a 20,000 n/s 252Cf source. A false alarm test tested whether radiation portal monitors ever alarmed in the presence of only natural background. The University of Michigan Detection for Nuclear Nonproliferation Group's system triggered zero false alarms in 2739 trials. It consistently alarmed on a variety of gamma-ray sources travelling at 1.2 m/s at a 70 cm source to detector distance. The neutron source was detected at speeds up to 3 m/s and in configurations with up to 8 cm of high density polyethylene shielding. The success of on-the-fly radionuclide identification varied with the gamma-ray source measured as well as with which of two radionuclide identification methods was used. Both methods used a least squares comparison between the measured pulse height distributions to library spectra to pick the best match. The methods varied in how the pulse height distributions were modified prior to the least squares comparison. Correct identification rates were as high as 100% for highly enriched uranium, but as low as 50% for 241Am. Both radionuclide identification algorithms produced mixed results, but the concept of using liquid scintillation detectors for gamma-ray and neutron alarming in radiation portal monitor was validated.

  7. CdTe Timepix detectors for single-photon spectroscopy and linear polarimetry of high-flux hard x-ray radiation.

    PubMed

    Hahn, C; Weber, G; Märtin, R; Höfer, S; Kämpfer, T; Stöhlker, Th

    2016-04-01

    Single-photon spectroscopy of pulsed, high-intensity sources of hard X-rays - such as laser-generated plasmas - is often hampered by the pileup of several photons absorbed by the unsegmented, large-volume sensors routinely used for the detection of high-energy radiation. Detectors based on the Timepix chip, with a segmentation pitch of 55 μm and the possibility to be equipped with high-Z sensor chips, constitute an attractive alternative to commonly used passive solutions such as image plates. In this report, we present energy calibration and characterization measurements of such devices. The achievable energy resolution is comparable to that of scintillators for γ spectroscopy. Moreover, we also introduce a simple two-detector Compton polarimeter setup with a polarimeter quality of (98 ± 1)%. Finally, a proof-of-principle polarimetry experiment is discussed, where we studied the linear polarization of bremsstrahlung emitted by a laser-driven plasma and found an indication of the X-ray polarization direction depending on the polarization state of the incident laser pulse.

  8. CdTe Timepix detectors for single-photon spectroscopy and linear polarimetry of high-flux hard x-ray radiation

    SciTech Connect

    Hahn, C. Höfer, S.; Kämpfer, T.; Weber, G.; Märtin, R.; Stöhlker, Th.

    2016-04-15

    Single-photon spectroscopy of pulsed, high-intensity sources of hard X-rays — such as laser-generated plasmas — is often hampered by the pileup of several photons absorbed by the unsegmented, large-volume sensors routinely used for the detection of high-energy radiation. Detectors based on the Timepix chip, with a segmentation pitch of 55 μm and the possibility to be equipped with high-Z sensor chips, constitute an attractive alternative to commonly used passive solutions such as image plates. In this report, we present energy calibration and characterization measurements of such devices. The achievable energy resolution is comparable to that of scintillators for γ spectroscopy. Moreover, we also introduce a simple two-detector Compton polarimeter setup with a polarimeter quality of (98 ± 1)%. Finally, a proof-of-principle polarimetry experiment is discussed, where we studied the linear polarization of bremsstrahlung emitted by a laser-driven plasma and found an indication of the X-ray polarization direction depending on the polarization state of the incident laser pulse.

  9. Performance of radiation-hard HV/HR CMOS sensors for the ATLAS inner detector upgrades

    NASA Astrophysics Data System (ADS)

    Liu, J.; Barbero, M.; Bilbao De Mendizabal, J.; Breugnon, P.; Godiot-Basolo, S.; Pangaud, P.; Rozanov, A.

    2016-03-01

    A major upgrade (Phase II Upgrade) to the Large Hadron Collider (LHC), scheduled for 2022, will be brought to the machine so as to extend its discovery potential. The upgraded LHC, called High-Luminosity LHC (HL-LHC), will run with a nominal leveled instantaneous luminosity of 5×1034 cm-2s-1, more than twice the expected luminosity. This unprecedented luminosity will result in higher occupancy and background radiations, which will request the design of a new Inner Tracker (ITk) which should have higher granularity, reduced material budget and improved radiation tolerance. A new pixel sensor concept based on High Voltage and High Resistivity CMOS (HV/HR CMOS) technology targeting the ATLAS inner detector upgrade is under exploration. With respect to the traditional hybrid pixel detector, the HV/HR CMOS sensor can potentially offer lower material budget, reduced pixel pitch and lower cost. Several prototypes have been designed and characterized within the ATLAS upgrade R&D effort, to investigate the detection and radiation hardness performance of various commercial technologies. An overview of the HV/HR CMOS sensor operation principle is described in this paper. The characterizations of three prototypes with X-ray, proton and neutron irradiation are also given.

  10. X-ray silicon detectors for measuring hard x-ray radiation damage effects

    NASA Astrophysics Data System (ADS)

    Wagner, Delia; Halmagean, Eugenia T.; Loukas, Dido Y.; Misiakos, K.; Tsoi, Elisabeth; Veron, A.; Ohanisian, M.

    1997-07-01

    For high sensitivity hard x-ray detector applications there is a solid-state alternative using high purity silicon as starting material. The paper presents some original results concerning a radiation hardened technology to be used for obtaining x-ray silicon detectors and the behavior of the special designed devices in a specific radiation environment. Original processing sequences were experimentally tested and results concerning the most performant technology suited for this specific application are presented. Specially designed gettering steps were applied by backside ion implantation and annealing for enhancing the minority carriers lifetime in the substrate material and for reducing leakage currents at orders less than 10 nA. After a complete presentation of the specific characteristics of the as obtained detectors, they were exposed and completely characterized in x-ray ambient up to dose levels of 10(superscript 8) rad (E greater than 50 keV). Solutions for increasing the detector sensitivity and stability in radiation environments are proposed.

  11. Radiation-hard beam position detector for use in the accelerator dump lines

    SciTech Connect

    Pavel Degtiarenko; Danny Dotson; Arne Freyberger; Vladimir Popov

    2005-06-01

    A new method of beam position measurement suitable for monitoring high energy and high power charged particle beams in the vicinity of high power beam dumps is presented. We have found that a plate made of Chemical Vapor Deposition (CVD) Silicon Carbide (SiC) has physical properties that make it suitable for such an application. CVD SiC material is a chemically inert, extremely radiation-hard, thermo-resistive semiconductor capable of withstanding working temperatures over 1500 C. It has good thermal conductivity comparable to that of Aluminum, which makes it possible to use it in high-current particle beams. High electrical resistivity of the material, and its semiconductor properties allow characterization of the position of a particle beam crossing such a plate by measuring the balance of electrical currents at the plate ends. The design of a test device, and first results are presented in the report.

  12. The CERN RD50 Collaboration: Development of Radiation-Hard Semiconductor Detectors for Super-LHC

    SciTech Connect

    Macchiolo, Anna

    2005-10-12

    The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN represents a technological challenge for the vertex detectors of the SLHC experiments since the innermost layers will receive fast hadron fluences up to 1016 cm-2. The CERN RD50 project has been established to explore detector materials and designs that will allow to operate devices up to this limit. Among the different research lines followed by RD50 we report on the development of sensors produced with substrates like Czochralski and epitaxial silicon and on the investigation of the radiation hardness of p-type silicon detectors. Moreover innovative designs like thin, 3D and 3D-STC sensors are under evaluation in the RD50 Collaboration.

  13. Radiation hard mode-locked laser suitable as a spaceborne frequency comb.

    PubMed

    Buchs, Gilles; Kundermann, Stefan; Portuondo-Campa, Erwin; Lecomte, Steve

    2015-04-20

    We report ground-level gamma and proton radiation tests of a passively mode-locked diode-pumped solid-state laser (DPSSL) with Yb:KYW gain medium. A total gamma dose of 170 krad(H(2)O) applied in 5 days generates minor changes in performances while maintaining solitonic regime. Pre-irradiation specifications are fully recovered over a day to a few weeks timescale. A proton fluence of 9.76·10(10) cm(-2) applied in few minutes shows no alteration of the laser performances. Furthermore, complete stabilization of the laser shows excellent noise properties. From our results, we claim that the investigated femtosecond DPSSL technology can be considered rad-hard and would be suitable for generating frequency combs compatible with long duration space missions.

  14. Development of radiation hard CMOS active pixel sensors for HL-LHC

    NASA Astrophysics Data System (ADS)

    Pernegger, Heinz

    2016-07-01

    New pixel detectors, based on commercial high voltage and/or high resistivity full CMOS processes, hold promise as next-generation active pixel sensors for inner and intermediate layers of the upgraded ATLAS tracker. The use of commercial CMOS processes allow cost-effective detector construction and simpler hybridisation techniques. The paper gives an overview of the results obtained on AMS-produced CMOS sensors coupled to the ATLAS Pixel FE-I4 readout chips. The SOI (silicon-on-insulator) produced sensors by XFAB hold great promise as radiation hard SOI-CMOS sensors due to their combination of partially depleted SOI transistors reducing back-gate effects. The test results include pre-/post-irradiation comparison, measurements of charge collection regions as well as test beam results.

  15. SBIR Final Report. Liquid Core Optical Scintillating Fibers

    SciTech Connect

    Beetz, C.P.; Steinbeck, J.; Buerstler, R.

    2000-05-16

    This Phase I SBIR project focused on developing flexible scintillating liquid core optical fibers, with potential uses in high-energy calorimetry, tracking, preradiators, active targets or other fast detectors. Progress on the six tasks of the project is summarized. The technical developments involve three technology components: (1) highly flexible capillaries or tubes of relatively low n (index of refraction) to serve as cladding and liquid core containment; (2) scintillator (and clear) fluids of relatively high n to serve as a core-- these fluids must have a high light transmission and, for some applications, radiation hardness; (3) optical end plugs, plug insertion, and plug-cladding tube sealing technology to contain the core fluids in the tubes, and to transmit the light.

  16. First tests of a novel radiation hard CMOS sensor process for Depleted Monolithic Active Pixel Sensors

    NASA Astrophysics Data System (ADS)

    Pernegger, H.; Bates, R.; Buttar, C.; Dalla, M.; van Hoorne, J. W.; Kugathasan, T.; Maneuski, D.; Musa, L.; Riedler, P.; Riegel, C.; Sbarra, C.; Schaefer, D.; Schioppa, E. J.; Snoeys, W.

    2017-06-01

    The upgrade of the ATLAS [1] tracking detector for the High-Luminosity Large Hadron Collider (LHC) at CERN requires novel radiation hard silicon sensor technologies. Significant effort has been put into the development of monolithic CMOS sensors but it has been a challenge to combine a low capacitance of the sensing node with full depletion of the sensitive layer. Low capacitance brings low analog power. Depletion of the sensitive layer causes the signal charge to be collected by drift sufficiently fast to separate hits from consecutive bunch crossings (25 ns at the LHC) and to avoid losing the charge by trapping. This paper focuses on the characterization of charge collection properties and detection efficiency of prototype sensors originally designed in the framework of the ALICE Inner Tracking System (ITS) upgrade [2]. The prototypes are fabricated both in the standard TowerJazz 180nm CMOS imager process [3] and in an innovative modification of this process developed in collaboration with the foundry, aimed to fully deplete the sensitive epitaxial layer and enhance the tolerance to non-ionizing energy loss. Sensors fabricated in standard and modified process variants were characterized using radioactive sources, focused X-ray beam and test beams before and after irradiation. Contrary to sensors manufactured in the standard process, sensors from the modified process remain fully functional even after a dose of 1015neq/cm2, which is the the expected NIEL radiation fluence for the outer pixel layers in the future ATLAS Inner Tracker (ITk) [4].

  17. Radiation Hardness tests with neutron flux on different Silicon photomultiplier devices

    NASA Astrophysics Data System (ADS)

    Cattaneo, P. W.; Cervi, T.; Menegolli, A.; Oddone, M.; Prata, M.; Prata, M. C.; Rossella, M.

    2017-07-01

    Radiation hardness is an important requirement for solid state readout devices operating in high radiation environments common in particle physics experiments. The MEG II experiment, at PSI, Switzerland, investigates the forbidden decay μ+ → e+ γ. Exploiting the most intense muon beam of the world. A significant flux of non-thermal neutrons (kinetic energy Ek>= 0.5 MeV) is present in the experimental hall produced along the beam-line and in the hall itself. We present the effects of neutron fluxes comparable to the MEG II expected doses on several Silicon Photomultiplier (SiPMs). The tested models are: AdvanSiD ASD-NUV3S-P50 (used in MEG II experiment), AdvanSiD ASD-NUV3S-P40, AdvanSiD ASD-RGB3S-P40, Hamamatsu and Excelitas C30742-33-050-X. The neutron source is the thermal Sub-critical Multiplication complex (SM1) moderated with water, located at the University of Pavia (Italy). We report the change of SiPMs most important electric parameters: dark current, dark pulse frequency, gain, direct bias resistance, as a function of the integrated neutron fluency.

  18. Decision feedback equalization for radiation hard data link at 5 Gbps

    NASA Astrophysics Data System (ADS)

    Wallängen, V.; Garcia-Sciveres, M.

    2017-01-01

    The increased particle collision rate following the upgrade of the Large Hadron Collider (LHC) to an increased luminosity requires an increased readout data speed, especially for the ATLAS pixel detector, located closest to the particle interaction point. For this reason, during the Phase-II upgrade of the ATLAS experiment the output data speed of the pixel front-end chips will be increased from 160 Mbps to 5 Gbps. The increased radiation levels will require a radiation hard data transmission link to be designed to carry this data from the pixel front-end to the off-detector system where it will undergo optical conversion. We propose a receiver utilizing the concept of Decision Feedback Equalization (DFE) to be used in this link, where the number of filter taps can be determined from simulations using S-parameter data from measurements of various customized cable prototypes under characterization as candidates to function as transmission medium between the on-chip data driver and the receiver of the link. A dedicated framework has been set up in Matlab to analyze the S-parameter characteristics for the various cable prototypes and investigate the possibilities for signal recovery and maintained signal integrity using DFE, as well as pre-emphasis and different encoding schemes. The simulation results indicate that DFE could be an excellent choice for expanding the system bandwidth to reach required data speeds with minimal signal distortion.

  19. Radiation hardness of semiconductor avalanche detectors for calorimeters in future HEP experiments

    NASA Astrophysics Data System (ADS)

    Kushpil, V.; Mikhaylov, V.; Kugler, A.; Kushpil, S.; Ladygin, V. P.; Svoboda, O.; Tlustý, P.

    2016-02-01

    During the last years, semiconductor avalanche detectors are being widely used as the replacement of classical PMTs in calorimeters for many HEP experiments. In this report, basic selection criteria for replacement of PMTs by solid state devices and specific problems in the investigation of detectors radiation hardness are discussed. The design and performance of the hadron calorimeters developed for the future high energy nuclear physics experiments at FAIR, NICA, and CERN are discussed. The Projectile Spectator Detector (PSD) for the CBM experiment at the future FAIR facility, the Forward Calorimeter for the NA61 experiment at CERN and the Multi Purpose Detector at the future NICA facility are reviewed. Moreover, new methods of data analysis and results interpretation for radiation experiments are described. Specific problems of development of detectors control systems and possibilities of reliability improvement of multi-channel detectors systems are shortly overviewed. All experimental material is based on the investigation of SiPM and MPPC at the neutron source in NPI Rez.

  20. High Speed, Radiation Hard CMOS Pixel Sensors for Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Contarato, Devis; Denes, Peter; Doering, Dionisio; Joseph, John; Krieger, Brad

    CMOS monolithic active pixel sensors are currently being established as the technology of choice for new generation digital imaging systems in Transmission Electron Microscopy (TEM). A careful sensor design that couples μm-level pixel pitches with high frame rate readout and radiation hardness to very high electron doses enables the fabrication of direct electron detectors that are quickly revolutionizing high-resolution TEM imaging in material science and molecular biology. This paper will review the principal characteristics of this novel technology and its advantages over conventional, optically-coupled cameras, and retrace the sensor development driven by the Transmission Electron Aberration corrected Microscope (TEAM) project at the LBNL National Center for Electron Microscopy (NCEM), illustrating in particular the imaging capabilities enabled by single electron detection at high frame rate. Further, the presentation will report on the translation of the TEAM technology to a finer feature size process, resulting in a sensor with higher spatial resolution and superior radiation tolerance currently serving as the baseline for a commercial camera system.

  1. Single-Event Gate Rupture in Power MOSFETs: A New Radiation Hardness Assurance Approach

    NASA Technical Reports Server (NTRS)

    Lauenstein, Jean-Marie

    2011-01-01

    Almost every space mission uses vertical power metal-semiconductor-oxide field-effect transistors (MOSFETs) in its power-supply circuitry. These devices can fail catastrophically due to single-event gate rupture (SEGR) when exposed to energetic heavy ions. To reduce SEGR failure risk, the off-state operating voltages of the devices are derated based upon radiation tests at heavy-ion accelerator facilities. Testing is very expensive. Even so, data from these tests provide only a limited guide to on-orbit performance. In this work, a device simulation-based method is developed to measure the response to strikes from heavy ions unavailable at accelerator facilities but posing potential risk on orbit. This work is the first to show that the present derating factor, which was established from non-radiation reliability concerns, is appropriate to reduce on-orbit SEGR failure risk when applied to data acquired from ions with appropriate penetration range. A second important outcome of this study is the demonstration of the capability and usefulness of this simulation technique for augmenting SEGR data from accelerator beam facilities. The mechanisms of SEGR are two-fold: the gate oxide is weakened by the passage of the ion through it, and the charge ionized along the ion track in the silicon transiently increases the oxide electric field. Most hardness assurance methodologies consider the latter mechanism only. This work demonstrates through experiment and simulation that the gate oxide response should not be neglected. In addition, the premise that the temporary weakening of the oxide due to the ion interaction with it, as opposed to due to the transient oxide field generated from within the silicon, is validated. Based upon these findings, a new approach to radiation hardness assurance for SEGR in power MOSFETs is defined to reduce SEGR risk in space flight projects. Finally, the potential impact of accumulated dose over the course of a space mission on SEGR

  2. Radiation hardness studies of n + -in-n planar pixel sensors for the ATLAS upgrades

    NASA Astrophysics Data System (ADS)

    Altenheiner, S.; Goessling, C.; Jentzsch, J.; Klingenberg, R.; Muenstermann, D.; Rummler, A.; Troska, G.; Wittig, T.

    2011-12-01

    The ATLAS experiment at the LHC is planning upgrades of its pixel detector to cope with the luminosity increase foreseen in the coming years within the transition from LHC to Super-LHC (SLHC/HL-LHC). Associated with the increase in instantaneous luminosity is a rise of the target integrated luminosity from 730 to about 3000 fb -1 which directly translates into significantly higher radiation damage. These upgrades consist of the installation of a 4th pixel layer, the insertable b-layer IBL, with a mean sensor radius of only 32 mm from the beam axis, before 2016/17. In addition, the complete pixel detector will be exchanged before 2020/21. Being very close to the beam, the radiation damage of the IBL sensors might be as high as 5×1015 neq cm-2 at their end-of-life. The total fluence of the innermost pixel layer after the SLHC upgrade might even reach 2×1016 neq cm-2. To investigate the radiation hardness and suitability of the current ATLAS pixel sensors for these fluences, n +-in-n silicon pixel sensors from the ATLAS Pixel production have been irradiated by reactor neutrons to the IBL design fluence and been tested with pions at the SPS and with electrons from a 90Sr source in the laboratory. The collected charge after IBL fluences was found to exceed 10 000 electrons per MIP at 1 kV of bias voltage which is in agreement with data collected with strip sensors. After SLHC fluences, still reliable operation of the devices could be observed with a collected charge of more than 5000 electrons per MIP.

  3. Irradiation of thin diamond detectors and radiation hardness tests using MeV protons

    NASA Astrophysics Data System (ADS)

    Grilj, V.; Skukan, N.; Jakšić, M.; Kada, W.; Kamiya, T.

    2013-07-01

    Although numerous studies have confirmed the superb radiation hardness of diamond for high-energy (above 100 MeV) protons, almost no data have been reported in the MeV energy range. Because the interaction mechanism that dominates the displacement damage cross section is different for these two energy regimes, it could be misleading to simply extrapolate the results of previous papers down to low energies. Therefore, the radiation tolerance of a 50 μm thick single-crystal CVD diamond detector was tested by irradiating it with 4.5 MeV protons. The scanning microbeam allowed for the selective introduction of damage to a small area of the detector. The ion beam-induced current (IBIC) was used to monitor the charge collection efficiency (CCE) degradation due to the electrically active defects produced. The irradiation was stopped when a signal degradation of nearly 3% was observed. For comparison, the procedure was repeated on a 50 μm thick silicon surface barrier detector (SSBD), for which a significantly higher proton fluence was required to reach the same signal decrease as in the diamond detector. This result can be explained by the different recombination rates of the vacancies and interstitials created in the two materials. The transport properties of electrons and holes in the damaged and virgin areas of the diamond detector were also investigated by 500 keV protons and 6 MeV carbon ions as short-range IBIC probes. The mobility-lifetime products calculated for both charge carriers after fitting the single-carrier Hecht equation indicated that there was more pronounced electron trapping by the radiation-induced defects. The frequently reported effect of polarization in diamond was successfully avoided for 500 keV protons but still remained for 6 MeV carbon ions because an order of magnitude higher ionization rate.

  4. Improvements in apparatus and procedures for using an organic liquid scintillator as a fast-neutron spectrometer for radiation protection applications

    SciTech Connect

    Thorngate, J.H.

    1987-05-15

    For use in radiation protection measurements, a neutron spectrometer must have a wide energy range, good sensitivity, medium resolution, and ease of taking and reducing data. No single spectrometer meets all of these requirements. Several experiments aimed at improving and characterizing the detector response to gamma rays and neutrons were conducted. A light pipe (25 mm) was needed between the scintillator cell and the photomultiplier tube to achieve the best resolution. The light output of the scintillator as a function of gamma-ray energy was measured. Three experiments were conducted to determine the light output as a function of neutron energy. Monte Carlo calculations were made to evaluate the effects of multiple neutron scattering and edge effects in the detector. The electronic systems associated with the detector were improved with a transistorized circuit providing the bias voltage for the photomultiplier tube dynodes. This circuit was needed to obtain pulse-height linearity over the wide range of signal sizes. A special live-time clock was built to compensate for the large amount of dead time generated by the pulse-shape discrimination circuit we chose to use. 64 refs., 58 figs., 9 tabs.

  5. Radiation hardness of 30 cm long CsI(Tl) crystals

    NASA Astrophysics Data System (ADS)

    Longo, S.; Roney, J. M.

    2016-08-01

    Measurements of the degradation in performance of 30 cm long CsI(Tl) scintillation crystals exposed to 1 MeV photon doses of 2, 10, 35, 100 and 1000 Gy are presented. The light yield, light yield longitudinal non-uniformity, scintillation decay times, energy resolution and timing resolution of a set of spare crystals from the BABAR and Belle experiments are studied as a function of these doses. In addition, a model that describes the plateau observed in the light output loss as a function of dose in terms of increase in concentrations of absorption centres with irradiation is presented.

  6. Applications of Robust, Radiation Hard AlGaN Optoelectronic Devices in Space Exploration and High Energy Density Physics

    SciTech Connect

    Sun, K.

    2011-05-04

    This slide show presents: space exploration applications; high energy density physics applications; UV LED and photodiode radiation hardness; UV LED and photodiode space qualification; UV LED AC charge management; and UV LED satellite payload instruments. A UV LED satellite will be launched 2nd half 2012.

  7. First Tests of 6Li Doped Glass Scintillators for Ultracold Neutron Detection

    PubMed Central

    Ban, G.; Fléchard, X.; Labalme, M.; Lefort, T.; Liénard, E.; Naviliat-Cuncic, O.; Fierlinger, P.; Kirch, K.; Bodek, K.; Geltenbort, P.

    2005-01-01

    We report the results of test measurements aimed at determining the performances of 6Li doped glass scintillators for the detection of ultra-cold neutrons. Four types of scintillators, GS1, GS3, GS10 and GS20, which differ by their 6Li concentrations, have been tested. The signal to background separation is fully acceptable. The relative detection efficiencies have been determined as a function of the neutron velocity. We find that GS10 has a higher efficiency than the others for the detection of neutrons with velocities below 7 m/s. Two pieces of scintillators have been irradiated with a high flux of cold neutrons to test the radiation hardness of the glasses. No reduction in the pulse height has been observed up to an absorbed neutron dose of 1 × 1013 cm−3. PMID:27308137

  8. Unitary scintillation detector and system

    DOEpatents

    McElhaney, Stephanie A.; Chiles, Marion M.

    1994-01-01

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

  9. Unitary scintillation detector and system

    DOEpatents

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

    1994-05-31

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

  10. AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics

    SciTech Connect

    Sun, K. X.

    2011-05-31

    This presentation provides an overview of robust, radiation hard AlGaN optoelectronic devices and their applications in space exploration & high energy density physics. Particularly, deep UV LED and deep UV photodiodes are discussed with regard to their applications, radiation hardness and space qualification. AC charge management of UV LED satellite payload instruments, which were to be launched in late 2012, is covered.

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

    SciTech Connect

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

    2016-10-07

    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. Here, we show that the scaling with dose rate is consistent with that expected from diffusion effects.

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  13. Radiation damage effects in Y2SiO5:Ce scintillation crystals under γ-quanta and 24 GeV protons

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Borisevitch, A.; Gektin, A.; Gerasymov, Ia.; Korjik, M.; Kozlov, D.; Kurtsev, D.; Mechinsky, V.; Sidletskiy, O.; Zoueyski, R.

    2015-05-01

    This work focuses on the study of changes in the optical transmission of Y2SiO5:Ce crystals caused by ionizing radiation from γ-quanta and high energy protons. Radioisotope content of proton-irradiated crystals, transmission and induced absorption spectra, and scintillation characteristics are measured after irradiation with protons. In contrast to crystals of heavy complex oxides, Y2SiO5:Ce crystals do not demonstrate significant deterioration of transmission in the luminescence range (400-600 nm) under irradiation. Such crystals can be considered as a material for construction of detecting cells of the calorimetric detectors at LHC with high luminosity. The feasibility of growing large crackless Y2SiO5:Ce crystals with a diameter up to 50 mm and length up to 250 mm is demonstrated.

  14. Radiation-Hard SpaceWire/Gigabit Ethernet-Compatible Transponder

    NASA Technical Reports Server (NTRS)

    Katzman, Vladimir

    2012-01-01

    A radiation-hard transponder was developed utilizing submicron/nanotechnology from IBM. The device consumes low power and has a low fabrication cost. This device utilizes a Plug-and-Play concept, and can be integrated into intra-satellite networks, supporting SpaceWire and Gigabit Ethernet I/O. A space-qualified, 100-pin package also was developed, allowing space-qualified (class K) transponders to be delivered within a six-month time frame. The novel, optical, radiation-tolerant transponder was implemented as a standalone board, containing the transponder ASIC (application specific integrated circuit) and optical module, with an FPGA (field-programmable gate array) friendly parallel interface. It features improved radiation tolerance; high-data-rate, low-power consumption; and advanced functionality. The transponder utilizes a patented current mode logic library of radiation-hardened-by-architecture cells. The transponder was developed, fabricated, and radhard tested up to 1 MRad. It was fabricated using 90-nm CMOS (complementary metal oxide semiconductor) 9 SF process from IBM, and incorporates full BIT circuitry, allowing a loop back test. The low-speed parallel LVCMOS (lowvoltage complementary metal oxide semiconductor) bus is compatible with Actel FPGA. The output LVDS (low-voltage differential signaling) interface operates up to 1.5 Gb/s. Built-in CDR (clock-data recovery) circuitry provides robust synchronization and incorporates two alarm signals such as synch loss and signal loss. The ultra-linear peak detector scheme allows on-line control of the amplitude of the input signal. Power consumption is less than 300 mW. The developed transponder with a 1.25 Gb/s serial data rate incorporates a 10-to-1 serializer with an internal clock multiplication unit and a 10-1 deserializer with internal clock and data recovery block, which can operate with 8B10B encoded signals. Three loop-back test modes are provided to facilitate the built-in-test functionality. The

  15. Study of GSO scintillator for the LHCf upgrade

    SciTech Connect

    Kawade, K.; Fukatsu, K.; Itow, Y.; Mase, T.; Masuda, K.; Matsubara, Y.; Mitsuka, G.; Sako, T.; Suzuki, K.; Taki, K.; Suzuki, T.; Kasahara, K.; Nakai, M.; Torii, S.; Adriani, O.; Bonechi, L.; D'Alessandro, R.; Bongi, M.; Menjo, H.; Papini, P.

    2011-09-22

    The GSO scintillator has a very excellent radiation resistance, fast decay time and large amounts of light yield. Because of these features, GSO will be used to upgrade the current LHCf detector. We examined the features of GSO by using heavy ion beam at Heavy Ion Medical Accelerator in Chiba (HIMAC) Japan. The linearity of PMT R7400 for the large light yield of GSO with a {sup 132}Xe beam and the radiation hardness with a {sup 12}C beam were measured. As a result, GSO scintillator showed a good linearity up to the signal corresponding to 6 TeV EM-shower maximum in the LHCf detector, and a good radiation hardness up to 7x10{sup 5} Gy. For the LHCf Arm1 detector, small scaled GSO crystals (GSO bars), have been fabricated for the position determination detector. 5 GSO bars have been manufactured and its performance have been evaluated using {sup 12}C beam. Its light yield and position dependency have been evaluated.

  16. Radiation Evaluation of an Advanced 64Mb 3.3V DRAM and Insights into the Effects of Scaling on Radiation Hardness

    NASA Technical Reports Server (NTRS)

    Shaw, D. C.; Swift, G. M.; Johnston, A. H.

    1995-01-01

    In this paper, total ionizing dose radiation evaluations of the Micron 64 Mb 3.3 V, fast page mode DRAM and the IBM LUNA-ES 16 Mb DRAM are presented. The effects of scaling on total ionizing dose radiation hardness are studied utilizing test structures and a series of 16 Mb DRAMs with different feature sizes from the same manufacturing line. General agreement was found between the threshold voltage shifts of 16 Mb DRAM test structures and the threshold voltage measured on complete circuits using retention time measurements. Retention time measurement data from early radiation doses are shown that allow internal failure modes to be distinguished.

  17. Radiation Evaluation of an Advanced 64Mb 3.3V DRAM and Insights into the Effects of Scaling on Radiation Hardness

    NASA Technical Reports Server (NTRS)

    Shaw, D. C.; Swift, G. M.; Johnston, A. H.

    1995-01-01

    In this paper, total ionizing dose radiation evaluations of the Micron 64 Mb 3.3 V, fast page mode DRAM and the IBM LUNA-ES 16 Mb DRAM are presented. The effects of scaling on total ionizing dose radiation hardness are studied utilizing test structures and a series of 16 Mb DRAMs with different feature sizes from the same manufacturing line. General agreement was found between the threshold voltage shifts of 16 Mb DRAM test structures and the threshold voltage measured on complete circuits using retention time measurements. Retention time measurement data from early radiation doses are shown that allow internal failure modes to be distinguished.

  18. Steady jets from radiatively efficient hard states in GRS 1915+105

    NASA Astrophysics Data System (ADS)

    Rushton, A.; Spencer, R.; Fender, R.; Pooley, G.

    2010-12-01

    Recent studies of different X-ray binaries (XRBs) have shown a clear correlation between the radio and X-ray emission. We present evidence of a close relationship found between the radio and X-ray emission at different epochs for GRS 1915+105, using observations from the Ryle Telescope and Rossi X-ray Timing Explorer satellite. The strongest correlation was found during the hard state (also known as the “plateau” state), where a steady AU-scale jet is known to exist. Both the radio and X-ray emission were found to decay from the start of most plateau states, with the radio emission decaying faster. An empirical relationship of Sradio ∝ SX-rayξ was then fitted to data taken only during the plateau state, resulting in a power-law index of ξ 1.7±0.3, which is significantly higher than in other black hole XRBs in a similar state. An advection-flow model was then fitted to this relationship and compared to the universal XRB relationship as described by Gallo et al. (2003, MNRAS, 344, 60). We conclude that either (I) the accretion disk in this source is radiatively efficient, even during the continuous outflow of a compact jet, which could also suggest a universal turn-over from radiatively inefficient to efficient for all stellar-mass black holes at a critical mass accretion rate (dot{m}{c} ≈ 1018.5 g/s); or (II) the X-rays in the plateau state are dominated by emission from the base of the jet and not the accretion disk (e.g. via inverse Compton scattering from the outflow).

  19. Mercury Chalcohalide Semiconductor Hg3Se2Br2 for Hard Radiation Detection

    DOE PAGES

    Li, Hao; Meng, Fang; Malliakas, Christos D.; ...

    2016-09-28

    We present Hg3Se2Br2 that has a wide band gap semiconductor (2.22 eV) with high density (7.598 g/cm3) and crystallizes in the monoclinic space group C2/m with cell parameters of a = 17.496 (4) Å, b = 9.3991 (19) Å, c = 9.776(2) Å, β = 90.46(3)°, V = 1607.6(6) Å3. It melts congruently at a low temperature, 566°C, which allows for an easy single crystal growth directly from the stoichiometric melt. Single crystals of Hg3Se2Br2 up to 1 cm long have been grown using the Bridgman method. Hg3Se2Br2 single crystals exhibit a strong photocurrent response when exposed to Ag X-raymore » and blue diode laser. The resistivity of Hg3Se2Br2 measured by the two probe method is on the order of 1011 Ω·cm, and the mobility-lifetime product (μτ) of the electron and hole carriers estimated from the energy spectroscopy under Ag X-ray radiation are (μτ)e ≈ 1.4 × 10–4cm2/V and (μτ)h ≈ 9.2 × 10–5cm2/V. Electronic structure calculations at the density functional theory level indicate a direct band gap and a relatively small effective mass for carriers. Lastly, on the basis of the photoconductivity and hard X-ray spectrum, Hg3Se2Br2 is a promising candidate for X-ray and γ-ray radiation detection at room temperature.« less

  20. Radiocarbon dating of archaeological samples (sambaqui) using CO(2) absorption and liquid scintillation spectrometry of low background radiation.

    PubMed

    Mendonça, Maria Lúcia T G; Godoy, José M; da Cruz, Rosana P; Perez, Rhoneds A R

    2006-01-01

    Sambaqui means, in the Tupi language, a hill of shells. The sambaquis are archaeological sites with remains of pre-historical Brazilian occupation. Since the sambaqui sites in the Rio de Janeiro state region are older than 10,000 years, the applicability of CO(2) absorption on Carbo-sorb and (14)C determination by counting on a low background liquid scintillation counter was tested. In the present work, sambaqui shells were treated with H(3)PO(4) in a closed vessel in order to generate CO(2). The produced CO(2) was absorbed on Carbo-sorb. On saturation about 0.6g of carbon, as CO(2), was mixed with commercial liquid scintillation cocktail (Permafluor), and the (14)C activity determined by counting on a low background counter, Packard Tricarb 3170 TR/SL, for a period of 1000 mins to enable detection of a radiocarbon age of 22,400 BP. But only samples with ages up to 3500 BP were submitted to the method because the samples had been collected in the municipality of Guapimirim, in archaeological sambaqui-type sites belonging to this age range. The same samples were sent to the (14)C Laboratory of the Centro de Energia Nuclear na Agricultura (CENA/USP) where similar results were obtained.

  1. Current status on plastic scintillators modifications

    SciTech Connect

    Hamel, Matthieu; Bertrand, Guillaume H.V.; Carrel, Frederick; Coulon, Romain; Dumazert, Jonathan; Montbarbon, Eva; Sguerra, Fabien

    2015-07-01

    Recent developments of plastic scintillators are reviewed, from 2000 to March 2015. All examples are distributed into the main purpose, i.e. the nature of the radionuclide provided with the scope of detection of various radiation particles. The main characteristics of these newly created scintillators and their detection properties are given. (authors)

  2. Pixel frontend electronics in a radiation hard technology for hybrid and monolithic applications

    SciTech Connect

    Pengg, F. |; Campbell, M.; Heijne, E.H.M.; Snoeys, W.

    1996-06-01

    Pixel detector readout cells have been designed in the radiation hard DMILL technology and their characteristics evaluated before and after irradiation to 14Mrad. The test chip consists of two blocks of six readout cells each. Two different charge amplifiers are implemented, one of them using a capacitive feedback loop, the other the fast signal charge transfer to a high impedance integrating node. The measured equivalent noise charge is 110e{sup {minus}}r.m.s. before and 150e{sup {minus}}r.m.s. after irradiation. With a discriminator threshold set to 5000e{sup {minus}}, which reduces for the same bias setting to 400e{sup {minus}} after irradiation, the threshold variation is 300e{sup {minus}}r.m.s. and 250e{sup {minus}}r.m.s. respectively. The time walk is 40ns before and after irradiation. The use of this SOI technology for monolithic integration of electronics and detector in one substrate is under investigation.

  3. Radiation Hard Bandpass Filters for Mid- to Far-IR Planetary Instruments

    NASA Technical Reports Server (NTRS)

    Brown, Ari D.; Aslam, Shahid; Chervenack, James A.; Huang, Wei-Chung; Merrell, Willie C.; Quijada, Manuel; Steptoe-Jackson, Rosalind; Wollack, Edward J.

    2012-01-01

    We present a novel method to fabricate compact metal mesh bandpass filters for use in mid- to far-infrared planetary instruments operating in the 20-600 micron wavelength spectral regime. Our target applications include thermal mapping instruments on ESA's JUICE as well as on a de-scoped JEO. These filters are novel because they are compact, customizable, free-standing copper mesh resonant bandpass filters with micromachined silicon support frames. The filters are well suited for thermal mapping mission to the outer planets and their moons because the filter material is radiation hard. Furthermore, the silicon support frame allows for effective hybridization with sensors made on silicon substrates. Using a Fourier Transform Spectrometer, we have demonstrated high transmittance within the passband as well as good out-of-band rejection [1]. In addition, we have developed a unique method of filter stacking in order to increase the bandwidth and sharpen the roll-off of the filters. This method allows one to reliably control the spacing between filters to within 2 microns. Furthermore, our method allows for reliable control over the relative position and orienta-tion between the shared faces of the filters.

  4. Divalent fluoride doped cerium fluoride scintillator

    DOEpatents

    Anderson, David F.; Sparrow, Robert W.

    1991-01-01

    The use of divalent fluoride dopants in scintillator materials comprising cerium fluoride is disclosed. The preferred divalent fluoride dopants are calcium fluoride, strontium fluoride, and barium fluoride. The preferred amount of divalent fluoride dopant is less than about two percent by weight of the total scintillator. Cerium fluoride scintillator crystals grown with the addition of a divalent fluoride have exhibited better transmissions and higher light outputs than crystals grown without the addition of such dopants. These scintillators are useful in radiation detection and monitoring applications, and are particularly well suited for high-rate applications such as positron emission tomography (PET).

  5. New Scintillators for Photosensitive Gaseous Detectors

    NASA Astrophysics Data System (ADS)

    Charpak, G.; Peskov, V.; Scigocki, D.; Valbis, J.

    A new family of scintillators are presented. Their properties are similar to those of barium fluoride, and the spectrum of the scintillation emission is between 140 and 300 nm. Our latest efficiency measurements of ethyl ferrocene and triethylamine liquid or caesium iodide solid photocathodes, in parallel-plate avalanche chambers (PPACs) at high electric field, are also presented. We discuss the revolutionary consequences of the combination of the new scintillators with PPACs with semitransparent photocathodes deposited on the crystals, such as high speed, high resistance to radiation damage, compacity, high gamma efficiency, and applications to tracking devices with scintillation optical fibres.

  6. WE-C-217BCD-11: Coupled Radiative and Optical Geant4 Simulation of MV EPIDs Based on Thick Pixelated Scintillating Crystals.

    PubMed

    Constantin, D; Sun, M; Abel, E; Star-Lack, J; Fahrig, R

    2012-06-01

    One way to greatly reduce the incidence of metal artifacts produced in kilovoltage (kV) CT images is by using megavoltage (MV) photons that penetrate high-Z objects, thus providing a measurable signal. For do se-efficient imaging, a high detective quantum efficiency (DQE) MV detector is desired. This study validates the coupled radiation and optical Geant4 simulation results against experimental data from various prototype pixelated scintillator MV detectors and determines the essential optical parameters which control the detector performance. Experimental data obtained with a 6MV radiation source from 8 different detectors was considered. The detectors used CsI, CdW and BGO as scintillating crystals and polystyrene septal wall material. Accurate Geant4 models of the detectors were implemented and coupled radiation and optical simulations were performed. The unknown optical properties of the models were determined by minimizing the difference between the modulation transfer functions (MTF) of the simulated data obtained with the slanted slit technique and the experimental MTFs. With the set of optical properties fixed, further simulation validation was performed against the experimental normalized noise power spectrum (NNPS(f)) and the experimental DQE(f) curves for each detector. All the simulations were performed on a computer cluster deployed on the Amazon EC2 platform. The optimal values for the free optical parameters are 10%, 95% and 90% for the top surface reflectivity, the crystal-sept a surface reflectivity, and the Lambertian component contribution to the reflected beam from the crystal-septa interface respectively. The absolute difference between experimental and simulated data was below 10% for all the data sets. To our knowledge this study is the first to present a full optical and radiative DQE(f) model using Geant4 that shows an excellent match with experimental data. The model indicates that improved performance can be obtained using more specular

  7. [Radiation screening test for commercial food products and foodstuffs for food services using NaI (Tl) scintillation survey meter].

    PubMed

    Kamimura, Masaru; Takanashi, Yoshimitsu; Kihara, Akiko; Tsutake, Toyoshige; Mitsui, Yoshio

    2013-01-01

    Screening tests were carried out for radioactive cesium in foods using a NaI (Tl) scintillation survey meter. The screening level was set at 250 Bq/kg, and specimens exceeding this level were scheduled to be sent to an external testing organization, which would conduct further tests using a germanium semiconductor detector. Some specimens that did not reach the screening level were also sent to the same organization. Foodstuffs used in commercial food products circulated in Chiba city were targeted, along with food services provided to schools and day care centers. In all, 495 specimens were tested; however, no specimens exceeded the screening level. The results of verification tests confirmed that no specimen exceeded the tentative regulatory limit.

  8. Non-Carbon Dyes For Platic Scintillators- Report

    SciTech Connect

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

    2015-10-19

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

  9. Design of high-efficiency, radiation-hard, GaInP/GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Kurtz, Sarah R.; Bertness, K. A.; Kibbler, A. E.; Kramer, C.; Olson, J. M.

    1994-01-01

    In recently years, Ga(0.5)In((0.5)P/GaAs cells have drawn increased attention both because of their high efficiencies and because they are well suited for space applications. They can be grown and processed as two-junction devices with roughly twice the voltage and half the current of GaAs cells. They have low temperature coefficients, and have good potential for radiation hardness. We have previously reported the effects of electron irradiation on test cells which were not optimally designed for space. From those results we estimated that an optimally designed cell could achieve 20 percent after irradiation with 10(exp 15) cm(exp -2) 1 MeV electrons. Modeling studies predicted that slightly higher efficiencies may be achievable. Record efficiencies for EOL performance of other types of cells are significantly lower. Even the best Si and InP cells have BOL efficiencies lower than the EOL efficiency we report here. Good GaAs cells have an EOL efficiency of 16 percent. The InP/Ga(0.5)In(0.5)As two-junction, two-terminal device has a BOL efficiency as high as 22.2 percent, but radiation results for these cells were limited. In this study we use the previous modeling and irradiation results to design a set of Ga(0.5)In(0.5)P/GaAs cells that will demonstrate the importance of the design parameters and result in high-efficiency devices. We report record AMO efficiencies: a BOL efficiency of 25.7 percent for a device optimized for BOL performance and two of different designs with EOL efficiencies of 19.6 percent (at 10(exp 15) cm(exp -2) 1MeV electrons). We vary the bottom-cell base doping and the top-cell thickness to show the effects of these two important design parameters. We get an unexpected result indicating that the dopant added to the bottom-cell base also increases the degradation of the top cell.

  10. Radiation hardness of Ga0.5In0.5 P/GaAs tandem solar cells

    NASA Technical Reports Server (NTRS)

    Kurtz, Sarah R.; Olson, J. M.; Bertness, K. A.; Friedman, D. J.; Kibbler, A.; Cavicchi, B. T.; Krut, D. D.

    1991-01-01

    The radiation hardness of a two-junction monolithic Ga sub 0.5 In sub 0.5 P/GaAs cell with tunnel junction interconnect was investigated. Related single junction cells were also studied to identify the origins of the radiation losses. The optimal design of the cell is discussed. The air mass efficiency of an optimized tandem cell after irradiation with 10(exp 15) cm (-2) 1 MeV electrons is estimated to be 20 percent using currently available technology.

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

    NASA Astrophysics Data System (ADS)

    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. Scintillator based beta batteries

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  13. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Effect of compression of a laser plasma on the generation of harmonics and hard x radiation

    NASA Astrophysics Data System (ADS)

    Apollonov, V. V.; Derzhavin, S. I.; Kazakov, K. Kh

    1993-02-01

    A compression of a plasma produced at a conical target by a low-intensity beam (q≲10 GW/cm2) from a CO2 laser has been studied. The effect of this compression on the onset of the parametric instability responsible for the generation of harmonics and of hard x radiation has also been studied. A qualitative interpretation of the results is offered.

  14. Large volume flow-through scintillating detector

    DOEpatents

    Gritzo, Russ E.; Fowler, Malcolm M.

    1995-01-01

    A large volume flow through radiation detector for use in large air flow situations such as incinerator stacks or building air systems comprises a plurality of flat plates made of a scintillating material arranged parallel to the air flow. Each scintillating plate has a light guide attached which transfers light generated inside the scintillating plate to an associated photomultiplier tube. The output of the photomultiplier tubes are connected to electronics which can record any radiation and provide an alarm if appropriate for the application.

  15. The radiation hardness and temperature stability of Planar Light-wave Circuit splitters for the High Luminosity LHC

    NASA Astrophysics Data System (ADS)

    Ryder, N. C.; Hamilton, P.; Huffman, B. T.; Teng, P. K.; Weidberg, A. R.; Issever, C.

    2011-10-01

    High Luminosity LHC (HL-LHC) Inner Tracker designs may include the sharing of Timing, Trigger and Control (TTC) signals between several tracker modules. This is possible because the highest frequency signals are common to all modules. Such designs are an attractive option because they reduce the number of optical links required and hence the cost. These designs will require optical signal splitters that are radiation hard up to high doses and capable of operating in cold temperatures. Optical splitters are available as either fused-fibre splitters or Planar Light-wave Circuit (PLC) splitters. PLC splitters are preferable because they are smaller than fused-fibre splitters. A selection of PLC splitters from different manufacturers and of two different technologies (silica and glass based) have been tested for radiation hardness up to a dose of 500 kGy(Si) and for temperature stability. All the tested splitters displayed small increases in insertion losses ( < 0.1 dB) in reducing the operating temperature from 25°C to -25°C. The silica based splitters from all manufacturers did not exhibit significant radiation induced insertion losses, despite the high dose they were exposed to. The glass based sample, however, had a per channel radiation induced insertion loss of up to 1.16 dB. Whilst the silica based splitters can be considered as qualified for HL-LHC use with regards to radiation hardness, the glass technology would require further testing at a lower, more realistic, dose to also be considered as a potential component for HL-LHC upgrade designs.

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

    PubMed

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

    2011-12-01

    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. 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 × 26 cm(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. The detector array that we developed allowed us to measure doses with an average precision of better than 1% for cumulated doses equal to or greater than 6.3 cGy. Our results showed that the dose distributions produced by the 6-MV photon beam are not perturbed (within ±1.1%) by the presence of the hundreds of PSDs located into the phantom. The results also showed that the variations in the beam incidences have little effect on the dose response of the device. For all incidences tested, the passing rates of the gamma tests between the 2D-PSDA and the treatment planning

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

    SciTech Connect

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

    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

  18. Radiation hazards and lifetime risk assessment of tap water using liquid scintillation counting and high-resolution gamma spectrometry.

    PubMed

    Al-Shboul, K F; Alali, A E; Batayneh, I M; Al-Khodire, H Y

    2017-09-12

    In this work, two complementary techniques, viz. liquid scintillation counting and high-resolution gamma spectrometry are utilized to analyze radionuclides concentrations in tap water of Irbid governorate, Jordan, and study their correlation. Gross alpha and gross beta concentrations, in the tap water samples collected from the nine districts of Irbid governorate, ranged from <82 to 484 mBq/L with a mean of 295 mBq/L and from <216 to 984 mBq/L with a mean of 611 mBq/L, respectively. Furthermore, gamma spectrometry analysis, for the tap water samples, shows that the activity concentrations of (226)Ra, (232)Th, and (40)K ranged between <19 and 302 mBq/L, 24 to 119 mBq/L, and <101 to 342 mBq/L, respectively. There was a weak or even no correlation among the identified natural radionuclides with no trace of artificial radioactivity. In addition, the results of both techniques show that storing tap water in drilled wells leads to higher levels of radioactivity concentrations beyond the international permissible limits. Furthermore, the average lifetime risk and annual effective dose received by age-grouped inhabitants due to direct and indirect tap water consumption are evaluated, where most of the received dose is attributed to (226)Ra. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    PubMed Central

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

    2013-01-01

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

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

    DOEpatents

    Kauffman, Joel M.

    1994-01-01

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

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

    DOEpatents

    Kauffman, J.M.

    1994-03-29

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

  2. A built-in SRAM for radiation hard CMOS pixel sensors dedicated to high energy physics experiments

    NASA Astrophysics Data System (ADS)

    Wei, Xiaomin; Gao, Deyuan; Doziere, Guy; Hu, Yann

    2013-02-01

    CMOS pixel sensors (CPS) are attractive candidates for charged particle tracking in high energy physics experiments. However, CPS chips fabricated with standard CMOS processes, especially the built-in SRAM IP cores, are not radiation hard enough for this application. This paper presents a radiation hard SRAM for improving the CPS radiation tolerance. The SRAM cell is hardened by increasing the static noise margin (SNM) and adding P+ guard rings in layout. The peripheral circuitry is designed by building a radiation-hardened logic library. The SRAM internal timing control is hardened by a self-adaptive timing design. Finally, the SRAM design was implemented and tested in the Austriamicrosystems (AMS) 0.35 μm standard CMOS process. The prototype chips are adapted to work with frequencies up to 80 MHz, power supply voltages from 2.9 V to 3.3 V and temperatures from 0 °C to 60 °C. The single event latchup (SEL) tolerance is improved from 5.2 MeV cm2/mg to above 56 MeV cm2/mg. The total ionizing dose (TID) tolerance is enhanced by the P+ guard rings and the self-adaptive timing design. The single event upset (SEU) effects are also alleviated due to the high SNM SRAM cell and the P+ guard rings. In the near future, the presented SRAM will be integrated in the CPS chips for the STAR experiments.

  3. The readout electronics for Plastic Scintillator Detector of DAMPE

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  4. RADECS Short Course Section 4 Radiation Hardness Assurance (RHA) for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian

    2003-01-01

    Contents include the following: Introduction. Programmatic aspects of RHA. RHA componens: requirements and specifications; mission radiation environment; and parts selection and radiation tolerance. Analysis at the function/subsystem/system level: TID/DD; SEE. Conclusion.

  5. Polycrystalline scintillators for large area detectors in HEP experiments

    NASA Astrophysics Data System (ADS)

    Dosovitskiy, G.; Fedorov, A.; Karpyuk, P.; Kuznetsova, D.; Mikhlin, A.; Kozlov, D.; Dosovitskiy, A.; Korjik, M.

    2017-06-01

    After significant increase of the accelerator luminosity throughout the High Luminosity phase of LHC, charged hadrons and neutrons with fluences higher than 1014 p/cm2 per year in the largest pseudo-rapidity regions of the detectors will cause increased radiation damage of materials. Increasing activation of the experimental equipment will make periodical maintenance and replacement of detector components difficult. Therefore, the selected materials for new detectors should be tolerant to radiation damage. Y3Al5O12:Ce (YAG:Ce) crystal was found to be one of the most radiation hard scintillation materials. However, production of YAG:Ce in a single crystalline form is costly, because crystal growth is performed at temperature near 1900°C with a very low rate of transformation of a raw material into a crystal. We propose translucent YAG:Ce ceramics as an alternative cheaper solution. Ceramic samples were sintered up to density ~98% of the theoretical value and were translucent. The samples have demonstrated light yield of 2200 phot./MeV under 662 keV γ-quanta, which gives the expected response to minimum ionizing particle around 3000 phot. for 2 mm thick plate. Scintillation light yield, registered under surface layer excitation with α-particles, was 50-70% higher than for the reference single crystal YAG:Ce.

  6. High-resolution single-shot spectral monitoring of hard x-ray free-electron laser radiation

    SciTech Connect

    Makita, M.; Karvinen, P.; Zhu, D.; Juranic, P. N.; Grünert, J.; Cartier, S.; Jungmann-Smith, J. H.; Lemke, H. T.; Mozzanica, A.; Nelson, S.; Patthey, L.; Sikorski, M.; Song, S.; Feng, Y.; David, C.

    2015-10-16

    We have developed an on-line spectrometer for hard x-ray free-electron laser (XFEL) radiation based on a nanostructured diamond diffraction grating and a bent crystal analyzer. Our method provides high spectral resolution, interferes negligibly with the XFEL beam, and can withstand the intense hard x-ray pulses at high repetition rates of >100 Hz. The spectrometer is capable of providing shot-to-shot spectral information for the normalization of data obtained in scientific experiments and optimization of the accelerator operation parameters. We have demonstrated these capabilities of the setup at the Linac Coherent Light Source, in self-amplified spontaneous emission mode at full energy of >1 mJ with a 120 Hz repetition rate, obtaining a resolving power of Ε/δΕ > 3 × 104. In conclusion, the device was also used to monitor the effects of pulse duration down to 8 fs by analysis of the spectral spike width.

  7. Effects of quenching, irradiation, and annealing processes on the radiation hardness of silica fiber cladding materials (I)

    NASA Astrophysics Data System (ADS)

    Wen, Jianxiang; Gong, Renxiang; Xiao, Zhongyin; Luo, Wenyun; Wu, Wenkai; Luo, Yanhua; Peng, Gang-ding; Pang, Fufei; Chen, Zhenyi; Wang, Tingyun

    2016-07-01

    Silica optical fiber cladding materials were experimentally treated by a series of processes. The treatments involved quenching, irradiation, followed by annealing and subsequent re-irradiation, and they were conducted in order to improve the radiation hardness. The microstructural properties of the treated materials were subsequently investigated. Following the treatment of the optical fiber cladding materials, the results from the electron spin resonance (ESR) analysis demonstrated that there was a significant decrease in the radiation-induced defect structures. The ESR signals became significantly weaker when the samples were annealed at 1000 °C in combination with re-irradiation. In addition, the microstructure changes within the silica optical fiber cladding material were also analyzed using Raman spectroscopy. The experimental results demonstrate that the Sisbnd Osbnd Si bending vibrations at ω3 = 800-820 cm-1 and ω4 = 1000-1200 cm-1 (with longitudinal optical (LO) and transverse optical (TO) splitting bands) were relatively unaffected by the quenching, irradiation, and annealing treatments. In particular, the annealing process resulted in the disappearance of the defect centers; however, the LO and TO modes at the ω3 and ω4 bands were relatively unchanged. With the additional support of the ESR test results, we can conclude that the combined treatment processes can significantly enhance the radiation hardness properties of the optical fiber cladding materials.

  8. SU-E-T-774: Use of a Scintillator-Mirror-Camera System for the Measurement of MLC Leakage Radiation with the CyberKnife M6 System

    SciTech Connect

    Goggin, L; Kilby, W; Noll, M; Maurer, C

    2015-06-15

    Purpose: A technique using a scintillator-mirror-camera system to measure MLC leakage was developed to provide an efficient alternative to film dosimetry while maintaining high spatial resolution. This work describes the technique together with measurement uncertainties. Methods: Leakage measurements were made for the InCise™ MLC using the Logos XRV-2020A device. For each measurement approximately 170 leakage and background images were acquired using optimized camera settings. Average background was subtracted from each leakage frame before filtering the integrated leakage image to replace anomalous pixels. Pixel value to dose conversion was performed using a calibration image. Mean leakage was calculated within an ROI corresponding to the primary beam, and maximum leakage was determined by binning the image into overlapping 1mm x 1mm ROIs. 48 measurements were performed using 3 cameras and multiple MLC-linac combinations in varying beam orientations, with each compared to film dosimetry. Optical and environmental influences were also investigated. Results: Measurement time with the XRV-2020A was 8 minutes vs. 50 minutes using radiochromic film, and results were available immediately. Camera radiation exposure degraded measurement accuracy. With a relatively undamaged camera, mean leakage agreed with film measurement to ≤0.02% in 92% cases, ≤0.03% in 100% (for maximum leakage the values were 88% and 96%) relative to reference open field dose. The estimated camera lifetime over which this agreement is maintained is at least 150 measurements, and can be monitored using reference field exposures. A dependency on camera temperature was identified and a reduction in sensitivity with distance from image center due to optical distortion was characterized. Conclusion: With periodic monitoring of the degree of camera radiation damage, the XRV-2020A system can be used to measure MLC leakage. This represents a significant time saving when compared to the traditional

  9. Radiation hardness of a polycrystalline chemical-vapor-deposited diamond detector irradiated with 14 MeV neutrons

    SciTech Connect

    Angelone, M.; Pillon, M.; Balducci, A.; Marinelli, M.; Milani, E.; Morgada, M.E.; Pucella, G.; Tucciarone, A.; Verona-Rinati, G.; Ochiai, Kentaro; Nishitani, Takeo

    2006-02-15

    Chemical-vapor-deposited (CVD) diamond films are considered as neutron detectors for nuclear fusion devices because of their radiation hardness. Data about the radiation hardness of polycrystalline CVD diamond films exposed to 14 MeV neutron are missing in literature so the actual capability of CVD diamond detectors to withstand fusion device conditions must be truly demonstrated. In this work a polycrystalline CVD diamond detector, 101 {mu}m thick, was irradiated for the first time with 14 MeV neutrons produced by the Fusion Neutron Source of the Japan Atomic Energy Research Institute with the goal to study its radiation hardness. The 14 MeV neutron fluence was 8x10{sup 14} n/cm{sup 2}. The film performances were studied before and after the 14 MeV neutron irradiation by using 5.5 MeV {alpha} from {sup 241}Am source, both in the pumped and the 'as-grown' state. A comparison with previous measurements performed in more soft neutron spectra (mean neutron energy of 1-2 MeV) is reported pointing out the more damaging effects of the 14 MeV neutrons. It was found that annealing at 500 deg. C and redeposition of the gold contact followed by a proper pumping procedure will restore more than 70% the initial working conditions of the irradiated detector. An analysis of the neutron field expected in the neutron camera of the International Thermonuclear Reactor fusion tokamak was also performed, showing the capability of CVD diamond detector to withstand the 14 MeV neutron fluence expected in about one year of operation.

  10. Apparatuses for large area radiation detection and related method

    DOEpatents

    Akers, Douglas W; Drigert, Mark W

    2015-04-28

    Apparatuses and a related method relating to radiation detection are disclosed. In one embodiment, an apparatus includes a first scintillator and a second scintillator adjacent to the first scintillator, with each of the first scintillator and second scintillator being structured to generate a light pulse responsive to interacting with incident radiation. The first scintillator is further structured to experience full energy deposition of a first low-energy radiation, and permit a second higher-energy radiation to pass therethrough and interact with the second scintillator. The apparatus further includes a plurality of light-to-electrical converters operably coupled to the second scintillator and configured to convert light pulses generated by the first scintillator and the second scintillator into electrical signals. The first scintillator and the second scintillator exhibit at least one mutually different characteristic for an electronic system to determine whether a given light pulse is generated by the first scintillator or the second scintillator.

  11. Quantitative analysis of flare accelerated electrons through their hard X-ray and microwave radiation

    NASA Technical Reports Server (NTRS)

    Klein, K. L.; Trottet, G.

    1985-01-01

    Hard X-ray and microwave modelling that takes into account the temporal evolution of the electron spectrum as well as the inhomogeneity of the magnetic field and the ambient medium in the radio source is presented. This method is illustrated for the June 29 1980 10:41 UT event. The implication on the process of acceleration/injection is discussed.

  12. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science

    SciTech Connect

    Jungmann-Smith, J. H. Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Greiffenberg, D.; Jaggi, A.; Maliakal, D.; Mayilyan, D.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruder, Ch.; Schädler, L.; Schmitt, B.; Shi, X.; Tinti, G.; Cartier, S.; Medjoubi, K.

    2015-12-15

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10{sup 4} photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm{sup 2} pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm{sup 2}. Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  13. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science

    NASA Astrophysics Data System (ADS)

    Jungmann-Smith, J. H.; Bergamaschi, A.; Brückner, M.; Cartier, S.; Dinapoli, R.; Greiffenberg, D.; Jaggi, A.; Maliakal, D.; Mayilyan, D.; Medjoubi, K.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruder, Ch.; Schädler, L.; Schmitt, B.; Shi, X.; Tinti, G.

    2015-12-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 104 photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm2 pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm2. Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  14. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science.

    PubMed

    Jungmann-Smith, J H; Bergamaschi, A; Brückner, M; Cartier, S; Dinapoli, R; Greiffenberg, D; Jaggi, A; Maliakal, D; Mayilyan, D; Medjoubi, K; Mezza, D; Mozzanica, A; Ramilli, M; Ruder, Ch; Schädler, L; Schmitt, B; Shi, X; Tinti, G

    2015-12-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10(4) photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm(2) pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm(2). Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  15. Liquid scintillators for optical fiber applications

    SciTech Connect

    Franks, L.A.; Lutz, S.S.

    1982-11-16

    A multicomponent liquid scintillator solution for use as a radiation-to-light converter in conjunction with a fiber optic transmission system. The scintillator includes a quantity of 1, 2 , 4, 5, 3H, 6H, 1 OH, tetrahydro-8-trifluoromethyl (1) benzopyrano (9, 9a, 1-gh) quinolizin-10-one (Coumarin) as a solute in a fluor solvent such as benzyl alcohol or pseudocumene. The use of bibuq as an additional or primary solute is also disclosed.

  16. Current status on plastic scintillators modifications.

    PubMed

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

    2014-11-24

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

  17. Liquid scintillators for optical fiber applications

    DOEpatents

    Franks, Larry A.; Lutz, Stephen S.

    1982-01-01

    A multicomponent liquid scintillator solution for use as a radiation-to-light converter in conjunction with a fiber optic transmission system. The scintillator includes a quantity of 1, 2, 4, 5, 3H, 6H, 1 OH, tetrahydro-8-trifluoromethyl (1) benzopyrano (9, 9a, 1-gh) quinolizin-10-one (Coumarin) as a solute in a fluor solvent such as benzyl alcohol or pseudo-cumene. The use of BIBUQ as an additional or primary solute is also disclosed.

  18. Ternary liquid scintillator for optical fiber applications

    DOEpatents

    Franks, Larry A.; Lutz, Stephen S.

    1982-01-01

    A multicomponent liquid scintillator solution for use as a radiation-to-light converter in conjunction with a fiber optic transmission system. The scintillator includes a quantity of 5-amino-9-diethylaminobenz (a) phenoxazonium nitrate (Nile Blue Nitrate) as a solute in a fluor solvent such as benzyl alcohol. The use of PPD as an additional solute is also disclosed. The system is controllable by addition of a suitable quenching agent, such as phenol.

  19. 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

    SciTech Connect

    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.

    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)

  20. Radiation hardness of gas discharge tubes and avalanche diodes used for transient voltage suppression

    NASA Astrophysics Data System (ADS)

    Osmokrović, P.; Jurosević, M.; Stanković, K.; Vujisić, M.

    The widespread use of gas discharge tubes (GDTs) and avalanche diodes for transient voltage suppression (TVS) in many cases results in their exposure to ionizing radiation. The aim of this paper is to investigate the influence of irradiation on these TVS devices' characteristics, by exposing them to a combined neutron/gamma radiation field. Experimental results show that irradiation of TVS diodes causes a lasting degradation of their protective characteristics. On the other hand, GDTs exhibit a temporary change of performance. The observed effects are presented with the accompanying theoretical interpretations, based on the interaction of radiation with materials constituting the investigated devices.

  1. RADIATION HARDNESS / TOLERANCE OF SI SENSORS / DETECTORS FOR NUCLEAR AND HIGH ENERGY PHYSICS EXPERIMENTS.

    SciTech Connect

    LI,Z.

    2002-09-09

    Silicon sensors, widely used in high energy and nuclear physics experiments, suffer severe radiation damage that leads to degradations in sensor performance. These degradations include significant increases in leakage current, bulk resistivity, and space charge concentration. The increase in space charge concentration is particularly damaging since it can significantly increase the sensor full depletion voltage, causing either breakdown if operated at high biases or charge collection loss if operated at lower biases than full depletion. Several strategies can be used to make Si detectors more radiation had tolerant to particle radiations. In this paper, the main radiation induced degradations in Si detectors will be reviewed. The details and specifics of the new engineering strategies: material/impurity/defect engineering (MIDE); device structure engineering (DSE); and device operational mode engineering (DOME) will be given.

  2. Radiation Hardness Assurance Issues Associated with COTS in JPL Flight Systems: The Challenge of Europa

    NASA Technical Reports Server (NTRS)

    Barnes, C.; Johnston, A.

    1999-01-01

    With the decreasing availability of radiation hardened electronics and the new NASA paradigm of faster, more aggressive and less expensive space missions, there has been an increasing emphasis on using high performance commercial microelectronic parts and circuits in NASA spacecraft.

  3. The Ganymede Laser Altimeter - Instrument Design Overview with Radiation hard Transmitter

    NASA Astrophysics Data System (ADS)

    Althaus, C.; Hussmann, H.; Lingenauber, K.; Michaelis, H.; Kallenbach, R.; Oberst, J.

    2016-10-01

    The Ganymede Laser Altimeter (GALA) onboard of JUICE mission shall investigate Ganymede. A laser provides the measuring signal and has therefore to be robust and reliable in the environment of Jupiter, in particular with regard to radiation.

  4. A Radiation-Hard Silicon Drift Detector Array for Extraterrestrial Element Mapping

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Chen, Wei; De Geronimo, Gianluigi; Keister, Jeff; Li, Shaouri; Li, Zhen; Siddons, David P.; Smith, Graham

    2011-01-01

    Measurement of x-rays from the surface of objects can tell us about the chemical composition Absorption of radiation causes characteristic fluorescence from material being irradiated. By measuring the spectrum of the radiation and identifying lines in the spectrum, the emitting element (s) can be identified. This technique works for any object that has no absorbing atmosphere and significant surface irradiation : Our Moon, the icy moons of Jupiter, the moons of Mars, the planet Mercury, Asteroids and Comets

  5. Radiation-hard analog-to-digital converters for space and strategic applications

    NASA Technical Reports Server (NTRS)

    Gauthier, M. K.; Dantas, A. R. V.

    1985-01-01

    During the course of the Jet Propulsion Laboratory's program to study radiation-hardened analog-to-digital converters (ADCs), numerous milestones have been reached in manufacturers' awareness and technology development and transfer, as well as in user awareness of these developments. The testing of ADCs has also continued with twenty different ADCs from seven manufacturers, all tested for total radiation dose and three tested for neutron effects. Results from these tests are reported.

  6. High resolution scintillation detector with semiconductor readout

    DOEpatents

    Levin, Craig S.; Hoffman, Edward J.

    2000-01-01

    A novel high resolution scintillation detector array for use in radiation imaging such as high resolution Positron Emission Tomography (PET) which comprises one or more parallelepiped crystals with at least one long surface of each crystal being in intimate contact with a semiconductor photodetector such that photons generated within each crystal by gamma radiation passing therethrough is detected by the photodetector paired therewith.

  7. High latitude scintillations

    NASA Astrophysics Data System (ADS)

    Basu, Santimay; Basu, Sunanda

    High-latitude phase and amplitude scintillations have been observed with quasi-geostationary polar beacon satellites, high-altitude orbiting GPS satellites, and low-altitude orbiting HiLat and Polar Bear satellites. The scintillation behavior observed in the polar cap, cusp, and nightside auroral oval is described. Consideration is given to the possible mechanisms for the generation of irregularities that cause scintillations. The importance of coordinated multitechnique measurements for scintillation studies is stressed.

  8. Scintillation of lead tungstate crystal studied with single-electron beam from KUFEL

    SciTech Connect

    Rizwan, Mohamad Uozumi, Yusuke; Matsuo, Kazuki; Ohgaki, Hideaki; Kii, Toshiteru; Zen, Heishun; Tsamalaidze, Zviadi; Evtoukhovitch, Petr; Valentin, Samoilov

    2015-04-29

    Lead tungstate (PWO) crystal has a very fast response, high atomic density and high radiation hardness. Therefore, they are suitable to be used for high-energy nuclear data measurements under high-background circumstances. Although a good electron-ion separation with a pulse shape analysis technique is essential, scintillation pulse shapes have not been observed with electron beams of a wide energy range. A single-electron beam technique has been developed at Kyoto University Free Electron Laser (KUFEL), and electron beams of 4-38 MeV are available. During the experiments, single electron beams bombarded a PWO crystal. By using oscilloscope we observed scintillation pulses of a PWO crystal coupled with a photomultiplier tube. Measured spectra were compared with the simulation code of EGS5 to analyze scattering effects. As the result, the pulse amplitudes show good linearity and the pulse shapes are almost constant in the observed energy range.

  9. World Health Organization, radiofrequency radiation and health - a hard nut to crack (Review).

    PubMed

    Hardell, Lennart

    2017-08-01

    In May 2011 the International Agency for Research on Cancer (IARC) evaluated cancer risks from radiofrequency (RF) radiation. Human epidemiological studies gave evidence of increased risk for glioma and acoustic neuroma. RF radiation was classified as Group 2B, a possible human carcinogen. Further epidemiological, animal and mechanistic studies have strengthened the association. In spite of this, in most countries little or nothing has been done to reduce exposure and educate people on health hazards from RF radiation. On the contrary ambient levels have increased. In 2014 the WHO launched a draft of a Monograph on RF fields and health for public comments. It turned out that five of the six members of the Core Group in charge of the draft are affiliated with International Commission on Non-Ionizing Radiation Protection (ICNIRP), an industry loyal NGO, and thus have a serious conflict of interest. Just as by ICNIRP, evaluation of non-thermal biological effects from RF radiation are dismissed as scientific evidence of adverse health effects in the Monograph. This has provoked many comments sent to the WHO. However, at a meeting on March 3, 2017 at the WHO Geneva office it was stated that the WHO has no intention to change the Core Group.

  10. World Health Organization, radiofrequency radiation and health - a hard nut to crack (Review)

    PubMed Central

    Hardell, Lennart

    2017-01-01

    In May 2011 the International Agency for Research on Cancer (IARC) evaluated cancer risks from radiofrequency (RF) radiation. Human epidemiological studies gave evidence of increased risk for glioma and acoustic neuroma. RF radiation was classified as Group 2B, a possible human carcinogen. Further epidemiological, animal and mechanistic studies have strengthened the association. In spite of this, in most countries little or nothing has been done to reduce exposure and educate people on health hazards from RF radiation. On the contrary ambient levels have increased. In 2014 the WHO launched a draft of a Monograph on RF fields and health for public comments. It turned out that five of the six members of the Core Group in charge of the draft are affiliated with International Commission on Non-Ionizing Radiation Protection (ICNIRP), an industry loyal NGO, and thus have a serious conflict of interest. Just as by ICNIRP, evaluation of non-thermal biological effects from RF radiation are dismissed as scientific evidence of adverse health effects in the Monograph. This has provoked many comments sent to the WHO. However, at a meeting on March 3, 2017 at the WHO Geneva office it was stated that the WHO has no intention to change the Core Group. PMID:28656257

  11. Scintillator manufacture at Fermilab

    SciTech Connect

    Mellott, K.; Bross, A.; Pla-Dalmau, A.

    1998-08-01

    A decade of research into plastic scintillation materials at Fermilab is reviewed. Early work with plastic optical fiber fabrication is revisited and recent experiments with large-scale commercial methods for production of bulk scintillator are discussed. Costs for various forms of scintillator are examined and new development goals including cost reduction methods and quality improvement techniques are suggested.

  12. Scintillator materials for calorimetry

    SciTech Connect

    Weber, M.J.

    1994-09-01

    Requirements for fast, dense scintillator materials for calorimetry in high energy physics and approaches to satisfying these requirements are reviewed with respect to possible hosts and luminescent species. Special attention is given to cerium-activated crystals, core-valence luminescence, and glass scintillators. The present state of the art, limitations, and suggestions for possible new scintillator materials are presented.

  13. Scintillator manufacture at Fermilab

    NASA Astrophysics Data System (ADS)

    Mellott, K.; Bross, A.; Pla-Dalmau, A.

    1998-11-01

    A decade of research into plastic scintillation materials at Fermilab is reviewed. Early work with plastic optical fiber fabrication is revisited and recent experiments with large-scale commercial methods for production of bulk scintillator are discussed. Costs for various forms of scintillator are examined and new development goals including cost reduction methods and quality improvement techniques are suggested.

  14. Low-mass, intrinsically-hard high temperature radiator. Final report, Phase I

    SciTech Connect

    1990-07-15

    This paper reports on the investigation of layered ceramic/metal composites in the design of low-mass hardened radiators for space heat rejection systems. The investigation is part of the Strategic Defence Initiative. This effort evaluated the use of layered composites as a material to form thin-walled, vacuum leaktight heat pipes. The heat pipes would be incorporated into a large heat pipe radiator for waste heat rejection from a space nuclear power source. Composite materials evaluations were performed on combinations of refractory metals and ceramic powders. Fabrication experiments were performed to demonstrate weldability. Two titanium/titanium diboride composite tubes were successfully fabricated into potassium heat pipes and operated at temperatures in excess of 700C. Testing and analysis for composite tubes are described in the report. The study has verified the feasibility of using layered composites for forming thin-walled, light weight heat pipe tubes for use in hardened space radiators.

  15. Improvement of the radiation hardness of a directly converting high resolution intra-oral X-ray imaging sensor

    NASA Astrophysics Data System (ADS)

    Spartiotis, Konstantinos; Pyyhtiä, Jouni; Schulman, Tom

    2003-11-01

    The radiation tolerance of a directly converting digital intra-oral X-ray imaging sensor reported in Spartiotis et al. [Nucl. Instr. and Meth. A 501 (2003) 594] has been tested using a typical dental X-ray beam spectrum. Radiation induced degradation in the performance of the sensor which consists of CMOS signal readout circuits bump bonded to a high resistivity silicon pixel detector was observed already before a dose (in air) of 1 krad. Both increase in the leakage current of the pixel detector manufactured by Sintef, Norway and signal leakage to ground from the gate of the pixel input MOSFETs of the readout circuit were observed and measured. The sensitive part of the CMOS circuit was identified as the protection diode of the gate of the input MOSFET. After removing the gate protection diode no signal leakage was observed up to a dose of 5 krad (air) which approximately corresponds to 125.000 typical dental X-ray exposures. The radiation hardness of the silicon pixel detector was improved by using a modified oxidation process supplied by Colibrys, Switzerland. The improved pixel detectors showed no increase in the leakage current at dental doses.

  16. Determination of the scintillator decay time by the autocorrelation method

    NASA Astrophysics Data System (ADS)

    Morozov, V. A.; Morozova, N. V.

    2017-09-01

    An autocorrelation method is developed for determining the composition and decay time of scintillators. This method also allows studying the spatial distribution of nuclear radiation and controlling the amount of the dopants introduced in the scintillator. The decay time is measured from a few nanoseconds to microseconds. It is found out that the decay time increases in plastic scintillators with a wavelength shifter and a Gd doped.

  17. Scintillator reflective layer coextrusion

    DOEpatents

    Yun, Jae-Chul; Para, Adam

    2001-01-01

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

  18. Study of dose-rate effects on the radiation damage of polymer-based SCSN23, SCSN81, SCSN81+Y7, SCSN81+Y8 and 3HF scintillators

    NASA Astrophysics Data System (ADS)

    Giokaris, N. D.; Contreras, M.; Pla-Dalmau, A.; Zimmerman, J.; Johnson, K. F.

    1993-01-01

    Samples of commercial, polymer-based scintillators (SCSN23, SCSN81, SCSN81+Y7, SCSN81+Y8 and 3HF) have been exposed in air to a radiation dose of 1.3 Mrad and at a dose rate of 267 rad/h from a 60Co source. The light yield and attenuation length were measured before and after irradiation. Results on the relative change in the light yield and the attenuation length versus dose are reported and they are compared with previous measurements at higher dose rates.

  19. Nano and Micro Structures Image Based on Lens-Crystal System For Hard X-Ray Radiation

    NASA Astrophysics Data System (ADS)

    Kuyumchyan, David; Kuyumchyan, Armen; Kohn, Victor; Snigirev, Anatoly; Snigireva, Irina; Shulakov, Evgeny

    2012-02-01

    We present results of imaging properties of the lens-crystal system for hard x-ray radiation. The system is based on a beryllium parabolic refractive lens placed in front of the sample, and an asymmetric silicon single crystal placed behind the sample. We record the magnified x-ray phase contrast image at the x-ray energy 15 keV. The peculiarities of image transformation are investigated both experimentally and theoretically when the focus of refractive lens is moved across and along the optical axis. The computer program was elaborated for a simulation of image formation in the system based on the refractive lens and the crystal with asymmetric Bragg diffraction. The algorithm is based on the FFT procedure.

  20. Devices based on InGaN/GaN multiple quantum well for scintillator and detector applications

    NASA Astrophysics Data System (ADS)

    Hospodková, Alice; Pangrác, Jiří; Kuldová, Karla; Nikl, Martin; Pacherová, Oliva; Oswald, Jiří; Hubáček, Tomáš; Zíková, Markéta; Brůža, Petr; Pánek, Dalibor; Blažek, Karel; Ledoux, Gilles; Dujardin, Christophe; Heuken, Michael; Hulicius, Eduard

    2016-02-01

    Fast scintillators are necessary for electron microscopes, as well as in many other application fields like medical diagnostics and therapy and fundamental science. InGaN/GaN multiple quantum well structures (QW) are perspective candidates due to strong exciton binding energy, high quantum efficiency, short decay time in order of ns and good radiation resistance. The aim of our work is to prepare scintillator structure with fast luminescence response and high intensity of light. InGaN/GaN multiple QW structures described here were prepared by metal-organic vapour phase epitaxy and characterized by high resolution X-ray diffraction measurements. We demonstrate structure suitability for scintillator application including a unique measurement of wavelength-resolved scintillation response under nanosecond pulse soft X-ray source in extended dynamical and time scales. The photo-, radio- and cathodo-luminescence (PL, RL, CL) were measured. We observed double peak luminescence governed by different recombination mechanisms: i) exciton in QW and ii) related to defects. We have shown that for obtaining fast and intensive luminescence response proper structure design is required. The radioluminescence decay time of QW exciton maximum decreased 4 times from 16 ns to 4 ns when the QW thickness was decreased from 2.4 nm to 2 nm. We have proved suitability of InGaN/GaN structures for fast scintillator application for electron or other particle radiation detection. For x-ray detection the fast scintillation response would be hard to achieve due to the dominant slow defect luminescence maximum.

  1. Densification of sol-gel silica thin films induced by hard X-rays generated by synchrotron radiation.

    PubMed

    Innocenzi, Plinio; Malfatti, Luca; Kidchob, Tongjit; Costacurta, Stefano; Falcaro, Paolo; Marmiroli, Benedetta; Cacho-Nerin, Fernando; Amenitsch, Heinz

    2011-03-01

    In this article the effects induced by exposure of sol-gel thin films to hard X-rays have been studied. Thin films of silica and hybrid organic-inorganic silica have been prepared via dip-coating and the materials were exposed immediately after preparation to an intense source of light of several keV generated by a synchrotron source. The samples were exposed to increasing doses and the effects of the radiation have been evaluated by Fourier transform infrared spectroscopy, spectroscopic ellipsometry and atomic force microscopy. The X-ray beam induces a significant densification on the silica films without producing any degradation such as cracks, flaws or delamination at the interface. The densification is accompanied by a decrease in thickness and an increase in refractive index both in the pure silica and in the hybrid films. The effect on the hybrid material is to induce densification through reaction of silanol groups but also removal of the organic groups, which are covalently bonded to silicon via Si-C bonds. At the highest exposure dose the removal of the organic groups is complete and the film becomes pure silica. Hard X-rays can be used as an efficient and direct writing tool to pattern coating layers of different types of compositions.

  2. High-resolution single-shot spectral monitoring of hard x-ray free-electron laser radiation

    DOE PAGES

    Makita, M.; Karvinen, P.; Zhu, D.; ...

    2015-10-16

    We have developed an on-line spectrometer for hard x-ray free-electron laser (XFEL) radiation based on a nanostructured diamond diffraction grating and a bent crystal analyzer. Our method provides high spectral resolution, interferes negligibly with the XFEL beam, and can withstand the intense hard x-ray pulses at high repetition rates of >100 Hz. The spectrometer is capable of providing shot-to-shot spectral information for the normalization of data obtained in scientific experiments and optimization of the accelerator operation parameters. We have demonstrated these capabilities of the setup at the Linac Coherent Light Source, in self-amplified spontaneous emission mode at full energy ofmore » >1 mJ with a 120 Hz repetition rate, obtaining a resolving power of Ε/δΕ > 3 × 104. In conclusion, the device was also used to monitor the effects of pulse duration down to 8 fs by analysis of the spectral spike width.« less

  3. Effects of gamma radiation on hard dental tissues of albino rats using scanning electron microscope - Part 1

    NASA Astrophysics Data System (ADS)

    El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; Maghraby, Ahmed; El-Zainy, Medhat

    2011-12-01

    In the present study, 40 adult male albino rats were used to study the effect of gamma radiation on the hard dental tissues (enamel surface, dentinal tubules and the cementum surface). The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy gamma doses. The effects of irradiated hard dental tissues samples were investigated using a scanning electron microscope. For doses up to 0.5 Gy, there was no evidence of the existence of cracks on the enamel surface. With 1 Gy irradiation dose, cracks were clearly observed with localized erosive areas. At 2 Gy irradiation dose, the enamel showed morphological alterations as disturbed prismatic and interprismatic areas. An increase in dentinal tubules diameter and a contemporary inter-tubular dentine volume decrease were observed with higher irradiation dose. Concerning cementum, low doses,<0.5 Gy, showed surface irregularities and with increase in the irradiation dose to≥1 Gy, noticeable surface irregularities and erosive areas with decrease in Sharpey's fiber sites were observed. These observations could shed light on the hazardous effects of irradiation fields to the functioning of the human teeth.

  4. Radiation hardness of two CMOS prototypes for the ATLAS HL-LHC upgrade project.

    NASA Astrophysics Data System (ADS)

    Huffman, B. T.; Affolder, A.; Arndt, K.; Bates, R.; Benoit, M.; Di Bello, F.; Blue, A.; Bortoletto, D.; Buckland, M.; Buttar, C.; Caragiulo, P.; Das, D.; Dopke, J.; Dragone, A.; Ehrler, F.; Fadeyev, V.; Galloway, Z.; Grabas, H.; Gregor, I. M.; Grenier, P.; Grillo, A.; Hoeferkamp, M.; Hommels, L. B. A.; John, J.; Kanisauskas, K.; Kenney, C.; Kramberger, J.; Liang, Z.; Mandić, I.; Maneuski, D.; Martinez-Mckinney, F.; McMahon, S.; Meng, L.; Mikuž, M.; Muenstermann, D.; Nickerson, R.; Perić, I.; Phillips, P.; Plackett, R.; Rubbo, F.; Segal, J.; Seidel, S.; Seiden, A.; Shipsey, I.; Song, W.; Stanitzki, M.; Su, D.; Tamma, C.; Turchetta, R.; Vigani, L.; Volk, J.; Wang, R.; Warren, M.; Wilson, F.; Worm, S.; Xiu, Q.; Zhang, J.; Zhu, H.

    2016-02-01

    The LHC luminosity upgrade, known as the High Luminosity LHC (HL-LHC), will require the replacement of the existing silicon strip tracker and the transistion radiation tracker. Although a baseline design for this tracker exists the ATLAS collaboration and other non-ATLAS groups are exploring the feasibility of using CMOS Monolithic Active Pixel Sensors (MAPS) which would be arranged in a strip-like fashion and would take advantage of the service and support structure already being developed for the upgrade. Two test devices made with the AMS H35 process (a High voltage or HV CMOS process) have been subjected to various radiation environments and have performed well. The results of these tests are presented in this paper.

  5. Radiation Hard Silicon Particle Detectors for Phase-II LHC Trackers

    NASA Astrophysics Data System (ADS)

    Oblakowska-Mucha, A.

    2017-02-01

    The major LHC upgrade is planned after ten years of accelerator operation. It is foreseen to significantly increase the luminosity of the current machine up to 1035 cm-2s-1 and operate as the upcoming High Luminosity LHC (HL-LHC) . The major detectors upgrade, called the Phase-II Upgrade, is also planned, a main reason being the aging processes caused by severe particle radiation. Within the RD50 Collaboration, a large Research and Development program has been underway to develop silicon sensors with sufficient radiation tolerance for HL-LHC trackers. In this summary, several results obtained during the testing of the devices after irradiation to HL-LHC levels are presented. Among the studied structures, one can find advanced sensors types like 3D silicon detectors, High-Voltage CMOS technologies, or sensors with intrinsic gain (LGAD). Based on these results, the RD50 Collaboration gives recommendation for the silicon detectors to be used in the detector upgrade.

  6. Radiation hardness test of the Philips Digital Photon Counter with proton beam

    NASA Astrophysics Data System (ADS)

    Barnyakov, M. Yu.; Frach, T.; Kononov, S. A.; Kuyanov, I. A.; Prisekin, V. G.

    2016-07-01

    The Philips Digital Photon Counter (DPC) is a silicon photomultiplier combining Geiger-mode avalanche photodiodes (G-APD) and dedicated readout electronics in the same chip. The DPC is a promising photon sensor for future RICH detectors. A known issue of G-APD is its sensitivity to radiation damage. Two DPC sensors were tested using 800 MeV/c protons. An increase of dark counting rate with proton fluence up to 4 ·1011cm-2 has been measured.

  7. Low-mass, intrinsically-hard high-temperature radiator. Final report, Phase I

    SciTech Connect

    1990-06-15

    Thermacore, Inc. of Lancaster, Pennsylvania has completed a Phase I SBIR program to investigate the use of layered ceramic/metal composites in the design of low-mass hardened radiators for space heat rejection systems. The program is being monitored by the Los Alamos National Laboratory (LANL) for the Strategic Defense Initiative Organization (SDIO). This effort evaluated the use of layered composites as a material to form thin-walled, vacuum leaktight heat pipes. The heat pipes would be incorporated into a large heat pipe radiator for waste heat rejection from a space nuclear power source. This approach forms an attractive alternative to metal or silicon-carbon fiber reinforced metal heat pipes by offering a combination of low mass and improved fabricability. Titanium has been shown to have a yield strength too low at 875{degrees}K to be a useful radiator material. A silicon carbide fiber reinforced titanium material appears to have sufficient strength at 875{degrees}K. but cannot be welded due to the continuous fibers, and the preferred heat pipe working fluid (potassium) has been demonstrated to be incompatible with silicon carbide at 875{degrees}K. Moreover, titanium does not appear to be acceptable for radiators subjected to anticipated laser threats. As part of this effort, Thermacore performed composite material evaluations on combinations of refractory metals and ceramic powders. Layered composite tube samples with wall thicknesses as thin as 0.012 inches were developed. Fabrication experiments were performed that demonstrated the weldability of layered composites. Two titanium/titanium diboride composite tubes were successfully fabricated into potassium heat pipes and operated at temperatures in excess of 700{degrees}C. A hybrid composite tube was also fabricated into a potassium heat pipe. The tube was composed of alternating layers of niobium-1% zirconium foil and layers of a mixture of titanium powder and titanium diboride powder.

  8. Radiation-hard ceramic Resistive Plate Chambers for forward TOF and T0 systems

    NASA Astrophysics Data System (ADS)

    Akindinov, A.; Dreyer, J.; Fan, X.; Kämpfer, B.; Kiselev, S.; Kotte, R.; Garcia, A. Laso; Malkevich, D.; Naumann, L.; Nedosekin, A.; Plotnikov, V.; Stach, D.; Sultanov, R.; Voloshin, K.

    2017-02-01

    Resistive Plate Chambers with ceramic electrodes are the main candidates for a use in precise multi-channel timing systems operating in high-radiation conditions. We report the latest R&D results on these detectors aimed to meet the requirements of the forward T0 counter at the CBM experiment. RPC design, gas mixture, limits on the bulk resistivity of ceramic electrodes, efficiency, time resolution, counting rate capabilities and ageing test results are presented.

  9. MNOS/SOS radiation hardness performance and reliability study. Interim report Aug 79-Aug 80

    SciTech Connect

    Hampton, F.L.; Cricchi, J.R.

    1982-05-01

    In this investigation the endurance-retention characteristics of fast-write MNOS memory structure, and radiation tolerance of metal-gate dual-dielectric and polysilicon-gate all-oxide devices have been evaluated. Writing and clearing speed have been studied with respect to the NH3:SiH4 ratio (APCVD), and NH3:SiC12H2 ratio (LPCVD). The films deposited with a low NH3:SiC12 ratios could be written and cleared with shorter pulse widths; however, a degradation in retention was observed. An improvement in the endurance retention product of a drain source protected transistor structure has been realized by oxidizing the memory nitride followed by an H2 anneal immediately after deposition. The film was deposited with a LPCVD reactor at 750 deg with a NH3:SiC12H2 ratio of 9:1. Oxidation was performed in steam at 900 C, as was the subsequent H2 anneal. The effect of total dose radiation was found to be more severe for a positive bias. The all oxide polysilicon gate transistor structures were observed to be relatively soft, however results from capacitor structures shows promise in developing a radiation tolerant polysilicon-gate all-oxide gate structure.

  10. Radiation hardness and precision timing study of silicon detectors for the CMS High Granularity Calorimeter (HGC)

    NASA Astrophysics Data System (ADS)

    Currás, Esteban; Fernández, Marcos; Gallrapp, Christian; Gray, Lindsey; Mannelli, Marcello; Meridiani, Paolo; Moll, Michael; Nourbakhsh, Shervin; Scharf, Christian; Silva, Pedro; Steinbrueck, Georg; Fatis, Tommaso Tabarelli de; Vila, Iván

    2017-02-01

    The high luminosity upgraded LHC or Phase-II is expected to increase the instantaneous luminosity by a factor of 10 beyond the LHC's design value, expecting to deliver 250 fb-1 per year for a further 10 years of operation. Under these conditions the performance degradation due to integrated radiation dose will need to be addressed. The CMS collaboration is planning to upgrade the forward calorimeters. The replacement is called the High Granularity Calorimeter (HGC) and it will be realized as a sampling calorimeter with layers of silicon detectors interleaved. The sensors will be realized as pad detectors with sizes of less that ∼1.0 cm2 and an active thickness between 100 and 300 μm depending on the position, respectively, the expected radiation levels. For an integrated luminosity of 3000 fb-1, the electromagnetic calorimetry will sustain integrated doses of 1.5 MGy (150 Mrads) and neutron fluences up to 1016 neq/cm2. A radiation tolerance study after neutron irradiation of 300, 200, and 100 μm n-on-p and p-on-n silicon pads irradiated to fluences up to 1.6×1016 neq/cm2 is presented. The properties of these diodes studied before and after irradiation were leakage current, capacitance, charge collection efficiency, annealing effects and timing capability. The results of these measurements validate these sensors as candidates for the HGC system.

  11. WE-G-BRB-04: BEST IN PHYSICS (THERAPY) - A Novel Multi-Point Plastic Scintillation Detector for in Vivo Dosimetry and Quality Assurance in Radiation Therapy.

    PubMed

    Therriault-Proulx, F; Beaulieu, L; Archambault, L; Beddar, S

    2012-06-01

    To develop a novel multi-point plastic scintillation detector (mPSD) capable of accurately measuring dose at multiple positions simultaneously with the use of a single optical guide. We built a new generation of plastic scintillation detectors composed of multiple scintillating elements along a same optical transmission line. Three different scintillating fibers were optically coupled to a single collecting optical fiber. A primary challenge for this new type of detector is that the output signal is a superposition of multiple scintillation spectra and contaminating elements. Acquisition with a spectrometry setup allows for the implementation of a new hyperspectral approach that accounts for each light-emitting component separately, and allows spectral unmixing. The mPSD and an ion chamber were irradiated in a water phantom with a 6 MV photon beam. Profiles and depth-dose curves were measured and compared between detectors. This detector and the corresponding calibration approach were also applied to Ir- 192 HDR brachytherapy. Doses measured with the mPSD were in good agreement with the ion chamber measurements for external beam irradiations. Average relative differences of (2.3±1.1)%, (1.6±0.4)% and (0.32±0.19)% were observed for each scintillating element. The mPSD measurements tended to be at least as accurate as published measurements from single-point PSDs. For the Ir-192 HDR brachytherapy application, the average difference between the treatment planning system and the measurements were (4.6±1.0)% per dwell-position and (2.1±1.0)% per catheter. The accuracy of each scintillating element was shown to depend on light attenuation and on the similarity of its scintillation spectrum in comparison to the other light emitters. The feasibility and accuracy of mPSDs using a single transmission line was demonstrated. In addition to well-documented advantages of single-point PSDs, the multi-point capability of this single-fiber detector makes mPSDs a very promising

  12. Visible scintillation photodetector device incorporating chalcopyrite semiconductor crystals

    DOEpatents

    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.

  13. Radiation hardness measurements of new permanent magnet materials for high-intensity linac applications

    SciTech Connect

    Barlow, D.B.; Kraus, R.H.; Borden, M.J.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The radiation resistance of samples of high-strength samarium cobalt permanent-magnet material has been studied. Samples of commercially available material were obtained from four different manufacturers. The remanent field of the samples was measured before and after the samples were irradiated with neutrons produced at the beam stop of the Los Alamos Neutron Science Center (LANSCE) proton accelerator.

  14. Structural Origins of Scintillation: Metal Organic Frameworks as a Nanolaboratory

    DTIC Science & Technology

    2016-06-01

    use. The results of this project provide fundamental insight into the electronic and structural features of novel scintillating materials known as...flexible structure, present unique advantages for radiation detection over existing organic scintillator materials . In addition, MOFs provide a...luminescence decay in MOFs, and will, if controlled, lead to MOFs optimized for particle identification and discrimination? (3) Can nanoporous MOFs, by

  15. Some studies of avalanche photodiode readout of fast scintillators

    SciTech Connect

    Holl, I.; Lorenz, E.; Natkaniez, S.; Renker, D.; Schmelz, C. |; Schwartz, B.

    1995-08-01

    Photomultipliers (PMs) are the classical readout element for scintillation detectors in high energy particle physics, nuclear physics, medical physics, industrial radiation monitors etc. Here, large area avalanche photodiodes with high performance, narrow operation tolerances and high reliability have recently become available. The authors report on some tests of their performance in the readout of fast scintillators.

  16. Performance of Multilayer Monochromators for Hard X-Ray Imaging with Coherent Synchrotron Radiation

    SciTech Connect

    Dietsch, R.; Holz, T.; Kraemer, M.; Weissbach, D.; Rack, A.; Weitkamp, T.; Morawe, Ch.; Cloetens, P.; Ziegler, E.; Riotte, M.; Rack, T.; Siewert, F.

    2011-09-09

    We present a study in which multilayers of different periodicity (from 2.5 to 5.5 nm), composition (W/Si, Mo/Si, Pd/B{sub 4}C, Ru/B{sub 4}C), and numbers of layers have been compared. Particularly, we chose mirrors with similar intrinsic quality (roughness and reflectivity) to study their performance (flatness and coherence of the outgoing beam) as monochromators in synchrotron radiography. The results indicate that material composition is the dominating factor for the performance. This is important to consider for future developments in synchrotron-based hard x-ray imaging methods. In these techniques, multilayer monochromators are popular because of their good tradeoff between spectral bandwidth and photon flux density of the outgoing beam, but sufficient homogeneity and preservation of the coherent properties of the reflected beam are major concerns. The experimental results we collected may help scientists and engineers specify multilayer monochromators and can contribute to better exploitation of the advantages of multilayer monochromators in microtomography and other full-field imaging techniques.

  17. Properties of scintillator solutes

    SciTech Connect

    Fluornoy, J.M.

    1998-06-01

    This special report summarizes measurements of the spectroscopic and other properties of the solutes that were used in the preparation of several new liquid scintillators developed at EG and G/Energy Measurements/Santa Barbara Operations (the precursor to Bechtel Nevada/Special Technologies Laboratory) on the radiation-to-light converter program. The data on the individual compounds are presented in a form similar to that used by Prof. Isadore Berlman in his classic handbook of fluorescence spectra. The temporal properties and relative efficiencies of the new scintillators are presented in Table 1, and the efficiencies as a function of wavelength are presented graphically in Figure 1. In addition, there is a descriptive glossary of the abbreviations used herein. Figure 2 illustrates the basic structures of some of the compounds and of the four solvents reported in this summary. The emission spectra generally exhibit more structure than the absorption spectra, with the result that the peak emission wavelength for a given compound may lie several nm away from the wavelength, {lambda}{sub avg}, at the geometric center of the emission spectrum. Therefore, the author has chosen to list absorption peaks, {lambda}{sub max}, and emission {lambda}{sub avg} values in Figures 3--30, as being most illustrative of the differences between the compounds. The compounds, BHTP, BTPB, ADBT, and DPTPB were all developed on this program. P-terphenyl, PBD, and TPB are commercially available blue emitters. C-480 and the other longer-wavelength emitters are laser dyes available commercially from Exciton Corporation. 1 ref., 30 figs.

  18. Product assurance technology for procuring reliable, radiation-hard, custom LSI/VLSI electronics

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Allen, R. A.; Blaes, B. R.; Hicks, K. A.; Jennings, G. A.; Lin, Y.-S.; Pina, C. A.; Sayah, H. R.; Zamani, N.

    1989-01-01

    Advanced measurement methods using microelectronic test chips are described. These chips are intended to be used in acquiring the data needed to qualify Application Specific Integrated Circuits (ASIC's) for space use. Efforts were focused on developing the technology for obtaining custom IC's from CMOS/bulk silicon foundries. A series of test chips were developed: a parametric test strip, a fault chip, a set of reliability chips, and the CRRES (Combined Release and Radiation Effects Satellite) chip, a test circuit for monitoring space radiation effects. The technical accomplishments of the effort include: (1) development of a fault chip that contains a set of test structures used to evaluate the density of various process-induced defects; (2) development of new test structures and testing techniques for measuring gate-oxide capacitance, gate-overlap capacitance, and propagation delay; (3) development of a set of reliability chips that are used to evaluate failure mechanisms in CMOS/bulk: interconnect and contact electromigration and time-dependent dielectric breakdown; (4) development of MOSFET parameter extraction procedures for evaluating subthreshold characteristics; (5) evaluation of test chips and test strips on the second CRRES wafer run; (6) two dedicated fabrication runs for the CRRES chip flight parts; and (7) publication of two papers: one on the split-cross bridge resistor and another on asymmetrical SRAM (static random access memory) cells for single-event upset analysis.

  19. Radiation hardness and timing studies of a monolithic TowerJazz pixel design for the new ATLAS Inner Tracker

    NASA Astrophysics Data System (ADS)

    Riegel, C.; Backhaus, M.; Van Hoorne, J. W.; Kugathasan, T.; Musa, L.; Pernegger, H.; Riedler, P.; Schaefer, D.; Snoeys, W.; Wagner, W.

    2017-01-01

    A part of the upcoming HL-LHC upgrade of the ATLAS Detector is the construction of a new Inner Tracker. This upgrade opens new possibilities, but also presents challenges in terms of occupancy and radiation tolerance. For the pixel detector inside the inner tracker, hybrid modules containing passive silicon sensors and connected readout chips are presently used, but require expensive assembly techniques like fine-pitch bump bonding. Silicon devices fabricated in standard commercial CMOS technologies, which include part or all of the readout chain, are also investigated offering a reduced cost as they are cheaper per unit area than traditional silicon detectors. If they contain the full readout chain, as for a fully monolithic approach, there is no need for the expensive flip-chip assembly, resulting in a further cost reduction and material savings. In the outer pixel layers of the ATLAS Inner Tracker, the pixel sensors must withstand non-ionising energy losses of up to 1015 n/cm2 and offer a timing resolution of 25 ns or less. This paper presents test results obtained on a monolithic test chip, the TowerJazz 180nm Investigator, towards these specifications. The presented program of radiation hardness and timing studies has been launched to investigate this technology's potential for the new ATLAS Inner Tracker.

  20. Radiation hardness of n-type SiC Schottky barrier diodes irradiated with MeV He ion microbeam

    NASA Astrophysics Data System (ADS)

    Pastuović, Željko; Capan, Ivana; Cohen, David D.; Forneris, Jacopo; Iwamoto, Naoya; Ohshima, Takeshi; Siegele, Rainer; Hoshino, Norihiro; Tsuchida, Hidekazu

    2015-04-01

    We studied the radiation hardness of 4H-SiC Schottky barrier diodes (SBD) for the light ion detection and spectroscopy in harsh radiation environments. n-Type SBD prepared on nitrogen-doped (∼4 × 1014 cm-3) epitaxial grown 4H-SiC thin wafers have been irradiated by a raster scanning alpha particle microbeam (2 and 4 MeV He2+ ions separately) in order to create patterned damage structures at different depths within a sensitive volume of tested diodes. Deep Level Transient Spectroscopy (DLTS) analysis revealed the formation of two deep electron traps in the irradiated and not thermally treated 4H-SiC within the ion implantation range (E1 and E2). The E2 state resembles the well-known Z1/2 center, while the E1 state could not be assigned to any particular defect reported in the literature. Ion Beam Induced Charge (IBIC) microscopy with multiple He ion probe microbeams (1-6 MeV) having different penetration depths in tested partly damaged 4H-SiC SBD has been used to determine the degradation of the charge collection efficiency (CCE) over a wide fluence range of damaging alpha particle. A non-linear behavior of the CCE decrease and a significant degradation of the spectroscopic performance with increasing He ion fluence were observed above the value of 1011 cm-2.

  1. Plasmonic light yield enhancement of a liquid scintillator

    SciTech Connect

    Bignell, Lindsey J.; Jackson, Timothy W.; Mume, Eskender; Lee, George P.

    2013-05-27

    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.

  2. Scintillation of Un-doped ZnO Single Crystals

    SciTech Connect

    Colosimo, A. M.; Ji, Jianfeng; Stepanov, P. S.; Boatner, L. A.; Selim, F. A.

    2016-01-07

    In this paper, scintillation properties are often studied by photo-luminescence (PL) and scintillation measurements. In this work, we combine X-ray-induced luminescence (XRIL) spectroscopy [Review of Scientific Instruments 83, 103112 (2012)] with PL and standard scintillation measurements to give insight into the scintillation properties of un-doped ZnO single crystals. XRIL revealed that ZnO luminescence proportionally increases with X-ray power and exhibits excellent linearity - indicating the possibility of developing radiation detectors with good energy resolution. Finally, by coupling ZnO crystals to fast photomultiplier tubes and monitoring the anode signal, rise times as fast as 0.9 ns were measured.

  3. Plasmonic light yield enhancement of a liquid scintillator

    NASA Astrophysics Data System (ADS)

    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.

  4. Recent development in organic scintillators

    NASA Technical Reports Server (NTRS)

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

    1969-01-01

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

  5. Depletion layer recombination effects on the radiation damage hardness of gallium arsenide cells

    NASA Technical Reports Server (NTRS)

    Garlick, G. F. J.

    1985-01-01

    The significant effect of junction depletion layer recombination on the efficiency of windowed GaAs cells was demonstrated. The effect becomes more pronounced as radiation damage occurs. The depletion is considered for 1 MeV electron fluences up to 10 to the 16th power e/sq m. The cell modeling separates damage in emitter and base or buffer layers using different damage coefficients is reported. The lower coefficient for the emitter predicts less loss of performance at fluences greater than 10 to the 15th power e/sq cm. A method for obtaining information on junction recombination effects as damage proceeds is described; this enables a more complete diagnosis of damage to be made.

  6. Hard X-ray nanofocusing at low-emittance synchrotron radiation sources

    PubMed Central

    Schroer, Christian G.; Falkenberg, Gerald

    2014-01-01

    X-ray scanning microscopy relies on intensive nanobeams generated by imaging a highly brilliant synchrotron radiation source onto the sample with a nanofocusing X-ray optic. Here, using a Gaussian model for the central cone of an undulator source, the nanobeam generated by refractive X-ray lenses is modeled in terms of size, flux and coherence. The beam properties are expressed in terms of the emittances of the storage ring and the lateral sizes of the electron beam. Optimal source parameters are calculated to obtain efficient and diffraction-limited nanofocusing. With decreasing emittance, the usable fraction of the beam for diffraction-limited nanofocusing experiments can be increased by more than two orders of magnitude compared with modern storage ring sources. For a diffraction-limited storage ring, nearly the whole beam can be focused, making these sources highly attractive for X-ray scanning microscopy. PMID:25177988

  7. Design of Si-photonic structures to evaluate their radiation hardness dependence on design parameters

    NASA Astrophysics Data System (ADS)

    Zeiler, M.; Detraz, S.; Olantera, L.; Pezzullo, G.; Seif El Nasr-Storey, S.; Sigaud, C.; Soos, C.; Troska, J.; Vasey, F.

    2016-01-01

    Particle detectors for future experiments at the HL-LHC will require new optical data transmitters that can provide high data rates and be resistant against high levels of radiation. Furthermore, new design paths for future optical readout systems for HL-LHC could be opened if there was a possibility to integrate the optical components with their driving electronics and possibly also the silicon particle sensors themselves. All these functionalities could potentially be combined in the silicon photonics technology which currently receives a lot of attention for conventional optical link systems. Silicon photonic test chips were designed in order to assess the suitability of this technology for deployment in high-energy physics experiments. The chips contain custom-designed Mach-Zehnder modulators, pre-designed ``building-block'' modulators, photodiodes and various other passive test structures. The simulation and design flow of the custom designed Mach-Zehnder modulators and some first measurement results of the chips are presented.

  8. Radiation hardness study of Silicon Detectors for the CMS High Granularity Calorimeter (HGCAL)

    NASA Astrophysics Data System (ADS)

    Currás, E.; Mannelli, M.; Moll, M.; Nourbakhsh, S.; Steinbrueck, G.; Vila, I.

    2017-02-01

    The high luminosity LHC (HL-LHC or Phase-II) is expected to increase the instantaneous luminosity of the LHC by a factor of about five, delivering 0~25 fb ‑1 per year between 2025 and 2035. Under these conditions the performance degradation of detectors due to integrated radiation dose/fluence will need to be addressed. The CMS collaboration is planning to upgrade many detector components, including the forward calorimeters. The replacement for the existing endcap preshower, electromagnetic and hadronic calorimeters is called the High Granularity Calorimeter (HGCAL) and it will be realized as a sampling calorimeter, including 40 layers of silicon detectors totalling 600 m2. The sensors will be realized as pad detectors with cell size between 0.5 and 1.0 cm2 and an active thickness between 100 μm and 300 μm depending on their location in the endcaps. The thinner sensors will be used in the highest radiation environment. For an integrated luminosity of 3000 fb ‑1, the electromagnetic calorimeter will have to sustain a maximum integrated dose of 1.5 MGy and neutron fluences of 1.0×1016 neq/cm2. A tolerance study after neutron irradiation of 300 μm, 200 μm, 100 μm and 50 μm n-on-p and p-on-n silicon pads irradiated to fluences up to 1.6×1016 neq/cm2 is presented. The main properties of these diodes have been studied before and after irradiation: leakage current, capacitance, charge collection efficiency with laser and sensitivity to minimum ionizing particles with radioactive source (90Sr). The results show a good performance even after the most extreme irradiation.

  9. Subnanosecond Scintillation Detector

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael (Inventor); Hennessy, John (Inventor); Hitlin, David (Inventor)

    2017-01-01

    A scintillation detector, including a scintillator that emits scintillation; a semiconductor photodetector having a surface area for receiving the scintillation, wherein the surface area has a passivation layer configured to provide a peak quantum efficiency greater than 40% for a first component of the scintillation, and the semiconductor photodetector has built in gain through avalanche multiplication; a coating on the surface area, wherein the coating acts as a bandpass filter that transmits light within a range of wavelengths corresponding to the first component of the scintillation and suppresses transmission of light with wavelengths outside said range of wavelengths; and wherein the surface area, the passivation layer, and the coating are controlled to increase the temporal resolution of the semiconductor photodetector.

  10. Shifting scintillator neutron detector

    DOEpatents

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

    2014-03-04

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

  11. Research activity with different types of scintillation materials

    NASA Astrophysics Data System (ADS)

    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.

  12. Study of equatorial scintillations

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  13. A Radiation Hard Multi-Channel Digitizer ASIC for Operation in the Harsh Jovian Environment

    NASA Technical Reports Server (NTRS)

    Aslam, Shahid; Aslam, S.; Akturk, A.; Quilligan, G.

    2011-01-01

    ultimately impact the surface of Europa after the mission is completed. The current JEO mission concept includes a range of instruments on the payload, to monitor dynamic phenomena (such as Io's volcanoes and Jupiters atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. The payload includes a low mass (3.7 Kg) and low power (< 5 W) Thermal Instrument (TI) concept for measuring possible warm thermal anomalies on Europa s cold surface caused by recent (< 10,000 years) eruptive activity. Regions of anomalously high heat flow will be identified by thermal mapping using a nadir pointing, push-broom filter radiometer that provides far-IR imagery in two broad band spectral wavelength regions, 8-20 m and 20-100 m, for surface temperature measurements with better than a 2 K accuracy and a spatial resolution of 250 m/pixel obtained from a 100 Km orbit. The temperature accuracy permits a search for elevated temperatures when combined with albedo information. The spatial resolution is sufficient to resolve Europa's larger cracks and ridge axial valleys. In order to accomplish the thermal mapping, the TI uses sensitive thermopile arrays that are readout by a custom designed low-noise Multi-Channel Digitizer (MCD) ASIC that resides very close to the thermopile linear array outputs. Both the thermopile array and the MCD ASIC will need to show full functionality within the harsh Jovian radiation environment, operating at cryogenic temperatures, typically 150 K to 170 K. In the following, a radiation mitigation strategy together with a low risk Radiation-Hardened-By-Design (RHBD) methodology using commercial foundry processes is given for the design and manufacture of a MCD ASIC that will meet this challenge.

  14. Spaceflight Ka-Band High-Rate Radiation-Hard Modulator

    NASA Technical Reports Server (NTRS)

    Jaso, Jeffery M.

    2011-01-01

    A document discusses the creation of a Ka-band modulator developed specifically for the NASA/GSFC Solar Dynamics Observatory (SDO). This flight design consists of a high-bandwidth, Quadriphase Shift Keying (QPSK) vector modulator with radiation-hardened, high-rate driver circuitry that receives I and Q channel data. The radiationhard design enables SDO fs Ka-band communications downlink system to transmit 130 Mbps (300 Msps after data encoding) of science instrument data to the ground system continuously throughout the mission fs minimum life of five years. The low error vector magnitude (EVM) of the modulator lowers the implementation loss of the transmitter in which it is used, thereby increasing the overall communication system link margin. The modulator comprises a component within the SDO transmitter, and meets the following specifications over a 0 to 40 C operational temperature range: QPSK/OQPSK modulator, 300-Msps symbol rate, 26.5-GHz center frequency, error vector magnitude less than or equal to 10 percent rms, and compliance with the NTIA (National Telecommunications and Information Administration) spectral mask.

  15. Real-time volumetric scintillation dosimetry

    NASA Astrophysics Data System (ADS)

    Beddar, S.

    2015-01-01

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

  16. YAP:Ce scintillator characteristics for neutron detection

    SciTech Connect

    Viererbl, L.; Klupak, V.; Vins, M.; Soltes, J.

    2015-07-01

    YAP:Ce (YAlO{sub 3}:Ce{sup +}, Yttrium Aluminum Perovskite, Ce{sup +} doped) crystals with appropriate converters seem like prospective scintillators for neutron detection. An important aspect for neutron detection with inorganic scintillators is the ability to discriminate neutron radiation from gamma radiation by pulse height of signals. For a detailed measurement of the aspect, a YAP:Ce crystal scintillator with lithium or hydrogen converters and a photomultiplier was used. A plutonium-beryllium neutron source and horizontal neutron channel beams of the LVR-15 research reactor were used as neutron sources. The measurement confirmed the possibility to use the YAP:Ce scintillator for neutron radiation detection. The degree of discrimination between neutron and gamma radiation for different detection configurations was studied. (authors)

  17. 21 CFR 892.1100 - Scintillation (gamma) camera.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Identification. A scintillation (gamma) camera is a device intended to image the distribution of radionuclides in the body by means of a photon radiation detector. This generic type of device may include...

  18. Fluorescent compounds for plastic scintillation applications

    SciTech Connect

    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.

  19. Fluorescent compounds for plastic scintillation applications

    NASA Astrophysics Data System (ADS)

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

    1994-04-01

    Several 2-(2'-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 C-60 source have also been performed.

  20. Proposal to produce novel, transparent radiation hard low refractive index polymers. Final report, 1 October-31 December 1993

    SciTech Connect

    Schuman, P.D.; Harmon, J.

    1994-02-09

    Low and high molecular weight polymers of heptafluorobutyl methacrylate, HFBM, were prepared for commercial evaluation by Bicron, an optical fiber manufacturer. Polymers were evaluated as low refractive index fiber cladding materials. Test results of Low MW polymer solutions gave excellent results. Higher MW polymers were prepared for cladding by melt co-extrusion. Corning Glass Corp, also expressed an interest in these cladding materials. These results appear to be sufficiently unique that a search has been initiated to determine patentability of the soluble fluorocarbon acrylate, methacrylate and copolymer compositions for cladding use. This research resulted in identifying a radiation hard, low refractive index polymer, poly(heptafluorobutyl methacrylate), P(HFBM) as the best candidate for a novel cladding material. P(HFBM) has a refractive index of 1.387. When used to clad a styrene core, the theoretical light propagation efficiency is 50% greater than that of styrene fiber core clad with PMMA, a common commercial cladding material. These polymers will be the only commercial fluorocarbon acrylic cladding polymers available to U.S. manufacturers. Japanese optical fiber manufacturers produce fluorocarbon clad fibers but their polymers are not available to U.S. manufacturers. These polymers can fill an urgent need in the optical fiber market.

  1. A seven-crystal Johann-type hard x-ray spectrometer at the Stanford Synchrotron Radiation Lightsource

    NASA Astrophysics Data System (ADS)

    Sokaras, D.; Weng, T.-C.; Nordlund, D.; Alonso-Mori, R.; Velikov, P.; Wenger, D.; Garachtchenko, A.; George, M.; Borzenets, V.; Johnson, B.; Rabedeau, T.; Bergmann, U.

    2013-05-01

    We present a multicrystal Johann-type hard x-ray spectrometer (˜5-18 keV) recently developed, installed, and operated at the Stanford Synchrotron Radiation Lightsource. The instrument is set at the wiggler beamline 6-2 equipped with two liquid nitrogen cooled monochromators - Si(111) and Si(311) - as well as collimating and focusing optics. The spectrometer consists of seven spherically bent crystal analyzers placed on intersecting vertical Rowland circles of 1 m of diameter. The spectrometer is scanned vertically capturing an extended backscattering Bragg angular range (88°-74°) while maintaining all crystals on the Rowland circle trace. The instrument operates in atmospheric pressure by means of a helium bag and when all the seven crystals are used (100 mm of projected diameter each), has a solid angle of about 0.45% of 4π sr. The typical resolving power is in the order of E/Δ E ˜ 10 000. The spectrometer's high detection efficiency combined with the beamline 6-2 characteristics permits routine studies of x-ray emission, high energy resolution fluorescence detected x-ray absorption and resonant inelastic x-ray scattering of very diluted samples as well as implementation of demanding in situ environments.

  2. Radiation hardness of AlxGa1-xN photodetectors exposed to Extreme UltraViolet (EUV) light beam

    NASA Astrophysics Data System (ADS)

    Malinowski, Pawel E.; John, Joachim; Barkusky, Frank; Duboz, Jean Yves; Lorenz, Anne; Cheng, Kai; Derluyn, Joff; Germain, Marianne; De Moor, Piet; Minoglou, Kyriaki; Bayer, Armin; Mann, Klaus; Hochedez, Jean-Francois; Giordanengo, Boris; Borghs, Gustaaf; Mertens, Robert

    2009-05-01

    We report on the results of fabrication and optoelectrical characterization of Gallium Nitride (GaN) based Extreme UltraViolet (EUV) photodetectors. Our devices were Schottky photodiodes with a finger-shaped rectifying contact, allowing better penetration of light into the active region. GaN layers were epitaxially grown on Silicon (111) by Metal- Organic-Chemical Vapor Deposition (MOCVD). Spectral responsivity measurements in the Near UltraViolet (NUV) wavelength range (200-400 nm) were performed to verify the solar blindness of the photodetectors. After that the devices were exposed to the EUV focused beam of 13.5 nm wavelength using table-top EUV setup. Radiation hardness was tested up to a dose of 3.3Â.1019 photons/cm2. Stability of the quantum efficiency was compared to the one measured in the same way for a commercially available silicon based photodiode. Superior behavior of GaN devices was observed at the wavelength of 13.5 nm.

  3. Radiation effects on microstructure and hardness of a titanium aluminide alloy irradiated by helium ions at room and elevated temperatures

    NASA Astrophysics Data System (ADS)

    Wei, Tao; Zhu, Hanliang; Ionescu, Mihail; Dayal, Pranesh; Davis, Joel; Carr, David; Harrison, Robert; Edwards, Lyndon

    2015-04-01

    A 45XD TiAl alloy possessing a lamellar microstructure was irradiated using 5 MeV helium ions to a fluence of 5 × 1021 ion m-2 (5000 appm) with a dose of about 1 dpa (displacements per atom). A uniform helium ion stopping damage region about 17 μm deep from the target surface was achieved by applying an energy degrading wheel. Radiation damage defects including helium-vacancy clusters and small helium bubbles were found in the microstructure of the samples irradiated at room temperature. With increasing irradiation temperature to 300 °C and 500 °C helium bubbles were clearly observed in both the α2 and γ phases of the irradiated microstructure. By means of nanoindentation significant irradiation hardening was measured. For the samples irradiated at room temperature the hardness increased from 5.6 GPa to 8.5 GPa and the irradiation-hardening effect reduced to approximately 8.0 GPa for the samples irradiated at 300 °C and 500 °C.

  4. LDQ10: a compact ultra low-power radiation-hard 4 × 10 Gb/s driver array

    DOE PAGES

    Zeng, Z.; Zhang, T.; Wang, G.; ...

    2017-02-28

    Here, a High-speed and low-power VCSEL driver is an important component of the Versatile Link for the high-luminosity LHC (HL-LHC) experiments. A compact low-power radiation-hard 4 × 10 Gb/s VCSEL driver array (LDQ10) has been developed in 65 nm CMOS technology. Each channel in LDQ10 can provide a modulation current up to 8 mA and bias current up to 12 mA. Edge pre-emphasis is employed to compensate for the bandwidth limitations due to parasitic and the turn-on delay of VCSEL devices. LDQ10 occupies a chip area of 1900 μm × 1700 μm and consumes 130 mW power for typical currentmore » settings. The modulation amplitude degrades less than 5% after 300 Mrad total ionizing dose. LDQ10 can be directly wire-bonded to the VCSEL array and it is a suitable candidate for the Versatile Link.« less

  5. Lack of progress on waveshifting fluors for use in or with polystyrene scintillators in high-energy particle detection

    SciTech Connect

    Kauffman, Joel M.; Bajwa, Gurdip S.; Litak, Peter T.; Kelley, Charles J.; Pai, Ramdas

    1998-11-09

    A number of original proton-transfer fluors were prepared as shifters for green-emitting scintillating fibers of multi-meter lengths. Quantum efficiencies up to 0.52 are reported for the new fluors which showed emission maxima between 478 and 612 nm. None proved clearly superior to 3HF, the standard fluor for scintillating fibers whose light is measured with PM tubes. For the current goal of half-meter length waveshifting fibers with blue-green emission for use with blue-violet-emitting polystyrene tiles, a number of fluors related to TPBD and Bis-MSB were prepared bearing dialkylamino auxofluors. Some of these failed to fluoresce, and those that did were photochemically unstable. A proposal was made on some original conjugated polyenes for waveshifting fibers. In general, accurate predictions could be made on excitation and emission wavelengths, while light output, decay time, photochemical stability and radiation hardness are more difficult targets.

  6. On the scintillation efficiency of carborane-loaded liquid scintillators for thermal neutron detection

    NASA Astrophysics Data System (ADS)

    Chang, Zheng; Okoye, Nkemakonam C.; Urffer, Matthew J.; Green, Alexander D.; Childs, Kyle E.; Miller, Laurence F.

    2015-01-01

    The scintillation efficiency in response to thermal neutrons was studied by loading different concentrations of carborane (0-8.5 wt%) and naphthalene (0 and 100 g/L) in five liquid organic scintillators. The sample was characterized in Pb and Cd shields under the irradiation of the thermal neutrons from a 252Cf source. A method was developed to extract the net neutron response from the pulse-height spectra. It was found that the order of scintillation efficiencies for both γ-rays and thermal neutrons is as follows: diisopropylnaphthalene>toluene (concentrated solutes)>toluene~pseudocumene~m-xylene. The quench constants, obtained by fitting the Stern-Volmer model to the plots of light output versus carborane concentration, are in the range of 0.35-1.4 M-1 for all the scintillators. The Birks factors, estimated using the specific energy loss profiles of the incident particles, are in the range of 9.3-14 mg cm-2 MeV-1 for all the samples. The light outputs are in the range of 63-86 keV electron equivalents (keVee) in response to thermal neutrons. Loading naphthalene generally promotes the scintillation efficiency of the scintillator with a benzene derivative solvent. Among all the scintillators tested, the diisopropylnaphthalene-based scintillator shows the highest scintillation efficiency, lowest Birks factor, and smallest quench constants. These properties are primarily attributed to the double fused benzene-ring structure of the solvent, which is more efficient to populate to the excited singlet state under ionizing radiation and to transfer the excitation energy to the fluorescent solutes.

  7. Saturation of a Ce:Y3Al5O12 scintillator response to ultra-short pulses of extreme ultraviolet soft X-ray and X-ray laser radiation

    DOE PAGES

    Krzywinski, J.; Andrejczuk, A.; Bionta, R. M.; ...

    2017-02-01

    Investigations of radioluminescence saturation in monocrystalline cerium doped yttrium aluminum garnet (Ce:YAG) exposed to intense extreme ultraviolet (XUV), soft X-ray and X-ray radiation delivered from three free-electron lasers are described in this article. The measurements were performed with wavelengths of 98, 25.6, 13.5 and 0.15 nm. We have found that saturation of the photon yield occurs at an excitation level of 2.0 x 1020 eV/cm3 resulting in an emission of 1.5 x 1018 visible photons per cubic centimeter. This number is much smaller than the concentration of Ce3+ in the scintillator that was equal to 2 x 1020 cm–3. Becausemore » the internal radiance efficiency η does not depend strongly on the irradiating photon energy, i.e., η ≈0.035 ± 0.015 in the range 10 to 100 000 eV, the results presented here could be used to predict saturation effects in scintillator slabs placed in imaging systems of bright XUV, X-ray and particle beams. In conclusion, the saturation of the Ce3+ emission is explained by mutual quenching of excitons created at high densities, preceding the stage of energy transfer to the Ce3+ ions.« less

  8. Thin film scintillators

    NASA Astrophysics Data System (ADS)

    McDonald, Warren; McKinney, George; Tzolov, Marian

    2015-03-01

    Scintillating materials convert energy flux (particles or electromagnetic waves) into light with spectral characteristic matching a subsequent light detector. Commercial scintillators such as yttrium aluminum garnet (YAG) and yttrium aluminum perovskite (YAP) are commonly used. These are inefficient at lower energies due to the conductive coating present on their top surface, which is needed to avoid charging. We hypothesize that nano-structured thin film scintillators will outperform the commercial scintillators at low electron energies. We have developed alternative thin film scintillators, zinc tungstate and zinc oxide, which show promise for higher sensitivity to lower energy electrons since they are inherently conductive. Zinc tungstate films exhibit photoluminescence quantum efficiency of 74%. Cathodoluminescence spectroscopy was applied in transmission and reflection geometries. The comparison between the thin films and the YAG and YAP commercial scintillators shows much higher light output from the zinc tungstate and zinc oxide at electron energies less than 5 keV. Our films were integrated in a backscattered electron detector. This detector delivers better images than an identical detector with commercial YAG scintillator at low electron energies. Dr. Nicholas Barbi from PulseTor LLC, Dr. Anura Goonewardene, NSF Grants: #0806660, #1058829, #0923047.

  9. Beta Backscatter Measures the Hardness of Rubber

    NASA Technical Reports Server (NTRS)

    Morrissey, E. T.; Roje, F. N.

    1986-01-01

    Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

  10. Beta Backscatter Measures the Hardness of Rubber

    NASA Technical Reports Server (NTRS)

    Morrissey, E. T.; Roje, F. N.

    1986-01-01

    Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

  11. Scintillation properties of polycrystalline LaxY1-xO3 ceramic

    NASA Astrophysics Data System (ADS)

    Sahi, Sunil; Chen, Wei; Kenarangui, Rasool

    2015-03-01

    Scintillators are the material that absorbs the high-energy photons and emits visible photons. Scintillators are commonly used in radiation detector for security, medical imaging, industrial applications and high energy physics research. Two main types of scintillators are inorganic single crystals and organic (plastic or liquid) scintillators. Inorganic single crystals are expensive and difficult to grow in desire shape and size. Also, some efficient inorganic scintillator such as NaI and CsI are not environmental friendly. But on the other hand, organic scintillators have low density and hence poor energy resolution which limits their use in gamma spectroscopy. Polycrystalline ceramic can be a cost effective alternative to expensive inorganic single crystal scintillators. Here we have fabricated La0.2Y1.8O3 ceramic scintillator and studied their luminescence and scintillation properties. Ceramic scintillators were fabricated by vacuum sintering of La0.2Y1.8O3 nanoparticles at temperature below the melting point. La0.2Y1.8O3 ceramic were characterized structurally using XRD and TEM. Photoluminescence and radioluminescence studies were done using UV and X-ray as an excitation source. We have used gamma isotopes with different energy to studies the scintillation properties of La0.2Y1.8O3 scintillator. Preliminary studies of La0.2Y1.8O3 scintillator shows promising result with energy resolution comparable to that of NaI and CsI.

  12. Accompanying of parameters of color, gloss and hardness on polymeric films coated with pigmented inks cured by different radiation doses of ultraviolet light

    NASA Astrophysics Data System (ADS)

    Bardi, Marcelo Augusto Gonçalves; Machado, Luci Diva Brocardo

    2012-09-01

    In the search for alternatives to traditional paint systems solvent-based, the curing process of polymer coatings by ultraviolet light (UV) has been widely studied and discussed, especially because of their high content of solids and null emission of VOC. In UV-curing technology, organic solvents are replaced by reactive diluents, such as monomers. This paper aims to investigate variations on color, gloss and hardness of print inks cured by different UV radiation doses. The ratio pigment/clear coating was kept constant. The clear coating presented higher average values for König hardness than pigmented ones, indicating that UV-light absorption has been reduced by the presence of pigments. Besides, they have indicated a slight variation in function of cure degree for the studied radiation doses range. The gloss loss related to UV light exposition allows inferring that some degradation occurred at the surface of print ink films.

  13. Silicon PM Radiation Hardness

    SciTech Connect

    Rohlf, James

    2016-08-25

    Detailed measurements have been made of 9 mm2 SiPMs from Hamamatsu (MPPC) and Zecotek (MAPD) after room temperature annealing after exposure to fluences of 1012 to 1013 cm-2. The data was used to complete the final ADR report.

  14. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E.

    1990-03-06

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  15. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E.

    1990-01-01

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  16. Review on photonic crystal coatings for scintillators

    NASA Astrophysics Data System (ADS)

    Knapitsch, Arno; Lecoq, Paul

    2014-11-01

    The amount of light and its time distribution are key factors determining the performance of scintillators when used as radiation detectors. However most inorganic scintillators are made of heavy materials and suffer from a high index of refraction which limits light extraction efficiency. This increases the path length of the photons in the material with the consequence of higher absorption and tails in the time distribution of the extracted light. Photonic crystals are a relatively new way of conquering this light extraction problem. Basically they are a way to produce a smooth and controllable index matching between the scintillator and the output medium through the nanostructuration of a thin layer of optically transparent high index material deposited at the coupling face of the scintillator. Our review paper discusses the theory behind this approach as well as the simulation details. Furthermore the different lithography steps of the production of an actual photonic crystal sample will be explained. Measurement results of LSO scintillator pixels covered with a nanolithography machined photonic crystal surface are presented together with practical tips for the further development and improvement of this technique.

  17. Segmented scintillation antineutrino detector

    DOEpatents

    Reyna, David

    2017-05-09

    The various technologies presented herein relate to incorporating a wavelength-shifting material in a scintillator to facilitate absorption of a first electromagnetic particle (e.g., a first photon) having a first wavelength and subsequent generation and emission of a second electromagnetic particle (e.g., a second photon) having a second wavelength. The second electromagnetic particle can be emitted isotropically, with a high probability that the direction of emission of the second electromagnetic particle is disparate to the direction of travel of the first electromagnetic particle (and according angle of incidence). Isotropic emission of the second electromagnetic particle enables the second electromagnetic particle to be retained in the scintillator owing to internal reflection. Accordingly, longer length scintillators can be constructed, and accordingly, the scintillator array has a greater area (and volume) over which to detect electromagnetic particles (e.g., antineutrinos) being emitted from a nuclear reaction.

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

    DOEpatents

    Neal, John S.; Mihalczo, John T.

    2006-11-28

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

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

    NASA Astrophysics Data System (ADS)

    Beaulieu, Luc; Beddar, Sam

    2016-10-01

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

  20. Scintillating pad detectors

    SciTech Connect

    Adams, D.; Baumbaugh, B.; Borcherding, F.

    1996-12-31

    We have been investigating the performance of scintillating pad detectors, individual small tiles of scintillator that are read out with wavelength-shifting fibers and visible light photon counters, for application in high luminosity colliding beam experiments such as the D0 Upgrade. Such structures could provide {open_quotes}pixel{close_quotes} type readout over large fiducial volumes for tracking, preshower detection and triggering.

  1. Progress in studying scintillator proportionality: Phenomenological model

    SciTech Connect

    Bizarri, Gregory; Cherepy, Nerine; Choong, Woon-Seng; Hull, Giulia; Moses, William; Payne, Sephen; Singh, Jai; Valentine, John; Vasilev, Andrey; Williams, Richard

    2009-04-30

    We present a model to describe the origin of non-proportional dependence of scintillator light yield on the energy of an ionizing particle. The non-proportionality is discussed in terms of energy relaxation channels and their linear and non-linear dependences on the deposited energy. In this approach, the scintillation response is described as a function of the deposited energy deposition and the kinetic rates of each relaxation channel. This mathematical framework allows both a qualitative interpretation and a quantitative fitting representation of scintillation non-proportionality response as function of kinetic rates. This method was successfully applied to thallium doped sodium iodide measured with SLYNCI, a new facility using the Compton coincidence technique. Finally, attention is given to the physical meaning of the dominant relaxation channels, and to the potential causes responsible for the scintillation non-proportionality. We find that thallium doped sodium iodide behaves as if non-proportionality is due to competition between radiative recombinations and non-radiative Auger processes.

  2. Hard tooth tissue removal by short and long Er:YAG or Er,Cr:YSGG mid-infrared laser radiation

    NASA Astrophysics Data System (ADS)

    Jelínková, H.; Dostálová, T.; Remeš, M.; Šulc, J.; Němec, M.; Fibrich, M.

    2017-02-01

    Hard dental tissue removal by laser radiation is an alternative treatment to conventional dental-drilling procedures. The advantages of this therapy are fast and localized treatment of hard dental tissue and painlessness. The most effective systems for those purposes are Er-lasers generating radiation at wavelengths of around 3 μm. The aim of this study was qualitative and quantitative examination of human dentin and ivory tissue removal by pulsed free-running (FR) and Q-switched (QSW) Er:YAG and Er,Cr:YSGG laser radiations. From the obtained results it follows that generally Er:YAG laser has lower threshold for the tissue removal in both FR and QSW regimes. Furthermore, the FR Er:YAG and Er,Cr:YSGG radiation can be effective for both dentin and ivory ablation and can prepare smooth cavities without side effects. The QSW regime is useful preferably for precise ablation of a starting tooth defect and for the part of the tooth very close to the gum. This regime is excellent for micro-preparation or for tooth treatment of children.

  3. Ionospheric Scintillation Explorer (ISX)

    NASA Astrophysics Data System (ADS)

    Iuliano, J.; Bahcivan, H.

    2015-12-01

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

  4. Semiconductor quantum dot scintillation under gamma-ray irradiation.

    PubMed

    Létant, S E; Wang, T-F

    2006-12-01

    We recently demonstrated the ability of semiconductor quantum dots to convert alpha radiation into visible photons. In this letter, we report on the scintillation of quantum dots under gamma irradiation and compare the energy resolution of the 59 keV line of americium-241 obtained with our quantum dot-glass nanocomposite to that of a standard sodium iodide scintillator. A factor 2 improvement is demonstrated experimentally and interpreted theoretically using a combination of energy-loss and photon-transport models.

  5. Ternary liquid scintillator for optical-fiber applications

    SciTech Connect

    Franks, L.A.; Lutz, S.S.

    1981-06-01

    A multicomponent liquid scintillator solution for use as a radiation-to-light converter in conjunction with a fiber optic transmission system. The scintillator includes a quantity of 5-amino-9-diethylaminobenz (a) phenoxazonium nitrate (Nile Blue Nitrate) as a solute in a fluor solvent such as benzyl alcohol. The use of PPD as an additional solute is also disclosed. The system is controllable by addition of a suitable quenching agent, such as phenol.

  6. Scintillator Measurements for SNO+

    NASA Astrophysics Data System (ADS)

    Kaptanoglu, Tanner; SNO+ Collaboration

    2016-03-01

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

  7. The Hard X-ray Imager (HXI) for the ASTRO-H Mission

    NASA Astrophysics Data System (ADS)

    Sato, Goro; Kokubun, Motohide; Nakazawa, Kazuhiro; Enoto, Teruaki; Fukazawa, Yasushi; Harayama, Atsushi; Hayashi, Katsuhiro; Kataoka, Jun; Katsuta, Junichiro; Kawaharada, Madoka; Laurent, Philippe; Lebrun, François; Limousin, Olivier; Makishima, Kazuo; Mizuno, Tsunefumi; Mori, Kunishiro; Nakamori, Takeshi; Noda, Hirofumi; Odaka, Hirokazu; Ohno, Masanori; Ohta, Masayuki; Saito, Shinya; Sato, Rie; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shinichiro; Terada, Yukikatsu; Uchiyama, Hideki; Uchiyama, Yasunobu; Watanabe, Shin; Yamaoka, Kazutaka; Yatsu, Yoichi; Yuasa, Takayuki

    2014-07-01

    The 6th Japanese X-ray satellite, ASTRO-H, is scheduled for launch in 2015. The hard X-ray focusing imaging system will observe astronomical objects with the sensitivity for detecting point sources with a brightness of 1/100,000 times fainter than the Crab nebula at > 10 keV. The Hard X-ray Imager (HXI) is a focal plane detector 12 m below the hard X-ray telescope (HXT) covering the energy range from 5 to 80 keV. The HXI is composed of a stacked Si/CdTe semiconductor detector module and surrounding BGO scintillators. The latter work as active shields for efficient reduction of background events caused by cosmic-ray particles, cosmic X-ray background, and in-orbit radiation activation. In this paper, we describe the detector system, and present current status of flight model development, and performance of HXI using an engineering model of HXI.

  8. Sorohalide scintillators, phosphors, and uses thereof

    DOEpatents

    Yang, Pin; Deng, Haoran; Doty, F. Patrick; Zhou, Xiaowang

    2016-05-10

    The present invention relates to sorohalide compounds having formula A.sub.3B.sub.2X.sub.9, where A is an alkali metal, B is a rare earth metal, and X is a halogen. Optionally, the sorohalide includes a dopant D. Such undoped and doped sorohalides are useful as scintillation materials or phosphors for any number of uses, including for radiation detectors, solid-state light sources, gamma-ray spectroscopy, medical imaging, and drilling applications.

  9. Nanophosphor composite scintillators comprising a polymer matrix

    DOEpatents

    Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David

    2010-11-16

    An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.

  10. A pixel unit-cell targeting 16 ns resolution and radiation hardness in a column read-out particle vertex detector

    SciTech Connect

    Wright, M.; Millaud, J.; Nygren, D.

    1992-10-01

    A pixel unit cell (PUC) circuit architecture, optimized for a column read out architecture, is reported. Each PUC contains an integrator, active filter, comparator, and optional analog store. The time-over-threshold (TOT) discriminator allows an all-digital interface to the array periphery readout while passing an analog measure of collected charge. Use of (existing) radiation hard processes, to build a detector bump-bonded to a pixel readout array, is targeted. Here, emphasis is on a qualitative explanation of how the unique circuit implementation benefits operation for Super Collider (SSC) detector application.

  11. Simulation of scintillation light output in LYSO scintillators through a full factorial design

    NASA Astrophysics Data System (ADS)

    Loignon-Houle, Francis; Bergeron, Mélanie; Pepin, Catherine M.; Charlebois, Serge A.; Lecomte, Roger

    2017-01-01

    Individually coupled scintillation detectors used in positron emission tomography (PET) imaging suffer from important signal losses due to the suboptimal light collection from crystals. As only a fraction of the light is generally extracted from long and thin scintillators, it is important to identify and understand the predominant causes of signal loss in order to eventually recover it. This simulation study investigates the multiple factors affecting the light transport in high-aspect ratio LYSO scintillators wrapped in specular reflectors through a full factorial design. By exploring various combinations of crystal geometry, readout conditions and wrapping conditions, it was found that an optimum light output can only be achieved through a careful selection of highly reflective material along with high-transmittance optical adhesive used to bond the reflector. Decreasing the adhesive thickness was also found to have a positive outcome in most explored configurations, however to a much lesser extent. Suboptimal reflectivity and adhesive transmittance also lead to an asymmetric light output distribution dependent on the depth of interaction of the radiation, potentially degrading energy resolution. By identifying the factors causing the most significant scintillation light losses through a factorial design, the most promising detector configurations have been identified in the quest for optimal light collection from scintillators.

  12. Novel method of producing nanoparticles for gadolinium-scintillator-based digital radiography.

    PubMed

    Lee, Young Kyu; Park, Sung Kwang; Shin, Jung Wook; Oh, Kyung Min; Heo, Seung Uk; Cho, Gyu Seok; Kim, Jin Young; Nam, Sang Hee

    2013-10-01

    Radiation image sensor properties affect the dose of radiation that patients are exposed to in a clinical setting. Numerous radiation imaging systems use scintillators as materials that absorb radiation. Rare-earth scintillators produced from elements such as gadolinium, yttrium, lutetium, and lanthanum have been investigated to improve the properties of radiation imaging systems. Although such rare-earth scintillators are manufactured with a bulk structure, they exhibit low resolution and low efficiency when they are used as conversion devices. Nanoscintillators have been proposed and researched as a possible solution to these problems. According to the research, the optical properties and size of fine scintillators are affected by the sintering temperature used to produce nanoscintillators instead of the existing bulk-structured scintillators. Therefore, the main purpose of this research is to develop radiation-imaging sensors based on nanoscintillators in order to evaluate the quantitative properties of various scintillators produced under various conditions such as sintering temperature. This is accomplished by measuring acquired phantom images, and modulation transfer functions (MTFs) for complementary-symmetry metal-oxide-semiconductor (CMOS) image sensors under the same X-ray conditions. Low-temperature solution combustion was used to produce fine scintillators consisting of 5 wt% of europium as an activator dopant in a Gd2O3 scintillator host. Variations in the characteristics of the fine scintillators were investigated. The characteristics of fine scintillators produced at various sintering temperatures (i.e., 600, 800, or 1000 degrees C) and with a europium concentration of 0.5 wt% were also analyzed to determine the optimal conditions for synthesizing the fine scintillators.

  13. Optimization of Shielded Scintillator for Neutron Detection

    NASA Astrophysics Data System (ADS)

    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.

  14. Test beam results with a sampling calorimeter of cerium fluoride scintillating crystals and tungsten absorber plates for calorimetry at the HL-LHC

    NASA Astrophysics Data System (ADS)

    Becker, R.; Dissertori, G.; Djambazov, L.; Donegà, M.; Dröge, M.; Haller, C.; Horisberger, U.; Lustermann, W.; Nessi-Tedaldi, F.; Quittnat, M.; Pandolfi, F.; Peruzzi, M.; Schönenberger, M.; Cavallari, F.; Dafinei, I.; Diemoz, M.; D`Imperio, G.; del Re, D.; Gelli, S.; Jorda Lope, C.; Meridiani, P.; Micheli, F.; Nuccetelli, M.; Organtini, G.; Paramatti, R.; Pellegrino, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Soffi, L.; Tabarelli de Fatis, T.; Martelli, A.; Monti, V.; Pastrone, N.; Trapani, P. P.; Candelise, V.; Della Ricca, G.

    2016-07-01

    A sampling calorimeter using cerium fluoride scintillating crystals as active material, interleaved with absorber plates made of tungsten, and read out by wavelength-shifting fibres has been tested with high-energy electron beams at the CERN SPS H4 beam line, as well as with lower-energy beams at the INFN Frascati Beam Test Facility in Italy. Energy resolution studies revealed a low stochastic term (< 10 % /√{ E }). This result, combined with high radiation hardness of the material used, marks this sampling calorimeter as a good candidate for the detectors' forward regions during the high luminosity phase of LHC.

  15. Development of scintillation materials for medical imaging and other applications

    SciTech Connect

    Melcher, C. L.

    2013-02-05

    Scintillation materials that produce pulses of visible light in response to the absorption of energetic photons, neutrons, and charged particles, are widely used in various applications that require the detection of radiation. The discovery and development of new scintillators has accelerated in recent years, due in large part to their importance in medical imaging as well as in security and high energy physics applications. Better understanding of fundamental scintillation mechanisms as well as the roles played by defects and impurities have aided the development of new high performance scintillators for both gamma-ray and neutron detection. Although single crystals continue to dominate gamma-ray based imaging techniques, composite materials and transparent optical ceramics potentially offer advantages in terms of both synthesis processes and scintillation performance. A number of promising scintillator candidates have been identified during the last few years, and several are currently being actively developed for commercial production. Purification and control of raw materials and cost effective crystal growth processes can present significant challenges to the development of practical new scintillation materials.

  16. Tests of the radiation hardness of VLSI Integrated Circuits and Silicon Strip Detectors for the SSC (Superconducting Super Collider) under neutron, proton, and gamma irradiation

    SciTech Connect

    Ziock, H.J.; Milner, C.; Sommer, W.F. ); Carteglia, N.; DeWitt, J.; Dorfan, D.; Hubbard, B.; Leslie, J.; O'Shaughnessy, K.F.; Pitzl, D.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E. . Inst. for Particle Physics); Ellison, J.A. ); Ferguson, P. ); Giubellino

    1990-01-01

    As part of a program to develop a silicon strip central tracking detector system for the Superconducting Super Collider (SSC) we are studying the effects of radiation damage in silicon detectors and their associated front-end readout electronics. We report on the results of neutron and proton irradiations at the Los Alamos National Laboratory (LANL) and {gamma}-ray irradiations at UC Santa Cruz (UCSC). Individual components on single-sided AC-coupled silicon strip detectors and on test structures were tested. Circuits fabricated in a radiation hard CMOS process and individual transistors fabricated using dielectric isolation bipolar technology were also studied. Results indicate that a silicon strip tracking detector system should have a lifetime of at least one decade at the SSC. 17 refs., 17 figs.

  17. Digital radiology using active matrix readout of amorphous selenium: radiation hardness of cadmium selenide thin film transistors.

    PubMed

    Zhao, W; Waechter, D; Rowlands, J A

    1998-04-01

    A flat-panel x-ray imaging detector using active matrix readout of amorphous selenium (a-Se) is being investigated for digital radiography and fluoroscopy. The active matrix consists of a two-dimensional array of thin film transistors (TFTs). Radiation penetrating through the a-Se layer will interact with the TFTs and it is important to ensure that radiation induced changes will not affect the operation of the x-ray imaging detector. The methodology of the present work is to investigate the effects of radiation on the characteristic curves of the TFTs using individual TFT samples made with cadmium selenide (CdSe) semiconductor. Four characteristic parameters, i.e., threshold voltage, subthreshold swing, field effect mobility, and leakage current, were examined. This choice of parameters was based on the well established radiation damage mechanisms for crystalline silicon metal-oxide-semiconductor field-effect transistors (MOSFETs), which have a similar principle of operation as CdSe TFTs. It was found that radiation had no measurable effect on the leakage current and the field effect mobility. However, radiation shifted the threshold voltage and increased the subthreshold swing. But even the estimated lifetime dose (50 Gy) of a diagnostic radiation detector will not affect the normal operation of an active matrix x-ray detector made with CdSe TFTs. The mechanisms of the effects of radiation will be discussed and compared with those for MOSFETs and hydrogenated amorphous silicon (a-Si:H) TFTs.

  18. Scintillator requirements for medical imaging

    SciTech Connect

    Moses, William W.

    1999-09-01

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

  19. An equatorial scintillation model

    NASA Astrophysics Data System (ADS)

    Fremouw, E. J.; Robins, R. E.

    1985-09-01

    Radiowave scintillation in the presence of natural and/or high altitude nuclear disturbances has the potential to disrupt numerous transionospheric radio and radar systems. This report develops a model characterizing the plasma density irregularities that produce scintillation in the naturally disturbed equatorial F layer. The model has been incorporated into Program WBMOD along with subroutines for computing both link geometry and scintillation indices, the latter by means of phase screen diffraction theory. The model is based on similarly extensive analysis of Wideband data from two equatorial stations. It describes irregularities at an effective height of 350 km that are isotropic across the geomagnetic field and elongated by a factor of 50 along the field and whose one dimensional spatial power spectrum obeys a single regime power law with a (negative) spectral index of 1.5. The height-integrated spectral strength of the irregularities is modeled as a function of solar epoch (sunspot number), the angle between the sunset terminator and the geomagnetic field line through the equatorial F layer point in question (a measure of seasonal and longitudinal variation), time after E-layer sunset on that field line, and the F-layer magnetic apex latitude of the point. The report also highlights a factor missing from complete characterization of the joint seasonal/longitudinal variation of scintillation, thought to depend upon thermospheric neutral winds.

  20. Quenching equation for scintillation

    NASA Astrophysics Data System (ADS)

    Kato, Takahisa

    1980-06-01

    A mathematical expression is postulated showing the relationship between counting rate and quenching agent concentration in a liquid scintillation solution. The expression is more suited to a wider range of quenching agent concentrations than the Stern-Volmer equation. An estimation of the quenched correction is demonstrated using the expression.

  1. X-ray emission from cataclysmic variables with accretion disks. I - Hard X-rays. II - EUV/soft X-ray radiation

    NASA Technical Reports Server (NTRS)

    Patterson, J.; Raymond, J. C.

    1985-01-01

    Theoretical models explaining the hard-X-ray, soft-X-ray, and EUV emission of accretion-disk cataclysmic variables in terms of the disk boundary layer (DBL) are developed on the basis of a survey of the published observational data. The data are compared with model predictions in graphs for systems with high or low (greater than or less than 10-Pg/s) accretion rates. Good agreement is obtained both at low accretion rates, where an optically thin rarefied hot (Te = 10 to the 8th K) DBL radiates most of its energy as hard X-rays, and at high accretion rates, where an optically thick 100,000-K DBL radiates most of its energy in the EUV and as soft X-rays. Detailed analysis of the old nova V603 Aql suggests that previous models predicting more detections of soft-X-ray/EUV emissions from thick-DBL objects (Ferland et al., 1982) used inappropriate dwarf masses, interstellar column densities, or classical-nova space densities.

  2. A radiation-hard dual-channel 12-bit 40 MS/s ADC prototype for the ATLAS liquid argon calorimeter readout electronics upgrade at the CERN LHC

    NASA Astrophysics Data System (ADS)

    Kuppambatti, J.; Ban, J.; Andeen, T.; Brown, R.; Carbone, R.; Kinget, P.; Brooijmans, G.; Sippach, W.

    2017-05-01

    The readout electronics upgrade for the ATLAS Liquid Argon Calorimeters at the CERN Large Hadron Collider requires a radiation-hard ADC. The design of a radiation-hard dual-channel 12-bit 40 MS/s pipeline ADC for this use is presented. The design consists of two pipeline A/D channels each with four Multiplying Digital-to-Analog Converters followed by 8-bit Successive-Approximation-Register analog-to-digital converters. The custom design, fabricated in a commercial 130 nm CMOS process, shows a performance of 67.9 dB SNDR at 10 MHz for a single channel at 40 MS/s, with a latency of 87.5 ns (to first bit read out), while its total power consumption is 50 mW/channel. The chip uses two power supply voltages: 1.2 and 2.5 V. The sensitivity to single event effects during irradiation is measured and determined to meet the system requirements.

  3. X-ray emission from cataclysmic variables with accretion disks. I - Hard X-rays. II - EUV/soft X-ray radiation

    NASA Technical Reports Server (NTRS)

    Patterson, J.; Raymond, J. C.

    1985-01-01

    Theoretical models explaining the hard-X-ray, soft-X-ray, and EUV emission of accretion-disk cataclysmic variables in terms of the disk boundary layer (DBL) are developed on the basis of a survey of the published observational data. The data are compared with model predictions in graphs for systems with high or low (greater than or less than 10-Pg/s) accretion rates. Good agreement is obtained both at low accretion rates, where an optically thin rarefied hot (Te = 10 to the 8th K) DBL radiates most of its energy as hard X-rays, and at high accretion rates, where an optically thick 100,000-K DBL radiates most of its energy in the EUV and as soft X-rays. Detailed analysis of the old nova V603 Aql suggests that previous models predicting more detections of soft-X-ray/EUV emissions from thick-DBL objects (Ferland et al., 1982) used inappropriate dwarf masses, interstellar column densities, or classical-nova space densities.

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

    SciTech Connect

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

    2010-09-01

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

  5. Investigating the Anisotropic Scintillation Response in Organic Crystal Scintillator Detectors

    NASA Astrophysics Data System (ADS)

    Schuster, Patricia Frances

    This dissertation presents several studies that experimentally characterize the scintillation anisotropy in organic crystal scintillators. These include measurements of neutron, gamma-ray and cosmic muon interactions in anthracene, a historical benchmark among organic scintillator materials, to confirm and extend measurements previously available in the literature. The gamma-ray and muon measurements provide new experimental confirmation that no scintillation anisotropy is present in their interactions. Observations from these measurements have updated the hypothesis for the physical mechanism that is responsible for the scintillation anisotropy concluding that a relatively high dE/dx is required in order to produce a scintillation anisotropy. The directional dependence of the scintillation output in liquid and plastic materials was measured to experimentally confirm that no scintillation anisotropy correlated to detector orientation exists in amorphous materials. These observations confirm that the scintillation anisotropy is not due to an external effect on the measurement system, and that a fixed, repeating structure is required for a scintillation anisotropy. The directional dependence of the scintillation output in response to neutron interactions was measured in four stilbene crystals of various sizes and growth-methods. The scintillation anisotropy in these materials was approximately uniform, indicating that the crystal size, geometry, and growth method do not significantly impact the effect. Measurements of three additional pure crystals and two mixed crystals were made. These measurements showed that 1) the magnitude of the effect varies with energy and material, 2) the relationship between the light output and pulse shape anisotropy varies across materials, and 3) the effect in mixed materials is very complex. These measurements have informed the hypothesis of the mechanism that produces the directional dependence. By comparing the various relationships

  6. Hardness testing

    SciTech Connect

    Not Available

    1987-01-01

    This technical manual is a handbook dealing with all aspects of hardness testing. Every hardness testing method is fully covered, from Rockwell to ultrasonic hardness testing. Specific hardness testing problems are also discussed, and methods are offered for many applications. One chapter examines how to select the correct hardness testing method. A directory of manufacturers, distributors and suppliers of hardness testing equipment and supplies in the United States and Canada is also included. The book consist of eight chapters and an appendix. It discusses common concepts of hardness, and the theories and methods of hardness testing. Coverage includes specific hardness testing methods - Brinell, Rockwell, Vickers, and microhardness testing; and other hardness testing methods, such as scleroscope, ultrasonic, scratch and file testing, and hardness evaluation by eddy current testing.

  7. Neutron detection with single crystal organic scintillators

    SciTech Connect

    Zaitseva, N; Newby, J; Hamel, S; Carman, L; Faust, M; Lordi, V; Cherepy, N; Stoeffl, W; Payne, S

    2009-07-15

    Detection of high-energy neutrons in the presence of gamma radiation background utilizes pulse-shape discrimination (PSD) phenomena in organics studied previously only with limited number of materials, mostly liquid scintillators and single crystal stilbene. The current paper presents the results obtained with broader varieties of luminescent organic single crystals. The studies involve experimental tools of crystal growth and material characterization in combination with the advanced computer modeling, with the final goal of better understanding the relevance between the nature of the organic materials and their PSD properties. Special consideration is given to the factors that may diminish or even completely obscure the PSD properties in scintillating crystals. Among such factors are molecular and crystallographic structures that determine exchange coupling and exciton mobility in organic materials and the impurity effect discussed on the examples of trans-stilbene, bibenzyl, 9,10-diphenylanthracene and diphenylacetylene.

  8. Codoped direct-gap semiconductor scintillators

    DOEpatents

    Derenzo, Stephen Edward [Pinole, CA; Bourret-Courchesne, Edith [Berkeley, CA; Weber, Marvin J [Danville, CA; Klintenberg, Mattias K [Berkeley, CA

    2008-07-29

    Fast, bright inorganic scintillators at room temperature are based on radiative electron-hole recombination in direct-gap semiconductors, e.g. CdS and ZnO. The direct-gap semiconductor is codoped with two different impurity atoms to convert the semiconductor to a fast, high luminosity scintillator. The codopant scheme is based on dopant band to dopant trap recombination. One dopant provides a significant concentration of carriers of one type (electrons or holes) and the other dopant traps carriers of the other type. Examples include CdS:In,Te; CdS:In,Ag; CdS:In,Na; ZnO:Ga,P; ZnO:Ga,N; ZnO:Ga,S; and GaN:Ge,Mg.

  9. Codoped direct-gap semiconductor scintillators

    DOEpatents

    Derenzo, Stephen E.; Bourret-Courchesne, Edith; Weber, Marvin J.; Klintenberg, Mattias K.

    2006-05-23

    Fast, bright inorganic scintillators at room temperature are based on radiative electron-hole recombination in direct-gap semiconductors, e.g. CdS and ZnO. The direct-gap semiconductor is codoped with two different impurity atoms to convert the semiconductor to a fast, high luminosity scintillator. The codopant scheme is based on dopant band to dopant trap recombination. One dopant provides a significant concentration of carriers of one type (electrons or holes) and the other dopant traps carriers of the other type. Examples include CdS:In,Te; CdS:In,Ag; CdS:In,Na; ZnO:Ga,P; ZnO:Ga,N; ZnO:Ga,S; and GaN:Ge,Mg.

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

    DOEpatents

    Ianakiev, Kiril D.; Hsue, Sin Tao; Browne, Michael C.; Audia, Jeffrey M.

    2006-07-25

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

  11. Hard x-ray scanning microscopy with coherent radiation: Beyond the resolution of conventional x-ray microscopes

    SciTech Connect

    Schropp, A.; Hoppe, R.; Patommel, J.; Samberg, D.; Seiboth, F.; Stephan, S.; Schroer, C. G.; Wellenreuther, G.; Falkenberg, G.

    2012-06-18

    We demonstrate x-ray scanning coherent diffraction microscopy (ptychography) with 10 nm spatial resolution, clearly exceeding the resolution limits of conventional hard x-ray microscopy. The spatial resolution in a ptychogram is shown to depend on the shape (structure factor) of a feature and can vary for different features in the object. In addition, the resolution and contrast are shown to increase with increasing coherent fluence. For an optimal ptychographic x-ray microscope, this implies a source with highest possible brilliance and an x-ray optic with a large numerical aperture to generate the optimal probe beam.

  12. Radiation Hard and Self Healing Substrate Agnostic Nanocrystalline ZnO Thin Film Electronics (Per5 E)

    DTIC Science & Technology

    2017-06-01

    radionuclides] 3.7 × 10 10 per second (s –1 ) [becquerel (Bq)] roentgen (R) [air exposure ] 2.579 760 × 10 –4 coulomb per kilogram (C kg –1 ) rad...shifts in threshold voltage and virtually no change in mobility as a function of 60Co gamma ray exposure . Dramatic recovery was observed after a short...For comparison, our early work is included in this figure showing the relatively high radiation tolerance of ZnO TFTs to radiation exposure . 0 200

  13. Composite scintillator screen

    DOEpatents

    Zeman, Herbert D.

    1994-01-01

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

  14. An Equatorial Scintillation Model

    DTIC Science & Technology

    1985-09-30

    been incor- porated into Program WBMOD along with subroutines for computing both link geometry and scintillation indices, the latter by means of...phase4screen diffraction theory. , Earlier versions of WBMOD , which are operational at USAF Global Weather Central and at several other user locations...which has been incorporated in WBMOD Version 8DI, is based on similarly extensive analysis of Wideband data from two equatorial stations. It describes

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

    SciTech Connect

    Vladimir Popov, Pavel Degtiarenko

    2011-06-01

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

  16. A theoretical study of CsI:Tl columnar scintillator image quality parameters by analytical modeling

    NASA Astrophysics Data System (ADS)

    Kalyvas, N.; Valais, I.; Michail, C.; Fountos, G.; Kandarakis, I.; Cavouras, D.

    2015-04-01

    Medical X-ray digital imaging systems such as mammography, radiography and computed tomography (CT), are composed from efficient radiation detectors, which can transform the X-rays to electron signal. Scintillators are materials that emit light when excited by X-rays and incorporated in X-ray medical imaging detectors. Columnar scintillator, like CsI:T1 is very often used for X-ray detection due to its higher performance. The columnar form limits the lateral spread of the optical photons to the scintillator output, thus it demonstrates superior spatial resolution compared to granular scintillators. The aim of this work is to provide an analytical model for calculating the MTF, the DQE and the emission efficiency of a columnar scintillator. The model parameters were validated against published Monte Carlo data. The model was able to predict the overall performance of CsI:Tl scintillators and suggested an optimum thickness of 300 μm for radiography applications.

  17. Hardness assurance testing and radiation hardening by design techniques for silicon-germanium heterojunction bipolar transistors and digital logic circuits

    NASA Astrophysics Data System (ADS)

    Sutton, Akil K.

    Hydrocarbon exploration, global navigation satellite systems, computed tomography, and aircraft avionics are just a few examples of applications that require system operation at an ambient temperature, pressure, or radiation level outside the range covered by military specifications. The electronics employed in these applications are known as "extreme environment electronics." On account of the increased cost resulting from both process modifications and the use of exotic substrate materials, only a handful of semiconductor foundries have specialized in the production of extreme environment electronics. Protection of these electronic systems in an extreme environment may be attained by encapsulating sensitive circuits in a controlled environment, which provides isolation from the hostile ambient, often at a significant cost and performance penalty. In a significant departure from this traditional approach, system designers have begun to use commercial off-the-shelf technology platforms with built in mitigation techniques for extreme environment applications. Such an approach simultaneously leverages the state of the art in technology performance with significant savings in project cost. Silicon-germanium is one such commercial technology platform that demonstrates potential for deployment into extreme environment applications as a result of its excellent performance at cryogenic temperatures, remarkable tolerance to radiation-induced degradation, and monolithic integration with silicon-based manufacturing. In this dissertation the radiation response of silicon-germanium technology is investigated, and novel transistor-level layout-based techniques are implemented to improve the radiation tolerance of HBT digital logic.

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

    SciTech Connect

    Bircher, Chad; Shao Yiping

    2012-02-15

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

  19. Neutron crosstalk between liquid scintillators

    SciTech Connect

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

    2015-05-01

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

  20. Neutron crosstalk between liquid scintillators

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  1. An analytical model of nonproportional scintillator light yield in terms of recombination rates

    SciTech Connect

    Bizarri, G.; Moses, W. W.; Singh, J.; Vasil'ev, A. N.; Williams, R. T.

    2009-02-15

    Analytical expressions for the local light yield as a function of the local deposited energy (-dE/dx) and total scintillation yield integrated over the track of an electron of initial energy E are derived from radiative and/or nonradiative rates of first through third order in density of electronic excitations. The model is formulated in terms of rate constants, some of which can be determined independently from time-resolved spectroscopy and others estimated from measured light yield efficiency as a constraint assumed to apply in each kinetic order. The rates and parameters are used in the theory to calculate scintillation yield versus primary electron energy for comparison to published experimental results on four scintillators. Influence of the track radius on the yield is also discussed. Results are found to be qualitatively consistent with the observed scintillation light yield. The theory can be applied to any scintillator if the rates of the radiative and nonradiative processes are known.

  2. Barium iodide and strontium iodide crystals andd scintillators implementing the same

    DOEpatents

    Payne, Stephen A; Cherepy, Nerine J; Hull, Giulia E; Drobshoff, Alexander D; Burger, Arnold

    2013-11-12

    In one embodiment, a material comprises a crystal comprising strontium iodide providing at least 50,000 photons per MeV. A scintillator radiation detector according to another embodiment includes a scintillator optic comprising europium-doped strontium iodide providing at least 50,000 photons per MeV. A scintillator radiation detector in yet another embodiment includes a scintillator optic comprising SrI.sub.2 and BaI.sub.2, wherein a ratio of SrI.sub.2 to BaI.sub.2 is in a range of between 0:1 A method for manufacturing a crystal suitable for use in a scintillator includes mixing strontium iodide-containing crystals with a source of Eu.sup.2+, heating the mixture above a melting point of the strontium iodide-containing crystals, and cooling the heated mixture near the seed crystal for growing a crystal. Additional materials, systems, and methods are presented.

  3. Proton-induced radioactivity in NaI (Tl) scintillation detectors

    NASA Technical Reports Server (NTRS)

    Fishman, G. J.

    1977-01-01

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

  4. Limits of scintillation materials for future experiments at high luminosity LHC and FCC

    NASA Astrophysics Data System (ADS)

    Korjik, M.

    2017-08-01

    This paper gives a summary of the systematic study of the radiation damage phenomena in scintillation materials which are caused by γ -quanta and energetic hadrons, the main contributors to the irradiation environment in further hadron collider experiments.

  5. The investigation of timing large area scintillation detectors with SiPM light sensors properties

    NASA Astrophysics Data System (ADS)

    Runtso, M. F.; Naumov, P. Yu; Naumov, P. P.; Maklyaev, E. F.; Kaplin, V. A.; Fomin, V. S.; Razzhivin, I. S.; Melikyan, Yu A.

    2017-01-01

    The timing large area plastic scintillation detectors with silicon photomultipliers as photosensors properties were investigated using a cosmic radiation at the ground level. Different techniques of the amplitude spectra and efficiency measurements were implemented. The measurements results are presented.

  6. Monitoring of I-125 contamination using a portable scintillation camera.

    PubMed

    Taylor, A; Verba, J W; Alazraki, N P; McCutchen, W C

    1978-04-01

    A technique has been developed using a portable scintillation camera to monitor I-125 contamination of personnel. The procedure takes less than a minute to complete and can detect 3 nanocuries; its use minimizes dissemination of I-125 throughout the hospital, emphasizes safe iodination practices and proper handling of radioactive materials, and reduces radiation exposure by undetected contamination.

  7. Thermal Radiometer Signal Processing Using Radiation Hard CMOS Application Specific Integrated Circuits for Use in Harsh Planetary Environments

    NASA Technical Reports Server (NTRS)

    Quilligan, G.; DuMonthier, J.; Aslam, S.; Lakew, B.; Kleyner, I.; Katz, R.

    2015-01-01

    Thermal radiometers such as proposed for the Europa Clipper flyby mission require low noise signal processing for thermal imaging with immunity to Total Ionizing Dose (TID) and Single Event Latchup (SEL). Described is a second generation Multi- Channel Digitizer (MCD2G) Application Specific Integrated Circuit (ASIC) that accurately digitizes up to 40 thermopile pixels with greater than 50 Mrad (Si) immunity TID and 174 MeV-sq cm/mg SEL. The MCD2G ASIC uses Radiation Hardened By Design (RHBD) techniques with a 180 nm CMOS process node.

  8. Thermal Radiometer Signal Processing using Radiation Hard CMOS Application Specific Integrated Circuits for use in Harsh Planetary Environments

    NASA Astrophysics Data System (ADS)

    Quilligan, G.; DuMonthier, J.; Aslam, S.; Lakew, B.; Kleyner, I.; Katz, R.

    2015-10-01

    Thermal radiometers such as proposed for the Europa Clipper flyby mission [1] require low noise signal processing for thermal imaging with immunity to Total Ionizing Dose (TID) and Single Event Latchup (SEL). Described is a second generation Multi- Channel Digitizer (MCD2G) Application Specific Integrated Circuit (ASIC) that accurately digitizes up to 40 thermopile pixels with greater than 50 Mrad (Si) immunity TID and 174 MeV-cm2/mg SEL. The MCD2G ASIC uses Radiation Hardened By Design (RHBD) techniques with a 180 nm CMOS process node.

  9. GPS Scintillation Analysis.

    DTIC Science & Technology

    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

  10. Scintillation detector for carbon-14

    NASA Technical Reports Server (NTRS)

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

    1971-01-01

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

  11. Hybrid scintillators for neutron discrimination

    DOEpatents

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

    2015-05-12

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

  12. Extruding plastic scintillator at Fermilab

    SciTech Connect

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

    2003-10-31

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

  13. Bread-Board Testing of the Radiation Hard Electron Monitor (RADEM) being developed for the ESA JUICE Mission

    NASA Astrophysics Data System (ADS)

    Mrigakshi, Alankrita; Hajdas, Wojtek; Marcinkowski, Radoslaw; Xiao, Hualin; Goncalves, Patricia; Pinto, Marco; Pinto, Costa; Marques, Arlindo; Meier, Dirk

    2016-04-01

    The RADEM instrument will serve as the radiation monitor for the JUICE spacecraft. It will characterize the highly dynamic radiation environment of the Jovian system by measuring the energy spectra of energetic electrons and protons up to 40 MeV and 250 MeV, respectively. It will also determine the directionality of 0.3-10 MeV electrons. Further goals include the detection of heavy ions, and the determination of the corresponding LET spectra and dose rates. Here, the tests of the Electron and Proton Telescopes, and the Directionality Detector of the RADEM Bread-Board model are described. The objective of these tests is to validate RADEM design and physical concept applied therein. The tests were performed at various irradiation facilities at the Paul Scherrer Institute (PSI) where energy ranges relevant for space applications can be covered (electrons: ≤100 MeV and protons: ≤230 MeV). The measured values are also compared with GEANT4 Monte-Carlo Simulation results.

  14. Development of a compact radiation-hardened low-noise front-end readout ASIC for CZT-based hard X-ray imager

    NASA Astrophysics Data System (ADS)

    Gao, W.; Gan, B.; Li, X.; Wei, T.; Gao, D.; Hu, Y.

    2015-04-01

    In this paper, we present the development and performances of a radiation-hardened front-end readout application-specific integrated circuit (ASIC) dedicated to CZT detectors for a hard X-ray imager in space applications. The readout channel consists of a charge sensitive amplifier (CSA), a CR-RC shaper, a fast shaper, a discriminator and a driving buffer. With the additional digital filtering, the readout channel can achieve very low noise performances and low power dissipation. An eight-channel prototype ASIC is designed and fabricated in 0.35 μm CMOS process. The energy range of the detected X-rays is evaluated as 1.45 keV to 281 keV. The gain is larger than 100 mV/fC. The equivalent noise charge (ENC) of the ASIC is 53 e- at zero farad plus 10 e- per picofarad. The power dissipation is less than 4.4 mW/channel. Through the measurement with a CZT detector, the energy resolution is less than 3.45 keV (FWHM) under the irradiation of the radioactive source 241Am. The radiation effect experiments indicate that the proposed ASIC can resist the total ionization dose (TID) irradiation of higher than 200 krad (Si).

  15. A system-level model for high-speed, radiation-hard optical links in HEP experiments based on silicon Mach-Zehnder modulators

    NASA Astrophysics Data System (ADS)

    Zeiler, M.; Detraz, S.; Olantera, L.; Sigaud, C.; Soos, C.; Troska, J.; Vasey, F.

    2016-12-01

    Silicon Mach-Zehnder modulators have been shown to be relatively insensitive to displacement damage beyond a 1-MeV-equivalent neutron fluence of 3ṡ1016n/cm2. Recent investigations on optimized device designs have also led to a high resistance against total ionizing dose levels of above 1 MGy. Such devices could potentially replace electrical and/or optical links close to the particle interaction points in future high energy physics experiments. Since they require an external continuous-wave light source, radiation-hard optical links based on silicon Mach-Zehnder modulators need to have a different system design when compared to existing directly modulated laser-based optical links. 10 Gb/s eye diagrams of irradiated Mach-Zehnder modulators were measured. The outcomes demonstrate the suitability for using these components in harsh radiation environments. A proposal for the implementation of silicon Mach-Zehnder modulators in CERN's particle detectors was developed and a model to calculate the system performance is presented. The optical power budget and the electrical power dissipation of the proposed link is compared to that of the upcoming Versatile Link system that will be installed in 2018.

  16. Thin GSO scintillator for neutron detection

    SciTech Connect

    Reeder, P.L.

    1994-05-01

    The new scintillator cerium-doped gadolinium orthosilicate (GSO -- Gd{sub 2}SiO{sub 5}:Ce) has a light output that is about 20% that of NaI(T1). The enormous cross section of Gd for capture of.thermal neutrons makes GSO a candidate for novel types of neutron.detectors. The characteristic radiations from neutron capture in Gd can be stopped in about 75 {mu}m of GSO. Data obtained from a GSO detector that was about 0.6-mm thick demonstrated that thermal neutrons could easily be detected and that higher energy gamma rays caused minimal interference.

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

    PubMed Central

    Bircher, Chad; Shao, Yiping

    2012-01-01

    Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators’ internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 × 1.5 and 2.0 × 2.0 mm2 cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be

  18. Development of the dual scintillator sheet and Phoswich detector for simultaneous Alpha- and Beta-rays measurement

    SciTech Connect

    Seo, B.K.; Kim, G.H.; Park, C.H.; Jung, Y.H.; Jung, C.H.; Lee, K.W.; Han, M.J.

    2007-07-01

    Thin sheet type of ZnS(Ag)/plastic dual scintillator for simultaneous counting of alpha- and beta-particles using a organic and inorganic scintillator widely used in the radiation measurement was manufactured, which could be applicable in the contamination monitoring systems. Counting materials were manufactured by solidification of the scintillator solution which mixed scintillator, solvent, and polymer. Prepared dual scintillator is a counting material which can simultaneously measure the alpha- and beta-particles. It was divided into two parts : an inorganic scintillator layer for alpha-particle detection and an organic one for beta-particle detection. The organic layer was composed of 2,5-diphenyloxazole [PPO] and 1,4,-bis[5-phenyl(oxazolyl)benzene] [POPOP] acting as the scintillator and polysulfone acting as the polymer. The inorganic layer was composed of ZnS(Ag) as scintillator and polysulfone as paste. The ZnS(Ag) scintillator layer was printed onto the organic layer using screen printing method. To estimate the detection ability of the prepared counting materials, alpha-particle emitting nuclide, Am-241, and beta emitting nuclide, Sr/Y-90, were used. The scintillations produced by interaction between radiation and scintillator were measured by photomultiplier tube. The overall counting results reveal that the developed detector is efficient for simultaneous counting of alpha- and beta-particles. For application test, the dual scintillator was fabricated with a Phoswich detector for monitoring the in-pipe alpha and beta contamination. To deploy inside a pipe, two types of Phoswich detectors, sheets and cylinders, were prepared. For in-pipe monitoring, it was found that the cylindrical type was excellent. In the study, polymer composite counting material and Phoswich detectors were prepared using organic and inorganic scintillator for detecting different radiations. In the future, it will be applied to the contamination monitoring system for nuclear

  19. Submicrometre beams from a hard X-ray waveguide at a third-generation synchrotron radiation source.

    PubMed

    Cedola, A; Lagomarsino, S; Di Fonzo, S; Jark, W; Riekel, C; Deschamps, P

    1998-01-01

    The use of an X-ray waveguide for scattering experiments at an undulator of a third-generation synchrotron radiation source is discussed. The performance with a perfect crystal monochromator, multilayer monochromator and focusing mirror is explored. A maximum flux of 8 x 109 photons s(-1) at lambda = 0.083 nm was obtained for a 0.15 (V) x 600 (H) micron(2) beam at the exit of the waveguide with a multilayer monochromator. The combination of an Si (111) monochromator and ellipsoidal mirror resulted in a flux of approximately 10(9) photons s(-1) but with a horizontal compression of the beam to approximately 30 micron. The use of the waveguide in diffraction experiments is addressed.

  20. Defect Antiperovskite Compounds Hg3Q2I2 (Q = S, Se, and Te) for Room-Temperature Hard Radiation Detection.

    PubMed

    He, Yihui; Kontsevoi, Oleg Y; Stoumpos, Constantinos C; Trimarchi, Giancarlo G; Islam, Saiful M; Liu, Zhifu; Kostina, Svetlana S; Das, Sanjib; Kim, Joon-Il; Lin, Wenwen; Wessels, Bruce W; Kanatzidis, Mercouri G

    2017-06-14

    The high Z chalcohalides Hg3Q2I2 (Q = S, Se, and Te) can be regarded as of antiperovskite structure with ordered vacancies and are demonstrated to be very promising candidates for X- and γ-ray semiconductor detectors. Depending on Q, the ordering of the Hg vacancies in these defect antiperovskites varies and yields a rich family of distinct crystal structures ranging from zero-dimensional to three-dimensional, with a dramatic effect on the properties of each compound. All three Hg3Q2I2 compounds show very suitable optical, electrical, and good mechanical properties required for radiation detection at room temperature. These compounds possess a high density (>7 g/cm(3)) and wide bandgaps (>1.9 eV), showing great stopping power for hard radiation and high intrinsic electrical resistivity, over 10(11) Ω cm. Large single crystals are grown using the vapor transport method, and each material shows excellent photo sensitivity under energetic photons. Detectors made from thin Hg3Q2I2 crystals show reasonable response under a series of radiation sources, including (241)Am and (57)Co radiation. The dimensionality of Hg-Q motifs (in terms of ordering patterns of Hg vacancies) has a strong influence on the conduction band structure, which gives the quasi one-dimensional Hg3Se2I2 a more prominently dispersive conduction band structure and leads to a low electron effective mass (0.20 m0). For Hg3Se2I2 detectors, spectroscopic resolution is achieved for both (241)Am α particles (5.49 MeV) and (241)Am γ-rays (59.5 keV), with full widths at half-maximum (FWHM, in percentage) of 19% and 50%, respectively. The carrier mobility-lifetime μτ product for Hg3Q2I2 detectors is achieved as 10(-5)-10(-6) cm(2)/V. The electron mobility for Hg3Se2I2 is estimated as 104 ± 12 cm(2)/(V·s). On the basis of these results, Hg3Se2I2 is the most promising for room-temperature radiation detection.