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.

Automated smear counting and data processing using a notebook computer in a biomedical research facility.

PubMed

Ogata, Y; Nishizawa, K

1995-10-01

An automated smear counting and data processing system for a life science laboratory was developed to facilitate routine surveys and eliminate human errors by using a notebook computer. This system was composed of a personal computer, a liquid scintillation counter and a well-type NaI(Tl) scintillation counter. The radioactivity of smear samples was automatically measured by these counters. The personal computer received raw signals from the counters through an interface of RS-232C. The software for the computer evaluated the surface density of each radioisotope and printed out that value along with other items as a report. The software was programmed in Pascal language. This system was successfully applied to routine surveys for contamination in our facility.

Spectrometer of high energy gamma quantums

NASA Technical Reports Server (NTRS)

Blokhintsev, I. D.; Melioranskiy, A. S.; Kalinkin, L. F.; Nagornykh, Y. I.; Pryakhin, Y. A.

1979-01-01

A detailed description of the apparatus GG-2M is given. The spectrometer contains a Cerenkov and scintillation (including anticoincidence) counter. The energies of the gamma quantums are measured by a shower calorimeter, in which scintillation counters are used in the capacity of detectors. Results are given for tuning the device on mu-mesons of cosmic rays. The data of physical tuning allow more reliable interpretation of the results of measurements which are received on the satellites.

Nuclear Forensics and Radiochemistry: Radiation Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rundberg, Robert S.

Radiation detection is necessary for isotope identification and assay in nuclear forensic applications. The principles of operation of gas proportional counters, scintillation counters, germanium and silicon semiconductor counters will be presented. Methods for calibration and potential pitfalls in isotope quantification will be described.

Scintillator fiber optic long counter

DOEpatents

McCollum, Tom; Spector, Garry B.

1994-01-01

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

The response of a scintillation counter below an emulsion chamber to heavy nucleus interactions in the chamber

NASA Technical Reports Server (NTRS)

Burnett, T. H.; Dake, S.; Derrickson, J. H.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Hayashi, T.; Holynski, R.; Iwai, J.;

A broad band X-ray imaging spectrophotometer for astrophysical studies

NASA Technical Reports Server (NTRS)

Lum, Kenneth S. K.; Lee, Dong Hwan; Ku, William H.-M.

1988-01-01

A broadband X-ray imaging spectrophotometer (BBXRIS) has been built for astrophysical studies. The BBXRIS is based on a large-imaging gas scintillation proportional counter (LIGSPC), a combination of a gas scintillation proportional counter and a multiwire proportional counter, which achieves 8 percent (FWHM) energy resolution and 1.5-mm (FWHM) spatial resolution at 5.9 keV. The LIGSPC can be integrated with a grazing incidence mirror and a coded aperture mask to provide imaging over a broad range of X-ray energies. The results of tests involving the LIGSPC and a coded aperture mask are presented, and possible applications of the BBXRIS are discussed.

Search for 1/3e and 2/3e charged quarks in the cosmic radiation at 2750-m altitude.

NASA Technical Reports Server (NTRS)

Cox, A. J.; Beauchamp, W. T.; Bowen, T.; Kalbach, R. M.

1972-01-01

A scintillation counter telescope consisting of eight liquid scintillation counters and four wide-gap spark chambers was used to search for particles with electric charge 1/3e and 2/3e in cosmic rays at 2750 m above sea level. No such particles were detected during the 1500-hr experimental run. Upper limits on the vertical fluxes are established, and estimates of the corresponding sea-level fluxes are made for comparison with previous results.

Scintillator fiber optic long counter

DOEpatents

McCollum, T.; Spector, G.B.

1994-03-29

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

RADIATION COUNTER

DOEpatents

Goldsworthy, W.W.

1958-02-01

This patent relates to a radiation counter, and more particularly, to a scintillation counter having high uniform sensitivity over a wide area and capable of measuring alpha, beta, and gamma contamination over wide energy ranges, for use in quickly checking the contami-nation of personnel. Several photomultiplier tubes are disposed in parallel relationship with a light tight housing behind a wall of scintillation material. Mounted within the housing with the photomultipliers are circuit means for producing an audible sound for each pulse detected, and a range selector developing a voltage proportional to the repetition rate of the detected pulses and automatically altering its time constant when the voltage reaches a predetermined value, so that manual range adjustment of associated metering means is not required.

Fast scintillation counter system and performance

NASA Technical Reports Server (NTRS)

Sasaki, H.; Nishioka, A.; Ohmori, N.; Kusumose, M.; Nakatsuka, T.; Horiki, T.; Hatano, Y.

1985-01-01

An experimental study of the fast scintillation counter (FS) system to observe a shower disk structure at Mt. Norikura is described, especially the system performance and a pulse wave-form by a single charge particles. The photomultiplier tube (PT) pulse appears at the leading edge of the main pulse. To remove this PT-pulse from the main pulse, the frame of the scintillator vessel was changed. The fast triggering system was made to decrease the dead time which came from the use of the function of the self triggering of the storage oscilloscope (OSC). To provide a new field on the multi-parameter study of the cosmic ray showers, the system response of the FS system also improved as a result of many considerations.

Development and Testing of Scintillating Detectors for the Muon g-2 Experiment

NASA Astrophysics Data System (ADS)

Martinez, Benjamin; Diamond, Edward; Sblendorio, Alec; Gray, Frederick

2016-09-01

The precise value of the muon's anomalous magnetic moment that was measured at Brookhaven National Laboratory E821 differed by more than three standard deviations from predictions of the Standard Model. The Muon g-2 Experiment at Fermilab will attain a more precise measurement by a factor of three by observing the muon spin precession frequency in a magnetic field. This improved measurement could lead to evidence of physics beyond the Standard Model. A thin-scintillator entrance (T0) counter prototype is being tested for possible use in the experiment to determine the intensity and temporal profile of the beam as it is injected into the muon storage ring. The counter is also being evaluated to determine whether it can monitor undesired particles that arrive after the main beam pulse. The unique design of the entrance counter uses a silicon photomultiplier to read the light output from a scintillator. The progress of the design of the T0 entrance counter along with the results of light output tests from a beta source and the SLAC high-energy electron beam are the primary foci of this presentation. The status of scintillating fiber harp beam monitor detectors that will also be used in the g-2 Experiment to detect the position and width of the muon beam will also be presented. This material is based upon work supported by the National Science Foundation under Grant No. PHY-1505887.

Microprocessor-based single particle calibration of scintillation counter

NASA Technical Reports Server (NTRS)

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

1985-01-01

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

A logarithmic detection system suitable for a 4π array

NASA Astrophysics Data System (ADS)

Westfall, G. D.; Yurkon, J. E.; van der Plicht, J.; Koenig, Z. M.; Jacak, B. V.; Fox, R.; Crawley, G. M.; Maier, M. R.; Hasselquist, B. E.; Tickle, R. S.; Horn, D.

1985-08-01

A low pressure multiwire proportional counter, a Bragg curve counter, and an array of CaF2/plastic scintillator telescopes have been developed in a geometry suitable for close packing into a 4π detector designed to study nucleus-nucleus reactions at 100-200 MeV/nucleon. The multiwire counter is hexagonal in shape and gives X-Y position information using resistive charge division from nichrome-coated stretched polypropylene foils. The Bragg curve counter is a hexagonal pyramid with the charge taken from a Frisch gridded anode. A field shaping grid gives the Bragg curve counter a radial field. The scintillator telescopes are shaped as truncated triangular pyramids such that when stacked together they form a truncated hexagonal pyramid. The light signal of the CaF2-plastic combination is read with one phototube using a phoswich technique to separate the ΔE signal from the E signal. The entire system has been tested so far for particles with 1 <= Z <= 18 and gives good position, charge, and time resolution.

Forward shower counters for diffractive physics at the LHC

NASA Astrophysics Data System (ADS)

Albrow, Michael; Collins, Paula; Penzo, Aldo

2014-11-01

The LHC detectors have incomplete angular coverage in the forward direction, for example in the region 6 ≲ |η| ≲ 8, which can be improved with the addition of simple scintillation counters around the beam pipes about 50 m to 120 m from the intersection point. These counters detect showers created by particles hitting the beam pipes and nearby material. The absence of signals in these counters in low pileup conditions is an indication of a forward rapidity gap as a signature of diffraction. In addition, they can be used to detect hadrons from low mass diffractive excitations of the proton, not accompanied by a leading proton but adjacent to a rapidity gap over (e.g.) 3 ≲ |η| ≲ 6. Such a set of forward shower counters, originally used at CDF, was used in CMS (FSC) for high-β* running with TOTEM during LHC Run-1. During LS1 the CMS FSC system is being upgraded for future low pileup runs. A similar system, called HERSCHEL is being installed in LHCb. ALICE is implementing scintillation counters, ADA and ADC, with 4.5 ≲ |η| ≲ 6.4.

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

NASA Technical Reports Server (NTRS)

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

1986-01-01

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

A high resolution gas scintillation proportional counter for studying low energy cosmic X-ray sources

NASA Technical Reports Server (NTRS)

Hamilton, T. T.; Hailey, C. J.; Ku, W. H.-M.; Novick, R.

1980-01-01

In recent years much effort has been devoted to the development of large area gas scintillation proportional counters (GSPCs) suitable for use in X-ray astronomy. The paper deals with a low-energy GSPC for use in detecting sub-keV X-rays from cosmic sources. This instrument has a measured energy resolution of 85 eV (FWHM) at 149 eV over a sensitive area of 5 sq cm. The development of imaging capability for this instrument is discussed. Tests are performed on the feasibility of using an arrangement of several phototubes placed adjacent to one another to determine event locations in a large flat counter. A simple prototype has been constructed and successfully operated.

RADIOMETRIC EQUIPMENT ON SECOND SPACESHIP-SATELLITE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papkov, S.F.; Pisarenko, N.F.; Savenko, I.A.

1961-01-01

Equipment installed on the second Soviet spaceshipsatellite to measure radiation and determine dose absorption is described. A scintillation counter recorded charged particles penetrating the skin of the spaceship and gamma quanta with energies exceeding 25 kev. Two CTC-5 gas-discharge counters also recorded charged particles, and, as the efficiency of gamma recording was low (below 10/sup -2/), a comparison of readings made it possible to evaluate the contribution of the charged particles and the gamma quanta, respectively, to the absorbed dose. A separate scintillation counter measured the energy flow of relatively soft charged particles. Electronic equipment was supplied with energy frommore » a 6( plus or minus 1)-v battery with power not over 0.5 w. A thorough check of the spaceship after its return to earth demonstrated that all the counters and electronie devices had retained their efficiency. A block diagram of the equipment is given. (OTS)« less

[Low level alpha activity measurements with pulse shape discrimination--application to the determination of alpha-nuclides in environmental samples].

PubMed

Satoh, K; Noguchi, M; Higuchi, H; Kitamura, K

1984-12-01

Liquid scintillation counting of alpha rays with pulse shape discrimination was applied to the analysis of 226Ra and 239+240Pu in environmental samples and of alpha-emitters in/on a filter paper. The instrument used in this study was either a specially designed detector or a commercial liquid scintillation counter with an automatic sample changer, both of which were connected to the pulse shape discrimination circuit. The background counting rate in alpha energy region of 5-7 MeV was 0.01 or 0.04 cpm/MeV, respectively. The figure of merit indicating the resolving power for alpha- and beta-particles in time spectrum was found to be 5.7 for the commercial liquid scintillation counter.

DOSIMETRIC MEASUREMENTS ON THE SECOND SOVIET SPACESHIP SATELLITE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savenko, I.A.; Pisarenko, N.F.; Shavrin, P.I.

1963-02-01

Readings of counters placed inside Sputnik II are given for one portion of its trajectory. The readings were taken by a gas-discharge counter STS-5 and a NaI crystal scintillator counter that registered gamma quanta, charged particles with a 25-kev counting threshold, and the aggregate energy liberation of ionizing radiations in the crystal. (C.E.S.)

Preparation of paper scintillator for detecting 3H contaminant.

PubMed

Miyoshi, Hirokazu; Ikeda, Toshiji

2013-09-01

Liquid scintillator (LS)-encapsulated silica was prepared by the sol-gel method and then was added dropwise onto a wipe paper to form a paper scintillator. First, the efficiencies of wipe were determined for both the paper scintillator and the wipe paper using a liquid scintillation counter (LSC). The efficiencies of wipe using the paper scintillator and the wipe paper were 88 and 36 %, respectively. The detection efficiencies were 5.5 % for the paper scintillator, 46 % for the wipe paper using an LS and 0.08 % for the (3)H/(14)C survey meter, respectively, compared with that of a melt-on scintillator of 47 %. Second, an (3)H contaminant on the paper scintillator was successfully detected using a photomultiplier without an LSC or an (3)H/(14)C survey meter. Finally, the paper scintillator was able to detect beta rays of the (3)H contaminant easily without an LS.

Radiometric liquid level gauge with linear-detection (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glaeser, M.; Emmelmann, K.P.

1973-09-01

A description is given of a radiometric liquid level gauge with linear detection. It consists of a set of radioactive sources (e.g., /sup 137/Cs) with quadratic graduation in their activities, of a scintillation counter with electronic back-up unit and of a slender tube. The tube, sources and scintillation counter form a compact snd easily transportsble liquid level gauge. It is-especially adapted for liquid level measurements in slender, difficulty accessible and opaque containers. The device supplements the different methods for liquid level measurement with a new variant which is adopted for many cases in practice. (auth)

Nuclear Science Symposium, 21st, Scintillation and Semiconductor Counter Symposium, 14th, and Nuclear Power Systems Symposium, 6th, Washington, D.C., December 11-13, 1974, Proceedings

NASA Technical Reports Server (NTRS)

1975-01-01

Papers are presented dealing with latest advances in the design of scintillation counters, semiconductor radiation detectors, gas and position sensitive radiation detectors, and the application of these detectors in biomedicine, satellite instrumentation, and environmental and reactor instrumentation. Some of the topics covered include entopistic scintillators, neutron spectrometry by diamond detector for nuclear radiation, the spherical drift chamber for X-ray imaging applications, CdTe detectors in radioimmunoassay analysis, CAMAC and NIM systems in the space program, a closed loop threshold calibrator for pulse height discriminators, an oriented graphite X-ray diffraction telescope, design of a continuous digital-output environmental radon monitor, and the optimization of nanosecond fission ion chambers for reactor physics. Individual items are announced in this issue.

Half-life measurement of 212Pb by means of a liquid scintillator-based 220Rn trap.

PubMed

Kossert, Karsten

2017-07-01

A beaker was filled with a liquid mineral oil scintillator to catch 220 Rn from a 228 Th source. The liquid scintillator was then transferred to a polyethylene vial which was measured in a custom-built triple-to-double coincidence ratio (TDCR) counter. The measurements were used to determine the 212 Pb half-life which was found to be 10.622(7) hours. Copyright © 2017 Elsevier Ltd. All rights reserved.

Safeguards Technology Development Program 1st Quarter FY 2018 Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prasad, Manoj K.

LLNL will evaluate the performance of a stilbene-based scintillation detector array for IAEA neutron multiplicity counting (NMC) applications. This effort will combine newly developed modeling methodologies and recently acquired high-efficiency stilbene detector units to quantitatively compare the prototype system performance with the conventional He-3 counters and liquid scintillator alternatives.

CALCIUM ABSORPTION IN MAN: BASED ON LARGE VOLUME LIQUID SCINTILLATION COUNTER STUDIES.

PubMed

LUTWAK, L; SHAPIRO, J R

1964-05-29

A technique has been developed for the in vivo measurement of absorption of calcium in man after oral administration of 1 to 5 microcuries of calcium-47 and continuous counting of the radiation in the subject's arm with a large volume liquid scintillation counter. The maximum value for the arm counting technique is proportional to the absorption of tracer as measured by direct stool analysis. The rate of uptake by the arm is lower in subjects with either the malabsorption syndrome or hypoparathyroidism. The administration of vitamin D increases both the absorption rate and the maximum amount of calcium absorbed.

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

NASA Technical Reports Server (NTRS)

Link, Jason

2011-01-01

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erchinger, J. L.; Orrell, John L.; Aalseth, C. E.

The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3–3600 keV can be realized. Finally, initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.

Measurement of tritium in natural water

NASA Astrophysics Data System (ADS)

Li, Meifen

1985-06-01

A detergent-scintillation liquid mixture applied to measure low specific activity of tritium in natural water was studied. The DYS-1 low level liquid scintillation counter designed and manufactured by our institute was employed. In comparing the Triton X-100 scintillation liquid mixture with the dioxane-based-scintillation liquid, a better formula for Triton X-100 scintillation liquid mixture was determined, the mixture possesses the quality of high water content; high efficiency and low back-ground in measuring tritium in water. Chemiluminescence of the Triton X-100 scintillation liquid mixture can be totally de-excited in short time. It can be employed at ambient temperature 11 28°C. For 20ml sample in quartz vials, counting efficiency is 15% with a background 2.17 cpm, Y=31 TU (t=30 min).

Electron Calorimeter Experiment

NASA Technical Reports Server (NTRS)

Adams, James H.

2008-01-01

Boron loaded scintillators are suitable for measuring secondary neutrons produced by high-energy particles: protons & electrons Neutron flux can be used to discriminate hadron and electro-magnetic particles Combined effectiveness of all e/p discriminators techniques employedTBD Only moderate improvement in detection efficiency for B-10 concentrations >few% in thick moderators Bottom scintillator might serve as cascade penetration counter (TBC)

An instrument to measure the spectrum of cosmic ray iron and other nuclei to above 100 GeV-nucleon

NASA Technical Reports Server (NTRS)

Arens, J. F.; Balasubrahmanyan, V. K.; Ormes, J. F.; Siohan, F.; Schmidt, W. K. H.; Simon, M.; Spiegelhauer, H.

1978-01-01

A balloon-borne detector system for extending the study of cosmic ray composition to the energy region beyond 100 GeV/nucleon is described. The instrument incorporates an ionization calorimeter and a gas Cherenkov counter filled with freon for the determination of energies, and a charge module, consisting of scintillation and a lucite Cherenkov counter, for determining the charge of the incoming particle. The scintillators were utilized to determine the position of the incoming particle in addition to its charge. The characteristics of these detectors with respect to resolution, and the methods employed in laboratory calibration, cross-checks with flight data and actual performance in the flights are described in detail. Monte Carlo simulation of the ionization calorimeter and comparison of the response of the calorimeter and gas Cherenkov counter for complex nuclei was used to convert the observed calorimeter signal to absolute energy in a consistent manner.

Real-time analysis of endosomal lipid transport by live cell scintillation proximity assay

PubMed Central

Stockinger, Walter; Castoreno, Adam B.; Wang, Yan; Pagnon, Joanne C.; Nohturfft, Axel

2007-01-01

A scintillation proximity assay has been developed to study the endosomal trafficking of radiolabeled cholesterol in living cells. Mouse macrophages were cultured in the presence of tritiated cholesterol and scintillant microspheres. Microspheres were taken up by phagocytosis and stored in phagolysosomes. Absorption of tritium β particles by the scintillant produces light signals that can be measured in standard scintillation counters. Because of the short range of tritium β particles and for geometric reasons, scintillant microspheres detect only that fraction of tritiated cholesterol localized inside phagolysosomes or within a distance of ~600 nm. By incubating cultures in a temperature-controlled microplate reader, the kinetics of phagocytosis and cholesterol transport could be analyzed in near-real time. Scintillation signals were significantly increased in response to inhibitors of lysosomal cholesterol export. This method should prove a useful new tool for the study of endosomal trafficking of lipids and other molecules. PMID:15314094

Measurement of the time resolution of small SiPM-based scintillation counters

NASA Astrophysics Data System (ADS)

Kravchenko, E. A.; Porosev, V. V.; Savinov, G. A.

2017-12-01

In this research, we evaluated the timing resolution of SiPM-based scintillation detector on a 1-GeV electron beam "extracted" from VEPP-4M. We tested small scintillation crystals of pure CsI, YAP, LYSO, and LFS-3 with HAMAMATSU S10362-33-025C and S13360-3050CS. The CsI scintillator together with HAMAMATSU S13360-3050CS demonstrated the best results. Nevertheless, the achieved time resolution of ~80 ps (RMS) relates mainly to the photodetector itself. It makes the silicon photomultiplier an attractive candidate to replace other devices in applications where sub-nanosecond accuracy is required.

A study of time over threshold (TOT) technique for plastic scintillator counter

NASA Astrophysics Data System (ADS)

Wu, Jin-Jie; Heng, Yue-Kun; Sun, Zhi-Jia; Wu, Chong; Zhao, Yu-Da; Yang, Gui-An; Jiang, Chun-Hua

2008-03-01

A new charge measurement method, time over threshold (TOT), has been used in some gas detectors lately. Here TOT is studied for TOF system, made of plastic scintillator counter, which can simplify the electronics of the system. The signal characteristics are measured and analyzed with a high quality oscilloscope, including noise, pedestal, signal amplitude, total charge, rise time and the correlation between them. The TOT and charge are related and can be fitted by some empirical formula. The charge measurement resolution by TOT is given and this will help the design of TOF electronics. Supported by BEPCII Project, CAS Knowledge Innovation Program U602 and U-34 (IHEP)

Development of an Ultra-Low Background Liquid Scintillation Counter for Trace Level Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erchinger, Jennifer L.; Orrell, John L.; Aalseth, Craig E.

2015-09-01

Low-level liquid scintillation counting (LSC) has been established as one of the radiation detection techniques useful in elucidating environmental processes and environmental monitoring around nuclear facilities. The Ultra-Low Background Liquid Scintillation Counter (ULB-LSC) under construction in the Shallow Underground Laboratory at Pacific Northwest National Laboratory aims to further reduce the MDAs and/or required sample processing. Through layers of passive shielding in conjunction with an active veto and 30 meters water equivalent overburden, the background reduction is expected to be 10 to 100 times below typical analytic low-background liquid scintillation systems. Simulations have shown an expected background of around 14 countsmore » per day. A novel approach to the light collection will use a coated hollow light guide cut into the inner copper shielding. Demonstration LSC measurements will show low-energy detection, spectral deconvolution, and alpha/beta discrimination capabilities, from trials with standards of tritium, strontium-90, and actinium-227, respectively. An overview of the system design and expected demonstration measurements will emphasize the potential applications of the ULB-LSC in environmental monitoring for treaty verification, reach-back sample analysis, and facility inspections.« less

СЦИНТИЛЛЯЦИОННЫЕ ДЕТЕКТОРЫ УСТАНОВКИ CDF П В ЭКСПЕРИМЕНТАХ ПО ФИЗИКЕ ТЯЖЁЛЫХ КВАРКОВ НА ТЭВА ТРОНЕ (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chokheli, Davit

2007-01-01

The author presents the following: 1) Development and creation from scratch of scintillation detectors system for CDF II muon trigger using more than 1140 scintillation counters different type and size; development of the contol and monitoring software/hardware systems; 2) Development and creation of updgraded preshower CPR II for electromagnet calorimeter CDF II with better segmentation by pseydorapidity (10 times more against previous version) to be able collect the data with increased Tevatron luminosity; 3) Aging study for scintillation counters used at CDF II and its long-term efficiency estimation; and 4) Research of the possibility to use the proposed new muon trigger atmore » $$1.0 \\leq \\mu \\leq 1.25$$ region by pseudorapidity by creation of additional layers of muon scintillation detectors.« less

GASEOUS SCINTILLATION COUNTER

DOEpatents

Eggler, C.; Huddleston, C.M.

1959-04-28

A gaseous excitation counter for detecting the presence amd measuring the energy of subatomic particles and electromagnetic radiation is described. The counter includes a gas-tight chamber filled with an elemental gas capable of producing ultra-violet excitation quanta when irradiated with subatomic particles and electromagnetic radiation. The gas has less than one in a thousand parts ultra-violet absorbing contamination. When nuclear radiation ps present the ultra-violet light produced by the gas strikes a fluorescent material within the counter, responsive to produce visible excitation quanta, and photo-sensitive counting means detect the visible emission.

Receptor binding assay for paralytic shellfish poisoning toxins: optimization and interlaboratory comparison.

PubMed

Ruberu, Shryamalie R; Liu, Yun-Gang; Wong, Carolyn T; Perera, S Kusum; Langlois, Gregg W; Doucette, Gregory J; Powell, Christine L

2003-01-01

A receptor binding assay (RBA) for detection of paralytic shellfish poisoning (PSP) toxins was formatted for use in a high throughput detection system using microplate scintillation counting. The RBA technology was transferred from the National Ocean Service, which uses a Wallac TriLux 1450 MicroBeta microplate scintillation counter, to the California Department of Health Services, which uses a Packard TopCount scintillation counter. Due to differences in the detector arrangement between these 2 counters, markedly different counting efficiencies were exhibited, requiring optimization of the RBA protocol for the TopCount instrument. Precision, accuracy, and sensitivity [limit of detection = 0.2 microg saxitoxin (STX) equiv/100 g shellfish tissue] of the modified protocol were equivalent to those of the original protocol. The RBA robustness and adaptability were demonstrated by an interlaboratory study, in which STX concentrations in shellfish generated by the TopCount were consistent with MicroBeta-derived values. Comparison of STX reference standards obtained from the U.S. Food and Drug Administration and the National Research Council, Canada, showed no observable differences. This study confirms the RBA's value as a rapid, high throughput screen prior to testing by the conventional mouse bioassay (MBA) and its suitability for providing an early warning of increasing PSP toxicity when toxin levels are below the MBA limit of detection.

Prototype apparatus for the measurement of tritium in expired air using plastic scintillator pellets.

PubMed

Furuta, Etsuko; Ito, Takeshi

2018-02-01

A new apparatus for measuring tritiated water in expired air was developed using plastic scintillator (PS) pellets and a low-background liquid scintillation counter. The sensitivity of the apparatus was sufficient when a large adapted Teflon vial was used. The measurement method generated low amounts of organic waste because the PS pellets were reusable by rinsing, and had adequate detection limits. The apparatus is useful for the safety management of workers that are exposed to radioactive materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance and field tests of a handheld Compton camera using 3-D position-sensitive scintillators coupled to multi-pixel photon counter arrays

NASA Astrophysics Data System (ADS)

Kishimoto, A.; Kataoka, J.; Nishiyama, T.; Fujita, T.; Takeuchi, K.; Okochi, H.; Ogata, H.; Kuroshima, H.; Ohsuka, S.; Nakamura, S.; Hirayanagi, M.; Adachi, S.; Uchiyama, T.; Suzuki, H.

2014-11-01

After the nuclear disaster in Fukushima, radiation decontamination has become particularly urgent. To help identify radiation hotspots and ensure effective decontamination operation, we have developed a novel Compton camera based on Ce-doped Gd3Al2Ga3O12 scintillators and multi-pixel photon counter (MPPC) arrays. Even though its sensitivity is several times better than that of other cameras being tested in Fukushima, we introduce a depth-of-interaction (DOI) method to further improve the angular resolution. For gamma rays, the DOI information, in addition to 2-D position, is obtained by measuring the pulse-height ratio of the MPPC arrays coupled to ends of the scintillator. We present the detailed performance and results of various field tests conducted in Fukushima with the prototype 2-D and DOI Compton cameras. Moreover, we demonstrate stereo measurement of gamma rays that enables measurement of not only direction but also approximate distance to radioactive hotspots.

PHOTON STUDY WITH SPUTNIK III

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chudakov, A.E.

1961-01-01

>A scintillation counter with twice the efficiency of a Geiger counter for photon recording was placed in the third Soviet satellite. The counter consisted of a cylindrical crystal of sodium iodide and a photomuitiplier. It was found that the total ionization in the crystal was much greater than expected. This excess seemed to depend on geomagnetic longitude as well as latitude. The most probable explanation is the bremsstrahlung radiation of electrons of energy less than 100 kev. (L.N.N.)

An alpha–gamma coincidence spectrometer based on the Photon–Electron Rejecting Alpha Liquid Scintillation (PERALS®) system

DOE PAGES

Cadieux, J. R.; Fugate, G. A.; King, III, G. S.

2015-02-07

Here, an alpha–gamma coincidence spectrometer has been developed for the measurement of selected actinide isotopes in the presence of high beta/gamma fields. The system is based on a PERALS® liquid scintillation counter for beta/alpha discrimination and was successfully tested with both high purity germanium and bismuth germanate, gamma-ray detectors using conventional analog electronics.

A High-Energy Focal-Plane Gas Scintillation Proportional Counter

NASA Technical Reports Server (NTRS)

Ramsey, B. D.; Austin, R. A.; Apple, J. A.; Dietz, K. L.

1999-01-01

We have developed a high-pressure Gas Scintillation Proportional Counter (GSPC) for the focus of a hard-x-ray telescope. It features an absorption region 50 mm in diameter and 50 mm deep, filled with Xenon + 4% He at 10(exp 6) Pa total pressure, which gives useful response (greater than 75% efficiency) up to the mirror cut-off of 70 keV. Tests with a prototype unit show an energy resolution of 3.5% at 60 keV and a spatial resolution of 0.35 mm from 30-50 keV. Two flight units are currently under construction for a balloon flight in September 1999. Full details of their design and performance will be presented together with available quick-look background data from the flight.

Optimization of liquid scintillation measurements applied to smears and aqueous samples collected in industrial environments

NASA Astrophysics Data System (ADS)

Chapon, Arnaud; Pigrée, Gilbert; Putmans, Valérie; Rogel, Gwendal

Search for low-energy β contaminations in industrial environments requires using Liquid Scintillation Counting. This indirect measurement method supposes a fine control from sampling to measurement itself. Thus, in this paper, we focus on the definition of a measurement method, as generic as possible, for both smears and aqueous samples' characterization. That includes choice of consumables, sampling methods, optimization of counting parameters and definition of energy windows, using the maximization of a Figure of Merit. Detection limits are then calculated considering these optimized parameters. For this purpose, we used PerkinElmer Tri-Carb counters. Nevertheless, except those relative to some parameters specific to PerkinElmer, most of the results presented here can be extended to other counters.

Active Well Counting Using New PSD Plastic Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hausladen, Paul; Newby, Jason; McElroy, Robert Dennis

This report presents results and analysis from a series of proof-of-concept measurements to assess the suitability of segmented detectors constructed from Eljen EJ-299-34 PSD-plastic scintillator with pulse-shape discrimination capability for the purposes of quantifying uranium via active neutron coincidence counting. Present quantification of bulk uranium materials for international safeguards and domestic materials control and accounting relies on active neutron coincidence counting systems, such as the Active Well Coincidence Counter (AWCC) and the Uranium Neutron Coincidence Collar (UNCL), that use moderated He-3 proportional counters along with necessarily low-intensity 241Am(Li) neutron sources. Scintillation-based fast-neutron detectors are a potentially superior technology to themore » existing AWCC and UNCL designs due to their spectroscopic capability and their inherently short neutron coincidence times that largely eliminate random coincidences and enable interrogation by stronger sources. One of the past impediments to the investigation and adoption of scintillation counters for the purpose of quantifying bulk uranium was the commercial availability of scintillators having the necessary neutron-gamma pulse-shape discrimination properties only as flammable liquids. Recently, Eljen EJ-299-34 PSD-plastic scintillator became commercially available. The present work is the first assessment of an array of PSD-plastic detectors for the purposes of quantifying bulk uranium. The detector panel used in the present work was originally built as the focal plane for a fast-neutron imager, but it was repurposed for the present investigation by construction of a stand to support the inner well of an AWCC immediately in front of the detector panel. The detector panel and data acquisition of this system are particularly well suited for performing active-well fast-neutron counting of LEU and HEU samples because the active detector volume is solid, the 241Am(Li) interrogating neutrons are largely below the detector threshold, and the segmented construction of the detector modules allow for separation of true neutron-neutron coincidences from inter-detector scattering using the kinematics of neutron scattering. The results from a series of measurements of a suite of uranium standards are presented, and compared to measurements of the same standards and source configurations using the AWCC. Using these results, the performance of the segmented detectors reconfigured as a well counter is predicted and outperforms the AWCC.« less

The HERSCHEL detector: high-rapidity shower counters for LHCb

NASA Astrophysics Data System (ADS)

Carvalho Akiba, K.; Alessio, F.; Bondar, N.; Byczynski, W.; Coco, V.; Collins, P.; Dumps, R.; Dzhelyadin, R.; Gandini, P.; Gruberg Cazon, B. R.; Jacobsson, R.; Johnson, D.; Manthey, J.; Mauricio, J.; McNulty, R.; Monteil, S.; Rachwal, B.; Ravonel Salzgeber, M.; Roy, L.; Schindler, H.; Stevenson, S.; Wilkinson, G.

2018-04-01

The HERSCHEL detector consists of a set of scintillating counters, designed to increase the coverage of the LHCb experiment in the high-rapidity regions on either side of the main spectrometer. The new detector improves the capabilities of LHCb for studies of diffractive interactions, most notably Central Exclusive Production. In this paper the construction, installation, commissioning, and performance of HERSCHEL are presented.

THE OUTER RADIATION BELT OF THE EARTH AT THE ALTITUDE OF 320 KM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vernov, S.N.; Savenko, I.A.; Shavrin, P.I.

1962-11-01

Scintillation and gas-discharge counters on the second Soviet spaceship allowed a detailed investigation of the outer radiation belt near the earth and established its boundaries in relation to longitude. The spaceship orbit was almost circular at an altitude of 306 to 339 km. The energy threshold of the counter channel was 25 kev. (W,D.M.)

The development of practice manual for LSC based on job analysis in radiation measurement and analysis

NASA Astrophysics Data System (ADS)

Shin, W. H.; Park, T. J.

2017-06-01

Radiation technology is closely related to the industrial growth and the creation of employment in Korea. The techniques as radiation or/and radioactivity measurement, and the practical skills achieving a higher level analysis are required. In this study, practice manual for liquid scintillation counter were developed by job analysis. Raw data applied in job analysis are collected by on/off line survey by 420 workers employed in KOREA. Importance-priority analysis was performed to make duties and competency unit that consists of knowledge, skills as each task. Refined data was reviewed by expert who experienced actual duties on site. Classification was conducted by focus group interview to deduct duties and competency unit. From the radiation devices in measurement and analysis, liquid scintillation counter was preferentially selected because of the high demands for training. Investigation of build-up status to liquid scintillation counter in KOREA was conducted. Then technical specification and operating procedure of 2 main devices were analyzed and integrated by practice manual. Duties and competency unit were applied to integrated materials respectively. To validate effectiveness, test curriculum was designed by the advanced course to workers who engaged in radiation measurement and analysis. The developed manual is structured to take advantage of test training. This manual will be a practical handbook that can improve the knowledge, skills of radiation workers in Korea.

Liquid argon scintillation light studies in LArIAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kryczynski, Pawel

2016-10-12

The LArIAT experiment is using its Liquid Argon Time Projection Chamber (LArTPC) in the second run of data-taking at the Fermilab Test Beam Facility. The goal of the experiment is to study the response of LArTPCs to charged particles of energies relevant for planned neutrino experiments. In addition, it will help to develop and evaluate the performance of the simulation, analysis, and reconstruction software used in other LAr neutrino experiments. Particles from a tertiary beam detected by LArIAT (mainly protons, pions and muons) are identified using a set of beamline detectors, including Wire Chambers, Time of Flight counters and Cherenkovmore » counters, as well as a simplified sampling detector used to detect muons. In its effort towards augmenting LArTPC technology for other neutrino experiments, LArIAT also takes advantage of the scintillating capabilities of LAr and is testing the possibility of using the light signal to help reconstruct calorimetric information and particle ID. In this report, we present results from these studies of the scintillation light signal to evaluate detector performance and calorimetry.« less

Abundances and energy spectra of high energy heavy cosmic-ray nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barthelmy, S.D.

1985-01-01

We have measured the relative abundances of the cosmic rays in the iron group region at energies from a few GeV/amu to approximately 70 GeV/amu. This is done using a balloon-borne instrument consisting of gas ionization chambers, a plastic scintillator, a plastic Cherenkov counter, and a CO/sub 2/ gas Cherenkov counter. The instrument was flown from Palestine, Texas in the fall of 1982 for a total exposure of 62 m/sup 2/-ster-hr at an average atmospheric depth of 4 g/cm/sup 2/. The elemental charge was determined for a combination of the scintillator and plastic Cherenkov detector. Results are reported on themore » /sub 22/Ti//sub 26/Fe, /sub 24/Cr//sub 26/Fe, /sub 20/Ca//sub 26/Fe, and /sub 28/Ni//sub 28/Fe abundance ratios from 2 to 70 GeV/amu. Within this work results on the previously unused method of relativistic rise in gas ionization chambers is detailed as well as results on the return to nonsaturation of plastic scintillators.« less

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.

Data Analysis for the Scintillating Optical Fiber Calorimeter (SOFCAL)

NASA Technical Reports Server (NTRS)

Christl, Mark J.

1997-01-01

The scintillating optical fiber calorimeter is a hybrid instrument with both active and passive components for measuring the proton and helium cosmic ray spectra from 0.2 to IO TeV kinetic energy. A thin emulsion/x-ray film chamber is situated between a cerenkov counter and an imaging calorimeter. Scintillating optical fibers sample the electromagnetic showers that develop in the calorimeter and identify the trajectory of cosmic rays that interact in SOFCAL. The emulsion/x-ray film data provide an in flight calibration for SOFCAL. The data reduction techniques used will be discussed and interim results of the analysis from a 20 hour balloon flight will be presented.

The spectrum of neutrons at 60 hg m(-2)

NASA Technical Reports Server (NTRS)

Barton, J. C.

1985-01-01

The rate of neutron interactions was measured for the energy range 7.5 to 60 MeV, using a 3.85 kg cell of liquid scintillator. The neutrons are selected by pulse shape discrimination, with anticoincidence counters used to reduce interference from muons transversing the scintillator. The observed flux is interpreted in terms of neutrons produced from environmental uranium and thorium, those resulting from the capture of negative muons in nuclei and those from fast muon interactions.

Gas Scintillation Proportional Counters for High-Energy X-ray Astronomy

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail; Ramsey, Brian; Apple, Jeffery

2003-01-01

A focal plane array of high-pressure gas scintillation proportional counters (GSPC) for a balloon-borne hard-x-ray telescope is under development at the Marshall Space Flight Center. These detectors have an active area of approx. 20 sq cm, and are filled with a high pressure (10(exp 6) Pa) xenon-helium mixture. Imaging is via crossed-grid position-sensitive phototubes sensitive in the UV region. The performance of the GSPC is well matched to that of the telescopes x-ray optics which have response to 75 keV and a focal spot size of approx. 500 microns. The detector s energy resolution, 4% FWHM at 60 keV, is adequate for resolving the broad spectral lines of astrophysical importance and for accurate continuum measurements. Full details of the instrument and its performance will be provided.

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

NASA Astrophysics Data System (ADS)

Richardson, Norman E., IV

Since the beginning of the nuclear age, there has been a strong demand for the development of efficient technologies for the detection of ionizing radiation. According to the United States' Department of Energy, the accurate assessment of fissile materials is essential in achieving the nonproliferation goals of enhancing safety and security of nuclear fuel cycle and nuclear energy facilities. Nuclear materials can be characterized by the measurement of prompt and delayed neutrons and gamma rays emitted in spontaneous or induced fission reactions and neutrons emitted in fission reactions are the distinctive signatures of nuclear materials. Today, the most widely used neutron detection technologies rely on thermal neutron capture reactions using a moderating material to cause the neutron to lose its energy prior to the detection event. This is necessary because as the fission event occurs, neutrons are emitted carrying high amounts of energy, typically on the order of mega electron volts (MeV). These energetic particles are classified as "fast" neutrons. For detecting the thermal neutrons, the Helium-3 (3He) gas-filled counters are arguably the most widely used technology of neutron detection. 3He counters have been the scientific standard for the nuclear engineering community for several decades, and have earned their place as a reliable technique for the detection of neutrons. However, 3He gas-filled counters have several disadvantages. First, gas-filled counters are not rigid and are sensitive to vibrations. Secondly, gas-filled counters are prone to the count rate limitations due to the physical processes of charge multiplication and transport in the gas medium in the electric field. Lastly, 3He gas-filled counters suffer from a supply shortage of the 3He isotope. As it is stated in [3], this shortage is created by the new demand for Helium-3 due to the deployment of neutron detectors at the borders after the 9/11 attack to help secure the nation against smuggled nuclear and radiological material. Moreover, the production of 3He isotope as a byproduct of security programs was drastically decreased. This isotope shortage coupled with the disadvantages of relying on a detector that requires neutron moderation before the detection of fission neutrons, poses a significant challenge in supporting the existing detection systems and the development of future technologies. To address this problem, a reliable and accurate alternative technology to detect neutrons emitted in fissions must be developed. One such alternative technology that shows promise in this application is the use of scintillators based on solid state materials (plastics) which are sensitive to fast neutrons. However, plastic scintillators are also sensitive to photons. Hence, it is necessary to separate the neutron signals from the photon signals, using the pulse shape discrimination (PSD) analysis. The PSD is based on the comparison of the pulse shapes of digitized signal waveforms. This approach allows for the measurement of fast neutrons without the necessity of their moderation. Because the fission spectrum neutrons are mainly fast, methods employing fast neutron detection are applicable for the assay of fissile materials. In addition, the average time of scintillation of the plastic medium is much shorter than those of the gaseous counters, thus allowing scintillation detectors to be used in high count rate environments. Furthermore, the temporal information of the fast neutron detection using multiple sensors enables the time correlation analysis of the fission neutron multiplicity. The study of time correlation measurements of fast neutrons using the array of plastic scintillators is the basis of this work. The array of four plastic scintillator detectors equipped with the digital data acquisition and analysis system was developed. The digital PSD analysis of detector signals "on-the-fly" was implemented for the array. The time coincidence measurement technique using the list mode was employed for two detectors operating on the single time scale. This was necessary as no fission source was available to be used as a fast neutron multiplicity source. The detection technology was tested using isotopic photon sources and a plutonium-beryllium neutron source. It was shown that the system can be effectively used for fast-neutron multiplicity measurements, through a "proof-of-concept" model, enabling a shorter width of the time coincidence window compared to the 3He counters. This result opens prospects to reduce the false coincidence rates in the neutron multiplicity measurements, thus increasing the sensitivity of nuclear material detection.

A history of radiation detection instrumentation.

PubMed

Frame, Paul W

2004-08-01

A review is presented of the history of radiation detection instrumentation. Specific radiation detection systems that are discussed include the human senses, photography, calorimetry, color dosimetry, ion chambers, electrometers, electroscopes, proportional counters, Geiger Mueller counters, scalers and rate meters, barium platinocyanide, scintillation counters, semiconductor detectors, radiophotoluminescent dosimeters, thermoluminescent dosimeters, optically stimulated luminescent dosimeters, direct ion storage, electrets, cloud chambers, bubble chambers, and bubble dosimeters. Given the broad scope of this review, the coverage is limited to a few key events in the development of a given detection system and some relevant operating principles. The occasional anecdote is included for interest.

A history of radiation detection instrumentation.

PubMed

Frame, Paul W

2005-06-01

A review is presented of the history of radiation detection instrumentation. Specific radiation detection systems that are discussed include the human senses, photography, calorimetry, color dosimetry, ion chambers, electrometers, electroscopes, proportional counters, Geiger Mueller counters, scalers and rate meters, barium platinocyanide, scintillation counters, semiconductor detectors, radiophotoluminescent dosimeters, thermoluminescent dosimeters, optically stimulated luminescent dosimeters, direct ion storage, electrets, cloud chambers, bubble chambers, and bubble dosimeters. Given the broad scope of this review, the coverage is limited to a few key events in the development of a given detection system and some relevant operating principles. The occasional anecdote is included for interest.

SCINTILLATOR COMPOSITION FOR COUNTERS AND METHOD OF MAKING

DOEpatents

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

1958-02-25

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

FAST NEUTRON SPECTROMETER

DOEpatents

Davis, F.J.; Hurst, G.S.; Reinhardt, P.W.

1959-08-18

An improved proton recoil spectrometer for determining the energy spectrum of a fast neutron beam is described. Instead of discriminating against and thereby"throwing away" the many recoil protons other than those traveling parallel to the neutron beam axis as do conventional spectrometers, this device utilizes protons scattered over a very wide solid angle. An ovoidal gas-filled recoil chamber is coated on the inside with a scintillator. The ovoidal shape of the sensitive portion of the wall defining the chamber conforms to the envelope of the range of the proton recoils from the radiator disposed within the chamber. A photomultiplier monitors the output of the scintillator, and a counter counts the pulses caused by protons of energy just sufficient to reach the scintillator.

Commissioning the SNO+ Detector

NASA Astrophysics Data System (ADS)

Caden, E.; Coulter, I.; SNO+ Collaboration

2017-09-01

SNO+ is a multipurpose liquid scintillator neutrino experiment based at SNOLAB in Sudbury, Ontario, Canada. The experiment’s main physics goal is a search for neutrinoless double beta decay in Tellurium-130, but SNO+ will also study low energy solar neutrinos, geo- and reactor-antineutrinos, among other topics. We are reusing much of the hardware from the original SNO experiment, but significant work has taken place to transform the heavy water detector into a liquid scintillator detector. We present upgrades and improvements to the read-out electronics and trigger system to handle the higher data rates expected by a scintillator experiment. We show the successful installation and testing of a hold-down rope net for the acrylic vessel to counter-act the buoyancy of organic liquid scintillator. We also describe the new scintillator process plant and cover gas systems that have been constructed to achieve the purification necessary to meet our physics goals. We are currently commissioning the experiment with ultra-pure water in preparation for filling with scintillator in early 2017 and present the current status of this work.

On-line remote monitoring of radioactive waste repositories

NASA Astrophysics Data System (ADS)

Calì, Claudio; Cosentino, Luigi; Litrico, Pietro; Pappalardo, Alfio; Scirè, Carlotta; Scirè, Sergio; Vecchio, Gianfranco; Finocchiaro, Paolo; Alfieri, Severino; Mariani, Annamaria

2014-12-01

A low-cost array of modular sensors for online monitoring of radioactive waste was developed at INFN-LNS. We implemented a new kind of gamma counter, based on Silicon PhotoMultipliers and scintillating fibers, that behaves like a cheap scintillating Geiger-Muller counter. It can be placed in shape of a fine grid around each single waste drum in a repository. Front-end electronics and an FPGA-based counting system were developed to handle the field data, also implementing data transmission, a graphical user interface and a data storage system. A test of four sensors in a real radwaste storage site was performed with promising results. Following the tests an agreement was signed between INFN and Sogin for the joint development and installation of a prototype DMNR (Detector Mesh for Nuclear Repository) system inside the Garigliano radwaste repository in Sessa Aurunca (CE, Italy). Such a development is currently under way, with the installation foreseen within 2014.

Systematic studies of small scintillators for new sampling calorimeter

NASA Astrophysics Data System (ADS)

Jacosalem, E. P.; Iba, S.; Nakajima, N.; Ono, H.; Sanchez, A. L. C.; Bacala, A. M.; Miyata, H.

2007-12-01

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

Multisector scintillation detector with fiber-optic light collection

NASA Astrophysics Data System (ADS)

Ampilogov, N. V.; Denisov, S. P.; Kokoulin, R. P.; Petrukhin, A. A.; Prokopenko, N. N.; Shulzhenko, I. A.; Unatlokov, I. B.; Yashin, I. I.

2017-07-01

A new type of scintillation detector for the use in high energy physics is described. The octagonal detector consists of eight triangular scintillator sectors with total area of 1 m2. Each sector represents two plates of 2 cm thick plastic scintillator. Seven 1 mm thick WLS fibers are laid evenly between the plates. The space between the fibers is filled with silicone compound to provide better light collection. Fiber ends from all eight sectors are gathered in the central part of the detector into a bunch and docked to the cathode of a FEU-115m photomultiplier. The read-out of the counter signals is carried out from 7th and 12th dynodes, providing a wide dynamic range up to about 10000 particles. The front-end electronics of the detector is based on the flash-ADC with a sampling frequency of 200 MHz. The features of detecting and recording systems of the multisector scintillation detector (MSD) and the results of its testing are discussed.

Field transportable beta spectrometer. Innovative technology summary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1998-12-01

The objective of the Large-Scale Demonstration Project (LSDP) is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) Chicago Pile-5 Test Reactor (CP-5). The purpose of the LSDP is to demonstrate that by using innovative and improved deactivation and decommissioning (D and D) technologies from various sources, significant benefits can be achieved when compared to baseline D and D technologies. One such capability being addressed by the D and D Focus Area is rapid characterization for facility contaminants. The technology was field demonstrated during the period January 7 through January 9, 1997, and offers several potentialmore » benefits, including faster turn-around time, cost reduction, and reduction in secondary waste. This report describes a PC controlled, field-transportable beta counter-spectrometer which uses solid scintillation coincident counting and low-noise photomultiplier tubes to count element-selective filters and other solid media. The dry scintillation counter used in combination with an element-selective technology eliminates the mess and disposal costs of liquid scintillation cocktails. Software in the instrument provides real-time spectral analysis. The instrument can detect and measure Tc-99, Sr-90, and other beta emitters reaching detection limits in the 20 pCi range (with shielding). Full analysis can be achieved in 30 minutes. The potential advantages of a field-portable beta counter-spectrometer include the savings gained from field generated results. The basis for decision-making is provided with a rapid turnaround analysis in the field. This technology would be competitive with the radiometric analysis done in fixed laboratories and the associated chain of custody operations.« less

A STUDY OF VARIOUS RADIATIONS DURING SPACE FLIGHTS OF SPUTNIKS, SPACE SHIPS AND ROCKETS (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vakulov, P.V.; Vernov, S.N.; Gorchakov, E.V.

1962-06-01

Data are presented on various radiation zones observed during the flights of the 3rd sputnik (launched May 15th, ship (Aug. 19 to 20, 1960, 339 km apogee and a 306 km perigee), the 3rd space ship (Dec. 1 to 2, 1960, 265 km apogee and a 187.3 km perigee), and the space rocket launched toward Venus on Feb. 12th, 1961. A radiation belt of electrons was detected at a height of 320 km above the earth's surface from the bremsstrahlung radiation determined on Geiger- Mueller and scintillation counters. Conjugate zones in the Northern hemisphere were linked with corresponding zones inmore » the Southern hemisphere. The position of the electron belt has remained relatively constant for about two years. The electron spectrum does not vary significantly. A count rate of >3.6 counts cm/ sup -2/ sec/sup -1/ was obtained in a Geiger-Mueller counter in the South Atlantic Ocean off the coast of Brazil. This high count rate was due to a magnetic anomaly in this region. An accurate distribution of cosmic ray intensity as a function of latitute was obtained from a comparison of the counts of the scintillation counter and the count of the STS-5 gas-discharge counter. Thirty references are included. (TTT)« less

Design of an ultrathin cold neutron detector

NASA Astrophysics Data System (ADS)

Osovizky, A.; Pritchard, K.; Yehuda-Zada, Y.; Ziegler, J.; Binkley, E.; Tsai, P.; Thompson, A.; Hadad, N.; Jackson, M.; Hurlbut, C.; Baltic, G. M.; Majkrzak, C. F.; Maliszewskyj, N. C.

2018-06-01

We describe the design and performance of an ultrathin (<2 mm) cold neutron detector consisting of 6LiF:ZnS(Ag) scintillator in which wavelength shifting fibers have been embedded to conduct scintillation photons out of the medium to a silicon photomultiplier photosensor. The counter has a neutron sensitive volume of 12 mm wide × 30 mm high × 1.4 mm deep. Twenty-four 0.5 mm diameter wavelength shifting fibers conduct the scintillation light out of the plane of the detector and are concentrated onto a 3 mm × 3 mm silicon photomultiplier. The detector is demonstrated to possess a neutron detection efficiency of 93% for 3.27 meV neutrons with a gamma ray rejection ratio on the order of 10-7.

On-line tritium production monitor

DOEpatents

Mihalczo, John T.

1993-01-01

A scintillation optical fiber system for the on-line monitoring of nuclear reactions in an event-by-event manner is described. In the measurement of tritium production one or more optical fibers are coated with enriched .sup.6 Li and connected to standard scintillation counter circuitry. A neutron generated .sup.6 Li(n )T reaction occurs in the coated surface of .sup.6 Li-coated fiber to produce energetic alpha and triton particles one of which enters the optical fiber and scintillates light through the fiber to the counting circuit. The coated optical fibers can be provided with position sensitivity by placing a mirror at the free end of the fibers or by using pulse counting circuits at both ends of the fibers.

On-line tritium production monitor

DOEpatents

Mihalczo, J.T.

1993-11-23

A scintillation optical fiber system for the on-line monitoring of nuclear reactions in an event-by-event manner is described. In the measurement of tritium production one or more optical fibers are coated with enriched {sup 6}Li and connected to standard scintillation counter circuitry. A neutron generated {sup 6}Li(n)T reaction occurs in the coated surface of {sup 6}Li-coated fiber to produce energetic alpha and triton particles one of which enters the optical fiber and scintillates light through the fiber to the counting circuit. The coated optical fibers can be provided with position sensitivity by placing a mirror at the free end of the fibers or by using pulse counting circuits at both ends of the fibers. 5 figures.

Comparison of the energy response of an ionization spectrometer for pions and protons

NASA Technical Reports Server (NTRS)

Jones, W. V.; Verma, S. D.

1971-01-01

An ionization spectrometer consisting of a sandwich of iron absorbers and plastic scintillation counters was used to measure the energy of pions and protons in the interval 10 to 1000 GeV. For the limited energy interval of 10 to 40 GeV, pions and protons were identified by an air cerenkov counter. Interactions in carbon were studied in a multiplate cloud chamber placed between the cerenkov counter and the spectrometer. Knowledge of these interactions were used in conjunction with a Monte Carlo simulation of the cascade process to study differences in the response of the spectrometer to pions and protons.

MEASUREMENT OF THE ABSORBED RADIATION DOSE ON THE THIRD SOVIET SATELLITE SPACESHIP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savenko, I.A.; Pisarenko, N.F.; Shavrin, P.I.

1963-05-01

The data obtained from two scintillation counters and one gas-discharge counter aboard the third Soviet satellite were reported. The main result is the conclusion that there is practically no danger in space flight at heights less than 350 km over a considerable period of time, in the absence of solar flares. A comparison of the data obtained on the second and third satellite permit practical inferences on radiation danger at greater heights as well. (C.E.S.)

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.

Development and Characterization of a High Sensitivity Segmented Fast Neutron Spectrometer (FaNS-2)

PubMed Central

Langford, T.J.; Beise, E.J.; Breuer, H.; Heimbach, C.R.; Ji, G.; Nico, J.S.

2016-01-01

We present the development of a segmented fast neutron spectrometer (FaNS-2) based upon plastic scintillator and 3He proportional counters. It was designed to measure both the flux and spectrum of fast neutrons in the energy range of few MeV to 1 GeV. FaNS-2 utilizes capture-gated spectroscopy to identify neutron events and reject backgrounds. Neutrons deposit energy in the plastic scintillator before capturing on a 3He nucleus in the proportional counters. Segmentation improves neutron energy reconstruction while the large volume of scintillator increases sensitivity to low neutron fluxes. A main goal of its design is to study comparatively low neutron fluxes, such as cosmogenic neutrons at the Earth's surface, in an underground environment, or from low-activity neutron sources. In this paper, we present details of its design and construction as well as its characterization with a calibrated 252Cf source and monoenergetic neutron fields of 2.5 MeV and 14 MeV. Detected monoenergetic neutron spectra are unfolded using a Singular Value Decomposition method, demonstrating a 5% energy resolution at 14 MeV. Finally, we discuss plans for measuring the surface and underground cosmogenic neutron spectra with FaNS-2. PMID:27226807

A new tritiated water measurement method with plastic scintillator pellets.

PubMed

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

2016-01-01

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

Measurement of wavelength-dependent refractive indices of liquid scintillation cocktails.

PubMed

Kossert, Karsten

2013-12-01

Refractive indices of several commercial liquid scintillation cocktails were measured by means of an automatic critical-angle dispersion refractometer in the wavelength range from 404.7 nm to 706.5 nm. The results are needed for various applications. In particular, detailed Monte Carlo simulations of liquid scintillation counters that include the computation of optical light require these data. In addition, the refractive index is an important parameter for studies of micelle sizes by means of dynamic light scattering. In this work, the refractive indices were determined for Ultima Gold™, Ultima Gold™ F, Ultima Gold™ LLT, Ultima Gold™ AB, Hionic Fluor™, Permafluor(®)E+, Mineral Oil Scintillator, Insta-Gel Plus, OptiPhase HiSafe 2, OptiPhase HiSafe 3, Ultima Gold™ XR, Insta-Gel Plus, AquaLight, MaxiLight and Ultima Gold™ MV at 16°C, 18°C, 20°C and 22°C. The carbon dioxide absorber Carbo-Sorb(®)E was also analyzed. For some scintillators, various batches were compared and mixtures with water or nitromethane were studied. © 2013 Published by Elsevier Ltd.

Primary Standardization of 152Eu by 4πβ(LS) – γ (Nal) coincidence counting and CIEMAT-NIST method

NASA Astrophysics Data System (ADS)

Ruzzarin, A.; da Cruz, P. A. L.; Ferreira Filho, A. L.; Iwahara, A.

2018-03-01

The 4πβ-γ coincidence counting and CIEMAT/NIST liquid scintillation method were used in the standardization of a solution of 152Eu. In CIEMAT/NIST method, measurements were performed in a Liquid Scintillation Counter model Wallac 1414. In the 4πβ-γ coincidence counting, the solution was standardized using a coincidence method with ‘‘beta-efficiency extrapolation”. A simple 4πβ-γ coincidence system was used, with acrylic scintillation cell coupled to two coincident photomultipliers at 180° each other and NaI(Tl) detector. The activity concentrations obtained were 156.934 ± 0.722 and 157.403 ± 0.113 kBq/g, respectively, for CIEMAT/NIST and 4πβ-γ coincidence counting measurement methods.

Investigation of Avalanche Photodiodes and Multipixel Photon Counters as Light Detectors for Cosmic Rays

NASA Astrophysics Data System (ADS)

Vasquez, Jaime; Saavedra, Arthur; Ramos, Roxana; Tavares, Pablo; Wade, Marcus; Fan, Sewan; Haag, Brooke

2013-04-01

Through the Research Scholars Institute, students of Hartnell Community College experimented with the application of avalanche photodiodes (APDs) as cosmic ray detectors during the summer of 2012. An APD detector was coupled with a 10 meter long wavelength shifting fiber (WSF) wrapped around a cylindrical plastic scintillator to maximize signal detection. A photomultiplier tube (PMT) was used in conjunction to detect the same scintillation light caused by incoming cosmic rays. Two APD detectors were evaluated to confirm the viability of the setup. In addition, a similar setup was recently utilized to implement multi-pixel photon counters (MPPCs) as readout detectors. Under this configuration, a high gain preamplifier was used to amplify the signals for both the MPPC and APD detectors. We report on our results characterizing the MPPC and discuss its overall performance. Compared to the APD, our findings suggest that the MPPC detector has greater sensitivity in detecting weak light signals, and can be used in place of the PMT for certain counting applications.

Performance of Gas Scintillation Proportional Counter Array for High-Energy X-Ray Observatory

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail; Ramsey, Brian; Apple, Jeffery

2004-01-01

A focal plane array of high-pressure gas scintillation proportional counters (GSPC) for a High Energy X-Ray Observatory (HERO) is developed at the Marshall Space Flight Center. The array is consisted from eight GSPCs and is a part of balloon born payload scheduled to flight in May 2004. These detectors have an active area of approximately 20 square centimeters, and are filled with a high pressure (10(exp 6) Pa) xenon-helium mixture. Imaging is via crossed-grid position-sensitive phototubes sensitive in the UV region. The performance of the GSPC is well matched to that of the telescopes x-ray optics which have response to 75 keV and a focal spot size of approximately 500 microns. The detector's energy resolution, 4% FWHM at 60 keV, is adequate for resolving the broad spectral lines of astrophysical importance and for accurate continuum measurements. Results of the on-earth detector calibration will be presented and in-flight detector performance will be provided, as available.

Study of Primary Cosmic Ray Electrons In Energy Range 10^11 - 10^13 Ev By Pamela Instrument.

NASA Astrophysics Data System (ADS)

Voronov, S.; Pamela Collaboration

The main goal of the magnetic spectrometer PAMELA is the study of antiparticle fluxes with energy up to 300 GeV in cosmic rays on board satellite. A modification of instrument was done by introducing of neutron detector. This device was placed under imaging calorimeter and bottom scintillator counter. It consists of two layers of 36 3He gas counters enveloped by a polyethylene moderator. The neutron detector gives additional possibility to identify the antiprotons going in aperture of spectrome- ter and generating the nuclear cascade in tungsten plates of calorimeter. This shower is followed by big number of neutrons in contrast to electromagnetic one caused by elec- tron or positron. From other side the combination of the imaging calorimeter, bottom scintillator and neutron detector constitute the independent instrument with large field of view which gives the possibility to measure the electron-positron cosmic ray com- ponent in energy range 1011-1013 eV with a rejection factor of order 10-4 regarding to nuclear one.

Cherenkov and Scintillation Properties of Cubic Zirconium

NASA Technical Reports Server (NTRS)

Christl, M.J.; Adams, J.H.; Parnell, T.A.; Kuznetsov, E.N.

2008-01-01

Cubic zirconium (CZ) is a high index of refraction (n =2.17) material that we have investigated for Cherenkov counter applications. Laboratory and proton accelerator tests of an 18cc sample of CZ show that the expected fast Cherenkov response is accompanied by a longer scintillation component that can be separated by pulse shaping. This presents the possibility of novel particle spectrometers which exploits both properties of CZ. Other high index materials being examined for Cherenkov applications will be discussed. Results from laboratory tests and an accelerator exposure will be presented and a potential application in solar energetic particle instruments will be discussed

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

NASA Astrophysics Data System (ADS)

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

1994-09-01

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

High energy cosmic ray iron spectrum experiment

NASA Technical Reports Server (NTRS)

Arens, J. F.; Balasubrahmanyan, V. K.; Ormes, J. F.; Schmidt, W. K. H.; Simon, M.; Spiegelhauer, H.

1978-01-01

An instrument containing a gas Cerenkov counter and an iron ionization spectrometer was constructed in order to measure the cosmic-ray iron spectrum to 300 GeV/nucleon. Trajectories of particles were determined by entopistic or position-determining scintillator systems. The geometric factors with and without the gas Cerenkov counter were 0.3 and 0.6 sq m-ster, respectively. The instrument was successfully flown in June 1976 without the spectrometer and in October 1976 with the spectrometer from Palestine, Texas. The June flight yielded 14.5 h of data; the October flight, 25 h.

Radiation measurement above the lunar surface by Kaguya gamma-ray spectrometer

NASA Astrophysics Data System (ADS)

Hasebe, Nobuyuki; Nagaoka, Hiroshi; Kusano, Hiroki; Hareyama, Matoko; Ideguchi, Yusuke; Shimizu, Sota; Shibamura, Eido

The lunar surface is filled with various ionizing radiations such as high energy galactic particles, albedo particles and secondary radiations of neutrons, gamma rays and other elementary particles. A high-resolution Kaguya Gamma-Ray Spectrometer (KGRS) was carried on the Japan’s lunar explorer SELENE (Kaguya), the largest lunar orbiter since the Apollo missions. The KGRS instrument employed, for the first time in lunar exploration, a high-purity Ge crystal to increase the identification capability of elemental gamma-ray lines. The Ge detector is surrounded by BGO and plastic counters as for anticoincidence shields. The KGRS measured gamma rays in the energy range from 200 keV to 13 MeV with high precision to determine the chemical composition of the lunar surface. It provided data on the abundance of major elements over the entire lunar surface. In addition to the gamma-ray observation by the KGRS, it successfully measured the global distribution of fast neutrons. In the energy spectra of gamma-rays observed by the KGRS, several saw-tooth- peaks of Ge are included, which are formed by the collision interaction of lunar fast neutrons with Ge atoms in the Ge crystal. With these saw-tooth-peaks analysis, global distribution of neutrons emitted from the lunara surface was successfully created, which was compared with the previous results obtained by Lunar Prospector neutron maps. Another anticoincidence counter, the plastic counter with 5 mm thickness, was used to veto radiation events mostly generated by charged particles. A single photomultiplier serves to count scintillation light from the plastic scintillation counter. The global map of counting rates observed by the plastic counter was also created, implying that the radiation counting rate implies the geological distribution, in spite that the plastic counter mostly measures high energy charged particles and energetic neutrons. These results are presented and discussed.

Countering Beam Divergence Effects with Focused Segmented Scintillators for High DQE Megavoltage Active Matrix Imagers

PubMed Central

Liu, Langechuan; Antonuk, Larry E; Zhao, Qihua; El-Mohri, Youcef; Jiang, Hao

2012-01-01

The imaging performance of active matrix flat-panel imagers designed for megavoltage imaging (MV AMFPIs) is severely constrained by relatively low x-ray detection efficiency, which leads to a detective quantum efficiency (DQE) of only ~1%. Previous theoretical and empirical studies by our group have demonstrated the potential for addressing this constraint through utilization of thick, two-dimensional, segmented scintillators with optically isolated crystals. However, this strategy is constrained by degradation of high-frequency DQE resulting from spatial resolution loss at locations away from the central beam axis due to oblique incidence of radiation. To address this challenge, segmented scintillators constructed so that the crystals are individually focused toward the radiation source are proposed and theoretically investigated. The study was performed using Monte Carlo simulations of radiation transport to examine the modulation transfer function and DQE of focused segmented scintillators with thicknesses ranging from 5 to 60 mm. The results demonstrate that, independent of scintillator thickness, the introduction of focusing largely restores spatial resolution and DQE performance otherwise lost in thick, unfocused segmented scintillators. For the case of a 60 mm thick BGO scintillator and at a location 20 cm off the central beam axis, use of focusing improves DQE by up to a factor of ~130 at non-zero spatial frequencies. The results also indicate relatively robust tolerance of such scintillators to positional displacements, of up to 10 cm in the source-to-detector direction and 2 cm in the lateral direction, from their optimal focusing position, which could potentially enhance practical clinical use of focused segmented scintillators in MV AMFPIs. PMID:22854009

Silicon photomultipliers for scintillating trackers

NASA Astrophysics Data System (ADS)

Rabaioli, S.; Berra, A.; Bolognini, D.; Bonvicini, V.; Bosisio, L.; Ciano, S.; Iugovaz, D.; Lietti, D.; Penzo, A.; Prest, M.; Rashevskaya, I.; Reia, S.; Stoppani, L.; Vallazza, E.

2012-12-01

In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain (∼106). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

Determination of Low Level Alpha and Beta Emitters Using Liquid-Liquid Extraction and a Liquid Scintillation Spectrometer

NASA Astrophysics Data System (ADS)

Yu, Yu-Fu; BjØRnstad, H. E.; Salbu, B.

Two radiochemical procedures for determination of low level strontium-90 and plutonium-239+240 in environmental and biological materials using combined selective solvent extraction with low level liquid scintillation counting have been presented. Y-90, the daughter nuclide of Sr-90, and Pu-239+240 are selectively extracted from nitric acid solution into 5% di(-2ethylhexyl)phosphoric acid (HDEHP) in toluene and the radionuclides of interest in organic phase are counted with an ultra low level scintillation counter "Quantulus". The lower detection limits for Sr-90 and Pu-239+240 are estimated to be 20 mBq and 0.3 mBq respectively. The developed procedures have been tested for soma environmental and biological samples and the preminarly results show that they are more simple and time-saving than traditional methods.

Catching Cosmic Rays with a DSLR

ERIC Educational Resources Information Center

Sibbernsen, Kendra

2010-01-01

Cosmic rays are high-energy particles from outer space that continually strike the Earth's atmosphere and produce cascades of secondary particles, which reach the surface of the Earth, mainly in the form of muons. These particles can be detected with scintillator detectors, Geiger counters, cloud chambers, and also can be recorded with commonly…

Detection of Neutrons with Scintillation Counters

DOE R&D Accomplishments Database

Hofstadter, R.

1948-11-01

Detection of slow neutrons by: detection of single gamma rays following capture by cadmium or mercury; detection of more than one gamma ray by observing coincidences after capture; detection of heavy charged particles after capture in lithium or baron nuclei; possible use of anthracene for counting fast neutrons investigated briefly.

Observation of EAS using a large water tank

NASA Technical Reports Server (NTRS)

Inoue, K.; Sakuyama, H.; Suzuki, N.; Suzuki, T.

1985-01-01

Using a large water tank (30 m in diameter, 4.5 m in depth) transition of extensive air showers (EAS) was investigated at Taro (200 m above sea level). There are set 150,0.4 sq m proportional counters on the bottom of the water tank. A conventional EAS array of 25 plastic scintillation detectors was arranged within several tens meter from the water tank. A proportional counter (10x10x200 cc x2) is made of a square shaped pipe of iron. Tungsten wire (100 mu m phi) is stretched tight in the center of the counter. A gas mixture of 90% argon and 10% methane is used at 760 mmHg. About 3000 EAS were obtained through 1 m of water since 1984.

A new 4π(LS)-γ coincidence counter at NCBJ RC POLATOM with TDCR detector in the beta channel.

PubMed

Ziemek, T; Jęczmieniowski, A; Cacko, D; Broda, R; Lech, E

2016-03-01

A new 4π(LS)-γ coincidence system (TDCRG) was built at the NCBJ RC POLATOM. The counter consists of a TDCR detector in the beta channel and scintillation detector with NaI(Tl) crystal in the gamma channel. The system is equipped with a digital board with FPGA, which records and analyses coincidences in the TDCR detector and coincidences between the beta and gamma channels. The characteristics of the system and a scheme of the FPGA implementation with behavioral simulation are given. The TDCRG counter was validated by activity measurements on (14)C and (60)Co solutions standardized in RC POLATOM using previously validated methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumazert, Jonathan; Coulon, Romain; Bertrand, Guillaume H. V.

2015-07-01

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

Performance studies towards a TOF-PET sensor using Compton scattering at plastic scintillators

NASA Astrophysics Data System (ADS)

Kuramoto, M.; Nakamori, T.; Gunji, S.; Kamada, K.; Shoji, Y.; Yoshikawa, A.; Aoki, T.

2018-01-01

We have developed a sensor head for a time-of-flight (TOF) PET scanner using plastic scintillators that have a very fast timing property. Given the very small cross section of photoelectric absorption in plastic scintillators at 511 keV, we use Compton scattering in order to compensate for detection efficiency. The detector will consist of two layers of scatterers and absorbers which are made of plastic and inorganic scintillators such as GAGG:Ce, respectively. Signals are read by monolithic Multi Pixel Photon Counters, and with energy deposits and interaction time stamps are being acquired. The scintillators are built to be capable of resolving interaction position in three dimensions, so that our system has also a function of depth-of-interaction (DOI) PET scanners. TOF resolution of ~ 200 ps (FWHM) is achieved in both cases of using the leading-edge discriminator and time-walk correction and using a configuration sensitive to DOI. Both the position resolution and spectroscopy are demonstrated using the prototype data acquisition system, with Compton scattering events subsequently being obtained. We also demonstrated that the background rejection technique using the Compton cone constraint could be valid with our system.

A rapid method for the simultaneous determination of gross alpha and beta activities in water samples using a low background liquid scintillation counter.

PubMed

Sanchez-Cabeza, J A; Pujol, L

1995-05-01

The radiological examination of water requires a rapid screening technique that permits the determination of the gross alpha and beta activities of each sample in order to decide if further radiological analyses are necessary. In this work, the use of a low background liquid scintillation system (Quantulus 1220) is proposed to simultaneously determine the gross activities in water samples. Liquid scintillation is compared to more conventional techniques used in most monitoring laboratories. In order to determine the best counting configuration of the system, pulse shape discrimination was optimized for 6 scintillant/vial combinations. It was concluded that the best counting configuration was obtained with the scintillation cocktail Optiphase Hisafe 3 in Zinsser low diffusion vials. The detection limits achieved were 0.012 Bq L-1 and 0.14 Bq L-1 for gross alpha and beta activity respectively, after a 1:10 concentration process by simple evaporation and for a counting time of only 360 min. The proposed technique is rapid, gives spectral information, and is adequate to determine gross activities according to the World Health Organization (WHO) guideline values.

Optimisation of nasal swab analysis by liquid scintillation counting.

PubMed

Dai, Xiongxin; Liblong, Aaron; Kramer-Tremblay, Sheila; Priest, Nicholas; Li, Chunsheng

2012-06-01

When responding to an emergency radiological incident, rapid methods are needed to provide the physicians and radiation protection personnel with an early estimation of possible internal dose resulting from the inhalation of radionuclides. This information is needed so that appropriate medical treatment and radiological protection control procedures can be implemented. Nasal swab analysis, which employs swabs swiped inside a nostril followed by liquid scintillation counting of alpha and beta activity on the swab, could provide valuable information to quickly identify contamination of the affected population. In this study, various parameters (such as alpha/beta discrimination, swab materials, counting time and volume of scintillation cocktail etc) were evaluated in order to optimise the effectiveness of the nasal swab analysis method. An improved nasal swab procedure was developed by replacing cotton swabs with polyurethane-tipped swabs. Liquid scintillation counting was performed using a Hidex 300SL counter with alpha/beta pulse shape discrimination capability. Results show that the new method is more reliable than existing methods using cotton swabs and effectively meets the analysis requirements for screening personnel in an emergency situation. This swab analysis procedure is also applicable to wipe tests of surface contamination to minimise the source self-absorption effect on liquid scintillation counting.

An easy method for Ra-226 determination in river waters by liquid-scintillation counting

NASA Astrophysics Data System (ADS)

Moreno, H. P.; Vioque, I.; Manjón, G.; García-Tenorio, R.

1999-01-01

226Ra activity concentration in river water was determined using a low background liquid scintillation counter. Radium was extracted from the samples as Ra-BaSO4 precipitate which, afterwards, was dissolved with EDTA in ammonia medium. Solution was transferred into a low potassium glass vial and then mixed with a scintillation cocktail. Two different scintillation cocktails were selected for comparison. Efficiency, recovery yield and α/β separation were studied with both liquid scintillation cocktails. One single measurement, made one month after radium separation, allows to calculate the226Ra concentration as well as to assess the presence of alpha contamination of the sample. In the case of negligible interferences,224Ra concentrations can be subsequently evaluated in the same sample by the measurement made just after chemical separation of radium. This method has been applied for the determination of226Ra and224Ra activity concentrations in river water collected from different locations along the Odiel river estuary area (South-west of Spain). The presence of chemical industry, the wastes of which are released into the river, could be connected with radium activity concentration enhancements in the water.

A new detector for mass spectrometry: direct detection of low energy ions using a multi-pixel photon counter.

PubMed

Wilman, Edward S; Gardiner, Sara H; Nomerotski, Andrei; Turchetta, Renato; Brouard, Mark; Vallance, Claire

2012-01-01

A new type of ion detector for mass spectrometry and general detection of low energy ions is presented. The detector consists of a scintillator optically coupled to a single-photon avalanche photodiode (SPAD) array. A prototype sensor has been constructed from a LYSO (Lu(1.8)Y(0.2)SiO(5)(Ce)) scintillator crystal coupled to a commercial SPAD array detector. As proof of concept, the detector is used to record the time-of-flight mass spectra of butanone and carbon disulphide, and the dependence of detection sensitivity on the ion kinetic energy is characterised.

An Environmental Chemistry Experiment: The Determination of Radon Levels in Water.

ERIC Educational Resources Information Center

Welch, Lawrence E.; Mossman, Daniel M.

1994-01-01

Describes a radiation experiment developed to complement a new environmental chemistry laboratory curriculum. A scintillation counter is used to measure radon in water. The procedure relies on the fact that toluene will preferentially extract radon from water. Sample preparation is complete in less than 90 minutes. Because the level of…

Quantitation of Lipase Activity from a Bee: An Introductory Enzyme Experiment.

ERIC Educational Resources Information Center

Farley, Kathleen A.; Jones, Marjorie A.

1989-01-01

This four-hour experiment uses a bee as a source of the enzyme which is reacted with a radioactive substrate to determine the specific activity of the enzyme. Uses thin layer chromatography, visible spectrophotometry, and liquid scintillation spectrometry (if not available a Geiger-Muller counter can be substituted). (MVL)

Study of muons near shower cores at sea level using the E594 neutrino detector

NASA Technical Reports Server (NTRS)

Goodman, J. A.; Gupta, S. C.; Freudenreich, H.; Sivaprasad, K.; Tonwar, S. C.; Yodh, G. B.; Ellsworth, R. W.; Goodman, M. C.; Bogert, D.; Burnstein, R.

1985-01-01

The E594 neutrino detector has been used to study the lateral distribution of muons of energy 3 GeV near shower cores. The detector consists of a 340 ton fine grain calorimeter with 400,000 cells of flash chamber and dimensions of 3.7 m x 20 m x 3.7 m (height). The average density in the calorimeter is 1.4 gm/sq cm, and the average Z is 21. The detector was triggered by four 0.6 sq m scintillators placed immediately on the top of the calorimeter. The trigger required at least two of these four counters. The accompanying extensive air showers (EAS) was sampled by 14 scintillation counters located up to 15 m from the calorimeter. Several off line cuts have been applied to the data. Demanding five particles in at least two of the trigger detectors, a total of 20 particles in all of them together, and an arrival angle for the shower 450 deg reduced the data sample to 11053 events. Of these in 4869 cases, a computer algorithm found at least three muons in the calorimeter.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aab, A.; Abreu, P.; Aglietta, M.

Here, AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is composed of three scintillation modules, with a 10 m 2 detection area per module. In this paper, a new generation of detectors, replacing the current multi-pixel photomultiplier tube (PMT) with silicon photo sensors (aka. SiPMs), ismore » proposed. The selection of the new device and its front-end electronics is explained. A method to calibrate the counting system that ensures the performance of the detector is detailed. This method has the advantage of being able to be carried out in a remote place such as the one where the detectors are deployed. High efficiency results, i.e. 98% efficiency for the highest tested overvoltage, combined with a low probability of accidental counting (~2%), show a promising performance for this new system.« less

Mass test of AdvanSiD model ASD-NUV3S-P SiliconPMs for the Pixel Timing Counter of the MEG II experiment

NASA Astrophysics Data System (ADS)

Rossella, M.; Bariani, S.; Barnaba, O.; Cattaneo, P. W.; Cervi, T.; Menegolli, A.; Nardò, R.; Prata, M. C.; Romano, E.; Scagliotti, C.; Simonetta, M.; Vercellati, F.

2017-02-01

The MEG II Timing Counter will measure the positron time of arrival with a resolution of 30 ps relying on two arrays of scintillator pixels read out by 6144 Silicon Photomultipliers (SiPMs) from AdvanSiD. They must be characterized, measuring their breakdown voltage, to assure that the gains of the SiPMs of each pixel are as uniform as possible, to maximize the pixel resolution. To do this an automatic test system that can measure sequentially the parameters of 32 devices has been developed.

Glass-fiber-based neutron detectors for high- and low-flux environments

NASA Astrophysics Data System (ADS)

Bliss, Mary; Brodzinski, Ronald L.; Craig, Richard A.; Geelhood, Bruce D.; Knopf, Michael A.; Miley, Harry S.; Perkins, Richard W.; Reeder, Paul L.; Sunberg, Debra S.; Warner, Ray A.; Wogman, Ned A.

1995-09-01

Pacific Northwest Laboratory (PNL) has fabricated cerium-activated lithium silicate scintillating fibers via a hot-downdraw process. These fibers typically have a operational transmission length (e(superscript -1) length) of greater than 2 meters. This permits the fabrication of devices which were not possible to consider. Scintillating fibers permit conformable devices, large-area devices, and extremely small devices; in addition, as the thermal-neutron sensitive elements in a fast neutron detection system, scintillating fibers can be dispersed within moderator, improving neutron economy, over that possible with commercially available (superscript 3)He or BF(subscript 3) proportional counters. These fibers can be used for national-security applications, in medical applications, in the nuclear-power industry, and for personnel protection at experimental facilities. Data are presented for devices based on single fibers and devices made up of ribbons containing many fibers under high-and low-flux conditions.

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.

RXTE observations of AGN

NASA Technical Reports Server (NTRS)

Rothschild, R. E.; Heindl, W. A.; Blanco, P. R.; Gruber, D. E.; Marsden, D. C.; Pelling, M. R.; Jahoda, K.; Madejski, G.; Swank, J. H.; Zdziarski, A. A.;

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deyglun, C.; Simony, B.; Perot, B.

The quantification of radioactive material is essential in the fields of safeguards, criticality control of nuclear processes, dismantling of nuclear facilities and components, or radioactive waste characterization. The Nuclear Measurement Laboratory (LMN) of CEA is involved in the development of time-correlated neutron detection techniques using plastic scintillators. Usually, 3He proportional counters are used for passive neutron coincidence counting owing to their high thermal neutron capture efficiency and gamma insensitivity. However, the global {sup 3}He shortage in the past few years has made these detectors extremely expensive. In addition, contrary to {sup 3}He counters for which a few tens of microsecondsmore » are needed to thermalize fast neutrons, in view to maximize the {sup 3}He(n,p){sup 3}H capture cross section, plastic scintillators are based on elastic scattering and therefore the light signal is formed within a few nanoseconds, correlated pulses being detected within a few dozen- or hundred nanoseconds. This time span reflects fission particles time of flight, which allows reducing accordingly the duration of the coincidence gate and thus the rate of random coincidences, which may totally blind fission coincidences when using {sup 3}He counters in case of a high (α,n) reaction rate. However, plastic scintillators are very sensitive to gamma rays, requiring the use of a thick metallic shield to reduce the corresponding background. Cross talk between detectors is also a major issue, which consists on the detection of one particle by several detectors due to elastic or inelastic scattering, leading to true but undesired coincidences. Data analysis algorithms are tested to minimize cross-talk in simultaneously activated detectors. The distinction between useful fission coincidences and the correlated background due to cross-talk, (α,n) and induced (n,2n) or (n,n'γ) reactions, is achieved by measuring 3-fold coincidences. The performances of a passive neutron coincidence counting system for radioactive waste drums using plastic scintillators have been studied using the Monte Carlo radiation transport code MCNPX-PoliMi v2.0 coupled to data processing algorithms developed with ROOT data analysis software. In addition to the correlated background, accidental coincidences are taken into account in the simulation by randomly merging pulses from different calculations with fission and (α,n) sources. (authors)« less

RADIATION-MEASURING SYSTEMS OF SOVIET ROCKETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vakulov, P.V.; Goryunov, N.N.; Logachev, Yu.I.

1961-11-01

The second and third Sputniks and all Soviet space rockets and spaceship- satellites were equipped with radiationmeasuring systems comprising scintillation and gasdischarge counters and shaping, amplification, and scaling circuits. The scintillation counters use photomultipliers having either 40 x 40 Nal(Tl) or 20 x 20 Csl(Tl) cylindrical crystals. Both types have a gain of ~5.10/sup 4/. The highvoltage battery supplies voltages to the photomultipliers without the use of voltage dividers. Pulses from the 11th, 9th, and 8th dynodes are used for counting the number of particles which produce energy yields from the crystal exceeding ~50 and 500 kev and 5 Mev,more » respectively. Fourstage transistor amplifiers with an over-all gain of ~100 are used for amplification of the counting pulses. The trigger-discriminator, together with the amplifier, is capable of counting (2.5 -- 3.0) x 10/sup 5/ pulses/sec and of insuring a threshold stability of 10% at ambient temperatures of --30 to +50 deg C and voltage variations of plus or minus 20%. Ionization is measured from the current of the 7th dynode and the photomultiplier collector, which permits readings as low as 10/sup -10/ amp to be made by the method of charge storage (in the capacitor) with subsequent discharge through a neon tube. A gas-disoharge counter with 50 mg/cm/sup 2/ stainless-steel walls, operating at 400 v, also measures ionization. Before coming to the scaling circuit, the 50 v negative pulses from this counter pass through a transistor amplifier which changes their polarity and reduces their duration to 8 to 10 mu sec. (OTS)« less

Gadolinium-loaded Plastic Scintillators for Thermal Neutron Detection using Compensation

NASA Astrophysics Data System (ADS)

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

2016-06-01

Plastic scintillator loading with gadolinium-rich organometallic complexes shows a high potential for the deployment of efficient and cost-effective neutron detectors. Due to the low-energy photon and electron signature of thermal neutron capture by Gd-155 and Gd-157, alternative treatment to pulse-shape discrimination has to be proposed in order to display a count rate. This paper discloses the principle of a compensation method applied to a two-scintillator system: a detection scintillator interacts with photon and fast neutron radiation and is loaded with gadolinium organometallic compound to become a thermal neutron absorber, while a not-gadolinium loaded compensation scintillator solely interacts with the fast neutron and photon part of incident radiation. After the nonlinear smoothing of the counting signals, a hypothesis test determines whether the resulting count rate post-background response compensation falls into statistical fluctuations or provides a robust indication of neutron activity. Laboratory samples are tested under both photon and neutron irradiations, allowing the authors to investigate the performance of the overall detection system in terms of sensitivity and detection limits, especially with regards to a similar-active volume He-3 based commercial counter. The study reveals satisfactory figures of merit in terms of sensitivity and directs future investigation toward promising paths.

Optimization of low-level LS counter Quantulus 1220 for tritium determination in water samples

NASA Astrophysics Data System (ADS)

Jakonić, Ivana; Todorović, Natasa; Nikolov, Jovana; Bronić, Ines Krajcar; Tenjović, Branislava; Vesković, Miroslav

2014-05-01

Liquid scintillation counting (LSC) is the most commonly used technique for measuring tritium. To optimize tritium analysis in waters by ultra-low background liquid scintillation spectrometer Quantulus 1220 the optimization of sample/scintillant ratio, choice of appropriate scintillation cocktail and comparison of their efficiency, background and minimal detectable activity (MDA), the effect of chemi- and photoluminescence and combination of scintillant/vial were performed. ASTM D4107-08 (2006) method had been successfully applied in our laboratory for two years. During our last preparation of samples a serious quench effect in count rates of samples that could be consequence of possible contamination by DMSO was noticed. The goal of this paper is to demonstrate development of new direct method in our laboratory proposed by Pujol and Sanchez-Cabeza (1999), which turned out to be faster and simpler than ASTM method while we are dealing with problem of neutralization of DMSO in apparatus. The minimum detectable activity achieved was 2.0 Bq l-1 for a total counting time of 300 min. In order to test the optimization of system for this method tritium level was determined in Danube river samples and also for several samples within intercomparison with Ruđer Bošković Institute (IRB).

Neutron detection by scintillation of noble-gas excimers

NASA Astrophysics Data System (ADS)

McComb, Jacob Collin

Neutron detection is a technique essential to homeland security, nuclear reactor instrumentation, neutron diffraction science, oil-well logging, particle physics and radiation safety. The current shortage of helium-3, the neutron absorber used in most gas-filled proportional counters, has created a strong incentive to develop alternate methods of neutron detection. Excimer-based neutron detection (END) provides an alternative with many attractive properties. Like proportional counters, END relies on the conversion of a neutron into energetic charged particles, through an exothermic capture reaction with a neutron absorbing nucleus (10B, 6Li, 3He). As charged particles from these reactions lose energy in a surrounding gas, they cause electron excitation and ionization. Whereas most gas-filled detectors collect ionized charge to form a signal, END depends on the formation of diatomic noble-gas excimers (Ar*2, Kr*2,Xe* 2) . Upon decaying, excimers emit far-ultraviolet (FUV) photons, which may be collected by a photomultiplier tube or other photon detector. This phenomenon provides a means of neutron detection with a number of advantages over traditional methods. This thesis investigates excimer scintillation yield from the heavy noble gases following the boron-neutron capture reaction in 10B thin-film targets. Additionally, the thesis examines noble-gas excimer lifetimes with relationship to gas type and gas pressure. Experimental data were collected both at the National Institute of Standards and Technology (NIST) Center for Neutron Research, and on a newly developed neutron beamline at the Maryland University Training Reactor. The components of the experiment were calibrated at NIST and the University of Maryland, using FUV synchrotron radiation, neutron imaging, and foil activation techniques, among others. Computer modeling was employed to simulate charged-particle transport and excimer photon emission within the experimental apparatus. The observed excimer scintillation yields from the 10B( n, alpha)7Li reaction are comparable to the yields of many liquid and solid neutron scintillators. Additionally, the observed slow triplet-state decay of neutron-capture-induced excimers may be used in a practical detector to discriminate neutron interactions from gamma-ray interactions. The results of these measurements and simulations will contribute to the development and optimization of a deployable neutron detector based on noble-gas excimer scintillation.

Imaging X-ray spectrophotometers

NASA Technical Reports Server (NTRS)

Hailey, C. J.; Hamilton, T. T.; Ku, W. H.-M.

1981-01-01

A new instrument which combines the good energy resolution of the gas scintillation proportional counter with the high position resolution of the microchannel plate is proposed. A study of the factors which determine the combined energy and position resolution of the new instrument is discussed. Submillimeter position resolution along with good energy resolution (8% fwhm at 6 keV) should be achievable.

High energy hadrons in air shower cores at mountain altitude

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Staa, R.; Aschenbach, B.; Boehm, E.

1974-01-01

At the Pic du Midi (730 g cm/sup -2/) in France an air shower array has been operated to study high-energy hadrons in air shower cores. The array consists of 13 scintillation counters of 0.25 mi each and a 14 mi high energy hadron detector. 2050 showers please delete the above abstract no 21733====

Activity measurements of 55Fe by two different methods

NASA Astrophysics Data System (ADS)

da Cruz, Paulo A. L.; Iwahara, Akira; da Silva, Carlos J.; Poledna, Roberto; Loureiro, Jamir S.; da Silva, Monica A. L.; Ruzzarin, Anelise

2018-03-01

A calibrated germanium detector and CIEMAT/NIST liquid scintillation method were used in the standardization of solution of 55Fe coming from a key-comparison BIPM. Commercial cocktails were used in source preparation for activity measurements in CIEMAT/NIST method. Measurements were performed in Liquid Scintillation Counter. In the germanium counting method standard point sources were prepared for obtaining atomic number versus efficiency curve of the detector in order to obtain the efficiency of 5.9 keV KX-ray of 55Fe by interpolation. The activity concentrations obtained were 508.17 ± 3.56 and 509.95 ± 16.20 kBq/g for CIEMAT/NIST and germanium methods, respectively.

Alkali Halide Microstructured Optical Fiber for X-Ray Detection

NASA Technical Reports Server (NTRS)

DeHaven, S. L.; Wincheski, R. A.; Albin, S.

2014-01-01

Microstructured optical fibers containing alkali halide scintillation materials of CsI(Na), CsI(Tl), and NaI(Tl) are presented. The scintillation materials are grown inside the microstructured fibers using a modified Bridgman-Stockbarger technique. The x-ray photon counts of these fibers, with and without an aluminum film coating are compared to the output of a collimated CdTe solid state detector over an energy range from 10 to 40 keV. The photon count results show significant variations in the fiber output based on the materials. The alkali halide fiber output can exceed that of the CdTe detector, dependent upon photon counter efficiency and fiber configuration. The results and associated materials difference are discussed.

Muon counting using silicon photomultipliers in the AMIGA detector of the Pierre Auger observatory

NASA Astrophysics Data System (ADS)

Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Anastasi, G. A.; Anchordoqui, L.; Andrada, B.; Andringa, S.; Aramo, C.; Arqueros, F.; Arsene, N.; Asorey, H.; Assis, P.; Aublin, J.; Avila, G.; Badescu, A. M.; Balaceanu, A.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Biteau, J.; Blaess, S. G.; Blanco, A.; Blazek, J.; Bleve, C.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Borodai, N.; Botti, A. M.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Briechle, F. L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Cancio, A.; Canfora, F.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Clay, R. W.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Cronin, J.; Dallier, R.; D'Amico, S.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; Debatin, J.; del Peral, L.; Deligny, O.; Di Giulio, C.; Di Matteo, A.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; D'Olivo, J. C.; Dorofeev, A.; dos Anjos, R. C.; Dova, M. T.; Dundovic, A.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fratu, O.; Freire, M. M.; Fujii, T.; Fuster, A.; García, B.; Garcia-Pinto, D.; Gaté, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Glass, H.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.; González, N.; Gookin, B.; Gordon, J.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Hasankiadeh, Q.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huege, T.; Hulsman, J.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Johnsen, J. A.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Kukec Mezek, G.; Kunka, N.; Kuotb Awad, A.; LaHurd, D.; Latronico, L.; Lauscher, M.; Lebrun, P.; Legumina, R.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopes, L.; López, R.; López Casado, A.; Luce, Q.; Lucero, A.; Malacari, M.; Mallamaci, M.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martínez Bravo, O.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melo, D.; Menshikov, A.; Messina, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Mockler, D.; Molina-Bueno, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafá, M.; Müller, G.; Muller, M. A.; Müller, S.; Naranjo, I.; Navas, S.; Nellen, L.; Neuser, J.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, H.; Núñez, L. A.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pedreira, F.; Pȩkala, J.; Pelayo, R.; Peña-Rodriguez, J.; Pereira, L. A. S.; Perrone, L.; Peters, C.; Petrera, S.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Ramos-Pollant, R.; Rautenberg, J.; Ravignani, D.; Reinert, D.; Revenu, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Rogozin, D.; Rosado, J.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sanabria Gomez, J. D.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Scarso, C.; Schauer, M.; Scherini, V.; Schieler, H.; Schmidt, D.; Scholten, O.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Sorokin, J.; Squartini, R.; Stanca, D.; Stanič, S.; Stasielak, J.; Strafella, F.; Suarez, F.; Suarez Durán, M.; Sudholz, T.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Taborda, O. A.; Tapia, A.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Torri, M.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valbuena-Delgado, A.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Villaseñor, L.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yang, L.; Yelos, D.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zong, Z.; Zuccarello, F.

2017-03-01

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is composed of three scintillation modules, with a 10 m2 detection area per module. In this paper, a new generation of detectors, replacing the current multi-pixel photomultiplier tube (PMT) with silicon photo sensors (aka. SiPMs), is proposed. The selection of the new device and its front-end electronics is explained. A method to calibrate the counting system that ensures the performance of the detector is detailed. This method has the advantage of being able to be carried out in a remote place such as the one where the detectors are deployed. High efficiency results, i.e. 98% efficiency for the highest tested overvoltage, combined with a low probability of accidental counting (~2%), show a promising performance for this new system.

Muon counting using silicon photomultipliers in the AMIGA detector of the Pierre Auger observatory

DOE PAGES

Aab, A.; Abreu, P.; Aglietta, M.; ...

2017-03-03

Here, AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is composed of three scintillation modules, with a 10 m 2 detection area per module. In this paper, a new generation of detectors, replacing the current multi-pixel photomultiplier tube (PMT) with silicon photo sensors (aka. SiPMs), ismore » proposed. The selection of the new device and its front-end electronics is explained. A method to calibrate the counting system that ensures the performance of the detector is detailed. This method has the advantage of being able to be carried out in a remote place such as the one where the detectors are deployed. High efficiency results, i.e. 98% efficiency for the highest tested overvoltage, combined with a low probability of accidental counting (~2%), show a promising performance for this new system.« less

DIII-D Neutron Measurement: Status and Plan for Simplification and Upgrade

NASA Astrophysics Data System (ADS)

Zhu, Y. B.; Heidbrink, W. W.; Taylor, P. L.; Finkenthal, D.

2017-10-01

Neutron diagnostics play key essential roles on DIII-D. Historically an 18-channel 2.45MeV D-D neutron measurement system based on 3He and BF3 proportional counters was inherited from Doublet-III including associated electronics and CAMAC data acquisition. Three fission chambers and two neutron scintillators were added in the 1980s and middle 1990s respectively. For Tritium burn-up studies, two 14MeV D-T neutron measurement systems were installed in 2009 and 2010. Operation and maintenance experience have led to a plan to simplify and upgrade these aging systems to provide a more economical and reliable solution for future DIII-D experiments. On simplification, most conventional expensive NIM and CAMAC modules will be removed. Advanced technologies like ultra-fast data acquisition and software-based pulse identification have been successfully tested. Significant data reduction and efficiency improvement will be achieved by real-time digital pulse identification with a field-programmable gate array. The partly renewed system will consist of 4 neutron counters for absolute calibration and 4 relatively calibrated neutron scintillators covering a wide measurement range. Work supported by US DOE under DE-FC02-04ER54698.

Monte Carlo simulation of β γ coincidence system using plastic scintillators in 4π geometry

NASA Astrophysics Data System (ADS)

Dias, M. S.; Piuvezam-Filho, H.; Baccarelli, A. M.; Takeda, M. N.; Koskinas, M. F.

2007-09-01

A modified version of a Monte Carlo code called Esquema, developed at the Nuclear Metrology Laboratory in IPEN, São Paulo, Brazil, has been applied for simulating a 4 πβ(PS)-γ coincidence system designed for primary radionuclide standardisation. This system consists of a plastic scintillator in 4 π geometry, for alpha or electron detection, coupled to a NaI(Tl) counter for gamma-ray detection. The response curves for monoenergetic electrons and photons have been calculated previously by Penelope code and applied as input data to code Esquema. The latter code simulates all the disintegration processes, from the precursor nucleus to the ground state of the daughter radionuclide. As a result, the curve between the observed disintegration rate as a function of the beta efficiency parameter can be simulated. A least-squares fit between the experimental activity values and the Monte Carlo calculation provided the actual radioactive source activity, without need of conventional extrapolation procedures. Application of this methodology to 60Co and 133Ba radioactive sources is presented and showed results in good agreement with a conventional proportional counter 4 πβ(PC)-γ coincidence system.

The Use of Fast Neutron Detection for Materials Accountability

NASA Astrophysics Data System (ADS)

Nakae, L. F.; Chapline, G. F.; Glenn, A. M.; Kerr, P. L.; Kim, K. S.; Ouedraogo, S. A.; Prasad, M. K.; Sheets, S. A.; Snyderman, N. J.; Verbeke, J. M.; Wurtz, R. E.

2014-02-01

For many years at LLNL, we have been developing time-correlated neutron detection techniques and algorithms for applications such as Arms Control, Threat Detection and Nuclear Material Assay. Many of our techniques have been developed specifically for the relatively low efficiency (a few percent) inherent in man-portable systems. Historically, thermal neutron detectors (mainly 3He) were used, taking advantage of the high thermal neutron interaction cross-sections, but more recently we have been investigating the use of fast neutron detection with liquid scintillators, inorganic crystals, and in the near future, pulse-shape discriminating plastics that respond over 1000 times faster (nanoseconds versus tens of microseconds) than thermal neutron detectors. Fast neutron detection offers considerable advantages, since the inherent nanosecond production timescales of fission and neutron-induced fission are preserved and measured instead of being lost in the thermalization of thermal neutron detectors. We are now applying fast neutron technology to the safeguards regime in the form of high efficiency counters. Faster detector response times and sensitivity to neutron momentum show promise in measuring, differentiating, and assaying samples that have modest to very high count rates, as well as mixed neutron sources (e.g., Pu oxide or Mixed Cm and Pu). Here we report on measured results with our existing liquid scintillator array and promote the design of a nuclear material assay system that incorporates fast neutron detection, including the surprising result that fast liquid scintillator becomes competitive and even surpasses the precision of 3He counters measuring correlated pairs in modest (kg) samples of plutonium.

Measurement of Entrance Surface Dose on an Anthropomorphic Thorax Phantom Using a Miniature Fiber-Optic Dosimeter

PubMed Central

Yoo, Wook Jae; Shin, Sang Hun; Jeon, Dayeong; Hong, Seunghan; Sim, Hyeok In; Kim, Seon Geun; Jang, Kyoung Won; Cho, Seunghyun; Youn, Won Sik; Lee, Bongsoo

2014-01-01

A miniature fiber-optic dosimeter (FOD) system was fabricated using a plastic scintillating fiber, a plastic optical fiber, and a multi-pixel photon counter to measure real-time entrance surface dose (ESD) during radiation diagnosis. Under varying exposure parameters of a digital radiography (DR) system, we measured the scintillating light related to the ESD using the sensing probe of the FOD, which was placed at the center of the beam field on an anthropomorphic thorax phantom. Also, we obtained DR images using a flat panel detector of the DR system to evaluate the effects of the dosimeter on image artifacts during posteroanterior (PA) chest radiography. From the experimental results, the scintillation output signals of the FOD were similar to the ESDs including backscatter simultaneously obtained using a semiconductor dosimeter. We demonstrated that the proposed miniature FOD can be used to measure real-time ESDs with minimization of DR image artifacts in the X-ray energy range of diagnostic radiology. PMID:24694678

Measurement of entrance surface dose on an anthropomorphic thorax phantom using a miniature fiber-optic dosimeter.

PubMed

Yoo, Wook Jae; Shin, Sang Hun; Jeon, Dayeong; Hong, Seunghan; Sim, Hyeok In; Kim, Seon Geun; Jang, Kyoung Won; Cho, Seunghyun; Youn, Won Sik; Lee, Bongsoo

2014-04-01

A miniature fiber-optic dosimeter (FOD) system was fabricated using a plastic scintillating fiber, a plastic optical fiber, and a multi-pixel photon counter to measure real-time entrance surface dose (ESD) during radiation diagnosis. Under varying exposure parameters of a digital radiography (DR) system, we measured the scintillating light related to the ESD using the sensing probe of the FOD, which was placed at the center of the beam field on an anthropomorphic thorax phantom. Also, we obtained DR images using a flat panel detector of the DR system to evaluate the effects of the dosimeter on image artifacts during posteroanterior (PA) chest radiography. From the experimental results, the scintillation output signals of the FOD were similar to the ESDs including backscatter simultaneously obtained using a semiconductor dosimeter. We demonstrated that the proposed miniature FOD can be used to measure real-time ESDs with minimization of DR image artifacts in the X-ray energy range of diagnostic radiology.

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

PubMed

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

2014-02-01

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

Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon

DOE PAGES

Cao, H.

2015-05-26

We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy pulsed narrow band neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We also report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median applied electric fields from 0more » to 970 V/cm. For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V/cm. Furthermore, we report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from 83mKr internal conversion electrons is comparable to that from 207Bi conversion electrons, we obtained the numbers of excitons (N ex) and ion pairs (N i) and their ratio (N ex/N i) produced by nuclear recoils from 16.9 to 57.3 keV. Motivated by arguments suggesting direction sensitivity in LAr-TPC signals due to columnar recombination, a comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field is presented for the first time.« less

Alkali halide microstructured optical fiber for X-ray detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeHaven, S. L., E-mail: stanton.l.dehaven@nasa.gov, E-mail: russel.a.wincheski@nasa.gov; Wincheski, R. A., E-mail: stanton.l.dehaven@nasa.gov, E-mail: russel.a.wincheski@nasa.gov; Albin, S., E-mail: salbin@nsu.edu

Microstructured optical fibers containing alkali halide scintillation materials of CsI(Na), CsI(Tl), and NaI(Tl) are presented. The scintillation materials are grown inside the microstructured fibers using a modified Bridgman-Stockbarger technique. The x-ray photon counts of these fibers, with and without an aluminum film coating are compared to the output of a collimated CdTe solid state detector over an energy range from 10 to 40 keV. The photon count results show significant variations in the fiber output based on the materials. The alkali halide fiber output can exceed that of the CdTe detector, dependent upon photon counter efficiency and fiber configuration. Themore » results and associated materials difference are discussed.« less

Development of Labview based data acquisition and multichannel analyzer software for radioactive particle tracking system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, Nur Aira Abd, E-mail: nur-aira@nuclearmalaysia.gov.my; Yussup, Nolida; Ibrahim, Maslina Bt. Mohd

2015-04-29

A DAQ (data acquisition) software called RPTv2.0 has been developed for Radioactive Particle Tracking System in Malaysian Nuclear Agency. RPTv2.0 that features scanning control GUI, data acquisition from 12-channel counter via RS-232 interface, and multichannel analyzer (MCA). This software is fully developed on National Instruments Labview 8.6 platform. Ludlum Model 4612 Counter is used to count the signals from the scintillation detectors while a host computer is used to send control parameters, acquire and display data, and compute results. Each detector channel consists of independent high voltage control, threshold or sensitivity value and window settings. The counter is configured withmore » a host board and twelve slave boards. The host board collects the counts from each slave board and communicates with the computer via RS-232 data interface.« less

Design and construction of pulsed neutron diagnostic system for plasma focus device (SBUPF1).

PubMed

Moghadam, Sahar Rajabi; Davani, Fereydoon Abbasi

2010-07-01

In this paper, two designs of pulsed neutron counter structure are introduced. To increase the activation counter efficiency, BC-400 plastic scintillator plates along with silver foils are utilized. Rectangular cubic and cylindrical geometries for activation counter cell are modeled using MCNP4C code. Eventually, an optimum length of 14 cm is calculated for the detector cell and optimum numbers of 20 silver foils for rectangular cubic geometry and ten foils for cylindrical geometry have been acquired. Due to the high cost of cutting, polishing of plastics, and etc., the rectangular cubic design is found to be more economical than the other design. In order to examine the functionality and ensure the detector output and corresponding designing, neutron yield of a 2.48 kJ plasma focus device (SBUPF1) in 8 mbar pressure with removal source method for calibration was measured (3.71+/-0.32)x10(7) neutrons per shot.

A program to study antiprotons in the cosmic rays: Arizona collaboration

NASA Technical Reports Server (NTRS)

Bowen, Theodore

1987-01-01

The Low Energy AntiProton (LEAP) experiment was designed to measure the primary antiproton flux in the 200 MeV to 1 GeV kinetic energy range. A superconducting magnetic spectrometer, a time-of-flight (TOF) detector, and a Cherenkov counter are the main components of LEAP. An additional scintillation detector was designed and constructed to detect the passage of particles through the bottom of the Cherenkov counter. The LEAP package was launched on August 22, 1987, and enjoyed a 27 hour flight, with 23 hours of data at high altitude. Preliminary plans for data analysis include using the Micro-Vax at the University of Arizona for data reduction of the Cherenkov and S2 signals.

Radiation effects on ALICE V0 detector components

NASA Astrophysics Data System (ADS)

Cheynis, B.; Ducroux, L.; Grossiord, J.-Y.; Guichard, A.; Pillot, P.; Rapp, B.; Tieulent, R.; Tromeur, W.; Zoccarato, Y.

2006-12-01

The 60 MeV proton beam delivered by the RADEF facility of the University of Jyväskylä (Finland) was used to measure the radiation effects on the counter components of the V0 detector of ALICE. There are the scintillator BC404, the wavelength shifting fibres BCF9929A and the optical fibres BCF98 from Bicron (Saint-Gobain). The light yield and the time resolution given by a counter of the inner ring of the V0C array, mounted within a dedicated device, were measured as a function of the radiation dose up to about 300 krad. A global light attenuation of the order of 30% can be anticipated during 10 years of ALICE running.

A swimming pool array for ultra high energy showers

NASA Astrophysics Data System (ADS)

Yodh, Gaurang B.; Shoup, Anthony; Barwick, Steve; Goodman, Jordan A.

1992-11-01

A very preliminary design concept for an array using water Cherenkov counters, built out of commercially available backyard swimming pools, to sample the electromagnetic and muonic components of ultra high energy showers at large lateral distances is presented. The expected performance of the pools is estimated using the observed lateral distributions by scintillator and water Cherenkov arrays at energies above 1019 eV and simulations.

Support of research in X-ray astronomy

NASA Technical Reports Server (NTRS)

Garmire, G.

1983-01-01

Activities described include: (1) the evaluation of CCD detectors for X-ray astronomy applications; (2) contributions to the development of an imaging gas scintillation proportional counter; (3) the evaluation of certain metal oxide crystals as potential radiation detectors; (4) optical observations and searches for X-ray sources discovered by the HEAO-1 A2 experiment; and (5) theoretical modeling of nonequilibrium ionization structure of supernova remnants.

RADIATION HAZARD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savenko, I.A.; Pisarenko, N.F.; Shavrin, P.I.

1961-01-01

Analysis of data obtained by Sputnik V (August 19, 1961) at about 320 km made it possible to delineate the position of the radiation belts and to estimate the amount of radiation hazard present. Scintillation counter data show that the radiation in the belts is anisotropic and that the energy flux under a layer of matter of 2 x 10/sup -3/ g cm/sup -2/ is 10/sup 10/ ev cm/sup -2/ sec/sup -1/. The mean energy released per quantum in the scintillation counter crystal is computed at 2.0 x 10/sup 5/ ev and the intensity of electrons in the outer beltmore » at 5 x 10/sup 4/ particles cm/sup -2/ sec/sup -1/. The radiation dosage absorbed inside Sputnik V was determined by dividing the amount of energy liberated in the sodium iodide crystal of the scinitillation counter by the weight of the crystal (36.4 g) without the need of a detailed examination of the composition and spectrum of the radiation. A dosage value of 7 mrad/24 hr was obtained; in terms of the RBE (relative biological effect) of the cosmic charged particles this amounted to 5O mrem/24 hr. This dosage is considered relatively safe for astronauts during flights along trajectories similar to that of Sputnik V when the sun is quiet. Solar flares, however, could bring about an increase in radiation. Owing to latitude and longitude effects and the specifi distribution of radiation at this height, the dosage per orbit ranged from 0.35 to 0.70 mrad. (OTS)« less

Measurement of tritium with plastic scintillator surface improvement with plasma treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshihara, Y.; Furuta, E.; Ohyama, R.I.

2015-03-15

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giacomelli, L.; Department of Physics, Università degli Studi di Milano-Bicocca, Milano; Conroy, S.

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

Study of n- γ discrimination by zero-crossing method with SiPM based scintillation detectors

NASA Astrophysics Data System (ADS)

Grodzicka-Kobylka, M.; Szczesniak, T.; Moszyński, M.; Swiderski, L.; Wolski, D.; Baszak, J.; Korolczuk, S.; Schotanus, P.

2018-03-01

The paper presents a study of n / γ discrimination with 4x4 ch and 8x8 ch Multi Pixel Photon Counter (MPPC) arrays in neutron detectors based on Stilbene and EJ299-33 plastic scintillators. The n / γ discrimination showed an excellent capability of the MPPC arrays, comparable to that observed earlier with the classical PMTs. Particularly, an application of a zero-crossing method of n - γ discrimination prevented deterioration of the discrimination by the slow response of the Silicon Photomultiplier (SiPM, or MPPC interchangeably) array related to its large capacitance. It was confirmed by a good agreement of the Figure of Merit normalized to the number of photoelectrons determined for the MPPC arrays and XP5500 PMT.

Effect of quench on alpha/beta pulse shape discrimination of liquid scintillation cocktails.

PubMed

DeVol, Timothy A; Theisen, Christopher D; DiPrete, David P

2007-05-01

The objectives of this paper are (1) to illustrate that knowledge of the external quench parameter is insufficient to properly setup a pulse shape discriminating liquid scintillation counter (LSC) for quantitative measurement, (2) to illustrate dependence on pulse shape discrimination on the radionuclide (more than just radiation and energy), and (3) to compare the pulse shape discrimination (PSD) of two commercial instruments. The effects various quenching agents, liquid scintillation cocktails, radionuclides, and LSCs have on alpha/beta pulse shape discriminating liquid scintillation counting were quantified. Alpha emitting radionuclides (239)Pu and (241)Am and beta emitter (90)Sr/(90)Y were investigated to quantify the nuclide dependence on alpha/beta pulse shape discrimination. Also, chemical and color quenching agents, nitromethane, nitric acid, and yellow dye impact on alpha/beta pulse shape discrimination using PerkinElmer Optiphase "HiSafe" 2 and 3, and Ultima Gold AB liquid scintillation cocktails were determined. The prepared samples were counted on the PerkinElmer Wallac WinSpectral 1414 alpha/beta pulse shape discriminating LSC. It was found that for the same level of quench, as measured by the external quench parameter, different quench agents influenced the pulse shape discrimination and the pulse shape discrimination parameters differently. The radionuclide also affects alpha/beta pulse shape discrimination. By comparison with the PerkinElmer Tri-carb 3150 TR/AB, the Wallac 1414 exhibited better pulse shape discrimination capability under the same experimental conditions.

The “Carpet-3” air shower array to search for diffuse gamma rays with energy Eγ>100TeV

NASA Astrophysics Data System (ADS)

Dzhappuev, D. D.; I, V. B. Petkov V.; Kudzhaev, A. U.; Lidvansky, A. S.; Volchenko, V. I.; Volchenko, G. V.; Gorbacheva, E. A.; Dzaparova, I. M.; Klimenko, N. F.; Kurenya, A. N.; Mikhilova, O. I.; Khadzhiev, M. M.; Yanin, A. F.

2017-12-01

At present an experiment for measuring the flux of cosmic diffuse gamma rays with energy higher than 100 TeV (experiment “Carpet-3”) is being prepared at the Baksan Neutrino Observatory of the Institute for Nuclear Research, Russian Academy of Sciences. The preparation of the experiment implies considerable enlargement of the area of both muon detector and surface part of the shower array. At the moment the plastic scintillation counters with a total continuous area of 410 m2 are installed in the muon detector (MD) underground tunnels, and they are totally equipped with electronics. Adjusting of the counters and their electronic circuits is in progress. Six modules of shower detectors (out of twenty planned to be installed) have already been placed on the surface of the MD absorber. A new liquid scintillation detector is developed for modules of the ground -surface part of the array, whose characteristics are presented. It is shown that the “Carpet-3” air shower array will have the best sensitivity to the flux of primary gamma rays with energies in the range 100TeV - 1PeV, being quite competitive in gamma-ray astronomy at such energies.

A Measurement of the proton-proton inelastic scattering cross-section at center off mass energy = 7 TeV with the ATLAS detector at the LHC

NASA Astrophysics Data System (ADS)

Tompkins, Lauren Alexandra

The first measurement of the inelastic cross-section for proton-proton collisions at a center of mass energy of 7 TeV using the ATLAS detector at the Large Hadron Collider is presented. From a dataset corresponding to an integrated luminosity of 20 inverse microbarns, events are selected by requiring activity in scintillation counters mounted in the forward region of the ATLAS detector. An inelastic cross-section of 60.1 +/- 2.1 millibarns is measured for the subset of events visible to the scintillation counters. The uncertainty includes the statistical and systematic uncertainty on the measurement. The visible events satisfy xi > 5 x 10 -6, where xi=MX 2/s is calculated from the invariant mass, MX, of hadrons selected using the largest rapidity gap in the event. For diffractive events this corresponds to requiring at least one of the dissociation masses to be larger than 15.7~GeV. Using an extrapolation dependent on the model for the differential diffractive mass distribution, an inelastic cross-section of 69.1 +/- 2.4 (exp) +/- 6.9 (extr) millibarns is determined, where (exp) indicates the experimental uncertainties and (extr) indicates the uncertainty due to the extrapolation from the limited xi-range to the full inelastic cross-section.

A methodology to evaluate occupational internal exposure to fluorine-18.

PubMed

Oliveira, C M; Dantas, A L A; Dantas, B M

2009-11-15

The objective of this work is to develop procedures for internal monitoring of (18)F to be applied in cases of possible incorporation of fluoride and (18)FDG, using in vivo and in vitro methods of measurements. The Na I (Tl) 8" x 4" scintillation detector installed at IRD-Whole Body Counter was calibrated for measurements with a whole body anthropomorphic phantom, simulating homogeneous distribution of (18)F in the body. The NaI(Tl) 3"x 3" scintillation detector installed at the IRD-Whole Body Counter was calibrated for in vivo measurements with a brain phantom inserted in an artificial skull, simulating (18)FDG incorporation. The HPGe detection system installed at the IRD-Bioassay Laboratory was calibrated for in vitro measurements of urine samples with 1 liter plastic bottles containing a standard liquid source. A methodology for bioassay data interpretation, based on standard ICRP models edited with the software AIDE-version 6, was established. It is concluded that in vivo measurements have sufficient sensitivity for monitoring (18)F in the forms of fluoride and (18)FDG. The use of both in vitro and in vivo bioassay data can provide useful information for the interpretation of bioassay data in cases of accidental incorporation in order to identify the chemical form of (18)F incorporated.

Prototype muon detectors for the AMIGA component of the Pierre Auger Observatory

DOE PAGES

Aab, Alexander

2016-02-17

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory to extend its range of detection and to directly measure the muon content of the particle showers. It consists of an infill of surface water-Cherenkov detectors accompanied by buried scintillator detectors used for muon counting. The main objectives of the AMIGA engineering array, referred to as the Unitary Cell, are to identify and resolve all engineering issues as well as to understand the muon-number counting uncertainties related to the design of the detector. The mechanical design, fabrication and deployment processes of the muonmore » counters of the Unitary Cell are described in this document. These muon counters modules comprise sealed PVC casings containing plastic scintillation bars, wavelength-shifter optical fibers, 64 pixel photomultiplier tubes, and acquisition electronics. The modules are buried approximately 2.25 m below ground level in order to minimize contamination from electromagnetic shower particles. The mechanical setup, which allows access to the electronics for maintenance, is also described in addition to tests of the modules' response and integrity. As a result, the completed Unitary Cell has measured a number of air showers of which a first analysis of a sample event is included here.« less

1985 Nuclear Science Symposium, 32nd, and 1985 Symposium on Nuclear Power Systems, 17th, San Francisco, CA, October 23-25, 1985, Proceedings

NASA Technical Reports Server (NTRS)

1986-01-01

The present conference ranges over topics in high energy physics instrumentation, detectors, nuclear medical applications, health physics and environmental monitoring, reactor instrumentation, nuclear spacecraft instrumentation, the 'Fastbus' data acquisition system, circuits and systems for nuclear research facilities, and the development status of nuclear power systems. Specific attention is given to CCD high precision detectors, a drift chamber preamplifier, a Cerenkov ring imaging detector, novel scintillation glasses and scintillating fibers, a modular multidrift vertex detector, radial wire drift chambers, liquid argon polarimeters, a multianode photomultiplier, the reliability of planar silicon detectors, the design and manufacture of wedge and strip anodes, ultrafast triode photodetectors, photomultiplier tubes, a barium fluoride plastic scintillator, a fine grained neutron hodoscope, the stability of low leakage silicon photodiodes for crystal calorimeters, and X-ray proportional counters. Also considered are positron emission tomography, single photon emission computed tomography, nuclear magnetic resonance imaging, Geiger-Muller detectors, nuclear plant safeguards, a 32-bit Fastbus computer, an advanced light water reactor, and nuclear plant maintenance.

The UCSD high energy X-ray timing experiment cosmic ray particle anticoincidence detector

NASA Technical Reports Server (NTRS)

Hink, P. L.; Rothschild, R. E.; Pelling, M. R.; Macdonald, D. R.; Gruber, D. E.

1991-01-01

The HEXTE, part of the X-Ray Timing Explorer (XTE), is designed to make high sensitivity temporal and spectral measurements of X-rays with energies between 15 and 250 keV using NaI/CsI phoswich scintillation counters. To achieve the required sensitivity it is necessary to provide anticoincidence of charged cosmic ray particles incident upon the instrument, some of which interact to produce background X-rays. The proposed cosmic ray particle anticoincidence shield detector for HEXTE uses a novel design based on plastic scintillators and wavelength-shifter bars. It consists of five segments, each with a 7 mm thick plastic scintillator, roughly 50 cm x 50 cm in size, coupled to two wavelength-shifter bars viewed by 1/2 inch photomultiplier tubes. These segments are configured into a five-sided, box-like structure around the main detector system. Results of laboratory testing of a model segment, and calculations of the expected performance of the flight segments and particle anticoincidence detector system are presented to demonstrate that the above anticoincidence detector system satisfies its scientific requirements.

Investigation of Very Fast Light Detectors: Silicon Photomultiplier and Micro PMT for a Cosmic Ray Array

NASA Astrophysics Data System (ADS)

Cervantes, Omar; Reyes, Liliana; Hooks, Tyler; Perez, Luis; Ritt, Stefan

2016-03-01

To construct a cosmic detector array using 4 scintillation detectors, we investigated 2 recent light sensor technologies from Hamamatsu, as possible readout detectors. First, we investigated several homemade versions of the multipixel photon counter (MPPC) light sensors. These detectors were either biased with internal or external high voltage power supplies. We made extensive measurements to confirm for the coincidence of the MPPC devices. Each sensor is coupled to a wavelength shifting fiber (WSF) that is embedded along a plastic scintillator sheet (30cmx60cmx1/4''). Using energetic cosmic rays, we evaluated several of these homemade detector modules placed above one another in a light proof enclosure. Next, we assembled 2 miniaturized micro photomultiplier (micro PMT), a device recently marketed by Hamamatsu. These sensors showed very fast response times. With 3 WSF embedded in scintillator sheets, we performed coincidence experiments. The detector waveforms were captured using the 5GS/sec domino ring sampler, the DRS4 and our workflow using the CERN PAW package and data analysis results would be presented. Title V Grant.

Development of a cylindrical tracking detector with multichannel scintillation fibers and pixelated photon detector readout

NASA Astrophysics Data System (ADS)

Akazawa, Y.; Miwa, K.; Honda, R.; Shiozaki, T.; Chiga, N.

2015-07-01

We are developing a cylindrical tracking detector for a Σp scattering experiment in J-PARC with scintillation fibers and the Pixelated Photon Detector (PPD) readout, which is called as cylindrical fiber tracker (CFT), in order to reconstruct trajectories of charged particles emitted inside CFT. CFT works not only as a tracking detector but also a particle identification detector from energy deposits. A prototype CFT consisting of two straight layers and one spiral layer was constructed. About 1100 scintillation fibers with a diameter of 0.75 mm (Kuraray SCSF-78 M) were used. Each fiber signal was read by Multi-Pixel Photon Counter (MPPC, HPK S10362-11-050P, 1×1 mm2, 400 pixels) fiber by fiber. MPPCs were handled with Extended Analogue Silicon Photomultipliers Integrated ReadOut Chip (EASIROC) boards, which were developed for the readout of a large number of MPPCs. The energy resolution of one layer was 28% for a 70 MeV proton where the energy deposit in fibers was 0.7 MeV.

Investigation of Self Triggered Cosmic Ray Detectors using Silicon Photomultiplier

NASA Astrophysics Data System (ADS)

Knox, Adrian; Niduaza, Rommel; Hernandez, Victor; Ruiz, Daniel; Ramos, Daniel; Fan, Sewan; Fatuzzo, Laura; Ritt, Stefan

2015-04-01

The silicon photomultiplier (SiPM) is a highly sensitive light detector capable of measuring single photons. It costs a fraction of the photomultiplier tube and operates slightly above the breakdown voltage. At this conference we describe our investigation of SiPM, the multipixel photon counters (MPPC) from Hamamatsu as readout detectors for plastic scintillators working for detecting cosmic ray particles. Our setup consists of scintillator sheets embedded with blue to green wavelength shifting fibers optically coupled to MPPCs to detect scintillating light. Four detector assemblies would be constructed and arranged to work in self triggered mode. Using custom matching tee boxes, the amplified MPPC signals are fed to discriminators with threshold set to give a reasonable coincidence count rate. Moreover, the detector waveforms are digitized using a 5 Giga Samples per second waveform digitizer, the DRS4, and triggered with the coincidence logic to capture the MPPC waveforms. Offline analysis of the digitized waveforms is accomplished using the CERN package PAW and results of our experiments and the data analysis would also be discussed. US Department of Education Title V Grant Number PO31S090007.

Improving Depth, Energy and Timing Estimation in PET Detectors with Deconvolution and Maximum Likelihood Pulse Shape Discrimination.

PubMed

Berg, Eric; Roncali, Emilie; Hutchcroft, Will; Qi, Jinyi; Cherry, Simon R

2016-11-01

In a scintillation detector, the light generated in the scintillator by a gamma interaction is converted to photoelectrons by a photodetector and produces a time-dependent waveform, the shape of which depends on the scintillator properties and the photodetector response. Several depth-of-interaction (DOI) encoding strategies have been developed that manipulate the scintillator's temporal response along the crystal length and therefore require pulse shape discrimination techniques to differentiate waveform shapes. In this work, we demonstrate how maximum likelihood (ML) estimation methods can be applied to pulse shape discrimination to better estimate deposited energy, DOI and interaction time (for time-of-flight (TOF) PET) of a gamma ray in a scintillation detector. We developed likelihood models based on either the estimated detection times of individual photoelectrons or the number of photoelectrons in discrete time bins, and applied to two phosphor-coated crystals (LFS and LYSO) used in a previously developed TOF-DOI detector concept. Compared with conventional analytical methods, ML pulse shape discrimination improved DOI encoding by 27% for both crystals. Using the ML DOI estimate, we were able to counter depth-dependent changes in light collection inherent to long scintillator crystals and recover the energy resolution measured with fixed depth irradiation (~11.5% for both crystals). Lastly, we demonstrated how the Richardson-Lucy algorithm, an iterative, ML-based deconvolution technique, can be applied to the digitized waveforms to deconvolve the photodetector's single photoelectron response and produce waveforms with a faster rising edge. After deconvolution and applying DOI and time-walk corrections, we demonstrated a 13% improvement in coincidence timing resolution (from 290 to 254 ps) with the LFS crystal and an 8% improvement (323 to 297 ps) with the LYSO crystal.

INTRACELLULAR LOCALIZATION AND QUANTITATION OF TRITIATED ANTIGENS IN RETICULOENDOTHELIAL TISSUES OF MICE DURING SECONDARY AND HYPERIMMUNE RESPONSES

PubMed Central

Roberts, Audrey N.; Haurowitz, Felix

1962-01-01

Autoradiography and quantitative radiochemical techniques have been used to determine intracellular localization of tritium and the quantity of tissue-bound tritium, respectively, following injections of H3-aniline azo PGG or H3-arsanilazo PGG to yield hyperimmune or secondary response stimulation in mice. Autoradiography revealed intracytoplasmic localization of grains in macrophages of spleen and lung sections, and in Kupffer cells of liver sections following intravenous and subcutaneous injections of H3-aniline azo PGG. Quantitation of tissue section surface radioactivities in the windowless flow counter and scintillation counter, and of dissolved tissue section activities in the scintillation counter, showed that greatest radioactivity was present in lung tissue, with less in spleen, liver, and mesenteric lymph nodes from these hyperimmunized mice. Autoradiographic studies on tissue sections from mice in secondary response stimulation after subcutaneous foot-pad injections of H3-arsanilazo PGG, showed intracellular and extracellular grains over regional popliteal node sections, with intracytoplasmic grain localization over macrophages and pyroninophilic plasmacytes. Scattered macrophages in spleen and lung sections also contained intracytoplasmic radioactivity. Clusters of antibody-synthesizing cells in the regional lymph nodes were demonstrated with fluorescence microscopy, and these cells were compared to similar cells possessing radioactivity as observed in the section autoradiographs. An occasional Russell body plasma cell containing specific antibody was observed in splenic impressions. Windowless flow counting showed that greatest radioactivity was in regional node sections, with less in spleen and lung, and none in contralateral lymph nodes. A quantitative comparison between windowless flow counting and autoradiography revealed that 20 counts were required to yield one silver grain. PMID:13974279

Search for tachyons associated with extensive air showers in the ground level cosmic radiation

NASA Technical Reports Server (NTRS)

Masjed, H. F.; Ashton, F.

1985-01-01

Events detected in a shielded plastic scintillation counter occurring in the 26 microsec preceding the arrival of an extensive air shower at ground level with local electron density or = 20 m to the -2 power and the 240 microsec after its arrival have been studied. No significant excess of events (tachyons) arriving in the early time domain have been observed in a sample of 11,585 air shower triggers.

Telescope Array Results on UHE Cosmic Rays and the Plan

NASA Astrophysics Data System (ADS)

Sagawa, Hiroyuki

The Telescope Array (TA) is the largest experiment in the Northern Hemisphere studying the origin and nature of ultra-high-energy cosmic rays. The TA detector consists of a surface array of 507 scintillation counters covering approximately 700 km2, and 38 fluorescence telescopes located at three sites looking over the surface array. Here, recent TA results using the first five years of data and our ongoing and near-future plans are presented.

Nuclear Science Symposium, 23rd, Scintillation and Semiconductor Counter Symposium, 15th, and Nuclear Power Systems Symposium, 8th, New Orleans, La., October 20-22, 1976, Proceedings

NASA Technical Reports Server (NTRS)

Wagner, L. J.

1977-01-01

The volume includes papers on semiconductor radiation detectors of various types, components of radiation detection and dosimetric systems, digital and microprocessor equipment in nuclear industry and science, and a wide variety of applications of nuclear radiation detectors. Semiconductor detectors of X-rays, gamma radiation, heavy ions, neutrons, and other nuclear particles, plastic scintillator arrays, drift chambers, spark wire chambers, and radiation dosimeter systems are reported on. Digital and analog conversion systems, digital data and control systems, microprocessors, and their uses in scientific research and nuclear power plants are discussed. Large-area imaging and biomedical nucleonic instrumentation, nuclear power plant safeguards, reactor instrumentation, nuclear power plant instrumentation, space instrumentation, and environmental instrumentation are dealt with. Individual items are announced in this issue.

Development of a real-time radon monitoring system for simultaneous measurements in multiple sites

NASA Astrophysics Data System (ADS)

Yamamoto, S.; Yamasoto, K.; Iida, T.

1999-12-01

A real-time radon monitoring system that can simultaneously measure radon concentrations in multiple sites was developed and tested. The system consists of maximum of four radon detectors, optical fiber cables and a data acquisition personal computer. The radon detector uses a plastic scintillation counter that collects radon daughters in the chamber electrostatically. The applied voltage on the photocathode for the photomultiplier tube (PMT) acts as an electrode for radon daughters. The thickness of the plastic scintillator was thin, 50 /spl mu/m, so as to minimize the background counts due to the environmental gamma rays or beta particles. The energy discriminated signals from the radon detectors are fed to the data acquisition personal computer via optical fiber cables. The system made it possible to measure the radon concentrations in multiple sites simultaneously.

The homestake surface-underground scintillators: Initial results

NASA Technical Reports Server (NTRS)

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

1986-01-01

The first 70 tons of the 140-ton Large Area Scintillation Detector (LASD) have been operating since Jan. 1985 at a depth of 4850 ft. (4200 m.w.e.) in the Homestake Gold Mine, Lead, S.D. A total of 4 x 10(4) high-energy muons (E sub mu is approx. 2.7 TeV at the surface) have been detected. The remainder of the detector is scheduled to be in operation by the Fall of 1985. In addition, a surface air shower array is under construction. The first 27 surface counters, spaced out over an area of 270' x 500', began running in June, 1985. The LASD performance, the potential of the combined shower array and underground muon experiment for detecting point sources, and the initial results of a search for periodic emission from Cygnus X-3 are discussed.

Application of large area SiPMs for the readout of a plastic scintillator based timing detector

NASA Astrophysics Data System (ADS)

Betancourt, C.; Blondel, A.; Brundler, R.; Dätwyler, A.; Favre, Y.; Gascon, D.; Gomez, S.; Korzenev, A.; Mermod, P.; Noah, E.; Serra, N.; Sgalaberna, D.; Storaci, B.

2017-11-01

In this study an array of eight 6 mm × 6 mm area SiPMs was coupled to the end of a long plastic scintillator counter which was exposed to a 2.5 GeV/c muon beam at the CERN PS. Timing characteristics of bars with dimensions 150 cm × 6 cm × 1 cm and 120 cm × 11 cm × 2.5 cm have been studied. An 8-channel SiPM anode readout ASIC (MUSIC R1) based on a novel low input impedance current conveyor has been used to read out and amplify SiPMs independently and sum the signals at the end. Prospects for applications in large-scale particle physics detectors with timing resolution below 100 ps are provided in light of the results.

$pi$$sup +-$ TRACKS IN A FILAMENT SCINTILLATION CHAMBER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reynolds, G.T.; Swanson, R.A.; Scarl, D.B.

1960-09-01

The performance of a filament scintillation chamber system designed for studies on stopping mesons was studied by exposing it to the 90-Mev pi/sup plus or minus/ beam of the Nevis cyclotron and taking a total of 16,000 photographs. THe results indicate that (1) except for meson tracks, the chamber appears clean even without the 200-mu sec gating and the iron blockhouse, (2) the magnetic field has no effect on the performance and resolution, (3) three or four tracks can appear in a single picture of the 1-in.-diameter chamber without confusion, and (4) even at the highest beam fluxes, the gatingmore » restricts the tracks to those selected by the counter system. Pictures of the distinguishable stopping of pi/ sup +/ and pi/sup -/ mesons are included. (D.L.C.)« less

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

NASA Astrophysics Data System (ADS)

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

2016-08-01

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, H.

We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy pulsed narrow band neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We also report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median applied electric fields from 0more » to 970 V/cm. For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V/cm. Furthermore, we report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from 83mKr internal conversion electrons is comparable to that from 207Bi conversion electrons, we obtained the numbers of excitons (N ex) and ion pairs (N i) and their ratio (N ex/N i) produced by nuclear recoils from 16.9 to 57.3 keV. Motivated by arguments suggesting direction sensitivity in LAr-TPC signals due to columnar recombination, a comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field is presented for the first time.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fanchon, L; Russell, J; Dogan, S

Purpose: Genetic profiling of biopsied tissue is the basis for personalized cancer therapy. However biopsied materials may not contain sufficient amounts of DNA needed for analysis. We propose a method to determine the adequacy of specimens for performing genetic profiling by quantifying metabolic activity. Methods: We measured the response of two radiation detectors to the activity contained in the minimum amount of tumor cells needed for genetic profiling in biopsy specimens obtained under 2-deoxy-2-({sup 18}F)fluoro-D-glucose ({sup 18}F-FDG) PET/CT guidance. The expected tumor cell concentration in biopsy specimens was evaluated from the amount of DNA needed (∼100 µg) and the numbermore » of pathology sections typically used for the analysis. The average {sup 18}F-FDG uptake per cell was measured by incubating KPC-4662 pancreatic tumor cells and HT-29 colorectal adenocarcinoma tumor cells in {sup 18}F-FDG containing solution (activity concentrations between 0.0122 and 1.51 MBq/mL and glucose concentrations of 3.1 and 1 g/L) for 1 to 1.75 hours and then measuring the activity of a known number of cells. Measurements of surrogate specimens obtained using 18G needle biopsies of gels containing these cells in expected concentrations (∼10{sup 4} µL{sup −1}) were performed using an autoradiography CCD based device (up to 20 min exposure) and a scintillation well counter (∼1 min measurements) about 3 and 5 hours after the end of incubation respectively. Results: At start of autoradiography there were between 0.16 and 1.5 {sup 18}F-FDG molecules/cell and between 1.14 and 5.43×10{sup 7} {sup 18}F-FDG molecules/mL. For the scintillation well counter, sample to minimum-detectable-count rate ratios were greater than 7 and the counting error was less than 25% for ≤80 s measurement times. Images of the samples were identifiable on the autoradiograph for ∼10 min and longer exposure times. Conclusion: Scintillation well counter measurements and CCD based autoradiography have adequate sensitivity to detect the tumor burden needed for genetic profiling in 18G core needle biopsies. Supported in part through the NIH/NCI Cancer Center Support Grant P30 CA008748 and by a sponsored research agreement with Biospace Lab S.A.« less

Advances in solar and cosmic X-ray astronomy - A survey of experimental techniques and observational results.

NASA Technical Reports Server (NTRS)

Hoover, R. B.; Thomas, R. J.; Underwood, J. H.

1972-01-01

The current status of X-ray astronomy is surveyed by reviewing observational results and theoretical conclusions gained within the past two years in areas dealing with the quiet-sun, slowly-varying, and burst components of solar X-radiation and with the features of cosmic X-ray sources. Thermal and nonthermal processes responsible for a wide variety of X-ray emission mechanisms in nature are explained, and characteristics of X radiation from specific solar structures are described. Attention is given to the effects of interstellar and intergalactic matter on cosmic X-rays; the properties of galactic and extragalactic X-ray sources; and the specifications of such instruments as gas-filled ionization detectors, proportional counters, Geiger counters, scintillation detectors, photoelectric detectors, polarimeters, collimators, spectrometers, and imaging systems.

Radioactivity observed in scintillation counters during the HEAO-1 mission

NASA Technical Reports Server (NTRS)

Gruber, D. E.; Jung, G. V.; Matteson, J. L.

1989-01-01

Results are reported from an analysis of radioactivity induced in the NaI medium-energy detector of the hard X-ray and low-energy gamma-ray experiment during the HEAO-1 satellite mission (1977-1978). Consideration is given to the instrument characteristics, the origin and variability of background, and the separation of cosmic-ray activity from the internal activity due to South Atlantic Anomaly trapped protons. Energy spectra and tables listing the nuclide identifications are provided.

New CHOD detector for the NA62 experiment at CERN

NASA Astrophysics Data System (ADS)

Fedotov, S. A.; Kleymenova, A. A.; Khotjantsev, A. N.

2018-01-01

The New CHOD is a scintillation hodoscope with a pad structure featuring a total of 148 counters. The signal from each pad is read out using wavelength-shifting fibers and two or four SensL SiPMs with a sensitive area of 3 × 3 mm2. This photodetector has 4774 pixels 35 × 35 μm2 in size. The key parameters (photon detection efficiency, dark current, crosstalk, and gain) were measured for 500 SiPMs.

Spatial fragment distribution from a therapeutic pencil-like carbon beam in water.

PubMed

Matsufuji, Naruhiro; Komori, Masataka; Sasaki, Hitomi; Akiu, Kengo; Ogawa, Masako; Fukumura, Akifumi; Urakabe, Eriko; Inaniwa, Taku; Nishio, Teiji; Kohno, Toshiyuki; Kanai, Tatsuaki

2005-07-21

The latest heavy ion therapy tends to require information about the spatial distribution of the quality of radiation in a patient's body in order to make the best use of any potential advantage of swift heavy ions for the therapeutic treatment of a tumour. The deflection of incident particles is described well by Molière's multiple-scattering theory of primary particles; however, the deflection of projectile fragments is not yet thoroughly understood. This paper reports on our investigation of the spatial distribution of fragments produced from a therapeutic carbon beam through nuclear reactions in thick water. A DeltaE-E counter telescope system, composed of a plastic scintillator, a gas-flow proportional counter and a BGO scintillator, was rotated around a water target in order to measure the spatial distribution of the radiation quality. The results revealed that the observed deflection of fragment particles exceeded the multiple scattering effect estimated by Molière's theory. However, the difference can be sufficiently accounted for by considering one term involved in the multiple-scattering formula; this term corresponds to a lateral 'kick' at the point of production of the fragment. This kick is successfully explained as a transfer of the intra-nucleus Fermi momentum of a projectile to the fragment; the extent of the kick obeys the expectation derived from the Goldhaber model.

Optical fibre luminescence sensor for real-time LDR brachytherapy dosimetry

NASA Astrophysics Data System (ADS)

Woulfe, P.; Sullivan, F. J.; O'Keeffe, S.

2016-05-01

An optical fibre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical fibre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical fibre sensor is presented, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 250μm of a 500μm plastic optical fibre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for brachytherapy, in prostate cancer treatment, providing oncologists with real-time information of the radiation dose to the target area and/or nearby critical structures. The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the fibre, propagating along the optical fibre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to Iodine-125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

Optical fibre luminescence sensor for real-time LDR brachytherapy dosimetry

NASA Astrophysics Data System (ADS)

Woulfe, P.; O'Keeffe, S.; Sullivan, F. J.

2018-02-01

An optical fibre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical fibre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical fibre sensor is developed, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 700μm of a 1mm plastic optical fibre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for low dose rate (LDR) brachytherapy, in prostate cancer treatment, providing radiation oncologists with real-time information of the radiation dose to the target area and/or nearby organs at risk (OARs). The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the fibre, propagating along the optical fibre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to 0.397mCi of Iodine125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

Liquid xenon calorimeter for MEG II experiment with VUV-sensitive MPPCs

NASA Astrophysics Data System (ADS)

Ogawa, Shinji; MEG II Collaboration

2017-02-01

The MEG II experiment is an upgrade of the MEG experiment to search for the charged lepton flavor violating decay of muon, μ+ →e+ γ . The MEG II experiment is expected to reach a branching ratio sensitivity of 4 ×10-14 , which is one order of magnitude better than the sensitivity of the current MEG experiment. The performance of the liquid xenon (LXe) γ-ray detector will be greatly improved with a highly granular scintillation readout realized by replacing 216 photomultiplier tubes (PMTs) on the γ-ray entrance face with 4092 Multi-Pixel Photon Counters (MPPCs). For this purpose, we have developed a new type of MPPC which is sensitive to the LXe scintillation light in vacuum ultraviolet (VUV) range, in collaboration with Hamamatsu Photonics K.K. We have measured the performance of the MPPC in LXe, and an excellent performance has been confirmed including high photon detection efficiency (> 15 %) for LXe scintillation light. An excellent performance of the LXe detector has been confirmed by Monte Carlo simulations based on the measured properties of the MPPC. The construction of the detector is in progress, aiming to start physics data taking in 2017.

A Hybrid Gas Detector/Phoswich for Hard X-ray Astronomy

NASA Technical Reports Server (NTRS)

Ramsey, B. D.; Austin, R. A.; Minamitani, T.; Weisskopf, M. C.; Grindlay, J. E.; Lum, K. S. K.; Manandhar, R. P.

1993-01-01

A hybrid detector, which combines an optical avalanche chamber with a phoswich, is currently under development. The optical avalanche chamber - a proportional counter designed to give large quantities of light photons during charge multiplication, mounts on the front of the scintillator and gives response at low energies, while the solid scintillator takes over at energies where the gas becomes transparent (greater than 90 keV). Both sections of the hybrid will be read out by a common set of photomultipliers under the phoswich. The addition of the gas section to the phoswich improves the energy resolution of the instrument by a factor of 2.5 at 25 keV and the spatial resolution by a factor of 10 at the same energy. The net result is an instrument with broad band coverage and high sensitivity which will be used for coded aperture imaging on long duration balloon flights.

Fast neutron detection with a segmented spectrometer

NASA Astrophysics Data System (ADS)

Langford, T. J.; Bass, C. D.; Beise, E. J.; Breuer, H.; Erwin, D. K.; Heimbach, C. R.; Nico, J. S.

2015-01-01

A fast neutron spectrometer consisting of segmented plastic scintillator and 3He proportional counters was constructed for the measurement of neutrons in the energy range 1-200 MeV. We discuss its design, principles of operation, and the method of analysis. The detector is capable of observing very low neutron fluxes in the presence of ambient gamma background and does not require scintillator pulse-shape discrimination. The spectrometer was characterized for its energy response in fast neutron fields of 2.5 MeV and 14 MeV, and the results are compared with Monte Carlo simulations. Measurements of the fast neutron flux and energy response at 120 m above sea-level (39.130°N, 77.218°W) and at a depth of 560 m in a limestone mine are presented. Finally, the design of a spectrometer with improved sensitivity and energy resolution is discussed.

Design and characterization of a real time particle radiography system based on scintillating optical fibers

NASA Astrophysics Data System (ADS)

Longhitano, F.; Lo Presti, D.; Bonanno, D. L.; Bongiovanni, D. G.; Leonora, E.; Randazzo, N.; Reito, S.; Sipala, V.; Gallo, G.

2017-02-01

The fabrication and characterization of a charged particle imaging system composed of a tracker and a residual range detector (RRD) is described. The tracker is composed of four layers of scintillating fibers (SciFi), 500 μm side square section, arranged to form two planes orthogonal to each other. The fibers are coupled to two Multi-Pixel Photon Counter (MPPC) arrays by means of a channel reduction system patented by the Istituto Nazionale di Fisica Nucleare (INFN) (Presti, 2015) [1]. Sixty parallel layers of the same fibers used in the tracker compose the RRD. The various layers are optically coupled to a MPPC array by means of wavelength shifting (WLS) fibers. The sensitive area of the two detectors is 9×9 cm2. The results of the measurements, acquired by the prototypes with CATANA (Cirrone, 2008) [2] proton beam, and a comparison with the simulations of the detectors are presented.

Cosmic ray scintillations in the frequency range from 0.00001 to 0.01 Hz

NASA Technical Reports Server (NTRS)

Gehrels, N.; Lheureux, J.

1978-01-01

Power spectra of the flux variations in cosmic rays of energy greater than a few GeV are presented. The data were obtained at balloon altitudes (40-45 km) from two scintillation-type detectors flown for six hours from Palestine, Texas, on November 4, 1972. The large area detectors had effective count rates up to 2000 cps setting the Poisson noise level in the power spectra of the relative fluctuations at 0.001/Hz. The analysis was made on the singles rate of each of the counters as well as on the coincidence rates between them. In all cases, the spectra between 0.0001 and 0.002 Hz are power laws in frequency of the form f to the exponent negative gamma, where gamma is between 1.5 and 2.0. No significant peaks in the range 0.0001 to 0.01 Hz are observed.

Application of the Strong Scatter Theory to the Interpretation of Ionospheric Scintillation Measurements along Geostationary Satellite Links at VHF and L-band

NASA Astrophysics Data System (ADS)

Carrano, C. S.; Groves, K. M.; Basu, S.; Mackenzie, E.; Sheehan, R. E.

2013-12-01

In a previous work, we demonstrated that ionospheric turbulence parameters may be inferred from amplitude scintillations well into in the strong scatter regime [Carrano et al., International Journal of Geophysics, 2012]. This technique, called Iterative Parameter Estimation (IPE), uses the strong scatter theory and numerical inversion to estimate the parameters of an ionospheric phase screen (turbulent intensity, phase spectral index, and irregularity zonal drift) consistent with the observed scintillations. The optimal screen parameters are determined such that the theoretical intensity spectrum on the ground best matches the measured intensity spectrum in a least squares sense. We use this technique to interpret scintillation measurements collected during a campaign at Ascension Island (7.96°S, 14.41°W) in March 2000, led by Santimay Basu and his collaborators from Air Force Research Laboratory. Geostationary satellites broadcasting radio signals at VHF and L-band were monitored along nearly co-linear links, enabling a multi-frequency analysis of scintillations with the same propagation geometry. The VHF data were acquired using antennas spaced in the magnetic east-west direction, which enabled direct measurement of the zonal irregularity drift. We show that IPE analysis of the VHF and L-Band scintillations, which exhibited very different statistics due to the wide frequency separation, yields similar estimates of the phase screen parameters that specify the disturbed ionospheric medium. This agreement provides confidence in our phase screen parameter estimates. It also suggests a technique for extrapolating scintillation measurements to frequencies other than those observed that is valid in the case of strong scatter. We find that IPE estimates of the zonal irregularity drift, made using scintillation observations along single space-to-ground link, are consistent with those measured independently using the spaced antenna technique. This encouraging result suggests one may measure the zonal irregularity drift at scintillation monitoring stations equipped with only a single channel receiver, so that the spaced-antenna technique cannot be employed. We noted that the scintillation index (S4) at L-band commonly exceeded that at VHF early in the evening when the irregularities were most intense, followed by one or more reversals of this trend at later local times as aging irregularities decayed and newly formed bubbles drifted over the station. We use the strong scatter theory to explain this perhaps counter-intuitive situation (one would normally expect a higher S4 at the lower frequency) in terms of strong refractive focusing.

Novel laser-processed CsI:Tl detector for SPECT

PubMed Central

Sabet, H.; Bläckberg, L.; Uzun-Ozsahin, D.; El-Fakhri, G.

2016-01-01

Purpose: The aim of this work is to demonstrate the feasibility of a novel technique for fabrication of high spatial resolution CsI:Tl scintillation detectors for single photon emission computed tomography systems. Methods: The scintillators are fabricated using laser-induced optical barriers technique to create optical microstructures (or optical barriers) inside the CsI:Tl crystal bulk. The laser-processed CsI:Tl crystals are 3, 5, and 10 mm in thickness. In this work, the authors focus on the simplest pattern of optical barriers in that the barriers are created in the crystal bulk to form pixel-like patterns resembling mechanically pixelated scintillators. The monolithic CsI:Tl scintillator samples are fabricated with optical barrier patterns with 1.0 × 1.0 mm2 and 0.625 × 0.625 mm2 pixels. Experiments were conducted to characterize the fabricated arrays in terms of pixel separation and energy resolution. A 4 × 4 array of multipixel photon counter was used to collect the scintillation light in all the experiments. Results: The process yield for fabricating the CsI:Tl arrays is 100% with processing time under 50 min. From the flood maps of the fabricated detectors exposed to 122 keV gammas, peak-to-valley (P/V) ratios of greater than 2.3 are calculated. The P/V values suggest that regardless of the crystal thickness, the pixels can be resolved. Conclusions: The results suggest that optical barriers can be considered as a robust alternative to mechanically pixelated arrays and can provide high spatial resolution while maintaining the sensitivity in a high-throughput and cost-effective manner. PMID:27147372

Improving Depth, Energy and Timing Estimation in PET Detectors with Deconvolution and Maximum Likelihood Pulse Shape Discrimination

PubMed Central

Berg, Eric; Roncali, Emilie; Hutchcroft, Will; Qi, Jinyi; Cherry, Simon R.

2016-01-01

In a scintillation detector, the light generated in the scintillator by a gamma interaction is converted to photoelectrons by a photodetector and produces a time-dependent waveform, the shape of which depends on the scintillator properties and the photodetector response. Several depth-of-interaction (DOI) encoding strategies have been developed that manipulate the scintillator’s temporal response along the crystal length and therefore require pulse shape discrimination techniques to differentiate waveform shapes. In this work, we demonstrate how maximum likelihood (ML) estimation methods can be applied to pulse shape discrimination to better estimate deposited energy, DOI and interaction time (for time-of-flight (TOF) PET) of a gamma ray in a scintillation detector. We developed likelihood models based on either the estimated detection times of individual photoelectrons or the number of photoelectrons in discrete time bins, and applied to two phosphor-coated crystals (LFS and LYSO) used in a previously developed TOF-DOI detector concept. Compared with conventional analytical methods, ML pulse shape discrimination improved DOI encoding by 27% for both crystals. Using the ML DOI estimate, we were able to counter depth-dependent changes in light collection inherent to long scintillator crystals and recover the energy resolution measured with fixed depth irradiation (~11.5% for both crystals). Lastly, we demonstrated how the Richardson-Lucy algorithm, an iterative, ML-based deconvolution technique, can be applied to the digitized waveforms to deconvolve the photodetector’s single photoelectron response and produce waveforms with a faster rising edge. After deconvolution and applying DOI and time-walk corrections, we demonstrated a 13% improvement in coincidence timing resolution (from 290 to 254 ps) with the LFS crystal and an 8% improvement (323 to 297 ps) with the LYSO crystal. PMID:27295658

Tritium volume activity in the Baltic Sea in 1987-1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Styro, D.B.; Korotkov, V.P.

Tritium volume activities measured in the Baltic Sea are summarized in this paper. Activity levels were determined by the liquid scintillation method with a LS-1000 counter. The field investigations showed that the tritium volume activity in the Baltic Sea can change substantially in absolute magnitude. Therefore, average volume activity is used as an indicator of natural content. Correlations between calculated (averaged) tritium activity levels and the Chernobyl accident are very briefly discussed. 7 refs., 2 figs., 1 tab.

Character of energy flow in air shower core

NASA Technical Reports Server (NTRS)

Mizushima, K.; Asakimori, K.; Maeda, T.; Kameda, T.; Misaki, Y.

1985-01-01

Energy per charged particle near the core of air showers was measured by 9 energy flow detectors, which were the combination of Cerenkov counters and scintillators. Energy per particle of each detector was normalized to energy at 2m from the core. The following results were obtained as to the energy flow: (1) integral frequency distribution of mean energy per particle (averaged over 9 detectors) is composed of two groups separated distinctly; and (2) showers contained in one group show an anisotropy of arrival direction.

CONTROL CONSOLE FOR MTR FISSION PRODUCT MONITOR, USED TO DETECT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

CONTROL CONSOLE FOR MTR FISSION PRODUCT MONITOR, USED TO DETECT BREAKS IN CLADDING OF FUEL ELEMENTS. COUNT-RATE METER IN TOP PANEL INDICATES AMOUNT OF RADIOACTIVITY. LOWER PANELS SUPPLY POWER AND AMPLIFICATION OF SIGNALS GENERATED BY SCINTILLATION COUNTER/PHOTOMULTIPLIER TUBE COMBINATION IN RESPONSE TO RADIOACTIVITY IN A SAMPLE OF THE COOLING WATER. INL NEGATIVE NO. 56-771. Jack L. Anderson, Photographer, 3/15/1956. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

DISPOSITION OF THE INNER RADIATION BELT AND MAGNETIC FIELD OF THE EARTH

DOE Office of Scientific and Technical Information (OSTI.GOV)

GORCHAKOV, IE. V.

1963-02-01

A scintillation counter on Sputnik III was used to conduct ionization measurement in a sodium iodide crystal and register the number of events releasing more than 35 kev in the crystal. The boundary of the inner radiation belt shows a strong longitudinal effect. The observed dependence on longitude of the boundary was explained by the fact that the inner belt consists of particles captured by the geomagnetic field and constitutes a noncentral dipole field. (C.E.S.)

Communicable Disease Research

NASA Technical Reports Server (NTRS)

1982-01-01

The COSMIC program FITLOS is used regularly by the Centers for Disease Control (CDC), for analyzing data from radioimmunoassays, which involve testing human body substances to provide information on how deficits or excesses of those substances affect a body's ability to ward off disease. A liquid scintillation counter's data is analyzed by the FITLOS program. FITLOS data, then aids in establishing reference methods for hospitals and other health laboratories in their radioimmunoassays. CDC's use of this program enabled them to avoid the cost of designing and developing a new program.

Results from the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Jui, Charles C. H.; Telescope Array Collaboration

2016-04-01

The Telescope Array (TA) is the largest ultrahigh energy cosmic ray detector in the northern hemisphere. The experiment consists of three fluorescence stations viewing the air space over a surface array of 507 scintillation counters deployed over 700 square kilometers. TA has been in operation since 2008. The most recent results from TA, including that of composition studies and search for arrival direction anisotropy, will be presented. We will also report on the progress of the new TA low energy extension (TALE).

Subthreshold neutron interrogator for detection of radioactive materials

DOEpatents

Evans, Michael L.; Menlove, Howard O.; Baker, Michael P.

1980-01-01

A device for detecting fissionable material such as uranium in low concentrations by interrogating with photoneutrons at energy levels below 500 keV, and typically about 26 keV. Induced fast neutrons having energies above 500 keV by the interrogated fissionable material are detected by a liquid scintillator or recoil proportional counter which is sensitive to the induced fast neutrons. Since the induced fast neutrons are proportional to the concentration of fissionable material, detection of induced fast neutrons indicate concentration of the fissionable material.

Development of a Beam Trajectory Monitoring System Using e+/e- Pair Production Events

NASA Astrophysics Data System (ADS)

Kimura, Shota; Emoto, Yusaku; Fujihara, Kento; Ito, Hiroshi; Kawai, Hideyuki; Kobayashi, Atsushi; Mizuno, Takahiro

2018-01-01

In particle therapy, it is important to monitor the Bragg-peak position. It was simulated by GEANT4 Monte Carlo Simulation Code that the distribution of secondary generated gamma rays on the carbon beam therapy and the proton beam therapy. This simulation shows that gamma rays whose energy is 10 MeV or more are intensively generated at the Bragg-peak position. We are developing the system to monitor the Bragg-peak position which can measure pair production events occurred in the detector by gamma rays from irradiation points. The momentum direction of the gamma ray can be determined by measuring passing points and energy of e+ and e- generated by pair production. This system has 5 parts. The first is the conversion part. This part consists of several layers. Each layer is composed of a La-GPS ((Gd0.75La0.24Ce0.01)2Si2O7) scintillator plate and wavelength-shifting fibre (WLSF) sheets. The scintillator plate is sandwiched between sheets, where the directions of the sheets are in orthogonally x and y directions. In this part, gamma rays are converted to e+ e- pairs and the position where the conversion occured is determined. The second is the tracking part. This part consists of 2 layers of scintillating fibre tracker. Each layer has 6 scintillating fibre sheets for x, x', u, u', v, and v'. The third is the energy measurement part. It measures the energy of e+ and e- by scintillator array and Silicon Photomultipliers. The fourth is the veto counter for bremsstrahlung gamma rays from e+ and e-. The fifth is the beam monitor. By experiment, the number of photoelectrons of La-GPS with a WLSF (B-3(300)MJ, Kuraray) sheet and scintillating fibre (SCSF-78, Kuraray) when charged particle passed was measured as 9.7 and 7.6 respectively.

Evaluation of Position Resolution for a Prototype Whole-Body PET Detector Based on Suppressing Backgrounds by Compton Scattering

NASA Astrophysics Data System (ADS)

Fujihara, Kento; Emoto, Yusaku; Ito, Hiroshi; Kaneko, Naomi; Kaneko, Hideyuki; Kawai, Hideyuki; Kobayashi, Atsushi; Mizuno, Takahiro

2018-01-01

Existing PET (Positron Emission Tomography) systems make clear images in demonstration (measuring small PET reagent in pure water), however images in real diagnosis become unclear. The authors suspected that this problem was caused by Compton scattering in a detector. When PET systems observe plural photomultiplier tube outputs, an original emission point is regarded as centroid of the outputs. However, even if plural emission in Compton scattering occur, these systems calculate original point in the same way as single emission. Therefore, the authors considered that rejecting Compton scattering events makes PET systems much better, and made prototype counter. Main components of the prototype counter are plate-like high-growth-rate (HGR) La-GPS scintillators and wavelength shifting fibers (WLSF). HGR crystals grow 10 times as fast as a mono-crystal (a normal mono-crystal grows at 2 - 3 mm an hour). Thus, it includes microbubble and its transparency get worth. Consequently, HGR crystals usually are not used in radiation measuring instruments. However, this time they are used on the purpose. Because of their low transparency, scintillation lights come out right above and right under of emission position. Therefore, Compton scattering events is rejected easily. The prototype detector has an effective area of 300 by 300 square mm. The detector consists of 24 layers. One layer consists of HGR La-GPS scintillator of 1 mm thickness. Top and bottom surface of scintillator were covered by dual sheets of WLSF with a diameter of 0.2 mm. Sheets of WLSF on top and bottom of the scintillator make a right angle with each other, and measure X- and Y-components. Z-component is measured by difference of WLSF outputs between top and bottom. If plural layers output signals, this counter regards the event as Compton scattering event, and reject the event. Even if only a layer output signals, the event is rejected when number output signals from WLSF is more than 1.5 times of single emission. Material cost of this system is, 0.2M for HGR La-GPS, 0.03M for WLSF, 0.03M for 600 units of 6 by 6 mm SiPM's, 0.12M for 12000 units of 1 by 1 mm SiPM's, and 0.09M for 1800 channel of signal readout circuits. Considering total cost, price of this PET will be set 1M or less. This idea was confirmed with numerical simulation and experimentation. In experimentation, position resolution in photoelectric absorption was 0.2 mm, and minimum distance that this detector could recognize plural emission in Compton scattering was 1 mm. In parallel, three kinds of model were made: a prototype detector, all the signals readout method, and resistance delay method. Simulation setting was 2 MBq/L in normal tissue and 10 MBq/L in cancer. As a result of simulation, a prototype detector identified 3 mm cancer, however the others made unclear image and was not able to identified cancer. That is to say, the prototype detector is able to reject Compton scattering events and inexpensive. Therefore, whole-body PET system with this detector must diagnose cancer with a diameter of 3 mm or more and be priced 1M or less

Status and performance of the AS array of the Tibet AS sub. gamma. experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amenomori, M.; Bai, Z.W.; Cao, Z.

1991-04-05

The Tibet AS{gamma} experiment, which has started since January, 1990, is located at an altitude of 4,300m at Yangbaging in Tibet, China (90.5{degree} E, 301{degree} N). The air-shower array is composed of 49 scintillation counters for fast timing (FT), each counter having an area of 0.5 m{sup 2}, in a grid pattern with a spacing of 15 m and 16 density detectors. The density detectors surrounding the FT detectors are planned to select the showers of which core are inside the FT array. For the constant and continuous opeation, the system for laser calibration, the ADC,TDC module calibration and themore » power check system were installed. A Rb clock is used for the phase analysis of {gamma}-rays.« less

High resolution phoswich gamma-ray imager utilizing monolithic MPPC arrays with submillimeter pixelized crystals

NASA Astrophysics Data System (ADS)

Kato, T.; Kataoka, J.; Nakamori, T.; Kishimoto, A.; Yamamoto, S.; Sato, K.; Ishikawa, Y.; Yamamura, K.; Kawabata, N.; Ikeda, H.; Kamada, K.

2013-05-01

We report the development of a high spatial resolution tweezers-type coincidence gamma-ray camera for medical imaging. This application consists of large-area monolithic Multi-Pixel Photon Counters (MPPCs) and submillimeter pixelized scintillator matrices. The MPPC array has 4 × 4 channels with a three-side buttable, very compact package. For typical operational gain of 7.5 × 105 at + 20 °C, gain fluctuation over the entire MPPC device is only ± 5.6%, and dark count rates (as measured at the 1 p.e. level) amount to <= 400 kcps per channel. We selected Ce-doped (Lu,Y)2(SiO4)O (Ce:LYSO) and a brand-new scintillator, Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) due to their high light yield and density. To improve the spatial resolution, these scintillators were fabricated into 15 × 15 matrices of 0.5 × 0.5 mm2 pixels. The Ce:LYSO and Ce:GAGG scintillator matrices were assembled into phosphor sandwich (phoswich) detectors, and then coupled to the MPPC array along with an acrylic light guide measuring 1 mm thick, and with summing operational amplifiers that compile the signals into four position-encoded analog outputs being used for signal readout. Spatial resolution of 1.1 mm was achieved with the coincidence imaging system using a 22Na point source. These results suggest that the gamma-ray imagers offer excellent potential for applications in high spatial medical imaging.

QUENCH: A software package for the determination of quenching curves in Liquid Scintillation counting.

PubMed

Cassette, Philippe

2016-03-01

In Liquid Scintillation Counting (LSC), the scintillating source is part of the measurement system and its detection efficiency varies with the scintillator used, the vial and the volume and the chemistry of the sample. The detection efficiency is generally determined using a quenching curve, describing, for a specific radionuclide, the relationship between a quenching index given by the counter and the detection efficiency. A quenched set of LS standard sources are prepared by adding a quenching agent and the quenching index and detection efficiency are determined for each source. Then a simple formula is fitted to the experimental points to define the quenching curve function. The paper describes a software package specifically devoted to the determination of quenching curves with uncertainties. The experimental measurements are described by their quenching index and detection efficiency with uncertainties on both quantities. Random Gaussian fluctuations of these experimental measurements are sampled and a polynomial or logarithmic function is fitted on each fluctuation by χ(2) minimization. This Monte Carlo procedure is repeated many times and eventually the arithmetic mean and the experimental standard deviation of each parameter are calculated, together with the covariances between these parameters. Using these parameters, the detection efficiency, corresponding to an arbitrary quenching index within the measured range, can be calculated. The associated uncertainty is calculated with the law of propagation of variances, including the covariance terms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Observation of fast scintillation of cryogenic PbI/sub 2/ with VLPCs

NASA Astrophysics Data System (ADS)

Moses, W. W.; Choong, W.-S.; Derenzo, S. E.; Bross, A. D.; Dysert, R.; Rykalin, V. V.; Shah, K. S.; Klugerman, M.

2004-10-01

At cryogenic temperatures (/spl sim/10 K), undoped lead iodide (PbI/sub 2/) has material and scintillation properties that are very attractive for positron emission tomography (PET). However, the PbI/sub 2/ emissions are quenched at temperatures >40 K, so close optical coupling between the scintillator and photodetector requires a photodetector that also operates at cryogenic temperatures. This suggests the visible light photon counter (VLPC), which operates at similar temperatures and combines high gain and high quantum efficiency. We proximity couple (0.001 in air gap) PbI/sub 2/ crystals with 1.0-2.5 mm dimensions to a 1 mm diameter VLPC and cool the system to 8.5 K. Signals with short (<10 ns) duration are observed. When excited with 511 keV photons, a coincidence timing resolution of 1.3 ns full-width at half-maximum is measured. While a clear photopeak is observed for 122 keV excitation, no clear photopeak is seen under 511 keV excitation (possibly due to the poor optical quality of the PbI/sub 2/ crystals). While the present configuration must be scaled-up considerably, a cryogenic PbI/sub 2//VLPC combination may eventually become the basis for a practical time-of-flight PET camera.

The FIRST experiment at GSI

NASA Astrophysics Data System (ADS)

Pleskac, R.; Abou-Haidar, Z.; Agodi, C.; Alvarez, M. A. G.; Aumann, T.; Battistoni, G.; Bocci, A.; Böhlen, T. T.; Boudard, A.; Brunetti, A.; Carpinelli, M.; Cirrone, G. A. P.; Cortes-Giraldo, M. A.; Cuttone, G.; De Napoli, M.; Durante, M.; Fernández-García, J. P.; Finck, C.; Golosio, B.; Gallardo, M. I.; Iarocci, E.; Iazzi, F.; Ickert, G.; Introzzi, R.; Juliani, D.; Krimmer, J.; Kurz, N.; Labalme, M.; Leifels, Y.; Le Fevre, A.; Leray, S.; Marchetto, F.; Monaco, V.; Morone, M. C.; Oliva, P.; Paoloni, A.; Piersanti, L.; Quesada, J. M.; Raciti, G.; Randazzo, N.; Romano, F.; Rossi, D.; Rousseau, M.; Sacchi, R.; Sala, P.; Sarti, A.; Scheidenberger, C.; Schuy, C.; Sciubba, A.; Sfienti, C.; Simon, H.; Sipala, V.; Spiriti, E.; Stuttge, L.; Tropea, S.; Younis, H.; Patera, V.

2012-06-01

The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at the SIS accelerator of GSI laboratory in Darmstadt has been designed for the measurement of ion fragmentation cross-sections at different angles and energies between 100 and 1000 MeV/nucleon. Nuclear fragmentation processes are relevant in several fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The start of the scientific program of the FIRST experiment was on summer 2011 and was focused on the measurement of 400 MeV/nucleon 12C beam fragmentation on thin (8 mm) graphite target. The detector is partly based on an already existing setup made of a dipole magnet (ALADiN), a time projection chamber (TP-MUSIC IV), a neutron detector (LAND) and a time of flight scintillator system (TOFWALL). This pre-existing setup has been integrated with newly designed detectors in the Interaction Region, around the carbon target placed in a sample changer. The new detectors are a scintillator Start Counter, a Beam Monitor drift chamber, a silicon Vertex Detector and a Proton Tagger scintillator system optimized for the detection of light fragments emitted at large angles. In this paper we review the experimental setup, then we present the simulation software, the data acquisition system and finally the trigger strategy of the experiment.

Monte Carlo Shower Counter Studies

NASA Technical Reports Server (NTRS)

Snyder, H. David

1991-01-01

Activities and accomplishments related to the Monte Carlo shower counter studies are summarized. A tape of the VMS version of the GEANT software was obtained and installed on the central computer at Gallaudet University. Due to difficulties encountered in updating this VMS version, a decision was made to switch to the UNIX version of the package. This version was installed and used to generate the set of data files currently accessed by various analysis programs. The GEANT software was used to write files of data for positron and proton showers. Showers were simulated for a detector consisting of 50 alternating layers of lead and scintillator. Each file consisted of 1000 events at each of the following energies: 0.1, 0.5, 2.0, 10, 44, and 200 GeV. Data analysis activities related to clustering, chi square, and likelihood analyses are summarized. Source code for the GEANT user subprograms and data analysis programs are provided along with example data plots.

Optimization of analytical laboratory work using computer networking and databasing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Upp, D.L.; Metcalf, R.A.

1996-06-01

The Health Physics Analysis Laboratory (HPAL) performs around 600,000 analyses for radioactive nuclides each year at Los Alamos National Laboratory (LANL). Analysis matrices vary from nasal swipes, air filters, work area swipes, liquids, to the bottoms of shoes and cat litter. HPAL uses 8 liquid scintillation counters, 8 gas proportional counters, and 9 high purity germanium detectors in 5 laboratories to perform these analyses. HPAL has developed a computer network between the labs and software to produce analysis results. The software and hardware package includes barcode sample tracking, log-in, chain of custody, analysis calculations, analysis result printing, and utility programs.more » All data are written to a database, mirrored on a central server, and eventually written to CD-ROM to provide for online historical results. This system has greatly reduced the work required to provide for analysis results as well as improving the quality of the work performed.« less

An experiment to study the nuclear component of primary cosmic rays

NASA Technical Reports Server (NTRS)

Paul, J. M.; Verma, S. D.

1971-01-01

An apparatus has been designed and is being fabricated to study the charge composition, fluxes, and energy spectra of light nuclei in the energy region from 1 GeV to 100 GeV. The apparatus essentially consists of an array of a large number of particle detectors operated in coincidence and serving as a charged particle telescope. A mosaic silicon semiconductor detector, a plastic scintillation counter and a lucite Cerenkov detector are used to measure the charges of the incident nuclei. Two one-inch thick CsI detectors are used to study low energy particles. An ionization spectrometer is utilized to measure primary energies in the 1 to 100 GeV energy interval. A gas Cerenkov counter is being designed to distinguish between electrons and protons. It is planned to calibrate the apparatus at an accelerator using particles of known energy.

Ames collaborative study of cosmic ray neutrons

NASA Technical Reports Server (NTRS)

Hewitt, J. E.; Hughes, L.; Mccaslin, J. B.; Stephens, L. D.; Rindi, A.; Smith, A. R.; Thomas, R. H.; Griffith, R. V.; Welles, C. G.; Baum, J. W.

1976-01-01

The results of a collaborative study to define both the neutron flux and the spectrum more precisely and to develop a dosimetry package that can be flown quickly to altitude for solar flare events are described. Instrumentation and analysis techniques were used which were developed to measure accelerator-produced radiation. The instruments were flown in the Ames Research Center high altitude aircraft. Neutron instrumentation consisted of Bonner spheres with both active and passive detector elements, threshold detectors of both prompt-counter and activation-element types, a liquid scintillation spectrometer based on pulse-shape discrimination, and a moderated BF3 counter neutron monitor. In addition, charged particles were measured with a Reuter-Stokes ionization chamber system and dose equivalent with another instrument. Preliminary results from the first series of flights at 12.5 km (41,000 ft) are presented, including estimates of total neutron flux intensity and spectral shape and of the variation of intensity with altitude and geomagnetic latitude.

Dark-count-less photon-counting x-ray computed tomography system using a YAP-MPPC detector

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Sato, Yuich; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2012-10-01

A high-sensitive X-ray computed tomography (CT) system is useful for decreasing absorbed dose for patients, and a dark-count-less photon-counting CT system was developed. X-ray photons are detected using a YAP(Ce) [cerium-doped yttrium aluminum perovskite] single crystal scintillator and an MPPC (multipixel photon counter). Photocurrents are amplified by a high-speed current-voltage amplifier, and smooth event pulses from an integrator are sent to a high-speed comparator. Then, logical pulses are produced from the comparator and are counted by a counter card. Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan. The image contrast of gadolinium medium slightly fell with increase in lower-level voltage (Vl) of the comparator. The dark count rate was 0 cps, and the count rate for the CT was approximately 250 kcps.

The use of optical fibers in the Trans Iron Galactic Element Recorder (TIGER)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sposato, S. H.; Binns, W. R.; Dowkontt, P. F.

1998-11-09

TIGER, the Trans-Iron Galactic Element Recorder, is a cosmic-ray balloon borne experiment that utilizes a scintillating Fiber Hodoscope/Time of Flight (TOF) counter. It was flown aboard a high altitude balloon on September 24, 1997. The objective of this experiment is to measure the elemental abundances of all nuclei within the charge range: 26{<=}Z{<=}40. This initial balloon flight will test the detector concept, which will be used in future balloon and space experiments. The instrument and the fiber detector are described.

X-ray observations of AM Herculis from OSO-8

NASA Technical Reports Server (NTRS)

Coe, M. J.; Dennis, B. R.; Dolan, J. F.; Crannell, C. J.; Frost, K. J.; Orwig, L. E.

1979-01-01

The white dwarf binary system AM Herculis (2A1815+500) was observed in X-rays at both low energies (E less 10 keV) and higher energies. The exact shape of the spectrum, particularly at the higher energies, has yet to be determined. Results from the high energy scintillation spectrometer on OSO-8 are presented. These are combined with results published elsewhere obtained concurrently with the proportional counter on the same satellite, thereby giving for the first time coincident observations of AM Her over the range 2 to 250 keV.

GLASS COMPOSITION AND PROCESS OF MAKING

DOEpatents

Bishay, A.M.

1962-09-01

Glass compositions are described which are suitable for scintillators of thermal-neutron counters. The glass consists of from 70 to 75 mole% of B/sub 2/O/ sub 3/, from 7 to 9 mole% of Ce/sub 2/O/sub 3/, and from 23 to 16 mole% of Al/sub 2/O/sub 3/ plus Na/sub 2 /O in a mole ratio of 1 to 1.5. The process of making the glass from cerous oxalate, ammonium pentaborate, sodium carbonate, and hydrated alumina in a nonoxidizing atmosphere at 1400-1500 deg C is given. (AEC)

PPO-ethanol system as wavelength shifter for the Cherenkov counting technique using a liquid scintillation counter

NASA Astrophysics Data System (ADS)

Takiue, Makoto; Fujii, Haruo; Ishikawa, Hiroaki

1984-12-01

2, 5-diphenyloxazole (PPO) has been proposed as a wavelength shifter for Cherenkov counting. Since PPO is not incorporated with water, we have introduced the fluor into water in the form of micelle using a PPO-ethanol system. This technique makes it possible to obtain a high Cherenkov counting efficiency under stable sample conditions, attributed to the proper spectrometric features of the PPO. The 32P Cherenkov counting efficiency (68.4%) obtained from this technique is large as that measured with a conventional Cherenkov technique.

Measurement of high-energy prompt gamma-rays from neutron induced fission of U-235

NASA Astrophysics Data System (ADS)

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, Riccardo; Léguillon, Romain; Ogawa, Tatsuhiko; Soldner, Torsten; Hambsch, Franz-Josef; Astier, Alain; Pollitt, Andrew; Petrache, Costel; Tsekhanovich, Igor; Mathieu, Ludovic; Aïche, Mourad; Frost, Robert; Czajkowski, Serge; Guo, Song; Köster, Ulli

2017-09-01

We have developed a new setup to measure prompt γ-rays from the 235U(nth,f) reaction. The setup consists of two multi-wire proportional counters (MWPCs) to detect the fission fragments, two LaBr3(Ce) scintillators to measure the γ-rays. The highly efficient setup was installed at the PF1B beam line of the Institut Laue Langevin (ILL). We have successfully measured the γ-ray spectrum up to about 20 MeV for the fist time in neutron-induced fission.

Xe isotope detection and discrimination using beta spectroscopy with coincident gamma spectroscopy

NASA Astrophysics Data System (ADS)

Reeder, P. L.; Bowyer, T. W.

1998-02-01

Beta spectroscopic techniques show promise of significant improvements for a beta-gamma coincidence counter that is part of a system for analyzing Xe automatically separated from air. The previously developed counting system for 131mXe, 133mXe, 133gXe, and 135gXe can be enhanced to give additional discrimination between these Xe isotopes by using the plastic scintillation sample cell as a beta spectrometer to resolve the conversion electron peaks. The automated system will be a key factor in monitoring the Comprehensive Test Ban Treaty.

3He and BF 3 neutron detector pressure effect and model comparison

NASA Astrophysics Data System (ADS)

Lintereur, Azaree; Conlin, Kenneth; Ely, James; Erikson, Luke; Kouzes, Richard; Siciliano, Edward; Stromswold, David; Woodring, Mitchell

2011-10-01

Radiation detection systems for homeland security applications must possess the capability of detecting both gamma rays and neutrons. The radiation portal monitor systems that are currently deployed use a plastic scintillator for detecting gamma rays and 3He gas-filled proportional counters for detecting neutrons. Proportional counters filled with 3He are the preferred neutron detectors for use in radiation portal monitor systems because 3He has a large neutron cross-section, is relatively insensitive to gamma-rays, is neither toxic nor corrosive, can withstand extreme environments, and can be operated at a lower voltage than some of the alternative proportional counters. The amount of 3He required for homeland security and science applications has depleted the world supply and there is no longer enough available to fill the demand. Thus, alternative neutron detectors are being explored. Two possible temporary solutions that could be utilized while a more permanent solution is being identified are reducing the 3He pressure in the proportional counters and using boron trifluoride gas-filled proportional counters. Reducing the amount of 3He required in each of the proportional counters would decrease the rate at which 3He is being used; not enough to solve the shortage, but perhaps enough to increase the amount of time available to find a working replacement. Boron trifluoride is not appropriate for all situations as these detectors are less sensitive than 3He, boron trifluoride gas is corrosive, and a much higher voltage is required than what is used with 3He detectors. Measurements of the neutron detection efficiency of 3He and boron trifluoride as a function of tube pressure were made. The experimental results were also used to validate models of the radiation portal monitor systems.

Real-time {sup 90}Sr Counter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaneko, Naomi; Kawai, Hideyuki; Kodama, Satoshi

2015-07-01

Radioisotopes have been emitted around Japan due to a nuclear accident at the Fukushima Daiichi nuclear power station in March 2011. A problem is the contaminated water including the atomic nucleus which relatively has a long half- life time and soluble such as {sup 90}Sr, {sup 137}Cs. Internal exposures by {sup 90}Sr are more dangerous than {sup 137}Cs's because Sr has effective half-life time of 18 years and property of accumulation in a born. We have developed real-time {sup 90}Sr counter which is sensitive beta-ray of maximum kinematic energy of 2.28 MeV from {sup 90}Sr and insensitive of beta-ray ofmore » maximum kinematic energy of 1.17 MeV and gamma-ray from {sup 90}Sr by Cherenkov detection. This counter composes of Cerenkov counter, trigger scintillation counter and veto counter. Silica aerogel for Cherenkov counter can obtain refractive index between 1.017 and 1.049 easily. And wavelength shifting fiber (WLSF) is used as a light guide for extending effective area and producing lower cost. A mechanism of the identification of {sup 90}Sr is explained in following. In case of {sup 90}Sr, when the trigger counter reacts on the beta-ray from {sup 90}Sr, aerogel emits the Cherenkov light and WLSF reacts and read the Cherenkov light. On the other hand, in case of {sup 137}Cs, the trigger counter reacts on the beta-ray, aerogel stops the beta- ray and Cherenkov light is not emitted. Therefore, aerogel has a function as a radiator and shielding material. the gamma-ray is not reacted on the lower density detector. Cosmic rays would be also reacted by the veto counter. A prototype counter whose the effective area is 30 cm x 10 cm was obtained (2.0±1.2){sup 3} of mis-identification as {sup 137}Cs/{sup 90}Sr. Detection limit in the surface contamination inspection depends on measurement time and effective area mainly. The sensitivity of wide range, 10{sup -2} - 10{sup 4} Bq/cm{sup 2}, is obtained by adjustment of detection level in circuit of this counter. A lower radioactive sample (< 10{sup -2} Bq/cm{sup 2}) allows be detected significantly by heating treatment to evaporate water shielding the beta-rays. (authors)« less

Identification and Quantification of the Water Soluble Components of JP-4 and a Determination of Their Biological Effects upon Selected Freshwater Organisms.

DTIC Science & Technology

1981-11-30

minutes. Absorbances ere read at 630am on a Perkin-Elmer (Coleman 124) double beam speztrophotonater and compared to a standard curve made from para ... aminophenol (PAP), 0.05mg to 0-00oll Q- "lagM.Lnat RfteklpMi4I &&all UndWE 0.5m1 of aninopyrine stock solution (7.0mg/mI buffer) was added to the...on the HPLC column mill be collected and counted in a liq- uid scintillation counter G. Scanning electron microscopy will be used for studying gross

Angular correlations in the prompt neutron emission in spontaneous fission of 252Cf

NASA Astrophysics Data System (ADS)

Kopatch, Yuri; Chietera, Andreina; Stuttgé, Louise; Gönnenwein, Friedrich; Mutterer, Manfred; Gagarski, Alexei; Guseva, Irina; Dorvaux, Olivier; Hanappe, Francis; Hambsch, Franz-Josef

2017-09-01

An experiment aiming at the detailed investigation of angular correlations in the neutron emission from spontaneous fission of 252Cf has been performed at IPHC Strasbourg using the angle-sensitive double ionization chamber CODIS for measuring fission fragments and a set of 60 DEMON scintillator counters for neutron detection. The main aim of the experiment is to search for an anisotropy of neutron emission in the center-of-mass system of the fragments. The present status of the data analysis and the full Monte-Carlo simulation of the experiment are reported in the present paper.

Energy spectrum of medium energy gamma-rays from the galactic center region. [experimental design

NASA Technical Reports Server (NTRS)

Palmeira, R. A. R.; Ramanujarao, K.; Dutra, S. L. G.; Bertsch, D. L.; Kniffen, D. A.; Morris, D. J.

1978-01-01

A balloon-borne magnetic core digitized spark chamber with two assemblies of spark-chambers above and below the scintillation counters was used to measure the medium energy gamma ray flux from the galactic center region. Gamma ray calculations are based on the multiple scattering of the pair electrons in 15 aluminum plates interleaved in the spark chamber modules. Counting rates determined during ascent and at ceiling indicate the presence of diffuse component in this energy range. Preliminary results give an integral flux between 15 and 70 MeV compared to the differential points in other results.

Investigating the Functional Role of Prostate-Specific Membrane Antigen and Its Enzymatic Activity in Prostate Cancer Metastasis

DTIC Science & Technology

2009-11-01

24-well plates and grown for 2-3 days prior to initiating the experiments. Cells were rinsed in Krebs -Ringer buffer, and incubated with mAbs J591...J415, 7E11 at 10µg/ml in Krebs - Ringer buffer at 370C for 30 min. 3H-NAAG were co-incubated along with the respective antibody at 0.8 µci/ml for 60 min...at 370C. Cells were washed in Krebs -Ringer buffer, and lysed in 1N of NaOH. Cell lysates were counted in liquid scintillation counter. PSMA negative

Study of mass flow distribution and chemical composition of comets from solar induced X-ray fluorescence

NASA Technical Reports Server (NTRS)

Gorenstein, P.

1979-01-01

The expected performance of an X-ray detector as an instrument aboard a mission to a comet was evaluated. The functions of the detector are both nondispersive analysis of chemical composition and measurement of mass flow from the comet nucleus. Measurements are to be carried out at a distance from the comet. The approach distances considered are of the order of 1000 km and 100 km. A new type of X-ray detector, a proportional scintillation detector, is considered as an X-ray counter for nondispersive elemental analysis.

REVIEWS OF TOPICAL PROBLEMS: Neutrinos from stellar core collapses: present status of experiments

NASA Astrophysics Data System (ADS)

Ryazhskaya, Ol'ga G.

2006-10-01

The responses of the existing underground detectors to neutrino bursts from collapsing stars evolving in accordance with various models are considered. The interpretation of the results of detecting neutrino radiation from the SN1987A supernova explosion is discussed. A combination of large scintillation counters interlayered with iron slabs (as a target for the electron neutrino interaction) is suggested as a detector for core collapse neutrinos. Bounds for the galactic rate of core collapses based on 28 years of observations by neutrino telescopes of RAS INR, LSD, and LVD detectors are presented.

Construction of 144, 565 keV and 5.0 MeV monoenergetic neutron calibration fields at JAERI.

PubMed

Tanimura, Y; Yoshizawa, M; Saegusa, J; Fujii, K; Shimizu, S; Yoshida, M; Shibata, Y; Uritani, A; Kudo, K

2004-01-01

Monoenergetic neutron calibration fields of 144, 565 keV and 5.0 MeV have been developed at the Facility of Radiation Standards of JAERI using a 4 MV Pelletron accelerator. The 7Li(p,n)7Be and 2H(d,n)3He reactions are employed for neutron production. The neutron energy was measured by the time-of-flight method with a liquid scintillation detector and calculated with the MCNP-ANT code. A long counter is employed as a neutron monitor because of the flat response. The monitor is set up where the influence of inscattered neutrons from devices and their supporting materials at a calibration point is as small as possible. The calibration coefficients from the monitor counts to the neutron fluence at a calibration point were obtained from the reference fluence measured with the transfer instrument of the primary standard laboratory (AIST), a 24.13 cm phi Bonner sphere counter. The traceability of the fields to AIST was established through the calibration.

Four methods for determining the composition of trace radioactive surface contamination of low-radioactivity metal

NASA Astrophysics Data System (ADS)

O'Keeffe, H. M.; Burritt, T. H.; Cleveland, B. T.; Doucas, G.; Gagnon, N.; Jelley, N. A.; Kraus, C.; Lawson, I. T.; Majerus, S.; McGee, S. R.; Myers, A. W.; Poon, A. W. P.; Rielage, K.; Robertson, R. G. H.; Rosten, R. C.; Stonehill, L. C.; VanDevender, B. A.; Van Wechel, T. D.

2011-12-01

Four methods for determining the composition of low-level uranium- and thorium-chain surface contamination are presented. One method is the observation of Cherenkov light production in water. In two additional methods a position-sensitive proportional counter surrounding the surface is used to make both a measurement of the energy spectrum of alpha particle emissions and also coincidence measurements to derive the thorium-chain content based on the presence of short-lived isotopes in that decay chain. The fourth method is a radiochemical technique in which the surface is eluted with a weak acid, the eluate is concentrated, added to liquid scintillator and assayed by recording beta-alpha coincidences. These methods were used to characterize two 'hotspots' on the outer surface of one of the 3He proportional counters in the Neutral Current Detection array of the Sudbury Neutrino Observatory experiment. The methods have similar sensitivities, of order tens of ng, to both thorium- and uranium-chain contamination.

Development of a lithium fluoride zinc sulfide based neutron multiplicity counter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cowles, Christian; Behling, Spencer; Baldez, Phoenix

Past 3He shortages led to investigations into replacement options for neutron detectors in systems that previously used 3He-based technologies. The goal of this research was to investigate the feasibility of a full-scale lithium fluoride with silver activated zinc sulfide (LiF/ZnS) based neutron multiplicity counter. The LiF/ZnS based neutron multiplicity counter (LiNMC) was developed based on an iterative process between modeling and experimental measurements. Each active region of the LiNMC contains five sheets of LiF/ZnS sandwiched between six sheets of wavelength shifting plastic to form neutron detection stacks. The wavelength shifted scintillation light was collected by photomultiplier tubes located on eachmore » end of the stacks. Twelve such detector stacks were placed around a sample chamber in a square arrangement with lithiated high density polyethylene blocks in the corners to reflect high energy neutrons and capture low energy neutrons. Preliminary calibration with a 252Cf neutron source showed that the LiNMC was able to achieve 36% neutron detection efficiency (ε) and an 11.7 μs neutron die-away time (τ) for a doubles Figure-of-merit (ε2/ τ) of 109. This is the highest doubles Figure-of-merit performance measured to-date for a 3He-free neutron multiplicity counter system. By the end of this project, the LiNMC’s basic components were integrated into a single laboratory scale system capable of proof-of-concept measurements.« less

The GlueX Start Counter and Beam Asymmetry$$\\Sigma$$ in Single $$\\pi^{0}$$ Photoproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pooser, Eric

The GlueX experiment aims to study meson photoproduction while utilizing the coherent bremsstrahlung technique to produce a 9 GeV linearly polarized photon beam incident on a liquid H 2 target. A Start Counter detector was fabricated to properly identify the accelerator electron beam buckets and to provide accurate timing information. The Start Counter detector was designed to operate at photon intensities of up to 10 8 γ/s in the coherent peak and provides a timing resolution ~300 ps so as to provide successful identification of the electron beam buckets to within 99% accuracy. Furthermore, the Start Counter detector provides excellent solid angle coverage, ~ 90% of 4π hermeticity, and a high degree of segmentation for background rejection. It consists of a cylindrical array of 30 scintillators with pointed ends that bend towards the beam at the downstream end. Magnetic field insensitive silicon photomultiplier detectors were selected as the readout system. An initial measurement of the beam asymmetry Sigma in the exclusive reaction γmore » $$\\vec{p}$$→ π 0p, where π 0 → γ has been carried out utilizing the GlueX spectrometer during the Spring 2015 commissioning run. The tagged photon energies ranged from 2.5≤ Eγ ≤ 3.0 GeV in the coherent peak. These measurements were then compared to the world data set and show remarkable agreement with only two hours of physics production running.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castillo-Mejia, Fermin; Herrera-Velazquez, J. Julio E.; Gamboa-deBuen, I.

The Fuego Nuevo II (FN-II) dense plasma focus device is a small machine (4.6 kJ), operating at the Instituto de Ciencias Nucleares, UNAM, in which neutrons, as well as soft and hard X rays have been studied with a number of diagnostics. Neutrons are studied with silver activation counters, and scintillator-photomultiplier detectors, while their angular distribution inside and outside the discharge chamber have been studied with CR-39 plastic track detectors. The soft X rays are studied with a multiple-pin-hole camera and PIN diodes, while the hard X-rays are observed with the scintillator-photomultiplier detectors mentioned above. When a needle is insertedmore » on the inner electrode, a bright spot of hard x-rays can be concentrated, and used for the production of high-contrast radiography. Dosimetric measurements have been made for X-rays crossing a 300 micron aluminum window, through the axis of the machine, showing an average dose of 0.11{+-}0.01 mGy per shot. In contrast, the average dose with a hollow cathode is 0.077{+-}0.006 mGy per shot.« less

C$sup 12$(n,p) B$sup 12$ CROSS SECTION FOR 14.9- TO 17.5-MEV NEUTRONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kreger, W.E.; Kern, B.D.

1958-09-23

The cross section for the C/sup 12/(n,p)B/sup 12/ reaction has been measured for 14.9- to 17.5-Mev nuetrons. The neutrons were obtained from the T(d,n)He/sup 4/ reaction and their flux density was determined by counting the recoil alpha particles or by counting the neutrons directly with a Li/sup 6/I(Eu) scintillation counter. A cylindrical plastic scintillator 5 inches in diameter and 3 inches in length served as the carbon-containing target and permitted the counting of the B/sup 12/ decay beta rays in nine consecutive 7-msec intervals during the beam-off period or a pulsed neutron beam cycle. The cross section rises from slightlymore » above the reaction threshold of 13.6-Mev to a value of 29.09 plus or minus 4.36 millibarns at 17.5 Mev. The B/sup 12/ beta decay half life has been redetermined as 18.87 plus or minus 0.50 milliseconds. (auth)« less

FIRST experiment: Fragmentation of Ions Relevant for Space and Therapy

NASA Astrophysics Data System (ADS)

Agodi, C.; Abou-Haidar, Z.; Alvarez, M. A. G.; Aumann, T.; Balestra, F.; Battistoni, G.; Bocci, A.; Bohlen, T. T.; Bondì, M.; Boudard, A.; Brunetti, A.; Carpinelli, M.; Cappuzzello, F.; Cavallaro, M.; Carbone, D.; Cirrone, G. A. P.; Cortes-Giraldo, M. A.; Cuttone, G.; De Napoli, M.; Durante, M.; Fernandez-Garcia, J. P.; Finck, C.; Foti, A.; Gallardo, M. I.; Golosio, B.; Iarocci, E.; Iazzi, F.; Ickert, G.; Introzzi, R.; Juliani, D.; Krimmer, J.; Kurz, N.; Labalme, M.; Lavagno, A.; Leifels, Y.; Le Fevre, A.; Leray, S.; Marchetto, F.; Monaco, V.; Morone, M. C.; Nicolosi, D.; Oliva, P.; Paoloni, A.; Patera, V.; Piersanti, L.; Pleskac, R.; Quesada, J. M.; Randazzo, N.; Romano, F.; Rossi, D.; Rosso, V.; Rousseau, M.; Sacchi, R.; Sala, P.; Sarti, A.; Scheidenberger, C.; Schuy, C.; Sciubba, A.; Sfienti, C.; Simon, H.; Sipala, V.; Spiriti, E.; Stuttge, L.; Tropea, S.; Younis, H.

2013-03-01

Nuclear fragmentation processes are relevant in different fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at SIS accelerator of GSI laboratory in Darmstadt, has been designed for the measurement of different ions fragmentation cross sections at different energies between 100 and 1000 MeV/nucleon. The experiment is performed by an international collaboration made of institutions from Germany, France, Italy and Spain. The experimental apparatus is partly based on an already existing setup made of the ALADIN magnet, the MUSIC IV TPC, the LAND2 neutron detector and the TOFWALL scintillator TOF system, integrated with newly designed detectors in the interaction Region (IR) around the carbon removable target: a scintillator Start Counter, a Beam Monitor drift chamber, a silicon Vertex Detector and a Proton Tagger for detection of light fragments emitted at large angles (KENTROS). The scientific program of the FIRST experiment started on summer 2011 with the study of the 400 MeV/nucleon 12C beam fragmentation on thin (8mm) carbon target.

High-speed photon-counting x-ray computed tomography system utilizing a multipixel photon counter

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Enomoto, Toshiyuki; Watanabe, Manabu; Hitomi, Keitaro; Takahashi, Kiyomi; Sato, Shigehiro; Ogawa, Akiro; Onagawa, Jun

2009-07-01

High-speed photon counting is useful for discriminating photon energy and for decreasing absorbed dose for patients in medical radiography, and the counting is usable for constructing an x-ray computed tomography (CT) system. A photon-counting x-ray CT system is of the first generation type and consists of an x-ray generator, a turn table, a translation stage, a two-stage controller, a multipixel photon counter (MPPC) module, a 1.0-mm-thick LSO crystal (scintillator), a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeating the linear scanning and the rotation of an object, and projection curves of the object are obtained by the linear scanning using the detector consisting of a MPPC module and the LSO. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The lower level of the photon energy is roughly determined by a comparator circuit in the module, and the unit of the level is the photon equivalent (pe). Thus, the average photon energy of the x-ray spectra increases with increasing the lower-level voltage of the comparator. The maximum count rate was approximately 20 Mcps, and energy-discriminated CT was roughly carried out.

Active Interrogation of Depleted Uranium Using a Single Pulse, High-Intensity Photon and Mixed Photon-Neutron Source

NASA Astrophysics Data System (ADS)

Clemett, Ceri D.; Martin, Philip N.; Hill, Cassie; Threadgold, James R.; Maddock, Robert C.; Campbell, Ben; O'Malley, John; Woolf, Richard S.; Phlips, Bernard F.; Hutcheson, Anthony L.; Wulf, Eric A.; Zier, Jacob C.; Jackson, Stuart L.; Commisso, Robert J.; Schumer, Joseph W.

2015-04-01

Active interrogation is a method used to enhance the likelihood of detection of shielded special nuclear material (SNM); an external source of radiation is used to interrogate a target and to stimulate fission within any SNM present. Radiation produced by the fission process can be detected and used to infer the presence of the SNM. The Atomic Weapons Establishment (AWE) and the Naval Research Laboratory (NRL) have carried out a joint experimental study into the use of single pulse, high-intensity sources of bremsstrahlung x-rays and D(γb, n)H photoneutrons in an active interrogation system. The source was operated in both x-ray-only and mixed x-ray/photoneutron modes, and was used to irradiate a depleted uranium (DU) target which was enclosed by up to 150 g·cm - 2 of steel shielding. Resulting radiation signatures were measured by a suite of over 80 detectors and the data used to characterise detectable fission signatures as a function of the areal mass of the shielding. This paper describes the work carried out and discusses data collected with 3He proportional counters, NaI(Tl) scintillators and Eljen EJ-309 liquid scintillators. Results with the x-ray-only source demonstrate detection ( > 3\\sigmab) of the DU target through a minimum of 113 g·cm - 2 of steel, dropping to 85 g·cm- 2 when using a mixed x-ray/photoneutron source. The 3He proportional counters demonstrate detection ( > 3\\sigmab) of the DU target through the maximum 149. 7 g·cm - 2 steel shielding deployed for both photon and mixed x-ray/photoneutron sources.

Time-correlated neutron analysis of a multiplying HEU source

NASA Astrophysics Data System (ADS)

Miller, E. C.; Kalter, J. M.; Lavelle, C. M.; Watson, S. M.; Kinlaw, M. T.; Chichester, D. L.; Noonan, W. A.

2015-06-01

The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated 3He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations.

Characterization of large TSV MPPC arrays (4 × 4 ch and 8 × 8 ch) in scintillation spectrometry

NASA Astrophysics Data System (ADS)

Grodzicka-Kobylka, M.; Szczesniak, T.; Moszyński, M.; Korolczuk, S.; Baszak, J.; Kapusta, M.

2017-10-01

The main objective of this work was to characterize the new multi-pixel photon counter (MPPC) arrays with a 12 × 12mm2 and a 24 × 24mm2 active area, made using through-silicon via (TSV) technology and with trenches introduced between the cells, in gamma-ray spectrometry with five different scintillators: CsI:Tl, NaI:Tl, LSO/LYSO, BGO, and LaBr3. The results of the study are compared to those obtained previously with the older sample of the 12 × 12mm2 MPPC array made as a monolithic device. TSV MPPC array with the size of 24 × 24mm2 is one of the first commercially available SiPM with such a large active area and with the dead space between channels minimized to only 0.2 mm. Moreover, in these devices, Hamamatsu introduced trenches between cells to reduce cross-talk. Hence excess noise factor (ENF) was also reduced from a value of 1.7 to 1.2 in comparison to the "old" monolithic sample (data for the same overvoltage of 1.3V). Whereby for the new MPPCs, the optimum operating voltage is higher by about 0.6V. In consequence, this higher optimal overvoltage means a higher photon detection efficiency (PDE) and number of photoelectrons, and leads to improved energy resolution. Energy resolution measured for the 662keV full energy peak in a 137 Csγ-source spectrum recorded with 12 × 12mm2 TSV MPPC and two CsI:Tl scintillators (12 × 12 × 12mm3 and 1 × 1 in) equals to 5.8% and 6.8%, respectively. For the "old" MPPC with the same CsI:Tl scintillators energy resolution is equal to 6.4% and 7.1%, respectively. These improved TSV MPPC arrays can be commercially used for scintillation light readout of "large" crystals with a diameter of 1 × 1 in or 2 × 2 in, suitable for gamma spectrometry in a wide range of applications. The combination of new 8 × 8 ch (24 × 24mm2) TSV MPPC and 2 × 2 in NaI:Tl gives an excellent energy resolution below 8%, despite the incomplete match of the scintillator surface to the active area of MPPC and loss of the part of the light.

PRESCILA: a new, lightweight neutron rem meter.

PubMed

Olsher, Richard H; Seagraves, David T; Eisele, Shawna L; Bjork, Christopher W; Martinez, William A; Romero, Leonard L; Mallett, Michael W; Duran, Michael A; Hurlbut, Charles R

2004-06-01

Conventional neutron rem meters currently in use are based on 1960's technology that relies on a large neutron moderator assembly surrounding a thermal detector to achieve a rem-like response function over a limited energy range. Such rem meters present an ergonomic challenge, being heavy and bulky, and have caused injuries during radiation protection surveys. Another defect of traditional rem meters is a poor high-energy response above 10 MeV, which makes them unsuitable for applications at high-energy accelerator facilities. Proton Recoil Scintillator-Los Alamos (PRESCILA) was developed as a low-weight (2 kg) alternative capable of extended energy response, high sensitivity, and moderate gamma rejection. An array of ZnS(Ag) based scintillators is located inside and around a Lucite light guide, which couples the scintillation light to a sideview bialkali photomultiplier tube. The use of both fast and thermal scintillators allows the energy response function to be optimized for a wide range of operational spectra. The light guide and the borated polyethylene frame provide moderation for the thermal scintillator element. The scintillators represent greatly improved versions of the Hornyak and Stedman designs from the 1950's, and were developed in collaboration with Eljen Technology. The inherent pulse height advantage of proton recoils over electron tracks in the phosphor grains eliminates the need for pulse shape discrimination and makes it possible to use the PRESCILA probe with standard pulse height discrimination provided by off-the-shelf health physics counters. PRESCILA prototype probes have been extensively tested at both Los Alamos and the German Bureau of Standards, Physikalisch-Technische Bundesanstalt. Test results are presented for energy response, directional dependence, linearity, sensitivity, and gamma rejection. Initial field tests have been conducted at Los Alamos and these results are also given. It is concluded that PRESCILA offers a viable, ergonomically superior, alternative to traditional rem meters that is effective for a wide range of neutron fields. The probe is capable of excellent sensitivity (40 counts per minute per microSv h-1 for 241AmBe) and extended energy response to beyond 20 MeV. Directional response is uniform (+/-15%) over a wide range of energies. Response linearity has been characterized to over 20 mSv h-1. Gamma rejection is effective in gamma fields up to 2 mSv h-1. The PRESCILA technology has been commercialized and is now offered under license by Ludlum Measurements, Inc.

New High Energy Electron Component of Earth Radiation Belt

NASA Astrophysics Data System (ADS)

Dmitrenko, V. V.; Galper, A. M.; Gratchev, V. M.; Kirillov-Ugryumov, V. G.; Ulin, S. E.; Voronov, S. A.

The Earth Radiation Belt (ERB) was discovered in the course of the first flights of Russian and American satellites with conventional instruments (gas discharge and scintillation counters), which made it possible to investigate many characteristics of trapped particles and simulate adequate radiation belt models. However, the experimental and theoretical evidence accumulated over recent time, needs more elaborate measurements for its interpretation. These measurements became feasible after the development of devices based on more perfect detectors (solid and gas-filled Cherenkov detectors, magnetic spectrometer, scintillation time-of-flight systems). The evidence requiring new direct measurements in the ERB was obtained in the late 1960s in the course of balloon flights carried out by Cosmophysics Laboratory of the Moscow Engineering and Physics Institute. In these flights a correlation between the high energy electron flux in the upper atmosphere and perturbations ofthe Earth's magnetosphere was established. This phenomenon could be explained assuming there exist high energy electron fluxes in the ERB. High energy electron fluxes in the ERB were recorded for the first time in the direct experiments carried out on board orbital station 'Salyut-6' (orbit altitude - 350 km, inclination 51.6 deg). A scintillation-Cherenkov telescope 'Elena' controlled by cosmonauts was preset to different programmed positions. The measurements were made in the periphery of the ERB, namely, in the part which goes as low as several hundred km in the Brazil Anomaly Region (BRA). The flux of electrons with energies above 30 MeV was up to 104 (m2s sr)-1.

Real time spectrometer for thermal neutrons from radiotherapic accelerators

NASA Astrophysics Data System (ADS)

Mozzanica, A.; Bartesaghi, G.; Bolognini, D.; Conti, V.; Mascagna, V.; Prest, M.; Scazzi, S.; Cappelletti, P.; Frigerio, M.; Gelosa, S.; Monti, A.; Ostinelli, A.; Bevilacqua, R.; Giannini, G.; Totaro, P.; Vallazza, E.

2007-10-01

Radiotherapy accelerators can produce high energy photon beams for deep tumour treatments. Photons with energies greater than 8 MeV produce neutrons via photoproduction. The PHONES (PHOto NEutron Source) project is developing a neutron moderator to use the photoproduced neutrons for BNCT (Boron Neutron Capture Therapy) in hospital environments. In this framework we are developing a real time spectrometer for thermal neutrons exploiting the bunch structure of the beam. Since the beam is produced by a linear accelerator, in fact, particles are sent to the patient in bunches with a rate of 150-300 Hz depending on the beam type and energy. The neutron spectrum is usually measured with integrating detectors such as bubble dosimeters or TLDs, which integrate over a time interval and an energy one. We are developing a scintillator detector to measure the neutron spectrum in real time in the interval between bunches, that is in the thermal region. The signals from the scintillator are discriminated and sampled by a dedicated clock in a Cyclone II FPGA by Altera, thus obtaining the neutron time of flight spectrum. The exploited physical process in ordinary plastic scintillators is neutron capture by H with a subsequent γ emission. The measured TOF spectrum has been compared with a BF 3 counter one. A dedicated simulation with MCNP is being developed to extract the energy spectrum from the TOF one. The paper will present the results of the prototype measurements and the status of the simulation.

Performance of ionospheric maps in support of long baseline GNSS kinematic positioning at low latitudes

NASA Astrophysics Data System (ADS)

Park, J.; Sreeja, V.; Aquino, M.; Cesaroni, C.; Spogli, L.; Dodson, A.; De Franceschi, G.

2016-05-01

Ionospheric scintillation occurs mainly at high and low latitude regions of the Earth and may impose serious degradation on GNSS (Global Navigation Satellite System) functionality. The Brazilian territory sits on one of the most affected areas of the globe, where the ionosphere behaves very unpredictably, with strong scintillation frequently occurring in the local postsunset hours. The correlation between scintillation occurrence and sharp variations in the ionospheric total electron content (TEC) in Brazil is demonstrated in Spogli et al. (2013). The compounded effect of these associated ionospheric disturbances on long baseline GNSS kinematic positioning is studied in this paper, in particular when ionospheric maps are used to aid the positioning solution. The experiments have been conducted using data from GNSS reference stations in Brazil. The use of a regional TEC map generated under the CALIBRA (Countering GNSS high-Accuracy applications Limitations due to Ionospheric disturbances in BRAzil) project, referred to as CALIBRA TEC map (CTM), was compared to the use of the Global Ionosphere Map (GIM), provided by the International GNSS Service (IGS). Results show that the use of the CTM greatly improves the kinematic positioning solution as compared with that using the GIM, especially under disturbed ionospheric conditions. Additionally, different hypotheses were tested regarding the precision of the TEC values obtained from ionospheric maps, and its effect on the long baseline kinematic solution evaluated. Finally, this study compares two interpolation methods for ionospheric maps, namely, the Inverse Distance Weight and the Natural Neighbor.

Towards monolithic scintillator based TOF-PET systems: practical methods for detector calibration and operation.

PubMed

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

2016-07-07

Gamma-ray detectors based on thick monolithic scintillator crystals can achieve spatial resolutions  <2 mm full-width-at-half-maximum (FWHM) and coincidence resolving times (CRTs) better than 200 ps FWHM. Moreover, they provide high sensitivity and depth-of-interaction (DOI) information. While these are excellent characteristics for clinical time-of-flight (TOF) positron emission tomography (PET), the application of monolithic scintillators has so far been hampered by the lengthy and complex procedures needed for position- and time-of-interaction estimation. Here, the algorithms previously developed in our group are revised to make the calibration and operation of a large number of monolithic scintillator detectors in a TOF-PET system practical. In particular, the k-nearest neighbor (k-NN) classification method for x,y-position estimation is accelerated with an algorithm that quickly preselects only the most useful reference events, reducing the computation time for position estimation by a factor of ~200 compared to the previously published k-NN 1D method. Also, the procedures for estimating the DOI and time of interaction are revised to enable full detector calibration by means of fan-beam or flood irradiations only. Moreover, a new technique is presented to allow the use of events in which some of the photosensor pixel values and/or timestamps are missing (e.g. due to dead time), so as to further increase system sensitivity. The accelerated methods were tested on a monolithic scintillator detector specifically developed for clinical PET applications, consisting of a 32 mm  ×  32 mm  ×  22 mm LYSO : Ce crystal coupled to a digital photon counter (DPC) array. This resulted in a spatial resolution of 1.7 mm FWHM, an average DOI resolution of 3.7 mm FWHM, and a CRT of 214 ps. Moreover, the possibility of using events missing the information of up to 16 out of 64 photosensor pixels is shown. This results in only a small deterioration of the detector performance.

Advanced Multilayer Composite Heavy-Oxide Scintillator Detectors for High Efficiency Fast Neutron Detection

NASA Astrophysics Data System (ADS)

Ryzhikov, Vladimir D.; Naydenov, Sergei V.; Pochet, Thierry; Onyshchenko, Gennadiy M.; Piven, Leonid A.; Smith, Craig F.

2018-01-01

We have developed and evaluated a new approach to fast neutron and neutron-gamma detection based on large-area multilayer composite heterogeneous detection media consisting of dispersed granules of small-crystalline scintillators contained in a transparent organic (plastic) matrix. Layers of the composite material are alternated with layers of transparent plastic scintillator material serving as light guides. The resulting detection medium - designated as ZEBRA - serves as both an active neutron converter and a detection scintillator which is designed to detect both neutrons and gamma-quanta. The composite layers of the ZEBRA detector consist of small heavy-oxide scintillators in the form of granules of crystalline BGO, GSO, ZWO, PWO and other materials. We have produced and tested the ZEBRA detector of sizes 100x100x41 mm and greater, and determined that they have very high efficiency of fast neutron detection (up to 49% or greater), comparable to that which can be achieved by large sized heavy-oxide single crystals of about Ø40x80 cm3 volume. We have also studied the sensitivity variation to fast neutron detection by using different types of multilayer ZEBRA detectors of 100 cm2 surface area and 41 mm thickness (with a detector weight of about 1 kg) and found it to be comparable to the sensitivity of a 3He-detector representing a total cross-section of about 2000 cm2 (with a weight of detector, including its plastic moderator, of about 120 kg). The measured count rate in response to a fast neutron source of 252Cf at 2 m for the ZEBRA-GSO detector of size 100x100x41 mm3 was 2.84 cps/ng, and this count rate can be doubled by increasing the detector height (and area) up to 200x100 mm2. In summary, the ZEBRA detectors represent a new type of high efficiency and low cost solid-state neutron detector that can be used for stationary neutron/gamma portals. They may represent an interesting alternative to expensive, bulky gas counters based on 3He or 10B neutron detection technologies.

Relativistic astrophysics. [design analysis and performance tests of Cerenkov counters for detection of iron isotopes

NASA Technical Reports Server (NTRS)

Price, P. B.

1976-01-01

The design, experimental testing, and calibration (error analysis) of a high resolution Cerenkov-scintillation detector is presented. The detector is capable of detecting iron isotopes and heavy ions of cosmic rays, and of performing direct measurements of individual neighboring isotopes at charge resolution 26. It utilizes Lexan (trademark) sheets, and has been used in flight packages of balloons and on the Skylab. The detector will be able to provide more information on violet astrophysical processes, such as thermonuclear reactions on neutron stars. Ground support and display equipment which are to be used in conjunction with the detector are also discussed.

A study of aging effects of barrel Time-Of-Flight system in the BESIII experiment

NASA Astrophysics Data System (ADS)

Liu, Huan-Huan; Sun, Sheng-Sen; Fang, Shuang-Shi; Wu, Zhi; Dai, Hong-Liang; Heng, Yue-Kun; Zhou, Ming; Deng, Zi-Yan; Liu, Huai-Min

2018-02-01

The Time-Of-Flight system consisting of plastic scintillation counters plays an important role for particle identification in the BESIII experiment at the BEPCII double ring e+e- collider. Degradation of the detection efficiency of the barrel TOF system has been observed since the start of physical data taking and this effect has triggered intensive and systematic studies about aging effects of the detector. The aging rates of the attenuation lengths and relative gains are obtained based on the data acquired in past several years. This study is essential for ensuring an extended operation of the barrel TOF system in optimal conditions.

Method for rapid screening analysis of Sr-90 in edible plant samples collected near Fukushima, Japan.

PubMed

Amano, Hikaru; Sakamoto, Hideaki; Shiga, Norikatsu; Suzuki, Kaori

2016-06-01

A screening method for measuring (90)Sr in edible plant samples by focusing on (90)Y in equilibrium with (90)Sr is reported. (90)Y was extracted from samples with acid, co-precipitated with iron hydroxide, and precipitated with oxalic acid. The dissolved oxalate precipitate was loaded on an extraction chromatography resin, and the (90)Y-enriched eluate was analyzed by Cherenkov counting with a TDCR liquid scintillation counter. (90)Sr ((90)Y) concentration was determined in plant samples collected near the damaged Fukushima Daiichi Nuclear Power Plants with this method. Copyright © 2016 Elsevier Ltd. All rights reserved.

A balloon-borne ionization spectrometer with very large aperture for the detection of high energy cosmic rays

NASA Technical Reports Server (NTRS)

Atallah, K.; Modlinger, A.; Schmidt, W. K. H.; Cleghorn, T. F.

1975-01-01

A balloon experiment which was used to determine the chemical composition of very high-energy cosmic rays up to and beyond 100 GeV/nucleon is described. The detector had a geometric factor of 1 sq m sr and a total weight on the balloon of 2100 kg. The apparatus consisted of an ionization spectrometer, spark chambers, and plastic scintillation and Cherenkov counters. It was calibrated at CERN up to 24 GeV/c protons and at DESY up to 7 GeV/c electrons. In October 1972 it was flown successfully on a stratospheric balloon.

An enzymic radiochemical method for determining phosphatidylglycerol in amniotic fluid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siegel, L.; Walker, S.I.; Robin, N.I.

We describe an enzymic quantification of phosphatidylglycerol in amniotic fluid. Phosphatidylglycerol is hydrolyzed in alkali and the resulting glycerol is then enzymatically phosphorylated with adenosine 5'-(gamma-/sup 32/P)triphosphate to yield glycero(/sup 32/P)phosphate. After removal of excess (gamma-/sup 32/P)ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. Triglyceride in the amniotic fluid is hydrolyzed by lipase before extraction and thus does not interfere with the analysis. This method is specific for phosphatidylglycerol. Preliminary studies suggest that a phosphatidylglycerol value greater than or equal to 10 nmol/mL correlates with fetal lung maturity.

A compact and high efficiency GAGG well counter for radiocesium concentration measurements

NASA Astrophysics Data System (ADS)

Yamamoto, Seiichi; Ogata, Yoshimune

2014-07-01

After the Fukushima nuclear disaster, social concern about radiocesium (137Cs and 134Cs) contamination in food increased. However, highly efficient instruments that can measure low level radioactivity are quite expensive and heavy. A compact, lightweight, and reliable radiation detector that can inexpensively monitor low level radiocesium is highly desired. We developed a compact and highly efficient radiocesium detector to detect ~32 keV X-rays from radiocesium instead of high energy gamma photons. A 1-mm thick GAGG scintillator was selected to effectively detect ~32 keV X-rays from 137Cs to reduce the influence of ambient radiation. Four sets of 25 mm×25 mm×1 mm GAGG plates, each of which was optically coupled to a triangular-shaped light guide, were optically coupled to a photomultiplier tube (PMT) to form a square-shaped well counter. Another GAGG plate was directly optically coupled to the PMT to form its bottom detector. The energy resolution of the GAGG well counter was 22.3% FWHM for 122 keV gamma rays and 32% FWHM for ~32 keV X-rays. The counting efficiency for the X-rays from radiocesium (mixture of 137Cs and 134Cs) was 4.5%. In measurements of the low level radiocesium mixture, a photo-peak of ~32 keV X-rays can clearly be distinguished from the background. The minimum detectable activity (MDA) was estimated to be ~100 Bq/kg for 1000 s measurement. The results show that our developed GAGG well counter is promising for the detection of radiocesium in food.

Use of CLYC spectrometer in counter-terrorism applications

NASA Astrophysics Data System (ADS)

Ing, H.; Smith, M. B.; Koslowsky, M. R.; Andrews, H. R.

2015-05-01

A new scintillator crystal, now known as CLYC (Cs2LiYCl6:Ce), has been under development for over 15 years (1). It was primarily of interest for radiation detection applications because of its good energy resolution for gamma rays (< 4% for 662 keV gamma rays) and its capability for detection of thermal neutrons. The pulse shapes of the signals from the two radiations are different, which allow them to be separated electronically, permitting simultaneous detection of gamma rays and neutrons. The crystal is now commercially available. Early investigations of the neutron response by the current authors (2) revealed that CLYC also responds to fast neutrons. In fact, the good energy resolution of the response under monoenergetic neutron irradiations showed that CLYC was an excellent high-energy neutron spectrometer. This discovery has great impact on the field of neutron spectroscopy, which has numerous, although often specialized, applications. This presentation focuses on applications in counter-terrorism scenarios where neutrons may be involved. The relative importance of the fast neutron response of CLYC, compared to the thermal and gamma-ray response, will be discussed for these scenarios.

Real-time X-ray Diffraction: Applications to Materials Characterization

NASA Technical Reports Server (NTRS)

Rosemeier, R. G.

1984-01-01

With the high speed growth of materials it becomes necessary to develop measuring systems which also have the capabilities of characterizing these materials at high speeds. One of the conventional techniques of characterizing materials was X-ray diffraction. Film, which is the oldest method of recording the X-ray diffraction phenomenon, is not quite adequate in most circumstances to record fast changing events. Even though conventional proportional counters and scintillation counters can provide the speed necessary to record these changing events, they lack the ability to provide image information which may be important in some types of experiment or production arrangements. A selected number of novel applications of using X-ray diffraction to characterize materials in real-time are discussed. Also, device characteristics of some X-ray intensifiers useful in instantaneous X-ray diffraction applications briefly presented. Real-time X-ray diffraction experiments with the incorporation of image X-ray intensification add a new dimension in the characterization of materials. The uses of real-time image intensification in laboratory and production arrangements are quite unlimited and their application depends more upon the ingenuity of the scientist or engineer.

15Mcps photon-counting X-ray computed tomography system using a ZnO-MPPC detector and its application to gadolinium imaging.

PubMed

Sato, Eiichi; Sugimura, Shigeaki; Endo, Haruyuki; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Osawa, Akihiro; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2012-01-01

15Mcps photon-counting X-ray computed tomography (CT) system is a first-generation type and consists of an X-ray generator, a turntable, a translation stage, a two-stage controller, a detector consisting of a 2mm-thick zinc-oxide (ZnO) single-crystal scintillator and an MPPC (multipixel photon counter) module, a counter card (CC), and a personal computer (PC). High-speed photon counting was carried out using the detector in the X-ray CT system. The maximum count rate was 15Mcps (mega counts per second) at a tube voltage of 100kV and a tube current of 1.95mA. Tomography is accomplished by repeated translations and rotations of an object, and projection curves of the object are obtained by the translation. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The minimum exposure time for obtaining a tomogram was 15min, and photon-counting CT was accomplished using gadolinium-based contrast media. Copyright © 2011 Elsevier Ltd. All rights reserved.

Implementation of the TDCR liquid scintillation method at CNEA-LMR, Argentina.

PubMed

Arenillas, Pablo; Cassette, Philippe

2006-01-01

During the last two years, a triple-to-double coincidence ratio (TDCR) system was assembled and adjusted at the CNEA-LMR, Argentina. The new counting system will add complementary capabilities to the absolute measurements section of the CNEA-LMR. This work describes its implementation and validation. Several checks and a set of beta-emitting standard solutions were used in order to perform the validation experiments. In preliminary measurements, a 3H LNHB solution with reference activity concentration of (119.7+/-0.9) kBq/g on 11 November 2003 was used. The CNEA-LMR TDCR counter gave, at the same reference date, an activity concentration of (120+/-1) kBq/g. Results and improvements are presented in detail. Concerning the asymmetry of the system, the quantum efficiency of the three photomultiplier tubes was studied for different operating conditions of the focusing voltage. The counter also includes an automatic system to change the efficiency by defocusing the photomultipliers and on the other hand, it was coupled to a HPGe detector to also measure beta-gamma coincidences.

Tests of the MICE Electron Muon Ranger frontend electronics with a small scale prototype

NASA Astrophysics Data System (ADS)

Bolognini, D.; Bene, P.; Blondel, A.; Cadoux, F.; Debieux, S.; Giannini, G.; Graulich, J. S.; Lietti, D.; Masciocchi, F.; Prest, M.; Rothenfusser, K.; Vallazza, E.; Wisting, H.

2011-08-01

The MICE experiment is being commissioned at RAL to demonstrate the feasibility of the muon ionization cooling technique for future applications such as the Neutrino Factory and the Muon Collider. The cooling will be evaluated by measuring the emittance before and after the cooling channel with two 4 T spectrometers; to distinguish muons from the background, a multi-detector particle identification system is foreseen: three Time of Flight stations, two Cherenkov counters and a calorimetric system consisting of a pre-shower layer and a fully active scintillator detector (EMR) are used to discriminate muons from pions and electrons. EMR consists of 48 planes of triangular scintillating bars coupled to WLS fibers readout by single PMTs on one side and MAPMTs on the other; each plane sensible area is 1 m 2. This article deals with a small scale prototype of the EMR detector which has been used to test the MAPMT frontend electronics based on the MAROC ASIC; the tests with cosmic rays using both an analog mode and a digital readout mode are presented. A very preliminary study on the cross talk problem is also shown.

First measurements of muon production rate using a novel pion capture system at MuSIC

NASA Astrophysics Data System (ADS)

Cook, S.; D'Arcy, R.; Fukuda, M.; Hatanaka, K.; Hino, Y.; Kuno, Y.; Lancaster, M.; Mori, Y.; Nam, T. H.; Ogitsu, T.; Sakamoto, H.; Sato, A.; Truong, N. M.; Yamamoto, A.; Yoshida, M.; Wing, M.

2013-02-01

The MuSIC (Muon Science Innovative Channel) beam line at RCNP (Research Centre for Nuclear Physics), Osaka will be the most intense source of muons in the world. A proton beam is incident on a target and, by using a novel capture solenoid, guides the produced pions into the beam line where they subsequently decay to muons. This increased muon flux will allow more precise measurements of cLFV (charged Lepton Flavour Violation) as well as making muon beams more economically feasible. Currently the first 36° of solenoid beam pipe have been completed and installed for testing with low proton current of 1 nA. Measurements of the total particle flux and the muon life time were made. The measurements were taken using thin plastic scintillators coupled to MPPCs (Multi-Pixel Photon Counter) that surrounded a magnesium or copper stopping target. The scintillators were used to record which particles stopped and their subsequent decay times giving a muon yield of 8.5 × 105 muons W-1proton beam or 3 × 108 muons s-1 when using the RCNP's full power (400 W).

RADIOLOGICAL PHYSICS DIVISION SEMIANNUAL REPORT FOR JULY THROUGH DECEMBER 1958

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1959-05-01

ABS>Progress is reported in the following studies: the decay time of irradiated scintillation solutions; the performance of twin scintillation detectors for measuring neutrons in the presence of gamma radiation; the measurement of cosmic ray neutron background with a twin scintillation fast neutron spectrometer; the diffusion and absorption of gases in plastic-walled ionization chambers; calculations of the drift velocity and the energy distribution of electrons of helium, neon, argon, and nitrogen under the action of a uniform electric field; the development of equipment for tracer studies of atmospheric diffusion; the deposition and retention of isotopes of actinium, radon, radium, and thoriummore » in bone; the effects of age on calcium metabolism in bone,; the development of a mathematical theory of the retention of radioactive elements by bone; the development of a reproducible method for directly determining individual alpha activities in mixtures; the design of a flow-gas Geiger counter; a survey of the natural radioactivity of a number of municipal water supplies; measurements of activity in individuals by means of the human spectrometer; measurements of the cesium-l37 content of human subjects; measurements of the atmospheric content of cesium-137 as a function of time; a comparison of background radioactivity at the Laboratory and a site approximately 250 feet below grade level; development of a spectrometric method for measurements of radioactivity in soil; the effects of meteorological variables on the distribution of radon in the atmosphere; and studies of atmospheric diffusion. A list of publications during the period is included. (For preceding period see ANL-5919.) (C.H.)« less

Measurement of absolute gamma emission probabilities

NASA Astrophysics Data System (ADS)

Sumithrarachchi, Chandana S.; Rengan, Krish; Griffin, Henry C.

2003-06-01

The energies and emission probabilities (intensities) of gamma-rays emitted in radioactive decays of particular nuclides are the most important characteristics by which to quantify mixtures of radionuclides. Often, quantification is limited by uncertainties in measured intensities. A technique was developed to reduce these uncertainties. The method involves obtaining a pure sample of a nuclide using radiochemical techniques, and using appropriate fractions for beta and gamma measurements. The beta emission rates were measured using a liquid scintillation counter, and the gamma emission rates were measured with a high-purity germanium detector. Results were combined to obtain absolute gamma emission probabilities. All sources of uncertainties greater than 0.1% were examined. The method was tested with 38Cl and 88Rb.

DAQ for commissioning and calibration of a multichannel analyzer of scintillation counters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tortorici, F.; Jones, M.; Bellini, V.

We report the status of the Data Acquisition (DAQ) system for the Coordinate Detector (CDET) module of the Super Bigbite Spectrometer facility at Hall A of Thomas Jefferson Accelerator Facility. Presently, the DAQ is fully assembled and tested with one CDET module. The commissioning of CDET module, that is the goal of the tests presented here, consists essentially in the measures of the amplitude and time-over-threshold of signals from cosmic rays. Hardware checks, the developing of DAQ control and off-line analysis software are ongoing; the module currently seems to work roughly accordingly to expectations. Data presented in this note aremore » still preliminary.« less

11-year cycle solar modulation of cosmic ray intensity inferred from C-14 content variation in dated tree rings

NASA Technical Reports Server (NTRS)

Fan, C. Y.; Chen, T. M.; Yun, S. X.; Dai, K. M.

1983-01-01

A liquid scintillation-photomultiplier tube counter system was used to measure the Delta-C-14 values of 60 tree rings, dating from 1866 to 1925, that were taken from a white spruce grown in Canada at 68 deg N, 130 deg W. A 10-percent variation is found which is anticorrelated with sunspot numbers, although the amplitude of the variation is 2-3 times higher than expected in trees grown at lower latitudes. A large dip in the data at about 1875 suggests an anomalously large modulation of cosmic ray intensity during the 1867-1878 AD solar cycle, which was the most active of the 19th century.

High-Precision Half-Life Measurements for the Superallowed Fermi β+ Emitters 14O and 18Ne

NASA Astrophysics Data System (ADS)

Laffoley, A. T.; Andreoiu, C.; Austin, R. A. E.; Ball, G. C.; Bender, P. C.; Bidaman, H.; Bildstein, V.; Blank, B.; Bouzomita, H.; Cross, D. S.; Deng, G.; Diaz Varela, A.; Dunlop, M. R.; Dunlop, R.; Finlay, P.; Garnsworthy, A. B.; Garrett, P.; Giovinazzo, J.; Grinyer, G. F.; Grinyer, J.; Hadinia, B.; Jamieson, D. S.; Jigmeddorj, B.; Ketelhut, S.; Kisliuk, D.; Leach, K. G.; Leslie, J. R.; MacLean, A.; Miller, D.; Mills, B.; Moukaddam, M.; Radich, A. J.; Rajabali, M. M.; Rand, E. T.; Svensson, C. E.; Tardiff, E.; Thomas, J. C.; Turko, J.; Voss, P.; Unsworth, C.

High-precision half-life measurements, at the level of ±0.04%, for the superallowed Fermi emitters 14O and 18Ne have been performed at TRIUMF's Isotope Separator and Accelerator facility. Using 3 independent detector systems, a gas-proportional counter, a fast plastic scintillator, and a high-purity germanium array, a series of direct β and γ counting measurements were performed for each of the isotopes. In the case of 14O, these measurements were made to help resolve an existing discrepancy between detection methods, whereas for 18Ne the half-life precision has been improved in anticipation of forthcoming high-precision branching ratio measurements.

Neutral Kaon Spectrometer 2

NASA Astrophysics Data System (ADS)

Kaneta, M.; Beckford, B.; Fujii, T.; Fujii, Y.; Futatsukawa, K.; Han, Y. C.; Hashimoto, O.; Hirose, K.; Ishikawa, T.; Kanda, H.; Kimura, C.; Maeda, K.; Nakamura, S. N.; Suzuki, K.; Tsukada, K.; Yamamoto, F.; Yamazaki, H.

2018-04-01

A large-acceptance spectrometer, Neutral Kaon Spectrometer 2 (NKS2), was newly constructed to explore various photoproduction reactions in the gigaelectronvolt region at the Laboratory of Nuclear Science (LNS, currently ELPH), Tohoku University. The spectrometer consisted of a dipole magnet, drift chambers, and plastic scintillation counters. NKS2 was designed to separate pions and protons in a momentum range of less than 1 GeV/ c, and was placed in a tagged photon beamline. A cryogenic H2/D2 target fitted to the spectrometer were designed. The design and performance of the detectors are described. The results of the NKS2 experiment on analyzing strangeness photoproduction data using a 0.8-1.1 GeV tagged photon beam are also presented.

Rapid Method for the Radioisotopic Analysis of Gaseous End Products of Anaerobic Metabolism

PubMed Central

Nelson, David R.; Zeikus, J. G.

1974-01-01

A gas chromatographic procedure for the simultaneous analysis of 14C-labeled and unlabeled metabolic gases from microbial methanogenic systems is described. H2, CH4, and CO2 were separated within 2.5 min on a Carbosieve B column and were detected by thermal conductivity. Detector effluents were channeled into a gas proportional counter for measurement of radioactivity. This method was more rapid, sensitive, and convenient than gas chromatography-liquid scintillation techniques. The gas chromatography-gas proportional counting procedure was used to characterize the microbial decomposition of organic matter in anaerobic lake sediments and to monitor 14CH4 formation from H2 and 14CO2 by Methanosarcina barkeri. PMID:4854029

SU-F-J-182: Investigation of Systems for Improved Accuracy in Clinical Y-90 Percent Delivered Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

McBeth, R; Elder, D; Kesner, A

2016-06-15

Purpose: Y-90 Selective Internal Radiation Therapy (SIRT) is used to treat liver tumors, and by nature has variability in the percent of the intended dose that is actually delivered. To determine the quality of the administration, pre and post activity measurements are taken, and used to infer percent delivered. Vendor specifications indicate the use of an ion chamber to take these measurements. In our work, we investigated the accuracy of ion chambers, and compared them to other detector systems. Methods: We have built phantoms, phantom holders, and protocols, which allow us to measure our Y90 doses with varying apparatuses: amore » dose calibrator, a Geiger-counter, an ion chamber, a crystal based thyroid probe, and a gamma camera. We have set up a system that has enabled us to gather data by measuring clinical Y90 doses as they are used in the clinic using all of the instrumental methods. Five initial doses (25 measurements/acquisitions) have been taken at the time of this abstract submission. Results: Our initial results show that measurements acquired using scintillation based detectors (thyroid probe and gamma camera) correlate better with the gold standard (i.e. the dose calibrator). Pearson correlations between the dose calibrator measurements and the GM counter, Ion chamber, thyroid probe, and gamma camera were found to be 0.88, 0.83, 0.98, 0.99, respectively. More acquisitions and analysis are planned to determine the precision of the systems, as well as optimal energy window settings. Conclusion: It is likely that current standard practice can be improved using scintillation crystal based detectors. Such systems are more sensitive, can integrate signal, and can use energy discrimination. Furthermore, phantoms can be built to integrate with probe and gamma camera systems that are robust and provide reproducibility. Future work will include expanded acquisition and analysis.« less

Broad Energy Range Neutron Spectroscopy using a Liquid Scintillator and a Proportional Counter: Application to a Neutron Spectrum Similar to that from an Improvised Nuclear Device

PubMed Central

Randers-Pehrson, Gerhard; Marino, Stephen A.; Garty, Guy; Harken, Andrew; Brenner, David J.

2015-01-01

A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n)3He and D(d,n)3He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the 9Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima. PMID:26273118

Broad Energy Range Neutron Spectroscopy using a Liquid Scintillator and a Proportional Counter: Application to a Neutron Spectrum Similar to that from an Improvised Nuclear Device.

PubMed

Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A; Garty, Guy; Harken, Andrew; Brenner, David J

2015-09-11

A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n) 3 He and D(d,n) 3 He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the 9 Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima.

Investigation of Deuterium Loaded Materials Subject to X-Ray Exposure

NASA Technical Reports Server (NTRS)

Benyo, Theresa L.; Steinetz, Bruce M.; Hendricks, Robert C.; Martin, Richard E.; Forsley, Lawrence P.; Daniels, Christopher C.; Chait, Arnon; Pines, Vladimir; Pines, Marianna; Penney, Nicholas;

Simultaneous determination of gross alpha, gross beta and ²²⁶Ra in natural water by liquid scintillation counting.

PubMed

Fons, J; Zapata-García, D; Tent, J; Llauradó, M

2013-11-01

The determination of gross alpha, gross beta and (226)Ra activity in natural waters is useful in a wide range of environmental studies. Furthermore, gross alpha and gross beta parameters are included in international legislation on the quality of drinking water [Council Directive 98/83/EC]. In this work, a low-background liquid scintillation counter (Wallac, Quantulus 1220) was used to simultaneously determine gross alpha, gross beta and (226)Ra activity in natural water samples. Sample preparation involved evaporation to remove (222)Rn and its short-lived decay daughters. The evaporation process concentrated the sample ten-fold. Afterwards, a sample aliquot of 8 mL was mixed with 12 mL of Ultima Gold AB scintillation cocktail in low-diffusion vials. In this study, a theoretical mathematical model based on secular equilibrium conditions between (226)Ra and its short-lived decay daughters is presented. The proposed model makes it possible to determine (226)Ra activity from two measurements. These measurements also allow determining gross alpha and gross beta simultaneously. To validate the proposed model, spiked samples with different activity levels for each parameter were analysed. Additionally, to evaluate the model's applicability in natural water, eight natural water samples from different parts of Spain were analysed. The eight natural water samples were also characterised by alpha spectrometry for the naturally occurring isotopes of uranium ((234)U, (235)U and (238)U), radium ((224)Ra and (226)Ra), (210)Po and (232)Th. The results for gross alpha and (226)Ra activity were compared with alpha spectrometry characterization, and an acceptable concordance was obtained. Copyright © 2013 Elsevier Ltd. All rights reserved.

California GAMA Special Study. Development of a Capability for the Analysis of Krypton-85 in Groundwater Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Visser, Ate; Bibby, Richard K.; Moran, Jean E.

A capability for the analysis of krypton-85 ( 85Kr) in groundwater samples was developed at LLNL. Samples are collected by extracting gas from 2000-4000 L of groundwater at the well, yielding approximately 0.2 cm 3 STP krypton. Sample collection takes 1 to 4 hours. Krypton is purified in the laboratory using a combination of molecular sieve and activated charcoal traps, and transferred to a liquid scintillation vial. The 85Kr activity is measured by liquid scintillation on a Quantulus 1220 liquid scintillation counter from PerkinElmer. The detection limit for a typical 0.2 cm 3Kr sample size is 11% of the presentmore » day activity in air, corresponding to the decay corrected activity in air in 1987. The typical measurement uncertainty is below 10% for recently recharged samples. Six groundwater samples were collected, purified and counted. 85Kr was not detected in any of the samples counted at LLNL. 85Kr was detected by the low level counting laboratory of Bern University in all samples between 1.5 and 6.6 decays per minute per cm 3 krypton, corresponding to decay corrected activities in air between 1971 and 1985. The new capability is an excellent complement to tritium-helium, expanding the existing suite of age dating tools available to the GAMA program ( 35S, 3H/ 3He, 14C and radiogenic helium). 85Kr can replace 3H/ 3He in settings where 3H/ 3He ages are impossible to determine (for example where terrigenic helium overwhelms tritiogenic helium) and provides additional insight into travel time distributions in complex mixed groundwater systems.« less

Detection of absorption lines in the spectra of X-ray bursts from X1608-52

NASA Astrophysics Data System (ADS)

Nakamura, Norio; Inoue, Hajime; Tanaka, Yasuo

X-ray bursts from X 1608-52 were observed with the gas scintillation proportional counters on the Tenma satellite. Absorption features were detected in the spectra of three bursts among 17 bursts observed. These absorption features are consistent with a common absorption line at 4.1 keV. The energy and the properties of the absorption lines of the X 1608-52 bursts are very similar to those observed from the X 1636-53 bursts by Waki et al. (1984). Near equality of the absorption-line energies for X 1636-53 and X 1608-52 would imply that mass and radius of the neutron stars in these two systems are very similar to each other.

The T2K ND280 off-axis pi-zero detector

NASA Astrophysics Data System (ADS)

Assylbekov, S.; Barr, G.; Berger, B. E.; Berns, H.; Beznosko, D.; Bodek, A.; Bradford, R.; Buchanan, N.; Budd, H.; Caffari, Y.; Connolly, K.; Danko, I.; Das, R.; Davis, S.; Day, M.; Dytman, S.; Dziomba, M.; Flight, R.; Forbush, D.; Gilje, K.; Hansen, D.; Hignight, J.; Imber, J.; Johnson, R. A.; Jung, C. K.; Kravtsov, V.; Le, P. T.; Lopez, G. D.; Malafis, C. J.; Manly, S.; Marino, A. D.; McFarland, K. S.; McGrew, C.; Metelko, C.; Nagashima, G.; Naples, D.; Nicholls, T. C.; Nielsen, B.; Paolone, V.; Paul, P.; Pearce, G. F.; Qian, W.; Ramos, K.; Reinherz-Aronis, E.; Rodrigues, P. A.; Ruterbories, D.; Schmidt, J.; Schwehr, J.; Siyad, M.; Steffens, J.; Tadepalli, A. S.; Taylor, I. J.; Thorpe, M.; Toki, W.; Vanek, C.; Warner, D.; Weber, A.; Wilkes, R. J.; Wilson, R. J.; Yanagisawa, C.; Yuan, T.

2012-09-01

The pi-zero detector (PØD) is one of the subdetectors that makes up the off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino experiment. The primary goal for the PØD is to measure the relevant cross-sections for neutrino interactions that generate π0's, especially the cross-section for neutral current π0 interactions, which are one of the dominant sources of background to the νμ→νe appearance signal in T2K. The PØD is composed of layers of plastic scintillator alternating with water bags and brass sheets or lead sheets and is one of the first detectors to use Multi-Pixel Photon Counters (MPPCs) on a large scale.

Highlights from the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Sagawa, H.

2014-10-01

The Telescope Array (TA) is the largest experiment in the Northern Hemisphere currently studying the origin and nature of ultra-high-energy cosmic rays above ˜1018 eV by measuring their energy spectrum, mass composition, and arrival directions. It is located in the western desert of central Utah, USA. The TA detector consists of a surface array of 507 scintillation counters, deployed on a square grid of 1.2-km spacing that covers approximately 700 km2, and 38 fluorescence telescopes located at three sites looking over the surface array. The TA commenced hybrid observation with both sets of detectors in 2008. Here, we present recent results from these 5 years of data and outline our ongoing and near future plans.

Hodoscope readout system

DOEpatents

Lee, L.Y.

1973-12-01

A readout system has been provided for reading out a radiation multidetector device with a reduced number of signal sensors. A radiation hodoscope, such as an array of scintillation counters, multiwire proportional counter array, or a set of multidetectors which do not receive signals simultaneously, is divided into equal numbered groups. A first group of signal terminals is connected to the equal numbered groups of detectors so that a signal from any one of the detectors of a group will be fed to one of the first group of terminals. A second group of signal terminals is connected to the detector groups so that a signal from a particular numbered detector of each of the detector groups is connected to one of the second group of terminals. Both groups of signal terminals are, in turn, coupled to signal sensors so that when a signal is simultaneously observed in one of the first group of terminals and one of the second group of tenniinals the specific detector detecting a radiation event is determined. The sensors are arranged in such a manner that a binary code is developed from their outputs which can be stored in a digital storage means according to the location of the event in the multidetector device. (Official Gazette)

Mcps-range photon-counting x-ray computed tomography system

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Enomoto, Toshiyuki; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-10-01

10 Mcps photon counting was carried out using a detector consisting of a 2.0 mm-thick ZnO (zinc oxide) single-crystal scintillator and an MPPC (multipixel photon counter) module in an X-ray computed tomography (CT) system. The maximum count rate was 10 Mcps (mega counts per second) at a tube voltage of 70 kV and a tube current of 2.0 mA. Next, a photon-counting X-ray CT system consists of an X-ray generator, a turntable, a scan stage, a two-stage controller, the ZnO-MPPC detector, a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan with a scan velocity of 25 mm/s. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The exposure time for obtaining a tomogram was 600 s at a scan step of 0.5 mm and a rotation step of 1.0°, and photon-counting CT was accomplished using iodine-based contrast media.

The High Energy Particle Detector on Board of the China Seismo-Electromagnetic Satellite

NASA Astrophysics Data System (ADS)

Sparvoli, Roberta; Palma, Francesco; Panico, Beatrice; Sotgiu, Alessandro; Vitale, Vincenzo

2016-08-01

The study of the Van Allen belts temporal stability is among the main objectives of the China Seismo- Electromagnetic Satellite (CSES) space mission, as well as the study of other electromagnetic disturbances with possible seismic origin. In parallel to this, the CSES mission will address issues of heliospheric and magnetospheric physics, by measuring the cosmic radiation around the Earth.The CSES satellite, developed by a Chinese-Italian collaboration, will be launched in the first half of 2017 and inserted into a circular Sun-synchronous orbit with 98° inclination and 500 km altitude. The expected lifetime is 5 years. CSES hosts several instruments on board: 2 magnetometers, an electric field detector, a plasma analyser, a Langmuir probe and a High-Energy Particle Detector (HEPD). The HEPD detector, responsibility of the Italian side of the CSES collaboration, will measure electrons (3 - 100 MeV) and protons (30 - 300 MeV) along CSES orbit. It consists of a segmented layer of plastic scintillators for the trigger and a calorimeter constituted by a tower of plastic scintillator counters and a LYSO plane. The direction of the incident particle is provided by two planes of double-side silicon micro-strip detectors placed in front of the trigger. Topic of this talk is the technical description of the HEPD and its main characteristics.

Performance of coincidence-based PSD on LiF/ZnS Detectors for Multiplicity Counting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, Sean M.; Stave, Sean C.; Lintereur, Azaree

Abstract: Mass accountancy measurement is a nuclear nonproliferation application which utilizes coincidence and multiplicity counters to verify special nuclear material declarations. With a well-designed and efficient detector system, several relevant parameters of the material can be verified simultaneously. 6LiF/ZnS scintillating sheets may be used for this purpose due to a combination of high efficiency and short die-away times in systems designed with this material, but involve choices of detector geometry and exact material composition (e.g., the addition of Ni-quenching in the material) that must be optimized for the application. Multiplicity counting for verification of declared nuclear fuel mass involves neutronmore » detection in conditions where several neutrons arrive in a short time window, with confounding gamma rays. This paper considers coincidence-based Pulse-Shape Discrimination (PSD) techniques developed to work under conditions of high pileup, and the performance of these algorithms with different detection materials. Simulated and real data from modern LiF/ZnS scintillator systems are evaluated with these techniques and the relationship between the performance under pileup and material characteristics (e.g., neutron peak width and total light collection efficiency) are determined, to allow for an optimal choice of detector and material.« less

First results of experiments with a medical one-coordinate X-ray detector on synchrotron radiation of VEPP-4

NASA Astrophysics Data System (ADS)

Dementyev, E. N.; Dovga, E. Ya.; Kulipanov, G. N.; Medvedko, A. S.; Mezentsev, N. A.; Pindyurin, V. F.; Sheromov, M. A.; Skrinsky, A. N.; Sokolov, A. S.; Ushakov, V. A.; Zagorodnikov, E. I.; Kaidorin, A. G.; Neugodov, Yu. V.

1986-05-01

The first results of studying the performance of a fast X-ray one-coordinate detector on the SR beam from VEPP-4 are presented. The detector consists of 128 independent channels, each being a scintillation counter on the basis of NaI(Tl) crystals. The spatial resolution of the detector constitutes 1.5 mm and its speed of response is 128 × 1 MHz. The main purpose of the detector is to examine the human circulatory system by the method of difference angiography at an energy of quanta corresponding to the K-absorption edge of iodine (33.2 keV). The first results on radiation exposure of the blood vessels of a live dog with a spatial resolution of 0.75 mm are given.

Basic instrumentation for Hall A at Jefferson Lab

NASA Astrophysics Data System (ADS)

Alcorn, J.; Anderson, B. D.; Aniol, K. A.; Annand, J. R. M.; Auerbach, L.; Arrington, J.; Averett, T.; Baker, F. T.; Baylac, M.; Beise, E. J.; Berthot, J.; Bertin, P. Y.; Bertozzi, W.; Bimbot, L.; Black, T.; Boeglin, W. U.; Boykin, D. V.; Brash, E. J.; Breton, V.; Breuer, H.; Brindza, P.; Brown, D.; Burtin, E.; Calarco, J. R.; Cardman, L. S.; Carr, R.; Cates, G. D.; Cavata, C.; Chai, Z.; Chang, C. C.; Chant, N. S.; Chen, J.-P.; Choi, S.; Chudakov, E.; Churchwell, S.; Coman, M.; Cisbani, E.; Colilli, S.; Colombel, N.; Crateri, R.; Dale, D. S.; Degrande, N.; de Jager, C. W.; De Leo, R.; Deur, A.; Dezern, G.; Diederich, B.; Dieterich, S.; di Salvo, R.; Djawotho, P.; Domingo, J.; Ducret, J.-E.; Dutta, D.; Egiyan, K.; Epstein, M. B.; Escoffier, S.; Esp, S.; Ewell, L. A.; Finn, J. M.; Fissum, K. G.; Folts, E.; Fonvieille, H.; Frois, B.; Frullani, S.; Gao, H.; Gao, J.; Garibaldi, F.; Gasparian, A.; Gavalya, A.; Gayou, O.; Gilad, S.; Gilman, R.; Giuliani, F.; Glamazdin, A.; Glashausser, C.; Gomez, J.; Gorbenko, V.; Gorringe, T.; Gricia, M.; Griffioen, K.; Hamilton, D.; Hansen, J.-O.; Hersman, F. W.; Higinbotham, D. W.; Holmes, R.; Holmgren, H.; Holtrop, M.; d'Hose, N.; Hovhannisyan, E.; Howell, C.; Huber, G. M.; Hughes, E.; Hyde-Wright, C. E.; Ibrahim, H.; Incerti, S.; Iodice, M.; Iommi, R.; Ireland, D.; Jaminion, S.; Jardillier, J.; Jensen, S.; Jiang, X.; Jones, C. E.; Jones, M. K.; Joo, K.; Jutier, C.; Kahl, W.; Kato, S.; Katramatou, A. T.; Kelly, J. J.; Kerhoas, S.; Ketikyan, A.; Khandaker, M.; Khayat, M.; Kino, K.; Kominis, I.; Korsch, W.; Kox, S.; Kramer, K.; Kumar, K. S.; Kumbartzki, G.; Kuss, M.; Lagamba, L.; Laveissière, G.; Leone, A.; LeRose, J. J.; Marie, F.; Levchuk, L.; Leuschner, M.; Lhuillier, D.; Liang, M.; Livingston, K.; Lindgren, R. A.; Liyanage, N.; Lolos, G. J.; Lourie, R. W.; Lucentini, M.; Madey, R.; Maeda, K.; Malov, S.; Manley, D. M.; Margaziotis, D. J.; Markowitz, P.; Marroncle, J.; Martine, J.; Mayilyan, S.; McCarthy, J. S.; McCormick, K.; Mclntyre, J.; McKeown, R. D.; Meekins, D.; van der Meer, R. L. J.; Meziani, Z.-E.; Michaels, R.; Milbrath, B.; Miller, J. A.; Miller, W.; Mitchell, J.; Mougey, J.; Nanda, S.; Nathan, A.; Neyret, D.; Offermann, E. A. J. M.; Papandreou, Z.; Perdrisat, C. F.; Perrino, R.; Petratos, G. G.; Petrosyan, A.; Pierangeli, L.; Platchkov, S.; Pomatsalyuk, R.; Pripstein, D.; Prout, D. L.; Punjabi, V. A.; Pussieux, T.; Quéméner, G.; Ransomez, R. D.; Ravel, O.; Reitz, B.; Roblin, Y.; Roche, R.; Roedelbronn, M.; Rondon-Aramayo, O. A.; Roos, P. G.; Rosner, G.; Rowntree, D.; Rutledge, G. A.; Rutt, P. M.; Rvachev, M.; Sabatavenere, F.; Saha, A.; Saito, T.; Santavenere, F.; Sarty, A. J.; Schneider, W. J.; Segal, J. P.; Serdarevic-Offermann, A.; Shahinyan, A.; Slifer, K.; Smith, T. P.; Soldi, A.; Sorokin, P.; Souder, P.; Spiegel, S. L.; Stevens, M. A.; Strauch, S.; Suleiman, R.; Templon, J. A.; Terasawa, T.; Todor, L.; Tsubota, H.; Ueno, H.; Ulmer, P. E.; Urciuoli, G. M.; Van Hoorebeke, L.; Van de Vyver, R.; van Verst, S.; Vernin, P.; Vlahovic, B.; Voskanyan, H.; Voutier, E.; Walter, R.; Watson, J. W.; Watts, D. P.; Weinstein, L. B.; Wijesooriya, K.; Wojtsekhowski, B.; Xiang, H.; Xiong, F.; Xu, W.; Zainea, D. G.; Zeps, V.; Zhao, J.; Zheng, X.; Zhou, Z.-L.; Zhu, L.; Zolnierczuk, P. A.

2004-04-01

The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro- and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2×10 -4. A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10 38 cm-2 s-1. The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium.

Accidental neutron dosimetry with human hair

NASA Astrophysics Data System (ADS)

Ekendahl, Daniela; Bečková, Věra; Zdychová, Vlasta; Bulánek, Boris; Prouza, Zdeněk; Štefánik, Milan

2014-11-01

Human hair contains sulfur, which can be activated by fast neutrons. The 32S(n,p)32P reaction with a threshold of 2.5 MeV was used for fast neutron dose estimation. It is a very important parameter for individual dose reconstruction with regards to the heterogeneity of the neutron transfer to the human body. Samples of human hair were irradiated in a radial channel of a training reactor VR-1. 32P activity in hair was measured both, directly by means of a proportional counter, and as ash dispersed in a liquid scintillator. Based on neutron spectrum estimation, a relationship between the neutron dose and induced activity was derived. The experiment verified the practical feasibility of this dosimetry method in cases of criticality accidents or malevolent acts with nuclear materials.

Results from the USIP_UH contribution to the BARREL-4 campaign

NASA Astrophysics Data System (ADS)

Behrend, C. C.; Bering, E. A., III; Ehteshami, A.; Fenton, A.; Gamblin, R.; Greer, M.; Mathur, S.; Glennie, C. L.; Velasquez, B.; Marpaung, J.; Lalata, M. C.

2016-12-01

The Undergraduate Student Instrumentation Project (USIP) at the University of Houston sent a team to Kiruna, Sweden to participate with NASA/Dartmouth's BARREL-4 campaign in August 2016. BARREL-4's primary instrument is an MeV x-ray scintillation counter. The team has provided two different experiments to be flown, a dual frequency GPS receiver to calculate total electron content and a Very Low Frequency (VLF) receiver to measure the VLF emissions associated with electron precipitation. TEC is calculated via finding pseudo-ranges comparing the sent and received signals from passing satellites. The VLF receiver has an air-core magnetic loop antenna that utilizes a transformer coupled with an integrating pre-amp which is then recorded to a standard music recorder. The presentation will include a summary of observations.

The University of Chicago cosmic ray electrons and nuclei experiment on the H spacecraft

NASA Technical Reports Server (NTRS)

Meyer, P.; Evenson, P.

1978-01-01

The University of Chicago instrument on the Heliocentric spacecraft (MEH experiment) will measure the energy spectrum of cosmic electrons in the range 5-400 MeV. In addition, the energy spectra and relative abundances of nuclei from protons to the iron group, with energies ranging from 30 MeV/n to 15 GeV/n, will be determined. Primary scientific objectives involve the study of the long and short term variability of these components as a probe of the structure of the heliosphere. Particles are identified by multiparameter analysis using the pulse height analyzed signals from eight active detectors - silicon solid state, plastic and crystal scintillators are solid and gas Cerenkov counters. Data return is optimized by a three level priority logic scheme.

Thermal neutron radiative capture on cadmium as a counting technique at the INES beam line at ISIS: A preliminary investigation of detector cross-talk.

PubMed

Festa, G; Grazzi, F; Pietropaolo, A; Scherillo, A; Schooneveld, E M

2017-12-01

Experimental tests are presented that assess the cross-talk level among three scintillation detectors used as neutron counters exploiting the thermal neutron radiative capture on Cd. The measurements were done at the INES diffractometer operating at the ISIS spallation neutron source (Rutherford Appleton Laboratory, UK). These tests follow a preliminary set of measurements performed on the same instrument to study the effectiveness of this thermal neutron counting strategy in neutron diffraction measurements, typically performed on INES using squashed 3 He filled gas tubes. The experimental data were collected in two different geometrical configurations of the detectors and compared to results of Monte Carlo simulations, performed using the MCNP code. Copyright © 2017 Elsevier Ltd. All rights reserved.

An automated LS(β)- NaI(Tl)(γ) coincidence system as absolute standard for radioactivity measurements.

PubMed

Joseph, Leena; Das, A P; Ravindra, Anuradha; Kulkarni, D B; Kulkarni, M S

2018-07-01

4πβ-γ coincidence method is a powerful and widely used method to determine the absolute activity concentration of radioactive solutions. A new automated liquid scintillator based coincidence system has been designed, developed, tested and established as absolute standard for radioactivity measurements. The automation is achieved using PLC (programmable logic controller) and SCADA (supervisory control and data acquisition). Radioactive solution of 60 Co was standardized to compare the performance of the automated system with proportional counter based absolute standard maintained in the laboratory. The activity concentrations determined using these two systems were in very good agreement; the new automated system can be used for absolute measurement of activity concentration of radioactive solutions. Copyright © 2018. Published by Elsevier Ltd.

LaCl3:Ce Coincidence Signatures to Calibrate Gamma-ray Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

McIntyre, Justin I.; Schrom, Brian T.; Cooper, Matthew W.

Abstract Calibrating the gamma-ray detection efficiency of radiation detectors in a field environment is difficult under most circumstances. To counter this problem we have developed a technique that uses a Cerium doped Lanthanum-Tri-Chloride (LaCl3:Ce) scintillation detector to provide gated gammas[ , ]. Exploiting the inherent radioactivity of the LaCl3:Ce due to the long-lived radioactive isotope 138La (t1/2 = 1.06 x 1011 yrs) allows the use of the 788 and 1436-keV gammas as a measure of efficiency. In this paper we explore the effectiveness of using the beta-gamma coincidences radiation LaCl3:Ce detector to calibrate the energy and efficiency of a numbermore » of gamma-ray detectors.« less

COSMIC RAYS AND COSMIC SPACE (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vernova, S.N.

1960-08-01

An account is given of recent studies of cosmic rays utilizing both earthbound stations and artificial earth satellites. Phenomena recently uncovered by sputniks are described. A description is given of the cosmic ray laboratory of Moscow University. A particle possessing an energy of l0/sup 15/ ev was detected and the equipment and procedure by which this was done are described. mu mesons in a particle shower produced by cosmic rays were detected at a depth of thirty meters underground. The apparatus required in the sputriks for the study of cosmic rays outside the earth's atmosphere is discussed. The equipment inmore » the sputniks launched to date was transistorized; scintillation counters were used to determine particle energies. A description is given of the large burst of radiation detected by the second sputnik on Nov. 7, 1957. This burst was observed only at latitudes of about 50 to 70 degrees north latitude. The third sputnik had a scintillation counter of high sensitivity which detected relatively weak fluxes of electrons. This equipment fixed the location of the high intensity radiation belt around the earth. A typical graph of count rate and energy current versus geographic location is given. Data are given that indicate the coincidence of peak radiation intensities with those regions where the aurora borealis is seen. The radiation belt extends up to approximately 60,000 km from the earth's surface and is bounded by the magnetic lines of force that intersect the earth' s surface at geomagnetic latitudes of 55 deg and 70 deg . The earth's magnetic field traps these particles and holds them in an orbit that follows magnetic lines of force and oscillates from the northern to the southern hemisphere for long periods of time. A diagram is given of the trajectory of the first Soviet cosmic rocket and changes in radiation intensity along this trajectory are indicated. A maximum radiation intensity was detected at a distance of 20,000 km from the earth's surface. A diagram compares the data of the first and second Soviet cosmic rockets. It is indicated that radiation intensity in the outer belt varies with time due to variation of emanations from the sun. The energy spectrum of radiation in the outer belt was obtained with gas discharge and scintillation counters installed behind varying amounts of lead, copper, and aluminum shielding. Results are given in a diagram of particle and energy flux versus distance from the earth. The conclusion is reached that the outer radiation belt consists of electrons whose energies vary over six orders of magnitude. However the data from the second rocket indicated that the upper limit of electron energies appears to be 5 Mev. The electron flux is highest at an energy of about 1 Mev. It is pointed out that in the outer radiation belt the energy density of radiation approaches its maximum possible value, that is, the energy density of the earth's magnetic field at that distance. A discussion is given of the inner radiation belt, first described by Van Allen. No evidence of radiation belts about the moon was found. A discussion of the possible origins of the outer radiation belt of the earth and of other radiation belts and magnetic fields in space is given. In the study of solar flares, 1500 radiosonde balloon flights were made during the IGY. These flights established that solar flares are an extreme hazard for space travelers. (TTT)« less

Exploring the Cigala/calibra Network Data Base for Ionosphere Monitoring Over Brazil

NASA Astrophysics Data System (ADS)

Vani, B. C.; Galera Monico, J. F.; Shimabukuro, M. H.; Pereira, V. A.; Aquino, M. H.

2013-12-01

The ionosphere in Brazil is strongly influenced by the equatorial anomaly, therefore GNSS based applications are widely affected by ionospheric disturbances. A network for continuous monitoring of the ionosphere has been deployed over its territory since February/2011, as part of the CIGALA and CALIBRA projects. Through CIGALA (Concept for Ionospheric Scintillation Mitigation for Professional GNSS in Latin America), which was funded by European Commission (EC) in the framework of the FP7-GALILEO-2009-GSA (European GNSS Agency), the first stations were deployed at Presidente Prudente, São Paulo state, in February 2011. CIGALA was finalized in February 2012 with eight stations distributed over the Brazilian territory. Through CALIBRA (Countering GNSS high Accuracy applications Limitations due to Ionospheric disturbances in BRAzil), which is also funded by the European Commission now in the framework of the FP7-GALILEO-2011-GSA, new stations are being deployed. Some of the stations are being specifically placed according to geomagnetic considerations aiming to support the development of a local scintillation and TEC model. CALIBRA started in November 2012 and will have two years of duration, focusing on the development of improved and new algorithms that can be applied to high accuracy GNSS techniques in order to tackle the effects of ionospheric disturbances. PolarRxS-PRO receivers, manufactured by Septentrio, have been deployed at all stations This multi-GNSS receiver can collect data at rates of up to 100 Hz, providing ionospheric TEC, scintillation parameters like S4 and Sigma-Phi, and other signal metrics like locktime for all satellites and frequencies tracked. All collected data (raw and ionosphere monitoring records) is stored at a central facility located at the Faculdade de Ciências e Tecnologia da Universidade Estadual Paulista (FCT/UNESP) in Presidente Prudente. To deal with the large amount of data, an analysis infrastructure has also been established in the form of a web based software named ISMR Query Tool, which provides a capability to identify specific behaviors of ionospheric activity through data visualization and data mining. Its web availability and user-specified features allow the users to interact with the data through a simple internet connection, enabling to obtain insight about the ionosphere according with their own previous knowledge. Information about the network, the projects and the tool can be found at the FCT/UNESP Ionosphere web portal available at http://is-cigala-calibra.fct.unesp.br/. This contribution will provide an overview of results extracted using the monitoring and analysis infrastructure, explaining the possibilities offered by the ISMR Query Tool to support analysis of the ionosphere as well as the development of models and mitigation techniques to counter the effects of ionospheric disturbances on GNSS.

6 Mcps photon-counting X-ray computed tomography system using a 25 mm/s-scan linear LSO-MPPC detector and its application to gadolinium imaging

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-12-01

6 Mcps photon counting was carried out using a detector consisting of a 1.0 mm-thick LSO [Lu 2(SiO 4)O] single-crystal scintillator and an MPPC (multipixel photon counter) module in an X-ray computed tomography (CT) system. The maximum count rate was 6 Mcps (mega counts per second) at a tube voltage of 100 kV and a tube current of 0.91 mA. Next, a photon-counting X-ray CT system consists of an X-ray generator, a turntable, a scan stage, a two-stage controller, the LSO-MPPC detector, a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan with a scan velocity of 25 mm/s. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The exposure time for obtaining a tomogram was 600 s at a scan step of 0.5 mm and a rotation step of 1.0°, and photon-counting CT was accomplished using gadolinium-based contrast media.

Mcps-range photon-counting X-ray computed tomography system utilizing an oscillating linear-YAP(Ce) photon detector

NASA Astrophysics Data System (ADS)

Oda, Yasuyuki; Sato, Eiichi; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Osawa, Akihiro; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-07-01

High-speed X-ray photon counting is useful for discriminating photon energy, and the counting can be used for constructing an X-ray computed tomography (CT) system. A photon-counting X-ray CT system consists of an X-ray generator, a turntable, an oscillation linear detector, a two-stage controller, a multipixel photon counter (MPPC) module, a 1.0 mm-thick crystal (scintillator) of YAP(Ce) (cerium-doped yttrium aluminum perovskite), a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeating the linear scanning and the rotation of an object, and projection curves of the object are obtained by the linear scanning using the detector consisting of an MPPC module, the YAP(Ce), and a scan stage. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. Because the lower level of the photon energy was roughly determined by a comparator in the module, the average photon energy of the X-ray spectra increased with increase in the lower-level voltage of the comparator at a constant tube voltage. The maximum count rate was approximately 3 Mcps (mega counts per second), and photon-counting CT was carried out.

Development of a 6LiF/ZnS-based Neutron Multiplicity Counter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stave, Sean C.; Behling, Richard S.; Bernacki, Bruce E.

2016-10-06

Abstract–Neutron multiplicity counters are used in safeguards to provide rapid assay of samples which contain an unknown amount of plutonium in a potentially unknown configuration. A project at PNNL is using regular and nickel-quenched 6LiF/ZnS neutron-scintillator sheets and wavelength shifting plastic for light pipes in place of 3He. A combination of laboratory and modeling work predicts a LiF/ZnS-based system to be able to match or exceed the performance of the best 3He-based systems available. Also, the Ni-quenched material is expected to allow for improved neutron/gamma-ray discrimination at twice the event rate relative to the non-Ni-quenched LiF/ZnS. A new system basedmore » on the LiF/ZnS material is under construction and components are being used to optimize the detection efficiency and neutron/gamma-ray discrimination properties. Components of the new system are partially constructed and undergoing performance testing utilizing high-speed digitizers with field programmable gate arrays to perform the neutron/gamma-ray discrimination. The expected performance of the full-scale system is expected to be nearly the same as for 3He-based systems and is due for completion in 2016.« less

X-Ray Astronomy Research at the Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Austin, Robert A.

1999-01-01

For at least twenty years, NASA's Marshall Space Flight Center (MSFC) has played a major role in the development of X-ray astronomy in the United States. MSFC scientists and engineers are currently involved in a wide range of programs which will contribute to the growth of X-ray astronomy well into the next century. Areas of activity include calibration of X-ray astronomy instrumentation using Marshall's world-class X-ray Calibration Facility (XRCF), development of high-throughput, replicated X-ray optics, X-ray detector development, balloon-based X-ray astronomy, and analysis of Active Galactic Nuclei (AGNs) and clusters of galaxies. Recent milestones include the successful calibration of NASA's premier X-ray Astronomy Satellite - AXAF (recently renamed Chandra), a balloon flight of a large area (1000 sq cm) micro-strip proportional counter, and work on a hard X-ray (30-100 keV) telescope called HERO, capable of high quality spectroscopy and imaging through the use of grazing incidence optics and an Imaging Gas Scintillation Proportional Counter (IGSPC). In my presentation, I will provide a general overview of our research and facilities. I will conclude with a more detailed discussion of our High Energy Replicated Optics (HERO) program and plans for long duration (>100 days) balloon flights which will take place in the near future.

Development of a Scintillation Proximity Assay (SPA) Based, High Throughput Screening Feasible Method for the Identification of PDE12 Activity Modulators.

PubMed

Mang, Samuel; Bucher, Hannes; Nickolaus, Peter

2016-01-01

The scintillation proximity assay (SPA) technology has been widely used to establish high throughput screens (HTS) for a range of targets in the pharmaceutical industry. PDE12 (aka. 2'- phosphodiesterase) has been published to participate in the degradation of oligoadenylates that are involved in the establishment of an antiviral state via the activation of ribonuclease L (RNAse-L). Degradation of oligoadenylates by PDE12 terminates these antiviral activities, leading to decreased resistance of cells for a variety of viral pathogens. Therefore inhibitors of PDE12 are discussed as antiviral therapy. Here we describe the use of the yttrium silicate SPA bead technology to assess inhibitory activity of compounds against PDE12 in a homogeneous, robust HTS feasible assay using tritiated adenosine-P-adenylate ([3H]ApA) as substrate. We found that the used [3H]ApA educt, was not able to bind to SPA beads, whereas the product [3H]AMP, as known before, was able to bind to SPA beads. This enables the measurement of PDE12 activity on [3H]ApA as a substrate using a wallac microbeta counter. This method describes a robust and high throughput capable format in terms of specificity, commonly used compound solvents, ease of detection and assay matrices. The method could facilitate the search for PDE12 inhibitors as antiviral compounds.

KASCADE-Grande measurements of energy spectra for elemental groups of cosmic rays

NASA Astrophysics Data System (ADS)

Apel, W. D.; Arteaga-Velázquez, J. C.; Bekk, K.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Cantoni, E.; Chiavassa, A.; Cossavella, F.; Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Engler, J.; Finger, M.; Fuchs, B.; Fuhrmann, D.; Gils, H. J.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Huber, D.; Huege, T.; Kampert, K.-H.; Kang, D.; Klages, H. O.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Mayer, H. J.; Melissas, M.; Milke, J.; Mitrica, B.; Morello, C.; Oehlschläger, J.; Ostapchenko, S.; Palmieri, N.; Petcu, M.; Pierog, T.; Rebel, H.; Roth, M.; Schieler, H.; Schoo, S.; Schröder, F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Ulrich, H.; Weindl, A.; Wochele, J.; Wommer, M.; Zabierowski, J.

2013-07-01

The KASCADE-Grande air shower experiment [1] consists of, among others, a large scintillator array for measurements of charged particles, N, and of an array of shielded scintillation counters used for muon counting, Nμ. KASCADE-Grande is optimized for cosmic ray measurements in the energy range 10 PeV to about 2000 PeV, where exploring the composition is of fundamental importance for understanding the transition from galactic to extragalactic origin of cosmic rays. Following earlier studies of the all-particle and the elemental spectra reconstructed in the knee energy range from KASCADE data [2], we have now extended these measurements to beyond 200 PeV. By analysing the two-dimensional shower size spectrum N vs. Nμ for nearly vertical events, we reconstruct the energy spectra of different mass groups by means of unfolding methods over an energy range where the detector is fully efficient. The procedure and its results, which are derived based on the hadronic interaction model QGSJET-II-02 and which yield a strong indication for a dominance of heavy mass groups in the covered energy range and for a knee-like structure in the iron spectrum at around 80 PeV, are presented. This confirms and further refines the results obtained by other analyses of KASCADE-Grande data, which already gave evidence for a knee-like structure in the heavy component of cosmic rays at about 80 PeV [3].

Photon counting detector for the personal radiography inspection system "SIBSCAN"

NASA Astrophysics Data System (ADS)

Babichev, E. A.; Baru, S. E.; Grigoriev, D. N.; Leonov, V. V.; Oleynikov, V. P.; Porosev, V. V.; Savinov, G. A.

2017-02-01

X-ray detectors operating in the energy integrating mode are successfully used in many different applications. Nevertheless the direct photon counting detectors, having the superior parameters in comparison with the integrating ones, are rarely used yet. One of the reasons for this is the low value of the electrical signal generated by a detected photon. Silicon photomultiplier (SiPM) based scintillation counters have a high detection efficiency, high electronic gain and compact dimensions. This makes them a very attractive candidate to replace routinely used detectors in many fields. More than 10 years ago the digital scanning radiography system based on multistrip ionization chamber (MIC) was suggested at Budker Institute of Nuclear Physics. The detector demonstrates excellent radiation resistance and parameter stability after 5 year operations and an imaging of up to 1000 persons per day. Currently, the installations operate at several Russian airports and at subway stations in some cities. At the present time we design a new detector operating in the photon counting mode, having superior parameters than the gas one, based on scintillator - SiPM assemblies. This detector has close to zero noise, higher quantum efficiency and a count rate capability of more than 5 MHz per channel (20% losses), which leads to better image quality and improved detection capability. The suggested detector technology could be expanded to medical applications.

A 32 mm  ×  32 mm  ×  22 mm monolithic LYSO:Ce detector with dual-sided digital photon counter readout for ultrahigh-performance TOF-PET and TOF-PET/MRI

NASA Astrophysics Data System (ADS)

Borghi, Giacomo; Peet, Bart Jan; Tabacchini, Valerio; Schaart, Dennis R.

2016-07-01

New applications for positron emission tomography (PET) and combined PET/magnetic resonance imaging (MRI) are currently emerging, for example in the fields of neurological, breast, and pediatric imaging. Such applications require improved image quality, reduced dose, shorter scanning times, and more precise quantification. This can be achieved by means of dedicated scanners based on ultrahigh-performance detectors, which should provide excellent spatial resolution, precise depth-of-interaction (DOI) estimation, outstanding time-of-flight (TOF) capability, and high detection efficiency. Here, we introduce such an ultrahigh-performance TOF/DOI PET detector, based on a 32 mm  ×  32 mm  ×  22 mm monolithic LYSO:Ce crystal. The 32 mm  ×  32 mm front and back faces of the crystal are coupled to a digital photon counter (DPC) array, in so-called dual-sided readout (DSR) configuration. The fully digital detector offers a spatial resolution of ~1.1 mm full width at half maximum (FWHM)/~1.2 mm mean absolute error, together with a DOI resolution of ~2.4 mm FWHM, an energy resolution of 10.2% FWHM, and a coincidence resolving time of 147 ps FWHM. The time resolution closely approaches the best results (135 ps FWHM) obtained to date with small crystals made from the same material coupled to the same DPC arrays, illustrating the excellent correction for optical and electronic transit time spreads that can be achieved in monolithic scintillators using maximum-likelihood techniques for estimating the time of interaction. The performance barely degrades for events with missing data (up to 6 out of 32 DPC dies missing), permitting the use of almost all events registered under realistic acquisition conditions. Moreover, the calibration procedures and computational methods used for position and time estimation follow recently made improvements that make them fast and practical, opening up realistic perspectives for using DSR monolithic scintillator detectors in TOF-PET and TOF-PET/MRI systems.

A new tritium monitor design based on plasma source ion implantation technique

NASA Astrophysics Data System (ADS)

Nassar, Rafat Mohammad

Tritium is an important isotope of hydrogen. The availability of tritium in our environment is manifest through both natural and artificial sources. Consequently, the requirement for tritium handling and usage will continue to increase in the future. An important future contributor is nuclear fusion power plants and facilities. Essential safety regulations and procedures require effective monitoring and measurements of tritium concentrations in workplaces. The unique characteristics of tritium impose an important role on the criteria for its detection and measurement. As tritium decays by the emission of soft beta particles, maximum 18 keV, it cannot be readily detected by commonly used detectors. Specially built monitors are required. Additional complications occur due to the presence of other radioactive isotopes or ambient radiation fields and because of the high diffusivity of tritium. When it is in oxidized form it is 25000 times more hazardous biologically than when in elemental form. Therefore, contamination of the monitor is expected and compound specific monitors are important. A summary is given of the various well known methods of detecting tritium-in-air. This covers the direct as well as the indirect measuring techniques, although each has been continually improved and further developed, nevertheless, each has its own limitations. Ionization chambers cannot discriminate against airborne P emitters. Proportional counters have a narrow operating range, 3-4 decades, and have poor performance in relatively high humid environments and require a dry counting gas. Liquid scintillation counters are sensitive, but inspection of the sample is slow and they produce chemical liquid waste. A new way to improve the sensitivity of detecting tritium with plastic scintillators has been developed. The technique is based on a non-line-of-sight implantation of tritium ions into a 20 mum plastic scintillator using a plasma source ion implantation (PSII) technique, This type of source is different, superior to the line-of-sight implantation and requires no additional beam handling. It is capable of implanting ion species in a broad beam configuration into the entire surface of a target. The technique requires a special ion source with special characteristics of the type obtained from a surfatron plasma source. This ion source has a large high ion density plasma with minimum contamination and produces ions of low temperature. It was constructed to ionize the sampled air and to produce a plasma over a wide range of pressure, 4-0.1 mTorr. A plasma source ion implantation cell was designed and constructed using mathematical modeling with personal computer, to optimize the essential variables of the design and to estimate the implantation rate under different operation conditions. Also, a high voltage pulse modulator was designed and constructed to produce a series of 10 musec pulses (up to 2 MHz) with a maximum magnitude of -60 kV. The developed device was capable of ionizing air samples and implanting the resulting ions into a plastic scintillator. Two different methods to enhance the collection and deposition of the tritium ions, have been proposed and assessed. A movable prototype device for monitoring environmental tritium in air has been designed and constructed. Although this prototype was not fully tested, the primary calculations have shown that measurable concentrations of tritium ions can be collected from an air sample, with tritium activity ranging from 0.3 Bq/cm3 down to 0.03 mBq/cm3, in a short time, to the order of seconds, on-line. This sensitivity fulfills the requirement for environmental monitoring.

SU-E-I-88: The Effect of System Dead Time On Real-Time Plastic and GOS Based Fiber-Optic Dosimetry Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoerner, M; Hintenlang, D

Purpose: A methodology is presented to correct for measurement inaccuracies at high detector count rates using a plastic and GOS scintillation fibers coupled to a photomultiplier tube with digital readout. This system allows temporal acquisition and manipulation of measured data. Methods: The detection system used was a plastic scintillator and a separate gadolinium scintillator, both (0.5 diameter) coupled to an optical fiber with a Hamamatsu photon counter with a built-in microcontroller and digital interface. Count rate performance of the system was evaluated using the nonparalzable detector model. Detector response was investigated across multiple radiation sources including: orthovoltage x-ray system, colbat-60more » gamma rays, proton therapy beam, and a diagnostic radiography x-ray tube. The dead time parameter was calculated by measuring the count rate of the system at different exposure rates using a reference detector. Results: The system dead time was evaluated for the following sources of radiation used clinically: diagnostic energy x-rays, cobalt-60 gamma rays, orthovoltage xrays, particle proton accelerator, and megavoltage x-rays. It was found that dead time increased significantly when exposing the detector to sources capable of generating Cerenkov radiation, all of the sources sans the diagnostic x-rays, with increasing prominence at higher photon energies. Percent depth dose curves generated by a dedicated ionization chamber and compared to the detection system demonstrated that correcting for dead time improves accuracy. On most sources, nonparalzable model fit provided an improved system response. Conclusion: Overall, the system dead time was variable across the investigated radiation particles and energies. It was demonstrated that the system response accuracy was greatly improved by correcting for dead time effects. Cerenkov radiation plays a significant role in the increase in the system dead time through transient absorption effects attributed to electron hole-pair creations within the optical waveguide.« less

Performance evaluation of newly developed SrI2(Eu) scintillator

NASA Astrophysics Data System (ADS)

Takabe, M.; Kishimoto, A.; Kataoka, J.; Sakuragi, S.; Yamasaki, Y.

2016-09-01

The development of europium-doped strontium iodide (SrI2(Eu)) has attracted considerable attention, because of its excellent material properties as regards gamma-ray scintillator applications. These include its excellent energy resolution, high light output (> 80 , 000 ph / MeV), and high effective atomic number (Z=49). Here we report on the performance of ϕ 1 in×1 in SrI2(Eu) cylindrical crystals newly fabricated by Union Materials Inc. In this study, we measured the energy resolution and light output at 10 °C temperature intervals between -40 and 40 °C, using an optically coupled 2-in photomultiplier tube (PMT) (Super Bialkali, Hamamatsu). The SrI2(Eu) light output increased by 0.12%/°C as the temperature decreased. At -40 °C, we obtained the optimal energy resolution recording 2.91±0.02% full width at half maximum (FWHM) for 662 keV gamma rays measured with 137Cs. For comparison, we also measured the same crystal using both a large-area (19×19 mm2) avalanche photodiode detector (APD) and 8×8 multi-pixel photon counter (MPPC) arrays of 3×3 mm2 pixels. The energy resolutions of 2.94±0.02%, 3.14±0.06% and 3.99±0.01% were obtained using PMT, APD, and MPPC, respectively, as measured at -20 °C. We also measured the inherent background of SrI2(Eu) in a cave composed of Cu-Pb blocks with their thickness of 5-10 cm confirming that SrI2(Eu) has an extremely low inherent background radiation. In this study, we have shown that SrI2(Eu) is a promising scintillator that can be utilized for radiation measurements incorporating low-energy X-rays to high-energy gamma rays, and can thus be applied in various medical, industrial, and environmental treatment fields in the near future.

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

PubMed

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

2015-02-21

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

A PET detector prototype based on digital SiPMs and GAGG scintillators

NASA Astrophysics Data System (ADS)

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

2015-02-01

Silicon Photomultipliers (SiPM) are interesting light sensors for Positron Emission Tomography (PET). The detector signal of analog SiPMs is the total charge of all fired cells. Energy and time information have to be determined with dedicated readout electronics. Philips Digital Photon Counting has developed a SiPM with added electronics on cell level delivering a digital value of the time stamp and number of fired cells. These so called Digital Photon Counters (DPC) are fully digital devices. In this study, the feasibility of using DPCs in combination with LYSO (Lutetium Yttrium Oxyorthosilicate) and GAGG (Gadolinium Aluminum Gallium Garnet) scintillators for PET is tested. Each DPC module has 64 channels with 3.2 × 3.8775 mm2, comprising 3200 cells each. GAGG is a recently developed scintillator (Zeff = 54, 6.63 g cm-3, 520 nm peak emission, 46 000 photons MeV-1, 88 ns (92%) and 230 ns (8%) decay times, non-hygroscopic, chemically and mechanically stable). Individual crystals of 2 × 2 × 6 mm3 were coupled onto each DPC pixel. LYSO coupled to the DPC results in a coincidence time resolution (CTR) of 171 ps FWHM and an energy resolution of 12.6% FWHM at 511 keV. Using GAGG, coincidence timing is 310 ps FWHM and energy resolution is 8.5% FWHM. A PET detector prototype with 2 DPCs equipped with a GAGG array matching the pixel size (3.2 × 3.8775 × 8 mm3) was assembled. To emulate a ring of 10 modules, objects are rotated in the field of view. CTR of the PET is 619 ps and energy resolution is 9.2% FWHM. The iterative MLEM reconstruction is based on system matrices calculated with an analytical detector response function model. A phantom with rods of different diameters filled with 18F was used for tomographic tests.

A large area cosmic muon detector located at Ohya stone mine

NASA Technical Reports Server (NTRS)

Nii, N.; Mizutani, K.; Aoki, T.; Kitamura, T.; Mitsui, K.; Matsuno, S.; Muraki, Y.; Ohashi, Y.; Okada, A.; Kamiya, Y.

1985-01-01

The chemical composition of the primary cosmic rays between 10 to the 15th power eV and 10 to the 18th power eV were determined by a Large Area Cosmic Muon Detector located at Ohya stone mine. The experimental aims of Ohya project are; (1) search for the ultra high-energy gamma-rays; (2) search for the GUT monopole created by Big Bang; and (3) search for the muon bundle. A large number of muon chambers were installed at the shallow underground near Nikko (approx. 100 Km north of Tokyo, situated at Ohya-town, Utsunomiya-city). At the surface of the mine, very fast 100 channel scintillation counters were equipped in order to measure the direction of air showers. These air shower arrays were operated at the same time, together with the underground muon chamber.

The AMIGA enhancement of the Pierre Auger Observatory

NASA Astrophysics Data System (ADS)

Maldera, S.

2014-06-01

The AMIGA (Auger Muons and Infill for the Ground Array) enhancement of the Auger Surface Detector consists of a 23.5 km2 infill area instrumented with water-Cherenkov detector stations accompanied by 30 m2 of scintillator counters, buried 2.3 m underground. The spacing of 750 m between the surface detectors extends the energy range as low as 3 × 1017 eV, thus allowing the study of the energy region where the transition between galactic and extra-galactic cosmic rays is expected to take place. We describe the reconstruction of the events observed with the infill water-Cherenkov detector array and the derived energy spectrum. We also discuss the basic properties of the muon detector modules obtained from measurements and tests during the construction phase and from the first data in the field.

A laboratory information management system for the analysis of tritium (3H) in environmental waters.

PubMed

Belachew, Dagnachew Legesse; Terzer-Wassmuth, Stefan; Wassenaar, Leonard I; Klaus, Philipp M; Copia, Lorenzo; Araguás, Luis J Araguás; Aggarwal, Pradeep

2018-07-01

Accurate and precise measurements of low levels of tritium ( 3 H) in environmental waters are difficult to attain due to complex steps of sample preparation, electrolytic enrichment, liquid scintillation decay counting, and extensive data processing. We present a Microsoft Access™ relational database application, TRIMS (Tritium Information Management System) to assist with sample and data processing of tritium analysis by managing the processes from sample registration and analysis to reporting and archiving. A complete uncertainty propagation algorithm ensures tritium results are reported with robust uncertainty metrics. TRIMS will help to increase laboratory productivity and improve the accuracy and precision of 3 H assays. The software supports several enrichment protocols and LSC counter types. TRIMS is available for download at no cost from the IAEA at www.iaea.org/water. Copyright © 2018 Elsevier Ltd. All rights reserved.

Combined radioguided parathyroidectomy and intravenous vitamin D therapy for the treatment of uraemic hyperparathyroidism.

PubMed

Oyama, Yuko; Kazama, J James; Maruyama, Hiroki; Narita, Ichiei; Kanbayashi, Chizuko; Koyama, Yu; Omori, Tsukasa; Hatakeyama, Katsuyoshi; Gejyo, Fumitake

2003-06-01

Therapy combining radioguided parathyroidectomy (PTx) followed by intravenous maxacalcitol was given to a 50-year-old Japanese man referred for treatment of uraemic secondary hyperparathyroidism. After laboratory and radiological examinations, the patient underwent uncomplicated, successful surgery, but glands that had not been detected radiologically before the procedure became apparent with a scintillation counter immediately after the removal of the swollen gland. To prevent relapse of secondary hyperparathyroidism in the remaining glands, 10 microg of maxacalcitol was injected intravenously after each dialysis session. Following a minimally invasive radioisotope-guided PTx, the potential risk of relapse in the remaining glands has to be considered and intensive medical therapy should be instituted immediately after the operation. Further study needs to elucidate whether this treatment strategy can improve the long-term prognosis of patients with secondary hyperparathyroidism

A statistical rain attenuation prediction model with application to the advanced communication technology satellite project. 3: A stochastic rain fade control algorithm for satellite link power via non linear Markow filtering theory

NASA Technical Reports Server (NTRS)

Manning, Robert M.

1991-01-01

The dynamic and composite nature of propagation impairments that are incurred on Earth-space communications links at frequencies in and above 30/20 GHz Ka band, i.e., rain attenuation, cloud and/or clear air scintillation, etc., combined with the need to counter such degradations after the small link margins have been exceeded, necessitate the use of dynamic statistical identification and prediction processing of the fading signal in order to optimally estimate and predict the levels of each of the deleterious attenuation components. Such requirements are being met in NASA's Advanced Communications Technology Satellite (ACTS) Project by the implementation of optimal processing schemes derived through the use of the Rain Attenuation Prediction Model and nonlinear Markov filtering theory.

TeV electron measurement with CREST experiment

NASA Astrophysics Data System (ADS)

Park, Nahee; Anderson, T.; Bower, C.; Coutu, S.; Gennaro, J.; Geske, M.; Muller, D.; Musser, J.; Nutter, S.

CREST, the Cosmic Ray Electron Synchrotron Telescope is a balloon-borne experiment de-signed to measure the spectrum of multi-TeV electrons by the detection of the x-ray synchrotron photons generated in the magnetic field of the Earth. Electrons in the TeV range are expected to reflect the properties of local sources because fluxes from remote locations are suppressed by radiative losses during propagation. Since CREST needs to intersect only a portion of the kilometers-long trail of photons generated by the high-energy electron, the method yields a larger effective area than the physical size of the detector, boosting detection areas. The in-strument is composed of an array of 1024 BaF2 crystals and a set of scintillating veto counters. A long duration balloon flight in Antarctica is currently planned for the 2010-11 season.

Search for X rays from the planet Jupiter.

NASA Technical Reports Server (NTRS)

Hurley, K. C.

1972-01-01

Actively collimated balloon-borne scintillation counters employing a special phoswich anticoincidence technique were flown a total of 5 times from Palestine, Texas. Jupiter was observed for a total of 133 min, and an upper limit to the flux of X rays present at the observation time is .016 X rays/sq cm sec in the energy range 30-100 keV. Three separate calculations are made to estimate the flux of Jovian X rays at the earth. These estimates range from .000000001 to .1 X rays/sq cm sec in the energy range 30-100 keV. It is concluded that, since there was no decametric emission at the time of the flight and there had been no significant solar activity for several days prior to the flight, no X rays were being generated at the time of the observation.

A search for low energy gamma rays from CG 195+4

NASA Technical Reports Server (NTRS)

Haymes, R. C.; Meegan, C. A.; Fishman, G. J.

1979-01-01

A 13-deg-wide region of sky containing the high-energy gamma-ray source CG 195+4 was searched for X-ray and gamma-ray emission in the energy interval from 0.035 to 8.737 MeV. The balloon-altitude measurements were undertaken on October 4, 1977, at Palestine, Texas, and used an actively collimated scintillation counter. As a result of the measurements, low upper limits have been found for the spectrum from the source. Combined with the positive detections made with satellites at high energies, the measurements show that the photon number spectrum must have a spectral index harder than 2.0. The data appear inconsistent with models of the source in which the presumed neutron star is surrounded by a cloud thick to X-rays. Negative results of the search for periodicity are discussed.

Integral neutron kerma coefficient ratios for silicon, iron, and oxygen to carbon on the energy range from 15 to 30 MeV

NASA Astrophysics Data System (ADS)

Miranda, Juan Gustavo

2001-07-01

Kerma coefficient ratios are reported for carbon to oxygen, silicon, and iron in the energy range of 15 to 30 MeV. The determination was done by measuring dose to the gas of proportional counters exposed to a well characterized neutron field. The measured dose in the proportional counter gas was then converted to dose in the proportional counter wall material applying Bragg-Gray theory. The proportional counters were made of the material of interest. The oxygen measurement was done by irradiating simultaneously zirconium and zirconium oxide proportional counters and substracting the dose to the zirconium from the zirconium oxide. Neutrons were generated with the UW Tandem Accelerator. The reaction 3H(d, n)4 He provided our neutron source which consisted of monoenergetic neutrons. Neutron spectra measurements were carried out for the 27.3 MeV neutron energy. This was necessary because of the presence of contaminating breakup neutrons at this energy. The spectra were measured with a pulse beam time-of-flight spectrometer and a NE-213 liquid scintillator. The dose conversion factor r is reported for carbon, oxygen, silicon, iron, zirconium, and zirconium oxide relative to TE-propane gas at neutron energies of 20, 23 and 27 MeV. The factor r, which relates the dose to the gas to that of the proportional counter through the Bragg-Gray theory, was calculated from angle integrated differential cross sections. This required a calculation of the initial energy spectra as well as the differential secondary charged particle energy spectra and for the first time a complete treatment of all heavy ions is considered. Furthermore, as the conditions required to apply the Bragg-Gray theory are difficult to satisfy (infinitesimal cavity), we report the calculation of the dose conversion factor r for the finite cavity case for carbon/TE-gas in order to test the validity of the application of the theory to this type of applications. We found that the two conditions of the Bragg-Gray theory are violated: the differential secondary charged particle spectrum is perturbed by the presence of the cavity and that the dose absorbed in the cavity is not enteraly deposited by the particles crossing it. However, these changes in the spectra and the dose deposition are not very sensitive to the conversion factor r because this factor only reflects the ratio of these changes. Our results are found to be in agreement, within the uncertainty associated to the determination, with previous published values when comparable data exits.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slaughter, David M.; Stuart, Cory R.; Klaass, R. Fred

2015-07-01

This paper describes the development and testing of a neutron counter, spectrometer, and dosimeter that is compact, efficient, and accurate. A self-contained neutron detection instrument has wide applications in health physics, scientific research, and programs to detect, monitor, and control strategic nuclear materials (SNM). The 1.3 liter detector head for this instrument is a composite detector with an organic scintillator containing uniformly distributed {sup 6}Li{sub 6}{sup nat}Gd{sup 10}B{sub 3}O{sub 9}:Ce (LGB:Ce) microcrystals. The plastic scintillator acts to slow impinging neutrons and emits light proportional to the energy lost by the neutrons as they moderate in the detector body. Moderating neutronsmore » that have slowed sufficiently capture in one of the Lithium-6, Boron-10, or Gadolinium-157 atoms in the LGB:Ce scintillator, which then releases the capture energy in a characteristic cerium emission pulse. The measured captured pulses indicate the presence of neutrons. When a scintillating fluor is present in the plastic, the light pulse resulting from the neutron moderating in the plastic is paired with the LGB:Ce capture pulse to identify the energy of the neutron. About 2% of the impinging neutrons lose all of their energy in a single collision with the detector. There is a linear relationship between the pulse areas of this group of neutrons and energy. The other 98% of neutrons have a wide range of collision histories within the detector body. When these neutrons are 'binned' into energy groups, each group contains a distribution of pulse areas. This data was used to assist in the unfolding of the neutron spectra. The unfolded spectra were then validated with known spectra, at both neutron emitting isotopes and fission/accelerator facilities. Having validated spectra, the dose equivalent and dose rate are determined by applying standard, regulatory damage coefficients to the measured neutron counts for each energy bin of the spectra. Testing at the Los Alamos Neutron Science Center (LANSCE), Edwards Accelerator Laboratory (EAL) at Ohio University and the Radiation Center at University of Massachusetts-Lowell has demonstrated that the instrument can measure neutrons and their spectra over the range between 0.8 MeV and 150 MeV with an uncertainty of only ± 8%. An independent test of the LGB:Ce neutron spectrometer was conducted by a US Defense Threat Reduction Agency (DTRA) team at the Idaho National Laboratory (INL). The results of this evaluation showed that the neutron spectrometer accurately identified bare radioactive isotopes by their spectra. Further, masking and shielding materials alter those spectra in predictable ways that permit an extrapolation from the observed spectra back to the identity of the isotopic spectrum. (authors)« less

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.

Method, apparatus and system for low-energy beta particle detection

DOEpatents

Akers, Douglas W.; Drigert, Mark W.

2012-09-25

An apparatus, method, and system relating to radiation detection of low-energy beta particles are disclosed. An embodiment includes a radiation detector with a first scintillator and a second scintillator operably coupled to each other. The first scintillator and the second scintillator are each structured to generate a light pulse responsive to interaction with beta particles. The first scintillator is structured to experience full energy deposition of low-energy beta particles, and permit a higher-energy beta particle to pass therethrough and interact with the second scintillator. The radiation detector further includes a light-to-electrical converter 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 have at least one mutually different characteristic to enable an electronic system to determine whether a given light pulse is generated in the first scintillator or the second scintillator.

The radioactivity estimation of 14C and 3H in graphite waste samples of the KRR-2.

PubMed

Reyoung Kim, Hee

2013-09-01

The radioactivity of (14)C and (3)H in graphite samples from the dismantled Korea Research Reactor-2 (the KRR-2) site was analyzed by high-temperature oxidation and liquid scintillation counting, and the graphite waste was suggested to be disposed of as a low-level radioactive waste. The graphite samples were oxidized at a high temperature of 800 °C, and their counting rates were measured by using a liquid scintillation counter (LSC). The combustion ratio of the graphite was about 99% on the sample with a maximum weight of 1g. The recoveries from the combustion furnace were around 100% and 90% in (14)C and (3)H, respectively. The minimum detectable activity was 0.04-0.05 Bq/g for the (14)C and 0.13-0.15 Bq/g for the (3)H at the same background counting time. The activity of (14)C was higher than that of (3)H over all samples with the activity ratios of the (14)C to (3)H, (14)C/(3)H, being between 2.8 and 25. The dose calculation was carried out from its radioactivity analysis results. The dose estimation gave a higher annual dose than the domestic legal limit for a clearance. It was thought that the sampled graphite waste from the dismantled research reactor was not available for reuse or recycling and should be monitored as low-level radioactive waste. Copyright © 2013 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Fredrick

Thesis. The development of a directional high energy (20 to 160 MeV) neutron detector which was flown to satellite altitudes (500 km; circular equatorial orbit) in the NASA Orbiting Solar Observatory (OSO-6) in August 1969 is described. Both the angle of incidence and the energy of the neutron are determined by a proton-recoil telescope (Pilot B scintillation plastic) which provides the source for proton-recoils and defines the dE/dX versus E method for particle identification and energy determination. The telescope is embedded in a scintillation plastic guard counter envelope which eliminates the unwanted charged particle background as well as recoil protonsmore » (electrons) whose energies and direction do not satisfy neutron (gamma-ray) detection requirements, respectively. Results from a Monte Carlo calculation indicate that the overall average efficiency within an average angular acceptance of about 29 deg (FWHM) is approximately (2.25 plus or minus 0.113) x 10/sup -4/. The inflight calibration procedure, the main frame data bit error analysis, and the method for determining the orientation of the detector axis in the spacecraft spin plane are described. Results indicate a discrepancy in the measured (0.461 x 10/sup -2/ plus or minus 0.254 x 10/sup -2/ n/cm/sup 2/sec) and theoretical (2 to 70 n/cm/ sup 2/sec) neutron flux es which suggests a lack of basic underatanding of mechanisms leading to high energy neutron production at the sun. (auth)« less

DETERMINATION OF THE BACKGROUND WHILE MEASURING ACTIVITIES OF THE ORDER OF 10$sup -11$ TO 10$sup -13$ CURIE (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artem'ev, V.V.

1962-11-01

Activity measurements must be occasionally carried out in presence of a background radiation with a higher value than the radiation under study. Such cases are encountered in geological prospecting, biological and medical experiments with isotopes having half life periods longer than 10 years, requiring instruments with sensisitivities exceeding the 10/sup -13/ to 10/sup - 14/ curie range. Measurement of activities from 10/sup -11/ to 10/sup -13/ curie with an error of less than 1% requires tens of hours during which the background may vary radically because of the variations of cosmic rays and solar flares. In radiochemical dating studies themore » background usually consists of a constant component due to natural radioactive materials such as KID, and decay products of the U and Th series, and of a variable component primarily controlled by the cosmic radiation. Multiple scattering and absorption events cause a spreading of the spectral lines in neighboring portions of the spectrum of the background radiation; the changes in the second component may be determined by decomposing the count rate. The method was used successfully in mass determinations of C/sup 14/ in geological and archeological samples. The C sample was used to prepare ethyl benzene in which scintillating compounds, such as 2,5 diphenyl oxazol and 1,4-STAdi2,5 phenyl oxazolyl! benzene were dissolved, measuring the activity by means of a scintillation counter and a photomultiplier. (TTT)« less

Degradation of Triazine-2-14C Metsulfuron–Methyl in Soil from an Oil Palm Plantation

PubMed Central

B. S., Ismail

2015-01-01

Triazine-2-14C metsulfuron–methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-14C metsulfuron–methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP–1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT50 and DT90 values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT50 and DT90 were 31 and 70 days, respectively. The principal degradation product after 60 days was CO2. The higher cumulative amount of 14CO2 in 14C- triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine “ring-opened.” PMID:26437264

Kinetic Monte Carlo Simulations of Scintillation Processes in NaI(Tl)

NASA Astrophysics Data System (ADS)

Kerisit, Sebastien; Wang, Zhiguo; Williams, Richard T.; Grim, Joel Q.; Gao, Fei

2014-04-01

Developing a comprehensive understanding of the processes that govern the scintillation behavior of inorganic scintillators provides a pathway to optimize current scintillators and allows for the science-driven search for new scintillator materials. Recent experimental data on the excitation density dependence of the light yield of inorganic scintillators presents an opportunity to incorporate parameterized interactions between excitations in scintillation models and thus enable more realistic simulations of the nonproportionality of inorganic scintillators. Therefore, a kinetic Monte Carlo (KMC) model of elementary scintillation processes in NaI(Tl) is developed in this paper to simulate the kinetics of scintillation for a range of temperatures and Tl concentrations as well as the scintillation efficiency as a function of excitation density. The ability of the KMC model to reproduce available experimental data allows for elucidating the elementary processes that give rise to the kinetics and efficiency of scintillation observed experimentally for a range of conditions.

X-ray absorption fine structure (XAFS) spectroscopy using synchrotron radiation

NASA Astrophysics Data System (ADS)

Shrivastava, B. D.

2012-05-01

The X-ray absorption fine structure (XAFS) spectra are best recorded when a highly intense beam of X-rays from a synchrotron is used along with a good resolution double crystal or curved crystal spectrometer and detectors like ionization chambers, scintillation counters, solid state detectors etc. Several synchrotrons around the world have X-ray beamlines dedicated specifically to XAFS spectroscopy. Fortunately, the Indian synchrotron (Indus-2) at Raja Ramanna Centre for Advanced Technology (RRCAT) at Indore has started operation. A dispersive type EXAFS beamline called BL-8 has been commissioned at this synchrotron and another beamline having double crystal monochromator (DCM) is going to be commissioned shortly. In Indian context, in order that more research workers use these beamlines, the study of XAFS spectroscopy using synchrotron radiation becomes important. In the present work some of the works done by our group on XAFS spectroscopy using synchrotron radiation have been described.

Inverse Flux versus Pressure of Muons from Cosmic Rays

NASA Astrophysics Data System (ADS)

Buitrago, D.; Armendariz, R.

2017-12-01

When an incoming cosmic ray proton or atom collides with particles in earth's atmosphere a shower of secondary muons is created. Cosmic ray muon flux was measured at the Queensborough Community College using a QuarkNet detector consisting of three stacked scintillator muon counters and a three-fold coincidence trigger. Data was recorded during a three-day period during a severe weather storm that occurred from March 13-17, 2017. A computer program was created in Python to read the muon flux rate and atmospheric pressure sensor readings from the detector's data acquisition board. The program converts the data from hexadecimal to decimal, re-bins the data in a more suitable format, creates and overlays plots of muon flux with atmospheric pressure. Results thus far show a strong correlation between muon flux and atmospheric pressure. More data analysis will be done to verify the above conclusion.

X-ray observations of AM Herculis from OSO 8

NASA Technical Reports Server (NTRS)

Coe, M. J.; Dennis, B. R.; Dolan, J. F.; Crannell, C. J.; Frost, K. J.; Orwig, I. E.

1979-01-01

X-ray observations of the white dwarf binary system AM Herculis in the range 2 to 250 keV, taken by OSO 8, are presented and compared with balloon and Ariel 5 measurements. The composite spectrum of the 2 to 40 and 20 to 250 keV fluxes determined by the proportional counter and the high energy scintillation spectrometer, respectively, on board the satellite is shown averaged over the entire binary cycle. Variations in spectral shape and intensity between the OSO 8 results and balloon measurements taken 10 to 20 days apart are observed. Results indicate the presence of a spectral break at about 15 keV on some occasions, similar to that seen in Her X-1, however presumably caused by a different mechanism than in the neutron star. It is also considered unlikely that the gamma-ray tail observed by Ariel 5 existed during OSO 8 observations.

Telescope Array Low energy Extension: TALE

NASA Astrophysics Data System (ADS)

Ogio, Shoichi

TALE, the Telescope Array Low Energy extension was designed to lower the energy threshold to about 1016.5 eV. TALE has a surface detector (SD) array made up of 103 scintillation counters (40 with 400 m spacing, 36 with 600 m spacing and 27 with 1.2 km spacing) and a Fluorescence Detector (FD) station consisting of ten FD telescopes working with the Telescope Array Middle Drum FD station, which is made up of 14 telescopes. TALE-FD full operation started in 2013 and the SD array was partially-completed with 16 SDs and continues the operation from 2014. We will describe the history and the current status of the detectors and will make a brief report about the FD and the hybrid analysis results. TALE detector will be completed as a hybrid air shower detector in 2018. We will report the technical details of the detectors, the schedule and the expected performances.

A compact tritium enrichment unit for large sample volumes with automated re-filling and higher enrichment factor.

PubMed

Kumar, B; Han, L-F; Wassenaar, L I; Klaus, P M; Kainz, G G; Hillegonds, D; Brummer, D; Ahmad, M; Belachew, D L; Araguás, L; Aggarwal, P

2016-12-01

Tritium ( 3 H) in natural waters is a powerful tracer of hydrological processes, but its low concentrations require electrolytic enrichment before precise measurements can be made with a liquid scintillation counter. Here, we describe a newly developed, compact tritium enrichment unit which can be used to enrich up to 2L of a water sample. This allows a high enrichment factor (>100) for measuring low 3 H contents of <0.05TU. The TEU uses a small cell (250mL) with automated re-filling and a CO 2 bubbling technique to neutralize the high alkalinity of enriched samples. The enriched residual sample is retrieved from the cell under vacuum by cryogenic distillation at -20°C and the tritium enrichment factor for each sample is accurately determined by measuring pre- and post- enrichment 2 H concentrations with laser spectrometry. Copyright © 2016. Published by Elsevier Ltd.

Results of the CCRI(II)-S12.H-3 supplementary comparison: Comparison of methods for the calculation of the activity and standard uncertainty of a tritiated-water source measured using the LSC-TDCR method.

PubMed

Cassette, Philippe; Altzitzoglou, Timotheos; Antohe, Andrei; Rossi, Mario; Arinc, Arzu; Capogni, Marco; Galea, Raphael; Gudelis, Arunas; Kossert, Karsten; Lee, K B; Liang, Juncheng; Nedjadi, Youcef; Oropesa Verdecia, Pilar; Shilnikova, Tanya; van Wyngaardt, Winifred; Ziemek, Tomasz; Zimmerman, Brian

2018-04-01

A comparison of calculations of the activity of a 3 H 2 O liquid scintillation source using the same experimental data set collected at the LNE-LNHB with a triple-to-double coincidence ratio (TDCR) counter was completed. A total of 17 laboratories calculated the activity and standard uncertainty of the LS source using the files with experimental data provided by the LNE-LNHB. The results as well as relevant information on the computation techniques are presented and analysed in this paper. All results are compatible, even if there is a significant dispersion between the reported uncertainties. An output of this comparison is the estimation of the dispersion of TDCR measurement results when measurement conditions are well defined. Copyright © 2017 Elsevier Ltd. All rights reserved.

Progress in Search for Antihelium with BESS

NASA Technical Reports Server (NTRS)

Sasaki, M.; Matsumoto, H.; Nozaki, M.; Saeki, T.; Abe, K.; Anraku, K.; Asoka, Y.; Fujikawa, M.; Fuke, H.; Imori, M.

2002-01-01

We have searched for antihelium nuclei in cosmic rays using the data obtained from balloon flights of the BESS magnetic spectrometer. The search was mainly based on track-quality selection, followed by rigidity analysis, and on the time-of-flight and dE/dx measurements by the scintillation counter hodoscope. We analysed all the data collected during 1993-2000 with a common analysis procedure. No antihelium nuclei events were found in the energy range from 1 to 14 GV. In order to determine a new upper limit, we have simulated the loss in the air and in the instrument of He (He-bar) using the GEANT/GHEISHA code. Combined with the data collected in 1993 through 2000, a new 95 % confidence upper limit for the ratio of He-bar/He at the top of the atmosphere of 6.8 x 10(exp -7) has been obtained to be after correcting for the interactions in the air and in the instruments.

Measurement of x-ray spectra using a recent YAP(Ce)-MPPC detector

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Oda, Yasuyuki; Yoshida, Sohei; Yamaguchi, Satoshi; Sato, Yuichi; Ishii, Tomotaka; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya

2017-09-01

To measure X-ray spectra with high count rates, we developed a detector consisting of a cerium-doped yttrium aluminum perovskite [YAP(Ce)] crystal and a recent multipixel photon counter (MPPC). Scintillation photons are detected using the MPPC, and the photocurrents flowing through the MPPC are converted into voltages and amplified using a high-speed current-voltage (I-V) amplifier. The MPPC bias voltage was set to a value at the pre-Geiger mode to perform zero-dark counting. The event-pulse widths were approximately 200 ns, and the widths were extend to approximately 1 μs. X-ray spectra were measured using a multichannel analyzer (MCA) for pulse-height analysis. The photon energy was roughly determined by the two-point calibration using tungsten K photons and iodine K fluorescence. Using the YAP(Ce)-MPPC detector, first-generation dual-energy computed tomography was accomplished using iodine and gadolinium contrast media.

Measurement of the cariogenicity of snacks using a radioisotope PAHA disc.

PubMed

Lee, Eun-Jung; Yun, Hye-Kyoung; Hwang, In-Kyeong; Bae, Kwang-Hak; Jin, Bo-Hyoung; Paik, Dai-il

2012-06-01

This study aimed to establish a method for measuring the cariogenic potential of foods with high reproducibility in vitro. Streptococcus mutans (S. mutans) was incubated in test foods with radioisotope polyacrylamide hydroxyapatite (PAHA) for 150 min at 37 °C. Then, the amount of radioisotope (32)P released from PAHA was measured using a liquid scintillation counter and scanning electron microscopy (SEM). The radioisotope PAHA discs that were soaked in 10% sucrose solutions had a high cariogenic potential and showed a remarkably demineralized surface (p < 0.05). The radioisotope PAHA disc that was incubated with snacks that had a high cariogenic potential showed a remarkably demineralized surface via SEM. Candy had a relatively high cariogenic potential, whereas xylitol gum had a relatively low potential. The cariogenicity of snacks can easily be evaluated by measuring the amount of (32)P released from radioisotope PAHA discs. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cosmic-ray elemental abundances from 1 to 10 GeV per amu for boron through nickel

NASA Technical Reports Server (NTRS)

Dwyer, Robert; Meyer, Peter

1987-01-01

The relative abundances of cosmic-ray nuclei in the charge range boron through nickel over the energy range 1-10 GeV per amu were measured with a balloon-borne detector. The instrument consists of a scintillation and Cerenkov counter telescope with a multiwire proportional chamber hodoscope and has been flown in four high-altitude balloon flights. Good charge resolution (sigma = 0.2 charge units at iron) and high statistical accuracy have been achieved. These data are used to derive the energy dependence of the leakage path length using the leaky box model of propagation and confinement in the galaxy. This energy dependence is found to be best fit by lambda = E(tot) exp -n, where n = 0.49 + or - 0.06 over 1-10 GeV per amu. Relative abundances at the source are consistent with an energy-independent composition.

Rapid sequential determination of Pu, 90Sr and 241Am nuclides in environmental samples using an anion exchange and Sr-Spec resins.

PubMed

Lee, M H; Ahn, H J; Park, J H; Park, Y J; Song, K

2011-02-01

This paper presents a quantitative and rapid method of sequential separation of Pu, (90)Sr and (241)Am nuclides in environmental soil samples with an anion exchange resin and Sr Spec resin. After the sample solution was passed through an anion exchange column connected to a Sr Spec column, Pu isotopes were purified from the anion exchange column. Strontium-90 was separated from other interfering elements by the Sr Spec column. Americium-241 was purified from lanthanides by the anion exchange resin after oxalate co-precipitation. Measurement of Pu and Am isotopes was carried out using an α-spectrometer. Strontium-90 was measured by a low-level liquid scintillation counter. The radiochemical procedure of Pu, (90)Sr and (241)Am nuclides investigated in this study validated by application to IAEA reference materials and environmental soil samples. Copyright © 2010 Elsevier Ltd. All rights reserved.

Measurements of underlying-event properties using neutral and charged particles in pp collisions at $$\\sqrt{s}=900$$ GeV and $$\\sqrt{s}=7$$ TeV with the ATLAS detector at the LHC

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2011-05-10

We present first measurements of charged and neutral particle-flow correlations in pp collisions using the ATLAS calorimeters. Data were collected in 2009 and 2010 at centre-of-mass energies of 900 GeV and 7 TeV. Events were selected using a minimum-bias trigger which required a charged particle in scintillation counters on either side of the interaction point. Particle flows, sensitive to the underlying event, are measured using clusters of energy in the ATLAS calorimeters, taking advantage of their fine granularity. No Monte Carlo generator used in this analysis can accurately describe the measurements. The results are independent of those based on chargedmore » particles measured by the ATLAS tracking systems and can be used to constrain the parameters of Monte Carlo generators.« less

Isotopic composition of cosmic ray nitrogen at 1.5 GeV/amu

NASA Technical Reports Server (NTRS)

Dwyer, R.; Meyer, P.

1975-01-01

For any location, the earth's magnetic field acts as a filter for incoming cosmic rays, allowing only particles above a certain rigidity. The relative isotopic composition of abundant elements can be measured with a detector sensitive to the velocity of particles in the penumbra of the earth's magnetic field. In this paper, the nitrogen velocity spectrum is compared with that of carbon plus oxygen as a reference, since in this case Z-dependent effects are minimal. The form of the energy spectrum of carbon, nitrogen, and oxygen, needed for proper correction, was measured in the same experiment. The results were obtained using a scintillator-Cerenkov counter telescope with a geometric factor of 0.25 sq in sr, flown twice on high-altitude balloons from Palestine, Texas, obtaining an exposure factor of 20 sq m sr hr. Results are presented on the isotopic composition of nitrogen at about 1.5GeV/amu.

Neutron skyshine from intense 14-MeV neutron source facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, T.; Hayashi, K.; Takahashi, A.

1985-07-01

The dose distribution and the spectrum variation of neutrons due to the skyshine effect have been measured with the high-efficiency rem counter, the multisphere spectrometer, and the NE-213 scintillator in the environment surrounding an intense 14-MeV neutron source facility. The dose distribution and the energy spectra of neutrons around the facility used as a skyshine source have also been measured to enable the absolute evaluation of the skyshine effect. The skyshine effect was analyzed by two multigroup Monte Carlo codes, NIMSAC and MMCR-2, by two discrete ordinates S /sub n/ codes, ANISN and DOT3.5, and by the shield structure designmore » code for skyshine, SKYSHINE-II. The calculated results show good agreement with the measured results in absolute values. These experimental results should be useful as benchmark data for shyshine analysis and for shielding design of fusion facilities.« less

Optimizing ZnS/6LiF scintillators for wavelength-shifting-fiber neutron detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crow, Lowell; Funk, Loren L; Hannan, Bruce W

2016-01-01

In this paper we compare the performance of grooved and flat ZnS/6LiF scintillators in a wavelength shifting-fiber (WLSF) detector. Flat ZnS/6LiF scintillators with the thickness L=0.2-0.8 mm were characterized using photon counting and pulse-height analysis and compared to a grooved scintillator of approximately 0.8 mm thick. While a grooved scintillator considerably increases the apparent thickness of the scintillator to neutrons for a given coating thickness, we find that the flat scintillators perform better than the grooved scintillators in terms of both light yield and neutron detection efficiency. The flat 0.8-mm-thick scintillator has the highest light output, and it is 52%more » higher compared with a grooved scintillator of same thickness. The lower light output of the grooved scintillator as compared to the flat scintillator is consistent with the greater scintillator-WLSF separation and the much larger average emission angle of the grooved scintillator. We also find that the average light cone width, or photon travel-length as measured using time-of-flight powder diffraction of diamond and vanadium, decreases with increasing L in the range of L=0.6-0.8 mm. This result contrasts with the traditional Swank diffusion model for micro-composite scintillators, and could be explained by a decrease in photon diffusion-coefficient or an increase in micro-particle content in the flat scintillator matrix for the thicker scintillators.« less

Kinetic Monte Carlo simulations of scintillation processes in NaI(Tl)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerisit, Sebastien N.; Wang, Zhiguo; Williams, Richard

2014-04-26

Developing a comprehensive understanding of the processes that govern the scintillation behavior of inorganic scintillators provides a pathway to optimize current scintillators and allows for the science-driven search for new scintillator materials. Recent experimental data on the excitation density dependence of the light yield of inorganic scintillators presents an opportunity to incorporate parameterized interactions between excitations in scintillation models and thus enable more realistic simulations of the nonproportionality of inorganic scintillators. Therefore, a kinetic Monte Carlo (KMC) model of elementary scintillation processes in NaI(Tl) is developed in this work to simulate the kinetics of scintillation for a range of temperaturesmore » and Tl concentrations as well as the scintillation efficiency as a function of excitation density. The ability of the KMC model to reproduce available experimental data allows for elucidating the elementary processes that give rise to the kinetics and efficiency of scintillation observed experimentally for a range of conditions.« less

Analysis of Ionospheric Scintillation Characteristics in Sub-Antarctica Region with GNSS Data at Macquarie Island.

PubMed

Guo, Kai; Liu, Yang; Zhao, Yan; Wang, Jinling

2017-01-12

Ionospheric scintillation has a great impact on radio propagation and electronic system performance, thus is extensively studied currently. The influence of scintillation on Global Navigation Satellite System (GNSS) is particularly evident, making GNSS an effective medium to study characteristics of scintillation. Ionospheric scintillation varies greatly in relation with temporal and spatial distribution. In this paper, both temporal and spatial characteristics of scintillation are investigated based on Macquarie Island's GNSS scintillation data collected from 2011 to 2015. Experiments demonstrate that occurrence rates of amplitude scintillation have a close relationship with solar activity, while phase scintillation is more likely to be generated by geomagnetic activity. In addition, scintillation distribution behaviors related to elevation and azimuth angles are statistically analyzed for both amplitude and phase scintillation. The proposed work is valuable for a deeper understanding of theoretical mechanisms of ionospheric scintillation in this region, and provides a reference for GNSS applications in certain regions around sub-Antarctica.

Fiber optic thermal/fast neutron and gamma ray scintillation detector

DOEpatents

Neal, John S.; Mihalczo, John T

2007-10-30

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

Calculations and measurements of the scintillator-to-water stopping power ratio of liquid scintillators for use in proton radiotherapy.

PubMed

Ingram, W Scott; Robertson, Daniel; Beddar, Sam

2015-03-11

Liquid scintillators are a promising detector for high-resolution three-dimensional proton therapy dosimetry. Because the scintillator comprises both the active volume of the detector and the phantom material, an ideal scintillator will exhibit water equivalence in its radiological properties. One of the most fundamental of these is the scintillator's stopping power. The objective of this study was to compare calculations and measurements of scintillator-to-water stopping power ratios to evaluate the suitability of the liquid scintillators BC-531 and OptiPhase HiSafe 3 for proton dosimetry. We also measured the relative scintillation output of the two scintillators. Both calculations and measurements show that the linear stopping power of OptiPhase is significantly closer to water than that of BC-531. BC-531 has a somewhat higher scintillation output. OptiPhase can be mixed with water at high concentrations, which further improves its scintillator-to-water stopping power ratio. However, this causes the solution to become cloudy, which has a negative impact on the scintillation output and spatial resolution of the detector. OptiPhase is preferred over BC-531 for proton dosimetry because its density and scintillator-to-water stopping power ratio are more water equivalent.

A sub-millimeter resolution PET detector module using a multi-pixel photon counter array

NASA Astrophysics Data System (ADS)

Song, Tae Yong; Wu, Heyu; Komarov, Sergey; Siegel, Stefan B.; Tai, Yuan-Chuan

2010-05-01

A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 × 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 × 0.8 × 3 mm3 and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 × 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and ±5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when ±10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing among multiple MPPC and to diffuse and direct scintillation light can reduce the nonlinearity of the detector response within the limited dynamic range of a typical MPPC. As a result, the proposed PET detector module has the potential to be refined for use in high-resolution PET insert applications.

A search for fast moving magnetic monopoles with the MACRO detector

NASA Astrophysics Data System (ADS)

Liu, Rongzhi

From Dirac monopole theory to modern GUT's (Grand Unified Theories), magnetic monopoles have attracted much attention from physicists. While Dirac had demonstrated the consistency of magnetic monopoles with quantum eletrodynamics, 't Hooft and Polyakov demonstrated the necessity of monopoles in GUT's. Furthermore, the GUT's supply more clues about magnetic monopoles, including their exceptionally heavy masses ~10[superscript 16] GeV. Both current theories and previous monopole experiments have suggested that the flux of magnetic monopoles is likely to be very small, so it is necessary to have a large area detector to search for them. This thesis presents a search for fast moving magnetic monopoles with the MACRO detector.The MACRO detector is a large underground detector located at Gran Sasso, Italy. Its primary goal is to search for magnetic monopoles at a flux level beyond the Parker bound. It is underground at 3,000 meters water equivalent depth, with a nominal acceptance of 10,000 m[superscript 2] sr. It employs liquid scintillator counters, streamer tubes and track-etch detectors which can supply both independent and cross checks for fast monopole candidate events.This search is mainly based on the liquid scintillator counters with primary event selection and energy reconstruction from the ERP system. The 6.2 [mu]s trigger time is based on the time of flight of a fast moving monopole diagonally through one supermodule with a velocity ~10[superscript -2]c. The search uses the "six-month-run" data which were taken from December of 1992 to July of 1993 with the operation of the lower part of the detector. With energy reconstruction ability up to 8 GeV with 22% error, we apply a double-face high energy requirement to reject most muon events from the data sample. We then apply the WFD, streamer tube and strip information to reject non-monopole events.The live time for this analysis is 5,300 hours, with acceptance of 4050 m[superscript 2]sr. With no fast monopole candidate event found, we establish an upper flux limit for the fast moving magnetic monopole at 90% confidence level of 3.03 x 10[superscript -15] cm[superscript -2]sr[superscript -1]s[superscript -1] for velocities from 10[superscript -2]c to 1.0c.

A Search for Fast Moving Magnetic Monopoles with the MACRO Detector

NASA Astrophysics Data System (ADS)

Liu, Rongzhi

1995-01-01

From Dirac monopole theory to modern GUT's (Grand Unified Theories), magnetic monopoles have attracted much attention from physicists. While Dirac had demonstrated the consistency of magnetic monopoles with quantum eletrodynamics, 't Hooft and Polyakov demonstrated the necessity of monopoles in GUT's. Furthermore, the GUT's supply more clues about magnetic monopoles, including their exceptionally heavy masses ~ 10^{16 } GeV. Both current theories and previous monopole experiments have suggested that the flux of magnetic monopoles is likely to be very small, so it is necessary to have a large area detector to search for them. This thesis presents a search for fast moving magnetic monopoles with the MACRO detector. The MACRO detector is a large underground detector located at Gran Sasso, Italy. Its primary goal is to search for magnetic monopoles at a flux level beyond the Parker bound. It is underground at 3,000 meters water equivalent depth, with a nominal acceptance of 10,000 m^2 sr. It employs liquid scintillator counters, streamer tubes and track-etch detectors which can supply both independent and cross checks for fast monopole candidate events. This search is mainly based on the liquid scintillator counters with primary event selection and energy reconstruction from the ERP system. The 6.2 mus trigger time is based on the time of flight of a fast moving monopole diagonally through one supermodule with a velocity ~ 10^{-2}c. The search uses the "six-month-run" data which were taken from December of 1992 to July of 1993 with the operation of the lower part of the detector. With energy reconstruction ability up to 8 GeV with 22% error, we apply a double-face high energy requirement to reject most muon events from the data sample. We then apply the WFD, streamer tube and strip information to reject non-monopole events. The live time for this analysis is 5,300 hours, with acceptance of 4050 m^2 sr. With no fast monopole candidate event found, we establish an upper flux limit for the fast moving magnetic monopole at 90% confidence level of 3.03 times 10^{-15} cm^ {-2}sr^{-1}s ^{-1} for velocities from 10^{-2}c to 1.0c.

A sub-millimeter resolution PET detector module using a multi-pixel photon counter array.

PubMed

Song, Tae Yong; Wu, Heyu; Komarov, Sergey; Siegel, Stefan B; Tai, Yuan-Chuan

2010-05-07

A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 x 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 x 0.8 x 3 mm(3) and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 x 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and +/-5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when +/-10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing among multiple MPPC and to diffuse and direct scintillation light can reduce the nonlinearity of the detector response within the limited dynamic range of a typical MPPC. As a result, the proposed PET detector module has the potential to be refined for use in high-resolution PET insert applications.

A sub-millimeter resolution PET detector module using a multi-pixel photon counter array

PubMed Central

Song, Tae Yong; Wu, Heyu; Komarov, Sergey; Siegel, Stefan B; Tai, Yuan-Chuan

2010-01-01

A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 × 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 × 0.8 × 3 mm3 and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 × 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and ±5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when ±10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing among multiple MPPC and to diffuse and direct scintillation light can reduce the nonlinearity of the detector response within the limited dynamic range of a typical MPPC. As a result, the proposed PET detector module has the potential to be refined for use in high-resolution PET insert applications. PMID:20393236

Isotopic response with small scintillator based gamma-ray spectrometers

DOEpatents

Madden, Norman W [Sparks, NV; Goulding, Frederick S [Lafayette, CA; Asztalos, Stephen J [Oakland, CA

2012-01-24

The intrinsic background of a gamma ray spectrometer is significantly reduced by surrounding the scintillator with a second scintillator. This second (external) scintillator surrounds the first scintillator and has an opening of approximately the same diameter as the smaller central scintillator in the forward direction. The second scintillator is selected to have a higher atomic number, and thus has a larger probability for a Compton scattering interaction than within the inner region. Scattering events that are essentially simultaneous in coincidence to the first and second scintillators, from an electronics perspective, are precluded electronically from the data stream. Thus, only gamma-rays that are wholly contained in the smaller central scintillator are used for analytic purposes.

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.

Influence of coma aberration on aperture averaged scintillations in oceanic turbulence

NASA Astrophysics Data System (ADS)

Luo, Yujuan; Ji, Xiaoling; Yu, Hong

2018-01-01

The influence of coma aberration on aperture averaged scintillations in oceanic turbulence is studied in detail by using the numerical simulation method. In general, in weak oceanic turbulence, the aperture averaged scintillation can be effectively suppressed by means of the coma aberration, and the aperture averaged scintillation decreases as the coma aberration coefficient increases. However, in moderate and strong oceanic turbulence the influence of coma aberration on aperture averaged scintillations can be ignored. In addition, the aperture averaged scintillation dominated by salinity-induced turbulence is larger than that dominated by temperature-induced turbulence. In particular, it is shown that for coma-aberrated Gaussian beams, the behavior of aperture averaged scintillation index is quite different from the behavior of point scintillation index, and the aperture averaged scintillation index is more suitable for characterizing scintillations in practice.

Assessment of scintillation proxy maps for a scintillation study during geomagnetically quiet and disturbed conditions over Uganda

NASA Astrophysics Data System (ADS)

Amabayo, Emirant B.; Jurua, Edward; Cilliers, Pierre J.

2017-02-01

The objective of this paper is demonstrate the validity and usefulness of scintillation proxies derived from IGS data, through its comparison with data from dedicated scintillation monitors and its application to GNSS scintillation patterns. The paper presents scintillation patterns developed by using data from the dedicated scintillation monitors of the scintillation network decision aid (SCINDA) network, and proxy maps derived from IGS GPS data for 2011 and 2012 over low latitude stations in Uganda. The amplitude and phase scintillation indicies (S4 and σΦ) were obtained from the Novatel GSV4004B ionospheric scintillation and total electron content (TEC) monitor managed by SCINDA at Makerere (0.340N, 32.570E). The corresponding IGS GPS proxy data were obtained from the receivers at Entebbe (0.040N, 32.440E) and Mbarara (0.600S, 30.740E). The derived amplitude (S4p) and phase (sDPR) scintillation proxy maps were compared with maps of S4 and σΦ during geomagnetic storms (moderate and strong) and geomagnetically quiet conditions. The scintillation patterns using S4 and σΦ and their respective proxies revealed similar diurnal and seasonal patterns of strong scintillation occurrence. The peaks of scintillation occurrence with mean values in the range 0.3 < (S4p , sDPR) ≤ 0.6 were observed during nighttime (17:00-22:00 UT) and in the months of March-April and September-October. The results also indicate that high level scintillations occur during geomagnetically disturbed (moderate and strong) and quiet conditions over the Ugandan region. The results show that SCINDA and IGS based scintillation patterns reveal the same nighttime and seasonal occurrence of irregularities over Uganda irrespective of the geomagnetic conditions. Therefore, the amplitude and phase scintillation proxies presented here can be used to fill gaps in low-latitude data where there are no data available from dedicated scintillation receivers, irrespective of the geomagnetic conditions.

Preparation of New Scintillation Imaging Material Composed of Scintillator-Silica Fine Powders and its Imaging of Tritium.

PubMed

Miyoshi, Hirokazu; Hiroura, Mitsunori; Tsujimoto, Kazunori; Irikura, Namiko; Otani, Tamaki; Shinohara, Yasuo

2017-05-01

A new scintillation imaging material [scintillator-silica fine powder (FP)] was prepared using silica FPs and scintillator-encapsulating silica nanoparticles (NPs) (scintillator-silica NPs). The wt% values of scintillator-silica NPs on the scintillator-silica FPs were 38, 43, 36 and 44%. Scintillation images of 3H, 63Ni, 35S, 33P, 204Tl, 89Sr and 32P dropped on the scintillator-silica FPs were obtained at about 37 kBq per 0.1-10 µl with a charge-coupled device (CCD) imager for a 5 min exposure. In particular, high-intensity CCD images of 35S were selectively obtained using the 2.25, 4.77 and 10 µm silica FPs with scintillator-silica NPs owing to the residual S of dimethyl sulfoxide in the preparation. Scintillation images of 3H at 1670 ± 9 Bq/0.5 µl and 347 ± 6 Bq/0.5 µl dropped in a 2 mm hole on the scintillator-silica FPs (6.78 and 10 µm) were also obtained using the CCD imager for a 2 h exposure. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Calculations and measurements of the scintillator-to-water stopping power ratio of liquid scintillators for use in proton radiotherapy

PubMed Central

Ingram, W. Scott; Robertson, Daniel; Beddar, Sam

2015-01-01

Liquid scintillators are a promising detector for high-resolution three-dimensional proton therapy dosimetry. Because the scintillator comprises both the active volume of the detector and the phantom material, an ideal scintillator will exhibit water equivalence in its radiological properties. One of the most fundamental of these is the scintillator’s stopping power. The objective of this study was to compare calculations and measurements of scintillator-to-water stopping power ratios to evaluate the suitability of the liquid scintillators BC-531 and OptiPhase HiSafe 3 for proton dosimetry. We also measured the relative scintillation output of the two scintillators. Both calculations and measurements show that the linear stopping power of OptiPhase is significantly closer to water than that of BC-531. BC-531 has a somewhat higher scintillation output. OptiPhase can be mixed with water at high concentrations, which further improves its scintillator-to-water stopping power ratio. However, this causes the solution to become cloudy, which has a negative impact on the scintillation output and spatial resolution of the detector. OptiPhase is preferred over BC-531 for proton dosimetry because its density and scintillator-to-water stopping power ratio are more water equivalent. PMID:25705066

Study on the Characteristics of a Scintillator for Beta-ray Detection using Epoxy Resin

NASA Astrophysics Data System (ADS)

Nam, Jong Soo; Choi, Yong Seok; Hong, Sang Bum; Seo, Bum Kyung; Moon, Jei Kwon; Choi, Jong Won

2017-09-01

A thin plate of a plastic scintillator for detecting a beta-ray was developed. The plastic scintillator was made using epoxy resin and organic scintillators such as 2.5-diphenyloxazole (PPO) and 1,4-bis [5-phenyl-2-oxazole] benzene (POPOP). The mixture ratio of epoxy resin and the organic scintillators was determined using their absorbance, transmittance, emission spectra, and transparency. Their optimal weight percentage of PPO and POPOP in the organic scintillators was adjusted to 0.2 wt%:0.01 wt%. The prepared plastic scintillator was used to measure the standard source of Sr-90. The pulse height spectra and total counts of the prepared plastic scintillator were similar to a commercial plastic scintillator. Based on the above results, a large-area plastic scintillator was prepared for rapid investigation of a site contaminated with Sr-90. The prepared large-area plastic scintillator was evaluated for the characteristics in the laboratory. The evaluation results are expected to be usefully utilized in the development of a large-area plastic scintillation detector. The large-area plastic scintillation detector developed on the basis of the evaluation results is expected to be utilized to quickly measure the contamination of Sr-90 in the grounds used as a nuclear power facility.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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.

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.

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

PubMed

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

2016-01-01

Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D-T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D-D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a discussion of the capabilities of the system and its outlook. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

PubMed

Brunner, S E; Schaart, D R

2017-06-07

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 mm 3 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.

Day and nighttime L-Band amplitude scintillations during low solar activity at a low latitude station in the South Pacific region

NASA Astrophysics Data System (ADS)

Prasad, Ramendra; Kumar, Sushil

2017-12-01

A morphological study of GPS L-band amplitude scintillations observed at a low latitude station, Suva (18.1°S, 178.4°E), Fiji, during low solar activity year 2010 of solar cycle 24, has been presented. Out of a total of 480 scintillation events recorded during 2010, 84.4% were weak (0.2 ≤ S4 < 0.3), 14.6% moderate (0.3 ≤ S4 < 0.45) and only 1% strong (0.45 ≤ S4). The amplitude scintillations were most pronounced in the local daytime with January registering the highest occurrence. Seasonal analysis revealed maximum scintillation occurrence during summer as compared to winter and equinox seasons. The daytime scintillation with a maximum in the summer is consistent with localized blanketing sporadic E observations and could also be possibly due to lightning activity around the observing station. Annual percentage occurrence shows that scintillations occurred mostly in the daytime with peak occurrence at around 05:00-09:00 LT. The daytime strong scintillation events were not associated with vTEC depletions and phase scintillations, but the signal to noise ratio during the scintillation events decreased with increase in scintillation index (S4). However, the post-midnight strong amplitude scintillations were associated with vTEC depletions and phase scintillations indicative of large scale irregularities (spread-F). The geomagnetic activity effect showed enhanced occurrence on geomagnetically disturbed days as compared to quite conditions. The geomagnetic storm effect on scintillations for 17 storms of different strengths (Dst ≤ 50 nT) during 2010-2011 showed an increase in the occurrence of post-storm scintillations, on the days following the storm.

Composite solid-state scintillators for neutron detection

DOEpatents

Dai, Sheng; Im, Hee-Jung; Pawel, Michelle D.

2006-09-12

Applicant's present invention is a composite scintillator for neutron detection comprising a matrix material fabricated from an inorganic sol-gel precursor solution homogeneously doped with a liquid scintillating material and a neutron absorbing material. The neutron absorbing material yields at least one of an electron, a proton, a triton, an alpha particle or a fission fragment when the neutron absorbing material absorbs a neutron. The composite scintillator further comprises a liquid scintillating material in a self-assembled micelle formation homogeneously doped in the matrix material through the formation of surfactant-silica composites. The scintillating material is provided to scintillate when traversed by at least one of an electron, a proton, a triton, an alpha particle or a fission fragment. The scintillating material is configured such that the matrix material surrounds the micelle formation of the scintillating material. The composite scintillator is fabricated and applied as a thin film on substrate surfaces, a coating on optical fibers or as a glass material.

Observational capabilities of solar satellite "Coronas-Photon"

NASA Astrophysics Data System (ADS)

Kotov, Yu.

Coronas-Photon mission is the third satellite of the Russian Coronas program on solar activity observation The main goal of the Coronas-Photon is the study of solar hard electromagnetic radiation in the wide energy range from UV up to high energy gamma-radiation sim 2000MeV Scientific payload for solar radiation observation consists of three type of instruments 1 monitors Natalya-2M Konus-RF RT-2 Penguin-M BRM Phoka Sphin-X Sokol for spectral and timing measurements of full solar disk radiation with timing in flare burst mode up to one msec Instruments Natalya-2M Konus-RF RT-2 will cover the wide energy range of hard X-rays and soft Gamma rays 15keV to 2000MeV and will together constitute the largest area detectors ever used for solar observations Detectors of gamma-ray monitors are based on structured inorganic scintillators with energy resolution sim 5 for nuclear gamma-line band to 35 for GeV-band PSD analysis is used for gamma neutron separation for solar neutron registration T 30MeV Penguin-M has capability to measure linear polarization of hard X-rays using azimuth are measured by Compton scattering asymmetry in case of polarization of an incident flux For X-ray and EUV monitors the scintillation phoswich detectors gas proportional counter CZT assembly and Filter-covered Si-diodes are used 2 Telescope-spectrometer TESIS for imaging solar spectroscopy in X-rays with angular resolution up to 1 in three spectral lines and RT-2 CZT assembly of CZT

Set of instruments for solar EUV and soft X-ray monitoring onboard satellite Coronas-Photon

NASA Astrophysics Data System (ADS)

Kotov, Yury; Kochemasov, Alexey; Kuzin, Sergey; Kuznetsov, Vladimir; Sylwester, Janusz; Yurov, Vitaly

Coronas-Photon mission is the third satellite of the Russian Coronas program on solar activity observation. The main goal of the "Coronas-Photon" is the study of solar hard electromagnetic radiation in the wide energy range from UV up to high energy gamma-radiation (2000MeV). Scientific payload for solar radiation observation consists of three types of instruments: Monitors (Natalya-2M, Konus-RF, RT-2, Penguin-M, BRM, PHOKA, Sphin-X, SOKOL spectral and timing measurements of full solar disk radiation have timing in flare/burst mode up to one msec. Instruments Natalya-2M, Konus-RF, RT-2 will cover the wide energy range of hard X-rays and soft gamma-rays (15keV to 2000MeV) and will together constitute the largest area detectors ever used for solar observations. Detectors of gamma-ray monitors are based on structured inorganic scintillators. For X-ray and EUV monitors the scintillation phoswich detectors, gas proportional counter, CdZnTe assembly and filter-covered Si-diodes are used. Telescope-spectrometer TESIS for imaging solar spectroscopy in X-rays has angular resolution up to 1arcsec in three spectral lines. Satellite platform and scientific payload is under construction to be launched in autumn 2008. Satellite orbit is circular with initial height 550km and inclination 82.5degrees. Accuracy of the spacecraft orientation to the Sun is better 3arcmin. In the report the capability of PHOKA, SphinX, SOKOL and TESIS as well as the observation program are described and discussed.

Rapid and simultaneous determination of Strontium-89 and Strontium-90 in seawater.

PubMed

Tayeb, Michelle; Dai, Xiongxin; Sdraulig, Sandra

2016-03-01

A rapid method has been developed for the direct determination of radiostrontium ((89)Sr and (90)Sr) released in seawater in the early phase of an accident. The method employs a fast and effective pre-concentration of radiostrontium by Sr-Ca co-precipitation followed by separation of radiostrontium using extraction chromatography technique. Radiostrontium is effectively separated in the presence of excessive dominant salts of seawater. Čerenkov and liquid scintillation assay (LSA) techniques are used to determine (89)Sr and (90)Sr. Sample preparation time is approximately 4 h for a set of 10 samples. The method was validated using spiked seawater samples at various activity ratios of (89)Sr:(90)Sr ranging from 1:10 to 9:1. The mean chemical recovery of Sr was 85 ± 3%. (90)Sr showed variable relative bias which enhanced with increasing ratio of (89)Sr:(90)Sr and was in the range ± 21%. The highest biases of (90)Sr determination were due to lower activity concentrations of (90)Sr and are regarded as acceptable in emergency situations with elevated levels of radiostrontium in the sample. The minimum detectable concentration (MDC) of (90)Sr and (89)Sr varied at different (89)Sr:(90)Sr ratios. For 0.1 L seawater and 15 min counting time on a low background Hidex liquid scintillation counter (LSC), the MDC of (90)Sr was in the range of 1.7-3.5 Bq L(-1) and MDC of (89)Sr was in the range 0.5-2.4 Bq L(-1). Copyright © 2016 Elsevier Ltd. All rights reserved.

Portable compton gamma-ray detection system

DOEpatents

Rowland, Mark S [Alamo, CA; Oldaker, Mark E [Pleasanton, CA

2008-03-04

A Compton scattered gamma-ray detector system. The system comprises a gamma-ray spectrometer and an annular array of individual scintillators. The scintillators are positioned so that they are arrayed around the gamma-ray spectrometer. The annular array of individual scintillators includes a first scintillator. A radiation shield is positioned around the first scintillator. A multi-channel analyzer is operatively connected to the gamma-ray spectrometer and the annular array of individual scintillators.

Real-time Scintillation Monitoring in Alaska from a Longitudinal Chain of ASTRA's SM-211 GPS TEC and Scintillation Receivers

NASA Astrophysics Data System (ADS)

Crowley, G.; Azeem, S. I.; Reynolds, A.; Santana, J.; Hampton, D. L.

2013-12-01

Amplitude and phase scintillation can cause serious difficulties for GPS receivers. Intense scintillation can cause loss of lock. High latitude studies generally show that phase scintillation can be severe, but the amplitude scintillation tends to be small. The reason for this is not yet understood. Furthermore, the actual causes of the ionospheric irregularities that produce high latitude scintillation are not well understood. While the gradient drift instability is thought to be important in the F-region, there may be other structures present in either the E- or F-regions. The role of particle precipitation is also not well understood. Four of ASTRA's CASES GPS receivers were deployed in Alaska to demonstrate our ability to map scintillation in realtime, to provide space weather services to GPS users, and to initiate a detailed investigation of these effects. These dual-frequency GPS receivers measure total electron content (TEC) and scintillation. The scintillation monitors were deployed in a longitudinal chain at sites in Kaktovic, Fort Yukon, Poker Flat, and Gakona. Scintillation statistics show phase scintillations to be largest at Kaktovic and smallest at Gakona. We present GPS phase scintillation and auroral emission results from the Alaska chain to characterize the correspondence between scintillation and auroral features, and to investigate the role of high latitude auroral features in driving the phase scintillations. We will also present data showing how phase scintillation can cause other GPS receivers to lose lock. The data and results are particularly valuable because they illustrate some of the challenges of using GPS systems for positioning and navigation in an auroral region like Alaska. These challenges for snowplough drivers were recently highlighted, along with the CASES SM-211 space weather monitor, in a special video in which ASTRA and three other small businesses were presented with an entrepreneurial award from William Shatner (http://youtu.be/bIVKEQH_YPk).

Spectrometric measurements of radioisotope activity in the thyroid

NASA Astrophysics Data System (ADS)

Osko, Jakub; Golnik, Natalia

2008-01-01

The results of measurements of iodine 131I and technetium 99mTc uptake in human thyroid, performed with scintillation or semiconductor detectors can exhibit a considerable uncertainty due to the differences in the thyroid position in the patient's neck. Basic physical laws of radiation attenuation and scattering show that the final shape of the registered spectrum should depends on the thyroid position in the neck and on the thickness of the tissue between the thyroid and the detector. The use of the spectrometric measuring method is proposed in this work for determination of the iodine gathering effective depth. The performed studies showed that the measurements results can be used for improving the accuracy of the iodine 131I activity in thyroid measurements and for selection of the group of patients for whom the anatomical position of the thyroid or the spatial distribution of the iodine gathering is much different than the standard one, assumed during the calibration of the counters. The results of the measurements were in agreement with Monte-Carlo calculations of the detector response. The method was used in routine monitoring of occupationally exposed persons, using the thyroid counter. A group of six persons with measurable internal contamination was selected and the measurements were performed on consecutive days, so the results could be registered at decreasing iodine activities in the thyroid. Larger series of measurements were performed at Brodno Regional Hospital in Warsaw, for a group of 95 patients after diagnostic administration of iodine 131I.

[Cost-benefit of the Schilling test using cobalt-57].

PubMed

Arteaga de Murphy, C; Maisterrena, J; Labardini, J; Ruiz, A; Luviano, C

1991-01-01

Our purpose in the present publication is to determine the cost-benefit relation of the Schilling test used to measure the intestinal absorption of radioactive vitamin B12. The 60Co-B12 urinary excretion Schilling test was first reported in 1953, and five years later it was being performed at the National Institute of Nutrition (INNSZ) in Mexico City. It was performed in its original version until 1969 and from 1970 to 1980, the direct absorption was measured with a whole-body counter. For the last nine years we have used the Schilling test with 57Co labeled cyanocobalamin. From January 1981 through March 1990, 240 of these tests were carried out in 120 patients. The results were tabulated and compared with their clinical diagnosis. We analyzed our laboratory and labor costs. An oral dose of 0.5 micrograms of vitamin B12 labelled with 18.5 Bq of 57Co is taken by the fasting patients and two hours later one mg of standard B12 vitamin is injected. Urine is collected for 48 hours and the radioactivity is measured in a scintillation counter. Three days later the test is repeated with an additional oral dose of intrinsic factor (IF). The total expense is calculated using the following factors: the cost of the imported radioactive vitamin, IF capsules, parenteral B12 vitamin, syringes, equipment use and its depreciation, laboratory material, and salaries for the professional and administrative personnel.(ABSTRACT TRUNCATED AT 250 WORDS)

Radioactive contamination of scintillators

NASA Astrophysics Data System (ADS)

Danevich, F. A.; Tretyak, V. I.

2018-03-01

Low counting experiments (search for double β decay and dark matter particles, measurements of neutrino fluxes from different sources, search for hypothetical nuclear and subnuclear processes, low background α, β, γ spectrometry) require extremely low background of a detector. Scintillators are widely used to search for rare events both as conventional scintillation detectors and as cryogenic scintillating bolometers. Radioactive contamination of a scintillation material plays a key role to reach low level of background. Origin and nature of radioactive contamination of scintillators, experimental methods and results are reviewed. A programme to develop radiopure crystal scintillators for low counting experiments is discussed briefly.

Inorganic scintillating materials and scintillation detectors

PubMed Central

YANAGIDA, Takayuki

2018-01-01

Scintillation materials and detectors that are used in many applications, such as medical imaging, security, oil-logging, high energy physics and non-destructive inspection, are reviewed. The fundamental physics understood today is explained, and common scintillators and scintillation detectors are introduced. The properties explained here are light yield, energy non-proportionality, emission wavelength, energy resolution, decay time, effective atomic number and timing resolution. For further understanding, the emission mechanisms of scintillator materials are also introduced. Furthermore, unresolved problems in scintillation phenomenon are considered, and my recent interpretations are discussed. These topics include positive hysteresis, the co-doping of non-luminescent ions, the introduction of an aimed impurity phase, the excitation density effect and the complementary relationship between scintillators and storage phosphors. PMID:29434081

Characteristics of High Latitude Ionosphere Scintillations

NASA Astrophysics Data System (ADS)

Morton, Y.

2012-12-01

As we enter a new solar maximum period, global navigation satellite systems (GNSS) receivers, especially the ones operating in high latitude and equatorial regions, are facing an increasing threat from ionosphere scintillations. The increased solar activities, however, also offer a great opportunity to collect scintillation data to characterize scintillation signal parameters and ionosphere irregularities. While there are numerous GPS receivers deployed around the globe to monitor ionosphere scintillations, most of them are commercial receivers whose signal processing mechanisms are not designed to operate under ionosphere scintillation. As a result, they may distort scintillation signal parameters or lose lock of satellite signals under strong scintillations. Since 2008, we have established and continuously improved a unique GNSS receiver array at HAARP, Alaska. The array contains high ends commercial receivers and custom RF front ends which can be automatically triggered to collect high quality GPS and GLONASS satellite signals during controlled heating experiments and natural scintillation events. Custom designed receiver signal tracking algorithms aim to preserve true scintillation signatures are used to process the raw RF samples. Signal strength, carrier phase, and relative TEC measurements generated by the receiver array since its inception have been analyzed to characterize high latitude scintillation phenomena. Daily, seasonal, and solar events dependency of scintillation occurrence, spectral contents of scintillation activities, and plasma drifts derived from these measurements will be presented. These interesting results demonstrate the feasibility and effectiveness of our experimental data collection system in providing insightful details of ionosphere responses to active perturbations and natural disturbances.

Bright Lu2O3:Eu thin-film scintillators for high-resolution radioluminescence microscopy

PubMed Central

Sengupta, Debanti; Miller, Stuart; Marton, Zsolt; Chin, Frederick; Nagarkar, Vivek

2015-01-01

We investigate the performance of a new thin-film Lu2O3:Eu scintillator for single-cell radionuclide imaging. Imaging the metabolic properties of heterogeneous cell populations in real time is an important challenge with clinical implications. We have developed an innovative technique called radioluminescence microscopy, to quantitatively and sensitively measure radionuclide uptake in single cells. The most important component of this technique is the scintillator, which converts the energy released during radioactive decay into luminescent signals. The sensitivity and spatial resolution of the imaging system depend critically on the characteristics of the scintillator, i.e. the material used and its geometrical configuration. Scintillators fabricated using conventional methods are relatively thick, and therefore do not provide optimal spatial resolution. We compare a thin-film Lu2O3:Eu scintillator to a conventional 500 μm thick CdWO4 scintillator for radioluminescence imaging. Despite its thinness, the unique scintillation properties of the Lu2O3:Eu scintillator allow us to capture single positron decays with over fourfold higher sensitivity, a significant achievement. The thin-film Lu2O3:Eu scintillators also yield radioluminescence images where individual cells appear smaller and better resolved on average than with the CdWO4 scintillators. Coupled with the thin-film scintillator technology, radioluminescence microscopy can yield valuable and clinically relevant data on the metabolism of single cells. PMID:26183115

X-ray detection properties of plastic scintillators containing surface-modified Bi2O3 nanoparticles

NASA Astrophysics Data System (ADS)

Hiyama, Fumiyuki; Noguchi, Takio; Koshimizu, Masanori; Kishimoto, Shunji; Haruki, Rie; Nishikido, Fumihiko; Fujimoto, Yutaka; Aida, Tsutomu; Takami, Seiichi; Adschiri, Tadafumi; Asai, Keisuke

2018-05-01

Plastic scintillators containing Bi2O3 nanoparticles (NPs) were developed as detectors for X-ray synchrotron radiation. A hydrothermal method was used to synthesize the NPs that had average particle sizes of less than 10 nm. Higher NP concentration led to a higher detection efficiency at 67.4 keV. The light yield of the scintillator containing 5 wt % Bi2O3 NPs was comparable with or higher than that of the commercially available plastic scintillator, EJ 256. The time resolution of the developed scintillation detector equipped with each sample scintillator was approximately 0.6 ns. Dispersion of nanoparticles within plastic scintillators is generally applicable and has wide application as a method for preparation of plastic scintillators for detecting X-ray synchrotron radiation.

GAGG:ce single crystalline films: New perspective scintillators for electron detection in SEM.

PubMed

Bok, Jan; Lalinský, Ondřej; Hanuš, Martin; Onderišinová, Zuzana; Kelar, Jakub; Kučera, Miroslav

2016-04-01

Single crystal scintillators are frequently used for electron detection in scanning electron microscopy (SEM). We report gadolinium aluminum gallium garnet (GAGG:Ce) single crystalline films as a new perspective scintillators for the SEM. For the first time, the epitaxial garnet films were used in a practical application: the GAGG:Ce scintillator was incorporated into a SEM scintillation electron detector and it showed improved image quality. In order to prove the GAGG:Ce quality accurately, the scintillation properties were examined using electron beam excitation and compared with frequently used scintillators in the SEM. The results demonstrate excellent emission efficiency of the GAGG:Ce single crystalline films together with their very fast scintillation decay useful for demanding SEM applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Microdome-gooved Gd(2)O(2)S:Tb scintillator for flexible and high resolution digital radiography.

PubMed

Jung, Phill Gu; Lee, Chi Hoon; Bae, Kong Myeong; Lee, Jae Min; Lee, Sang Min; Lim, Chang Hwy; Yun, Seungman; Kim, Ho Kyung; Ko, Jong Soo

2010-07-05

A flexible microdome-grooved Gd(2)O(2)S:Tb scintillator is simulated, fabricated, and characterized for digital radiography applications. According to Monte Carlo simulation results, the dome-grooved structure has a high spatial resolution, which is verified by X-ray image performance of the scintillator. The proposed scintillator has lower X-ray sensitivity than a nonstructured scintillator but almost two times higher spatial resolution at high spatial frequency. Through evaluation of the X-ray performance of the fabricated scintillators, we confirm that the microdome-grooved scintillator can be applied to next-generation flexible digital radiography systems requiring high spatial resolution.

Ionosphere scintillations associated with features of equatorial ionosphere

NASA Technical Reports Server (NTRS)

Chandra, H.; Vats, H. O.; Sethia, G.; Deshpande, M. R.; Rastogi, R. G.; Sastri, J. H.; Murthy, B. S.

1979-01-01

Amplitude scintillations of radio beacons aboard the ATS-6 satellite on 40 MHz, 140 MHz and 360 MHz recorded during the ATS-6 phase II at an equatorial station Ootacamund (dip 4 deg N) and the ionograms at a nearby station Kodaikanal (dip 3.5 deg N) are examined for scintillation activity. Only sporadic E events, other than Es-q, Es-c or normal E are found to be associated with intense daytime scintillations. Scintillations are also observed during night Es conditions. The amplitude spread is associated with strong scintillations on all frequencies while frequency spread causes weaker scintillations and that mainly at 40 MHz.

Characterization of scintillator-based detectors for few-ten-keV high-spatial-resolution x-ray imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larsson, Jakob C., E-mail: jakob.larsson@biox.kth.se; Lundström, Ulf; Hertz, Hans M.

2016-06-15

Purpose: High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scintillator-based detectors for this energy range and at high spatial frequencies. Methods: The authors determine the modulation transfer function, noise power spectrum (NPS), and detective quantum efficiency for Gadox, needle CsI, and structured CsI scintillators of different thicknesses and at different photon energies. An extended analysis of the NPS allows for direct measurements of the scintillator effective absorption efficiency andmore » effective light yield as well as providing an alternative method to assess the underlying factors behind the detector properties. Results: There is a substantial difference in performance between the scintillators depending on the imaging task but in general, the CsI based scintillators perform better than the Gadox scintillators. At low energies (16 keV), a thin needle CsI scintillator has the best performance at all frequencies. At higher energies (28–38 keV), the thicker needle CsI scintillators and the structured CsI scintillator all have very good performance. The needle CsI scintillators have higher absorption efficiencies but the structured CsI scintillator has higher resolution. Conclusions: The choice of scintillator is greatly dependent on the imaging task. The presented comparison and methodology will assist the imaging scientist in optimizing their high-resolution few-ten-keV imaging system for best performance.« less

Characterization of scintillator-based detectors for few-ten-keV high-spatial-resolution x-ray imaging.

PubMed

Larsson, Jakob C; Lundström, Ulf; Hertz, Hans M

2016-06-01

High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scintillator-based detectors for this energy range and at high spatial frequencies. The authors determine the modulation transfer function, noise power spectrum (NPS), and detective quantum efficiency for Gadox, needle CsI, and structured CsI scintillators of different thicknesses and at different photon energies. An extended analysis of the NPS allows for direct measurements of the scintillator effective absorption efficiency and effective light yield as well as providing an alternative method to assess the underlying factors behind the detector properties. There is a substantial difference in performance between the scintillators depending on the imaging task but in general, the CsI based scintillators perform better than the Gadox scintillators. At low energies (16 keV), a thin needle CsI scintillator has the best performance at all frequencies. At higher energies (28-38 keV), the thicker needle CsI scintillators and the structured CsI scintillator all have very good performance. The needle CsI scintillators have higher absorption efficiencies but the structured CsI scintillator has higher resolution. The choice of scintillator is greatly dependent on the imaging task. The presented comparison and methodology will assist the imaging scientist in optimizing their high-resolution few-ten-keV imaging system for best performance.

Cherenkov and scintillation light separation on the CheSS experiment

NASA Astrophysics Data System (ADS)

Caravaca, Javier; Land, Benjamin; Descamps, Freija; Orebi Gann, Gabriel D.

2016-09-01

Separation of the scintillation and Cherenkov light produced in liquid scintillators enables outstanding capabilities for future particle detectors, the most relevant being: particle directionality information in a low energy threshold detector and improved particle identification. The CheSS experiment uses an array of small, fast photomultipliers (PMTs) and state-of-the-art electronics to demonstrate the reconstruction of a Cherenkov ring in liquid scintillator using two techniques: based on the photon density and using the photon hit time information. A charged particle ionizing a scintillation medium produces a prompt Cherenkov cone and late isotropic scintillation light, typically delayed by several ns. The fast response of our PMTs and DAQ provides a precision well below the ns level, making possible the time separation. Furthermore, the usage of the new developed water-based liquid scintillators (WbLS) enhances the separation since it allows tuning of the Cherenkov/Scintillation ratio. Latest results on the separation for pure liquid scintillators and WbLS will be presented.

Plastic Organic Scintillator Chemistry

NASA Astrophysics Data System (ADS)

Brightwell, C. R.; Temanson, E. S.; Febbraro, M. T.

2017-09-01

Due to their high light output, quick decay time, affordability, durability and ability to be molded, plastic organic scintillators are increasingly becoming a more viable method of particle detection. Since the plastic is composed entirely of single molecular chains with repeating units, scintillating properties remain stable despite changes in experimental conditions. Different scintillating plastics can be modified and tailored to suit specific experiments depending on a variety of requirements such as light output, scintillating wavelength, and PMT compatibility. The synthesis chemistry of a recent but well-known scintillating polyester, polyethylene naphthalate (PEN) will be presented to demonstrate how plastic organic scintillators can be modified for different particle detection experiments. PEN has been successfully synthesized at ORNL, and procedures are currently being investigated to modify PEN using different reactants and catalysts. The goal is to achieve a transparent scintillating plastic with an incorporated wavelength shifter in the chain that scintillates with a wavelength around 440 nm. The status of this project will be presented. This research is supported by the U. S. Department of Energy Office of Science.

Scintillation analysis of truncated Bessel beams via numerical turbulence propagation simulation.

PubMed

Eyyuboğlu, Halil T; Voelz, David; Xiao, Xifeng

2013-11-20

Scintillation aspects of truncated Bessel beams propagated through atmospheric turbulence are investigated using a numerical wave optics random phase screen simulation method. On-axis, aperture averaged scintillation and scintillation relative to a classical Gaussian beam of equal source power and scintillation per unit received power are evaluated. It is found that in almost all circumstances studied, the zeroth-order Bessel beam will deliver the lowest scintillation. Low aperture averaged scintillation levels are also observed for the fourth-order Bessel beam truncated by a narrower source window. When assessed relative to the scintillation of a Gaussian beam of equal source power, Bessel beams generally have less scintillation, particularly at small receiver aperture sizes and small beam orders. Upon including in this relative performance measure the criteria of per unit received power, this advantageous position of Bessel beams mostly disappears, but zeroth- and first-order Bessel beams continue to offer some advantage for relatively smaller aperture sizes, larger source powers, larger source plane dimensions, and intermediate propagation lengths.

Gamma ray spectroscopy employing divalent europium-doped alkaline earth halides and digital readout for accurate histogramming

DOEpatents

Cherepy, Nerine Jane; Payne, Stephen Anthony; Drury, Owen B.; Sturm, Benjamin W.

2016-02-09

According to one embodiment, a scintillator radiation detector system includes a scintillator, and a processing device for processing pulse traces corresponding to light pulses from the scintillator, where the processing device is configured to: process each pulse trace over at least two temporal windows and to use pulse digitization to improve energy resolution of the system. According to another embodiment, a scintillator radiation detector system includes a processing device configured to: fit digitized scintillation waveforms to an algorithm, perform a direct integration of fit parameters, process multiple integration windows for each digitized scintillation waveform to determine a correction factor, and apply the correction factor to each digitized scintillation waveform.

Optical and Scintillation Properties of Polydimethyl-Diphenylsiloxane Based Organic Scintillators

NASA Astrophysics Data System (ADS)

Quaranta, Alberto; Carturan, Sara Maria; Marchi, Tommaso; Kravchuk, Vladimir L.; Gramegna, Fabiana; Maggioni, Gianluigi; Degerlier, Meltem

2010-04-01

Polysiloxane based scintillators with high light yield have been synthesized. The polymer consists in cross-linked polydimethyl-co-diphenylsiloxane with different molar percentages of phenyl units. 2,5-diphenyl oxazole (PPO) and 2,5-bis(5-ter-butyl-2-benzoxazolyl)thiophene (BBOT) have been dispersed in the polymer as dopants. The energy transfer and scintillation capabilities have been investigated, for two different amounts of phenyl groups in the polymer network and for different concentrations of dye molecules, by means of fluorescence spectroscopy, ion beam induced luminescence (IBIL) and scintillation yield measurements with ¿ particles from an 241Am source. The luminescence features and the scintillation yields have been correlated to the composition of the scintillators.

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.

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.

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.

Study of a coincident observation between the ROCSAT-1 density irregularity and Ascension Island scintillation

NASA Astrophysics Data System (ADS)

Liu, Y. H.; Chao, C. K.; Su, S.-Y.; Liu, C. H.

2012-10-01

A coincident observation that occurred on 24 March 2000 between the irregularity structure measured by ROCSAT-1 and the scintillation experiment at the Ascension Island has been studied. The study of scintillation statistics is carried out first, and the results show that the Nakagami distribution can portray the normalized intensity of the L-band scintillation at various S4 values, up to S4 equal to 1.4. Moreover, the departure of frequency dependence on S4 predicted by the weak scintillation is noticed due to multiple forward scattering effects. The coincident feature between the characteristics of irregularity structure and the scintillation variation are then studied. The causal relationship between the fluctuation of ion density and the scintillation variation is obtained. A numerical simulation using the parabolic wave equation has been carried out with the ROCSAT-1 data in space to compare with the ground scintillation observation. The results show the reasonable scintillation level at the coincident time to indicate a direct relationship between the irregularity structure and the scintillation in both temporal and amplitudinal variations. Finally, some assumptions and limitations of the simulation model are discussed.

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.

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.

Seasonal ionospheric scintillation analysis during increasing solar activity at mid-latitude

NASA Astrophysics Data System (ADS)

Ahmed, Wasiu Akande; Wu, Falin; Agbaje, Ganiyu Ishola; Ednofri, Ednofri; Marlia, Dessi; Zhao, Yan

2017-09-01

Monitoring of ionospheric parameters (such as Total Electron Content and scintillation) is of great importance as it affects and contributes to the errors encountered by radio signals. It thus requires constant measurements to avoid disastrous situation for space agencies, parastatals and departments that employ GNSS applications in their daily operations. The research objective is to have a better understanding of the behaviour of ionospheric scintillation at midlatitude as it threatens the performances of satellite communication, navigation systems and military operations. This paper adopts seasonal ionospheric scintillation scenario. The mid-latitude investigation of ionospheric effect of scintillation was conducted during the increasing solar activity from 2011-2015. Ionospheric scintillation data were obtained from four ionospheric monitoring stations located at mid-latitude (i.e Shenzhen North Station, Beijing Changping North Station Branch, Beijing North Station and Beijing Miyun ground Station). The data was collected from January 2011 to December 2015. There were absence of data due to software problem or system failure at some locations. The scintillation phenomenon was computed using Global Ionospheric Scintillation and TEC Monitoring Model. There are four seasons which existed in China namely: Spring, Summer, Autumn and Winter. The relationship between TEC, amplitude and phase scintillation were observed for each of these seasons. The results indicated that the weak amplitude scintillation was observed as against phase scintillation which was high. Phase scintillation was gradually enhanced from 2011 to 2012 and later declined till 2014. TEC was also at peak around 00:00-10:00 UT (08:00-18:00 LT). The seasonal events temporal density characteristics comply with solar cycle prediction as such it ascended from 2011 to 2013 and then scintillation parameters declined significantly afterwards.

Comparisons of COSMIC and C/NOFS GPS Occultation Ionospheric Scintillation Measurements with Ground-based Radar and VHF Measurements

NASA Astrophysics Data System (ADS)

Ruggiero, F. H.; Groves, K. M.; Straus, P. R.; Caton, R. G.; Starks, M. J.; Tanyi, K. L.; Verlinden, M.

2009-12-01

Ionospheric irregularities are known to cause scintillation of trans-ionospheric radio signals and can affect space-based UHF/VHF communications, causing outages, and degrading GPS accuracy and precision. Current capability for characterizing and predicting ionospheric scintillation utilizes a network of ground-based receivers to detect scintillation and then extrapolate for short-term forecasts. Practical limits on deploying the ground receivers limits the accuracy and spatial coverage one can achieve with this approach. A more global approach is to use a set of space-based satellites equipped with GPS receivers, such as the COSMIC satellite constellation, to measure scintillations observed during so-called occultations with GPS satellites. In this paper the signal-to-noise values of GPS L1 signals received on the COSMIC and C/NOFS satellites for the portions of the occultations that are not affected by the terrestrial atmosphere are examined to help identify areas of ionospheric scintillation. Three years of S4 scintillation index values from COSMIC occultations are compared with near-zenith ground-based VHF S4 scintillation measurements from the AFRL SCIntillation Network Decision Aid (SCINDA) network stations. The data are correlated to ascertain the viability of using space-based scintillation measurements to characterize and predict scintillation to ground-based receivers. Several days of COSMIC and C/NOFS data are compared with each other and the ALTAIR radar located on Kwajalein Atoll, Marshall Islands to examine how occultation geometry affects observed scintillation and also to verify techniques that provide an upper bound on the spatial location of the ionospheric irregularities contributing to scintillations observed in the occultations.

Validating the use of scintillation proxies to study ionospheric scintillation over the Ugandan region

NASA Astrophysics Data System (ADS)

Amabayo, Emirant B.; Jurua, Edward; Cilliers, Pierre J.

2015-06-01

In this study, we compare the standard scintillation indices (S4 and σΦ) from a SCINDA receiver with scintillation proxies (S4p and | sDPR |) derived from two IGS GPS receivers. Amplitude (S4) and phase (σΦ) scintillation data were obtained from the SCINDA installed at Makerere University (0.34°N, 32.57°E). The corresponding amplitude (S4p) and phase (| sDPR |) scintillation proxies were derived from data archived by IGS GPS receivers installed at Entebbe (0.04°N, 32.44°E) and Mbarara (0.60°S, 30.74°E). The results show that for most of the cases analysed in this study, σΦ and | sDPR | are in agreement. Amplitude scintillation occurrence estimated using the S4p are fairly consistent with the standard S4, mainly between 17:00 UT and 21:00 UT, despite a few cases of over and under estimation of scintillation levels by S4p. Correlation coefficients between σΦ and the | sDPR | proxy revealed positive correlation. Generally, S4p and S4 exhibits both moderate and strong positive correlation. TEC depletions associated with equatorial plasma bubbles are proposed as the cause of the observed scintillation over the region. These equatorial plasma bubbles were evident along the ray paths to satellites with PRN 2, 15, 27 and 11 as observed from MBAR and EBBE. In addition to equatorial plasma bubbles, atmospheric gravity waves with periods similar to those of large scale traveling ionospheric disturbances were also observed as one of the mechanisms for scintillation occurrence. The outcome of this study implies that GPS derived scintillation proxies can be used to quantify scintillation levels in the absence of standard scintillation data in the equatorial regions.

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.

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.

Use of a large time-compensated scintillation detector in neutron time-of-flight measurements

DOEpatents

Goodman, Charles D.

1979-01-01

A scintillator for neutron time-of-flight measurements is positioned at a desired angle with respect to the neutron beam, and as a function of the energy thereof, such that the sum of the transit times of the neutrons and photons in the scintillator are substantially independent of the points of scintillations within the scintillator. Extrapolated zero timing is employed rather than the usual constant fraction timing. As a result, a substantially larger scintillator can be employed that substantially increases the data rate and shortens the experiment time.

Plastic scintillators with efficient neutron/gamma pulse shape discrimination

NASA Astrophysics Data System (ADS)

Zaitseva, Natalia; Rupert, Benjamin L.; PaweŁczak, Iwona; Glenn, Andrew; Martinez, H. Paul; Carman, Leslie; Faust, Michelle; Cherepy, Nerine; Payne, Stephen

2012-03-01

A possibility of manufacturing plastic scintillators with efficient neutron/gamma pulse shape discrimination (PSD) is demonstrated using a system of a polyvinyltoluene (PVT) polymer matrix loaded with a scintillating dye, 2,5-diphenyloxazole (PPO). Similarities and differences of conditions leading to the rise of PSD in liquid and solid organic scintillators are discussed based on the classical model of excited state interaction and delayed light formation. First characterization results are presented to show that PSD in plastic scintillators can be of the similar magnitude or even higher than in standard commercial liquid scintillators.

Light propagation and fluorescence quantum yields in liquid scintillators

NASA Astrophysics Data System (ADS)

Buck, C.; Gramlich, B.; Wagner, S.

2015-09-01

For the simulation of the scintillation and Cherenkov light propagation in large liquid scintillator detectors a detailed knowledge about the absorption and emission spectra of the scintillator molecules is mandatory. Furthermore reemission probabilities and quantum yields of the scintillator components influence the light propagation inside the liquid. Absorption and emission properties are presented for liquid scintillators using 2,5-Diphenyloxazole (PPO) and 4-bis-(2-Methylstyryl)benzene (bis-MSB) as primary and secondary wavelength shifter. New measurements of the quantum yields for various aromatic molecules are shown.

Liquid Scintillator Production for the NOvA Experiment

DOE PAGES

Mufson, S.; Baugh, B.; Bower, C.; ...

2015-04-15

The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator as the active detector medium to its near and far detectors. The composition of this scintillator was specifically developed to satisfy NOvA's performance requirements. A rigorous set of quality control procedures was put in place to verify that the incoming components and the blended scintillator met these requirements. The scintillator was blended commercially in Hammond, IN. The scintillator was shipped to the NOvA detectors using dedicated stainless steel tanker trailers cleaned to food grade.

25 years of satellite beacon studies in Japan

NASA Astrophysics Data System (ADS)

Sinno, K.

The occurrence of ionospheric scintillation exhibits behavior similar to both that of TEC fluctuations and night time ionospheric spread-F. The scintillations are also noted to vary in the same fashion diurnally and seasonally, having a principal maximum at about midnight during the summer. These characteristics also apply to the 1.7 GHz scintillation detected by the ETS-II and GMS satellites. Attention is presently given to the scintillation's frequency dependence, the development of severe scintillation events, and the enhancement of midlatitude scintillation due to field-aligned irregularities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nusrat, H; Pang, G; Sarfehnia, A

Purpose: This work seeks to develop a beam quality meter using multiple differently doped plastic scintillators that are thus intrinsically beam-quality dependent. Plastic scintillators spontaneously emit visible light upon irradiation; the amount of light produced is dependent on stopping power (closely related to LET) according to Birks’ law. Doping plastic scintillators can be used to tune their sensitivity to specific LET ranges. Methods: GEANT4.10.1 Monte Carlo (MC) was used to evaluate the response of various scintillator dopant combinations. MC radiation transport and scintillator light response were validated against previously published literature. Current work involves evaluating detector response experimentally; to thatmore » end, a detector prototype with interchangeable scintillator housing was constructed. Measurement set-up guides light emitted by the scintillator to a photomultiplier tube via a glass taper junction coupled to an optical fiber. The resulting signal is measured by an electrometer, and normalized to dose readout from a diode. Measurements have been done using clinical electron and orthovoltage beams. MC response (simulated scintillator light normalized to dose scored inside the scintillating volume) was evaluated for four different LET radiations for an undoped and 1%Pb doped scintillator (σ=0.85%). Simulated incident electrons included: 0.05, 0.1, 0.2, 6, 12, and 18 MeV; these energies correspond to a range of stopping power (related to LET) values ranging from 1.824 to 11.09 MeVcm{sup 2}g{sup −1} (SCOL from NIST-ESTAR). Results: Initial MC results show a distinct divergence in scintillator response as LET increases. The response for undoped plastic scintillator indicated a 35.0% increase in signal when going from 18 MeV (low LET) to 0.05 MeV (high LET) while 1%-Pb doped scintillator indicated a 100.9% increase. Conclusion: After validating MC against measurement, simulations will be used to test various concentrations (2%, 4%, 6%) of different high-Z material dopants (W, Mo) to optimize the scintillator types for the beam quality meter. NSERC Discovery Grant RGPIN-435608.« less

Construction of monoenergetic neutron calibration fields using 45Sc(p, n)45Ti reaction at JAEA.

PubMed

Tanimura, Y; Saegusa, J; Shikaze, Y; Tsutsumi, M; Shimizu, S; Yoshizawa, M

2007-01-01

The 8 and 27 keV monoenergetic neutron calibration fields have been developed by using (45)Sc(p, n)(45)Ti reaction. Protons from a 4-MV Pelletron accelerator are used to bombard a thin scandium target evaporated onto a platinum disc. The proton energies are finely adjusted to the resonance to generate the 8 and 27 keV neutrons by applying a high voltage to the target assemblies. The neutron energies were measured using the time-of-flight method with a lithium glass scintillation detector. The neutron fluences at a calibration point located at 50 cm from the target were evaluated using Bonner spheres. A long counter was placed at 2.2 m from the target and at 60 degrees to the direction of the proton beam in order to monitor the fluence at the calibration point. Fluence and dose equivalent rates at the calibration point are sufficient to calibrate many types of the neutron survey metres.

Measurement of the proton $$A_1$$ and $$A_2$$ spin asymmetries. Probing Color Forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Whitney

The Spin Asymmetries of the Nucleon Experiment (SANE) measured the proton spin structure functionmore » $$g_2$$ in a range of Bjorken x, 0.3 < x < 0.8, where extraction of the twist-3 matrix element $$d_2^p$$ (an integral of $$g_2$$ weighted by $x^2$) is most sensitive. The data was taken from $Q^2$ equal to 2.5 $GeV^2$ up to 6.5 $GeV^2$. In this polarized electron scattering off a polarized hydrogen target experiment, two double spin asymmetries, A∥ and A⊥ were measured using the BETA (Big Electron Telescope Array) Detector. BETA consisted of a scintillator hodoscope, gas Cerenkov counter, lucite hodoscope and a large lead glass electromagnetic calorimeter. With a unique open geometry, a threshold gas Cerenkov detector allowed BETA to cleanly identify electrons for this inclusive experiment. A measurement of $$d_2^p$$ is compared to lattice QCD calculations.« less

Cosmic Radiation Detection and Observations

NASA Astrophysics Data System (ADS)

Ramirez Chavez, Juan; Troncoso, Maria

Cosmic rays consist of high-energy particles accelerated from remote supernova remnant explosions and travel vast distances throughout the universe. Upon arriving at earth, the majority of these particles ionize gases in the upper atmosphere, while others interact with gas molecules in the troposphere and producing secondary cosmic rays, which are the main focus of this research. To observe these secondary cosmic rays, a detector telescope was designed and equipped with two silicon photomultipliers (SiPMs). Each SiPM is coupled to a bundle of 4 wavelength shifting optical fibers that are embedded inside a plastic scintillator sheet. The SiPM signals were amplified using a fast preamplifier with coincidence between detectors established using a binary logic gate. The coincidence events were recorded with two devices; a digital counter and an Arduino micro-controller. For detailed analysis of the SiPM waveforms, a DRS4 sensory digitizer captured the waveforms for offline analysis with the CERN software package Physics Analysis Workstation in a Linux environment. Results from our experiments would be presented. Hartnell College STEM Internship Program.

Small-angle fragmentation of carbon ions at 0.6 GeV/n: A comparison with models of ion-ion interactions

DOE PAGES

Krutenkova, A. P.; Abramov, B. M.; Alekseev, P. N.; ...

2015-05-29

Momentum distributions of hydrogen and helium isotopes from ¹²C fragmentation at 3.5° were measured at 0.6 GeV/nucleon in the FRAGM experiment at ITEP TWA heavy ion accelerator. The fragments were selected by correlated time of flight and dE/dx measurements with a magnetic spectrometer with scintillation counters. The main attention was drawn to the high momentum region where the fragment velocity exceeds the velocity of the projectile nucleus. The momentum spectra of fragments span the region of the fragmentation peak as well as the cumulative region. The differential cross sections cover six orders of magnitude. The distributions measured are compared tomore » the predictions of three ion-ion interaction models: BC, QMD and LAQGSM03.03. The kinetic energy spectra of fragments in the projectile rest frame have an exponential shape with two temperatures, being defined by their slope parameters.« less

Small-angle fragmentation of carbon ions at 0.6 GeV/n. A comparison with models of ion-ion interactions

DOE PAGES

Krutenkova, Anna P.; Abramov, B. M.; Alekseev, P. N.; ...

2015-05-29

The momentum distributions of hydrogen and helium isotopes from 12C fragmentation at 3.5° were measured at 0.6 GeV/nucleon in the FRAGM experiment at ITEP TWA heavy ion accelerator. The fragments were selected by correlated time of flight and dE/dx measurements with a magnetic spectrometer with scintillation counters. The main attention was drawn to the high momentum region where the fragment velocity exceeds the velocity of the projectile nucleus. The momentum spectra of fragments span the region of the fragmentation peak as well as the cumulative region. Moreover, the differential cross sections cover six orders of magnitude. The distributions measured aremore » compared to the predictions of three ion-ion interaction models: BC, QMD and LAQGSM03.03. The kinetic energy spectra of fragments in the projectile rest frame have an exponential shape with two temperatures, being defined by their slope parameters.« less

Performance of the STAR Event Plane Detector

NASA Astrophysics Data System (ADS)

Ewigleben, Justin; Justin Ewigleben Collaboration

2017-09-01

The Beam Energy Scan (BES) program at the Relativistic Heavy-Ion Collider has shown hints of a critical point and first order phase transition at the BES energies. Key measurements for locating the critical point and determining the first order phase transition are limited by poor event plane resolution, limited statistics and a TPC-only centrality determination. A new event plane and collision centrality detector (EPD) is planned to replace the existing detector, the Beam-Beam Counter (BBC), with higher granularity and acceptance. The design of the EPD consists of two scintillator discs at z = +/- 3.75m from the center of STAR, covering 2.2 < η < 5.1. One quarter of a single disc was installed in STAR for the 2017 run for commissioning. In this talk we will discuss the detector performance during this commissioning run in both proton-proton collisions at √{ s = 510 } GeV and Au-Au collisions at √{sNN = 54.4 } GeV. NSF Grant 1614474.

Development of 10B-Based 3He Replacement Neutron Detectors

NASA Astrophysics Data System (ADS)

King, Michael J.; Gozani, Tsahi; Hilliard, Donald B.

2011-12-01

Radiation portal monitors (RPM) are currently deployed at United States border crossings to passively inspect vehicles and persons for any emission of neutrons and/or gamma rays, which may indicate the presence of unshielded nuclear materials. The RPM module contains an organic scintillator with 3He proportional counters to detect gamma rays and thermalized neutrons, respectively. The supply of 3He is rapidly dwindling, requiring alternative detectors to provide the same function and performance. Our alternative approach is one consisting of a thinly-coated 10B flat-panel ionization chamber neutron detector that can be deployed as a direct drop-in replacement for current RPM 3He detectors. The uniqueness of our approach in providing a large-area detector is in the simplicity of construction, scalability of the unit cell detector, ease of adaptability to a variety of applications and low cost. Currently, Rapiscan Laboratories and Helicon Thin Film Systems have designed and developed an operational 100 cm2 multi-layer prototype 10BB-based ionization chamber.

The influence of methionine-5-enkephalin on calcium uptake by the bovine aortic media.

PubMed

Kokkas, B; Kotoula, M; Kouyoumtzis, A; Kouvelas, D; Papadopoulos, K; Paradelis, A G

1990-04-01

The influence of methionine-5-enkephalin (M-5-E), an endogenous opioid receptor agonist, on calcium uptake by bovine aortic media was investigated in vitro. 45Ca was used and radioactivity was counted in a beta scintillation counter. M-5-E increases Ca2+ uptake by the preparation. This action is inhibited by naloxone and that is proof that an opioid receptor is stimulated. A comparative study showed that phenylephrine, an alpha-adrenoceptor agonist, exhibits the same action as M-5-E, whereas morphine's action is negligible. Phenylephrine contracts the deendotheliazed ring of the bovine aorta, whereas M-5-E fails to do so. It is concluded that an opioid receptor was identified at the bovine aortic smooth muscle. This receptor is stimulated by M-5-E resulting in an increase of the extracellular Ca2+ entrance. Although no relationship was observed between the receptor and the contraction mechanism, a possible role of M-5-E in the maintenance of the vascular tone cannot be excluded.

Development of a Simple Positron Age-Momentum Setup

NASA Astrophysics Data System (ADS)

Sheffield, Thomas; Quarles, C. A.

2009-04-01

A positron age-momentum setup that uses NIM Bin electronic modules and a conventional multichannel analyzer (MCA) is described. The essential idea is to accumulate a Doppler broadened spectrum (sensitive to the annihilation electron momentum) using a high purity Germanium detector in coincidence with a BaF2 scintillation counter, which also serves as the stop signal in a conventional positron lifetime setup. The MCA that collects the Doppler spectrum is gated by a selected region of the lifetime spectrum. Thus we can obtain Doppler broadening spectra as a function of positron lifetime: an age-momentum spectrum. The apparatus has been used so far to investigate a ZnO sample where the size of different vacancy trapping sites may affect the positron lifetime and the Doppler broadening spectrum. We are also looking at polymer and rubber carbon-black composite samples where differences in the Doppler spectrum may arise from positron trapping or positronium formation in the samples. Correction for background and contribution from the positron source itself to the Doppler spectrum will be discussed.

Use of relativistic rise in ionization chambers for measurement of high energy heavy nuclei

NASA Technical Reports Server (NTRS)

Barthelmy, S. D.; Israel, M. H.; Klarmann, J.; Vogel, J. S.

1983-01-01

A balloon-borne instrument has been constructed to measure the energy spectra of cosmic-ray heavy nuclei in the range of about 0.3 to about 100 GeV/amu. It makes use of the relativistic rise portion of the Bethe-Bloch curve in ionization chambers for energy determination in the 10- to 100-GeV/amu interval. The instrument consists of six layers of dual-gap ionization chambers for energy determination above 10 GeV/amu. Charge is determined with a NE114 scintillator and a Pilot 425 plastic Cerenkov counter. A CO2 gas Cerenkov detector (1 atm; threshold of 30 GeV/amu) calibrates the ion chambers in the relativistic rise region. The main emphasis of the instrument is the determination of the change of the ratio of Iron (26) to the Iron secondaries (21-25) in the energy range of 10 to 100 GeV/amu. Preliminary data from a balloon flight in the fall of 1982 from Palestine, TX is presented.

Interaction of Superconducting YBa2Cu(sub 3-x)Zn(sub x)O(sub 7-y) with MeV Radiation

NASA Technical Reports Server (NTRS)

Lewis, R. A.; Robertson, G. A.

2005-01-01

When the high Tc superconductor Y-Ba-Cu-O is cooled with liquid nitrogen, the conduction holes form a macroscopic collective or entangled state. While collective effects have been observed with radiation energies up to 5 eV, no high-sensitivity experiments have previously been carried out to search for comparable effects with MeV radiation. Here an experiment using a pair of scintillation counters arranged to search for changes in the natural background of high energy radiation adjacent to a warm and cold Y-Ba-Cu-O superconductor is described. The experiment showed a shift toward higher pulse heights when the SC was cooled, with a 4 standard deviation excess of 9.12+/-2.28 events/ksec over the range of 0 to 18 MeV. The net difference spectrum shows a 5.5 standard deviation excess signal for the range of 3 to 6 MeV.

Measurement of the inelastic proton-proton cross-section at √s=7 TeV with the ATLAS detector.

PubMed

2011-09-06

The dependence of the rate of proton-proton interactions on the centre-of-mass collision energy, √s, is of fundamental importance for both hadron collider physics and particle astrophysics. The dependence cannot yet be calculated from first principles; therefore, experimental measurements are needed. Here we present the first measurement of the inelastic proton-proton interaction cross-section at a centre-of-mass energy, √s, of 7 TeV using the ATLAS detector at the Large Hadron Collider. Events are selected by requiring hits on scintillation counters mounted in the forward region of the detector. An inelastic cross-section of 60.3 ± 2.1 mb is measured for ξ > 5×10⁻⁶, where ξ is calculated from the invariant mass, M(X), of hadrons selected using the largest rapidity gap in the event. For diffractive events, this corresponds to requiring at least one of the dissociation masses to be larger than 15.7 GeV.

Characterization of Silicon Photomultiplier Detectors using Cosmic Radiation

NASA Astrophysics Data System (ADS)

Zavala, Favian; Castro, Juan; Niduaza, Rexavalmar; Wedel, Zachary; Fan, Sewan; Ritt, Stefan; Fatuzzo, Laura

2014-03-01

The silicon photomultiplier light detector has gained a lot of attention lately in fields such as particle physics, astrophysics, and medical physics. Its popularity stems from its lower cost, compact size, insensitivity to magnetic fields, and its excellent ability to distinguish a quantized number of photons. They are normally operated at room temperature and biased above their breakdown voltages. As such, they may also exhibit properties that may hinder their optimal operation which include a thermally induced high dark count rate, after pulse effects, and cross talk from photons in nearby pixels. At this poster session, we describe our data analysis and our endeavor to characterize the multipixel photon counter (MPPC) detectors from Hamamatsu under different bias voltages and temperature conditions. Particularly, we describe our setup which uses cosmic rays to induce scintillation light delivered to the detector by wavelength shifting optical fibers and the use of a fast 1 GHz waveform sampler, the domino ring sampler (DRS4) digitizer board. Department of Education grant number P031S90007.

Probing Cherenkov and Scintillation Light Separation for Next-Generation Neutrino Detectors

NASA Astrophysics Data System (ADS)

Caravaca, J.; Descamps, F. B.; Land, B. J.; Orebi Gann, G. D.; Wallig, J.; Yeh, M.

2017-09-01

The ability to separate Cherenkov and scintillation signals in liquid scintillator detectors would enable outstanding background rejection for next-generation neutrino experiments. Reconstruction of directional information, ring imaging, and sub-Cherenkov threshold detection all have the potential to substantially improve particle and event identification. The Cherenkov-Scintillation Separation (CHESS) experiment uses an array of small, fast photomultipliers (PMTs) and state-of-the-art electronics to demonstrate the reconstruction of a Cherenkov ring in a scintillation medium based on photon hit times and detected charge. This setup has been used to characterize the ability to detect Cherenkov light in a range of target media. We show results with pure organic scintillator (LAB) and the prospects with scintillators with a secondary fluor (LAB/PPO). There are future plans to deploy the newly developed water-based liquid scintillator, a medium with a higher Cherenkov/Scintillation light yield ratio than conventional pure liquid scintillators, enhancing the visibility of the less abundant Cherenkov light in the presence of scintillation light. These results can inform the development of future large-scale detectors, such as the proposed Theia experiment, or other large detectors at underground laboratories such as the far-site of the new Long Baseline Neutrino Facility at the Sanford Underground Research Facility. CHESS detector calibrations and commissioning will be discussed, and the latest results will be presented.

Comparison of multifrequency equatorial scintillation - American and Pacific sectors

NASA Astrophysics Data System (ADS)

Livingston, R. C.

1980-08-01

In this paper we examine the severity of radio wave amplitude scintillation measured at two stations near the equator but far separated in longitude: Kwajelein, Marshall Islands (167 E), and Ancon, Peru (-77 E). The data used are long-term observations of the Defense Nuclear Agency (DNA) Wideband satellite signal intensity at VHF, UHF, and L band frequencies. The seasonal behavior of the scintillation at the two stations is similar; each shows a broad 8- to 9-month disturbed season centered about local summer. There is short-term variability in the scintillation occurrence statistics but no clear equinoctial maxima. Little difference is observed in the occurrence or severity of L band scintillation at the two stations, although a systematic difference in the frequency dependence of the scintillation produces significantly stronger VHF and UHF scintillation at Ancon. The VHF and UHF latitudinal distributions of scintillation are asymmetric about the geomagnetic equator at both stations.

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.

Characterizing Daytime GHZ Scintillation at Equatorial Regions Using Gnss Radio Occultation Measurements

NASA Astrophysics Data System (ADS)

Seif, A.; Zhang, K.; Tsunoda, R. T.; Abdullah, M.; Carter, B. A.; Norman, R.; Wu, S.

2015-12-01

Ionospheric scintillation of radio waves can behave differently at different locations with a strong diurnal dependence; particularly in the equatorial regions. Ionospheric scintillations at gigahertz (GHz) frequencies have been observed during both daytime and nighttime. It is believed that daytime scintillation is associated with blanketing sporadic E (Esb), whereas nighttime scintillation is attributed to F layer irregularities. Scintillation events associated with Esbduring daytime are of our primary interest. Recent studies show that in the ionosphere, electron density profiles from Global Navigation Satellite System (GNSS) Radio Occultation (RO) provide valuable information to help better understand the physics of the ionosphere. In particular, GNSS RO observations of GHz scintillation in the proximity of the E-layer have been interpreted as being caused by sporadic E. In this paper the characteristics of daytime scintillations at 1.5 GHz recorded simultaneously from two stations (i) Universiti Kebangsaan Malaysia (UKM) (2.55°N, 101.461°E; dip latitude 5.78°S), and (ii) Langkawi (6.19°N, 99.51°E; dip latitude 1.90°S) during November and December 2010 are analyzed. The characteristics of daytime GHz scintillation and its relationship with E region irregularities at equatorial regions are investigated. Ground-based scintillation and Total Electron Content (TEC) data recorded by the GSV4004 receivers were utilized in combination with the amplitude scintillation measurements in terms of GPS C/A code SNR fluctuations during a ground-based GPS and space-borne GNSS RO experiment at the two equatorial stations. Scintillation activity was found to be more prominent at UKM. Moreover, strong scintillation with the S4 index exceeding 0.6 has only been observed at UKM, while at Langkawi the scintillation intensity (S4 index) did not exceed 0.3. Signal-to-noise measurements obtained from GNSS RO indicate that daytime scintillations are very likely caused by Esb. Our further research will be concentrated on an in-depth investigation of day-time irregularities in equatorial regions using both ground and space-borne GNSS technologies.

Equatorial scintillation and systems support

NASA Astrophysics Data System (ADS)

Groves, K. M.; Basu, S.; Weber, E. J.; Smitham, M.; Kuenzler, H.; Valladares, C. E.; Sheehan, R.; MacKenzie, E.; Secan, J. A.; Ning, P.; McNeill, W. J.; Moonan, D. W.; Kendra, M. J.

1997-09-01

The need to nowcast and forecast scintillation for the support of operational systems has been recently identified by the interagency National Space Weather Program. This issue is addressed in the present paper in the context of nighttime irregularities in the equatorial ionosphere that cause intense amplitude and phase scintillations of satellite signals in the VHF/UHF range of frequencies and impact satellite communication, Global Positioning System navigation, and radar systems. Multistation and multifrequency satellite scintillation observations have been used to show that even though equatorial scintillations vary in accordance with the solar cycle, the extreme day-to-day variability of unknown origin modulates the scintillation occurrence during all phases of the solar cycle. It is shown that although equatorial scintillation events often show correlation with magnetic activity, the major component of scintillation is observed during magnetically quiet periods. In view of the day-to-day variability of the occurrence and intensity of scintillating regions, their latitude extent, and their zonal motion, a regional specification and short-term forecast system based on real-time measurements has been developed. This system, named the Scintillation Network Decision Aid, consists of two latitudinally dispersed stations, each of which uses spaced antenna scintillation receiving systems to monitor 250-MHz transmissions from two longitudinally separated geostationary satellites. The scintillation index and zonal irregularity drift are processed on-line and are retrieved by a remote operator on the Internet. At the operator terminal the data are combined with an empirical plasma bubble model to generate three-dimensional maps of irregularity structures and two-dimensional outage maps for the region.

Positron source position sensing detector and electronics

DOEpatents

Burnham, Charles A.; Bradshaw, Jr., John F.; Kaufman, David E.; Chesler, David A.; Brownell, Gordon L.

1985-01-01

A positron source, position sensing device, particularly with medical applications, in which positron induced gamma radiation is detected using a ring of stacked, individual scintillation crystals, a plurality of photodetectors, separated from the scintillation crystals by a light guide, and high resolution position interpolation electronics. Preferably the scintillation crystals are several times more numerous than the photodetectors with each crystal being responsible for a single scintillation event from a received gamma ray. The light guide will disperse the light emitted from gamma ray absorption over several photodetectors. Processing electronics for the output of the photodetectors resolves the location of the scintillation event to a fraction of the dimension of each photodetector. Because each positron absorption results in two 180.degree. oppositely traveling gamma rays, the detection of scintillation in pairs permits location of the positron source in a manner useful for diagnostic purposes. The processing electronics simultaneously responds to the outputs of the photodetectors to locate the scintillations to the source crystal. While it is preferable that the scintillation crystal include a plurality of stacked crystal elements, the resolving power of the processing electronics is also applicable to continuous crystal scintillators.

Novel scintillating material 2-(4-styrylphenyl)benzoxazole for the fully digital and MRI compatible J-PET tomograph based on plastic scintillators

PubMed Central

Dulski, Kamil; Niedźwiecki, Szymon; Alfs, Dominika; Białas, Piotr; Curceanu, Catalina; Czerwiński, Eryk; Danel, Andrzej; Gajos, Aleksander; Głowacz, Bartosz; Gorgol, Marek; Hiesmayr, Beatrix; Jasińska, Bożena; Kacprzak, Krzysztof; Kamińska, Daria; Kapłon, Łukasz; Kochanowski, Andrzej; Korcyl, Grzegorz; Kowalski, Paweł; Kozik, Tomasz; Krzemień, Wojciech; Kubicz, Ewelina; Kucharek, Mateusz; Mohammed, Muhsin; Pawlik-Niedźwiecka, Monika; Pałka, Marek; Raczyński, Lech; Rudy, Zbigniew; Rundel, Oleksandr; Sharma, Neha G.; Silarski, Michał; Uchacz, Tomasz; Wiślicki, Wojciech; Zgardzińska, Bożena; Zieliński, Marcin; Moskal, Paweł

2017-01-01

A novel plastic scintillator is developed for the application in the digital positron emission tomography (PET). The novelty of the concept lies in application of the 2-(4-styrylphenyl)benzoxazole as a wavelength shifter. The substance has not been used as scintillator dopant before. A dopant shifts the scintillation spectrum towards longer wavelengths making it more suitable for applications in scintillators of long strips geometry and light detection with digital silicon photomultipliers. These features open perspectives for the construction of the cost-effective and MRI-compatible PET scanner with the large field of view. In this article we present the synthesis method and characterize performance of the elaborated scintillator by determining its light emission spectrum, light emission efficiency, rising and decay time of the scintillation pulses and resulting timing resolution when applied in the positron emission tomography. The optimal concentration of the novel wavelength shifter was established by maximizing the light output and it was found to be 0.05 ‰ for cuboidal scintillator with dimensions of 14 mm x 14 mm x 20 mm. PMID:29176834

Novel scintillating material 2-(4-styrylphenyl)benzoxazole for the fully digital and MRI compatible J-PET tomograph based on plastic scintillators.

PubMed

Wieczorek, Anna; Dulski, Kamil; Niedźwiecki, Szymon; Alfs, Dominika; Białas, Piotr; Curceanu, Catalina; Czerwiński, Eryk; Danel, Andrzej; Gajos, Aleksander; Głowacz, Bartosz; Gorgol, Marek; Hiesmayr, Beatrix; Jasińska, Bożena; Kacprzak, Krzysztof; Kamińska, Daria; Kapłon, Łukasz; Kochanowski, Andrzej; Korcyl, Grzegorz; Kowalski, Paweł; Kozik, Tomasz; Krzemień, Wojciech; Kubicz, Ewelina; Kucharek, Mateusz; Mohammed, Muhsin; Pawlik-Niedźwiecka, Monika; Pałka, Marek; Raczyński, Lech; Rudy, Zbigniew; Rundel, Oleksandr; Sharma, Neha G; Silarski, Michał; Uchacz, Tomasz; Wiślicki, Wojciech; Zgardzińska, Bożena; Zieliński, Marcin; Moskal, Paweł

2017-01-01

A novel plastic scintillator is developed for the application in the digital positron emission tomography (PET). The novelty of the concept lies in application of the 2-(4-styrylphenyl)benzoxazole as a wavelength shifter. The substance has not been used as scintillator dopant before. A dopant shifts the scintillation spectrum towards longer wavelengths making it more suitable for applications in scintillators of long strips geometry and light detection with digital silicon photomultipliers. These features open perspectives for the construction of the cost-effective and MRI-compatible PET scanner with the large field of view. In this article we present the synthesis method and characterize performance of the elaborated scintillator by determining its light emission spectrum, light emission efficiency, rising and decay time of the scintillation pulses and resulting timing resolution when applied in the positron emission tomography. The optimal concentration of the novel wavelength shifter was established by maximizing the light output and it was found to be 0.05 ‰ for cuboidal scintillator with dimensions of 14 mm x 14 mm x 20 mm.

A first comparison of the responses of a 4He-based fast-neutron detector and a NE-213 liquid-scintillator reference detector

NASA Astrophysics Data System (ADS)

Jebali, R.; Scherzinger, J.; Annand, J. R. M.; Chandra, R.; Davatz, G.; Fissum, K. G.; Friederich, H.; Gendotti, U.; Hall-Wilton, R.; Håkansson, E.; Kanaki, K.; Lundin, M.; Murer, D.; Nilsson, B.; Rosborg, A.; Svensson, H.

2015-09-01

A first comparison has been made between the pulse-shape discrimination characteristics of a novel 4He-based pressurized scintillation detector and a NE-213 liquid-scintillator reference detector using an Am/Be mixed-field neutron and gamma-ray source and a high-resolution scintillation-pulse digitizer. In particular, the capabilities of the two fast neutron detectors to discriminate between neutrons and gamma-rays were investigated. The NE-213 liquid-scintillator reference cell produced a wide range of scintillation-light yields in response to the gamma-ray field of the source. In stark contrast, due to the size and pressure of the 4He gas volume, the 4He-based detector registered a maximum scintillation-light yield of 750keVee to the same gamma-ray field. Pulse-shape discrimination for particles with scintillation-light yields of more than 750keVee was excellent in the case of the 4He-based detector. Above 750keVee its signal was unambiguously neutron, enabling particle identification based entirely upon the amount of scintillation light produced.

Cherenkov and scintillation light separation on the TheiaR &D experiment

NASA Astrophysics Data System (ADS)

Caravaca, Javier; Land, Benjamin

2016-03-01

Identifying by separate the scintillation and Cherenkov light produced in a scintillation medium enables outstanding capabilities for future particle detectors, being the most relevant: allowing particle directionality information in a low energy threshold detector and improved particle identification. The TheiaR &D experiment uses an array of small and fast photomultipliers (PMTs) and state-of-the-art electronics to demonstrate the reconstruction of a Cherenkov ring in a scintillation medium, based on the number of produced photoelectrons and the timing information. A charged particle ionizing a scintillation medium produces a prompt Cherenkov cone and late isotropic scintillation light, typically delayed by <1ns. The fast response of our PMTs and DAQ provides a precision well below the ns level, making possible the time separation. Furthermore, the usage of the new developed water-based liquid scintillators (WBLS) provides a medium with a tunable Cherenkov/Scintillation light yield ratio, enhancing the visibility of the dimer Cherenkov light in presence of the scintillation light. Description of the experiment, details of the analysis and preliminary results of the first months of running will be discussed.

Scintillation imaging of tritium radioactivity distribution during tritiated thymidine uptake by PC12 cells using a melt-on scintillator.

PubMed

Irikura, Namiko; Miyoshi, Hirokazu; Shinohara, Yasuo

2017-02-01

A scintillation image of tritium fixed in a melt-on scintillator was obtained using a charged-coupled device (CCD) imager, and a linear relationship was observed between the intensity of the scintillation image and the radioactivity of tritium. In a [ 3 H]thymidine uptake experiment, a linear correlation between the intensity of the CCD image and the dilution ratio of cells was confirmed. Scintillation imaging has the potential for use in direct observation of tritium radioactivity distribution. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Apertured averaged scintillation of fully and partially coherent Gaussian, annular Gaussian, flat toped and dark hollow beams

NASA Astrophysics Data System (ADS)

Eyyuboğlu, Halil T.

2015-03-01

Apertured averaged scintillation requires the evaluation of rather complicated irradiance covariance function. Here we develop a much simpler numerical method based on our earlier introduced semi-analytic approach. Using this method, we calculate aperture averaged scintillation of fully and partially coherent Gaussian, annular Gaussian flat topped and dark hollow beams. For comparison, the principles of equal source beam power and normalizing the aperture averaged scintillation with respect to received power are applied. Our results indicate that for fully coherent beams, upon adjusting the aperture sizes to capture 10 and 20% of the equal source power, Gaussian beam needs the largest aperture opening, yielding the lowest aperture average scintillation, whilst the opposite occurs for annular Gaussian and dark hollow beams. When assessed on the basis of received power normalized aperture averaged scintillation, fixed propagation distance and aperture size, annular Gaussian and dark hollow beams seem to have the lowest scintillation. Just like the case of point-like scintillation, partially coherent beams will offer less aperture averaged scintillation in comparison to fully coherent beams. But this performance improvement relies on larger aperture openings. Upon normalizing the aperture averaged scintillation with respect to received power, fully coherent beams become more advantageous than partially coherent ones.

Ionospheric scintillation observations over Kenyan region - Preliminary results

NASA Astrophysics Data System (ADS)

Olwendo, O. J.; Xiao, Yu; Ming, Ou

2016-11-01

Ionospheric scintillation refers to the rapid fluctuations in the amplitude and phase of a satellite signal as it passes through small-scale plasma density irregularities in the ionosphere. By analyzing ionospheric scintillation observation datasets from satellite signals such as GPS signals we can study the morphology of ionospheric bubbles. At low latitudes, the diurnal behavior of scintillation is driven by the formation of large-scale equatorial density depletions which form one to two hours after sunset via the Rayleigh-Taylor instability mechanism near the magnetic equator. In this work we present ionospheric scintillation activity over Kenya using data derived from a newly installed scintillation monitor developed by CRIRP at Pwani University (39.78°E, 3.24°S) during the period August to December, 2014. The results reveal the scintillation activity mainly occurs from post-sunset to post-midnight hours, and ceases around 04:00 LT. We also found that the ionospheric scintillation tends to appear at the southwest and northwest of the station. These locations coincide with the southern part of the Equatorial Ionization Anomaly crest over Kenya region. The occurrence of post-midnight L-band scintillation events which are not linked to pre-midnight scintillation observations raises fundamental question on the mechanism and source of electric fields driving the plasma depletion under conditions of very low background electron density.

A multi-instrument case study of high-latitude ionospheric GNSS scintillation due to drifting plasma irregularities

NASA Astrophysics Data System (ADS)

van der Meeren, C.; Oksavik, K.; Moen, J. I.; Romano, V.

2013-12-01

For this study, GPS receiver scintillation and Total Electron Content (TEC) data from high-latitude locations on Svalbard have been combined with several other data sets, including the EISCAT Svalbard Radar (ESR) and allsky cameras, to perform a multi-instrument case study of high-latitude GPS ionospheric scintillations in relation to drifting plasma irregularities at night over Svalbard on 31 October 2011. Scintillations are rapid amplitude and phase fluctuations of electromagnetic signals. GNSS-based systems may be disturbed by ionospheric plasma irregularities and structures such as plasma patches (areas of enhanced electron density in the polar cap) and plasma gradients. When the GNSS radio signals propagate through such areas, in particular gradients, the signals experience scintillations that at best increases positioning errors and at worst may break the receiver's signal lock, potentially resulting in the GNSS receiver losing track of its position. Due to the importance of many GNSS applications, it is desirable to study the scintillation environment to understand the limitations of the GNSS systems. We find scintillation mainly localised to plasma gradients, with predominantly phase scintillation at the leading edge of patches and both phase and amplitude scintillation at the trailing edge. A single edge may also contain different scintillation types at different locations.

Upconverting nanoparticles for optimizing scintillator based detection systems

DOEpatents

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

2013-09-17

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

Radiation damage effects on the optical properties of plastic scintillators

NASA Astrophysics Data System (ADS)

Jivan, H.; Mdhluli, J. E.; Sideras-Haddad, E.; Mellado, B.; Erasmus, R.; Madhuku, M.

2017-10-01

We report on the radiation damage to the optical properties of plastic scintillators following irradiation using a 6 MeV proton beam produced by the 6 MV tandem accelerator of iThemba LABS, Gauteng. A comparative is drawn between polyvinyl toluene based commercial scintillators EJ200, EJ208, EJ260 and BC408 as well as polystyrene based scintillator UPS923A and scintillators manufactured for the Tile Calorimeter. Results on the proton induced damage indicate a reduction in the light output and transmission capability of the plastics. Scintillators containing a larger Stokes shift, i.e. EJ260 and EJ208 exhibit the most radiation hardness. The EJ208 is recommended as a candidate to be considered for the replacement of Gap scintillators in the Tile Calorimeter for the 2018 upgrade.

Comparison of neutron spectra measured with three sizes of organic liquid scintillators using differentiation analysis

NASA Technical Reports Server (NTRS)

Shook, D. F.; Pierce, C. R.

1972-01-01

Proton recoil distributions were obtained by using organic liquid scintillators of different size. The measured distributions are converted to neutron spectra by differentiation analysis for comparison to the unfolded spectra of the largest scintillator. The approximations involved in the differentiation analysis are indicated to have small effects on the precision of neutron spectra measured with the smaller scintillators but introduce significant error for the largest scintillator. In the case of the smallest cylindrical scintillator, nominally 1.2 by 1.3 cm, the efficiency is shown to be insensitive to multiple scattering and to the angular distribution to the incident flux. These characteristics of the smaller scintillator make possible its use to measure scalar flux spectra within media high efficiency is not required.

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera.

PubMed

Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G; Nagarkar, Vivek V

2011-06-01

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional "straight-cut" (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

PubMed Central

Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G.; Nagarkar, Vivek V.

2011-01-01

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional “straight-cut” (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors. PMID:21731108

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

NASA Astrophysics Data System (ADS)

Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G.; Nagarkar, Vivek V.

2011-06-01

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99 m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional “straight-cut” (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

Spacecraft Radio Scintillation and Solar System Exploration

NASA Technical Reports Server (NTRS)

Woo, Richard

1993-01-01

When a wave propagates through a turbulent medium, scattering by the random refractive index inhomogeneities can lead to a wide variety of phenomena that have been the subject of extensive study. The observed scattering effects include amplitude or intensity scintillation, phase scintillation, angular broadening, and spectral broadening, among others. In this paper, I will refer to these scattering effects collectively as scintillation. Although the most familiar example is probably the twinkling of stars (light wave intensity scintillation by turbulence in the Earth's atmosphere), scintillation has been encountered and investigated in such diverse fields as ionospheric physics, oceanography, radio astronomy, and radio and optical communications. Ever since planetary spacecraft began exploring the solar system, scintillation has appeared during the propagation of spacecraft radio signals through planetary atmospheres, planetary ionospheres, and the solar wind. Early studies of these phenomena were motivated by the potential adverse effects on communications and navigation, and on experiments that use the radio link to conduct scientific investigations. Examples of the latter are radio occultation measurements (described below) of planetary atmospheres to deduce temperature profiles, and the search for gravitational waves. However,these concerns soon gave way to the emergence of spacecraft radio scintillation as a new scientific tool for exploring small-scale dynamics in planetary atmospheres and structure in the solar wind, complementing in situ and other remote sensing spacecraft measurements, as well as scintillation measurements using natural (celestial) radio sources. The purpose of this paper is to briefly describe and review the solar system spacecraft radio scintillation observations, to summarize the salient features of wave propagation analyses employed in interpreting them, to underscore the unique remote sensing capabilities and scientific relevance of the scintillation measurements, and to highlight some of the scientific results obtained to date. Special emphasis is placed on comparing the remote sensing features of planetary and terrestrial scintillation measurements, and on contrasting spacecraft and natural radio source scintillation measurements. I will first discuss planetary atmospheres and ionospheres, and then the solar wind.

The Ionospheric Scintillation Effects on the BeiDou Signal Receiver

PubMed Central

He, Zhijun; Zhao, Hongbo; Feng, Wenquan

2016-01-01

Irregularities in the Earth’s ionosphere can make the amplitude and phase of radio signals fluctuate rapidly, which is known as ionospheric scintillation. Severe ionospheric scintillation could affect the performance of the Global Navigation Satellite System (GNSS). Currently, the Multiple Phase Screen (MPS) technique is widely used in solving problems caused by weak and strong scintillations. Considering that Southern China is mainly located in the area where moderate and intense scintillation occur frequently, this paper built a model based on the MPS technique and discussed the scintillation impacts on China’s BeiDou navigation system. By using the BeiDou B1I signal, this paper analyzed the scintillation effects on the receiver, which includes the acquisition and tracking process. For acquisition process, this paper focused on the correlation peak and acquisition probability. For the tracking process, this paper focused on the carrier tracking loop and the code tracking loop. Simulation results show that under high scintillation intensity, the phase fluctuation could be −1.13 ± 0.087 rad to 1.40 ± 0.087 rad and the relative amplitude fluctuation could be −10 dB to 8 dB. As the scintillation intensity increased, the average correlation peak would decrease more than 8%, which could thus degrade acquisition performance. On the other hand, when the signal-to-noise ratio (SNR) is comparatively lower, the influence of strong scintillation on the phase locked loop (PLL) is much higher than that of weak scintillation. As the scintillation becomes more intense, PLL variance could consequently results in an error of more than 2.02 cm in carrier-phase based ranging. In addition, the delay locked loop (DLL) simulation results indicated that the pseudo-range error caused by strong scintillation could be more than 4 m and the consequent impact on positioning accuracy could be more than 6 m. PMID:27834867

Development of a large area microstructure photomultiplier assembly (LAMPA)

NASA Astrophysics Data System (ADS)

Clifford, E. T. H.; Dick, M.; Facina, M.; Wakeford, D.; Andrews, H. R.; Ing, H.; Best, D.; Baginski, M. J.

2017-05-01

Large area (> m2) position-sensitive readout of scintillators is important for passive/active gamma and neutron imaging for counter-terrorism applications. The goal of the LAMPA project is to provide a novel, affordable, large-area photodetector (8" x 8") by replacing the conventional dynodes of photomultiplier tubes (PMTs) with electron multiplier microstructure boards (MSBs) that can be produced using industrial manufacturing techniques. The square, planar format of the LAMPA assemblies enables tiling of multiple units to support large area applications. The LAMPA performance objectives include comparable gain, noise, timing, and energy resolution relative to conventional PMTs, as well as spatial resolution in the few mm range. The current LAMPA prototype is a stack of 8" x 8" MSBs made commercially by chemical etching of a molybdenum substrate and coated with hydrogen-terminated boron-doped diamond for high secondary emission yield (SEY). The layers of MSBs are electrically isolated using ceramic standoffs. Field-shaping grids are located between adjacent boards to achieve good transmission of electrons from one board to the next. The spacing between layers and the design of the microstructure pattern and grids were guided by simulations performed using an electro-optics code. A position sensitive anode board at the back of the stack of MSBs provides 2-D readout. This presentation discusses the trade studies performed in the design of the MSBs, the measurements of SEY from various electro-emissive materials, the electro-optics simulations conducted, the design of the 2-D readout, and the mechanical aspects of the LAMPA design, in order to achieve a gain of > 104 in an 8-stage stack of MSBs, suitable for use with various scintillators when coupled to an appropriate photocathode.

Intrinsic spatial resolution evaluation of the X'tal cube PET detector based on a 3D crystal block segmented by laser processing.

PubMed

Yoshida, Eiji; Tashima, Hideaki; Inadama, Naoko; Nishikido, Fumihiko; Moriya, Takahiro; Omura, Tomohide; Watanabe, Mitsuo; Murayama, Hideo; Yamaya, Taiga

2013-01-01

The X'tal cube is a depth-of-interaction (DOI)-PET detector which is aimed at obtaining isotropic resolution by effective readout of scintillation photons from the six sides of a crystal block. The X'tal cube is composed of the 3D crystal block with isotropic resolution and arrays of multi-pixel photon counters (MPPCs). In this study, to fabricate the 3D crystal block efficiently and precisely, we applied a sub-surface laser engraving (SSLE) technique to a monolithic crystal block instead of gluing segmented small crystals. The SSLE technique provided micro-crack walls which carve a groove into a monolithic scintillator block. Using the fabricated X'tal cube, we evaluated its intrinsic spatial resolution to show a proof of concept of isotropic resolution. The 3D grids of 2 mm pitch were fabricated into an 18 × 18 × 18 mm(3) monolithic lutetium yttrium orthosilicate (LYSO) crystal by the SSLE technique. 4 × 4 MPPCs were optically coupled to each surface of the crystal block. The X'tal cube was uniformly irradiated by (22)Na gamma rays, and all of the 3D grids on the 3D position histogram were separated clearly by an Anger-type calculation from the 96-channel MPPC signals. Response functions of the X'tal cube were measured by scanning with a (22)Na point source. The gamma-ray beam with a 1.0 mm slit was scanned in 0.25 mm steps by positioning of the X'tal cube at vertical and 45° incident angles. The average FWHM resolution at both incident angles was 2.1 mm. Therefore, we confirmed the isotropic spatial resolution performance of the X'tal cube.

A SiPM-based isotropic-3D PET detector X'tal cube with a three-dimensional array of 1 mm(3) crystals.

PubMed

Yamaya, Taiga; Mitsuhashi, Takayuki; Matsumoto, Takahiro; Inadama, Naoko; Nishikido, Fumihiko; Yoshida, Eiji; Murayama, Hideo; Kawai, Hideyuki; Suga, Mikio; Watanabe, Mitsuo

2011-11-07

We are developing a novel, general purpose isotropic-3D PET detector X'tal cube which has high spatial resolution in all three dimensions. The research challenge for this detector is implementing effective detection of scintillation photons by covering six faces of a segmented crystal block with silicon photomultipliers (SiPMs). In this paper, we developed the second prototype of the X'tal cube for a proof-of-concept. We aimed at realizing an ultimate detector with 1.0 mm(3) cubic crystals, in contrast to our previous development using 3.0 mm(3) cubic crystals. The crystal block was composed of a 16 × 16 × 16 array of lutetium gadolinium oxyorthosilicate (LGSO) crystals 0.993 × 0.993 × 0.993 mm(3) in size. The crystals were optically glued together without inserting any reflector inside and 96 multi-pixel photon counters (MPPCs, S10931-50P, i.e. six faces each with a 4 × 4 array of MPPCs), each having a sensitive area of 3.0 × 3.0 mm(2), were optically coupled to the surfaces of the crystal block. Almost all 4096 crystals were identified through Anger-type calculation due to the finely adjusted reflector sheets inserted between the crystal block and light guides. The reflector sheets, which formed a belt of 0.5 mm width, were placed to cover half of the crystals of the second rows from the edges in order to improve identification performance of the crystals near the edges. Energy resolution of 12.7% was obtained at 511 keV with almost uniform light output for all crystal segments thanks to the effective detection of the scintillation photons.

Iterative Focused Screening with Biological Fingerprints Identifies Selective Asc-1 Inhibitors Distinct from Traditional High Throughput Screening.

PubMed

Kutchukian, Peter S; Warren, Lee; Magliaro, Brian C; Amoss, Adam; Cassaday, Jason A; O'Donnell, Gregory; Squadroni, Brian; Zuck, Paul; Pascarella, Danette; Culberson, J Chris; Cooke, Andrew J; Hurzy, Danielle; Schlegel, Kelly-Ann Sondra; Thomson, Fiona; Johnson, Eric N; Uebele, Victor N; Hermes, Jeffrey D; Parmentier-Batteur, Sophie; Finley, Michael

2017-02-17

N-methyl-d-aspartate receptors (NMDARs) mediate glutamatergic signaling that is critical to cognitive processes in the central nervous system, and NMDAR hypofunction is thought to contribute to cognitive impairment observed in both schizophrenia and Alzheimer's disease. One approach to enhance the function of NMDAR is to increase the concentration of an NMDAR coagonist, such as glycine or d-serine, in the synaptic cleft. Inhibition of alanine-serine-cysteine transporter-1 (Asc-1), the primary transporter of d-serine, is attractive because the transporter is localized to neurons in brain regions critical to cognitive function, including the hippocampus and cortical layers III and IV, and is colocalized with d-serine and NMDARs. To identify novel Asc-1 inhibitors, two different screening approaches were performed with whole-cell amino acid uptake in heterologous cells stably expressing human Asc-1: (1) a high-throughput screen (HTS) of 3 M compounds measuring 35 S l-cysteine uptake into cells attached to scintillation proximity assay beads in a 1536 well format and (2) an iterative focused screen (IFS) of a 45 000 compound diversity set using a 3 H d-serine uptake assay with a liquid scintillation plate reader in a 384 well format. Critically important for both screening approaches was the implementation of counter screens to remove nonspecific inhibitors of radioactive amino acid uptake. Furthermore, a 15 000 compound expansion step incorporating both on- and off-target data into chemical and biological fingerprint-based models for selection of additional hits enabled the identification of novel Asc-1-selective chemical matter from the IFS that was not identified in the full-collection HTS.

GPU-based optical propagation simulator of a laser-processed crystal block for the X'tal cube PET detector.

PubMed

Ogata, Yuma; Ohnishi, Takashi; Moriya, Takahiro; Inadama, Naoko; Nishikido, Fumihiko; Yoshida, Eiji; Murayama, Hideo; Yamaya, Taiga; Haneishi, Hideaki

2014-01-01

The X'tal cube is a next-generation DOI detector for PET that we are developing to offer higher resolution and higher sensitivity than is available with present detectors. It is constructed from a cubic monolithic scintillation crystal and silicon photomultipliers which are coupled on various positions of the six surfaces of the cube. A laser-processing technique is applied to produce 3D optical boundaries composed of micro-cracks inside the monolithic scintillator crystal. The current configuration is based on an empirical trial of a laser-processed boundary. There is room to improve the spatial resolution by optimizing the setting of the laser-processed boundary. In fact, the laser-processing technique has high freedom in setting the parameters of the boundary such as size, pitch, and angle. Computer simulation can effectively optimize such parameters. In this study, to design optical characteristics properly for the laser-processed crystal, we developed a Monte Carlo simulator which can model arbitrary arrangements of laser-processed optical boundaries (LPBs). The optical characteristics of the LPBs were measured by use of a setup with a laser and a photo-diode, and then modeled in the simulator. The accuracy of the simulator was confirmed by comparison of position histograms obtained from the simulation and from experiments with a prototype detector composed of a cubic LYSO monolithic crystal with 6 × 6 × 6 segments and multi-pixel photon counters. Furthermore, the simulator was accelerated by parallel computing with general-purpose computing on a graphics processing unit. The calculation speed was about 400 times faster than that with a CPU.

N-(2-Ethylhexyl)carbazole: A New Fluorophore Highly Suitable as a Monomolecular Liquid Scintillator.

PubMed

Montbarbon, Eva; Sguerra, Fabien; Bertrand, Guillaume H V; Magnier, Élodie; Coulon, Romain; Pansu, Robert B; Hamel, Matthieu

2016-08-16

The synthesis, photophysical properties, and applications in scintillation counting of N-(2-ethylhexyl)carbazole (EHCz) are reported. This molecule displays all of the required characteristics for an efficient liquid scintillator (emission wavelength, scintillation yield), and can be used without any extra fluorophores. Thus, its scintillation properties are discussed, as well as its fast neutron/gamma discrimination. For the latter application, the material is compared with the traditional liquid scintillator BC-501 A, and other liquid fluorescent molecules classically used as scintillation solvents, such as xylene, pseudocumene (PC), linear alkylbenzenes (LAB), diisopropylnaphthalene (DIN), 1-methylnaphthalene (1-MeNapht), and 4-isopropylbiphenyl (iPrBiph). For the first time, an excimeric form of a molecule has been advantageously used in scintillation counting. A moderate discrimination between fast neutrons and gamma rays was observed in bulk EHCz, with an apparent neutron/gamma discrimination potential half of that of BC-501 A. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scintillation properties of dark hollow beams in a weak turbulent atmosphere

NASA Astrophysics Data System (ADS)

Chen, Y.; Cai, Y.; Eyyuboğlu, H. T.; Baykal, Y.

2008-01-01

The on-axis scintillation index for a circular dark hollow beam (DHB) propagating in a weak turbulent atmosphere is formulated, and the scintillation properties of a DHB are investigated in detail. The scintillation index for a DHB reduces to the scintillation index for a Gaussian beam, an annular beam and a flat-topped beam under certain conditions. It is found that the scintillation index of a DHB is closely related to the beam parameters and can be lower than that of a Gaussian beam, an annular beam and a flat-topped beam in a weak turbulent atmosphere at smaller waist sizes and longer propagation lengths.

Simultaneous beta and gamma spectroscopy

DOEpatents

Farsoni, Abdollah T.; Hamby, David M.

2010-03-23

A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

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.

Scintillation decay time and pulse shape discrimination in oxygenated and deoxygenated solutions of linear alkylbenzene for the SNO+ experiment

NASA Astrophysics Data System (ADS)

O'Keeffe, H. M.; O'Sullivan, E.; Chen, M. C.

2011-06-01

The SNO+ liquid scintillator experiment is under construction in the SNOLAB facility in Canada. The success of this experiment relies upon accurate characterization of the liquid scintillator, linear alkylbenzene (LAB). In this paper, scintillation decay times for alpha and electron excitations in LAB with 2 g/L PPO are presented for both oxygenated and deoxygenated solutions. While deoxygenation is expected to improve pulse shape discrimination in liquid scintillators, it is not commonly demonstrated in the literature. This paper shows that for linear alkylbenzene, deoxygenation improves discrimination between electron and alpha excitations in the scintillator.

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

Co-doping effects on luminescence and scintillation properties of Ce doped (Lu,Gd)3(Ga,Al)5O12 scintillator

NASA Astrophysics Data System (ADS)

Yamaguchi, Hiroaki; Kamada, Kei; Kurosawa, Shunsuke; Pejchal, Jan; Shoji, Yasuhiro; Yokota, Yuui; Ohashi, Yuji; Yoshikawa, Akira

2016-11-01

Mg co-doping effects on scintillation properties of Ce:Lu1Gd2(Ga,Al)5O12 (LGGAG) were investigated. Mg 200 ppm co-doped Ce:LGGAG single crystals were prepared by micro pulling down method. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of Mg co-doping. Ce4+ charge transfer absorption was observed below 300 nm in Mg,Ce:LGGAG which is in good agreement with previous reports. The scintillation decay times were accelerated by Mg co-doping.

Quenching measurements and modeling of a boron-loaded organic liquid scintillator

DOE PAGES

Westerdale, S.; Xu, J.; Shields, E.; ...

2017-08-03

We present that organic liquid scintillators are used in a wide variety of applications in experimental nuclear and particle physics. Boron-loaded scintillators are particularly useful for detecting neutron captures, due to the high thermal neutron capture cross section of 10B. These scintillators are commonly used in neutron detectors, including the DarkSide-50 neutron veto, where the neutron may produce a signal when it scatters off protons in the scintillator or when it captures on 10B. Reconstructing the energy of these recoils is complicated by scintillation quenching. Understanding how nuclear recoils are quenched in these scintillators is an important and difficult problem.more » In this article, we present a set of measurements of neutron-induced proton recoils in a boron-loaded organic liquid scintillator at recoil energies ranging from 57–467 keV, and we compare these measurements to predictions from different quenching models. We find that a modified Birks' model whose denominator is quadratic in dE/dx best describes the measurements, with χ2/NDF=1.6. In conclusion, this result will help model nuclear recoil scintillation in similar detectors and can be used to improve their neutron tagging efficiency.« less

Quenching measurements and modeling of a boron-loaded organic liquid scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westerdale, S.; Xu, J.; Shields, E.

Organic liquid scintillators are used in a wide variety of applications in experimental nuclear and particle physics. Boron-loaded scintillators are particularly useful for detecting neutron captures, due to the high thermal neutron capture cross section of 10B. These scintillators are commonly used in neutron detectors, including the DarkSide-50 neutron veto, where the neutron may produce a signal when it scatters o protons in the scintillator or when it captures on 10B. Reconstructing the energy of these recoils is complicated by scintillation quenching. Understanding how nuclear recoils are quenched in these scintillators is an important and dicult problem. In this article,more » we present a set of measurements of neutron-induced proton recoils in a boron-loaded organic liquid scintillator at recoil energies ranging from 57-467 keV, and we compare these measurements to predictions from different quenching models. We and that a modified Birks' model whose denominator is quadratic in dE=dx best describes the measurements, with χ 2/NDF = 1:6. This result will help model nuclear recoil scintillation in similar detectors and can be used to improve their neutron tagging efficiency.« less

Quenching measurements and modeling of a boron-loaded organic liquid scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westerdale, S.; Xu, J.; Shields, E.

We present that organic liquid scintillators are used in a wide variety of applications in experimental nuclear and particle physics. Boron-loaded scintillators are particularly useful for detecting neutron captures, due to the high thermal neutron capture cross section of 10B. These scintillators are commonly used in neutron detectors, including the DarkSide-50 neutron veto, where the neutron may produce a signal when it scatters off protons in the scintillator or when it captures on 10B. Reconstructing the energy of these recoils is complicated by scintillation quenching. Understanding how nuclear recoils are quenched in these scintillators is an important and difficult problem.more » In this article, we present a set of measurements of neutron-induced proton recoils in a boron-loaded organic liquid scintillator at recoil energies ranging from 57–467 keV, and we compare these measurements to predictions from different quenching models. We find that a modified Birks' model whose denominator is quadratic in dE/dx best describes the measurements, with χ2/NDF=1.6. In conclusion, this result will help model nuclear recoil scintillation in similar detectors and can be used to improve their neutron tagging efficiency.« less

Quenching measurements and modeling of a boron-loaded organic liquid scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westerdale, S.; Xu, J.; Shields, E.

Organic liquid scintillators are used in a wide variety of applications in experimental nuclear and particle physics. Boron-loaded scintillators are particularly useful for detecting neutron captures, due to the high thermal neutron capture cross section ofmore » $$^{10}$$B. These scintillators are commonly used in neutron detectors, including the DarkSide-50 neutron veto, where the neutron may produce a signal when it scatters off protons in the scintillator or when it captures on $$^{10}$$B. Reconstructing the energy of these recoils is complicated by scintillation quenching. Understanding how nuclear recoils are quenched in these scintillators is an important and difficult problem. In this article, we present a set of measurements of neutron-induced proton recoils in a boron-loaded organic liquid scintillator at recoil energies ranging from 57--467 keV, and we compare these measurements to predictions from different quenching models. We find that a modified Birks' model whose denominator is quadratic in $dE/dx$ best describes the measurements, with $$\\chi^2$$/NDF$=1.6$. This result will help model nuclear recoil scintillation in similar detectors and can be used to improve their neutron tagging efficiency.« less

Investigation of ionospheric scintillation at UKM station, Malaysia during low solar activity

NASA Astrophysics Data System (ADS)

Seif, Aramesh; Abdullah, Mardina; Marie Hasbi, Alina; Zou, Yuhua

2012-12-01

In this paper the investigation of the occurrence of ionospheric scintillation with S4≥0.2 was conducted by using a dual-frequency GISTM (GPS Ionospheric Scintillation and TEC monitor) at Universiti Kebangsaan Malaysia station, Malaysia (2.55°N, 101.46°E; geomagnetic: 7.39°S, 173.63°E) between September 2009 and December 2010. The study shows that significant nighttime amplitude scintillation event with 0.4≤S4<0.6 mainly occurred in the months of March, September and October, while significant daytime amplitude scintillation activity took place in November and December with 0.3≤S4<0.5. Moreover, nighttime amplitude scintillation observed at UKM station always occurred with phase scintillations, total electron content (TEC) depletions, rate of change of TEC (ROT) fluctuations and the enhancement of rate of TEC index (ROTI). Nevertheless, during daytime amplitude scintillation, TEC depletions and ROT fluctuations were much weaker than those that occurred during nighttime and this may be caused by small scale irregularities in the E region, called sporadic-E (Es), while the occurrences of nighttime amplitude scintillation maybe caused by the ionospheric irregularities in the F region.

Time-gated scintillator imaging for real-time optical surface dosimetry in total skin electron therapy.

PubMed

Bruza, Petr; Gollub, Sarah L; Andreozzi, Jacqueline M; Tendler, Irwin I; Williams, Benjamin B; Jarvis, Lesley A; Gladstone, David J; Pogue, Brian W

2018-05-02

The purpose of this study was to measure surface dose by remote time-gated imaging of plastic scintillators. A novel technique for time-gated, intensified camera imaging of scintillator emission was demonstrated, and key parameters influencing the signal were analyzed, including distance, angle and thickness. A set of scintillator samples was calibrated by using thermo-luminescence detector response as reference. Examples of use in total skin electron therapy are described. The data showed excellent room light rejection (signal-to-noise ratio of scintillation SNR  ≈  470), ideal scintillation dose response linearity, and 2% dose rate error. Individual sample scintillation response varied by 7% due to sample preparation. Inverse square distance dependence correction and lens throughput error (8% per meter) correction were needed. At scintillator-to-source angle and observation angle  <50°, the radiant energy fluence error was smaller than 1%. The achieved standard error of the scintillator cumulative dose measurement compared to the TLD dose was 5%. The results from this proof-of-concept study documented the first use of small scintillator targets for remote surface dosimetry in ambient room lighting. The measured dose accuracy renders our method to be comparable to thermo-luminescent detector dosimetry, with the ultimate realization of accuracy likely to be better than shown here. Once optimized, this approach to remote dosimetry may substantially reduce the time and effort required for surface dosimetry.

Time-gated scintillator imaging for real-time optical surface dosimetry in total skin electron therapy

NASA Astrophysics Data System (ADS)

Bruza, Petr; Gollub, Sarah L.; Andreozzi, Jacqueline M.; Tendler, Irwin I.; Williams, Benjamin B.; Jarvis, Lesley A.; Gladstone, David J.; Pogue, Brian W.

2018-05-01

The purpose of this study was to measure surface dose by remote time-gated imaging of plastic scintillators. A novel technique for time-gated, intensified camera imaging of scintillator emission was demonstrated, and key parameters influencing the signal were analyzed, including distance, angle and thickness. A set of scintillator samples was calibrated by using thermo-luminescence detector response as reference. Examples of use in total skin electron therapy are described. The data showed excellent room light rejection (signal-to-noise ratio of scintillation SNR  ≈  470), ideal scintillation dose response linearity, and 2% dose rate error. Individual sample scintillation response varied by 7% due to sample preparation. Inverse square distance dependence correction and lens throughput error (8% per meter) correction were needed. At scintillator-to-source angle and observation angle  <50°, the radiant energy fluence error was smaller than 1%. The achieved standard error of the scintillator cumulative dose measurement compared to the TLD dose was 5%. The results from this proof-of-concept study documented the first use of small scintillator targets for remote surface dosimetry in ambient room lighting. The measured dose accuracy renders our method to be comparable to thermo-luminescent detector dosimetry, with the ultimate realization of accuracy likely to be better than shown here. Once optimized, this approach to remote dosimetry may substantially reduce the time and effort required for surface dosimetry.

Equatorial Scintillation Study at Ilorin and Nsukka, Nigeria during Year 2011-2012

NASA Astrophysics Data System (ADS)

Akala, A.

2017-12-01

This study presents GNSS scintillations over Ilorin (8.48 oN, 4.54 oE, and mag lat: 1.83oS) and Nsukka (6.84 oN, 7.37 oE, and mag lat: 2.94oS), Nigeria during year 2011-2012. The two stations are located within the inner flank of the equatorial ionization anomaly. Firstly, we investigated the climatology of equatorial scintillations at the two stations. We suppressed multipath effects on the data by imposing a 300 elevation masking on the data. In addition, we investigated scintillation occurrences at the two locations on a satellite-by-satellite basis at varying elevation angles. The source of scintillation records at low-elevation angle is attributed to multipath, while that at high-elevation angle is attributed to ionospheric irregularities. Seasonally, scintillations recorded highest occurrences during March equinox, and the least during June solstice. The trend of scintillations, at both low- and high-elevation angles at the two stations were almost the same. EGNOS satellites signals scintillated at the two locations during the time intervals when GPS satellites signals experienced scintillations. These results could support the development of scintillation models for equatorial Africa, and could also be of benefit to GPS and EGNOS service providers and designers, with a view to providing robust services for GNSS user community in Africa.

Metal-loaded organic scintillators for neutrino physics

DOE PAGES

Buck, Christian; Yeh, Minfang

2016-08-03

Organic liquid scintillators are used in many neutrino physics experiments of the past and present. In particular for low energy neutrinos when realtime and energy information are required, liquid scintillators have several advantages compared to other technologies. In many cases the organic liquid needs to be loaded with metal to enhance the neutrino signal over background events. Several metal loaded scintillators of the past suffered from chemical and optical instabilities, limiting the performance of these neutrino detectors. Different ways of metal loading are described in the article with a focus on recent techniques providing metal loaded scintillators that can bemore » used under stable conditions for many years even in ton scale experiments. Lastly, we review applications of metal loaded scintillators in neutrino experiments and compare the performance as well as the prospects of different scintillator types.« less

Study of Sun-Earth interactions using equatorial VHF scintillation in the Indian region

NASA Astrophysics Data System (ADS)

Banola, Sridhar

Plasma density irregularities in the ionosphere (associated with ESF, plasma bubbles and Spo-radic E layers) cause scintillations in various frequency ranges. VHF radio wave scintillation technique is extensively used to study plasma density irregularities of sub-kilometre size . Ef-fects of magnetic and solar activity on ionospheric irregularities are studied so as to ascertain their role in the space weather of the near earth environment in space. Indian Institute of Ge-omagnetism operated a ground network of 13 stations monitoring amplitude scintillations on 244/251 MHz (FLEETSAT 73° E) signals in placecountry-regionIndia for more than a decade under AICPITS. At present VHF scintillation is being recorded at Mumbai by monitoring 251 MHz signal transmitted by geostationary satellite UFO2(71.2 E). sampling at 20 Hz. During CAWSES campaign (March-April 2006, low sunspot period) occurrence of daytime scintilla-tions was observed higher than the nighttime scintillations. This could be due to the fact that during low sunspot years occurrence of spread-F is limited to a narrow latitude region near the dip equator. To study solar cycle association of scintillations, long series of simultaneous amplitude scintillation data for period Jan 1989 to Dec 2000 at Indian low-latitude stations Tirunelveli/Trivandrum, close to dip equator, Pondicherry/Karur, located at the fringe of elec-trojet, Mumbai (dip lat. 13.5o N), a temperate station and Ujjain (dip lat. 18.6o N), close to anomaly crest region are utilized. Nighttime scintillation occurrence is solar activity dependent. Equatorial scintillations are inhibited with increase in geomagnetic activity.

Daytime VHF amplitude scintillations recorded at an Indian low-latitude station, Waltair (17.7°N, 83.3°E) during 1997-2003

NASA Astrophysics Data System (ADS)

Uma, G.; Brahmanandam, P. S.; Srinivasu, V. K. D.; Prasad, D. S. V. V. D.; Rama Rao, P. V. S.

2018-04-01

In this research, it is presented the daytime amplitude scintillations recorded at VHF frequency (244 MHz) at an Indian low-latitude station, Waltair (17.7°N, 83.3°E) during seven continuous years (1997-2003). Contrary to the nighttime scintillation seasonal trends, the occurrence of daytime scintillations maximizes during summer followed by winter and the equinox seasons. The fade depths, scintillation indices and the patch durations of daytime scintillations are meager when compared with their nighttime counterparts. A co-located digital high frequency (HF) ionosonde radar confirms the presence of sporadic (Es) layers when daytime scintillations are observed. The presence of daytime scintillations is evident when the critical frequency of the Es-layer (foEs) is ≥4 MHz and Es-layers are characterized by a highly diffuse range spread Es echoes as can be seen on ionograms. It is surmised that the gradient drift instability (GDI) seems to be the possible mechanism for the generation of these daytime scintillations. It is quite likely that the spread Es-F-layer coupling is done through polarization electric fields (Ep) that develop inside the destabilized patches of sporadic E layers, which are mapped up to the F region along the field lines as to initiate the daytime scintillations through the GDI mechanism. Further, the presence of additional stratification of ionosphere F-layer, popularly known as the F3-layer, is observed on ionograms once the Es-layers and daytime scintillations are ceased.

Induced radioactivity in the blood of cancer patients following Boron Neutron Capture Therapy

PubMed Central

Fujiwara, Keiko; Kinashi, Yuko; Takahashi, Tomoyuki; Yashima, Hiroshi; Kurihara, Kouta; Sakurai, Yoshinori; Tanaka, Hiroki; Ono, Koji; Takahashi, Sentaro

2013-01-01

Since 1990, Boron Neutron Capture Therapy (BNCT) has been used for over 400 cancer patients at the Kyoto University Research Reactor Institute (KURRI). After BNCT, the patients are radioactive and their 24Na and 38Cl levels can be detected via a Na-I scintillation counter. This activity is predominantly due to 24Na, which has a half-life of 14.96 h and thus remains in the body for extended time periods. Radioactive 24Na is mainly generated from 23Na in the target tissue that is exposed to the neutron beam in BNCT. The purpose of this study is to evaluate the relationship between the radioactivity of blood 24Na following BNCT and the absorbed gamma ray dose in the irradiated field. To assess blood 24Na, 1 ml of peripheral blood was collected from 30 patients immediately after the exposure, and the radioactivity of blood 24Na was determined using a germanium counter. The activity of 24Na in the blood correlated with the absorbed gamma ray doses in the irradiated field. For the same absorbed gamma ray dose in the irradiated field, the activity of blood 24Na was higher in patients with neck or lung tumors than in patients with brain or skin tumors. The reasons for these findings are not readily apparent, but the difference in the blood volume and the ratio of bone to soft tissue in the irradiated field, as well as the dose that leaked through the clinical collimator, may be responsible. PMID:23392825

Induced radioactivity in the blood of cancer patients following Boron Neutron Capture Therapy.

PubMed

Fujiwara, Keiko; Kinashi, Yuko; Takahashi, Tomoyuki; Yashima, Hiroshi; Kurihara, Kouta; Sakurai, Yoshinori; Tanaka, Hiroki; Ono, Koji; Takahashi, Sentaro

2013-07-01

Since 1990, Boron Neutron Capture Therapy (BNCT) has been used for over 400 cancer patients at the Kyoto University Research Reactor Institute (KURRI). After BNCT, the patients are radioactive and their (24)Na and (38)Cl levels can be detected via a Na-I scintillation counter. This activity is predominantly due to (24)Na, which has a half-life of 14.96 h and thus remains in the body for extended time periods. Radioactive (24)Na is mainly generated from (23)Na in the target tissue that is exposed to the neutron beam in BNCT. The purpose of this study is to evaluate the relationship between the radioactivity of blood (24)Na following BNCT and the absorbed gamma ray dose in the irradiated field. To assess blood (24)Na, 1 ml of peripheral blood was collected from 30 patients immediately after the exposure, and the radioactivity of blood (24)Na was determined using a germanium counter. The activity of (24)Na in the blood correlated with the absorbed gamma ray doses in the irradiated field. For the same absorbed gamma ray dose in the irradiated field, the activity of blood (24)Na was higher in patients with neck or lung tumors than in patients with brain or skin tumors. The reasons for these findings are not readily apparent, but the difference in the blood volume and the ratio of bone to soft tissue in the irradiated field, as well as the dose that leaked through the clinical collimator, may be responsible.

MSFIA-LOV system for (226)Ra isolation and pre-concentration from water samples previous radiometric detection.

PubMed

Rodríguez, Rogelio; Borràs, Antoni; Leal, Luz; Cerdà, Víctor; Ferrer, Laura

2016-03-10

An automatic system based on multisyringe flow injection analysis (MSFIA) and lab-on-valve (LOV) flow techniques for separation and pre-concentration of (226)Ra from drinking and natural water samples has been developed. The analytical protocol combines two different procedures: the Ra adsorption on MnO2 and the BaSO4 co-precipitation, achieving more selectivity especially in water samples with low radium levels. Radium is adsorbed on MnO2 deposited on macroporous of bead cellulose. Then, it is eluted with hydroxylamine to transform insoluble MnO2 to soluble Mn(II) thus freeing Ra, which is then coprecipitated with BaSO4. The (226)Ra can be directly detected in off-line mode using a low background proportional counter (LBPC) or through a liquid scintillation counter (LSC), after performing an on-line coprecipitate dissolution. Thus, the versatility of the proposed system allows the selection of the radiometric detection technique depending on the detector availability or the required response efficiency (sample number vs. response time and limit of detection). The MSFIA-LOV system improves the precision (1.7% RSD), and the extraction frequency (up to 3 h(-1)). Besides, it has been satisfactorily applied to different types of water matrices (tap, mineral, well and sea water). The (226)Ra minimum detectable activities (LSC: 0.004 Bq L(-1); LBPC: 0.02 Bq L(-1)) attained by this system allow to reach the guidance values proposed by the relevant international agencies e.g. WHO, EPA and EC. Copyright © 2016 Elsevier B.V. All rights reserved.

Angular sensitivities of scintillator slab configurations for location of gamma ray bursts

NASA Technical Reports Server (NTRS)

Gregory, J. C.

1976-01-01

Thin flat scintillator slabs are a useful means of measuring the angular location of gamma ray fluxes of astronomical interest. A statistical estimate of position error was made of two scintillator systems suitable for gamma ray burst location from a balloon or satellite platform. A single rotating scintillator with associated flux monitor is compared with a pair of stationary orthogonal scintillators. Position error for a strong burst is of the order of a few arcmin if systematic errors are ignored.

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

PubMed

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

2014-01-01

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

Very fast doped LaBr.sub.3 scintillators and time-of-flight PET

DOEpatents

Shah, Kanai S.

2006-10-31

The present invention concerns very fast scintillator materials capable of resolving the position of an annihilation event within a portion of a human body cross-section. In one embodiment, the scintillator material comprises LaBr.sub.3 doped with cerium. Particular attention is drawn to LaBr.sub.3 doped with a quantity of Ce that is chosen for improving the timing properties, in particular the rise time and resultant timing resolution of the scintillator, and locational capabilities of the scintillator.

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

NASA Astrophysics Data System (ADS)

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

2013-06-01

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

Skin contamination dosimeter

DOEpatents

Hamby, David M [Corvallis, OR; Farsoni, Abdollah T [Corvallis, OR; Cazalas, Edward [Corvallis, OR

2011-06-21

A technique and device provides absolute skin dosimetry in real time at multiple tissue depths simultaneously. The device uses a phoswich detector which has multiple scintillators embedded at different depths within a non-scintillating material. A digital pulse processor connected to the phoswich detector measures a differential distribution (dN/dH) of count rate N as function of pulse height H for signals from each of the multiple scintillators. A digital processor computes in real time from the differential count-rate distribution for each of multiple scintillators an estimate of an ionizing radiation dose delivered to each of multiple depths of skin tissue corresponding to the multiple scintillators embedded at multiple corresponding depths within the non-scintillating material.

Plastic scintillator enhancement through Quantum Dot

NASA Astrophysics Data System (ADS)

Tam, Alan; Boyraz, Ozdal; Nilsson, Mikael

2017-08-01

Plastic scintillators such as Polyvinyl Toluene (PVT) are used for radiation detection but due to their poor performance they are not widely implemented. In order to circumnavigate this, dopants are added to enhance scintillation by energy transfer otherwise lost through non-radiative processes. In this work, we exploit the effects of energy transfer through the use of short wavelength emission Cadmium Sulfide Quantum Dots (QD) as the transfer stimulant. Scintillation enhancement was observed as Cadmium Sulfide QD with scintillating dyes are embedded in PVT polymer matrix for beta and gamma radiation. Energy transfer was observed between Quantum Dots, scintillating dye, and the host polymer. Different concentrations of QD and 2,5-diphenyloxazole (PPO) dye are investigated to characterize the energy transfer.

Morphology of auroral zone radio wave scintillation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rino, C.L.; Matthews, S.J.

1980-08-01

This paper describes the morphology of midnight sector and morning sector auroral zone scintillation observations made over a two-year period using the Wideband satelite, which is in a sun-synchronous, low-altitude orbit. No definitive seasonal variation was found. The nighttime data showed the highest scintillation ocurrence levels, but significant amounts of morning scintillation were observed. For the most part the scintillation activity followed the general pattern of local magnetic activity. The most prominent feature in the nightime data is a localized amplitude and phase scintillation enhancement at the point where the propagation vector lies within an L shell. A geometrical effectmore » due to a dynamic slab of sheetlike structures in the F region is hypothesized as the source of his enhancement. The data have been sorted by magnetic activity, proximity to local midnight, and season. The general features of the data are in agreement with the accepted morphology of auroral zone scintillation.« less

Tropospheric scintillation prediction models for a high elevation angle based on measured data from a tropical region

NASA Astrophysics Data System (ADS)

Abdul Rahim, Nadirah Binti; Islam, Md. Rafiqul; J. S., Mandeep; Dao, Hassan; Bashir, Saad Osman

2013-12-01

The recent rapid evolution of new satellite services, including VSAT for internet access, LAN interconnection and multimedia applications, has triggered an increasing demand for bandwidth usage by satellite communications. However, these systems are susceptible to propagation effects that become significant as the frequency increases. Scintillation is the rapid signal fluctuation of the amplitude and phase of a radio wave, which is significant in tropical climates. This paper presents the analysis of the tropospheric scintillation data for satellite to Earth links at the Ku-band. Twelve months of data (January-December 2011) were collected and analyzed to evaluate the effect of tropospheric scintillation. Statistics were then further analyzed to inspect the seasonal, worst-month, diurnal and rain-induced scintillation effects. By employing the measured scintillation data, a modification of the Karasawa model for scintillation fades and enhancements is proposed based on data measured in Malaysia.

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

DOE PAGES

Feng, Patrick L; Mengesha, Wondwosen; Anstey, Mitchell R.; ...

2016-02-01

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

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.

Methods for the continuous production of plastic scintillator materials

DOEpatents

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

1999-10-19

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

Gamma ray spectroscopy employing divalent europium-doped alkaline earth halides and digital readout for accurate histogramming

DOEpatents

Cherepy, Nerine Jane; Payne, Stephen Anthony; Drury, Owen B; Sturm, Benjamin W

2014-11-11

A scintillator radiation detector system according to one embodiment includes a scintillator; and a processing device for processing pulse traces corresponding to light pulses from the scintillator, wherein pulse digitization is used to improve energy resolution of the system. A scintillator radiation detector system according to another embodiment includes a processing device for fitting digitized scintillation waveforms to an algorithm based on identifying rise and decay times and performing a direct integration of fit parameters. A method according to yet another embodiment includes processing pulse traces corresponding to light pulses from a scintillator, wherein pulse digitization is used to improve energy resolution of the system. A method in a further embodiment includes fitting digitized scintillation waveforms to an algorithm based on identifying rise and decay times; and performing a direct integration of fit parameters. Additional systems and methods are also presented.

A Review of Ionospheric Scintillation Models.

PubMed

Priyadarshi, S

This is a general review of the existing climatological models of ionospheric radio scintillation for high and equatorial latitudes. Trans-ionospheric communication of radio waves from transmitter to user is affected by the ionosphere which is highly variable and dynamic in both time and space. Scintillation is the term given to irregular amplitude and phase fluctuations of the received signals and related to the electron density irregularities in the ionosphere. Key sources of ionospheric irregularities are plasma instabilities; every irregularities model is based on the theory of radio wave propagation in random media. It is important to understand scintillation phenomena and the approach of different theories. Therefore, we have briefly discussed the theories that are used to interpret ionospheric scintillation data. The global morphology of ionospheric scintillation is also discussed briefly. The most important (in our opinion) analytical and physical models of scintillation are reviewed here.

Plastic scintillators modifications for a selective radiation detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamel, Matthieu; Bertrand, Guillaume H.V.; Carrel, Frederick

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)

Feasibility evaluation of a neutron grating interferometer with an analyzer grating based on a structured scintillator.

PubMed

Kim, Youngju; Kim, Jongyul; Kim, Daeseung; Hussey, Daniel S; Lee, Seung Wook

2018-03-01

We introduce an analyzer grating based on a structured scintillator fabricated by a gadolinium oxysulfide powder filling method for a symmetric Talbot-Lau neutron grating interferometer. This is an alternative way to analyze the Talbot self-image of a grating interferometer without using an absorption grating to block neutrons. Since the structured scintillator analyzer grating itself generates the signal for neutron detection, we do not need an additional scintillator screen as an absorption analyzer grating. We have developed and tested an analyzer grating based on a structured scintillator in our symmetric Talbot-Lau neutron grating interferometer to produce high fidelity absorption, differential phase, and dark-field contrast images. The acquired images have been compared to results of a grating interferometer utilizing a typical absorption analyzer grating with two commercial scintillation screens. The analyzer grating based on the structured scintillator enhances interference fringe visibility and shows a great potential for economical fabrication, compact system design, and so on. We report the performance of the analyzer grating based on a structured scintillator and evaluate its feasibility for the neutron grating interferometer.

Simulation the spatial resolution of an X-ray imager based on zinc oxide nanowires in anodic aluminium oxide membrane by using MCNP and OPTICS Codes

NASA Astrophysics Data System (ADS)

Samarin, S. N.; Saramad, S.

2018-05-01

The spatial resolution of a detector is a very important parameter for x-ray imaging. A bulk scintillation detector because of spreading of light inside the scintillator does't have a good spatial resolution. The nanowire scintillators because of their wave guiding behavior can prevent the spreading of light and can improve the spatial resolution of traditional scintillation detectors. The zinc oxide (ZnO) scintillator nanowire, with its simple construction by electrochemical deposition in regular hexagonal structure of Aluminum oxide membrane has many advantages. The three dimensional absorption of X-ray energy in ZnO scintillator is simulated by a Monte Carlo transport code (MCNP). The transport, attenuation and scattering of the generated photons are simulated by a general-purpose scintillator light response simulation code (OPTICS). The results are compared with a previous publication which used a simulation code of the passage of particles through matter (Geant4). The results verify that this scintillator nanowire structure has a spatial resolution less than one micrometer.

Feasibility evaluation of a neutron grating interferometer with an analyzer grating based on a structured scintillator

NASA Astrophysics Data System (ADS)

Kim, Youngju; Kim, Jongyul; Kim, Daeseung; Hussey, Daniel. S.; Lee, Seung Wook

2018-03-01

We introduce an analyzer grating based on a structured scintillator fabricated by a gadolinium oxysulfide powder filling method for a symmetric Talbot-Lau neutron grating interferometer. This is an alternative way to analyze the Talbot self-image of a grating interferometer without using an absorption grating to block neutrons. Since the structured scintillator analyzer grating itself generates the signal for neutron detection, we do not need an additional scintillator screen as an absorption analyzer grating. We have developed and tested an analyzer grating based on a structured scintillator in our symmetric Talbot-Lau neutron grating interferometer to produce high fidelity absorption, differential phase, and dark-field contrast images. The acquired images have been compared to results of a grating interferometer utilizing a typical absorption analyzer grating with two commercial scintillation screens. The analyzer grating based on the structured scintillator enhances interference fringe visibility and shows a great potential for economical fabrication, compact system design, and so on. We report the performance of the analyzer grating based on a structured scintillator and evaluate its feasibility for the neutron grating interferometer.

Ionospheric Scintillation Induced by Solar Wind Dynamic Pressure Enhancements in the Southern Hemisphere

NASA Astrophysics Data System (ADS)

Coppeans, T.; Zou, S.; Weatherwax, A. T.; Coster, A. J.

2017-12-01

Ionospheric scintillation is the random fluctuation in GPS signal radio waves passing through the ionosphere, a phenomenon that can result in the loss of GPS tracking, but can also reveal information about plasma structures in the ionosphere. Sudden compression of the Earth's magnetosphere by a solar wind dynamic pressure enhancement can cause dramatic changes in the E and F region ionospheric plasma. In this study, we investigate the possible ionospheric scintillation induced by solar wind pressure enhancements using ground-based scintillation receivers located at the McMurdo station and the South Pole station in Antarctica. Various studies of scintillation effects have been carried out, mainly in the northern hemisphere, while the southern hemisphere remains less studied. A pool of storm sudden commencements occurring between Jan. 2011 and Dec. 2014 were sorted based on solar wind dynamic pressure enhancement, background conditions, availability of data, and magnitude of scintillation response. Among the 89 events examined, 14 of them exhibited enhanced scintillation and were selected for detailed examination. Besides the scintillation receivers, other datasets have also been used to carry out the above study, including field-aligned currents from AMPERE, and global GPS TEC. Effects of FACs and TEC/TEC gradients on the generation of these scintillations are studied.

Scintillator for low accelerating voltage scanning electron microscopy imaging

NASA Astrophysics Data System (ADS)

Bowser, Christopher; Tzolov, Marian; Barbi, Nicholas

Scintillators are essential in detecting electrons in SEM. The conventional scintillators such as YAP and YAG have poor response at low accelerating voltages due to a top conductive layer of ITO or Al. We have developed a thin film ZnWO4 scintillator with high photoluminescence quantum efficiency of 60% with enough electrical conductivity to prevent charging. We are showing that the ZnWO4 films are effective in detecting electrons at low accelerating voltages. This makes it a good option for a top layer on crystalline scintillators and we have integrated ZnWO4 with YAP to explore the high response of YAP at high electron energies and the effective response of ZnWO4 at low electron energies. We will compare the spectral intensities over a range of accelerating voltages between 1 and 30kV between the conventional and coupled thin film scintillator. The results are interpreted using a simulation of the depth profile of the electron penetration in the scintillator using CASINO. We have verified the absence of charging by measuring the sum of the secondary and backscattered electron coefficients. We have built detectors with the combined scintillators and we will compare SEM images recorded simultaneously by conventional and ZnWO4-based scintillators.

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

NASA Astrophysics Data System (ADS)

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

2013-05-01

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

Characterizing Properties and Performance of 3D Printed Plastic Scintillators

NASA Astrophysics Data System (ADS)

McCormick, Jacob

2015-10-01

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

Characterizing and simulation the scintillation properties of zinc oxide nanowires in AAO membrane for medical imaging applications

NASA Astrophysics Data System (ADS)

Esfandi, F.; Saramad, S.; Rezaei Shahmirzadi, M.

2017-07-01

In this work, a new method is proposed for extracting some X-ray detection properties of ZnO nanowires electrodeposited on Anodized Aluminum Oxide (AAO) nanoporous template. The results show that the detection efficiency for 12μm thickness of zinc oxide nano scintillator at an energy of 9.8 keV, near the K-edge of ZnO (9.65 keV), is 24%. The X-rays that interact with AAO can also generate electrons that reach the nano scintillator. The scintillation events of these electrons are seen as a low energy tail in the spectrum. In addition, it is found that all the X-rays that are absorbed in 300 nm thickness of the gold layer on the top of the zinc oxide nanowires can participate in the scintillation process with an efficiency of 6%. Hence, the scintillation detection efficiency of the whole detector for 9.8 keV X-ray energy is 30%. The simulation results from Geant4 and the experimental detected photons per MeV energy deposition are also used to extract the light yield of the zinc oxide nano scintillator. The results show that the light yield of the zinc oxide nanowires deposited by the electrochemical method is approximately the same as for single crystal zinc oxide scintillator (9000). Much better spatial resolution of this nano scintillator in comparison to the bulk ones is an advantage which candidates this nano scintillator for medical imaging applications.

An assessment of the application of in situ ion-density data from DMSP to modeling of transionospheric scintillation

NASA Astrophysics Data System (ADS)

Secan, James A.; Reinleitner, Lee A.; Bussey, Robert M.

1990-03-01

Modern military communication, navigation, and surveillance systems depend on reliable, noise-free transionospheric radio frequency channels. They can be severely impacted by small scale electron-density irregularities in the ionosphere, which cause both phase and amplitude scintillation. Basic tools used in planning and mitigation schemes are climatological in nature and thus may greatly over- and under-estimate the effects of scintillation in a given scenario. The results are summarized of a 3 year investigation into the feasibility of using in-situ observations of the ionosphere from the USAF DMSP satellite to calculate estimates of irregularity parameters that could be used to update scintillation models in near real time. Estimates for the level of intensity and phase scintillation on a transionospheric UHF radio link in the early evening auroral zone were calculated from DMSP Scintillation Meter (SM) data and compared to the levels actually observed. The intensity scintillation levels predicted and observed compared quite well, but the comparison with the phase scintillation data was complicated by low-frequency phase noise on the UHF radio link. Results are presented from analysis of DMSP SSIES data collected near Kwajalein Island in conjunction with a propagation-effects experiment. Preliminary conclusions to the assessment study are: (1) the DMSP SM data can be used to make quantitative estimates of the level of scintillation at auroral latitudes, and (2) it may be possible to use the data as a qualitative indicator of scintillation activity levels at equatorial latitudes.

Analysis of the covariance function and aperture averaged fluctuations of irradiance to calculate Cn2

NASA Astrophysics Data System (ADS)

Cauble, Galen D.; Wayne, David T.

2017-09-01

The growth of optical communication has created a need to correctly characterize the atmospheric channel. Atmospheric turbulence along a given channel can drastically affect optical communication signal quality. One means of characterizing atmospheric turbulence is through measurement of the refractive index structure parameter, Cn2. When calculating Cn2 from the scintillation index, σΙ2,the point aperture scintillation index is required. Direct measurement of the point aperture scintillation index is difficult at long ranges due to the light collecting abilities of small apertures. When aperture size is increased past the atmospheric correlation width, aperture averaging decreases the scintillation index below that of the point aperture scintillation index. While the aperture averaging factor can be calculated from theory, it does not often agree with experimental results. Direct measurement of the aperture averaging factor via the pupil plane irradiance covariance function allows conversion from the aperture averaged scintillation index to the point aperture scintillation index. Using a finite aperture, camera, and detector, the aperture averaged scintillation index and aperture averaging factor are measured in parallel and the point aperture scintillation index is calculated. A new instrument built by SSC Pacific was used to collect scintillation data at the Townes Institute Science and Technology Experimentation Facility (TISTEF). This new instrument's data was then compared to BLS900 data. The results show that direct measurement of the aperture averaging factor is achievable using a camera and matches well with groundtruth instrumentation.

Echo scintillation Index affected by cat-eye target's caliber with Cassegrain lens

NASA Astrophysics Data System (ADS)

Shan, Cong-miao; Sun, Hua-yan; Zhao, Yan-zhong; Zheng, Yong-hui

2015-10-01

The optical aperture of cat-eye target has the aperture averaging effect to the active detecting laser of active laser detection system, which can be used to identify optical targets. The echo scintillation characteristics of the transmission-type lens target have been studied in previous work. Discussing the differences of the echo scintillation characteristics between the transmission-type lens target and Cassegrain lens target can be helpful to targets classified. In this paper, the echo scintillation characteristics of Cat-eye target's caliber with Cassegrain lens has been discussed . By using the flashing theory of spherical wave in the weak atmospheric turbulence, the annular aperture filter function and the Kolmogorov power spectrum, the analytic expression of the scintillation index of the cat-eye target echo of the horizontal path two-way transmission was given when the light is normal incidence. Then the impact of turbulence inner and outer scale to the echo scintillation index and the analytic expression of the echo scintillation index at the receiving aperture were presented using the modified Hill spectrum and the modified Von Karman spectrum. Echo scintillation index shows the tendency of decreasing with the target aperture increases and different ratios of the inner and outer aperture diameter show the different echo scintillation index curves. This conclusion has a certain significance for target recognition in the active laser detection system that can largely determine the target type by largely determining the scope of the cat-eye target which depending on echo scintillation index.

Scintillation Effects on Space Shuttle GPS Data

NASA Technical Reports Server (NTRS)

Goodman, John L.; Kramer, Leonard

2001-01-01

Irregularities in ionospheric electron density result in variation in amplitude and phase of Global Positioning System (GPS) signals, or scintillation. GPS receivers tracking scintillated signals may lose carrier phase or frequency lock in the case of phase sc intillation. Amplitude scintillation can cause "enhancement" or "fading" of GPS signals and result in loss of lock. Scintillation can occur over the equatorial and polar regions and is a function of location, time of day, season, and solar and geomagnetic activity. Mid latitude regions are affected only very rarely, resulting from highly disturbed auroral events. In the spring of 1998, due to increasing concern about scintillation of GPS signals during the upcoming solar maximum, the Space Shuttle Program began to assess the impact of scintillation on Collins Miniaturized Airborne GPS Receiver (MAGR) units that are to replace Tactical Air Control and Navigation (TACAN) units on the Space Shuttle orbiters. The Shuttle Program must determine if scintillation effects pose a threat to safety of flight and mission success or require procedural and flight rule changes. Flight controllers in Mission Control must understand scintillation effects on GPS to properly diagnose "off nominal" GPS receiver performance. GPS data from recent Space Shuttle missions indicate that the signals tracked by the Shuttle MAGR manifest scintillation. Scintillation is observed as anomalous noise in velocity measurements lasting for up to 20 minutes on Shuttle orbit passes and are not accounted for in the error budget of the MAGR accuracy parameters. These events are typically coincident with latitude and local time occurrence of previously identified equatorial spread F within about 20 degrees of the magnetic equator. The geographic and seasonal history of these events from ground-based observations and a simple theoretical model, which have potential for predicting events for operational purposes, are reviewed.

L-Band Ionosphere Scintillations Observed by A GNSS Receiver Array at HAARP

NASA Astrophysics Data System (ADS)

Morton, Y.; Pelgrum, W.; van Graas, F.

2011-12-01

As we enter a new solar maximum period, GNSS receivers, especially the ones operating in high latitude and equatorial regions, are facing an increasing threat from ionosphere scintillations. The increased solar activities, however, also offer a great opportunity to collect scintillation data to gain better understandings of scintillation effects on GNSS signals. During the past decade, many GPS receivers have been deployed around the globe to monitor ionosphere scintillations. Most of these GPS receivers are commercial receivers whose tracking mechanisms are not designed to operate under ionosphere scintillation. When strong scintillations occur, these receivers will either generate erroneous outputs or completely lose lock. Even when the scintillation is mild, the tracking loop outputs are not true representation of the signal parameters due the tracking loop transfer function. High quality, unprocessed GNSS receiver front end raw IF samples collected during ionosphere scintillations are necessary to produce realistic scintillation signal parameter estimations. In this presentation, we will update our effort in establishing a unique GNSS receiver array at HAARP, Alaska to collect GPS and GLONASS satellite signals at various stages of the GNSS receiver processing. Signal strength, carrier phase, and relative TEC measurements generated by the receiver array as well as additional on-site diagnostic instrumentation measurements obtained from two active heating experiment campaigns conducted in 2011 will be presented. Additionally, we will also highlight and contrast the artificial heating experiment results with observations of natural scintillation events captured by our receivers using an automatic event trigger mechanism during the past year. These interesting results demonstrate the feasibility and effectiveness of our experimental data collection system in providing insightful details of ionosphere responses to active perturbations and natural disturbances.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duguay-Drouin, P; Delage, ME; Centre Hospitalier University de Quebec, Quebec, QC

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

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:Ce and CsI:Na. We also found an empirical relationship between the Fano factor and the covariance as a function of time between two detectors looking at the same scintillation pulse. This empirical model was used to estimate the Fano factor of LaBr3:Ce and YAP:Ce using the experimentally measured timing-covariance. The estimates of the Fano factor from the time-covariance results were consistent with the estimates of the correlation between the integral signals. We found scintillation light from some scintillators to be sub-Poisson. For the same mean number of total scintillation photons, sub-Poisson light has lower noise. We then conducted a simulation study to investigate whether this low-noise sub-Poisson light can be used to improve spatial resolution. We calculated the Cramer-Rao bound for dierent detector geometries, position of interactions and Fano factors. The Cramer-Rao calculations were veried by generating simulated data and estimating the variance of the maximum likelihood estimator. We found that the Fano factor has no impact on the spatial resolution in gamma-ray imaging systems.

Photonic crystal scintillators and methods of manufacture

DOEpatents

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

2015-08-11

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

Lithium-containing scintillators for thermal neutron, fast neutron, and gamma detection

DOEpatents

Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.

2016-03-01

In one embodiment, a scintillator includes a scintillator material; a primary fluor, and a Li-containing compound, where the Li-containing compound is soluble in the primary fluor, and where the scintillator exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays.

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.

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.

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.

Influence of Depth of Interaction upon the Performance of Scintillator Detectors

PubMed Central

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

2014-01-01

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

Scintillator Design Via Codoping

NASA Astrophysics Data System (ADS)

Melcher, C. L.; Koschan, M.; Zhuravleva, M.; Wu, Y.; Rothfuss, H.; Meng, F.; Tyagi, M.; Donnald, S.; Yang, K.; Hayward, J. P.; Eriksson, L.

Scintillation materials that lack intrinsic luminescence centers must be doped with optically active ions in order to provide luminescent centers that radiatively de-excite as the final step of the scintillation process. Codoping, on the other hand, can be defined as the incorporation of additional specific impurity species usually for the purpose of modifying the scintillation properties, mechanical properties, or the crystal growth behavior. In recent years codoping has become an increasingly popular approach for engineering scintillators with optimal performance for targeted applications. This report reviews several successful examples and its effect on specific properties.

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.

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.

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

NASA Astrophysics Data System (ADS)

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

2016-11-01

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

A study on multifrequency scintillations near the EIA crest of the Indian zone

NASA Astrophysics Data System (ADS)

Chakraborty, S. K.; Chatterjee, S.; Jana, Debasis

2017-10-01

Occurrence features of ionospheric scintillations at S band (2492.028 MHz) are reported for the first time. The same have been explored in the context of scintillations at VHF (250.650 MHz) and L5 (1176.45 MHz) bands. Observations were carried out during the period April-December, 2015 at Raja Peary Mohan College Centre (RPMC: 22.66° N, 88.4° E), located near the equatorial ionization anomaly (EIA) crest of the Indian longitude zone. Mostly weak (<10 dB), short duration, slow fading rate with shallower slope power spectra characterize the S band scintillations compared to VHF and L5 band. In the severe scintillation conditions of VHF frequent loss of lock in L5 channel is reflected. Fade depth of 4.2 ± 1.3 dB and fade rate ∼9 fades/minute at S band mostly precede the loss of lock at L5 channel. A good correspondence between fade rates at multi frequency band is reflected irrespective of phases of scintillation. Spectral analysis reveals weak scattering is the dominating mechanism for scintillation at S band while VHF and L5 band scintillations are mostly attributed to multiple scattering. The estimated threshold coherence length of <23 m at VHF may be suggested to be a good indicator for occurrence of L5 and S band scintillations. Occurrence of simultaneous multi-satellite multi-frequency scintillations leads to speculation over the failsafe navigation using available IRNSS constellation. The results are discussed in terms of existing theory of evolution, structure and dynamics of electron density irregularities in the low latitude region.

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.

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.

Neutron position-sensitive scintillation detector

DOEpatents

Strauss, Michael G.; Brenner, Raul

1984-01-01

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

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.

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.

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.

Determining Light Decay Curves in a Plastic Scintillator using Cosmic Ray Muons

NASA Astrophysics Data System (ADS)

Wakwella, Praveen; Mandanas, Sarah; Wilson, John; Visca, Hannah; Padalino, Stephen; Sangster, T. Craig; Regan, Sean P.

2017-10-01

Plastic scintillators are used in ICF research to measure neutron energies via their time of flight (nToF). The energy resolution and sensitivity of an nToF system is directly correlated with the scintillation decay time of the plastic. To decrease the decay time, some scintillators are quenched with oxygen. Consequently, they become less efficient at producing light. As time passes, oxygen defuses out of the scintillator this in turn increases light production and the decay time. Mono-energetic calibration neutrons produced at accelerator facilities can be used to monitor the decreased oxygen content, however this is a time consuming process and requires that the scintillators be removed from the ICF facilities on a regular basis. Here, a possible method for cross calibrating accelerator neutrons with cosmic ray muons is presented. This method characterizes the scintillator with accelerator-generated neutrons and then cross calibrates them with cosmic ray muons. Once the scintillators are redeployed at the ICF facility the oxygen level can be regularly monitored using muons in situ. Funded in part by the United States Department of Energy through a Grant from the Laboratory for Laser Energetics.

Synthesis and characterization of physical properties of Gd2O2S:Pr3+ semi-nanoflower phosphor

NASA Astrophysics Data System (ADS)

Bagheri, A.; Rezaee Ebrahim Saraee, Kh.; Shakur, H. R.; Zamani Zeinali, H.

2016-05-01

Pure gadolinium oxysulfide phosphor (Gd2O2S) and trivalent praseodymium-doped gadolinium oxysulfide phosphor (Gd2O2S:Pr3+) scintillators with semi-nanoflower crystalline structures were successfully synthesized through a precipitation method and subsequent calcination treatment as a converter for X-ray imaging detectors. The characterization such as the crystal structures and nanostructure of Gd2O2S:Pr3+ scintillator measured by XRD and FeE-SEM experiment. The optical properties of Gd2O2S:Pr3+ scintillator were studied. Luminescence spectra of Gd2O2S:Pr3+ under 320 nm UV excitation show a green emission at near 511 nm corresponding to the 3P0-3H4 of Pr ions. After scintillation properties of synthesized Gd2O2S:Pr3+ scintillator investigated, Gd2O2S:Pr3+ scintillating film fabricated on a glass substrate by a sedimentation method. X-ray imaging of the fabricated scintillators confirmed that the Gd2O2S:Pr3+ scintillator could be used for radiography applications in which good spatial resolution is needed.

Transparent ceramic scintillators for gamma spectroscopy and MeV imaging

NASA Astrophysics Data System (ADS)

Cherepy, N. J.; Seeley, Z. M.; Payne, S. A.; Swanberg, E. L.; Beck, P. R.; Schneberk, D. J.; Stone, G.; Perry, R.; Wihl, B.; Fisher, S. E.; Hunter, S. L.; Thelin, P. A.; Thompson, R. R.; Harvey, N. M.; Stefanik, T.; Kindem, J.

2015-09-01

We report on the development of two new mechanically rugged, high light yield transparent ceramic scintillators: (1) Ce-doped Gd-garnet for gamma spectroscopy, and (2) Eu-doped Gd-Lu-bixbyite for radiography. GYGAG(Ce) garnet transparent ceramics offer ρ = 5.8g/cm3, Zeff = 48, principal decay of <100 ns, and light yield of 50,000 Ph/MeV. Gdgarnet ceramic scintillators offer the best energy resolution of any oxide scintillator, as good as R(662 keV) = 3% (Si-PD readout) for small sizes and typically R(662 keV) < 5% for cubic inch sizes. For radiography, the bixbyite transparent ceramic scintillator, (Gd,Lu,Eu)2O3, or "GLO," offers excellent x-ray stopping, with ρ = 9.1 g/cm3 and Zeff = 68. Several 10" diameter by 0.1" thickness GLO scintillators have been fabricated. GLO outperforms scintillator glass for high energy radiography, due to higher light yield (55,000 Ph/MeV) and better stopping, while providing spatial resolution of >8 lp/mm.

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.

An investigation of methods for updating ionospheric scintillation models using topside in-situ plasma density measurements

NASA Astrophysics Data System (ADS)

Secan, James A.

1991-05-01

Modern military communication, navigation, and surveillance systems depend on reliable, noise-free transionospheric radio-frequency channels. They can be severely impacted by small-scale electron-density irregularities in the ionosphere, which cause both phase and amplitude scintillation. Basic tools used in planning and mitigation schemes are climatological in nature and thus may greatly over- and under-estimate the effects of scintillation in a given scenario. This report summarizes the results of the first year of a three-year investigation into the methods for updating ionospheric scintillation models using observations of ionospheric plasma-density irregularities measured by DMSP Scintillation Meter (SM) sensor. Results are reported from the analysis of data from a campaign conducted in January 1990 near Tromso, Norway, in which near coincident in-situ plasma-density and transionospheric scintillation measurements were made. Estimates for the level of intensity and phase scintillation on a transionospheric UHF radio link in the early-evening auroral zone were calculated from DMSP SM data and compared to the levels actually observed.