Gamma-ray and fast neutron imager with thermal neutron detection capability for detecting shielded and bare nuclear materials

2015 ◽  
Author(s):  
Andreas Enqvist ◽  
Adam Veige ◽  
James K. Walker ◽  
Richard Farley ◽  
Young Noh
Keyword(s):  
Thermal Neutron ◽  
Fast Neutron ◽  
Gamma Ray ◽  
Neutron Detection ◽  
Nuclear Materials ◽  
Detection Capability

Growth and scintillation properties of LiBr/CeBr3 eutectic scintillator for neutron detection

2021 ◽  
Author(s):  
Ryuga Yajima ◽  
Kei Kamada ◽  
Yui Takizawa ◽  
Masao Yoshino ◽  
Kyoung Jin Kim ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Gamma Ray ◽  
Neutron Detection ◽  
Eutectic Structure ◽  
Growth Direction ◽  
Emission Peak ◽  
Molar Ratio ◽  
X Ray ◽  
Vertical Bridgman ◽  
Lamellar Type

Abstract The 6LiBr/CeBr3 eutectic scintillator for thermal neutron detection has been developed due to achieving high 6Li concentration. The eutectics were grown by vertical Bridgman method. Molar ratio of 6Li in 6LiBr/CeBr3 eutectic is 35 %, which is higher than that of commercial neutron scintillators such Ce:LiCaAlF6 and Ce:Cs2LiYCl6. The grown eutectic had lamellar-type eutectic structure extending along the growth direction and optical transparency. The grown eutectics showed an emission peak at 360 and 380 nm ascribed to Ce3+ 4f-5d transition from CeBr3 scintillation phase. The measurements of scintillation performance of the 6LiBr/CeBr3 were performed using x-ray, gamma-ray and neutron irradiation to evaluate its potential as a neutron scintillator.

A method for determining density based on gamma ray and fast neutron detection using a Cs2LiYCl6 detector in neutron-gamma density logging

2018 ◽  
Vol 142 ◽  
pp. 77-84 ◽  
Author(s):  
Quanying Zhang ◽  
Feng Zhang ◽  
Robin P. Gardner ◽  
Huizhong Yan ◽  
Guoli Wu ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Gamma Ray ◽  
Neutron Detection ◽  
Gamma Density ◽  
Fast Neutron Detection

scholarly journals Thin Film Polymer Composite Scintillators for Thermal Neutron Detection

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Andrew N. Mabe ◽  
John D. Auxier ◽  
Matthew J. Urffer ◽  
Stephen A. Young ◽  
Dayakar Penumadu ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Neutron ◽  
Gamma Ray ◽  
Detection Efficiency ◽  
Fluorescence Emission ◽  
Neutron Detection ◽  
Fluorescent Sensors ◽  
Neutron Detectors ◽  
Neutron Detection Efficiency ◽  
Film Polymer

Thin film polystyrene composite scintillators containing LiF6 and organic fluors have been fabricated and tested as thermal neutron detectors. Varying fluorescence emission intensities for different compositions are interpreted in terms of the Beer-Lambert law and indicate that the sensitivity of fluorescent sensors can be improved by incorporating transparent particles with refractive index different than that of the polymer matrix. Compositions and thicknesses were varied to optimize the fluorescence and thermal neutron response and to reduce gamma-ray sensitivity. Neutron detection efficiency and neutron/gamma-ray discrimination are reported herein as functions of composition and thickness. Gamma-ray sensitivity is affected largely by changing thickness and unaffected by the amount of LiF6 in the film. The best neutron/gamma-ray discrimination characteristics are obtained for film thicknesses in the range 25–150 μm.

scholarly journals THE USE OF FAST NEUTRON DETECTION FOR MATERIALS ACCOUNTABILITY

2014 ◽  
Vol 27 ◽  
pp. 1460140 ◽  
Author(s):  
L. F. NAKAE ◽  
G. F. CHAPLINE ◽  
A. M. GLENN ◽  
P. L. KERR ◽  
K. S. KIM ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Fast Neutron ◽  
Liquid Scintillator ◽  
Neutron Detection ◽  
Nuclear Material ◽  
Detector Response ◽  
Surprising Result ◽  
Neutron Detectors ◽  
Detection Techniques ◽  
Fast Neutron Detection

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 3 He ) 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 3 He counters measuring correlated pairs in modest (kg) samples of plutonium.

scholarly journals Thermal neutron detection using thin PEN film doped with high cross section materials

Energetika ◽  
2017 ◽  
Vol 63 (3) ◽  
Author(s):  
Jevgenij Garankin ◽  
Artūras Plukis ◽  
Elena Lagzdina
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Energy Deposition ◽  
Gamma Ray ◽  
Recoil Proton ◽  
Neutron Cross Section ◽  
Neutron Detection ◽  
Deep Blue ◽  
Neutron Reaction ◽  
Poly Ethylene

Poly(ethylene 2,6-naphthalate) (PEN) is promising as a new plastic scintillator, which emits deep-blue photons. Its photoluminescence emission peak (434–436 nm) and the decay time is of the order of 3 ns, as well as it is resistant to harsh environment. In this study, thin PEN film with high neutron cross section dopants was used for the thermal neutron detection. Iron boride, lithium tetraborate and lithium metaborate layers were coated on a 125 µm PEN film. Reaction particles from the boron neutron and lithium neutron reaction were detected by scintillation in PEN, and photomultiplier (PMT) pulses were registered and analysed. Energy deposition in the film samples was calculated using MCNP6 code taking into account losses in the source and air gap for the alpha particle source and incomplete energy deposition for the electrons. It was found that a small quantity of particles from the thermal neutron reaction could be detected in the strong neutron, gamma ray and recoil proton background.

Fast neutron detection under intense gamma-ray fields with novel nuclear emulsion technique

2013 ◽  
Vol 55 ◽  
pp. 79-82 ◽  
Author(s):  
K. Ishihara ◽  
K. Takagi ◽  
H. Minato ◽  
J. Kawarabayashi ◽  
H. Tomita ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Nuclear Emulsion ◽  
Gamma Ray ◽  
Neutron Detection ◽  
Emulsion Technique ◽  
Fast Neutron Detection

INVESTIGATION OF NUCLEAR EMULSIONS IN TERMS OF NEUTRON DOSIMETRY

2019 ◽  
Vol 186 (2-3) ◽  
pp. 229-234
Author(s):  
Martina Lužová ◽  
Andrei A Zaitsev ◽  
Věra Bradnová ◽  
Iva Ambrožová ◽  
Martin Kákona ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Fast Neutron ◽  
Silver Halide ◽  
Neutron Detection ◽  
Neutron Dosimetry ◽  
Nuclear Emulsions ◽  
Neutron Fluences ◽  
Fast Neutron Detection ◽  
Personal Dosimetry

Abstract Neutron detection using nuclear emulsions can offer an alternative in personal dosimetry. The production of emulsions and their quality have to be well controlled with respect to their application in dosimetry. Nuclear emulsions consist mainly of gelatin and silver halide. Gelatin contains a significant amount of hydrogen, which can be used for fast neutron detection. The addition of B-10 in the emulsion is convenient for thermal neutron detection. In this paper, standard nuclear emulsions BR-2 and nuclear emulsions BR-2 enriched with boron produced at the Slavich Company, Russia, were applied for evaluation of fast and thermal neutron fluences. The results were obtained by calculation from the presumed emulsion composition without prior calibration. Evidence that nuclear emulsions used in the experiment are suitable for neutron dosimetry is provided.

scholarly journals Investigation of thermal neutron detection capability of a CdZnTe detector in a mixed gamma-neutron radiation field

Nukleonika ◽  
2018 ◽  
Vol 63 (3) ◽  
pp. 59-64
Author(s):  
Haluk Yücel ◽  
R. Bora Narttürk ◽  
Senem Zümrüt ◽  
Gizem Gedik ◽  
Mustafa Karadag
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Radiation Field ◽  
Epithermal Neutron ◽  
Gamma Ray ◽  
Neutron Detection ◽  
Neutron Radiation ◽  
Detection Sensitivity ◽  
Shielding Effect ◽  
Cdznte Detector

Abstract The aim of this study was to investigate the thermal neutron measurement capability of a CdZnTe detector irradiated in a mixed gamma-neutron radiation field. A CdZnTe detector was irradiated in one of the irradiation tubes of a 241Am-Be source unit to determine the sensitivity factors of the detector in terms of peak count rate (counts per second [cps]) per neutron flux (in square centimeters per second) [cps/neutron·cm−2·s−1]. The CdZnTe detector was covered in a 1-mm-thick cadmium (Cd) cylindrical box to completely absorb incoming thermal neutrons via 113Cd(n,γ) capture reactions. To achieve, this Cd-covered CdZnTe detector was placed in a well-thermalized neutron field (f-ratio = 50.9 ± 1.3) in the irradiation tube of the 241Am-Be neutron source. The gamma-ray spectra were acquired, and the most intense gamma-ray peak at 558 keV (0.74 γ/n) was evaluated to estimate the thermal neutron flux. The epithermal component was also estimated from the bare CdZnTe detector irradiation because the epithermal neutron cutoff energy is about 0.55 eV at the 1-mm-thick Cd filter. A high-density polyethylene moderating cylinder box can also be fitted into the Cd filter box to enhance thermal sensitivity because of moderation of the epithermal neutron component. Neutron detection sensitivity was determined from the measured count rates from the 558 keV photopeak, using the measured neutron fluxes at different irradiation positions. The results indicate that the CdZnTe detector can serve as a neutron detector in mixed gamma-neutron radiation fields, such as reactors, neutron generators, linear accelerators, and isotopic neutron sources. New thermal neutron filters, such as Gd and Tb foils, can be tested instead of the Cd filter due to its serious gamma-shielding effect.

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