scholarly journals A DEPLOYABLE FAST-NEUTRON CODED-APERTURE IMAGER FOR QUANTIFYING NUCLEAR MATERIAL

2013 ◽  
Author(s):  
Paul Hausladen ◽  
Jason Newby ◽  
J Felix Liang ◽  
Matthew A Blackston
Keyword(s):  
Fast Neutron ◽  
Nuclear Material ◽  
Coded Aperture

Nuclear Material Measurement Based on Fast Neutron Multiplicity Counter

2020 ◽  
Author(s):  
Xianghua Su ◽  
Quanhu Zhang ◽  
Suxia Hou ◽  
Sufen Li ◽  
Jianqing Yang ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Detection Efficiency ◽  
Mass Range ◽  
Nuclear Material ◽  
Neutron Multiplicity ◽  
Analytical Equation ◽  
Analysis Method ◽  
Sample Mass ◽  
Mechanism Of Interaction ◽  
Non Destructive

Abstract Fast neutron multiplicity counting (FNMC) analysis method, as a new non-destructive analysis method for nuclear materials, plays an increasingly important role in the measurement of nuclear material properties. Based on the derivation of the FNMC analytical equation of Pu material, the method of solving the sample parameters was given. By analyzing the mechanism of interaction of neutrons and matter, the model used by Geant4 (version 10.4) software was determined, and a set of three-layer, fast neutron multiplicity counters with six liquid scintillation detectors per layer was constructed. Using the fast neutron multiplicity counter to analyze the measured parameters, the detection efficiency variation was less than 0.4% within the 150g sample mass range, and the PuO2 fluctuation was less than the metal Pu. By studying the detection efficiency and the multiplicity counting rate as a function of sample mass, within the 150g sample mass range, both basically meet the model assumptions of the FNMC analytical equation. The metal Pu and PuO2 samples were set separately, and the FNMC analysis equation was solved. When the sample mass was within 150g, the sample mass solution deviation was less than 10%. The results show that the built-in fast neutron multiplicity counter can better measure Pu sample properties.

Fast neutron interrogation of special nuclear material using differential die-away technique

2021 ◽  
pp. 109896
Author(s):  
Tushar Roy ◽  
Yogesh Kashyap ◽  
Mayank Shukla ◽  
Prashant Singh ◽  
Ravi Baribaddala
Keyword(s):  
Fast Neutron ◽  
Nuclear Material ◽  
Neutron Interrogation

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.

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