Characterization of GS20 and CLYC Detectors for Neutron Resonance Transmission Analysis in High Radiation Environments

Fuente: arXiv
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Auteurs principaux: Subzwari, Shayaan, McDonald, Benjamin, Danagoulian, Areg
Format: Preprint
Publié: 2026
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author Subzwari, Shayaan
McDonald, Benjamin
Danagoulian, Areg
author_facet Subzwari, Shayaan
McDonald, Benjamin
Danagoulian, Areg
contents Advanced reactor concepts based on the thorium fuel cycle offer several advantages over conventional uranium-fueled systems, but they also stress-test the existing NDA toolbox for international safeguards. In particular, the presence of 232U and its ~MeV gamma-emitting daughters in thorium-based spent fuel creates a harsh radiological environment that complicates gamma-based active interrogation safeguard techniques. NRTA has emerged as a promising safeguards technique due to its isotopic specificity in the epithermal range and its robustness against non-resonant shielding. However, deploying NRTA in thorium safeguards requires neutron detectors that maintain timing performance and quantitative accuracy in intense gamma fields. This paper reports a comparative characterization of two candidate detectors for portable NRTA: GS20 and CLYC. GS20 has already been demonstrated as an effective epithermal detector in portable NRTA systems but offers limited neutron--gamma discrimination. CLYC, by contrast, provides strong pulse-shape discrimination (PSD) but has a much longer scintillation decay time and includes 133Cs, whose resonances partially overlap with key actinide resonances in the epithermal region. Using a DT-driven NRTA setup with a 2 m flight path, we compare GS20 and CLYC in measurements of a 1.50 mm tungsten target under both ``clean'' conditions and in an artificially constructed high gamma-radiation environment produced by an auxiliary source as a way of emulating a highly radioactive 233U target. The results indicate that CLYC, despite its long decay time, provides significantly more precise NRTA measurements in high radiation environments than GS20. For thorium-based safeguards scenarios where 233U must be identified and quantified in the presence of intense gamma backgrounds, CLYC-like detectors with strong PSD appear to be the more reliable choice.
format Preprint
id arxiv_https___arxiv_org_abs_2604_04381
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Characterization of GS20 and CLYC Detectors for Neutron Resonance Transmission Analysis in High Radiation Environments
Subzwari, Shayaan
McDonald, Benjamin
Danagoulian, Areg
Instrumentation and Detectors
Nuclear Experiment
Physics and Society
Advanced reactor concepts based on the thorium fuel cycle offer several advantages over conventional uranium-fueled systems, but they also stress-test the existing NDA toolbox for international safeguards. In particular, the presence of 232U and its ~MeV gamma-emitting daughters in thorium-based spent fuel creates a harsh radiological environment that complicates gamma-based active interrogation safeguard techniques. NRTA has emerged as a promising safeguards technique due to its isotopic specificity in the epithermal range and its robustness against non-resonant shielding. However, deploying NRTA in thorium safeguards requires neutron detectors that maintain timing performance and quantitative accuracy in intense gamma fields. This paper reports a comparative characterization of two candidate detectors for portable NRTA: GS20 and CLYC. GS20 has already been demonstrated as an effective epithermal detector in portable NRTA systems but offers limited neutron--gamma discrimination. CLYC, by contrast, provides strong pulse-shape discrimination (PSD) but has a much longer scintillation decay time and includes 133Cs, whose resonances partially overlap with key actinide resonances in the epithermal region. Using a DT-driven NRTA setup with a 2 m flight path, we compare GS20 and CLYC in measurements of a 1.50 mm tungsten target under both ``clean'' conditions and in an artificially constructed high gamma-radiation environment produced by an auxiliary source as a way of emulating a highly radioactive 233U target. The results indicate that CLYC, despite its long decay time, provides significantly more precise NRTA measurements in high radiation environments than GS20. For thorium-based safeguards scenarios where 233U must be identified and quantified in the presence of intense gamma backgrounds, CLYC-like detectors with strong PSD appear to be the more reliable choice.
title Characterization of GS20 and CLYC Detectors for Neutron Resonance Transmission Analysis in High Radiation Environments
topic Instrumentation and Detectors
Nuclear Experiment
Physics and Society
url https://arxiv.org/abs/2604.04381