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Title: Detectors for Active Interrogation Applications

Active interrogation creates an environment that is particularly challenging from a radiation-detection standpoint: the elevated background levels from the source can mask the desired signatures from the SNM. Neutron based interrogation experiments have shown that nanosecond-level timing is required to discriminate induced-fission neutrons from the scattered source neutrons. Previous experiments using high-energy bremsstrahlung X-rays have demonstrated the ability to induce and detect prompt photofission neutrons from single target materials; however, a real-world application would require spectroscopic capability to discern between photofission neutrons emitted by SNM and neutrons emitted by other reactions in non-SNM. Using digital pulseshape discrimination, organic liquid scintillators are capable of reliably detecting neutrons in an intense gamma-ray field. Photon misclassification rates as low as 1 in 10 6 have been achieved, which is approaching the level of gaseous neutron detectors such as 3He without the need for neutron moderation. These scintillators also possess nanosecond-timing resolution, making them candidates for both neutron-and photon-driven active interrogation systems. Lastly, we have applied an array of liquid and NaI(Tl) scintillators to successfully image 13.7 kg of HEU interrogated by a DT neutron generator; the system was in the direct presence of the accelerator during the experiment.
Authors:
 [1] ;  [1] ;  [1] ;  [1]
  1. Univ. of Michigan, Ann Arbor, MI (United States). Nuclear Engineering and Radiological Sciences
Publication Date:
Grant/Contract Number:
NA0002534
Type:
Accepted Manuscript
Journal Name:
Physics Procedia
Additional Journal Information:
Journal Volume: 90; Journal Issue: C; Journal ID: ISSN 1875-3892
Publisher:
Elsevier
Research Org:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org:
USDOE NA Office of Nonproliferation and Verification Research and Development (NA-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Organic scintillator; active interrogation; neutron imaging
OSTI Identifier:
1454802

Clarke, S. D., Hamel, M. C., Bourne, M. M., and Pozzi, S. A.. Detectors for Active Interrogation Applications. United States: N. p., Web. doi:10.1016/j.phpro.2017.09.006.
Clarke, S. D., Hamel, M. C., Bourne, M. M., & Pozzi, S. A.. Detectors for Active Interrogation Applications. United States. doi:10.1016/j.phpro.2017.09.006.
Clarke, S. D., Hamel, M. C., Bourne, M. M., and Pozzi, S. A.. 2017. "Detectors for Active Interrogation Applications". United States. doi:10.1016/j.phpro.2017.09.006. https://www.osti.gov/servlets/purl/1454802.
@article{osti_1454802,
title = {Detectors for Active Interrogation Applications},
author = {Clarke, S. D. and Hamel, M. C. and Bourne, M. M. and Pozzi, S. A.},
abstractNote = {Active interrogation creates an environment that is particularly challenging from a radiation-detection standpoint: the elevated background levels from the source can mask the desired signatures from the SNM. Neutron based interrogation experiments have shown that nanosecond-level timing is required to discriminate induced-fission neutrons from the scattered source neutrons. Previous experiments using high-energy bremsstrahlung X-rays have demonstrated the ability to induce and detect prompt photofission neutrons from single target materials; however, a real-world application would require spectroscopic capability to discern between photofission neutrons emitted by SNM and neutrons emitted by other reactions in non-SNM. Using digital pulseshape discrimination, organic liquid scintillators are capable of reliably detecting neutrons in an intense gamma-ray field. Photon misclassification rates as low as 1 in 106 have been achieved, which is approaching the level of gaseous neutron detectors such as 3He without the need for neutron moderation. These scintillators also possess nanosecond-timing resolution, making them candidates for both neutron-and photon-driven active interrogation systems. Lastly, we have applied an array of liquid and NaI(Tl) scintillators to successfully image 13.7 kg of HEU interrogated by a DT neutron generator; the system was in the direct presence of the accelerator during the experiment.},
doi = {10.1016/j.phpro.2017.09.006},
journal = {Physics Procedia},
number = C,
volume = 90,
place = {United States},
year = {2017},
month = {10}
}