TY - JOUR
T1 - Low-resolution gamma-ray spectrometry for an information barrier based on a multi-criteria template-matching approach
AU - Göttsche, Malte
AU - Schirm, Janet
AU - Glaser, Alexander
N1 - Funding Information:
In the course of this project, we used more than two decades of single-CPU computer time. The authors thank the team of Princeton University's High Performance Cluster for their support. We also thank John Mattingly for valuable feedback on our modeling approach. This work is supported by the Consortium for Verification Technology (CVT) under Department of Energy National Nuclear Security Administration Award DE-NA 0002534 . Experimental results shown in Fig. 3 were obtained in measurements organized by the CVT at the Device Assembly Facility at the Nevada National Security Site in July 2016.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/12/21
Y1 - 2016/12/21
N2 - Gamma-ray spectrometry has been successfully employed to identify unique items containing special nuclear materials. Template information barriers have been developed in the past to confirm items as warheads by comparing their gamma signature to the signature of true warheads. Their development has, however, not been fully transparent, and they may not be sensitive to some relevant evasion scenarios. We develop a fully open template information barrier concept, based on low-resolution measurements, which, by design, reduces the extent of revealed sensitive information. The concept is based on three signatures of an item to be compared to a recorded template. The similarity of the spectrum is assessed by a modification of the Kolmogorov–Smirnov test to confirm the isotopic composition. The total gamma count rate must agree with the template as a measure of the projected surface of the object. In order to detect the diversion of fissile material from the interior of an item, a polyethylene mask is placed in front of the detector. Neutrons from spontaneous and induced fission events in the item produce 2.223 MeV gamma rays from neutron capture by hydrogen-1 in the mask. This peak is detected and its intensity scales with the item's fissile mass. The analysis based on MCNP Monte Carlo simulations of various plutonium configurations suggests that this concept can distinguish a valid item from a variety of invalid ones. The concept intentionally avoids any assumptions about specific spectral features, such as looking for specific gamma peaks of specific isotopes, thereby facilitating a fully unclassified discussion. By making all aspects public and allowing interested participants to contribute to the development and benchmarking, we enable a more open and inclusive discourse on this matter.
AB - Gamma-ray spectrometry has been successfully employed to identify unique items containing special nuclear materials. Template information barriers have been developed in the past to confirm items as warheads by comparing their gamma signature to the signature of true warheads. Their development has, however, not been fully transparent, and they may not be sensitive to some relevant evasion scenarios. We develop a fully open template information barrier concept, based on low-resolution measurements, which, by design, reduces the extent of revealed sensitive information. The concept is based on three signatures of an item to be compared to a recorded template. The similarity of the spectrum is assessed by a modification of the Kolmogorov–Smirnov test to confirm the isotopic composition. The total gamma count rate must agree with the template as a measure of the projected surface of the object. In order to detect the diversion of fissile material from the interior of an item, a polyethylene mask is placed in front of the detector. Neutrons from spontaneous and induced fission events in the item produce 2.223 MeV gamma rays from neutron capture by hydrogen-1 in the mask. This peak is detected and its intensity scales with the item's fissile mass. The analysis based on MCNP Monte Carlo simulations of various plutonium configurations suggests that this concept can distinguish a valid item from a variety of invalid ones. The concept intentionally avoids any assumptions about specific spectral features, such as looking for specific gamma peaks of specific isotopes, thereby facilitating a fully unclassified discussion. By making all aspects public and allowing interested participants to contribute to the development and benchmarking, we enable a more open and inclusive discourse on this matter.
KW - Gamma-ray spectrometry
KW - Information barrier
KW - Nuclear arms control
KW - Nuclear disarmament
KW - Nuclear warhead verification
KW - Prompt-gamma activation analysis
KW - Template approach
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U2 - 10.1016/j.nima.2016.10.013
DO - 10.1016/j.nima.2016.10.013
M3 - Article
AN - SCOPUS:84991712211
SN - 0168-9002
VL - 840
SP - 139
EP - 144
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
ER -