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Title: Effects of Correlated and Uncorrelated Gamma Rays on Neutron Multiplicity Counting

Abstract

Neutron multiplicity counting relies on time correlation between neutron events to assay the fissile mass, (α,n) to spontaneous fission neutron ratio, and neutron self-multiplication of samples. Gamma-ray sensitive neutron multiplicity counters may misidentify gamma rays as neutrons and therefore miscalculate sample characteristics. Time correlated and uncorrelated gamma-ray-like signals were added into gamma-ray free neutron multiplicity counter data to examine the effects of gamma ray signals being misidentified as neutron signals on assaying sample characteristics. Multiplicity counter measurements with and without gamma-ray-like signals were compared to determine the assay error associated with gamma-ray-like signals at various gamma-ray and neutron rates. Correlated and uncorrelated gamma-ray signals each produced consistent but different measurement errors. Correlated gamma-ray signals most strongly led to fissile mass overestimates, whereas uncorrelated gamma-ray signals most strongly lead to (α,n) neutron overestimates. Gamma-ray sensitive neutron multiplicity counters may be able to account for the effects of gamma-rays on measurements to mitigate measurement uncertainties.

Authors:
ORCiD logo; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20)
OSTI Identifier:
1415075
Report Number(s):
PNNL-SA-119140
Journal ID: ISSN 0018-9499; DN2001000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Transactions on Nuclear Science; Journal Volume: 64; Journal Issue: 7
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; coincidence counting; gamma-rays detection; gamma-ray effects; multiplicity counting; neutrons; time correlated; uncorrelated

Citation Formats

Cowles, Christian C., Behling, Richard S., Imel, George R., Kouzes, Richard T., Lintereur, Azaree T., Robinson, Sean M., Siciliano, Edward R., and Stave, Sean C. Effects of Correlated and Uncorrelated Gamma Rays on Neutron Multiplicity Counting. United States: N. p., 2017. Web. doi:10.1109/TNS.2017.2667407.
Cowles, Christian C., Behling, Richard S., Imel, George R., Kouzes, Richard T., Lintereur, Azaree T., Robinson, Sean M., Siciliano, Edward R., & Stave, Sean C. Effects of Correlated and Uncorrelated Gamma Rays on Neutron Multiplicity Counting. United States. doi:10.1109/TNS.2017.2667407.
Cowles, Christian C., Behling, Richard S., Imel, George R., Kouzes, Richard T., Lintereur, Azaree T., Robinson, Sean M., Siciliano, Edward R., and Stave, Sean C. Sat . "Effects of Correlated and Uncorrelated Gamma Rays on Neutron Multiplicity Counting". United States. doi:10.1109/TNS.2017.2667407.
@article{osti_1415075,
title = {Effects of Correlated and Uncorrelated Gamma Rays on Neutron Multiplicity Counting},
author = {Cowles, Christian C. and Behling, Richard S. and Imel, George R. and Kouzes, Richard T. and Lintereur, Azaree T. and Robinson, Sean M. and Siciliano, Edward R. and Stave, Sean C.},
abstractNote = {Neutron multiplicity counting relies on time correlation between neutron events to assay the fissile mass, (α,n) to spontaneous fission neutron ratio, and neutron self-multiplication of samples. Gamma-ray sensitive neutron multiplicity counters may misidentify gamma rays as neutrons and therefore miscalculate sample characteristics. Time correlated and uncorrelated gamma-ray-like signals were added into gamma-ray free neutron multiplicity counter data to examine the effects of gamma ray signals being misidentified as neutron signals on assaying sample characteristics. Multiplicity counter measurements with and without gamma-ray-like signals were compared to determine the assay error associated with gamma-ray-like signals at various gamma-ray and neutron rates. Correlated and uncorrelated gamma-ray signals each produced consistent but different measurement errors. Correlated gamma-ray signals most strongly led to fissile mass overestimates, whereas uncorrelated gamma-ray signals most strongly lead to (α,n) neutron overestimates. Gamma-ray sensitive neutron multiplicity counters may be able to account for the effects of gamma-rays on measurements to mitigate measurement uncertainties.},
doi = {10.1109/TNS.2017.2667407},
journal = {IEEE Transactions on Nuclear Science},
number = 7,
volume = 64,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}