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Title: Fast Neutron Sensitivity with HPGe

Abstract

In addition to being excellent gamma-ray detectors, germanium detectors are also sensitive to fast neutrons. Incident neutrons undergo inelastic scattering {Ge(n,n')Ge*} off germanium nuclei and the resulting excited states emit gamma rays or conversion electrons. The response of a standard 140% high-purity germanium (HPGe) detector with a bismuth germanate (BGO) anti-coincidence shield was measured for several neutron sources to characterize the ability of the HPGe detector to detect fast neutrons. For a sensitivity calculation performed using the characteristic fast neutron response peak that occurs at 692 keV, the 140% germanium detector system exhibited a sensitivity of ~175 counts / kg of WGPu metal in 1000 seconds at a source-detector distance of 1 meter with 4 in. of lead shielding between source and detector. Theoretical work also indicates that it might be possible to use the shape of the fast-neutron inelastic scattering signatures (specifically, the end-point energy of the long high energy tail of the resulting asymmetric peak) to gain additional information about the energy distribution of the incident neutron spectrum. However, the experimentally observed end-point energies appear to be almost identical for each of the fast neutron sources counted. Detailed MCNP calculations show that the neutron energy distributions impingent onmore » the detector for these sources are very similar in this experimental configuration, due to neutron scattering in a lead shield (placed between the neutron source and HPGe detector to reduce the gamma ray flux), the BGO anti-coincidence detector, and the concrete floor.« less

Authors:
 [1];  [1];  [1];  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
946671
Report Number(s):
PNNL-SA-58127
Journal ID: ISSN 1095-7863; DP4011020; TRN: US0900990
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Conference
Journal Name:
Nuclear Science Symposium Conference Record, 2007. NSS 07'. IEEE
Additional Journal Information:
Journal Volume: 2; Conference: 2007 IEEE Nuclear Science Symposium Conference Record, Honolulu, HI (United States), 26 Oct-3 Nov 2007; Journal ID: ISSN 1095-7863
Publisher:
IEEE Service Center, Piscataway, NJ, United States
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BISMUTH GERMANATES; CONCRETES; CONFIGURATION; ELECTRONS; ENERGY SPECTRA; EXCITED STATES; FAST NEUTRONS; GE SEMICONDUCTOR DETECTORS; GERMANIUM; INELASTIC SCATTERING; NEUTRON SOURCES; NEUTRONS; NUCLEI; SCATTERING; SENSITIVITY; SHAPE; SHIELDING; SHIELDS; HPGe; fast neutron; spectroscopy

Citation Formats

Seifert, Allen, Hensley, Walter K., Siciliano, Edward R., and Pitts, W. K. Fast Neutron Sensitivity with HPGe. United States: N. p., 2008. Web. doi:10.1109/NSSMIC.2007.4437216.
Seifert, Allen, Hensley, Walter K., Siciliano, Edward R., & Pitts, W. K. Fast Neutron Sensitivity with HPGe. United States. https://doi.org/10.1109/NSSMIC.2007.4437216
Seifert, Allen, Hensley, Walter K., Siciliano, Edward R., and Pitts, W. K. Tue . "Fast Neutron Sensitivity with HPGe". United States. https://doi.org/10.1109/NSSMIC.2007.4437216.
@article{osti_946671,
title = {Fast Neutron Sensitivity with HPGe},
author = {Seifert, Allen and Hensley, Walter K. and Siciliano, Edward R. and Pitts, W. K.},
abstractNote = {In addition to being excellent gamma-ray detectors, germanium detectors are also sensitive to fast neutrons. Incident neutrons undergo inelastic scattering {Ge(n,n')Ge*} off germanium nuclei and the resulting excited states emit gamma rays or conversion electrons. The response of a standard 140% high-purity germanium (HPGe) detector with a bismuth germanate (BGO) anti-coincidence shield was measured for several neutron sources to characterize the ability of the HPGe detector to detect fast neutrons. For a sensitivity calculation performed using the characteristic fast neutron response peak that occurs at 692 keV, the 140% germanium detector system exhibited a sensitivity of ~175 counts / kg of WGPumetal in 1000 seconds at a source-detector distance of 1 meter with 4 in. of lead shielding between source and detector. Theoretical work also indicates that it might be possible to use the shape of the fast-neutron inelastic scattering signatures (specifically, the end-point energy of the long high energy tail of the resulting asymmetric peak) to gain additional information about the energy distribution of the incident neutron spectrum. However, the experimentally observed end-point energies appear to be almost identical for each of the fast neutron sources counted. Detailed MCNP calculations show that the neutron energy distributions impingent on the detector for these sources are very similar in this experimental configuration, due to neutron scattering in a lead shield (placed between the neutron source and HPGe detector to reduce the gamma ray flux), the BGO anti-coincidence detector, and the concrete floor.},
doi = {10.1109/NSSMIC.2007.4437216},
url = {https://www.osti.gov/biblio/946671}, journal = {Nuclear Science Symposium Conference Record, 2007. NSS 07'. IEEE},
issn = {1095-7863},
number = ,
volume = 2,
place = {United States},
year = {2008},
month = {1}
}

Conference:
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