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Proceedings Paper

Maximum likelihood source localization using elpasolite crystals as a dual gamma neutron directional detector
Author(s): Paul P. Guss; Thomas G. Stampahar; Sanjoy Mukhopadhyay; Alexander Barzilov; Amber Guckes
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Paper Abstract

The problem of accurately detecting extremely low levels of nuclear radiation is rapidly increasing in importance in nuclear counter-proliferation, verification, and environmental and waste management. Because the 239Pu gamma signature may be weak, for instance, even when compared to the natural terrestrial background, coincidence counting with the 239Pu neutron signature may improve overall 239Pu detection sensitivity. However, systems with sufficient multiple-particle detectors require demonstration that the increased sensitivity be sufficiently high to overcome added cost and weight. We report the results of measurements and calculations to determine sensitivity that can be gained in detecting low levels of nuclear radiation from use of a relatively new detector technology based on elpasolite crystals. We have performed investigations exploring cerium (Ce3+)-doped elpasolites Cs2LiYCl6:Ce3+0.5% (CLYC) and Cs2LiLa(Br6)90%(Cl6)10%:Ce3+0.5% (CLLBC:Ce). These materials can provide energy resolution (r(E) = 2.35σ(E)/E) as good as 2.9% at 662 keV (FWHM). The crystals show an excellent neutron and gamma radiation response. The goals of the investigation were to set up the neutron/gamma pulse shape discrimination electronics for elpasolite detectors; perform limited static source benchmarking, testing, and evaluation to validate system performance; and explore application of a maximum likelihood algorithm for source location. Data were measured and processed through a maximum likelihood estimation algorithm, providing a direction to the radioactive source for each individual position. The estimated directions were good representations for the actual directions to the radioactive source. This paper summarizes the maximum likelihood results for our elpasolite system.

Paper Details

Date Published: 27 August 2015
PDF: 17 pages
Proc. SPIE 9595, Radiation Detectors: Systems and Applications XVI, 959502 (27 August 2015); doi: 10.1117/12.2186179
Show Author Affiliations
Paul P. Guss, National Security Technologies, LLC (United States)
Thomas G. Stampahar, National Security Technologies, LLC (United States)
Sanjoy Mukhopadhyay, National Security Technologies, LLC (United States)
Alexander Barzilov, Univ. of Nevada, Las Vegas (United States)
Amber Guckes, Univ. of Nevada, Las Vegas (United States)

Published in SPIE Proceedings Vol. 9595:
Radiation Detectors: Systems and Applications XVI
Gary P. Grim; H. Bradford Barber, Editor(s)

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