Delayed gamma-ray spectroscopy with lanthanum bromide detector for non-destructive assay of nuclear material

Journal Article · Mon Oct 09 00:00:00 EDT 2017 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI:https://doi.org/10.1016/j.nima.2017.09.054· OSTI ID:1402648

Favalli, Andrea ^[1]; Iliev, Metodi ^[1]; Ianakiev, Kiril ^[1]; Hunt, Alan W. ^[2]; Ludewigt, Bernhard ^[3]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Johns Hopkins Univ. Applied Physics Lab., Laurel, MD (United States)
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

High-energy delayed γ-ray spectroscopy is a potential technique for directly assaying spent fuel assemblies and achieving the safeguards goal of quantifying nuclear material inventories for spent fuel handling, interim storage, reprocessing facilities, repository sites, and final disposal. Requirements for the γ-ray detection system, up to ~6 MeV, can be summarized as follows: high efficiency at high γ-ray energies, high energy resolution, good linearity between γ-ray energy and output signal amplitude, ability to operate at very high count rates, and ease of use in industrial environments such as nuclear facilities. High Purity Germanium Detectors (HPGe) are the state of the art and provide excellent energy resolution but are limited in their count rate capability. Lanthanum Bromide (LaBr₃) scintillation detectors offer significantly higher count rate capabilities at lower energy resolution. Thus, LaBr₃ detectors may be an effective alternative for nuclear spent-fuel applications, where count-rate capability is a requirement. This paper documents the measured performance of a 2” (length) × 2” (diameter) of LaBr3 scintillation detector system, coupled to a negatively biased PMT and a tapered active high voltage divider, with count-rates up to ~3 Mcps. An experimental methodology was developed that uses the average current from the PMT’s anode and a dual source method to characterize the detector system at specific very high count rate values. Delayed γ-ray spectra were acquired with the LaBr₃ detector system at the Idaho Accelerator Center, Idaho State University, where samples of ~3g of ²³⁵U were irradiated with moderated neutrons from a photo-neutron source. Results of the spectroscopy characterization and analysis of the delayed γ-ray spectra acquired indicate the possible use of LaBr3 scintillation detectors when high count rate capability may outweigh the lower energy resolution.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1402648
• Alternate ID(s): OSTI ID: 1661717
• Report Number(s): LA-UR-17-26601; TRN: US1703244
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 877, Issue C; ISSN 0168-9002
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
delayed gamma-ray
ultra-high count rate
gamma spectroscopy
LaBr3 detector
nondestructive assay of spent nuclear fuel.