New, room-temperature gamma-ray detector for improved assay of plutonium

Conference · Sat Nov 01 04:00:00 EST 1997

OSTI ID:549698

Russo, P A; Meier, A P; Rawool-Sullivan, M ^[1]

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1. and others

Gamma-ray spectroscopy for portable and unattended assay of nuclear materials requires rugged, reliable, room-temperature detectors that are stable in variable environments and detect gamma rays with good efficiency and energy resolution. For portable assays especially, compact detectors address needs for large numbers of measurements performed in rapid succession with heavy shielding and collimation by a user who must carry the spectroscopy equipment. Most measurements are made with compact NaI detectors. The assay of variable-burnup plutonium and other plutonium materials of variable isotopic composition challenges low-resolution gamma-ray spectroscopy in numerous safeguards applications including holdup measurements, safeguards inspections, monitoring, and safeguards close-out in decontamination and decommissioning. A new, commercial-prototype coplanar-grid CdZnTe detector has been evaluated using the assay of variable-burnup plutonium as a metric indicator to show the substantial benefit of its improved performance compared to results of the same measurements performed with the compact NaI detector. Detector performance, spectrum-quality, and assay results as well as gamma-ray spectra of reference sources are compared for the coplanar-grid CdZnTe and compact NaI detectors to illustrate the advantages of the new room-temperature gamma-ray detector. Isotope identification with the coplanar-grid CdZnTe detector is demonstrated. Preliminary calculations (Monte Carlo coupled to simulations of radiation transport and charge collection) of the spectral response of the detector to plutonium indicate promise for the use of the coplanar-grid CdZnTe detector for further improvements in the accuracy of assays and for analysis of gamma-ray isotopic distributions.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 549698
• Report Number(s): LA-UR--97-2782; CONF-970744--; ON: DE98001035
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
CADMIUM COMPOUNDS
DESIGN
GAMMA SPECTROMETERS
GAMMA SPECTROSCOPY
NUCLEAR MATERIALS MANAGEMENT
PERFORMANCE
PLUTONIUM
PORTABLE EQUIPMENT
QUALITY ASSURANCE
ZINC TELLURIDES