Wd. Ruhter et R. Gunnink, APPLICATION OF CADMIUM ZINC TELLURIDE DETECTORS IN U-235 ENRICHMENT MEASUREMENTS, Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment, 353(1-3), 1994, pp. 716-718
High-resolution, gamma- and X-ray spectrometry are used routinely in n
uclear safeguards verification measurements of plutonium and uranium i
n the field. These measurements are mostly performed with high-purity
germanium (HPGe) detectors, that require cooling to liquid-nitrogen te
mperatures, thus limiting their utility in field and unattended safegu
ards measurement applications. NaI scintillation detectors do not requ
ire cooling, but their moderate energy resolution (10% at 122 keV) is
insufficient in most cases for reliable verification measurements. Sem
iconductor detectors that operate at room temperature, such as cadmium
-zinc-telluride (CdZnTe) detectors, with energy resolution performance
reaching 2.0% at 122 keV may complement HPGe detectors for certain sa
feguards verification applications. We used a 5 X 5 X 5 mm CdZnTe dete
ctor to measure U-235 enrichments ranging from 3% to 75%, We use a spe
ctrum analysis technique that fits U-235, U-238, and U K X-ray respons
e profiles to data in the 89- to 100-keV region of a gamma-ray spectru
m. From the relative magnitudes of the U-235 and U-238 profiles we det
ermine the U-235 enrichment with an accuracy of about 10% with CdZnTe
detectors.