FRAM v5.2 estimation of plutonium and uranium isotopics using digitized 3-D position-sensitive CdZnTe detectors

Gamma-ray spectroscopy is an important tool used in international safeguards to measure plutonium and uranium isotopics. Recently developed, digital, 3-D position-sensitive CdZnTe gamma-ray spectrometers are promising for safeguards, offering improved performance over commonly available CdZnTe systems, with energy resolutions approaching that of high-purity germanium. CdZnTe gamma-ray spectra from plutonium and uranium samples were processed using the commercially available software FRAM v5.2, a tool that estimates plutonium and uranium isotopics from high-purity germanium spectra, across a wide range of materials. Using digital CdZnTe systems Pu-239/Pu-240 isotopic composition and effective Pu-240 percentage are evaluated to within less than 3 sigma statistical measurement uncertainty across reactor to weapons-grade samples, while low and highly-enriched uranium are easily distinguished.