Gamma-Ray Measurements of Uranium Items Inside an AWCC

Researchers at Los Alamos National Laboratory are building a new Attribute Measurement System (AMS) to measure uranium in a sealed container behind an information barrier. Our AMS uses (a) an active well coincidence counter that measures the mass of U-235 and (b) a high-purity germanium (HPGe) detector system that collects gamma-ray spectra. The isotopic analysis code FRAM analyzes these spectra to determine the U-235’s enrichment. To conduct such measurements, the uranium in a sealed container is placed inside the neutron counter. Gamma rays must pass through more than 20 cm of polyethylene to reach the HPGe detector. Such measurement conditions introduce several challenges to this analysis.