University of Colorado, Boulder (CU-Boulder)

The University of Colorado, Boulder (CU-Boulder), will advance high-resolution gamma-ray spectroscopy using cryogenic microcalorimeter arrays, which are an emerging tool for improved nuclear material accountancy. Microcalorimeter spectrometers measure gamma-ray energy much more precisely than other gamma-ray detectors, allowing them to resolve closely spaced gamma-ray lines such as those produced by plutonium isotopes near 100 keV, and detect lines that appear only weakly above background. Microcalorimeters are currently capable of reaching the CURIE program’s 1% uncertainty target but fall far short of its speed goal. CU-Boulder will produce individual microcalorimeter pixels that can achieve 200 counts per second count rates (20x faster than current devices), which will allow a system with 4,000 such detectors to make the required 1% measurement of plutonium isotopic content in 2 minutes. This capability can determine uranium (U) enrichment in high-assay low-enriched U, fissile material content throughout reprocessing and waste streams, high-accuracy plutonium (Pu) isotopic assays, and potentially key U/Pu isotope ratios in uranium/transuranic products.

By enabling the secure and economical recycling of the nation’s inventory of LWR UNF, CURIE will have the following impacts: