Nuclear Data Needs for Microcalorimetry and Non-destructive Assay

Cryogenic microcalorimeters are state-of-the-art radiation detectors using superconducting and quantum technologies. They can resolve complex X-ray and low-energy γray spectra with ultra-high energy resolution of an order of 10 eV at 100 keV, enabling highprecision non-destructive assay (NDA) analysis of nuclear materials containing uranium, plutonium and other actinides. With significant technical advancements in microcalorimetry technology, microcalorimeters are now deployable to end-users such as the International Atomic Energy Agency (IAEA) for improved NDA. However, the accuracy of microcalorimetry analysis can be limited by nuclear data. There are several cases that the current nuclear data obtained by conventional radiation detector technologies is not sufficient to support microcalorimetry analysis. To address the growing need for improved nuclear data in microcalorimetry, the U.S. Department of Energy Office of International Nuclear Safeguards hosted a workshop on Microcalorimetry and Nuclear Data (MiND) in June 2023. Microcalorimetry experts and users, and nuclear structure evaluators and managers, and program sponsors attended the workshop with the main objective of identifying a roadmap for priority nuclear data, stakeholders, partnerships, and opportunities. This paper summarizes the outcome of the MiND workshop, including the priority list of nuclear data for microcalorimetry and a multi-laboratory measurement campaign to improve such nuclear data.