Progress on Development of the Decay Energy Spectrometer for Nuclear Material Analysis at IAEA NML

The IAEA Nuclear Material Laboratory (NML) currently employs Isotope Dilution Thermal Ionization Mass Spectrometry (ID-TIMS) for the precise analysis of nuclear material samples. While this methodology is highly precise, its labor-intensive and time-consuming nature poses challenges, especially with the increasing number of samples over the years. Decay Energy Spectrometry (DES), which utilizes cryogenic microcalorimeters with ultra-high energy resolution to measure the decay energies of embedded radionuclides, emerges as a promising complementary methodology for nuclear material analysis. DES is a radiometric technique that is independent of mass spectrometry and provides sub-percent precision within a few days of the full measurement cycle. A DES instrument with user-friendly features has been developed through a collaborative effort between Lawrence Livermore and Los Alamos National Laboratories (LLNL and LANL) for routine analysis of nuclear material samples at IAEA NML. This instrument incorporates two independent and complementary microcalorimeter technologies to analyze a wide variety of sample types and to minimize potential biases in analyses. The presentation will introduce various features of the DES instrument, including its composition, form factor, performance, and software for data acquisition and spectral analysis.