2021/03/29 by K. Koehler, Koehler, Katrina E., Michael Duncan Yoho +36
Physics and Astronomy · #FOS: Physical sciences #Neutrino Physics Research #Nuclear Experiment (nucl-ex) #Particle physics theoretical and experimental studies #Superconducting and THz Device Technology
paper · pdf · doi:10.48550/arxiv.2103.15893
openalex publication_date 2021/03/29 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
With the high resolution of microcalorimeter detectors, previously\nunresolvable gamma-ray lines are now clearly resolvable. A careful measurement\nof Am-241 decay with a large array of gamma-ray microcalorimeters has revealed\nnever before seen or predicted gamma lines at 207.72 +/- 0.02 keV and 208.21\n+/- 0.01 keV. These results were made possible by new microwave-multiplexing\nreadout to increase the array size and improved analysis algorithms to\neliminate spectral artifacts. We suggest nuclear levels from which these\ngamma-rays might originate and calculate branching ratios for these transitions\nfrom measurements of both mixed Pu-Am standards and a pure Am-241 source. These\nresults have implications for nuclear material safeguards and accounting,\nparticularly for microcalorimeter gamma spectrometers, which are now being\nadopted in nuclear safeguards analytical laboratories.\n