Ultra-high Resolution Alpha Particle Spectrometry with Transition-Edge Sensor Microcalorimeters

Alpha particle spectrometry is a powerful analytical tool for nuclear forensics and environmental monitoring. Microcalorimeter detectors have been shown to yield nearly an order of magnitude better energy resolution (1.06 keV FWHM at 5.3 MeV) than current state-of-the-art silicon detectors (8–10 keV FWHM at 5.3 MeV). This superior resolution allows isotopic analysis with a single non-consumptive measurement of samples that contain multiple radioisotopes with overlapping alpha energies. Measurement of such a sample with a silicon detector would require expensive and time-consuming radiochemical separations. We are developing two alpha spectrometer systems with superconducting transition-edge sensor microcalorimeters. The first system has eight independent detector channels that measure eight different alpha sources, and is optimized for detector development experiments. The second system incorporates a prototype cryogenic load lock that allows for rapid exchange of alpha samples. This paper will present results from these two systems.