SALER@FRIB: superconducting tunnel junctions for sub-keV precision nuclear physics experiments

Abstract

Precision beta decay is sensitive to TeV-scale physics via CKM unitarity (V_{ud}) and angular correlations (exotic scalar and tensor currents). However, beta spectroscopy is challenging. Nuclear recoil spectroscopy is sensitive to both, but typically inaccessible because of its low energy. New quantum sensors with great resolution and speed allow probing these energies at high rates. We have worked to characterize the electronics and predict the Standard Model spectrum for the Superconducting Array for Low Energy Radiation experiment, coming soon to the Facility for Rare Isotope Beams.