The Selena Neutrino Experiment

Abstract

Imaging sensors made from an ionization target layer of amorphous selenium (aSe) coupled to a silicon complementary metal-oxide-semiconductor (CMOS) active pixel array for charge readout are a promising technology for neutrino physics. The high spatial resolution in a solid-state target provides unparalleled rejection of backgrounds from natural radioactivity in the search for neutrinoless ββ decay and for solar neutrino spectroscopy with 82Se. We present results on the ionization response of aSe measured from the photoabsorption of 122 keV γ rays in a single-pixel device. We report on the progress in the fabrication and testing of the first prototype imaging sensors based on the Topmetal II − pixelated CMOS charge readout chip. We explore the scientific reach of a large neutrino detector with the proposed technology based on our experimental understanding of the sensor performance.

High-efficiency recovery of 82Se from enriched Zn82Se scintillating bolometer crystals

“…In conclusion, the highly effective extraction technique (with the yield no less than 86.4%, that potentially can be higher than 94.7%) presented here allows for the recovery of selenium of different levels of 82 Se enrichment (84% and 95.5%) and various chemical-and radio-purity levels. This recovered selenium could be used to produce more Zn 82 Se scintillating crystals in case of an extension of the CUPID-0 research program or other low-background experiments (such as SELENA [42]) focused on studies of rare nuclear processes and seeking enriched selenium isotopes.…”