The Selena Neutrino Experiment

We present the scientific case and R&D status of The Selena Neutrino Experiment. The Selena Neutron Experiment will consist of 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. The high spatial resolution in a solid-state target provides unparalleled rejection of backgrounds from natural radioactivity. We explore the scientific reach of a detector with a 10-ton target of Se-82 in the search for neutrinoless ββ decay, solar neutrino spectroscopy and neutrino oscillations. 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.