Development of a hybrid amorphous Selenium/CMOS detector for the Selena Neutrino Experiment

The Selena Neutrino Experiment couples a
⁸²
Se enriched amorphous selenium (aSe) ionization target to a complimentary metal-oxide semiconductor (CMOS) active pixel array as an imaging detector for next generation neutrino physics. The high Q value of
⁸²
Se and the excellent event classification allows for a search for neutrinoless double beta decay free from environmental backgrounds. Furthermore, we can take advantage of the spatiotemporal resolution to perform high efficiency electron neutrino spectroscopy for solar neutrino studies and sterile neutrino searches. The Selena experiment will operate with a 10-ton target for a 100-ton year exposure. We are currently characterizing our first prototypes of the Selena detectors, which consist of 500um of aSe deposited on the Topmetal-II− CMOS pixel charge sensor. We present R&D results from our studies and show the induced beta and gamma tracks within our detector, as well as a noise performance of 23 electrons. We also present status on the development of the next version of the Selena detectors, which were fabricated using the open-source Skywater 130nm process..