Skipper-CCD Sensors for the Oscura Experiment: Requirements and Preliminary Tests

Oscura is a proposed multi-kg skipper-CCD experiment designed for a darkmatter (DM) direct detection search that will reach unprecedented sensitivityto sub-GeV DM-electron interactions with its 10 kg detector array. Oscura isplanning to operate at SNOLAB with 2070 m overburden, and aims to reach abackground goal of less than one event in each electron bin in the 2-10electron ionization-signal region for the full 30 kg-year exposure, with aradiation background rate of 0.01 dru. In order to achieve this goal, Oscuramust address each potential source of background events, including instrumentalbackgrounds. In this work, we discuss the main instrumental background sourcesand the strategy to control them, establishing a set of constraints on thesensors' performance parameters. We present results from the tests of the firstfabricated Oscura prototype sensors, evaluate their performance in the contextof the established constraints and estimate the Oscura instrumental backgroundbased on these results.