Skipper-CCD sensors for the Oscura experiment: requirements and preliminary tests
Brenda A. Cervantes-Vergara, Santiago Pérez, Juan Estrada, Ana Martina Botti, Claudio Chavez, Fernando Chierchie, N. Saffold, A. A. Aguilar-Arevalo, Fabricio Alcalde-Bessia, Nicolás Avalos, Oscar Baez, D. Baxter, X. Bertou, C. Bonifazi, Gustavo Cancelo, N. Castelló-Mor, Á. Chavarría, Juan Manuel De Egea, Juan Carlos D’Olivo, Cyrus E. Dreyer, A. Drlica-Wagner, Rouven Essig, Ezequiel Estrada, E. Etzion, Paul Grylls, Guillermo Fernandez-Moroni, Mariví Fernández-Serra, Santiago Ferreyra, S. T. Holland, Agustín Lantero Barreda, Andrew Lathrop, Ian T. Lawson, B. Loer, Steffon Luoma, Edgar Marrufo Villalpando, Mauricio Martinez Montero, Kellie McGuire, Jorge Molina, Sravan Munagavalasa, D. Norcini, A. Piers, Paolo Privitera, Darío Rodrigues, Richard Saldanha, Aman Singal, Radomir Šmída, Miguel Sofo-Haro, Diego Stalder, Leandro Stefanazzi, Javier Tiffenberg, Michelangelo Traina, Sho Uemura, Pedro Ventura, R. Vilar Cortabitarte, Rachana Yajur
Abstract
Abstract Oscura is a proposed multi-kg skipper-CCD experiment designed for a dark matter (DM) direct detection search that will reach unprecedented sensitivity to sub-GeV DM-electron interactions with its 10 kg detector array. Oscura is planning to operate at SNOLAB with 2070 m overburden, and aims to reach a background goal of less than one event in each electron bin in the 2–10 electron ionization-signal region for the full 30 kg-year exposure, with a radiation background rate of 0.01 dru.[1 dru (differential rate unit) corresponds to 1 event/kg/day/keV.] In order to achieve this goal, Oscura must address each potential source of background events, including instrumental backgrounds. In this work, we discuss the main instrumental background sources and the strategy to control them, establishing a set of constraints on the sensors' performance parameters. We present results from the tests of the first fabricated Oscura prototype sensors, evaluate their performance in the context of the established constraints and estimate the Oscura instrumental background based on these results.