학술논문
Characterization of the background spectrum in DAMIC at SNOLAB
Document Type
Working Paper
Author
Aguilar-Arevalo, A.; Amidei, D.; Arnquist, I.; Baxter, D.; Cancelo, G.; Vergara, B. A. Cervantes; Chavarria, A. E.; Corso, N.; Darragh-Ford, E.; Di Vacri, M. L.; D'Olivo, J. C.; Estrada, J.; Favela-Perez, F.; Gaïor, R.; Guardincerri, Y.; Hossbach, T. W.; Kilminster, B.; Lawson, I.; Lee, S. J.; Letessier-Selvon, A.; Matalon, A.; Mitra, P.; Piers, A.; Privitera, P.; Ramanathan, K.; Da Rocha, J.; Settimo, M.; Smida, R.; Thomas, R.; Tiffenberg, J.; Machado, D. Torres; Traina, M.; Vilar, R.; Virto, A. L.
Source
Phys. Rev. D 105, 062003 (2022)
Subject
Language
Abstract
We construct the first comprehensive radioactive background model for a dark matter search with charge-coupled devices (CCDs). We leverage the well-characterized depth and energy resolution of the DAMIC at SNOLAB detector and a detailed GEANT4-based particle-transport simulation to model both bulk and surface backgrounds from natural radioactivity down to 50 eV$_{\text{ee}}$. We fit to the energy and depth distributions of the observed ionization events to differentiate and constrain possible background sources, for example, bulk $^{3}$H from silicon cosmogenic activation and surface $^{210}$Pb from radon plate-out. We observe the bulk background rate of the DAMIC at SNOLAB CCDs to be as low as $3.1 \pm 0.6$ counts kg$^{-1}$ day$^{-1}$ keV$_{\text{ee}}^{-1}$, making it the most sensitive silicon dark matter detector. Finally, we discuss the properties of a statistically significant excess of events over the background model with energies below 200 eV$_{\text{ee}}$.
Comment: 27 pages, 19 figures
Comment: 27 pages, 19 figures