TY - JOUR
T1 - Measurement of the bulk radioactive contamination of detector-grade silicon with DAMIC at SNOLAB
AU - Damic Collaboration, The
AU - Aguilar-Arevalo, A.
AU - Amidei, D.
AU - Baxter, D.
AU - Cancelo, G.
AU - Cervantes Vergara, B. A.
AU - Chavarria, A. E.
AU - Darragh-Ford, E.
AU - D'Olivo, J. C.
AU - Estrada, J.
AU - Favela-Perez, F.
AU - Gaïor, R.
AU - Guardincerri, Y.
AU - Hossbach, T. W.
AU - Kilminster, B.
AU - Lawson, I.
AU - Lee, S. J.
AU - Letessier-Selvon, A.
AU - Matalon, A.
AU - Mitra, P.
AU - Piers, A.
AU - Privitera, P.
AU - Ramanathan, K.
AU - Da Rocha, J.
AU - Sarkis, Y.
AU - Settimo, M.
AU - Smida, R.
AU - Thomas, R.
AU - Tiffenberg, J.
AU - Traina, M.
AU - Vilar, R.
AU - Virto, A. L.
N1 - Publisher Copyright:
© 2021 IOP Publishing Ltd and Sissa Medialab.
PY - 2021/6
Y1 - 2021/6
N2 - We present measurements of bulk radiocontaminants in the high-resistivity silicon CCDs from the DAMIC experiment at SNOLAB. We utilize the exquisite spatial resolution of CCDs to discriminate between α and β decays, and to search with high efficiency for the spatially-correlated decays of various radioisotope sequences. Using spatially-correlated β decays, we measure a bulk radioactive contamination of 32Si in the CCDs of 140 ± 30 μBq/kg, and place an upper limit on bulk 210Pb of < 160 μBq/kg. Using similar analyses of spatially-correlated α and β decays, we set upper limits of < 11 μBq/kg (0.9 ppt) on 238U and < 7.3 μBq/kg (1.8 ppt) on 232Th in the bulk silicon. The ability of DAMIC CCDs to identify and reject spatially-coincident backgrounds, particularly from 32Si, has significant implications for the next generation of silicon-based dark matter experiments, where β's from 32Si decay will likely be a dominant background.
AB - We present measurements of bulk radiocontaminants in the high-resistivity silicon CCDs from the DAMIC experiment at SNOLAB. We utilize the exquisite spatial resolution of CCDs to discriminate between α and β decays, and to search with high efficiency for the spatially-correlated decays of various radioisotope sequences. Using spatially-correlated β decays, we measure a bulk radioactive contamination of 32Si in the CCDs of 140 ± 30 μBq/kg, and place an upper limit on bulk 210Pb of < 160 μBq/kg. Using similar analyses of spatially-correlated α and β decays, we set upper limits of < 11 μBq/kg (0.9 ppt) on 238U and < 7.3 μBq/kg (1.8 ppt) on 232Th in the bulk silicon. The ability of DAMIC CCDs to identify and reject spatially-coincident backgrounds, particularly from 32Si, has significant implications for the next generation of silicon-based dark matter experiments, where β's from 32Si decay will likely be a dominant background.
KW - Dark Matter detectors (WIMPs, axions, etc.)
KW - Particle identification methods
KW - Search for radioactive and fissile materials
KW - Solid state detectors
UR - https://www.scopus.com/pages/publications/85109124539
U2 - 10.1088/1748-0221/16/06/P06019
DO - 10.1088/1748-0221/16/06/P06019
M3 - Article
AN - SCOPUS:85109124539
SN - 1748-0221
VL - 16
JO - Journal of Instrumentation
JF - Journal of Instrumentation
IS - 6
M1 - P06019
ER -