Measurement of the bulk radioactive contamination of detector-grade silicon with DAMIC at SNOLAB
Measurement of the bulk radioactive contamination of detector-grade silicon with DAMIC at SNOLAB
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DOI：
10.1088/1748-0221/16/06/p06019
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发表时间：
2020-11
影响因子：
1.3
通讯作者：
A. Aguilar-Arevalo;D. Amidei;D. Baxter;G. Cancelo;B. C. Cervantes Vergara;A. Chavarria;Elise Darragh-Ford;J. D'Olivo;J. Estrada;F. Favela-Pérez;R. Gaïor;Y. Guardincerri;T. Hossbach;B. Kilminster;I. Lawson;S.J. Lee;A. Letessier-Selvon;A. Matalon;P. Mitra;A. Piers;P. Privitera;K. Ramanathan;J. Da Rocha;Youssef Sarkis Mobarak;M. Settimo;R. Smida;R. Thomas;J. Tiffenberg;M. Traina;R. Vilar;A. L. Virto
中科院分区：
文献类型：
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作者：
A. Aguilar-Arevalo;D. Amidei;D. Baxter;G. Cancelo;B. C. Cervantes Vergara;A. Chavarria;Elise Darragh-Ford;J. D'Olivo;J. Estrada;F. Favela-Pérez;R. Gaïor;Y. Guardincerri;T. Hossbach;B. Kilminster;I. Lawson;S.J. Lee;A. Letessier-Selvon;A. Matalon;P. Mitra;A. Piers;P. Privitera;K. Ramanathan;J. Da Rocha;Youssef Sarkis Mobarak;M. Settimo;R. Smida;R. Thomas;J. Tiffenberg;M. Traina;R. Vilar;A. L. Virto
我们目前的测量散装放射性污染物的高电阻率硅CCD的DAMIC实验在SNOLAB。我们利用CCD精细的空间分辨率来区分α和β衰变，并高效地搜索各种放射性同位素序列的空间相关衰变。使用空间相关β衰变，我们测量了CCD中32 Si的140 ± 30 μBq/kg的体放射性污染，并将体210 Pb的上限设定为< 160 μBq/kg。使用空间相关α和β衰变的类似分析，我们将体硅中238 U的上限设定为< 11 μBq/kg（0.9 ppt），232 Th的上限设定为< 7.3 μBq/kg（1.8 ppt）。DAMIC CCD识别和拒绝空间一致背景的能力，特别是来自32 Si的，对下一代硅基暗物质实验具有重要意义，其中来自32 Si衰变的β可能是主要背景。
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.