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Title: Measurement of Radioactive Contamination in the High-Resistivity Silicon CCDs of the DAMIC Experiment

Journal Article · · Journal of Instrumentation
 [1]
  1. Universidad Nacional Autonoma de Mexico (Mexico). et al.

We present measurements of radioactive contamination in the high-resistivity silicon charge-coupled devices (CCDs) used by the DAMIC experiment to search for dark matter particles. Novel analysis methods, which exploit the unique spatial resolution of CCDs, were developed to identify α and β particles. Uranium and thorium contamination in the CCD bulk was measured through α spectroscopy, with an upper limit on the 238U (232Th) decay rate of 5 (15) kg-1 d-1 at 95% CL. We also searched for pairs of spatially correlated electron tracks separated in time by up to tens of days, as expected from 32Si –32P or 210Pb –210Bi sequences of b decays. The decay rate of 32Si was found to be 80+110-65 (95% CI). An upper limit of ~35 kg -1 d-1 (95% CL) on the 210Pb decay rate was obtained independently by α spectroscopy and the β decay sequence search. Furthermore, these levels of radioactive contamination are sufficiently low for the successful operation of CCDs in the forthcoming 100 g DAMIC detector.

Research Organization:
Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP)
Contributing Organization:
DAMIC Collaboration
Grant/Contract Number:
AC02-07CH11359
OSTI ID:
1223218
Report Number(s):
FERMILAB-PUB-15-315-A-CD-E; arXiv eprint number arXiv:1506.02562
Journal Information:
Journal of Instrumentation, Vol. 10, Issue P08014; ISSN 1748-0221
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 28 works
Citation information provided by
Web of Science

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Cited By (9)

The SNOLAB Science Program journal May 2016
The CONNIE experiment journal October 2016
DarkSide-20k: A 20 tonne two-phase LAr TPC for direct dark matter detection at LNGS journal March 2018
Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB text January 2016
Cosmogenic activation of materials conference January 2005
First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter with DAMIC at SNOLAB text January 2017
Cosmogenic activation of materials
  • Cebrián, S.
  • LOW RADIOACTIVITY TECHNIQUES 2013 (LRT 2013): Proceedings of the IV International Workshop in Low Radioactivity Techniques, AIP Conference Proceedings https://doi.org/10.1063/1.4818094
conference January 2013
Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB text January 2016
DarkSide-20k: A 20 Tonne Two-Phase LAr TPC for Direct Dark Matter Detection at LNGS text January 2017