Abstract
Many current and future dark matter and neutrino detectors are designed to measure scintillation light with a large array of photomultiplier tubes (PMTs). The energy resolution and particle identification capabilities of these detectors depend in part on the ability to accurately identify individual photoelectrons in PMT waveforms despite large variability in pulse amplitudes and pulse pileup. We describe a Bayesian technique that can identify the times of individual photoelectrons in a sampled PMT waveform without deconvolution, even when pileup is present. To demonstrate the technique, we apply it to the general problem of particle identification in single-phase liquid argon dark matter detectors. Using the output of the Bayesian photoelectron counting algorithm described in this paper, we construct several test statistics for rejection of backgrounds for dark matter searches in argon. Compared to simpler methods based on either observed charge or peak finding, the photoelectron counting technique improves both energy resolution and particle identification of low energy events in calibration data from the DEAP-1 detector and simulation of the larger MiniCLEAN dark matter detector.
Original language | English |
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Pages (from-to) | 40-54 |
Number of pages | 15 |
Journal | Astroparticle Physics |
Volume | 65 |
DOIs | |
State | Published - May 2015 |
Externally published | Yes |
Funding
Support for DEAP-1 has been provided by the Canadian Foundation for Innovation and the Natural Sciences and Engineering Research Council . The High Performance Computing Virtual Laboratory (HPCVL) has provided us with CPU time, data storage, and support. We would also like to thank the SNOLAB staff for on-site support. The work of our co-op and summer students, including Christopher Stanford who operated DEAP-1 during the data-taking in this paper, is gratefully acknowledged. This work has in part been supported by the United States Department of Energy , Office of High Energy Physics .
Funders | Funder number |
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U.S. Department of Energy | |
High Energy Physics | |
Natural Sciences and Engineering Research Council of Canada | |
Canada Foundation for Innovation | |
Science and Technology Facilities Council | ST/K502261/1, ST/K001264/1, ST/K002570/1 |
Keywords
- Dark matter
- Liquid argon
- Neutrino
- Pulse-shape discrimination