Measurement of the scintillation time spectra and pulse-shape discrimination of low-energy β and nuclear recoils in liquid argon with DEAP-1
The DEAP-1 low-background liquid argon detector has been used to measure scintillation pulse shapes of beta decays and nuclear recoil events and to demonstrate the feasibility of pulse-shape discrimination down to an electron-equivalent energy of 20 keVee. The relative intensities of singlet/triplet states in liquid argon have been measured as a function of energy between 15 and 500 keVee for both beta and nuclear recoils. Using a triple-coincidence tag we find the fraction of beta events that are misidentified as nuclear recoils to be less than 6 x 10-8 between 43-86 keVee and that the discrimination parameter agrees with a simple analytic model. The discrimination measurement is currently limited by nuclear recoils induced by cosmic-ray generated neutrons, and is expected to improve by operating the detector underground at SNOLAB. The analytic model predicts a beta misidentification fraction of 10-10 for an electron-equivalent energy threshold of 20 keVee. This reduction allows for a sensitive search for spin-independent scattering of WIMPs from 1000 kg of liquid argon with a WIMP-nucleon cross-section sensitivity of 10-46 cm2.
- Research Organization:
- Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP); National Science and Engineering Research Council of Canada (NSERC); Canada Foundation for Innovation (CFI); Ontario Ministry of Research and Innovation (MRI); David and Lucille Packard Foundation
- Contributing Organization:
- DEAP Collaboration
- Grant/Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1368371
- Report Number(s):
- FERMILAB-PUB-16-697-AE; arXiv:0904.2930; 818299
- Journal Information:
- Astroparticle Physics, Vol. 85, Issue C; ISSN 0927-6505
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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