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Title: Scintillation light from cosmic-ray muons in liquid argon

This paper reports the results of an experiment to directly measure the time-resolved scintillation signal from the passage of cosmic-ray muons through liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches. The experiment was carried out at the TallBo dewar facility at Fermilab using prototype light guide detectors and electronics developed for the Deep Underground Neutrino Experiment. Two models are presented for the time structure of the scintillation light, a phenomenological model and a physically-motivated model. Both models find tT = 1:52 ms for the decay time constant of the Ar 2 triplet state. These models also show that the identification of the “early” light fraction in the phenomenological model, FE 25% of the signal, with the total light from singlet decays is an underestimate. The total fraction of singlet light is FS 36%, where the increase over FE is from singlet light emitted by the wavelength shifter through processes with long decay constants. The models were further used to compute the experimental particle identification parameter Fprompt, the fraction of light coming in a short time window after the trigger compared with the light in the totalmore » recorded waveform. The models reproduce quite well the typical experimental value 0.3 found by dark matter and double b-decay experiments, which suggests this parameter provides a robust metric for discriminating electrons and muons from more heavily ionizing particles.« less
Authors:
 [1] ;  [2] ;  [1]
  1. Indiana Univ., Bloomington, IN (United States). Physics Dept.
  2. Indiana Univ., Bloomington, IN (United States). Astronomy Dept.
Publication Date:
Report Number(s):
FERMILAB-PUB-14-413-E; FERMILAB-PUB-15-488-ND-PPD; arXiv:1408.1763
Journal ID: ISSN 1748-0221; 1310270
Grant/Contract Number:
AC02-07CH11359
Type:
Accepted Manuscript
Journal Name:
Journal of Instrumentation
Additional Journal Information:
Journal Volume: 11; Journal Issue: 05; Journal ID: ISSN 1748-0221
Publisher:
Institute of Physics (IOP)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
OSTI Identifier:
1253184

Whittington, Denver Wade, Mufson, S., and Howard, B.. Scintillation light from cosmic-ray muons in liquid argon. United States: N. p., Web. doi:10.1088/1748-0221/11/05/P05016.
Whittington, Denver Wade, Mufson, S., & Howard, B.. Scintillation light from cosmic-ray muons in liquid argon. United States. doi:10.1088/1748-0221/11/05/P05016.
Whittington, Denver Wade, Mufson, S., and Howard, B.. 2016. "Scintillation light from cosmic-ray muons in liquid argon". United States. doi:10.1088/1748-0221/11/05/P05016. https://www.osti.gov/servlets/purl/1253184.
@article{osti_1253184,
title = {Scintillation light from cosmic-ray muons in liquid argon},
author = {Whittington, Denver Wade and Mufson, S. and Howard, B.},
abstractNote = {This paper reports the results of an experiment to directly measure the time-resolved scintillation signal from the passage of cosmic-ray muons through liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches. The experiment was carried out at the TallBo dewar facility at Fermilab using prototype light guide detectors and electronics developed for the Deep Underground Neutrino Experiment. Two models are presented for the time structure of the scintillation light, a phenomenological model and a physically-motivated model. Both models find tT = 1:52 ms for the decay time constant of the Ar 2 triplet state. These models also show that the identification of the “early” light fraction in the phenomenological model, FE 25% of the signal, with the total light from singlet decays is an underestimate. The total fraction of singlet light is FS 36%, where the increase over FE is from singlet light emitted by the wavelength shifter through processes with long decay constants. The models were further used to compute the experimental particle identification parameter Fprompt, the fraction of light coming in a short time window after the trigger compared with the light in the total recorded waveform. The models reproduce quite well the typical experimental value 0.3 found by dark matter and double b-decay experiments, which suggests this parameter provides a robust metric for discriminating electrons and muons from more heavily ionizing particles.},
doi = {10.1088/1748-0221/11/05/P05016},
journal = {Journal of Instrumentation},
number = 05,
volume = 11,
place = {United States},
year = {2016},
month = {5}
}