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Title: Cosmogenic production of 39Ar and 37Ar in argon

Abstract

We have experimentally determined the production rate of 39Ar and 37Ar from cosmic ray neutron interactions in argon at sea level. Understanding these production rates is important for argon-based dark matter experiments that plan to utilize argon extracted from deep underground because it is imperative to know what the ingrowth of 39Ar will be during the production, transport, and storage of the underground argon. These measurements also allow for the prediction of 39Ar and 37Ar concentrations in the atmosphere which can be used to determine the presence of other sources of these isotopes. Through controlled irradiation with a neutron beam that mimics the cosmic ray neutron spectrum, followed by direct counting of 39Ar and 37Ar decays with sensitive ultra-low background proportional counters, we determined that the production rate from cosmic ray neutrons at sea-level is expected to be (759 ± 128) atoms/kg/day for 39Ar, and (51.0 ± 7.4) atoms/kg/day for 37Ar. We also performed a survey of the alternate production mechanisms based on the state-of-knowledge of the associated cross-sections to obtain a total sea-level cosmic ray production rate of (1048 ± 133) atoms/kg/day for 39Ar, (56.7 ± 7.5) atoms/kg/day for 37Ar in underground argon, and (92 ± 13) atoms/kg/day formore » 37Ar in atmospheric argon.« less

Authors:
ORCiD logo [1];  [1];  [1]; ORCiD logo [1];  [2];  [1]; ORCiD logo [1];  [1];  [1]
  1. BATTELLE (PACIFIC NW LAB)
  2. Los Alamos National Laboratory, Los Alamos, NM
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1568065
Report Number(s):
PNNL-SA-141556
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 100; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
argon, cosmogenic, activation, 39Ar, 37Ar

Citation Formats

Saldanha, Richard N., Back, Henning O., Tsang, Hei Man, Alexander, Thomas R., Elliott, Steven R., Ferrara, Seth A., Mace, Emily K., Overman, Cory T., and Zalavadia, Mital A. Cosmogenic production of 39Ar and 37Ar in argon. United States: N. p., 2019. Web. doi:10.1103/PhysRevC.100.024608.
Saldanha, Richard N., Back, Henning O., Tsang, Hei Man, Alexander, Thomas R., Elliott, Steven R., Ferrara, Seth A., Mace, Emily K., Overman, Cory T., & Zalavadia, Mital A. Cosmogenic production of 39Ar and 37Ar in argon. United States. doi:10.1103/PhysRevC.100.024608.
Saldanha, Richard N., Back, Henning O., Tsang, Hei Man, Alexander, Thomas R., Elliott, Steven R., Ferrara, Seth A., Mace, Emily K., Overman, Cory T., and Zalavadia, Mital A. Mon . "Cosmogenic production of 39Ar and 37Ar in argon". United States. doi:10.1103/PhysRevC.100.024608.
@article{osti_1568065,
title = {Cosmogenic production of 39Ar and 37Ar in argon},
author = {Saldanha, Richard N. and Back, Henning O. and Tsang, Hei Man and Alexander, Thomas R. and Elliott, Steven R. and Ferrara, Seth A. and Mace, Emily K. and Overman, Cory T. and Zalavadia, Mital A.},
abstractNote = {We have experimentally determined the production rate of 39Ar and 37Ar from cosmic ray neutron interactions in argon at sea level. Understanding these production rates is important for argon-based dark matter experiments that plan to utilize argon extracted from deep underground because it is imperative to know what the ingrowth of 39Ar will be during the production, transport, and storage of the underground argon. These measurements also allow for the prediction of 39Ar and 37Ar concentrations in the atmosphere which can be used to determine the presence of other sources of these isotopes. Through controlled irradiation with a neutron beam that mimics the cosmic ray neutron spectrum, followed by direct counting of 39Ar and 37Ar decays with sensitive ultra-low background proportional counters, we determined that the production rate from cosmic ray neutrons at sea-level is expected to be (759 ± 128) atoms/kg/day for 39Ar, and (51.0 ± 7.4) atoms/kg/day for 37Ar. We also performed a survey of the alternate production mechanisms based on the state-of-knowledge of the associated cross-sections to obtain a total sea-level cosmic ray production rate of (1048 ± 133) atoms/kg/day for 39Ar, (56.7 ± 7.5) atoms/kg/day for 37Ar in underground argon, and (92 ± 13) atoms/kg/day for 37Ar in atmospheric argon.},
doi = {10.1103/PhysRevC.100.024608},
journal = {Physical Review. C, Nuclear Physics},
number = 2,
volume = 100,
place = {United States},
year = {2019},
month = {8}
}