A study of the trace 39Ar content in argon from deep underground sources

• Published in: Astroparticle physics Vol. 66; pp. 53 - 60
• Main Authors: Xu, J., Calaprice, F., Galbiati, C., Goretti, A., Guray, G., Hohman, T., Holtz, D., Ianni, An, Laubenstein, M., Loer, B., Love, C., Martoff, C.J., Montanari, D., Mukhopadhyay, S., Nelson, A., Rountree, S.D., Vogelaar, R.B., Wright, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2015
• Subjects: 39Ar; Dark matter instrumentation; Low-background counting; Low-radioactivity technique; Underground argon; Low-background counting; Dark matter instrumentation; Underground argon; Low-radioactivity technique; 39Ar
• ISSN: 0927-6505; 1873-2852
• DOI: 10.1016/j.astropartphys.2015.01.002

The discovery of argon from deep underground sources with significantly less 39Ar than atmospheric argon was an important step in the development of direct dark matter detection experiments using argon as the active target. We report on the design and operation of a low-background single-phase liquid argon detector that was built to study the 39Ar content of this underground argon. Underground argon from the Kinder Morgan CO2 plant in Cortez, Colorado was determined to have less than 0.65% of the 39Ar activity in atmospheric argon, or 6.6mBq/kg specific 39Ar activity.