Observation of radon mitigation in MicroBooNE by a liquid argon filtration system

The MicroBooNE Collaboration

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The MicroBooNE liquid argon time projection chamber (LArTPC) maintains a high level of liquid argon purity through the use of a filtration system that removes electronegative contaminants in continuously-circulated liquid, recondensed boil off, and externally supplied argon gas. We use the MicroBooNE LArTPC to reconstruct MeV-scale radiological decays. Using this technique we measure the liquid argon filtration system's efficacy at removing radon. This is studied by placing a 500 kBq 222Rn source upstream of the filters and searching for a time-dependent increase in the number of radiological decays in the LArTPC. In the context of two models for radon mitigation via a liquid argon filtration system, a slowing mechanism and a trapping mechanism, MicroBooNE data supports a radon reduction factor of greater than 97% or 99.999%, respectively. Furthermore, a radiological survey of the filters found that the copper-based filter material was the primary medium that removed the 222Rn. This is the first observation of radon mitigation in liquid argon with a large-scale copper-based filter and could offer a radon mitigation solution for future large LArTPCs.

Original languageEnglish (US)
Article numberP11022
JournalJournal of Instrumentation
Volume17
Issue number11
DOIs
StatePublished - Nov 1 2022

Keywords

  • Counting-gas and liquid purification
  • Gas systems and purification
  • Noble liquid detectors (scintillation, ionization, double-phase)
  • Time projection Chambers (TPC)

ASJC Scopus subject areas

  • Instrumentation
  • Mathematical Physics

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