The Low-Radioactivity Underground Argon Workshop took place on March 19-20, 2018 at Pacific Northwest National Laboratory in Richland, Washington, USA.

In response to the growing need for low-radioactivity argon, Pacific Northwest National Laboratory hosted a 2-day workshop to bring together community experts and interested parties to discuss the worldwide low-radioactivity argon needs and the challenges associated with its production and characterization.

The topic areas included:

• Experiment requirements/needs
  • Quantity, radiopurity, time-scale, chemical purity, isotopic composition
• Sources & Signatures of low-radioactivity argon
  • Sources of low-radioactivity underground argon
  • Signatures for low-radioactivity argon in underground sources
  • Underground production of radioactive argon isotopes (³⁷Ar, ³⁹Ar, & ⁴²Ar)
  • Cosmogenic production of radioactive argon isotopes (³⁷Ar, ³⁹Ar, & ⁴²Ar)
• Large scale production and isotope separation
  • Extraction & Purification
  • Isotope separation
  • Quality Assurance – Measuring radioactive argon infiltration (e.g. air contamination)
• Measuring low levels of ³⁷Ar, ³⁹Ar, & ⁴²Ar