Design and construction of a new detector to measure ultra-low radioactive-isotope contamination of argon

Understand

Large liquid argon detectors offer one of the best avenues for the detection of galactic weakly interacting massive particles (WIMPs) via their scattering on atomic nuclei.

• The liquid argon target allows exquisite discrimination between nuclear and electron recoil signals via pulse-shape discrimination of the scintillation signals.
• Atmospheric argon (AAr), however, has a naturally occurring radioactive isotope, $^{39}$Ar, a $\beta$ emitter of cosmogenic origin.
• For large detectors, the atmospheric $^{39}$Ar activity poses pile-up concerns.