An atom trap trace analysis system for measuring krypton contamination in xenon dark matter detectors

TL;DR

This paper presents a highly sensitive atom trap trace analysis system capable of detecting krypton contamination at parts per trillion levels in xenon, crucial for advancing dark matter detector sensitivity.

Contribution

The authors developed a novel ATTA system optimized for krypton detection in xenon, achieving ppt sensitivity within a few hours, enhancing dark matter detection capabilities.

Findings

Achieved detection sensitivity of ppt levels of Kr in Xe

System efficiency measured at 1.2 x 10^-8

Detection time less than 2 hours for target sensitivity

Abstract

We have developed an atom trap trace analysis (ATTA) system to measure Kr in Xe at the part per trillion (ppt) level, a prerequisite for the sensitivity achievable with liquid xenon dark matter detectors beyond the current generation. Since Ar and Kr have similar laser cooling wavelengths, the apparatus has been tested with Ar to avoid contamination prior to measuring Xe samples. A radio-frequency (RF) plasma discharge generates a beam of metastable atoms which is optically collimated, slowed, and trapped using standard magneto-optical techniques. Based on the measured overall system efficiency of $1.2 \times 10^{-8}$ (detection mode) we expect the ATTA system to reach the design goal sensitivity to ppt concentrations of Kr in Xe in $<2$ hours.