Constraining Radon Backgrounds in LZ

Abstract

The LZ dark matter detector, like many other rare-event searches, will suffer from backgrounds due to the radioactive decay of radon daughters. In order to achieve its science goals, the concentration of radon within the xenon should not exceed $2\mu$Bq/kg, or 20 mBq total within its 10 tonnes. The LZ collaboration is in the midst of a program to screen all significant components in contact with the xenon. The four institutions involved in this effort have begun sharing two cross-calibration sources to ensure consistent measurement results across multiple distinct devices. We present here five preliminary screening results, some mitigation strategies that will reduce the amount of radon produced by the most problematic components, and a summary of the current estimate of radon emanation throughout the detector. This best estimate totals $<17.3$ mBq, sufficiently low to meet the detector's science goals.

Low Radioactivity Techniques (LRT) 2017 Workshop Proceedings. 6 pages; 3 figures

References in corpus (5)

• Physics reach of the XENON1T dark matter experiment
• Measurements of extremely low radioactivity levels in BOREXINO
• Cosmogenic Backgrounds in Borexino at 3800 m water-equivalent depth
• Investigation of radioactivity-induced backgrounds in EXO-200
• Long-term study of backgrounds in the DRIFT-II directional dark matter experiment

Cited by in corpus (5)

• The LUX-ZEPLIN (LZ) radioactivity and cleanliness control programs
• Low Radioactive Material Screening and Background Control for the PandaX-4T Experiment
• Design and Commissioning of the PandaX-4T Cryogenic Distillation System for Krypton and Radon Removal
• Cryogenic bath-type heat exchangers for ultra-pure noble gas applications
• Ultra-clean radon-free four cylinder magnetically-coupled piston pump