Radon background in liquid xenon detectors

TL;DR

This paper reviews the challenge of radon-222 contamination in liquid xenon detectors, discussing its sources, impact on experiments, and strategies for mitigation through material selection and active removal methods.

Contribution

It provides a comprehensive overview of radon mitigation techniques specifically tailored for liquid xenon detectors used in rare event searches.

Findings

Radon-222 can mimic signal events in xenon detectors.

Material selection and on-line removal are key mitigation strategies.

Radon background could dominate in future large-scale experiments.

Abstract

The radioactive daughters isotope of 222Rn are one of the highest risk contaminants in liquid xenon detectors aiming for a small signal rate. The noble gas is permanently emanated from the detector surfaces and mixed with the xenon target. Because of its long half-life 222Rn is homogeneously distributed in the target and its subsequent decays can mimic signal events. Since no shielding is possible this background source can be the dominant one in future large scale experiments. This article provides an overview of strategies used to mitigate this source of background by means of material selection and on-line radon removal techniques.