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arXiv · 2306.05673

Characterization of a $^{220}$Rn source for low-energy electronic recoil calibration of the XENONnT detector

Florian Jörg·Shengchao Li·Jochen Schreiner·Hardy Simgen·Rafael F. Lang
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Abstract

Low-background liquid xenon detectors are utilized in the investigation of rare events, including dark matter and neutrinoless double beta decay. For their calibration, gaseous $^{220}$Rn can be used. After being introduced into the xenon, its progeny isotope $^{212}$Pb induces homogeneously distributed, low-energy ($<30$ keV) electronic recoil interactions. We report on the characterization of such a source for use in the XENONnT experiment. It consists of four commercially available $^{228}$Th sources with an activity of 55 kBq. These sources provide a high $^{220}$Rn emanation rate of about 8 kBq. We find no indication for the release of the long-lived $^{228}$Th above 1.7 mBq. Though an unexpected $^{222}$Rn emanation rate of about 3.6 mBq is observed, this source is still in line with the requirements for the XENONnT experiment.

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Florian Jörg, Shengchao Li, Jochen Schreiner, Hardy Simgen, Rafael F. Lang. 2023-06-09. Characterization of a $^{220}$Rn source for low-energy electronic recoil calibration of the XENONnT detector. https://doi.org/10.1088/1748-0221%2F18%2F11%2Fp11009

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