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Abstract

In the search for dark matter, detectors have been built over the last years which use liquid xenon as a detection medium. For them, ²²²Rn and its daughter nuclides pose a dangerous background source, as they can cause signals which look like those expected from dark matter particles. Consequently, it is important to understand, how ²²²Rn decay chain signals can be identified. As a result, this thesis is dedicated to looking for such signals in two detectors. One of them is the XENON100 detector, which belongs to the leading dark matter direct detection experiments. ²²²Rn decay chain event rates are used here for quantifying the effectiveness of using distillation techniques to separate radon from xenon. The other detector is called HeidelbergXenon (HeXe), and has been recently built at the Max-Planck-Institut für Kernphysik in order to study the decays of ²²²Rn and its daughter nuclides in liquid xenon. To achieve this task, a data processor is developed and tested over the course of this thesis. Also, the electronics equipment as well as the photosensors used for measuring with HeXe are characterized. Finally, HeXe data, taken with radon-enriched xenon, is analyzed to look for ²²²Rn decay chain events.