A chromatographic system for removal of radioactive 85Kr from xenon

Extremely low count rates of useful events in detectors of neutrino or weakly interacting exotic particles require using detector working media with low levels of radioactive contaminants. Liquid xenon, highly purified and filtered using advanced semiconductor industry technologies serves as an attractive target for several modern experiments searching for cold dark matter, double beta decay, and detection of low energy neutrino. Separation of xenon from trace amounts of 85Kr cannot be achieved with commercially available gas purifiers. We have developed an automated system for purification of xenon from trace amounts of krypton. The system has been used to purify 25 kg of xenon to the level of < 3 ppt of krypton. The purified xenon will be used for the two-phase emission detector, XENON10, to search for WIMP dark matter in the Gran Sasso Underground Laboratory.