Removal of noble gases from xenon by cryogenic distillation

The operating XENON1T experiment, located in the Laborati Nazionali del Gran Sasso (LNGS), utilizes about 3.3 tons of liquid xenon for the direct detection of dark matter in the form of Weakly Interacting Massive Particles (WIMPS). A key requirement to reach the desired sensitivity is the removal of intrinsic radioactive backgrounds such as Kr-85 and Rn-222, which create WIMP-like signals within the innermost of the detector. By employing the differences in vapor pressure between krypton and radon with respect to xenon, a cryogenic distillation column is used to reduce such noble gas impurities. This talk presents an overview of the performed distillation campaigns at XENON1T and discusses possible improvements for the future XENONnT experiment. Different aspects of this project have been funded by DFG Grossgeraete, BMBF and Helmholtz-Alliance for Astroparticle Physics (HAP).