Speaker
Description
The XENON collaboration employs dual-phase xenon time-projection chambers to search for weakly interacting massive particles (WIMPs) and other rare processes. In order to achieve high sensitivity to the WIMP-nucleon cross-section, radioactive contaminants must be carefully monitored and suppressed. One impurity particularly difficult to remove is krypton, presenting a significant challenge as signals induced by the β-decay of $^{85}$Kr leak into the ROI for dark matter searches. A cryogenic distillation column was developed for the XENON1T experiment, lowering the $^\text{nat}$Kr/Xe concentration and thus making the $^{85}$Kr background subdominant compared to the contamination from the radon decay chain.
During preparation for the XENONnT experiment, the xenon inventory was cleaned and a $^\text{nat}$Kr/Xe concentration of $(56\pm 36)\,$ppq was reached with an online distillation mode for the first sience run of XENONnT. This poster will present the cryogenic krypton distillation column and demonstrate its use cases with the current XENONnT experiment.
The project is funded by BMBF under contract 05A20PM1.
| Submitted on behalf of a Collaboration? | Yes |
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