Experimental Analysis of PandaX-4T Cryogenic Distillation System for Removing Krypton from Xenon

TL;DR

This paper presents the design, construction, and experimental validation of a cryogenic distillation system for PandaX-4T that effectively reduces krypton in xenon to ultra-low levels, supporting dark matter detection.

Contribution

It introduces a novel cryogenic distillation system based on the McCabe-Thiele method, achieving high purity xenon with efficient krypton removal for the PandaX-4T detector.

Findings

Achieved krypton concentration below 8 ppt in xenon

Produced 5.75 tons of ultra-high purity xenon

Demonstrated stable and efficient distillation performance

Abstract

An efficient cryogenic distillation system was designed and constructed for PandaX-4T dark matter detector based on the McCabe-Thiele (M-T) method and the conservation of mass and energy. This distillation system is designed to reduce the concentration of krypton in commercial xenon from 5X$10^{-7}$ mol/mol to $10^{-14}$ mol/mol with 99% xenon collection efficiency at a maximum flow rate of 10 kg/h. The offline distillation operation has been completed and 5.75 tons of ultra-high purity xenon was produced, which is used as the detection medium in PandaX-4T detector. The krypton concentration of the product xenon is measured with an upper limit of 8.0 ppt. The stability and purification performance of the cryogenic distillation system are studied by analyzing the experimental data, which is important for theoretical research and distillation operation optimization.