Design, construction, and testing of the PandaX-xT cryogenics system

TL;DR

The paper details the design, construction, and testing of a large-scale cryogenics system for the PandaX-xT experiment, enabling efficient and safe handling of 43 tons of liquid xenon for dark matter and neutrino research.

Contribution

It introduces a novel cryogenics system with dual cooling towers and emergency nitrogen cooling, optimized for large-scale liquid xenon detectors.

Findings

Achieved 1900 W cooling power at 178 K with two cooling towers.

Liquid nitrogen coil provides emergency cooling >1500 W at xenon temperature.

Maintained xenon vapor pressure fluctuation below 1 kPa over a month.

Abstract

The PandaX-xT is a next-generation experiment with broad scientific goals, including the search for dark matter, Neutrinoless Double Beta Decay, and astrophysical neutrinos, using a dual-phase time projection chamber with about 43 tons of liquid xenon. A new cryogenics system of the PandaX-xT is described in this paper. It is developed to handle large mass of liquid xenon efficiently and safely, including two cooling towers for normal operation and one liquid-nitrogen coil for emergency case. Each cooling tower equipped with an AL600 Gifford-McMahon cryocooler features a 1300 W heater, specifically designed to maintain the cold finger's temperature at the desired setpoint. The performance of the cooling tower and the coil has been tested. The cryogenics system with two cooling towers has achieved about 1900~W cooling power at 178~K. The liquid nitrogen coil provides emergency cooling power of more than 1500~W at liquid xenon temperature. For the prototype of a 1-tonne liquid xenon detector, the fluctuation of xenon saturated vapor pressure remains below 1 kPa over one month, while the pressure is around 210~kPa.