  PandaX-4T, the new generation of the PandaX detector, is a xenon dual-phase
detector with about six tons of liquid xenon as target for dark matter search.
A cryogenics and xenon handling system is designed to liquify and purify this
large detector. In this paper, the results on the commission of the cryogenics
and gas handling system are reported. The maximum cooling power of ~ 580 W at
178 K with three cooperating coldheads has been achieved. The filling rate with
an assisted liquid nitrogen cooling can reach ~ 700 kg/day. The average rate of
recuperation by liquid nitrogen is around 440 kg/day. The maximum total
purification speed of two circulation loops is up to ~ 155 slpm. Each loop is
using a large heat exchanger with a measured heat exchange efficiency of ~
97.5+-0.5%.
