  Panda-X is a liquid xenon dual-phase detector for the Dark Matter Search. The
first modestly-sized module will soon be installed in the China JinPing Deep
Underground Laboratory in Sichuan province, P.R. China. The cryogenics system
is designed to handle much larger detectors, even the final version in the ton
scale. Special attention has been paid to the reliability, serviceability, and
adaptability to the requirements of a growing experiment. The system is cooled
by a single Iwatani PC150 Pulse Tube Refrigerator. After subtracting all
thermal losses, the remaining cooling power is still 82W. The fill speed was 9
SLPM, but could be boosted by LN2 assisted cooling to 40 SLPM. For the
continuous recirculation and purification through a hot getter, a heat
exchanger was employed to reduce the required cooling power. The recirculation
speed is limited to 35 SLPM by the gas pump. At this speed, recirculation only
adds 18.5 W to the heat load of the system, corresponding to a 95.2 %
efficiency of the heat exchanger.
