Cryogenics for the LUX Detector

This paper describes results on R&D of an economical and efficient cryogenic system for the LUX detector. LUX is a new WIMP dark matter search experiment to be carried out at the Homestake (South Dakota) gold mine, and is based on 300 kg of liquid xenon (LXe) operated at a temperature of 175 K. The cooling system consists of a cold head attached to a thermal screen surrounding the cold vessel and three nitrogen-filled thermosyphons designed to transport heat loads to a free-boiling liquid nitrogen bath. The most powerful thermosyphon mounted directly onto the cold head has demonstrated > 1 kW cooling power and has been used for the initial cooling of the detector and xenon condensation. The second thermosyphon with ~ 0.2 kW cooling power is mounted to the cold head through a thermal impedance designed for stable operation of the detector when the condensation is completed. The third thermosyphon similar to the second one is connected to the bottom of the thermal screen to control the temperature gradient along the detector. Results of initial tests are presented.