XENON Dark Matter Search Experiment

Principle



As shown above, the LXeTPC module containing the active xenon target is formed by a sandwich of Teflon spacers (UV diffuse reflector) and copper rings for electric field shaping. The structure is closed at the bottom by a copper plate, which is coated with CsI to convert Xe scintillation photons into free electrons. The structure forms a 30 cm high cylinder with 38 cm inner diameter, holding about 100 kg of ultra pure liquid xenon.

On the top, the structure is hermetically sealed with a cylindrical copper vessel of larger diameter, housing the PMTs and the wire structure for the proportional scintillation process in the gas phase. The LXeTPC structure is enclosed in a copper vessel containing the liquid xenon for active shielding. With both detectors at the same temperature and similar pressure, the amount of material for the inner detector walls is minimized. The scintillation light from the shield section is viewed by two rings of 16 PMTs each.