LIQUID XE DETECTOR FOR MU E GAMMA SEARCH K. OZONE

A new type of liquid Xe detector has been developed for an experiment searching for µ+ → e+γ at Paul Scherrer Institute(PSI). The detector utilizes liquid xenon as a scintillation material. The scintillation light are observed by photomultiplier tubes(PMTs) immersed in liquid xenon. The performance of the detector has been investigated with two prototypes. The first prototype with an active volume of 2.3 liter viewed by 32 PMTs was tested by using radioactive γ-ray sources of 0.3 MeV to 1.8 MeV. From the first prototype results, it is expected that ∼1 %(r.m.s.) for energy resolution for 52.8-MeV γ, a few mm for position, and 50 psec for time will be obtained. The second larger prototype has already constructed, which has an active volume of 68.6 liter viewed by 228 PMTs. The second prototype is now undergoing all the necessary tests for construction of a final detector using Compton backscattered γ-rays up to 40 MeV.