Development of large area UV-sensitive MPPCs to detect scintillation light from liquid xenon

The MEG experiment searches for new physics like SUSY-GUT/SUSY-seesaw through lepton flavor violating μ⁺ → e⁺γ decay. In order to improve the experimental sensitivity, the detector upgrade project (MEG II) is underway. The 900 liter of liquid xenon (LXe) detector with 846 2 PMTs measures energy, timing, and position of 52.8MeV gamma-ray. The finite size of the PMT produces non-uniform response against events which interact close to the gamma-ray incident face. In MEG II, the PMTs at the incident face will be replaced with new smaller photo sensors. We have developed large area VUV-sensitive MPPC with HPK for this purpose. In this April, 600 prototype MPPCs are produced, and basic properties at room temperature were measured. Here the test results and upcoming measurements at LXe temperature as well as the prospects are described.