Development of a large volume zero boil-off liquid xenon storage system for muon rare decay experiment (MEG)

We have developed a new type of photon detector for an experiment aimed at searching for the lepton flavor violating decay μ+ → e+γ. In this experiment, a total of 900 L of liquid xenon is used in order for the scintillation detector to detect γ-rays with an extremely high sensitivity, where the liquid xenon is viewed by an array of 846 photomultipliers from all sides. The entire amount of xenon should be stored in certain storage systems before the start of the experiment, during detector maintenance in the period of accelerator shutdown, etc. We have developed a new liquid xenon storage system by employing the zero boil-off condition by using a pulse tube cryocooler. The details of system and its performance results are described in this article.