Calibration Methods for the MEG Photon Detector

Full text: The goal of the MEG experiment (Paul Scherrer Institute, Switzerland) is to search for the lepton flavor violating decay μ→e+γ with a sensitivity of 10-13 in branching ratio. The photons are detected by the world's largest liquid Xenon scintillation detector. To achieve high-precision measurements of the photon properties (timing, position and energy) and to ensure a long-term operation of the detector at high performance, the calibration of the photon detector as well as its monitoring is crucial. An overview about the current established photon detector calibration methods as well as first results of the newest calibration method which uses a pulsed neutron generator and a Nickel absorber are presented. The neutron capture process produces a 9 MeV gamma emission which can be used to determine the photon detector stability very quickly even under variable beam conditions. (author)