MaPMT Relative Efficiency Measurements for the LHCb RICH Upgrade

The Large Hadron Collider beauty experiment (LHCb) at CERN is aimed to study flavor-physics. The Ring Imaging Cherenkov detector system (RICH), which provides particle identification, have been operating successfully since 2010. During the second Long Shutdown of the LHC of 2019–2020, the RICH detectors will be upgraded to maintain the excellent PID performance with a five-fold increase of instantaneous luminosity. In addition, the detector will be readout at the full LHC bunch-crossing rate of 40 MHz using a flexible software based trigger. To cope with that changes the current hybrid photon detectors will be replaced by Hamamatsu R13472 multi-anode photomultipliers (MaPMT) with external brand new frontend electronics. The new photodetectors and the associated electronics have been subjected to calibration procedures. The high-voltage working point determination, relative efficiency measurements of MaPMT pixels and their calibration procedure for the RICH detector system will be presented.