The EXO-200 experiment was conceived to search for neutrinoless double beta decay of 136Xe. The experiment was located 650 meters underground at the Waste Isolation Pilot Plant and was in operation from May 2011 until November 2018. The muon veto system in the EXO-200 experiment consisted of twenty-nine plas- tic scintillator panels that surrounded four out of six walls of the clean room that housed the EXO-200 time projection chamber. The veto system was needed to identify and reject prompt muon-induced backgrounds. Calibration measurements for EXO-200 muon veto panels were done to validate their operability and per- formance throughout the life of the experiment. I will present the process of con- ducting veto panel calibrations and cumulative results as of the last calibration campaign as well as veto effectiveness estimation.
Monitoring the health of EXO-200 muon veto panels