Discriminating the muon noise at the PMT windows in calorimeters

In particle physics experiments, stray muons are known to be a source of anomalous signals when they produce Cherenkov photons in the PMT window. Most recent of such events were reported by CMS Hadronic Forward calorimeters, where PMTs read out the Cherenkov signal generated within the quartz fibers. This study focuses on finding an efficient way to discriminate the Cherenkov signal coming from the quartz fibers from the ones generated at the face of the PMT due to stray muons. We report that these two different signals can be discriminated based on their pulse widths. The study also shows the performance of a proof-of-concept circuit prototype that effectively tags the two types of pulses.