ETD

• monitor
• Mu2e
• proton
• reconstruction

Mu2e searches for neutrino-less coherent muon-electron conversion in the field of an aluminum nucleus and the signal is a monoenergetic electron of energy 105 MeV. The number of stopped muons is proportional to the number of protons on target, which itself depends on the extraction system for the proton beam. The Mu2e beam delivery system will use a resonant extraction to create the proton pulses and this method is characterized by intensity fluctuations on the time scale of milliseconds. These fluctuations, aside from the proportional fluctuation of the number of muons, have a non-trivial impact on the overall performance of the apparatus. The method we developed to monitor these fluctuations is based on counting the number of muons captured in the stopping target by counting the number of protons produced in the process of the nuclear muon capture. This is one of the possible processes a stopped muon can undergo and it can lead to the ejection of charged particles. The reconstruction algorithms were developed by the Mu2e collaboration with the aim to reconstruct tracks of electrons in an energy range of a conversion electron. The protons we are interested in behave quite differently from these electrons and the cardinal task of this study has been to tailor the reconstruction routines to these particles. Our results are satisfactory (approx. 4.5 tracks / 1.7 mus), and show that a monitor on the timescale of milliseconds is indeed possible.