Performance of the MUSE Beam Hodoscope

Inspired by the "Proton Radius Puzzle" of 2010, the MUon Scattering Experiment (MUSE) at the Paul Scherrer Institute(PSI) performs simultaneous ep and μp scattering using both charge polarities. A beam of e’s, μ’s and π’s and an assembly of targets and detectors are used to collect production data. The cross-section, form factors and proton radius measured using e and μ scattering can then be compared. Using both charge polarities directly determines two-photon exchange, which makes the opposite polarity cross-sections differ and impacts the determination of form factors and the proton radius. To obtain these measurements, it is of vital importance to have precise timing information for beam particles. The detector used for this task is the Beam Hodoscope (BH). The BH timing information is be used in conjunction with the accelerator RF signal to provide beam particle identification at low precision for the trigger and at high precision for the event analysis. Time of flight from the BH to the scattered particle scintillators determines the reaction type, in particular separating μ decays in flight from μ scattering. In this talk, we will describe the BH system and discuss its performance.