Preparations for the Proton-Radius Measurement at AMBER and Operation of Silicon-Microstrip Detectors at COMPASS

The charge radius of the proton can be determined by measuring the slope of the electric form factor $G_E$ at small squared four-momentum transfer $Q^2$ Numerous elastic scattering and laser spectroscopy measurements of the proton radius have been performed with contradicting results —the so-called $proton$ $radius$ $puzzle.$ Within this thesis, substantial contributions have been worked out for the proposal to measure the proton radius in high-energy elastic muon-proton scattering at the M2 beam line of CERN’s Super Proton Synchrotron going back to Prof. S. Paul. Originally being part of an addendum to the program of the COmmon Muon Proton Apparatus for Structure and Spectroscopy (Compass) collaboration written in the year 2018, it has now been taken over in the new Apparatus for Meson and Baryon Experimental Research (Amber) collaboration. The high-precision measurement at low $Q^2$ is realized with a high-pressure hydrogen Time Projection Chamber (TPC), a technology developed and contributed by the Petersburg Nuclear Physics Institute (PNPI) and being envisaged also for a sister experiment at Mainzer Mikrotron (MAMI). This allows a new view on the systematics compared to electron scattering. The core setup consists out of silicon and scintillating fiber tracking detectors up- and downstream of the TPC and a novel streaming Data Acquisition (DAQ) to combine the drift time of the TPC with fast tracking detectors. A beam test of a new unified tracking station utilizing scintillating fibers and monolithic pixel-silicon detectors and commissioning of the novel DAQ system are foreseen during 2022 as preparation for an envisaged physics run starting mid of 2023. Simulations and analysis of the final setup are performed within this thesis. Evaluation of the redundant measurement of the scattering kinematics at a comparable precision show the capability of extracting the radius with an absolute precision < 1 %. Optimizations of the geometry and material budget for the Unified Tracking Station (UTS) and TPC construction are achieved to reach this level of precision. Within this thesis, the organization of a feasibility test measurement in the year 2018 and results of the ongoing analysis are presented. After a thorough selection of scattered muon events, a timestamp-based matching between tracking and TPC data is used to extract kinematic relations, i.e., the kinetic energy of the recoil proton and muon scattering angle. This timestamp approach is used as predecessor of the novel DAQ system to verify the capability of the combined data taking of tracking and TPC. Based on these results, fundamental insights to the Letter of Intent (LoI) and the subsequent proposal for the proton radius measurement within the novel Amber collaboration are contributed. Muon-electron scattering as intended calibration channel for momentum reconstruction is evaluated as being part of the obtained data set. As part of this work, a pilot run in 2021 as requirement for an anticipated physics run was organized. It is described together with initial goals set in close communication with CERN’s Super Proton Synchrotron Committee (SPSC). With a similar approach as the feasibility test in 2018 a close-to-final setup geometry was constructed. Silicon-microstrip tracking detectors and a down-scaled version of the final TPC is used with the timestamp-based approach to extract correlated events for ongoing studies of the TPC energy resolution in the muon beam. As a second part of this thesis, the author was responsible for the setting up and operating the existing silicon-microstrip detectors during the Compass data takings in 2016 to 2022 and their employment for the proton-radius-related beam tests for Amber in 2018 and 2021. Besides upgrades of the used cooling system, required time calibrations have been created and improved and the performance of the detectors is evaluated during those years.