Preview

PDF, English Download (59MB) | Terms of use

Abstract

The Mu3e experiment is designed to search for the charged lepton flavour violating decay μ → eee with an ultimate single event sensitivity of 10−16 – four orders of magnitude better than the current best exclusion limit. In order to reach this sensitivity, excellent vertex, momentum, and timing measurements of the decay products are needed for the background suppression. With a timing resolution < 100 ps, the Tile Detector is designed to provide the most accurate timing information in the Mu3e experiment and is crucial for the suppression of combinatorial background. It consists of two barrels built in a modular approach and utilises plastic scintillator tiles, which are individually coupled to silicon photomultipliers read out by a custom ASIC. This thesis describes the design, construction, and thermal simulation of the Tile Detector from the prototype stage to production readiness. The construction of the first technical prototype proves the functionality of the detector concept, yielding a single-channel time resolution of ≈ 47 ps. With the technical prototype serving as a baseline, the Tile Detector design is adapted and optimised in order to simplify the construction on the one hand, and on the other hand to facilitate the mechanical integration into the experiment. In parallel, thermal simulations of the intermediate design stages of the cooling circuit ensure that the cooling capability is suitable for the Tile Detector requirements. Based on the finalised detector design, which was implemented in this work, a production line with custom tools and dedicated quality control procedures is developed and evaluated during the construction of two preproduction modules. Measurement campaigns are conducted to commission and tune the modules using first calibration procedures. After excluding all known and fixable errors, more than 96 % of the tested channels are fully functional. As a result, production readiness is achieved for the Tile Detector, paving the way for the full detector construction, installation and commissioning foreseen in 2024/2025.