Speaker
Description
The Mu3e detector is under construction at the Paul Scherrer Institute. It aims to set a limit on the observation of the SM forbidden lepton flavour violating mu->e+e-e- decay. As an integral part of its design, it incorporates a state-of-the-art depleted monolithic pixel sensor tracking system, comprising an inner vertexing barrel and outer tracking system. These detectors achieve a 0.1% X/Xo radiation length and incorporate aggressively thinned silicon, SPTab bonded Al/kapton readout flexible circuits and 25um composite mechanical supports.
The contribution will explore the physics motivation of the design of the pixel system, and discuss the unusual material constrains this-places on the detector, particularly the reconstruction of the momentum of low energy electrons. We will report on the technical challenges that have been overcome in the final prototyping stages, and the move into full detector module serial production and installation. Specifically, we will explore the design difficulties in the close integration of the mechanical and electrical components, the choice of the electrical interconnect technology, the issues involved in quality control testing of 6,000 70um thick Mupix11 monolithic silicon pixel sensors, the late change to a composite material for supports, and the further development towards functionally engineered composite meta-materials. We will discuss how the technology developments and lessons learned are applicable to future low mass tracking systems. Finally, we will also look forward and discuss plans for the initial commissioning and data taking period at the end of 2026 and the initial Phase1 physics running in 2027.