Mechanical Design of the Belle II Silicon Vertex Detector

Autoren: Immanuel Gfall
Gruppe: Theorie DM
Kategorie: Masters-Thesis

The Belle 2 detector is a particle physics experiment located in Tsukuba, Japan. The entire experiment is currently redesigned to reach a 40 times higher luminosity to increase statistics for rare decay events. This higher luminosity requires a comprehensive improvement of several components. One of the central components is the Silicon Vertex Detector (SVD). This thesis reflects the author's approach on a mechanical design of the silicon sensor support structure. The scope of the work covers aspects of physics as well as physical requirements, design and prototype production. The design is not final and there are a few issues that have to be resolved around it. Thus this thesis only covers the current state which is likely to be outdated in the future.

The design started with a single question: "How does a structure have to be built to be mechanically rigid but lightweight and as transparent as possible for low energy particles?" This thesis shows that the options are limited due to the given constraints. The most dominant question in the design still is: "How do I manage the tight space constraints without structural intersections of adjacent detector layers?" This question also implies a proper cabling and cooling design. The cooling design is essential to transport the heat dissipated by the front-end electronics out of the tight SVD confinement and thus has to be highly efficient. This thesis will also cover cooling basics and the reasons why the author chose a CO2 cooling scheme. The conclusion of this work will provide simulation results and mock-ups to show that the design is feasible from a physics point of view.