Kun Wan ; Hiroaki Aihara

2017
University of Tokyo Tokyo

Abstract: Belle II experiment is a next generation B-factory that is aimed to study many excit- ing and intriguing topics in the research of New Physics, located in Tsukuba, Japan. It is expected to collect around 50 times more data than its predecessor, Belle, mostly thanks to 40 times higher luminosity provided by SuperKEKB over the original KEKB accelerator, which naturally raises the new requirements on both hardware and soft- ware in detector. SVD is composed of 4 layers strip detectors in Belle II for spatial precise tracking and vertex fitting. Its excellent performance is extremely important to the success of Belle II. In this thesis, the feasibility study of using charge correlation on P and N types of semiconductor to reject the ghost hits will be presented. It will mainly benefits the correct vertexing of particles decay and fast filtering in SuperKEKB environment. The general information and the significance of Belle II experiment will be introduced in Chapter 1. In order to have a comprehensive understanding of this topic, both hardware and tracking software features about SVD are instructively implemented in chapter 2 and 3. For closely approaching the real experiment, beam test data was taken in DESY using one SVD ladder at 2∼6 GeV beam energy. A few observable quantities like asymmetry of P&N charges are studied to searching for a formula of hits purity, presenting probability of a hit being real. These relative content will be illustrated in Chapter 4 and 5. As the beneficial outcome of this study, the correctness of SVD simulation of charge sharing on floating strips is largely improved, contributing to the offline calibration of SVD clusters. All relative work and results will be included as part of SVD group contribution in Belle II.

Note: Presented on 21 07 2017
Note: MSc