Speaker
Description
The SuperKEKB/Belle II experiment, the successor of the former KEKB/Belle experiment at KEK, has started its physics data taking with the full detector system since March 2019. The Time-of-Propagation (TOP) detector was designed and integrated into the Belle II detector for particle identification in the barrel region. The TOP detector consists of quartz radiators and photodetectors, Micro-Channel-Plate (MCP) PMT, and reconstructs a ring image of Cherenkov photons generated by an incident particle. It measures the timing of each detected photon with an accuracy of less than $100~\mathrm{ps}$ for good $K/\pi$ separation.
In the operation of the TOP detector, harsh beam-induced background in the high luminosity environment is one of the critical issues to achieve high performance. We have developed various tools to visualize MCP-PMT performance and to identify and fix errors arising from front-end electronics during data taking. The TOP detector provides 85% $K$ efficiency at a 10% $\pi$ misidentification rate in the data at the early stage of the experiment. In this talk, we will report the operation status and the performance by the summer of 2021.
| kojima@hepl.phys.nagoya-u.ac.jp | |
| Collaboration / Activity | Belle II Collaboration |
| First author | Kazuki Kojima |
