# EPS-HEP2021 conference

26-30 July 2021
Zoom
Europe/Berlin timezone

## The operation and performance of the TOP detector at the Belle II experiment

26 Jul 2021, 16:00
15m
Zoom

#### Zoom

Parallel session talk Detector R&D and Data Handling

### Speaker

Kazuki Kojima (BELLE (BELLE II Experiment))

### 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.

Email kojima@hepl.phys.nagoya-u.ac.jp Belle II Collaboration Kazuki Kojima

### Primary author

Kazuki Kojima (BELLE (BELLE II Experiment))