Speaker
Tadaki Ichikawa
(Nagoya university)
Description
The Belle II detector TOP counter is a particle identification device consisting of a quartz radiator and a Micro-Channel-Plate Photomultiplier tube (MCP-PMT). The identification performance depends on the quantum efficiency (QE) of the MCP-PMT, which decreases as the integrated output charge increases, but the QE measured from the physics run data decreased faster than expected. As a possible cause, we consider degradation of the photocathode due to ions inside the MCP. In this study, we aim to suppress the generation of ions while maintaining the performance of the MCP-PMT by optimizing the voltage application ratio inside the MCP-PMT.
