Construction of the Belle II TOP counter
2017 November 22
2017 November 24
The Belle II experiment operating at SuperKEKB of the luminosity frontier accelerator will perform high precision flavor physics measurements. An efficient particle identification is essential for Belle II to extend its reach toward new physics, and it is realized by the TOP counter. The TOP counter is a novel ring imaging Cherenkov detector, which measures the time of propagation (TOP) of the internally reflected Cherenkov photons. The TOP counter mainly consists of a quartz optics, micro-channel-plate photomultiplier tubes and front-end electronics. After the long R&D of more than a decade, we succeeded in producing those components, assembling the 16 TOP counter modules and finally installing them in 2016. That is one of the biggest milestones of the Belle II construction. This article reviews the TOP counter in terms of the production of each component and the construction.