Speaker
Yasuhiro NISHIMURA
(The University of Tokyo)
Description
Hyper-Kamiokande is a large water Cherenkov detector planned in Japan
with improved photo-detectors. A 50 cm-diameter photomultiplier tube (PMT) was
initially developed for Kamiokande, and improved for Super-Kamiokande,
where a Venetian blind dynode was adopted for a wide acceptance.
Further improvement with a high charge and time resolutions was
achieved for Hyper-Kamiokande with a box-and-line dynode as an R12860
PMT by Hamamatsu Photonics K.K. The collection efficiency reaches 95%,
superior to 67% of the PMT in Super-Kamiokande. It also gives a higher
quantum efficiency of 30% at peak compared to a typical 22% for the Super-K PMT.
In addition, we developed a 50 cm-diameter hybrid photo-detector
(HPD), R12850 by Hamamatsu, with an avalanche diode that resulted in a higher
resolution and detection efficiency. A preamplifier and high voltage
module were designed to be equipped inside. Detailed performance
evaluation was performed with a stability measurement in a water tank.
Many accessories such as a cable, connector and cover, and alternative
candidates of photo-detectors for Hyper-Kamiokande are being
developed. The development and performance of the improved
photo-detectors will be presented.
Authors
Masashi Yokoyama
(University of Tokyo)
Yasuhiro NISHIMURA
(The University of Tokyo)
