Speaker
Description
Hyper-Kamiokande (Hyper-K) is a next generation underground large water Cherenkov detector. Its tank will be filled with 260,000 metric tons of ultra-pure water with a fiducial volume of 0.19 Mtons, which is about 8 times larger than that of its predecessor Super-Kamiokande. In its water volume, Cherenkov light will be produced by neutrino interactions and detected by newly developed photo sensors installed in a dedicated frame.
Two different kinds of photo-detectors systems are considered for Hyper-K: 20-inch PMT and multi-PMT (mPMT). In particular, the mPMT system consists of a pressure sealed vessel with 19 3-inch PMTs installed inside. This configuration was implemented for the first time in the KM3NeT experiment, and has been demonstrated to improve the Hyper-K physics capabilities. A mPMT Optical Module is instrumented with a readout electronic system and a power circuit for the PMTs and electronics. The mPMTs offer several advantages over the standard 20-inch PMTs, i.e., increased granularity, reduced dark rate, weaker sensitivity to Earth’s magnetic field, improved timing resolution and directional information with an almost isotropic field of view.
Hyper-K will be located in the Kamioka mine (Japan), where a dedicated cavern under a 600m-high mountain is being excavated for the installation of the detector. This configuration reduces the cosmic muon flux and its spallation products, which are the dominant background sources for analyses of low-energy astrophysical neutrinos. With its fruitful physics research program, Hyper-K will play a highly significant role in the next neutrino physics frontier, including the neutrino astrophysics program, providing important information from its measurements.
The development of a mPMT module for Hyper-K and the physics potential of the Hyper-K neutrino astrophysics program will be discussed in this contribution.
