Hyper-Kamiokande is the next generation Water Cherenkov detector that is being developed by an international collaboration as a leading worldwide experiment based in Japan. It will address the biggest unsolved questions in physics through a multi-decade physics program that will start in the middle of the next decade. The Hyper-Kamiokande detector will be the largest underground water Cherenkov detector in the world. It will be hosted in the Tochibora mine, about 295 km away from the J-PARC proton accelerator research complex in Tokai, Japan.
A summary of an extensive R&D program will be presented, which covers two crucial aspects of the planned detector - photosensors and associated front-end electronics. Results of studies for various candidate photosensors will be presented, both for inner and outer detector volume. Tested sensors include a 50 cm Hamamatsu R12860-HQE photomultiplier tube (current baseline for inner detector), a 50 cm Hamamatsu R12850-HQE hybrid photodetector, a 50 cm MCP-PMT from NVT, multi-PMT module, 3” PMTs for both multi-PMT and one of the variants of the outer detector. In addition, a summary of current status of protective cover design will be provided. Finally, a short overview of various R&D activities related to front-end electronics design will be shown.