Ultra-sensitive photosensors with a diameter of 50 cm are used in the Hyper-Kamiokande. The photosensor has adequate water pressure resistance for use in water of the detector, and installing photosensor cover will increase safety.
Hyper-Kamiokande is an international research collaboration, with various countries sharing the research and development work. The Spanish group is playing a central role in the development and realization of the cover. The cover is currently being developed and is expected to be completed by 2021, with mass production beginning in 2022.