Hyper-Kamiokande consists of two cylindrical tanks, each with a height of 48m and a length of 250m. The tanks are filled with 1 million metric tons of ultrapure water, a volume approximately 20 times larger than that of Super-Kamiokande and roughly corresponding to the total volume of the Tokyo Dome.
On the walls of the tanks, 99,000 ultrasensitive photo-sensors are installed, in order to detect the very weak Cherenkov light generated in the ultrapure water.
We have been developing the world’s largest photosensors, which exhibit a 50% higher photodetection efficiency than that of the Super- Kamiokande photosensors. These new photosensors are able to measure light intensity and its detection time with a much higher precision.