Koshiba, Masatoshi (1926- )

Japanese physicist who was awarded the 2002 Nobel Prize for Physics (with US radiochemist Raymond Davis, Jr, and Italian-born US astrophysicist Riccardo Giacconi) for his contributions to the field of astrophysics, especially for his work in the detection of neutrinos.

Studying neutrinos from the sun and from supernova explosions, Koshiba built the giant water tank detector Kamiokande which was housed in the bottom of a mine in Japan. It was used to expand upon Raymond Davis's work and proved the direction from which the neutrinos had come had been from the sun. In 1987, Koshiba was able to detect 12 of the neutrinos that had been generated by a supernova explosion. His discoveries led to the formation of the new field of scientific research, neutrino-astronomy.

Masatoshi was professor of physics at the University of Tokyo, Japan, from 1970 until he retired in 1987.