What is the relationship between the professor and the company? If there is a link, it should be made explicit. Otherwise, I agree with ggcooke that other applications should be included, the professor not named, but you could mention it led to a nobel prize.
Also, please add commas before the non-restrictive "which" clauses.
Hamamatsu Photonics K.K. began developing 20-inch diameter photomultiplier tubes at Toyooka Factory in 1979 for a 3000-ton-water Cherenkov particle detector, Kamiokande-II, upon a request by Professor Masatoshi Koshiba. 1071 PMTs mounted on it collected photons induced in the water by the particles falling on it. It detected a neutrino burst in the Supernova SN1987A to bring him a Nobel Prize in Physics in 2002.
I would like to propose the above sentence for a revised version of the Plaque Citation, in responce to the question/comment by Allisonmarsh.