a few comments
Hamamatsu Photonics K.K. began developing 20-inch diameter photomultiplier tubes at Toyooka Factory in 1979 for a water-filled-Cherenkov elementary particle detector, Kamiokande-II. 1071 PMTs on it collected photons induced in the water by the elementary particles falling on it. Kamiokande-II detected a neutrino burst in the Supernova SN1987A in 1987, opening a window in astrophysics which earned Professor Masatoshi Koshiba a Nobel Prize in 2002.
I added "i" between "20-" and "nch". Otherwise we are happy with the revised citation as proposed.
We clearly understand that it is subject to change in the course of evaluating milestone nominations by the committee. It is fine by us.