Hamamatsu’s 20-inch PMT receives IEEE Milestone recognition for technical achievement


Hamamatsu, Japan – October 15, 2014 – Hamamatsu Photonics K.K. has been recognized by IEEE (Institute of Electrical and Electronics Engineers, corporate headquarters: New York, NY), the world’s largest professional organization for the advancement of technology in the areas of electronics, information technology and telecommunications, for technical achievement in the development of the 20-inch photomultiplier tube (PMT), which has been used for the observation of phenomena such as supernovas and neutrinos. The 20-inch PMT was originally developed by Hamamatsu at the request of Masatoshi Koshiba (Professor Emeritus, University of Tokyo), who jointly won the 2002 Nobel Prize in Physics for his research on the detection of cosmic neutrinos. Initially, hundreds of the 20-inch PMTs were manufactured and installed in the Kamioka Proton Decay Experiment. Subsequently, over ten thousand 20-inch PMTs were installed in the Super-Kamioka Neutrino Detection Experiment.


For its contribution to the observation of neutrinos, the 20-inch PMT has been certified as an IEEE Milestone, which IEEE describes as an award that recognizes “technological innovation and excellence for the benefit of humanity found in unique products, services, seminal papers and patents” in one of the technical areas represented by IEEE.



IEEE Milestone accreditation

Title : 20-inch Diameter Photomultiplier Tubes, 1979 - 1987
Reason :
Hamamatsu Photonics K.K. began developing 20-inch diameter photomultiplier tubes at Toyooka Factory in 1979 for a 3000-ton water-filled Cherenkov particle detector, Kamiokande-II, in response to a request by Professor Masatoshi Koshiba. 1071 PMTs on it collected photons induced in the water by the particles falling on it. Kamiokande-II detected a neutrino burst in the Supernova SN1987A in 1987, earning Professor Koshiba a Nobel Prize in 2002.


20-inch PMT designed for Kamiokande

20-inch PMT designed for Kamiokande

IEEE MIlestone unveiling ceremony

IEEE Milestone unveiling ceremony


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