2008.07.11
Obituary: Yoji Totsuka, Former Director General of KEK

Yoji Totsuka, the former director general of KEK and an outstanding contributor to great advances in neutrino physics, died of cancer at the age of 66 on Thursday, July 10.

Totsuka was one of the first-generation of students to study under Professor Koshiba, the 2002 Nobel Prize Laureate in Physics, at the graduate school of the University of Tokyo. Upon receiving his Ph.D. degree in 1972, Totsuka began his career working on DASP, an electron-positron collider experiment in DESY, Hamburg, as a research associate of the University of Tokyo. Later he joined other experiments including JADE. In 1981, Totsuka was called back to Japan by Koshiba, to build Kamiokande, a large water Cerenkov detector. In 1988, he took over the role of Kamiokande spokesperson from Koshiba, and led the design and construction of Super-Kamiokande, which brought him and his colleagues to the discovery of atmospheric neutrino oscillations in 1998. In October 2002, he moved to KEK and worked as the director general from 2003 to 2006. He was a professor emeritus of KEK and the University of Tokyo.

He received numerous awards: Asahi Prize - Kamiokande (1988), Nishina Memorial Prize (1987), Bruno Rossi Prize (1989), Asahi Prize - Super-Kamiokande (1999), Purple Ribbon Medal (2001), Fujiwara Prize (2002), Panofsky Prize (2002), Culture Merit (2002), Order of Culture (2004), Bruno Pontecorvo Prize (2004) and Franklin Institute Awards (2007).

I had worked with him in Kamiokande and Super-Kamiokande for more than 20 years. We started the design and construction of Kamiokande and then the upgrad to Kamiokande-II and -III. In the meantime, we had a very enjoyable time observing the neutrino bursts from SN1987A, confirming the solar neutrino problem and detecting the atmospheric neutrino anomaly. These physics outcomes blew off the tight and heavy workload during the Kamiokande upgrade. In parallel to such Kamiokande activities, he led the design and development of the Super-Kamiokande detector.

We had many discussions and sometimes quarrels. His very straightforward nature always gave us a friendly atmosphere and encouragement. I remember one winter night at Kamioka in ~1990, where we were drinking alcohol as usual. We had an urgent phone call from the university (originally from the government) which asked us to come up with 10 items concerning the usefulness of Super-Kamiokande to the human life within one hour. This type of question from the government implied that the budget approval of Super-Kamiokande was coming up. Thanks to alcohol, we could make up (frame-up) eccentric ideas for the inquiry. As Super-Kamiokande was growing into a big enterprise from a small company, Kamiokande, he exercised excellent leadership, and led the discovery of atmospheric neutrino oscillations.

He was a prominent leader both in non-accelerator and accelerator neutrino experiments. He established the financial and international organization schemes for K2K and T2K, accelerator based long baseline neutrino oscillation experiments. He was also very proactive in pushing foward international cooperation as members of many large particle laboratories. He was a completely outstanding physicist.