It is with great sadness that KEK announces the passing of Professor Yoshitaka Kimura, Professor Emeritus. Professor Kimura passed away on July 17, 2026, at the age of 88.
Professor Kimura joined the National Laboratory for High Energy Physics, the predecessor of KEK, as an associate professor when the laboratory was established in 1971. He played a key role in the design and construction of the KEK 12-GeV Proton Synchrotron (KEK-PS), contributing greatly to the project’s success.
He later took charge of accelerator research at KEK and led the design and construction of TRISTAN, an electron–positron collider that enabled experiments at what was then the world’s highest collision energy. In 1994, he became deputy directorof KEK. In this role, he made his effort forlaboratory management and promote major projects, including the B-factory project and neutrino oscillation experiments.
When the High Energy Accelerator Research Organization was established in 1997, Professor Kimura was appointed the first director of the Institute of Material Structure Science (IMSS). Under his leadership, IMSS pursued major upgrades to the Photon Factory, expanded its neutron and meson research facilities, and worked with the Japan Atomic Energy Research Institute—now the Japan Atomic Energy Agency—to develop the Japan Proton Accelerator Research Complex (J-PARC). His vision and leadership left a lasting mark not only on KEK’s research but also on the development of the organization as a whole.
Professor Kimura served in a number of important academic and advisory roles. These included membership of the Management Council of the National Laboratory for High Energy Physics, the Council for Science and Technology, the Management Councilof the Center for National University Finance, and the Management Council of the Graduate University for Advanced Studies (SOKENDAI). He also served as Dean of SOKENDAI’s School of Mathematical and Physical Science.
His research achievements were recognized with the Inoue Prize for Science and the Encouragement Prize by Foundation for High Energy Accelerator Science, as well as election as a Fellow of the American Physical Society. In 2016, he received the Order of the Sacred Treasure, Gold Rays with Neck Ribbon, in recognition of his distinguished contributions to education and research over many years.
KEK extends its deepest condolences to Professor Kimura’s family, friends, and colleagues. We remember with profound gratitude his exceptional service to KEK and his enduring contributions to scientific research in Japan.
