He was born on June 4, 1932, in Tokyo, Japan, and received a Bachelor's degree (1955)from Okayama University and a Master's degree (1961) from Illinois University. He was affiliated with a large number of universities and research institutes. He was a Research Associate (1961) and an Associated Professor (1969) of Hiroshima University, an Associated Professor of Osaka University (1971), a Professor of Hokkaido University (1982), a Professor of Nagoya University (1987) and a Professor of Hiroshima Institute of Technology (1996). He was also a visiting researcher of Rutgers University (1968-1969), Max-Planck-Institute, Stuttgart (1978-1979) and Kyoto University (1993-1994).
Professor Kiritani started the research of irradiation damage using a high-voltage electron microscope at Osaka University. The main research subjects were on the interaction of high energy electrons with atoms in crystal, including the relationship between the state of electrons passing through the crystal with damage production, the replacement collision sequence, the electron irradiation induced diffusion of point defects and the measurement of the mobility of point defects from the dynamic behavior of visible point defect clusters.
During his stay at Hokkaido University, he devoted his time to the research of fusion neutron irradiation. He served as the chief investigator of the damage of solid materials in Japan-US Collaboration Program utilizing an intense fusion neutron source, RTNS-II, at Lawrence Livermore National Laboratory. Even now the systematic data he obtained with his collaborators are unique and have not been replaced. The results led to information about the structure of large collision cascades including their subdivision to subcascades, recoil energy spectrum analysis, which leads to the estimation of the energy deposition density. The detection of the role of freely migrating point defects and the point defect reaction by the effect of collision impact should also be mentioned.
After a systematic fusion neutron irradiation with careful controls, he became aware of the deficiency in almost all the fission reactor neutron irradiation experiments. At Nagoya University, he made his strongest effort to persuade the related scientists and reactor engineers of the necessity for temperature control, which is not affected by the reactor power. He succeeded in installing irradiation rig in Japan Materials Testing Reactor in JAERI, and proved that almost all the old data should be replaced. Because of his efforts, the direct comparison of fusion neutron irradiation with fission neutron irradiation became possible. Since then, irradiation with temperature control, not influenced by reactor environment, became the norm.
His loss will leave a deep voids in our hearts and we will miss him a lot. Please send regrets to: ToshimasaYoshiie (yoshiie@rri.kyoto-u.ac.jp)