May 26, 2023  We held an IER Special Seminar. ＜by Prof. Emeritus HOSHI＞

　In some of the classes of the Master’s Program of Major in Environmental Radioactivity, distinguished external researchers are invited as guest lecturers, and their classes are open to other faculty members on campus as “Special Seminars”.

　On May 26, Professor Emeritus HOSHI Masaharu from Hiroshima University gave an online lecture on the class subject “Nuclear Disaster Study”. The lecture was attended by 26 IER graduate students majoring in Environmental Radioactivity and IER members. In his lecture, Prof. HOSHI explained his work on the development of the Dosimetry System (DS02) in Hiroshima and Nagasaki, as well as the results of dosimetry and epidemiological studies in Semipalatinsk, Kazakhstan. In view of the results of these studies, he explained the results of research on radioactive microparticles. Among victims of nuclear disasters such as the Semipalatinsk nuclear test and the atomic bombing of Hiroshima, it has been reported that some victims suffer from aftereffects such as severe fatigue that cannot be explained solely by radiation dose. A possible cause of these symptoms, he said, is that neutrons irradiated by the atomic bombs radiated geological materials, etc., resulting in the formation of radioactive microparticles. In particular, Mn-56 is considered to be the main causative nuclide, and a wide range of collaborative research to evaluate its effects and research outcomes were described.

　During the Q&A session, attendees asked particularly about the radioactive microparticles, followed by discussions about comparisons thereof with the radioactive cesium-rich microparticles (CsMP) in Fukushima and the hot particles in Chornobyl.