Yoshio Nishina

Born on 6 December 1890 in a village near Okayama, Yoshio Nishina is considered the pioneer of Japanese nuclear physics. Nishina studied electrical engineering at Tokyo Imperial University, earning his degree in 1918. After entering the university’s graduate school, he switched to physics and became a research assistant at Japan’s RIKEN research institute. From 1921 to 1928, Nishina studied in Europe, where he worked in several laboratories, including in Copenhagen with Niels Bohr. In 1928 Nishina made one of his most important contributions to the field of quantum mechanics when he worked with Swedish physicist Oskar Klein on the Klein–Nishina formula for the scattering cross section of a photon. In the 1930s Nishina focused his research on cosmic rays and particle accelerator development. He started his own laboratory at RIKEN, where in 1937 he constructed a small cyclotron—only the second one ever built in the world. He soon added a second, larger one. During World War II, Nishina was recruited by the Imperial Japanese Army to investigate nuclear fission and the development of an atomic bomb. When the war ended, Japan’s cyclotrons were destroyed by US occupation forces. Nishina became RIKEN’s director and helped rebuild Japan’s science program. In 1946 he was awarded the Order of Culture by the Japanese government. Nishina died of liver cancer in 1951.

Date in History: 6 December 1890