Yoshio Nishina – Father of Modern
Physics in Japan

Biography

Dr. Yoshio Nishina was born on 6 December 1890 in Hamanaka, Shinjo-Mura, Asaguchi-Gun, Okayama Prefecture (present-day Satosho-Cho), into a family of village headmen for many generations. He was recognized by all as a studious boy combined with artistic talent. After graduation from the 6th High School located in Okayama, he entered the Department of Electrical Engineering at the Imperial University of Tokyo, where he mastered state-of-the-art electrical engineering and graduated at the top of his class (see graduation thesis: Effects of Unbalanced Single-Phase Loads on Poly-Phase Machinery & Phase Balancing). The engineering background he acquired here provided the basis for his construction of large-scale experimental equipment in his later carrier.

While a student at the University of Tokyo, he listened to a lecture by Professor Hantaro Nagaoka, who proposed the world’s first “atomic model”, and became fascinated by “fundamental physics”, aiming to “investigate the world of atoms”, which was still in its infancy, and joined the RIKEN Foundation in 1920. RIKEN had just been established in 1917 as Japan’s first research institute for “pure science and its applications.”

After joining the institute, he studied at the Cavendish Laboratory in the UK, directed by Ernest Rutherford, who discovered the “nucleus” of the atom, in 1921 on the advice of Hantaro Nagaoka, a senior research fellow (also a professor at the University of Tokyo). There, he had a fateful encounter with Niels Bohr, who proposed a model of the atom based on a completely new “principle.” Bohr’s laboratory in Copenhagen, Denmark, was the center of the birth of “quantum mechanics”, and he moved there at Bohr’s invitation, where he studied from 1923 to 1928 amongst the world’s young geniuses, achieving outstanding experimental results in X-ray spectroscopy.

In 1928, his talents as a theorist blossomed and, together with his close friend the theorist Oskar Klein, he derived the “Klein-Nishina formula” for the scattering of X-rays by electrons, based on the newly published “relativistic quantum mechanics” of Paul Dirac, which earned him international recognition as an atomic physicist.

During his seven years of study in Europe, he honed his language skills as an international person and acquired the “Copenhagen Spirit”, a spirit of collaboration to tackle unsolved problems through free and open discussion, regardless of race or affiliation, which he brought back to RIKEN.

After returning to Japan, he ran the “Nishina Laboratory” at RIKEN from 1931, traveled to major universities to lecture on the new essence of atomic physics, and raised funds to invite Werner Heisenberg and Dirac to hear the young genius in person. He also invited George Hevesy, his mentor who pioneered the tracer technique for radioisotopes. In 1937, the long-sought invitation of Bohr was also realized.

Attracted by these lectures, the best and brightest gathered one after another in the “Nishina Laboratory”, which became one of the largest laboratories in RIKEN. In this way, he devoted himself to fostering world-class researchers in Japan who explored elementary particles, cosmic rays, atomic nuclei, and radioactive elements. The development of particle theory, including Dr. Hideki Yukawa’s Meson Theory and Dr. Shin-itiro Tomonaga’s Quantum Electrodynamics, for which they were later awarded Japan’s first and second Nobel Prize in Physics, the development of nuclear and cosmic ray research through the construction of large, costly experimental facilities, and the development of applications of radioactive isotopes in medicine and biology are largely owed by the guidance and encouragement of Dr. Nishina. Dr. Nishina constructed the Cyclotron, the world’s largest artificial element conversion device at the time, but it was destroyed by the Occupation Forces in November 1945 on the mistaken belief that it was used for the development of the atomic bomb.

On 8 August 1945, immediately after the atomic bombing of Hiroshima, he entered Hiroshima at the request of the Japanese Imperial Army to ascertain whether it was an atomic bomb or not. Based on scientific evidence unique to Dr. Nishina, such as the sensitivity of X-ray film and the radiolysis of human bones, he concluded that it was an atomic bomb, and this provided a major impetus for the end of the war in Japan. Dr. Nishina recalled the devastation of Hiroshima as “like a living hell”. After Hiroshima, he surveyed Nagasaki and returned to Tokyo. For a man who was researching the biological effects of radiation, it must have been a “life-threatening situation.”

In 1948, to somehow keep RIKEN alive after it was regarded as a zaibatsu by the Occupation Forces and dissolved, he transformed RIKEN Foundation into a private company called the Institute of Scientific Research (Kagaku Kenkyusho), and as its first president, he struggled to rebuild science and technology in Japan. He, unfortunately, fell ill halfway through and passed away on 10 January 1951 from liver cancer. His last words were “Work, work, work, and fall ill at autumn’s end”.

He was awarded the Order of Culture in 1946, became a member of the Japan Academy in 1948, and from 1949 was the first Vice-President of the Science Council of Japan, leading the scientific community in Japan.

His last will was “No War”, which he passed on to many of his students as Abolition of Nuclear Weapons. On the other hand, Dr. Nishina was also one of the first to appeal for the use of “nuclear” energy as a source of power in Japan, where energy resources are scarce.

The great work of Dr. Yoshio Nishina

Dr. Yoshio Nishina was the founder of Japan’s “particle theory”, “cosmic ray physics”, “elemental transformation”, “research on biological and medical applications of radioisotopes”, and “construction of large state-of-the-art experimental apparatus such as a Wilson cloud chamber and cyclotron. These were passed on to his successors and led to the Nobel Prize in Physics for particle theory by Professors Hideki Yukawa, Shin-itiro Tomonaga, Yoichiro Nambu, Makoto Kobayashi, and Toshihide Masukawa, and the Nobel Prize in Physics for neutrino observations by Professors Masatoshi Koshiba and Takaaki Kajita. Japan now boasts the world’s most powerful large-scale cosmic-ray observatory and accelerator facilities, for which Dr. Nishina laid the foundation.