Toshiko Yuasa(1909 — 1980)

Toshiko Yuasa

Japon, empire du Japon

6 min read

SciencesScientifique20th CenturyThe first half and middle of the 20th century, marked by the rise of nuclear physics, the Second World War and the development of international scientific research.

Toshiko Yuasa (1909-1980) was the first female Japanese physicist. A specialist in radioactivity and nuclear physics, she spent the bulk of her career in France, at the CNRS, following in the footsteps of the Joliot-Curies' work.

Frequently asked questions

The key thing to remember is that Toshiko Yuasa (1909-1980) was Japan's first female physicist, a pioneer in a field that was then almost exclusively male. What makes her singular is that she carried out most of her career in France, at the CNRS, in the footsteps of the Joliot-Curies, specialists in radioactivity. Less well known than her contemporaries, she nonetheless made a decisive contribution to the study of the beta-ray spectrum, a key area of the nuclear physics of her time.

Key Facts

  • Born in 1909 in Tokyo, she was the first Japanese woman to become a physicist.
  • Arrived in Paris in 1940 to study radioactivity in the laboratory of Frédéric Joliot-Curie.
  • In 1944, during the liberation of Paris, she left the city by bicycle, taking her spectrometer with her.
  • Joined the CNRS in 1949, where she continued her research on beta decay.
  • Died in 1980 in Paris, after a scientific career conducted mostly in France.

Works & Achievements

Doctoral thesis on the spectrum of beta rays (1943)

Doctoral work defended in France, studying the shape of the continuous energy spectrum of beta rays, building on the research of the Joliot-Curies.

Construction of a beta-ray spectrometer (1940s)

Design and fabrication of her own measuring instrument, which she saved during her flight from Berlin and which symbolizes her experimental ingenuity.

Research on beta decay at the CNRS (1950s-1970s)

In-depth experimental studies on the shape of beta spectra and the physics of radioactive nuclei, carried out as a permanent researcher at the CNRS.

Scientific publications in nuclear physics (1940s-1970s)

Notes and articles published in French and international journals, contributing to the understanding of beta radioactivity.

Writings and essays on France (in Japanese) (1950s-1970s)

Texts in which Yuasa recounts her life as a scientist in Paris, introducing French culture to the Japanese public.

Anecdotes

In 1940, in the middle of the World War, Toshiko Yuasa crossed Eurasia alone by train on the Trans-Siberian Railway to reach Paris and join the laboratories of Frédéric and Irène Joliot-Curie. This journey of several weeks, from Japan to occupied France, reflects her determination to study radioactivity alongside the world's leading specialists.

At the end of the war, in 1945, Yuasa fled the bombing of Berlin, carrying with her own hands the beta-ray spectrometer she had built herself. According to the famous account, she transported her precious instrument by bicycle and on foot amid the chaos, refusing to abandon the tool of all her research.

Toshiko Yuasa was Japan's first woman physicist. During her studies at Tokyo's Bunrika University, she was the only female student in an entirely male class, at a time when science was almost exclusively reserved for men.

In 1944, at the Liberation of Paris, Yuasa had to leave France: as a national of an enemy country (Japan was allied with Germany), she was no longer allowed to continue her work. Rather than give up research, she left to carry on her experiments in Germany, in Berlin.

Today, a Franco-Japanese particle physics laboratory, the “Toshiko Yuasa Laboratory” (TYL), bears her name. It symbolizes the scientific bridge between France and Japan that she embodied all her life, having split her career between the two countries.

Primary Sources

On the Spectrum of Beta Rays (Comptes Rendus de l'Académie des Sciences) (1940s)
Note presenting her experimental measurements of the shape of the continuous spectrum of beta rays emitted by radioactive elements, carried out in the laboratory of Frédéric Joliot-Curie.
Doctoral thesis in physical sciences, University of Paris (1943)
Work devoted to the study of the continuous spectrum of beta rays, defended in France during the war in the wake of the Joliot-Curies' research on radioactivity.
Essays and Letters from France (written in Japanese) (1950s-1970s)
Accounts and correspondence in which Yuasa describes her life as a researcher in Paris, her attachment to France, and the material conditions of research in the postwar period.

Key Places

Tokyo, Japan

Toshiko Yuasa's birthplace, where she grew up and pursued her higher studies in physics at Bunrika University.

Collège de France, Paris

Frédéric Joliot-Curie's laboratory, where Yuasa carried out her first French research on radioactivity starting in 1940.

Berlin, Germany

The city where Yuasa continued her experiments after having to leave France in 1944, and which she fled in 1945 with her spectrometer.

CNRS, Paris region

The Centre National de la Recherche Scientifique, where Yuasa spent the bulk of her career from 1949 onward, rising to the rank of research director.

Paris, France

The city where Toshiko Yuasa spent most of her life as a researcher and where she died in 1980.

See also