Irène Joliot-Curie and Artificial Radioactivity

Irene and Marie Curie (1925)

On September 12, 1897, French Physicist and Nobel Laureate Irène Joliot-Curie was born. She was the daughter of Marie Skłodowska-Curie and Pierre Curie and the wife of Frédéric Joliot-Curie, with whom she jointly was awarded the Nobel Prize for Chemistry in 1935 for their discovery of artificial radioactivity.

In the Footsteps of Giants

Irène Curie was the elder daughter of Nobel Prize winners Marie and Pierre Curie.[3] When she was eight years old, her father died. She therefore grew up under the care of her grandfather Eugène Curie, who mainly influenced her political views. Her mother Marie Curie initially organized a learning cooperative together with fellow scientists, in which they taught their children themselves. Among other things, Marie Curie demonstrated physics experiments, and Paul Langevin taught mathematics. Later Irène attended the Collège Sévigné.

Academic Education

In her doctoral thesis at the Radium Institute in Paris, Irène Curie studied the alpha rays emitted by polonium, a radioactive element discovered by her mother Marie Curie in 1898. To do this, Irène Curie had to extract the polonium from crushed radon ampoules used in cancer therapy. She succeeded in precisely measuring the initial speed of the alpha particles, for which she used a device she had designed herself. She received her doctorate in 1925.

How Irène met Frederic

During World War I, Marie Curie organized a mobile X-ray service for the front. Initially, the then 17-year-old Irène helped as an assistant to her mother, but soon she was running her own X-ray station in the military hospital in Amiens. She also studied mathematics and physics at the University of Paris, graduating in 1920. After the war, she became an unpaid research assistant at her mother’s radium institute, later she was given a position as a sub-assistant. At the institute she also met a chemistry laboratory assistant named Frédéric Joliot, whom she was to instruct. The two married on October 9, 1926, and Frédéric took his high school diploma, which he had not been able to complete because of the war, completed his licentiate and received his doctorate in 1930. His first child, Hélène, was born in 1927 and his son Pierre in 1932. In 1935 Irene and Frédéric Joliot-Curie were jointly awarded the Nobel Prize in Chemistry.

Almost Discovering the Neutron

Since 1928 Irène and Frédéric Joliot-Curie had experimented together. In 1931, they repeated an experiment first performed by Walther Bothe and Herbert Becker: they irradiated thin layers of various materials with alpha particles from a strong polonium source. If these materials contained hydrogen, a new type of radiation was created, which the two of them interpreted as ejected hydrogen nuclei, i.e. protons – they had just missed the discovery of the neutron. The English physicist James Chadwick only succeeded in doing this when he repeated the experiments. He was awarded the Nobel Prize in Physics for this in 1935.[4] In 1932, the research couple observed positively charged electrons in a cloud chamber, but could not classify this result and interpreted it as an artifact. They did not know that the English physicist Paul Dirac [5] had already predicted the positron as an antiparticle of the negatively charged electron in 1931 – which says a lot about the relationship between theoreticians and experimental physicists at the time. In 1933, they revised the interpretation of their experiment, but by then the American Carl David Anderson had already beaten them to it.[6] In 1933, Irène and Frédéric Joliot-Curie discovered artificial radioactivity, for which they were awarded the Nobel Prize for Chemistry in 1935

Politics

Irène Joliot-Curie was strongly involved in politics. In 1934 she and her husband participated for the first time in an action committee of anti-fascist intellectuals. In spring 1936, the Popular Front under Léon Blum won the elections. The Nobel laureate joined the government as Secretary of State for Science and Research, making her one of the first group of three women ever appointed to the cabinet in France – at that time women in France did not even have the right to vote. Irène Joliot-Curie only stayed on the job for three months; she wanted to set an example for the women’s movement.

Teaching and the Resistance

In 1937 she was appointed to a lecturing post at the Sorbonne. After the occupation of Paris by German troops, the couple fled to Clermont-Ferrand in June 1940, but returned to the capital. In Paris, her husband played a risky double role as a researcher at the Collège de France and as a Resistance fighter. The Nobel Prize winner had already contracted tuberculosis in 1935; on June 6, 1944, she traveled with her children to Switzerland to have a new attack of tuberculosis treated.

The French Atomic Energy Commission

On October 18, 1945, the French Atomic Energy Commission (CEA) was founded, and Frédéric Joliot-Curie was appointed as its first High Commissioner. His wife became one of three commissioners. However, because she continued to be politically involved in organizations close to the Communists, her term of office was not renewed. Between 1951 and 1954, she applied four times for a seat in the Academy of Sciences to denounce the misogynist tradition of this institution. She was rejected each time.

Leukemia

Irène Joliot-Curie died of leukemia in 1956, probably as a result of her handling of large quantities of polonium and her work in the X-ray service during the First World War. The government ordered a state funeral.

MASTERCLASS | Les femmes et la science : Marie Curie, un modèle d’émancipation féminine [10]