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Iren Joliot-CurieChemist, Nobel Prize laureate in Chemistry
Date of Birth: 12.09.1897
Country:  France |
Content:
- Irene Joliot-Curie: The Legacy of a Nobel Prize-Winning Chemist
- Education and Early Influences
- Nuclear Research and the Discovery of Artificial Radioactivity
- The Discovery of Artificial Elements and the Nobel Prize
- Political Activism and the War Years
Irene Joliot-Curie: The Legacy of a Nobel Prize-Winning Chemist
A Daughter of ScienceIrène Joliot-Curie was born in Paris on September 12, 1897, the eldest of two daughters of Pierre Curie and Marie (Skłodowska) Curie. Marie Curie had discovered radium just a year before Irène's birth. Around the same time, Irène's paternal grandfather, Eugène Curie, moved in with the family. Eugène Curie, a doctor by profession, had volunteered his services to the revolutionaries during the 1848 uprising and had worked with the Paris Commune in 1871. Eugène Curie became Irène's constant companion while her mother was preoccupied with her laboratory work. His liberal socialist beliefs and anticlericalism profoundly influenced Irène's developing political views.
Education and Early Influences
At age 10, a year before her father's death, Irène Joliot began attending the cooperative school organized by her mother and several of her colleagues, including physicists Paul Langevin and Jean Perrin, both of whom also taught at the school. She later enrolled at the Sévigné College, which she completed just before the outbreak of the First World War. Irène Joliot continued her education at the Sorbonne, but interrupted her studies for several months to serve as a volunteer nurse in a military hospital, helping her mother with X-rays.
After the war, Irène Joliot became a research assistant at the Curie Institute, headed by her mother, and in 1921, she embarked on her own research. Her early experiments focused on the radioactive element polonium, an element discovered by her parents over two decades earlier.
Nuclear Research and the Discovery of Artificial Radioactivity
As the phenomenon of radioactivity was linked to the disintegration of atoms, studying it held the promise of shedding light on the structure of the atom. Irène Joliot examined the fluctuations observed in the range of alpha particles, which are typically emitted with extraordinarily high velocity during the decay of polonium atoms. Alpha particles, composed of two protons and two neutrons and thus helium nuclei, had first been identified as a tool for studying atomic structure by English physicist Ernest Rutherford. In 1925, Irène Joliot's doctoral thesis was awarded for her investigations into these particles.
Her most significant research began several years later, after she married her colleague, fellow Curie Institute assistant Frédéric Joliot, in 1926. In 1930, German physicist Walter Bothe discovered that certain light elements (including beryllium and boron) emitted powerful radiation when bombarded with alpha particles. Intrigued by the questions their discovery raised, the Joliot-Curies (as they became known) set up an unusually strong polonium source to generate alpha particles and used a sensitive cloud chamber designed by Joliot to detect the penetrative radiation produced in this way.
They found that when a sheet of hydrogen-containing material was placed between the beryllium or boron and the detector, the intensity of the radiation observed nearly doubled. The Joliot-Curies attributed this effect to the penetrative radiation knocking off individual hydrogen atoms, giving them enormous velocity. Although neither Irène nor Frédéric understood the mechanism behind this process, their careful measurements paved the way for the 1932 discovery by James Chadwick of the neutron, an electrically neutral constituent of most atomic nuclei.
The Discovery of Artificial Elements and the Nobel Prize
Continuing their investigations, the Joliot-Curies made their most significant discovery. By bombarding boron and aluminum with alpha particles, they studied the production of positrons (positively charged particles otherwise identical to negatively charged electrons), first discovered in 1932 by American physicist Carl D. Anderson. Blocking the aperture of their detector with a thin sheet of aluminum foil, they exposed aluminum and boron samples to alpha particles. To their astonishment, they observed that positron emission continued for several minutes after the alpha-particle source from polonium had been removed.
The Joliot-Curies eventually concluded that some of the aluminum and boron in their samples had been transformed into new chemical elements. Moreover, these new elements were radioactive: having absorbed two protons and two neutrons from the alpha particles, aluminum had become a radioactive isotope of phosphorus, while boron had become a radioactive isotope of nitrogen. Within a short time, the Joliot-Curies produced many new radioactive elements.
In 1935, Irène Joliot-Curie and Frédéric Joliot were jointly awarded the Nobel Prize in Chemistry "for their synthesis of new radioactive elements." In his presentation speech on behalf of the Royal Swedish Academy of Sciences, K.W. Palmearer reminded Joliot-Curie of how, 24 years earlier, she had been present at a similar ceremony when her mother received the Nobel Prize in Chemistry. "In collaboration with your husband," Palmearer said, "you have worthily continued this brilliant tradition."
A year after receiving the Nobel Prize, Joliot-Curie became a full professor at the Sorbonne, where she had been lecturing since 1932. She also maintained her position at the Curie Institute and continued her research on radioactivity. In the late 1930s, Joliot-Curie made several important discoveries working with uranium, coming tantalizingly close to discovering that neutron bombardment could split (fission) the uranium atom. Pursuing the same line of experiments, German physicist Otto Hahn and his colleagues Fritz Strassmann and Lise Meitner achieved uranium fission in 1938.
Political Activism and the War Years
Meanwhile, Joliot-Curie had become increasingly active politically, serving in 1936 for four months as Undersecretary of State of Scientific Research in the government of Léon Blum. Despite the German occupation of France in 1940, Joliot-Curie and her husband remained in Paris, where Joliot became involved with the Resistance. When suspicion of his activities mounted in 1944, and he went into hiding that autumn, Joliot-Curie and their two children fled to Switzerland, where they remained until the liberation of France.
In 1946, Joliot-Curie was appointed the Director of the Curie Institute. She also served from 1946 to 1950 on the French Commissariat for Atomic Energy. Deeply concerned throughout her life with issues of women's social and intellectual advancement, she was on the National Committee of the Union of French Women and worked with the World Peace Council. By the early 1950s, her health was beginning to deteriorate, presumably from the cumulative effects of radiation exposure. Joliot-Curie died in Paris on March 17, 1956, from acute leukemia.
A tall, slender woman known for her patience and even temperament, Joliot-Curie was an accomplished swimmer, skier, and hiker. In addition to the Nobel Prize, she received honorary degrees from many universities and was a member of numerous scientific societies. She was awarded the Barnard Gold Medal for Meritorious Service to Science from Columbia University in 1940 and was a Chevalier of the French Legion of Honor.
