Frédéric Joliot

Paris, 1900—Arcouest, France, 1958.

French physical chemist who discovered with his wife Irene artificially induced radioactivity by creating new radioisotopes. He studied at the Lakanal Lyceum, where he stood out more for his sports than academic activity. The setbacks in the family economy forced him to attend the free public school Lavoisier to prepare for admission to the School of Physics and Industrial Chemistry in Paris, where in 1923 he would obtain the title of engineer with the highest grade of his promotion.

After completing his military service, he accepted a research scholarship and, following Paul Langevin's recommendations, in 1925 he accepted a contract as an assistant at the Radium Institute under the direction of Marie Curie. Marie Curie's daughter, Irène, took it upon herself to teach her how to work with radioactivity. A year later Irène and Frédéric were married in a civil ceremony.

At the same time he continued studying for a degree in science and worked as a teacher at the Charliat School of Industrial Electricity, to improve his economic situation. He received a Bachelor of Science in 1927 and a Ph.D. in 1930 with a thesis on the electrochemical study of radioelements. From 1928 he signed jointly with his wife all the scientific works.Ambos llevaron a cabo notables trabajos de radiactividad y de física nuclear. En 1934 el matrimonio publicó una memoria mostrando la preparación de radioisótopos artificiales al bombardear átomos ligeros (boro, aluminio y magnesio). Observaron que en el proceso de bombardeo el átomo absorbía una partícula alfa a la vez que se producían protones y neutrones, e incluso positrones (la antipartícula del electrón). De esta manera obtuvieron isótopos radiactivos de elementos que no lo eran y revelaron la posibilidad de aplicar sus descubrimientos para conseguir cambios químicos en procesos fisiológicos. Sus suposiciones fueron verificadas posteriormente al detectarse la absorción de yodo radiactivo por parte de la glándula tiroides.

The Joliot-Curie experiments showed that the elements used as targets continued to emit positrons after the bombardment had ended, that is, they behaved like a radioactive substance. Over time it was found that any element that had one or more stable types of nuclei could also have radioactive nuclei, now known as radioisotopes. The discovery of the neutron in 1932 by Sir James Chadwick and the positron by Carl D. Anderson were also a consequence of the research carried out by the couple. Enrico Fermi's method using neutron bombardment, which led to the fission of uranium, is an extension of the Joliot-Curie procedure in which alpha particles were used to obtain artificial radioisotopes.

In 1935 the Joliot-Curie couple were awarded the Nobel Prize in Chemistry for the synthesis of new radioactive elements and were awarded the Bernard Medal of Columbia University in 1940. In 1937, Frédéric held a chair at the College of France. He prepared new radiation sources and supervised the construction of the Arcueil-Cachan and Ivry accelerators, and the cyclotron at the Collège de France (the second in Europe after that of the Soviet Union).