Paul Langevin

Biography

Paul Langevin was born on 23 January 1872 in Paris. Langevin graduated from ESPCI Paris in 1892 with a degree in Physics. He then studied at the École normale supérieure, where he passed the agrégation in 1897. The following year, he went to the University of Cambridge, where he studied under J. J. Thomson in the Cavendish Laboratory. In 1901, Langevin became a preparator in the Physics Teaching Laboratory at the University of Paris, where he received his Ph.D. the following year, supervised by Pierre Curie. His most famous work was in the use of ultrasound using Pierre Curie's piezoelectric effect. During World War I, he began working on the use of these sounds to detect submarines through echo location,

Personal life In 1898, he married Emma Jeanne Desfosses, and together they had four children, Jean, André, Madeleine and Hélène.

In 1910, he reportedly had an affair with the then-widowed Marie Curie; some decades later, their respective grandchildren, grandson and granddaughter Hélène Langevin-Joliot married one another. He was also noted for being an outspoken opponent of Nazism, and was removed from his post by the Vichy government following the occupation of the country by Nazi Germany. He was later restored to his position in 1944. He died in Paris in 1946, two years after living to see the Liberation of Paris. He is buried near several other prominent French scientists in the Panthéon in Paris.

In 1933, he had a son with physicist Eliane Montel (1898–1993), Paul-Gilbert Langevin, who became a renowned musicologist.

His daughter, Hélène Solomon-Langevin, was arrested for Resistance activity and survived several concentration camps. She was on the same convoy of female political prisoners as Marie-Claude Vaillant-Couturier and Charlotte Delbo.

Submarine detection In 1916 and 1917, Paul Langevin and Chilowsky filed two US patents disclosing the first ultrasonic submarine detector using an electrostatic method (singing condenser) for one patent and thin quartz crystals for the other. The amount of time taken by the signal to travel to the enemy submarine and echo back to the ship on which the device was mounted was used to calculate the distance under water.

In 1916, Lord Ernest Rutherford, working in the UK with his former McGill University PhD student Robert William Boyle, revealed that they were developing a quartz piezoelectric detector for submarine detection. Langevin's successful application of the use of piezoelectricity in the generation and detection of ultrasound waves was followed by further development.

Recognition Awards Year Organization Award Citation 1915 Royal Society Hughes Medal "For his important contributions to, and pre-eminent position in, electrical science." 1940 Royal Society Copley Medal "For his pioneer work on the electron theory of magnetism, his fundamental contributions to discharge of electricity in gases, and his important work in many branches of theoretical physics."

Memberships Year Organization Type 1928 Royal Society Foreign Member 1934 French Academy of Sciences Member