Jesse DuMond

Jesse William Monroe DuMond (born July 11, 1892 in Paris , † December 4, 1976 ) was an American experimental physicist.

DuMond was born in France as a US citizen. He studied at Caltech , where he made his bachelor's degree in 1916 (with the construction of a calculating machine, a "Harmonic Analyzer", for his master's thesis he built a calculating machine for complex numbers) and in 1929 received his doctorate in physics. In between he was from 1917 to 1918 at General Electric as an electrical engineer, briefly during the First World War when determining the distance of artillery via sound, 1919/1920 at the Thomson-Houston Company in Paris and 1920/21 at the National Bureau of Standards , where he worked with internal Ballistics was busy. The rest of his career he was at Caltech from 1929 (at the invitation of Robert Millikan ), from 1938 as an associate professor and from 1946 as a professor. In 1963 he retired.

He had been a member of the National Academy of Sciences since 1953 . In 1931 he became a Fellow of the American Physical Society .

DuMond became known for his investigation of line broadening in the Compton effect due to the speed distribution of electrons in the atom, carried out in his dissertation. To this end, he developed a new type of X-ray spectrometer with several crystals and also had the original idea for X-ray spectrometers with curved crystal surfaces. He mostly built his measuring equipment himself and showed great mechanical skill. Later he dealt with the precise determination of fundamental physical constants, such as Planck's constant and the electron charge. He found a discrepancy in the value of the electron charge between the value that Millikan had measured with his oil droplet experiment and the value from X-ray diffraction experiments. Millikan then checked his old experiment and corrected its result (the parameter was the viscosity of the air, which Millikan had a student re-determine). With E. Richard Cohen he published regular review reports on the status of the determination of the fundamental physical constants. DuMond also developed a gamma-ray spectrometer, which, however, was only finished after the Second World War and with which he then operated nuclear spectroscopy.

During the Second World War he dealt with rocket technology, the construction of an aerial camera and the demagnetization of ships as a measure against magnetic mines.

DuMond was married twice and had three children from his first marriage. One daughter was married to Wolfgang Panofsky .

literature

• DuMond The Autobiography of a Physicist , 2 volumes, 1972
• Wolfgang Panofsky: Jesse DuMond, in Biographical Memoirs of the National Academy of Sciences.

Web links

• Biography at the APS
• Literature by and about Jesse DuMond in the WorldCat bibliographic database