Owen Willans Richardson
The Nobel Prize in Physics 1928
Thermionic effects similar to those studied by Langmuir and Kingdon for caesium have been found for rubidium and potassium. Because of the difference in the electron affinity of tungsten (4.53 volts) and that of an atom of rubidium or potassium (4.16 and 4.32 volts respectively) positive ions are formed which at filament temperatures above 1000° are drawn to the cylindrical collector from the coaxial filament. Below this temperature the ions are adsorbed on the surface of the filament and decrease its work function raising the electron emission. The degree of thermal ionization at various filament temperatures is found to be within the experimental error of that determined from Saha's equation. At low temperatures the filament is partially covered by adsorbed ions and the electron emission increases exponentially with the reciprocal of the temperature. A transition region is reached as the average life of an atom on the surface becomes shorter and then the emission decreases logarithmically with the reciprocal of the temperature. The curves and values are given. The positive ion emission increases logarithmically with the reciprocal of the temperature until a certain fraction of the atoms striking the filament is ionized. Further increase in temperature causes every atom to be ionized. The coincidence of experimentally determined points with the theoretical space charge curve shows each ion to have the mass of a single atom in the range of pressures studied.
Thermionic phenomena, Richardson's Law
Owen Willans Richardson was born on the 26th of April, 1879, at Dewsbury, Yorkshire, England, as the only son of Joshua Henry and Charlotte Maria Richardson.
Educated at Batley Grammar School, he proceeded to Cambridge in 1897, having obtained an Entrance Major Scholarship at Trinity College; he gained First Class Honours in Natural Science at the examinations of the Universities of Cambridge and London, with particular distinctions in Physics and Chemistry. After graduating at Cambridge in 1900, he began to investigate the emission of electricity from hot bodies at the Cavendish Laboratory. In 1902 he was elected a Fellow of Trinity College, Cambridge. The law for the discovery of which the Nobel Prize was specially given, was first announced by him in a paper read before the Cambridge Philosophical Society on the 25th November, 1901, in the following words, as recorded in the published Proceedings: "If then the negative radiation is due to the corpuscles coming out of the metal, the saturation current s should obey the law s = AT1/2e-b/T. This law is fully confirmed by the experiments to be described." Richardson continued working at this subject at Cambridge until 1906, when he was appointed Professor of Physics at Princeton University in America, where he remained until the end of 1913, working at thermionic emission, photoelectric action, and the gyromagnetic effect. In 1911 he was elected a member of the American Philosophical Society, and in 1913 a Fellow of the Royal Society, whereupon (1914) he returned to England as Wheatstone Professor of Physics at King's College in the University of London. Among his publications were: The Electron Theory of Matter, 1914 (2nd ed., 1916), The Emission of Electricity from Hot Bodies, 1916 (2nd ed., 1921), Molecular Hydrogen and its Spectrum, 1934.
He was awarded the Hughes Medal by the Royal Society (1920), especially for work on thermionics; elected President, Section A, of the British Association (1921) and President of the Physical Society, London (1926-1928); appointed Yarrow Research Professor of the Royal Society, London (1926-1944), and knighted in 1939. Since 1914 he worked at thermionics, photoelectric effects, magnetism, the emission of electrons by chemical action, the theory of electrons, the quantum theory, the spectrum of molecular hydrogen, soft X-rays, the fine structure of Ha and Da. His last paper, with E. W. Foster, appeared in 1953. He received honorary degrees from the Universities of St. Andrews, Leeds, and London.
In 1906 he married Lilian Maud Wilson, the only sister of the well-known physicist H. A. Wilson, who was a fellow-student with him in Cambridge. There were two sons and one daughter of this marriage. After the death of his wife in 1945, Richardson married the physicist Henriette Rupp in 1948; he himself died in 1959.
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