Aston, Francis William (1877-1945), physicist

Francis William Aston was born at Harborne, near Birmingham on 1 September 1877. He attended Mason College (later the University of Birmingham) where he studied chemistry under P. F. Frankland. He left school and worked as a chemist at a brewery for three years, while pursuing an interest in physics, which attracted the attention of J. H. Poynting, professor of physics at the University of Birmingham, and became his research student. In 1908 he detected the phenomenon of a new 'primary cathode dark space'.

In 1909 he became a lecturer in physics at Birmingham, but moved on quickly, accepting an invitation from Sir J. J. Thomson to work, as his assistant, on positive rays at the Cavendish Laboratory, Cambridge. He became a member of Trinity College, Cambridge, took a B.A. degree by research in 1912 and was elected Clerk Maxwell scholar in 1913. It was during this period that he obtained definite evidence for the existence of two isotopes of the inert gas neon. Aston's research was interrupted by the first World War, when he worked at the Royal Aircraft Establishment, and in 1919 he returned to the Cavendish Laboratory to research the separation of the isotopes of neon. This was accomplished using his invention, the mass spectrograph, an apparatus which enabled him to identify isotopes of elements. He extended this technique to other chemical elements, discovering, in a series of measurements, 212 of the naturally occurring isotopes. From this work he formulated the whole number rule. In 1920 Aston was elected to the Fellowship of Trinity College Cambridge, was elected to the Royal Society in 1921 (winning the Hughes Medal in 1922 and giving the Bakerian Lecture in 1927), and in 1922 he was awarded the Nobel Prize for chemistry 'for his discovery, by means of his mass spectrograph, of isotopes, in a large number of non-radioactive elements, and for his enunciation of the whole number rule'.

Aston's book 'Isotopes' was published in 1922, with a second edition published in 1924. In 1933, he published a revised version with a narrower focus, 'Mass-spectra and Isotopes', with a second edition in 1942.

Aston's interests in astronomy and photography led to his membership of expeditions that studied eclipses in Sumatra (1925), Canada (1932) and Japan (1936). He served as President of the International Union of Chemistry's Commission on Atoms, 1935-1945. He continued to live and work in Cambridge, where he died on 20 November 1945.

Oxford Dictionary of National Biography