Andrew D Chew, January 2008

Saul Dushman was a prolific scientist with a wide range of interests who made major contributions to vacuum science. He was born in Rostov-on-Don (known as the ‘crossroads’ of the North Caucasus, Central Russia and the Ukraine) in Tsarist Russia in July, 1883. This was two years after the wide-scale anti-Jewish pogroms which swept southern Russia and in 1891, the year of mass Jewish expulsions, he emigrated with his family to the United States.
In 1900 he left public school in Toronto with the best ever Prince of Wales scholarship to study at the University of Toronto; a feat all the more remarkable since he arrived at school unable to speak English. Subsequently Dushman worked there in several roles after completing his first degree and in 1912 graduated with a PhD in physical chemistry. That year he joined the General Electric Research Laboratory. He stayed there all his career (apart from a sojourn as the Director of Research at the first GE lamp factory 1923-1925) and he eventually rose to assistant director, a post he held from 1928 to 1948.

His interests covered a wide spectrum: quantum mechanics, electromotive force, atomic structure, electron emission, unimolecular force as well as high vacuum. An example of an immediate application of his interests came with quantum theory applied to gas discharge light sources. In 1914 he produced a commercially viable 40 kV vacuum ‘Kenotron’ rectifier. This was a two-electrode valve employed as oscillation detectors for radio reception. In the same year he published two papers on a novel thermionic method to determine the electron’s charge to mass ratio.

Dushman worked closely with the Nobel-laureate Irving langmuir and focused on vacuum as subject as well as applying it. He developed a formula to calculate the conductance of (short) cylindrical tubes which is still in common usage today. Another contribution was in 1913 when Dushman, from an idea by Langmuir, developed a rotating disc (molecular) primary gauge for absolute, high vacuum measurement. This has specific relevance for the author who 80 years later, rebuilt the instrument as a direct primary gauge. The complexity involved in my development only reinforces the respect accorded to this past pioneer who had much more limited technology then to hand! He also wrote on the structure and calibration of ionization gauges over a time span of 24 years staring in 1921.

Dushman wrote many articles and text books of which several became standard texts. Based on lectures and internal GE articles Dushman published The Production and Measurement of High Vacuum in 1922. In 1949 he published the Scientific Foundations of Vacuum Technique (revised by Lafferty in 1961) which stills ranks, arguably, unequalled in the vacuum world: a testament to its clarity, comprehensiveness and accessibility. Other books were Quantum Theory and Atomic Structure (1931), Elements of Quantum Mechanics (1938) and The Fundamentals of Atomic Physics(1951).

Dushman retired at the end of 1948 and he died in 1954. The GE Dushman Award was inaugurated in 1977 to recognize outstanding scientific contributions within the company in memory of Dushman, a true hero of vacuum