Hull, Albert Wallace

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Hull, Albert Wallace

(b. Southington, Connecticut, 19 April 1880; d Schenectady, New York, 22 January 1966)

electron physics.

Hull was the second of nine sons of Lewis Caleb and Frances Reynolds Hinman Hull, five of whom chose technical careers after attending Yale University. His first bent was classical: he studied Greek at Yale and after graduation taught French and German at Albany Academy (where Joseph Henry had also taught) for one year. Recognizing an enthusiasm for physics, he returned to Yale for graduate work, obtained the doctorate in 1909, and taught for five years at Worcester Polytechinc Insitute in Massachusetts before his work came to the attention of Irving Langmuir and others at the General Electric Company.

Hull joined the famed General Electric Research Laboratory at Schenectady, New York, in 1914; his first work was on electron tubes, X-ray crystallography, and (during World War I) piezoelectricity. The work for which he is best known was done after the war, when he published the classic paper on the effect of a uniform magnetic field on the motion of electrons between coaxial cylinders. Versed in Greek, he coined the name “magnetron” for this configuration, which underlies the design of all subsequent “crossed-field” oscillators and amplifiers in which ultrahigh-frequency operation is achieved through control of the motion of electrons by oscillating electric and static magnetic fields at right angles to one another.

Hull’s other electron tube work in the 1920’s concerned noise measurements in diodes and triodes, the elimination of unwanted feedback in triodes through the introduction of a screen electrode (which marked his invention of the tetrode, independently of Walter Schottky, the acknowledged inventor), and the elimination of the destructive back bombardment of cathodes by residual gas ions, which he showed did no damage if their energy was kept below a certain value. The last project led to his invention of the thyratron, a heavy-duty, gas-filled electron tube originally intended for converting alternating current to direct current in high-power transmission; it found more immediate application in the electronic control of medium-power devices and thus led to the birth of a new branch of technology, industrial electronics.

In the 1930’s Hull’s interests broadened to metalurgy and glass science. Here again his researches had practical consequences, leading to the development of new alloys, such as Fernico, whose thermal and elastic properties matched those of glass sufficiently well to make strain-free glass-to-metal vacuum seals possible, a development of prime importance to the electrical industry.

Hull retired in 1950, after making additional contributions in World War II, but remained scientifically active to the end. His last publication, in 1966, came fifty-seven years after his first (a paper based on his 1909 doctoral dissertation), marking the end of an unusually long and fruitful career. He received many honors, including the Institute of Radio Engineers’ Liebmann Prize (1930) and Medal of Honor (1958), and election to the presidency of the American Physical Society (1942). He was a member of the National Academy of Sciences.

In 1911 Hull married Mary Shore Walker. They had two children: a daughter, Harriet, and a son, Robert Wallace Hull, also a physicist.

BIBLIOGRAPHY

Hull’s classic article on the magnetron is “The Effect of a Uniform Magnetic Field on the Motion of Electrons Between Coaxial Cylinders,” in Physical Review, 18 (1921), 31–57. A bibliography of his other publications follows the biography in Biographical Memoirs. National Academy of Sciences, 41 (1970), 215–233. Information about Hull’s forebears is contained in the history published by the Hull family, The Hull Family in America (Pittsfield, Mass., 1913), which traces his ancestry to the seventeenth century.

Charles SÜsskind