ALLISON, SAMUEL KING

(b. Chicago, Illinois, 13 November 1900; d. Oxford, England, 15 September 1965)

physics.

Samuel K. Allison, the son of Samuel Buell Allison, an elementary school principal, and Caroline King Allison, attended elementary school and Hyde Park High School in Chicago. In 1917 he entered the University of Chicago. Doing honors work in chemistry and mathematics and studying physics under R. A. Millikan, he received his B.S. degree in 1921. Two years later he earned his Ph.D. degree in chemistry (with a thesis on a problem in experimental physics) under William D. Harkins. He married Helen Catherine Campbell on 28 May 1928, and they had two children, Samuel and Catherine.

Allison then received a National Research Council Fellowship to pursue postdoctoral research in William Duanc’s laboratory at Harvard University. He arrived there in the fall of 1923, just as G. L. Clark, another National Research Council Fellow, and Duane challenged the validity of the Compton effect, discovered by Arthur H. Compton at Washington University in St. Louis in late 1922. Duane and Compton (who transferred to the University of Chicago in mid 1923) debated the issue vigorously at a meeting of the American Physical Society in December 1923 and during an exchange of visits to each others’ laboratories in early 1924. Allison was drawn into the dispute, and his initial experiments seemed to support Clark and Duane’s position. Only after Compton and Duane engaged in a second debate at a meeting of the British Association for the Advancement of Science in Toronto in the summer of 1924 did Allison find persuasive evidence for the validity of the Compton effect, which compelled Duane to withdraw his objections at the December 1924 meeting of the American Physical Society.

Allison left Harvard in mid 1925 for a third year of postdoctoral research at the Carnegie Institution in Washington, D.C., after which Leonard B. Loeb was instrumental in bringing him to the University of California in Berkeley. He remained in the Berkeley physics department four years, until mid 1930, rising from the rank of instructor to associate professor. Continuing his X-ray researches, soon with the help of his graduate student, John H. Williams, Allison designed and constructed a new highresolution double-crystal X-ray spectrometer, used it to measure precisely the intensities and widths of various X-ray lines, and in this way confirmed the dynamical theory of X-ray diffraction that had been developed independently by C. G. Darwin in 1914 and by P. P. Ewald in 1917. This collaboration cemented a lifelong friendship between Allison and Williams. When Arthur Compton persuaded Allison to return to Chicago in 1930, Williams followed as a National Research Council Fellow from 1931 to 1933 and then joined the faculty of the University of Minnesota. In subsequent years, the two spent several weeks together each summer on fishing and canoe trips in Wisconsin and Canada.

Allison remained on the faculty of the University of Chicago for the rest of his life. Until 1935 his research continued in the field of X rays; it culminated in the publication of his and Compton’s authoritative treatise, X-Rays in Theory and Experiment (1935), a work which, as Compton acknowledged in the preface, Allison was primarily responsible for writing. After its completion, Allison redirected his research into the growing field of experimental nuclear physics. He spent six months in Rutherford’s Cavendish Laboratory in Cambridge. England, learning techniques and working with Cockcroft and Walton’s accelerator. On his return, he built a machine of this type, thereby introducing experimental nuclear research into the University of Chicago’s physics department. He and his students used it to make precision measurements of the masses of various light isotopes by means of proton-induced reactions.

Allison’s experience in experimental nuclear research placed him in a position to play a key role in the Manhattan Project. In January 1941 he obtained a contract from the National Defense Research Committee to study the feasibility of using beryllium as a neutron reflector and as a moderator in a pile. Thus, when Compton organized the Metallurgical Laboratory a year later in February 1942, bringing Enrico Fermi’s Columbia team and Eugene Wigner’s Princeton team to Chicago, Allison already had an active and knowledgeable group working there. He was promoted to full professor, appointed head of the chemistry division, and joined Fermi and others in the construction of the first pile under the West Stands of Stagg Field. When it achieved criticality on 2 December 1942, Allison was in charge of the “suicide squad” that was to dump a huge jug of cadmium solution over the pile to quench the chain reaction in the remote possibility of an uncontrolled runaway.

The principal mission of the Metallurgical Project. with plants at Chicago, Oak Ridge, Tennessee, and Hanford, Washington, was to develop methods for the large-scale production of plutonium. As Compton’s responsibilities as overall director grew, he decided to appoint Allison, in 1943, director of the “Met Lab” in Chicago. Allison’s deep scientific and technical knowledge, his singleness of purpose and exceptional administrative abilities, and his personal patience, sound common sense, and dry sense of humor made him a natural and logical choice for this position. As director he had to solve a host of problems of all kinds, and he had to work fruitfully with people of many backgrounds, including engineers and executives from the Du Pout Company, whom he assisted in the design and construction of the reactors at Hanford.

In November 1944 Allison transferred to Los Alamos, where he served as Robert Oppenheimer’s associate director and as chairman of the Technical and Scheduling Committee, which in early 1945 became the nerve center for coordinating experiments, facilities, and materials for the construction of the atomic bomb. He also became a key member of the “Cowpuncher Committee” charged to “ride herd” on the development of the implosion method of detonation. It was Allison who called the countdown of the Trinity test of the plutonium bomb in the early morning hours of Monday, 16 July 1945.

Three weeks after the war ended, on I September 1945, Allison sounded another call. Some sixteen scientists, including Fermi and Harold C. Urey, joined Allison at a news conference in the Shoreland Hotel on the South Side of Chicago to announce their affiliation with the newly established Institute for Nuclear Studies of the University of Chicago. Allison, as its director-designate, used this occasion to make an eloquent plea for the return of tree and unhampered research. He remarked. bluntly, that if secrecy was imposed, all first-rate scientists would work on subjects as innocuous as the colors of butterflies’ wings. “Sam’s butterfly speech” became a clarion cry for civilian control of nuclear research after the war. Allison became a founding sponsor of the Bulletin of the Atomie Scientists, and he continued to courageously argue the case against secrecy in government-supported research even after the shocking arrest of Alan Nunn May in early 1946 and of Klaus Fuchs in early 1950 as Soviet spies.

In 1946 Allison received the Medal of Merit for his wartime contributions, with a special citation from President Truman, and he was also elected to the National Academy of Sciences. As director of Chicago’s Institute for Nuclear Studies (later renamed after Enrico Fermi), he assembled a distinguished group of physicists, chemists, and astrophysicists, and he fostered a spirit of scientific collaboration among them. He also personally carried out and supervised a good deal of research in experimental low-energy nuclear physics using a new 400-keV Cockcroft-Walton accelerator that he constructed in 1949. A number of his students from these years, as from earlier and later ones, became distinguished scientists in their own right.

In 1958 Allison resigned as director of the Enrico Fermi Institute to be able to devote more time to his research. The following year he was named Frank P. Hixon Distinguished Service Professor. In 1960 he traveled to Egypt, and in 1961 to Argentina, to serve as an adviser to those scientifically developing countries. In 1963 he completed the construction of a new 4-MeV Van de Graaff accelerator and again agreed to become director of the Enrico Fermi Institute. Two years later, on 6 September 1965, while serving as the United States delegate to the Plasma Physics and Controlled Nuclear Fusion Research Conference in Culham, England, he suffered an aortic aneurism and died following surgery at the Radcliffe Infirmary in nearby Oxford.

BIBLIOGRAPHY

I. Origin Works. Allison’s papers are preserved in the University of Chicago Library. His doctoral thesis was published as “The Absence of Helium from the Gases Left after the Passage of Electrical Discharges: I, Between Fine Wires in a Vacuum; II, Through Hydrogen; and III. Through Mercury Vapor,” in Journal of the American Chemical Society, 46 , no. 4 (1924), 814–824. written with W. D. Harkins. Some representative later publications are;’ Experiments on the Wave-lengths of Scattered X-Rays,”in Physical Review, 2nd ser., 26 , no. 3 (1925), 300–309, written with W. Duane; “The Resolving Power of Calcite for X-Rays and the Natural Widths of the Molybdenum Kα Doublet,” ibid., 2nd ser., 35 , no. 12 (1930), 1476–1490. written with J. H. Williams; “The Masses of Li⁶. Li⁷. Be⁸, Be⁹, and Be¹⁰ and B¹¹,” ibid., 2nd ser., 55 , no. 7 (1939), 624–627; “Passage of Heavy Particles Through Matter,” in Reviews of Modem Physics, 25 , no. 4 (1953), 779–817, written with S. D. Warshaw; and “Experiments on Charge-Changing Collisions of Lithium Ionic and Atomic Beams,” in Physical Review, 2nd ser., 120 , no. 4 (1960), 1266–1278, written with J. Cuevas and M. Garciu-Munoz.

II. Secondary Literature. Insightful obituary notices of Allison were written by Alvin Weinberg in the Bulletin of the Atomic Scientists, 22 , no. 1 (1966), 2, and by H. L. Anderson in Nature, 209 (19 February 1966), 758–759. Later biographical accounts were prepared by the University of Chicago (undated pamphlet on the Frank P. Hixon Distinguished Service Professorship, 32 pp.), and by R. S. Shankland, Dictionary of American Biography, Supplement Seven 1961–1965 (New York, 1981), 10–11.

For Allisons role in the Compton-Duane controversy, see Roger H. Stuewer, The Compton Effect: Turning Point in Physics (New York, 1975), 249–273. For information on Allisons role in the Manhattan Project and during the postwar period, see Richard G. Hewlett and Oscar E. Anderson, Jr., A History of the United States Atomic Energy Commission, 1 , The New World, 1939–1946 (University Park, Penn., 1962); Daniel J. Kevles, The Physicists: The History of a Scientific Community in Modern America (New York, 1978): Alice Kimball Smith. A Peril and a Hope: The Scientists’ Movement in America: 1945–1947 (Chicago, 1965); Henry De Wolf Smyth, Atomic Energy for Military Purposes: The Official Report on the Development of the Atomic Bomb Under the Auspices of the United States Government, 1940–1945 (Princeton, 1945).

Roger H. Stuewer