Robert Fox Bacher, widely known for his leadership at the Radiation Laboratory at MIT and the experimental physics and bomb physics divisions at Los Alamos, died on 18 November 2004 at a retirement community near Santa Barbara, California. He is also remembered for his membership in the Atomic Energy Commission (AEC); his longtime chairmanship of Caltech’s division of physics, mathematics, and astronomy; and his service as the university’s provost.
Born on 31 August 1905 in Loudonville, Ohio, Bob grew up in Ann Arbor, Michigan, where he attended the University of Michigan. He was fortunate to have as a summer neighbor Harrison Randall, chairman of physics at Michigan, who steered him into physics at a time when Randall was transforming the department into one of the US leaders. Samuel Goudsmidt and George Uhlenbeck had arrived at Michigan from the Netherlands and the university had just established the renowned summer school attended by Niels Bohr, Enrico Fermi, J. Robert Oppenheimer, and many others.
Bob studied engineering physics and then did a graduate thesis under Goudsmidt in theoretical work on hyperfine structure in 1930. He pursued a two-year National Research Council fellowship at Caltech (1930–31) and at MIT (1931–32). While at MIT, he had occasion to report on the recent discovery of the neutron, which may have raised his interest in nuclear physics.
He returned to Ann Arbor in 1932, stayed on without an appointment because of the Depression, and began experimental work in hyperfine structure. In 1934 he became an instructor at Columbia University, where he met and became friendly with I. I. Rabi. He left in 1935 for Ithaca, New York, where he joined Cornell University as an instructor. Three years later, Bob initiated a program on slow-neutron cross sections using a time-of-flight apparatus and a 15-inch (!) cyclotron built by M. Stanley Livingston. He collaborated with Hans Bethe on an encyclopedic review article on nuclear physics, one in a series of three articles that were published in Reviews of Modern Physics in 1936 and 1937.
In the fall of 1940, while the neutron work was still active, Bob went to MIT’s Radiation Laboratory, where he headed the indicator group under the overall direction of Lee A. Dubridge and later led the radar receiver group. Bob was persuaded by Oppenheimer, though, to join Los Alamos in early 1943 as chairman of the experimental physics division and, later, the bomb physics division. At the time, there were plans to convert Los Alamos to a military lab, but Bob made it clear that he would resign if that happened. It never did.
After World War II, Bob returned to Cornell as director of the nuclear lab but was called away to advise the US delegation to the United Nations on international control of nuclear energy. After the failure of the Baruch Plan, the early attempt to give the UN oversight of nuclear power and atomic weapons, Bob joined the AEC as its only scientist member. He led AEC efforts to restart the production of atomic weapons and to support research, and helped found Brookhaven National Laboratory. He also pursued efforts to design breeder reactors. In 1949 Bob resigned with the intention of returning to Cornell.
Dubridge, however, had accepted the presidency of Caltech in 1946 and asked Bob to join him as chairman of the division of physics, mathematics, and astronomy. After some arm-twisting by Dubridge, Bob reconciled himself to a career in administration and accepted the position. One of his first moves as chairman was to talk to Richard Feynman, who Bob knew was thinking of leaving Cornell. After complicated negotiations—Bob encouraged Feynman to borrow his car and explore Hollywood—Feynman was persuaded to come to Caltech. Bob also initiated a high-energy physics program at Caltech by arranging to build a 600-MeV electron synchrotron.
In 1955 Bob brought Murray Gell-Mann to Caltech to cement the university’s outstanding position in elementary particle theory. At about the same time, together with Dubridge and Jesse Greenstein, he initiated a radio astronomy program establishing the Owens Valley Radio Observatory, and thus added to Caltech’s leading position in observational astronomy.
Bob continued as an adviser to the AEC and as a member of President Dwight D. Eisenhower’s Science Advisory Committee. In 1959 he was a member of the US delegation on nuclear test ban negotiations. He stepped down as Caltech’s division chairman in 1962 to become the university’s first provost, a position he held until 1970. He remained on the faculty until his retirement in 1976. He and his wife, Jean, moved in the late 1980s to a retirement community.
Bob served the US and international communities well. He was president of the American Physical Society (1964–65), chair of the International Union of Pure and Applied Physics (1969–72), and chair of the Universities Research Association (1970–73).
A strong administrator with firm views and clear principles, Bob defended academic freedom when Linus Pauling was severely criticized by some university trustees. He insisted that Caltech retain ties to Pauling after Pauling resigned. He oversaw the university’s conversion to coed status. And he had a clear idea of how he expected the university to operate. He always consulted widely with senior colleagues before acting on academic matters, but then was decisive.
Bob had many friends at Caltech and nationally who greatly miss his wise counsel.
