Bertram Neville Brockhouse

Bertram Neville Brockhouse, professor emeritus at McMaster University, who shared the 1994 Nobel Prize in Physics with Clifford Shull, died on 13 October 2003 in Hamilton, Canada.

Bert was born in Lethbridge, Canada, on 15 July 1918 and grew up in Vancouver. He began his elementary school education in a one-room schoolhouse a few miles from the family farm. Completing high school at the height of the Depression, and with limited employment prospects, he moved with his family to Chicago in 1935. There, he took evening courses in radio repair and design that earned him a position as a laboratory assistant in an electrical firm and allowed him to repair radios on his own time. After three years in Chicago, the family returned to Vancouver.

In 1939, soon after Canada was at war with the Axis powers, Bert enlisted in the Royal Canadian Navy and went to sea as a sonar operator before eventually rising to the position of electrical sub-lieutenant. After his discharge from the navy in 1945, he took advantage of a veterans’ program to begin studies at the University of British Columbia, where he majored in physics and mathematics.

On completion of his bachelor’s degree in 1946, he obtained summer work in the electrical standards section of the National Research Council in Ottawa. During that summer, Bert, a motorcycle enthusiast in his youth, rode his motorcycle three-quarters of the way across North America, from Vancouver to Ottawa, via Chicago—no mean feat. He subsequently completed a master’s degree in physics at the University of Toronto. His doctoral studies there, initially supervised by Edward Bullard, earned him his PhD in 1950 with a thesis on the effects of stress and temperature on the magnetic properties of ferromagnetic materials.

That same year, Bert began work at Chalk River Nuclear Laboratories of the National Research Council of Canada’s Atomic Energy Project near Ottawa. There, he would do the work that won him the Nobel Prize. He collaborated with Donald Hurst, Myer Bloom, G. Goldschmidt, and N. Page in studying the resonant scattering of slow neutrons by strong absorbers. Ultimately, members of the group proposed the idea of studying the inelastic scattering of slow neutrons, an effort deemed feasible because Chalk River’s National Research Experimental (NRX) reactor was then the world’s highest flux beam reactor.

By 1952, Bert had designed and built a triple-axis machine to measure the frequency distribution of phonon excitations in crystals. After much experimentation with a variety of techniques both at Chalk River and at Brookhaven National Laboratory over the next few years, Bert and his collaborators ultimately developed the famed triple-axis spectrometer with all angles adjustable so that it was possible to carry out scans as a function of energy at fixed momentum transfer—the so-called constant-Q technique. By 1958, a triple-axis spectrometer was operating at Chalk River’s new National Research Universal reactor, with much enhanced neutron flux as compared with NRX, and the stage was set for great progress. Triple-axis spectrometers adorn high-flux beam reactors around the world to this day, and the constant-Q technique is in frequent current use.

Using the constant-Q triple axis and other inelastic neutron scattering techniques, Bert and his collaborators were very quickly able to carry out a remarkable series of seminal measurements. Those included measurements of the phonon dispersion curves in metals such as aluminum and lead, semiconductors such as silicon and germanium, and insulators such as the alkali halides. Bert’s work measuring insulators, done in collaboration with David Woods and William Cochran, led to the development of the famed shell model.

In addition to the seminal work on phonon dispersion curves, Bert pioneered studies of other elementary excitations in solids including spin-wave excitations (magnons) and crystal-field excitons. Key members of the Chalk River group at that time, in addition to those previously named, included Alec Stewart, Roger A. Cowley, and Gerald Dolling. Of course, the facilities at Chalk River and Bert’s own successful experimentation drew many great visiting scientists from around the world including P. Iyengar, M. Sakamoto, K. Rao, L. Becka, H. Watanabe, B. Dasannacharya, and J. Bergsma. Even after Bert moved to McMaster, the group that he established at Chalk River continued to flourish, and many scientists, including ourselves, received their first training in neutron scattering there.

From 1962 until he retired in 1984, Bert was a professor of physics at McMaster. His presence was instrumental in building up a research-intensive department through the 1960s, and he served as chairman of the physics department at McMaster from 1967 to 1970. An interdisciplinary materials research institute at McMaster, founded by Howard Petch and James Morrison in 1969, was renamed the Brockhouse Institute for Materials Research in 1995. There, as at Chalk River, Bert mentored many students who have gone on to have significant careers in physics.

Although greatly admired for his intellect and novel ways of approaching problems, Bert is remembered for his affection and his humble, gracious manner. Shortly after the announcement that he was a winner of the Nobel Prize, for example, Bert told a gathering of Canadian undergraduate physics students at McMaster that he used to think that his work was not so important, but recent events had forced him to reconsider. He is also remembered for his love of the arts: He often sang opera at work and he appeared in a number of amateur theater productions including a George Bernard Shaw play and Gilbert and Sullivan operettas. Even during the most hectic and productive time in his career, Bert found time to be a devoted family man with six children and, ultimately, 10 grandchildren.

Although Bert’s passing is mourned by his many friends and colleagues, we have been inspired by a life of great accomplishment.