The Nobel Prize in Physics 1994
Bertram N. Brockhouse, Clifford G. Shull
I was born on September
23, 1915 to my parents, David H. and Daisy B. Shull, in the
section of Pittsburgh, Pennsylvania, known as Glenwood, which
obviously relates to their selection of my middle name. I was
preceded by an older sister, Evalyn May, and an older brother,
Perry Leo, so that I grew up as the baby in the family. Both my
father and mother had origins in rural, central Pennsylvania, in
farming sections of Perry County. After moving with his then
family to the big city, Pittsburgh, my father started a small
business that evolved into a hardware store and an associated
home repair service.
My early years of growth were entirely normal and happy ones and I had the usual collection of friends and buddies, who were often seen on the ball field or on roller skates. Grade schooling was nearby, a few blocks from our home, and this led later on to junior high school in the adjoining Hazelwood section but still within walking distance of our home. Following this, I had decided to go to Schenley High School for the remaining three years of school work and this required a more troublesome commute of 45 minutes by public street car. My first interest in physics as a career speciality came during my senior year at Schenley when I took the physics course taught by Paul Dysart. Somewhat older than the usual high school teacher and with a PhD degree in his background, he was a very impressive teacher who delighted in demonstrations from his laboratory and in explaining the principles behind them. Thereafter my original interest in aeronautical engineering was in heavy competition with physical science.
It seemed natural, in view of limited family financial straights, that I should continue into college study by living at home and commuting to the Carnegie Institute of Technology (now Carnegie Mellon University). Carnegie Tech was also located in the Schenley Park district of Pittsburgh so that essentially the same commute was called for and it offered good, reputable curricula in the engineering and physical sciences. I was pleased when offered admission to the fall term of 1933 and particularly so when given a half-tuition scholarship in view of my good high school record. Once there, my interest in physics as a major subject sharpened quckly, helped along no doubt by the brilliant lectures in my freshman physics course given by Harry Hower, the chairman of the Physics Department. Hower was more aptly labeled an optical and illuminating engineer than a physicist, because of his extensive consulting activities in coastal lighthouse lens design and other architectural problems, but his lectures were delightful, inspiring and not often-to-be-missed by his students.
Shortly after my admission at Carnegie Tech, a family crisis developed when my father died unexpectedly in January, 1934. By this time, my sister had married and, with her husband, were living at home along with my brother (who had just finished college as an art major), my mother and myseelf. My brother decided to forego his art teaching and operate my father's business and this continued until I had finished Carnegie Tech in 1937. The four years spent there were entirely pleasurable ones, in spite of the time-consuming commute, and I enjoyed the association with my fellow students and professors in the department. I was able to work in the summer periods at jobs both on and off campus and this helped to meet my rather minimal expenses during the year. Among the professors, I valued very much the friendly encouragement and counsel offered by Emerson Pugh during my junior and senior years, leading to my continuance into graduate school at New York University in the fall of 1937.
New York University was then a very large university, perhaps the largest in the nation, with several distributed, more or less autonomous, campuses. I was located with the Physics Department at the University Heights campus in the upper Bronx section of New York City and my teaching assistantship provided living subsistence, teaching meaning laboratory course help and problem assignment grading. We graduate students were encouraged at an early stage to join and help in one of the half dozen or so ongoing research projects within the department. I became associated with a nuclear physics group headed by Frank Myers and Robert Huntoon, who were in the process of building a 200 keV Cockroft-Walton generator for accelerating deuterons. Much valuable experience was obtained with this exposure by Craig Crenshaw, another graduate student, and myself and we were able to help in the initial experiment with this accelerator, a study of the D-D nuclear reaction.
During the third year of my graduate study, the Department decided that it could support the construction of a new 400 keV Van de Graaff generator to be used for accelerating electrons. Frank Myers took on this responsibility with me as his assistant and the thought that it could be used to repeat the electron-double-scattering (EDS) experiment as a possible thesis topic for me. This EDS type of experiment loomed important at the time because it was considered a direct test that electrons have a spin or polarization. Several earlier experiments had given either negative or inconclusive results and it seemed worthwhile that the experiment be performed again under new conditions. The construction and testing of the new facility went smoothly and I turned to getting ready for my thesis EDS experiment. By this time, Frank Myers had decided to take his overdue sabbatical leave with Robert Van de Graaff at MIT. I was fortunate in getting Richard Cox, a senior professor in the department, to supervise and offer expert and friendly advice on my efforts. Finally after four months of data collection and analysis, the experiment was successful and I was able to prepare a thesis and take my PhD degree in June 1941.
Among the other research programs being pursued by the NYU department was the study of neutron interactions with materials as started by Alan Mitchell and carried on by Martin Whitaker. Using a Ra-Be neutron source surrounded by a paraffin howitzer, a modest beam of thermalized neutrons was available for experimentation and, during my period at the Heights, this was directed towards a search for the expected paramagnetic scattering from certain materials. Theoretical prediction of this had been given by O. Halpern and M. Johnson and their students in the Department. I was familiar with this problem through my contemporary graduate student William Bright who worked with Whitaker on the experiment and indeed found myself working on the same problem a decade later.
I have neglected to mention an important event that occurred in my first year in New York City. Through my good friend Craig Crenshaw, I was introduced to a young lady, Martha-Nuel Summer, who had recently come from South Carolina to the graduate school at Columbia University to study early American History. Our friendship flourished during the years of our professional studies and we married shortly after I took my degree and had a job in waiting. She has remained my loving companion to the present and along the way we have been favored by three fine sons, John, Robert and William, who have beautiful families of their own.
I had arranged for a position at Beacon, NY with the research laboratory of The Texas Company, and Martha and I set up housekeeping there in July 1941. This laboratory addressed problems associated with the production and use of petroleum fuels and lubricants and included a small group of physicists. I was asked to study the microstructure of catalysts using gas adsorption and x-ray diffraction and scattering as tools for characterizing the physical structure of these materials. These catalysts were used in the production of high-performance aviation fuel and this area of investigation became increasingly important after the US entry in the World War in December 1941. Of singular significance to the scientific community in the first year of our wartime activity was the growth of the Manhattan Project dealing with the development of an atomic weapon. Many scientists had been drawn into this, including a number of my old colleagues and professors from graduate school. I was encouraged to join them and would have done so except that The Texas Company would not agree to my wartime job change. The matter was finally settled in their favor by an adjudication hearing at an area manpower board and I stayed in Beacon through the war years.
My work at Beacon was interesting and challenging and gave me the opportunity of learning things about diffraction processes, crystallography and the new field of solid state physics. Through visits and early meetings of the American Society for X-ray and Electron Diffraction, I was able to know established personages such as Warren, Buerger, Fankuchen, Zachariasen, Ewald, Harker, Gingrich and Donnay. Once the war was over, my interest in participating in the exciting new developments in nuclear physics within the Manhattan Project returned, and I paid a visit to the Clinton Laboratory (now Oak Ridge National Laboratory) in Tennessee. The activity there fascinated me very much and I convinced Martha that we should move there, which we did in June 1946 along with our one and a half year old son.
It was arranged that I would work with Ernest Wollan, who had been at the Laboratory since its formation during the war period and who had just assembled a rudimentary two-axis spectrometer for obtaining neutron diffraction patterns of crystals and materials. Wollan had shown me his first powder diffraction pattern on my earlier visit and I was delighted to be able to join him in exploring how neutron patterns could be used to supplement those obtained with x-rays or electrons. Our collaboration on common problems was to continue for nearly a decade until I left Oak Ridge in 1955 for academic life at Massachusetts Institute of Technology. I regret very much that Wollan's death in 1984 precluded his sharing in the Nobel honor that has been given to Brockhouse and me since his contributions were certainly deserving of recognition.
I was attracted to MIT by the prospects of teaching and of training graduate research students at the soon-to-be-completed MITR-I research reactor on campus. This reactor was among the early group of condensed volume reactors using isotopically enriched fuel which were being explored in that period. Together with occasional post-doctoral students and a regular flow of graduate thesis students, our group carried on investigations using neutron radiation from this reactor in many fields until my retirement from MIT in 1986. These studies included: internal magnetization in crystals, development of polarized beam technology, dynamical scattering in perfect crystals, interferometry, and fundamental properties of the neutron. The opportunity of being at MIT with its fine faculty and excellent students has certainly been most stimulating and satisfying.
From Les Prix Nobel. The Nobel Prizes 1994, Editor Tore Frängsmyr, [Nobel Foundation], Stockholm, 1995
This autobiography/biography was written at the time of the award and later published in the book series Les Prix Nobel/Nobel Lectures. The information is sometimes updated with an addendum submitted by the Laureate.
Clifford G. Shull died on March 31, 2001.
Copyright © The Nobel Foundation 1994