Clifford Glenwood Shull Collection

Clifford Glenwood Shull, a 1937 alum of Carnegie Institute of Technology (“Carnegie Tech,” now Carnegie Mellon), was a 1994 Nobel Prize winner in Physics. Shull’s pioneering work with Ernie Wollan in neutron scattering while a physicist at Oak Ridge from June of 1946 through 1955 led to his Nobel Prize.

Shull was born on September 23, 1915 in the Glenwood section of Pittsburgh, Pennsylvania. His first exposure to physics was at Schenley High School where he was in Paul Dysart’s class. Dysart held a PhD in the field and Shull was quite impressed by his lectures and his laboratory demonstrations.

In the fall of 1933, Shull began his undergraduate studies at Carnegie Tech. In his Nobel autobiography, he mentions Harry Hower teaching his freshman physics class and cementing his interest in physics as a course of study. He also makes a special mention of Professor of Physics Emerson Pugh. It was Pugh’s guidance during his final two years that led to Shull continuing his study of physics at New York University in 1937.

In 1937, Shull began his graduate studies at New York University. Graduate students in physics at New York University typically joined a research group in the department. Shull joined the nuclear physics group that was led by Frank Myers and Robert Huntoon. As a graduate student, Shull was involved with the first work with the 200 keV Cockroft-Walton generator. This generator was used for accelerating deuterons and its first experiment studied the D-D nuclear reactions.

In his third year of graduate study, Shull was chosen to assist Frank Myers with the construction of a 400 keV Van de Graaff generator. The Van de Graaff generator was used for accelerating electrons. The plan was to have Shull repeat the electron double-scattering (EDS) experiment, a direct test for electron spin. Myers left on sabbatical and Richard Cox filled in as Shull’s supervisor. Upon successful completion of his thesis, Double Scattering of Electrons as a Search for Electron Polarization, Shull took his Doctor of Philosophy degree in Physics in June of 1941.

In his first year at New York University, Clifford Shull was introduced to Martha-Nüel Summer by fellow physics graduate student Craig Crenshaw. Martha-Nüel was doing her graduate work in history at nearby Columbia University. They married in 1941 after Shull had taken his doctorate degree. Together they had three sons - John, Robert (also a physicist), and William.

The first stop in Shull’s work life was with the Texas Company (now known as Texaco) in Beacon, New York. His work with the Texas Company dealt with determining the microstructure of catalysts used in the production of high performance aviation fuel. His work at the Texas Company was deemed important for the war effort --the company successfully fought Shull’s recruitment to the Manhattan Project.

Not long after the end of World War II, Shull visited the Clinton Laboratory (now Oak Ridge National Laboratory). Intrigued by the work being done at the Clinton Laboratory he took a job there in 1946. There he began work with Ernest Wollan that would lead to his Nobel Prize nearly 50 years later. Their work centered on neutron diffraction patterns of crystals and materials. While working with the Clinton Pile, Shull’s work included the study of NaH and NaD crystals, the structure of ice, ferromagnetic crystals, paramagnetic substances and antiferromagnetic substances. They also used neutron diffraction to study the transition elements and the magnetic structure of their alloys.

Shull left Oak Ridge National Laboratory in August of 1956 for an opportunity to teach and guide graduate students in their research with the MITR-1 facility at the Massachusetts Institute of Technology (MIT). For the first 16 months, Shull was temporarily relocated to the Brookhaven National Laboratory. During this time he collaborated with BNL researchers and advised in the construction of the MITR-1’s neutron diffraction equipment. He served as a consultant at Brookhaven for a number of years after this temporary assignment.

The MITR-1 reactor became operational in July of 1959. Professor Shull summarized his studies at MIT in his Nobel autobiography as including: “internal magnetization in crystals, development of polarized beam technology, dynamical scattering in perfect crystals, interferometry, and fundamental properties of the neutron.” When the reactor was shutdown for modification and overhaul from May of 1974 until 1976, he was able to collaborate with Oak Ridge scientists (W.C. Koehler and R. M. Moon) on the Cu(Fe) Kondo system and the limitations on the accuracy of polarized neutron diffractometry.

Clifford Shull retired from MIT in 1986 --eight years prior to being awarded the Nobel Prize. Shull mentioned how he should have shared the prize with Wollan at the Nobel ceremony in 1994, but Wollan had passed on in 1984 and the Nobel Prize is not awarded posthumously.

After his receipt of the Nobel Prize, Shull dutifully made the lecture rounds that are typically demanded of those that achieve this level of recognition. He also contributed to science policy guidance - especially that involving research with neutrons. On March 31, 2001, Clifford Shull died of kidney failure in Lexington, Massachusetts. Throughout his life he was also honored with the Buckley Prize from the American Physical Society in 1956, election to the American Academy of Arts & Sciences in 1956, election to the National Academy of Science in 1975, the Humboldt Senior Scientist Award in 1979, the Distinguished Scientist Award (from the Governor of Tennessee) in 1986, the Gregori Aminoff Award in 1993, and the I.M. Frank Prize in 1994. The Neutron Scattering Society of America has established the Clifford G. Shull Award and the UK Antarctic Place-Names Committee named a group of rocks in the Crystal Sound the “Shull Rocks” to commemorate his use of neutron diffraction to determine the position of hydrogen atoms in ice.