Retired Caltech Physicist Robert Walker Dies; Worked on Manhattan Project as Grad Student

PASADENA, Calif.-Robert Walker, a retired physics professor at the California Institute of Technology, died January 4 in New Mexico. A graduate student who worked on the Manhattan Project during World War II, he was 85 years old at the time of his death.

Born June 29, 1919, in St. Louis, Walker earned his bachelor's degree at the University of Chicago and was a doctoral student at Cornell University when he joined the effort to produce the atomic bomb. While on the Manhattan Project he worked both at Los Alamos and the University of Chicago. He finished his doctorate in physics in 1948, and after an additional year at Cornell as a postdoctoral researcher he was hired as an assistant professor at Caltech.

Walker became an associate professor in 1953 and a full professor in 1959. During his time on the faculty he served as executive officer for physics. He retired in 1981 and moved to the Santa Fe area.

Walker's specialty was experimental high-energy physics, and for many years he worked on the Caltech synchrotron, first as one of the co-developers with colleagues Robert V. Langmuir and Bruce Rule, and as a researcher for the accelerator's entire 30-year lifetime. For many years, he was also the principal investigator of Caltech's contract with the Department of Energy and its predecessors to do experimental and theoretical research in elementary particle physics.

According to Charles Peck, a professor emeritus of physics at Caltech who earned his doctorate under Walker's tutelage, Walker's collaborative research utilizing the synchrotron helped lay the foundation work that led to what is now known as the Standard Model of elementary particle physics. In particular, Peck said, Walker's work involved pion photoproduction (in which a proton or neutron is bombarded with a high-energy photon which converts into a pi meson). His research was also useful to his longtime Caltech colleague Richard Feynman in his theoretical studies of the underlying mechanisms of particles.

"Bob was also a superb teacher," Peck said. "He taught a course in the mathematical methods of physics, and also courses in quantum mechanics and particle phenomena."

Walker also co-wrote a textbook, Mathematical Methods of Physics, with Jon Mathews.

After retiring from Caltech, Walker built harpsichords at his home near Santa Fe, Peck said.

He is survived by two children, Robert Craig Walker and Jan Walker Roenisch.