• Gregory Loew

Perry Baker Wilson,1927-2013

Professor Perry Baker Wilson, one of the accelerator physics pioneers at Stanford and SLAC, died on November 30, 2013 in Redwood City, Calif. at age 86.

Perry Wilson was born February 24, 1927 in Norman, Oklahoma. Around that time, his father, Roy Arthur Wilson, was a geology professor at the University of Oklahoma in Norman, but when Perry turned 7, his mother died and he was sent to Spokane, Washington to live with his uncle’s family. Wilson attended Lewis & Clark high school and graduated as Valedictorian on January 22, 1945. At this point, he was sent to Navy Pier in Chicago where he qualified for Electronics School. He then spent two years in the U.S. Navy through the end of WWII and 1946 as a technician on the USS Shangri-La in the South Pacific, fixing radars and radios. This activity opened up his interest in electronics and in the importance of knowledge and education.

Upon returning to the U.S., Wilson attended Gonzaga University in Spokane for two years. He then went on to Washington State University, in Pullman, Wash. from where he graduated with a B.S. in Physics in June 1950, and an M.S. in Physics in 1952. Wilson subsequently came to Stanford University in 1952 and earned his Ph.D. in Physics in 1958. His thesis was on a “Microwave Electron Velocity Spectrograph,” for which he was supervised by Prof. Edward Ginzton in the Microwave Laboratory.

In July 1958, Wilson became a staff physicist at the Linfield Research Institute in McMinnville, Oregon. In July 1959, he returned to Stanford University as a Research Associate in the High Energy Physics Laboratory (HEPL) for five years. From October 1964 through August 1966, he was Associate Director for Operations at HEPL, and then Senior Research Associate until June 1968. He then took a one-year leave of absence as a Visiting Scientist at CERN in Geneva, Switzerland. During much of this period, Wilson did pioneering research on superconducting lead and niobium cavities for linear accelerators and racetrack microtrons. Many of his publications during these years were co-authored by W.M. Fairbank, H. A. Schwettman, J. P. Turneaure, T .I.Smith, and B. H. Wiik, all working at HEPL in this field.

Upon his return to the U.S. in August 1969, Wilson joined SLAC as a Senior Research Associate. His first assignment was to explore the possibility of converting the SLAC three-kilometer-long copper linear accelerator to a higher duty-cycle, higher-gradient superconducting niobium machine. Together with a sizeable group of accelerator physicists at SLAC, Wilson worked on this project for about three years, also exploring the possibility of using superconducting niobium cavities for future circular storage rings. In the end, it was realized that the niobium technology was not ready to produce high enough accelerating gradients to make it useable, and the linac project was discontinued. It took another twenty five years before the superconducting technology became practical to build structures for linear and circular machines with niobium at other institutions in the world. Yet in retrospect, Wilson’s role in this research was historically crucial for the entire accelerator community.

In fact, by 1974, as the need to increase the electron and positron beam energy of the SLAC linac for particle physics research had not gone away, Wilson was inspired by his work on superconducting cavities to come up with a major invention. With the help of colleagues Z. D. Farkas and H. A. Hoag, he developed a very ingenious device dubbed SLED (for SLAC Energy Development). The idea was based on the fact that it is possible to store and time-compress microwave energy from a high power klystron in an intermediate low-loss room temperature copper cavity, and then rapidly discharge this enhanced energy into the accelerator, thereby producing higher power and gradients. Two-hundred and forty of these SLED systems were eventually deployed along the SLAC accelerator and increased its energy from 22 to 32 Giga electron volts. Years later, in 1991, Wilson and Farkas received the IEEE PAC Technology Award for the SLED invention.

After SLED, Wilson turned his attention to the problems of beam loading and bunch lengthening in high energy storage rings, and to the calculation and measurement of longitudinal and transverse wakefields in linear accelerators. In this area of research, he spent a considerable amount of time mentoring younger SLAC accelerator physicists such as Karl Bane with whom he wrote a number of important publications. This work eventually led Wilson in the late 1980’s and early 1990’s to produce several seminal papers on electron-positron linear collider designs, and associated power sources with binary radiofrequency pulse compression systems to drive these colliders. He also applied his insight into wakefields to the formulation of wakefield acceleration, including its transformer ratio limit. Towards the end of his active career, Wilson also developed an interest in the breakdown limits of high-gradient accelerator cavities and tried to figure out whether the choice of metals other than copper might support higher electric fields.

In 1974, Wilson became an Adjunct Professor at SLAC, a position he retained until1983. During this period he did another eight-month stint as Scientific Associate at CERN. In 1983, Wilson became a Professor of Applied Research at SLAC. He kept this academic position for the rest of his career until his official retirement August 31, 1997. However, he was recalled to active duty, part-time, as Professor Emeritus on an annual basis until August 2006. He continued to come to SLAC fairly regularly until his recent death.

During his career, Wilson was a consultant, with companies such as Varian Associates, and institutions such as the U.S. Naval Postgraduate School in Monterey, CA.

Wilson was a member of Phi Beta Kappa, Phi Kappa Phi, President of the Stanford Chapter of Sigma Xi in 1987-88, a Senior Member of the IEEE and a Fellow of the American Physical Society.

Wilson was always recognized as a kind, considerate and generous colleague, and he was highly respected as a scientist and a teacher of accelerator physics courses in the U.S., in Europe and in Japan. Among his extra-curricular activities, Wilson was a strong supporter of the Council for a Livable World, interested in reducing the threat posed by nuclear weapons in the world, and a member of the Henry Kendall Society (Union of Concerned Scientists).

Perry Wilson is survived by his wife, Gerda Wilson, his son Perry F. Wilson and wife Kay, his son John J. Wilson, two grandsons, Perry and Christian Wilson, and his stepson Barton Clark and wife Sophie.

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