A family of physicists
Julian Knause Knipp was born on January 18, 1910, in Champaign, Illinois. His father, Charles Knipp, was a professor of physics at the University of Illinois, so Julian grew up surrounded by the science he would spend his life on.
He graduated from the University of Illinois with honors in mathematics in 1931, then went to Harvard, where he earned a master’s degree in 1932 and a Ph.D. in physics in 1935. In 1936 he joined the physics faculty at Purdue University.
Fission fragments and Edward Teller
In 1941 Julian and Edward Teller published “On the Energy Loss of Heavy Ions” in Physical Review, a theory of how fast, heavy, charged particles such as the fragments of a split uranium nucleus slow down as they pass through matter. Physicists still refer to the “Knipp–Teller” treatment of the problem. It was exactly the kind of nuclear physics that would soon be needed at Los Alamos.
The MIT Radiation Laboratory
During World War II, Julian worked at the MIT Radiation Laboratory in Cambridge, Massachusetts, the center of American microwave radar research. At its peak the “Rad Lab” employed about 4,000 people and designed roughly half of the radar systems the U.S. military used in the war, including the kinds of search and fire control radar carried by destroyers like Howard’s USS Fletcher.
When the war ended, the lab’s knowledge was recorded in the 28-volume MIT Radiation Laboratory Series, the standard reference on radar and microwave engineering for a generation. Julian was a co-author of Volume 7, Klystrons and Microwave Triodes (McGraw-Hill, 1948), with Donald R. Hamilton and J. B. Horner Kuper. The book covers the microwave tubes, above all the reflex klystron, that served as the heart of wartime radar receivers.
Los Alamos and the Manhattan Project
The family remembers that Julian also worked at Los Alamos, New Mexico, as part of the Manhattan Project. The American Institute of Physics holds a photograph of him with colleagues at a Los Alamos Scientific Laboratory employee party. We are still gathering the details of his work there.
Building physics at Tufts
After the war Julian taught at Iowa State College from 1946 to 1955. On September 1, 1955, he became chairman of the physics department at Tufts University, then a small liberal arts college with little research tradition.
A 2019 Tufts Magazine history credits his hiring with starting Tufts’ transformation into a leading research university. As the article puts it, “every serious particle physicist in the country knew Julian Knipp.” Under his leadership the department won Atomic Energy Commission support for high-energy physics research, beginning in 1957, and joined major national experiments. In his years as chair, the physics department brought in more outside grant money than the rest of the School of Arts and Sciences combined. In 1967 he was appointed dean of the School of Arts and Sciences.
Julian retired in 1975 as professor emeritus. In 1987 the physics and astronomy library in Robinson Hall was renamed the Julian K. Knipp Library. He died in 1990.
This chapter is a work in progress. We are still researching Julian’s wartime work at Los Alamos, and we would welcome photographs, letters or recollections from anyone who knew him.
Sources
- Julian Knipp Papers, MS227, Tufts Archival Research Center, Tufts University.
- Sol Gittleman, “The Department That Built a University,” Tufts Magazine, Spring 2019.
- D. R. Hamilton, J. K. Knipp and J. B. H. Kuper, Klystrons and Microwave Triodes, MIT Radiation Laboratory Series, Vol. 7 (McGraw-Hill, 1948).
- J. Knipp and E. Teller, “On the Energy Loss of Heavy Ions,” Physical Review 59, 659 (1941).
- “Julian Knipp with others at a Los Alamos Scientific Laboratory employee party,” AIP Emilio Segrè Visual Archives.
- University Laboratory High School (Urbana), Class of the Century profile, “Julian Knause Knipp, Class of 1926.”
- Family recollections.