July 27, 1904|
Cooperstown, New York
|Died||July 14, 1996
|Alma mater||Massachusetts Institute of Technology (B.A., S.M.)
Princeton University (Ph.D.)
|Doctoral advisor||Henry DeWolf Smyth|
|Doctoral students||Edward Mills Purcell|
|Known for||Nuclear mass measurements
Director of the Trinity test
Kenneth Tompkins Bainbridge (July 27, 1904 – July 14, 1996) was an American physicist at Harvard University who did work on cyclotron research. His precise measurements of mass differences between nuclear isotopes allowed him to confirm Albert Einstein's mass-energy equivalence concept. He was the Director of the Trinity test of the Manhattan Project, which took place July 16, 1945. Bainbridge called the Trinity explosion a "foul and awesome display" and remarked to J. Robert Oppenheimer immediately after the test, "Now we are all sons of bitches." This marked the beginning of his dedication to ending the testing of nuclear weapons and to efforts to maintain civilian control of future developments in that field.
Born in Cooperstown, New York, Bainbridge attended the Massachusetts Institute of Technology from 1922 to 1926, earning B.A. and S.M. degrees in electrical engineering. Upon completing his work at MIT, he enrolled at Princeton University. Over the previous few years, he had developed an interest in physics, and chose to pursue this new interest at Princeton. In 1929, he was awarded a Ph.D. in his new field.
Bainbridge enjoyed a series of prestigious fellowships after graduation, first awarded by the National Research Council, then the Bartol Research Foundation, and finally the Guggenheim Memorial Foundation. When his Guggenheim fellowship expired, he accepted an associate professorship at Harvard University and began working on a pair of cyclotrons. Bainbridge's work at Harvard resulted in his recruitment as leader of the MIT radiation laboratory's radar project. He worked with several notable physicists at the laboratory, including Hans Bethe and Robert Bacher. Their next assignment would call for the assembly of an atomic bomb.
In 1932, Bainbridge developed a mass spectrometer with a resolving power of 600 and a relative precision of one part in 10,000. He used this instrument to verify the equivalence of mass and energy, E = mc2.
By establishing accurate comparisons of the masses of the light particles concerned in nuclear disintegrations, particularly that of 7Li, discovered by Cockcroft and Walton, he achieved a noteworthy triumph in the experimental proof of the fundamental theory of Einstein of the equivalence of mass and energy.
In May 1943, Bainbridge joined the Project Y staff at Los Alamos. First he led E-9, which was charged with instrumentation development. After the lab reorganization of 1944, he worked under George Kistiakowsky as X-2 leader. In this position, he was in charge of "gadget" engineering and test preparations. On July 16, 1945, Bainbridge and his colleagues detonated an implosion bomb. After the explosion of the atom bomb he turned to J.R.Oppenheimer and said, "Now we are all sons of bitches."
Bainbridge was relieved that the Trinity test had been a success, relating in a 1975 Bulletin of the Atomic Scientists article, "I had a feeling of exhilaration that the 'gadget' had gone off properly followed by one of deep relief. I wouldn't have to go to the tower to see what had gone wrong."
Bainbridge returned to Harvard after the war, and initiated the construction of a 96-inch synchro-cyclotron, which has since been dismantled. From 1950-1954, he chaired the physics department at Harvard. During those years, he drew the ire of Senator Joseph McCarthy for his aggressive defense of his colleagues in academia. Throughout the 1950s, Bainbridge remained an outspoken proponent of civilian control of nuclear power and the abandonment of nuclear testing. In 1976, Bainbridge retired from Harvard. He died in 1996 at the age of 91.
- Pound, Robert V. (January 1997). "Obituary: Kenneth Tompkins Bainbridge". Physics Today 50 (1): 80–82. doi:10.1063/1.881651.
- "The Trinity Test". Los Alamos National Laboratory. Retrieved 2012-11-18.
- Audi, Georges (2006-04-01). "The history of nuclidic masses and of their evaluation". International Journal of Mass Spectrometry 251 (2–3): 85–94. arXiv:physics/0602050. Bibcode:2006IJMSp.251...85A. doi:10.1016/j.ijms.2006.01.048. Retrieved 2008-04-11.
- Bainbridge, Kenneth T. (July 1933). "The Equivalence of Mass and Energy". Phys. Rev. 44 (2): 123. Bibcode:1933PhRv...44..123B. doi:10.1103/PhysRev.44.123.2.
- Aston, Francis William. Mass Spectra and Isotopes. London: Edward Arnold & Co. p. 85.
- "Book of Members, 1780-2010: Chapter B". American Academy of Arts and Sciences. Retrieved 5 May 2011.
- "Los Alamos National Laboratory: History: Building the Atomic Bomb: Trinity". Los Alamos National Laboratory. Retrieved 2009-05-11.
- "Memorial Minute -- Kenneth Tompkins Bainbridg". Harvard University Gazette. May 7, 1998. Retrieved 2009-07-16.
- Wilson, Richard. A Brief History of the Harvard University Cyclotrons. Harvard University Press. Online version retrieved on 2008-09-15.
- Biographical memoirs: Kenneth Bainbridge
- Biography at Los Alamos
- Obituary from Harvard
- Annotated bibliography for Kenneth Bainbridge from the Alsos Digital Library for Nuclear Issues
- National Academy of Sciences Biographical Memoir