Charles Louis Critchfield was born in Shreve, Ohio, on June 7, 1910, and grew up in Washington, D.C.[1][2] He received his B.S. (1934) and M.A. (1936) degrees in mathematics from George Washington University, where he also earned a PhD in Physics (1939) under the direction of Edward Teller.[3]
In April 1944, the Manhattan Project experienced a crisis when Emilio Segrè discovered that plutonium made in nuclear reactors would not work in Thin Man.[13] In response, Oppenheimer completely reorganized the laboratory to focus on development of an implosion-type nuclear weapon in August. He reassigned Critchfield to a new Gadget Division under Robert Bacher, as the leader of the Initiator group.[14] This group was responsible for the design and testing of the "Urchin" neutron initiator, which provided a burst of neutrons that kick-started the nuclear detonation of the Fat Man weapon.[15]
Postwar
Critchfield left Los Alamos in 1946 and returned to George Washington University, but soon left to join Wigner at the Oak Ridge National Laboratory.[3][16] In 1947 he became an assistant professor at the University of Minnesota, where he participated, with Edward P. Ney and John R. Winckler, in a classified project to improve balloon technology.[17] Here, with Leland S. Bohl, he invented and patented the natural shape balloon,[18] and participated, with Ney and his student Sophie Oleksa, in an early search for primary cosmic ray electrons.[19]
In 1955, after advancing to full professor at Minnesota, Critchfield became vice president for research at the Convair division of General Dynamics.[20] Here, he worked on the Atlas family of rockets, which began as a series of ICBMs and evolved into launch vehicles for Project Mercury and many other space missions. He also created the Convair Scientific Research Laboratory whose staff were expected to serve as consultants for the company's engineering divisions and to carry out basic scientific research. In 1957, Critchfield's student William C. Erickson joined the staff, and created the Clark Lake Radio Observatory.[21] In 1963, this facility, where observations focused on long wavelength radio waves, was transferred to the University of Maryland, where Erickson had become a professor. Although the original observatory has been abandoned, similar research continues at the much larger Long Wavelength Array in central New Mexico.[22]
Later life
In early November 1959, President Dwight D. Eisenhower's Secretary of DefenseNeil H. McElroy selected Critchfield to be head of the Defense Advanced Research Projects Agency. McElroy hoped that Critchfield would be able to fix the nation's troubled missile program, but Critchfield was reluctant to serve at the director's $19,000 salary. McElroy then offered to let Critchfield serve without pay, with the government paying only his expenses of $15 per day, while allowing Critchfield to continue to draw his Convair salary of around $40,000. Critchfield accepted this offer, but ran into a storm of political and media criticism over the conflict of interest involved in heading an agency that did $4 million worth of business with Convair each year. Critchfield then withdrew his name from consideration.[23][24]
In 1961, Critchfield accepted a professorship at the University of Wisconsin, but before he moved to Madison, his friends at Los Alamos, J. Carson Mark and Norris Bradbury offered him a position there that he took instead.[20] He held this position until he retired in 1977, but he continued his association with the laboratory until his death after a long battle with cancer on February 12, 1994. His obituary in Physics Today was written by Carson Mark, Louis Rosen, Edward Teller, and Roger Meade.[3]
Charles Critchfield is buried next to his wife, Jean, in Guaje Pines Cemetery in Los Alamos County, New Mexico.[25]
^Schweber, Silvan S. (2012). Nuclear Forces: The Making of the Physicist Hans Bethe. Cambridge, Massachusetts: Harvard University Press. p. 352. ISBN978-0-674-06587-1.
^"Members 1940–1941"(PDF). Bulletin No. 10. See p xii. The Institute for Advanced Study. October 1941. Retrieved May 16, 2012.
^"Biography of Robert Kent". Array of Contemporary American Physicists. American Institute of Physics. Archived from the original on March 6, 2016. Retrieved April 18, 2012.
^Hoddeson, Lillian; Meade, Roger A.; et al. (2004). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. Cambridge University Press. pp. 316–319. ISBN978-0-521-54117-6.
^Ney, Edward; Winckler, John (1956). Final Report: Research and Development in the Field of High Altitude plastic Balloons, Vol XVI. University of Minnesota.
^Erickson, W. C. (September 8–11, 2004). "Lessons Learned from the Clark Lake Experience". In Kassim, N. (ed.). ASP Conference Series, Vol. 345. Santa Fe, New Mexico: Astronomical Society of the Pacific. p. 89. Bibcode:2005ASPC..345...89E.