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Edward Cruetz (January 23, 1913 – June 27, 2009) was an American physicist who was a group leader on the Manhattan Project at the Metallurgical Laboratory and the Los Alamos Laboratory during World War II. After the war he became a professor of physics at the Carnegie Institute of Technology. He was Vice President of Research at General Atomics from 1955 to 1970. He published over 65 papers on botany, physics, mathematics, metallurgy and science policy, and was the holder of 18 patents relating to nuclear energy.

Early life

Edward Chester Cruetz was born on January 23, 1913, in Beaver Dam, Wisconsin, the son of Lester Cruetz, a high school history teacher, and Grace Smith Cruetz, a general science teacher. He had two older brothers, John and Jim, and a younger sister, Edith. The family moved to Eau Claire, Wisconsin, in 1916, Monroe, Wisconsin, in 1920, and to Janesville, Wisconsin, in 1927. He played a number of musical instruments, including the mandolin, ukulele and trombone. He played in the school bands Janesville High School and Monroe High School. At Janesville he played tenor banjo in a dance orchestra called Rosie’s Ragador's, and timpani with the school orchestra at Monroe. He also played left guard on the American football teams at Janesville and Monroe. He expressed an interest in chemistry, biology, geology and photography.

After graduating from Janesville High School in 1929, rook a job as a bookkeeper at a local bank. In 1932, his brother John, who had graduated from the University of Wisconsin with a degree in electrical engineering, persuaded him to go to college as well. John suggested that "if you aren’t sure what part of science you want, take physics, because that's basic to all of them." Cruetz later recalled that this was the best advice he ever got. He entered the University of Wisconsin and studied mathematics and physics. Money was scarce during the Great Depression, especially after his father died in 1935. To pay his bills, Cruetz worked as a dishwasher and short order cook, and took a job taking care of the physics laboratory equipment. In 1936, his senior year, he taught physics labs.

Faculty Cruetz encountered at the University of Wisconsin included Julian Mack, who gave him a research project to do in his junior year, Ragnar Rollefson, Raymond Herb, Eugene Wigner and Gregory Breit. Cruetz remained at Wisconsin as a graduate student after being awarded his Bachelor of Science (B.S.) degree in 1936, working for Herb upgrading departmental Van de Graaff generator from 300 to 600 KeV. With this done the question became what to do with it, and Breit suggested that it had previousl;y been observed that high-energy gamma rays were produced when lithium was bombarded with protons at 440 KeV. Cruetz therefore wrote his 1939 Doctor of Philosophy (Ph.D.) thesis on Resonance Scattering of Protons by Lithium, under Breit's supervision. Cruetz married Lela Rollefson, a mathematics student at Wisconsin, and the sister of Ragnar Rollefson, on September 13, 1937. The couple had three children, two sons, Michael and Carl, and a daughter, Ann Jo.

Wigner moved to Princeton University in 1938, and soon after Cruetz received an offer as well. Princeton had been given a 36-inch (910 mm) magnet by the University of California, which had been used to build am 8 MeV cyclotron. They wanted Cruetz to help get it operational. He later recalled:

On my third day in Princeton I was invited to give a short report on my thesis work. There were usually two or three speakers at these "Journal Club" meetings. This time the speakers were Niels Bohr, Albert Einstein, and Ed Creutz. To be on the same program with these two giants of scientific accomplishments was breathtaking. Just before the meeting began, my sponsor, Delsasso, asked me, "Say, Creutz, have you met Einstein yet?" I had not. Delsasso took me over to where Einstein was sitting in sweatshirt and tennis shoes, and said, "Professor Einstein, this is Creutz who has come to work on our cyclotron." The great man held out his hand, which seemed as big as a dinner plate, and said in an accented voice, "I’m glad to meet you, Dr. Creutz." I managed to wheeze out, "I’m glad to meet you, too, Dr. Einstein."

But it was Bohr who electrified the audience with his news from Europe of the discovery by Lise Meitner and Otto Frisch of nuclear fission. Physicists rushed to confirm the results. Cruetz built an ionization chamber and a linear amplifier out of radio vacuum tubes, coffee cans and motorcycle batteries, and with this apparatus the physicists at Princeton were able to confirm the results.

World War II

In the early years of World War II between 1939 and 1941, Wigner led the Princeton group in a series of experiments involving uranium and two tons of graphite. In early 1942, Arthur Compton concentrated the Manhattan Project's various teams working on plutonium at the University of Chicago. This brought in many top scientists including Herbert Anderson, Bernard Feld, Enrico Fermi, Leo Szilard and Walter Zinn from Columbia, and Edward Cruetz, Gilbert Plass, Eugene Wigner and John Wheeler from Princeton University. Weinberg became a protégé of Wigner.

Wigner led the Theoretical Group at the Metallurgical Laboratory that included Alvin Weinberg, Katherine Way, Gale Young and Edward Creutz. The group's task was to design the production nuclear reactors that would convert uranium into plutonium. At the time, reactors existed only on paper, and no reactor had yet gone critical. In July 1942, Wigner chose a conservative 100 MW design, with a graphite neutron moderator and water cooling. The choice of water as a coolant was controversial at the time. Water was known to absorb neutrons, thereby reducing the efficiency of the reactor; but Wigner was confident that his group's calculations were correct and that water would work, while the technical difficulties involved in using helium or liquid metal as a coolants would delay the project.

After the United States Army Corps of Engineers took over the Manhattan Project, it gave responsibility for the detailed design and construction of the reactors to DuPont. There was friction between the company and Wigner and his team. Major differences between Wigner's reactor design and DuPont's included increasing the number of process tubes from 1,500 in a circular array to 2,004 in a square array, and cutting the power from 500 MW to 250 MW. As it turned out, the design decision by DuPont to give the reactor additional tubes came in handy when neutron poisoning became a problem for the B Reactor at the Hanford Site. The extra tubes allowed a greater fuel load to overcome the poisoning. Without them the reactor would have had to be run at low power until enough of the boron impurities in the graphite had been burned up to allow it to reach full power, which would have delayed full operation by up to a year.

Later life

Notes

1. ^ Hinman, George; Rose, David (2010). Edward Chester Cruetz 1913-2009 (PDF). Biographical Memoirs. Washington, D.C.: National Academy of Sciences. Retrieved September 21, 2014.
2. ^ Cruetz, Edward (January 23, 1996). "Obituary" (PDF). Retrieved September 21, 2014.
3. ^ "Oral History Transcript — Dr. Edward Creutz". American Institute of Physics. January 9, 2006. Retrieved September 21, 2014.
4. Cruetz, Edward (1939). "Resonance Scattering of Protons by Lithium". Physical Review. 55 (9): 819–824. doi:10.1103/PhysRev.55.819. {{cite journal}}: Unknown parameter |month= ignored (help)
5. Raman, Roger; Panarella, E. (2009). Current trends in international fusion research: proceedings of the sixth symposium. Ottawa: NRC Research Press. p. 353. ISBN 9780660198903.
6. Weinberg 1994, pp. 11–12.
7. Szanton 1992, pp. 217–218.
8. Weinberg 1994, pp. 22–24.
9. Szanton 1992, pp. 233–235.
10. Weinberg 1994, pp. 27–30.

References

• Szanton, Andrew (1992). The Recollections of Eugene P. Wigner. Plenum. ISBN 0-306-44326-0. {{cite book}}: Invalid |ref=harv (help)
• Weinberg, Alvin (1994). The First Nuclear Era: The Life and Times of a Technological Fixer. New York: AIP Press. ISBN 1-56396-358-2. {{cite book}}: Invalid |ref=harv (help)

Category:1913 births Category:2009 deaths Category:People from Beaver Dam, Wisconsin Category:American physicists Category:University of Wisconsin alumni Category:Carnegie Mellon University faculty Category:Manhattan Project people