He published over 65 papers on botany, physics, mathematics, metallurgy and science policy, and held 18 patents relating to nuclear energy.

After the war ended, Creutz accepted an offer to come to the Carnegie Institute of Technology, where he became the head of its physics department and its nuclear research center in 1948.

While there he accepted an offer to become vice president for research and development and the director of its John Jay Hopkins Laboratory for Pure and Applied Science at General Atomics.

To pay his bills, Creutz worked as a dishwasher and short order cook, and took a job taking care of the physics laboratory equipment.

[2] Creutz encountered several members of the faculty at the University of Wisconsin, including Julian Mack, Ragnar Rollefson, Raymond Herb, Eugene Wigner and Gregory Breit.

With this done, the question became what to do with it, and Breit suggested that it had previously been observed that high-energy gamma rays were produced when lithium was bombarded with protons at 440 keV.

[1] Creutz therefore wrote his 1939 Doctor of Philosophy (Ph.D.) thesis on Resonance Scattering of Protons by Lithium,[4][5] under Breit's supervision.

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.

"[2] 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.

Creutz 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.

[2] 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 as a neutron moderator.

[3] Wigner led the Theoretical Group that included Creutz, Leo Ohlinger, Alvin M. Weinberg, Katharine Way and Gale Young.

In July 1942, Wigner chose a conservative 100 MW design, with a graphite neutron moderator and water cooling.

[1][10] Frederick Seitz and Alvin Weinberg later reckoned that the activities of Creutz and his group may have reduced the time taken to produce plutonium by up to two years.

[1] The discovery of spontaneous fission in reactor-bred plutonium due to contamination by plutonium-240 led Wigner to propose switching to breeding uranium-233 from thorium, but the challenge was met by the Los Alamos Laboratory developing an implosion-type nuclear weapon design.

[11] In October 1944, Creutz moved to Los Alamos,[10] where he became a group leader responsible for explosive lens design verification and preliminary testing.

[14] After the war ended in 1945, Creutz accepted an offer from Seitz to come to the Carnegie Institute of Technology as an associate professor, and help create a nuclear physics group there.

[2] Creutz in turn recruited a number of young physicists who had worked with him at Princeton and on the Manhattan Project in Chicago and Los Alamos, including Martyn Foss, Jack Fox, Roger Sutton and Sergio DeBenedetti.

One 1966 paper, published in the New York Botanical Garden Journal was on Apetahia raiateensis, a rare flower found only on the island of Raiatea in French Polynesia.

[2] In 1955 and 1956, Creutz spent a year at Los Alamos evaluating its thermonuclear fusion program for the Atomic Energy Commission.

He moved to La Jolla, California, as its vice president for research and development,[1][2] and was concurrently the director of its John Jay Hopkins Laboratory for Pure and Applied Science from 1955 to 1967.

[2][18] His appointment at the National Science Foundation ended in 1977, and Creutz became director of the Bernice Pauahi Bishop Museum in Honolulu.