University of California, Berkeley
University of California, Berkeley
Many important Manhattan Project contributions resulted from the scientists and technology of the University of California, Berkeley. They first entered the war effort through the effort of the MAUD Committee, engaging Ernest Lawrence and the university in the war effort. In addition, Berkeley was the center for theoretical physics in the United States and spawned such notables as J. Robert Oppenheimer, Glenn Seaborg, and Emilio Segre.
The Rad Lab
The "Rad Lab" was the short name for the Radiological Laboratory at the University of California, Berkeley. Its director was Nobel laureate Ernest O. Lawrence. He gained recognition for his 60" cyclotron, a type of particle accelerator first invented in the early 1930s. After a meeting with British scientist Mark Oliphant, he became a major proponent of nuclear research.
Known as “atom smashers,” cyclotrons accelerate atoms through a vacuum and use electromagnets to induce collisions at speeds up to 25,000 miles per second. The results of such experiments provided valuable clues about the behavior of atoms and was the driving force behind the electromagnetic separation of uranium that formed the basis for the Y-12 complex at Oak Ridge.
The Rad Lab still exists today. It was renamed The Lawrence Berkeley National Laboratory and continues scientific research on a variety of topics including plasma accelerators, magnet technology, and alternative energy sources.
1942 Summer Study Group
Much theoretical research and thought for the Manhattan Project also took place at Berkeley. In the spring of 1942, J. Robert Oppenheimer, also based out of the University of California, Berkeley, worked with his former postdoctoral student Robert Serber and two current students Eldred Nelson and Stan Frankel on the problems of neutron diffusion and hydrodynamics.
To review this work and the general theory of fission reactions, Oppenheimer convened a summer study at Berkeley in June 1942. Theorists Hans Bethe, John Van Vleck, Edward Teller, Felix Bloch, Richard Tolman and Emil Konopinski concluded that a fission bomb was feasible. The chief uncertainties lay in the experimental values for neutron cross-sections -the probabilities that neutrons would strike a fissionable atom and either cause it to fission, be absorbed or be scattered -and neutron multiplication -the numbers of neutrons that would be produced in fission and cause other atoms to fission in a rapid chain reaction. The scientists suggested that such a reaction could be initiated by assembling a critical mass -an amount of nuclear explosive adequate to sustain it - either by firing two subcritical masses of plutonium or uranium 235 together or by imploding (crushing) a hollow sphere made of these materials with a blanket of high explosives. Until the numbers were better known, this was all that could be done. "Everyone seemed to be saying, well, that's all settled, let's talk about something interesting," Serber recalled.
Teller saw another possibility: By surrounding a fission bomb with deuterium and tritium, a much more powerful "superbomb" might be constructed. This concept was based on studies made by Bethe before the war of energy production in stars. When the detonation wave from the fission bomb moved through the mixture of deuterium and tritium nuclei, they would fuse together to produce much more energy than fission, just as elements fused in the sun produce light and heat. Bethe was skeptical, and as Teller proposed scheme after scheme for a "superbomb," Bethe refuted each one.
When Teller raised the possibility that an atomic bomb might ignite the atmosphere, however, he kindled a worry that was not entirely extinguished until the Trinity test, even though Bethe showed, theoretically, that it couldn't happen. The summer conferences, the results of which were later summarized by Serber in "The Los Alamos Primer" (LA-1), provided the theoretical basis for the design of the atomic bomb, which was to become the principal task at Los Alamos during the war, and the idea of the H-bomb, which was to haunt the Laboratory in the postwar era. Seldom has a physics summer school been as portentous for the future of mankind.
[The text for this page was taken and adapted from Los Alamos National Laboratory article "The Berkeley Summer Study".]