Forging a National Laboratory System in a Time of Peril
by Paul Preuss
On September 1, 1939, Germany invaded Poland. On September 3, France and Great Britain declared war on Germany; on the same day a German submarine torpedoed and sank the passenger liner Athenia off the coast of Scotland, with the loss of 118 lives. Ernest Lawrence’s brother John, returning from Europe, was the last person into a lifeboat after saving others.
There were rumors from Stockholm that no Nobel Prizes would be presented in 1939. But on November 9 the Associated Press announced that Lawrence had won “for the invention and development of the cyclotron and for results obtained with it, especially with regard to artificial radioactive elements.” Eventually his medal and certificate arrived at the Swedish consulate in San Francisco, to be presented at a University of California ceremony on February 29, 1940.
The Palomar of the Infinitesimal
Lawrence used the occasion to promote his dream of a cyclotron that could accelerate protons to 100 million electron volts (100 MeV). Its vacuum chamber would be wider than Mount Palomar’s 200-inch mirror, and its magnet would weigh 3,000 tons — or maybe 4,000 tons, or maybe more — and cost three-quarters of a million dollars. Or maybe one-and-a-quarter million. Or maybe more. The university would have to raise the money from private sources, but a Nobel Prize made that seem possible.
Some scoffers objected that nothing very significant had been done with Lawrence’s cyclotrons, an objection put firmly to rest in the summer of 1939 when Luis Alvarez and Robert Cornog, using the 60-inch cyclotron, discovered stable helium-3 — which every scientist believed should be radioactive — and a few days later used the 37-inch cyclotron to make radioactive hydrogen-3, better known as tritium — which every scientist thought should be stable.
Close on these discoveries came Martin Kamen’s work with carbon isotopes with both the 37-inch and 60-inch cyclotrons, leading to his discovery of radioactive carbon-14 on February 27, 1940 — two days before Lawrence’s Nobel Prize ceremony, at which the discovery was announced.
More significant than sour grapes about the cyclotron’s worth were scientific warnings about its physical limitations. Because its speed increases as its orbit widens, a particle spiraling in a cyclotron’s magnetic field stays in sync with the alternating electric field that accelerates it. But as it approaches the speed of light, the particle’s mass also increases, eventually throwing the beam out of focus.
Hans Bethe was the first to raise the specter of a cyclotron’s “relativistic limit,” which James Chadwick estimated at “about 10 million volts for protons, 15 million volts for deuterons and alpha particles.” This pessimistic guess was left in the dust as Robert Wilson, Edwin McMillan, Donald Cooksey and others among Lawrence’s boys continually came up with clever ways to shape magnetic fields and keep cyclotron beams focused.
Still, a 100-MeV cyclotron seemed to defy the laws of nature. Historians J.L. Heilbron and Robert W. Seidel write that Lawrence “bruited a solution in the style of the Old West: put a million or two volts on the dees and drive the beam home before it knows it has been defocused.”
Lawrence’s confidence was enough to persuade his fans, who included, among many others, Warren Weaver, director of the Rockefeller Foundation’s Division of Natural Sciences. In the spring of 1940 the Rockefeller Foundation agreed to fund the new machine to the tune of $1.4 million. It would be a 184-inch cyclotron, to be built on Charter Hill overlooking the Berkeley campus; its magnet would weight 4,500 tons, and for safety its controls would be located 150 feet away.
To house it, distinguished architect Arthur Brown, whose works included San Francisco’s City Hall, Opera House, and Coit Tower, designed a 90-foot-high dome. This was an aesthetic advance over Lawrence’s original inspiration. While entertaining visitors at the Folies Bergère during the Golden Gate International Exposition on Treasure Island, Lawrence had become distracted by the steel-framed dance hall and inquired whether the university might acquire it to house his new cyclotron when the Exposition closed.