This is a diagram of a cyclotron by Ernest Lawrence of the Berkeley Radiation Laboratory, from the original patent application.
History: a legacy from Berkeley
The cyclotron was originally built at the Berkeley Radiation Laboratory (now the Lawrence Berkeley National Laboratory), and some components date back to the 1930s.
At Berkeley, the 60-inch machine had been used to discover new elements, including plutonium.
In the late 1950s, Berkeley lab director Ernest Lawrence offered the machine to UC Davis physics professor John Jungerman, who had approached Lawrence for support in building a new machine.
Old machine donated to University of Chile
At the time, UC Davis was operating a smaller, 22-inch cyclotron built by the Department of Physics. That machine was later donated to the University of Chile.
Raising money, modifying the design and carrying out the transfer took some years.
The 60-inch machine was redesigned as a 77-inch cyclotron, in collaboration with Oak Ridge National Laboratory and the Naval Research Laboratory in Washington, D.C. Many of the new parts were made or modified in the Department of Physics' machine shop.
In 1964, the giant magnets arrived from Berkeley and work began on the building to house them. 10-foot thick, 30-ton blocks of concrete blocks were put in place to act as radiation shielding.
‘One evening, we got a bit of current, and someone had the idea of putting a penny on a probe and pushing it in.’
Founding Director John Jungerman
First beam
By April 1966, with the dedication ceremony just a week away, the UC Davis physicists had yet to coax a beam from their new baby.
"One evening, we got a bit of current, and someone had the idea of putting a penny on a probe and pushing it in," recalled Jungerman, founding director of the Crocker Nuclear Laboratory and now a professor emeritus. When the penny was pulled out, it set off the Geiger counter -- bombardment with protons had altered some of its atoms, making it radioactive.
"Somehow, out of the filing cabinets came a lot of champagne bottles," Jungerman said.
The cyclotron was officially dedicated a week later. The facility was named the Crocker Nuclear Laboratory in honor of UC Regent William Crocker, who had been a generous supporter of the original Berkeley Radiation Lab.
Basic and applied physics
Early work at the lab concentrated on fundamental nuclear physics, including internationally recognized work on neutrons by Jungerman, F. Paul Brady and William J. Knox and of alpha particles and gamma rays by James E. Draper.
Thomas Cahill, later the lab's second director, joined the lab in 1967 and his graduate student and current director, Bob Flocchini, studied X-ray physics.
Dan Shadoan, programmer supervisor at the Crocker, is surrounded by lab history: He shakes hands with Bob Flocchini, current lab director, while founding director John Jungerman, left, and the lab's second director, Tom Cahill look on. (Karin Higgins/UC Davis photo)
In the 1960s, the U.S. government's Atomic Energy Commission funded nuclear facilities at universities around the country. But in 1971 the Nixon administration abruptly shut off funding. Most of the nuclear facilities at universities closed down.
But the Crocker lab survived by finding new applications for cyclotron science in areas such as air quality, testing historical documents, food safety and cancer treatment.
"The Davis campus is always willing to support interdisciplinary and applied research, and this is a perfect example," said Flocchini, a professor in the Department of Land, Air and Water Resources.
Following some recent equipment upgrades, Flocchini sees the cyclotron continuing to operate for many years to come. Work on air quality is continuing; demand for semiconductor testing is increasing; eye tumor treatment is expanding and could grow into new areas, he said.