Crocker Nuclear Laboratory control room
Crocker Nuclear Laboratory control room.

Vintage Venue: UC Davis Crocker Lab Celebrates 50th Anniversary

Stepping inside the Crocker Nuclear Laboratory control room is like transporting onto the set of a 1960s sci-fi flick. Bakelite knobs and flashing switches parade across sofa-sized control banks. 

But control room operator Randy Kemmler has a more modern analogy. “I feel like I’m in The Simpsons,” said Kemmler, referring to the Springfield Nuclear Power Plant, where Homer Simpson dozes and drools. “All I need is the dozen doughnuts.”

The vintage controls run a 50-year-old cyclotron, one of the few particle accelerators of its kind still working in the United States. Tucked inside a modest building in the heart of the UC Davis campus, the Crocker Nuclear Laboratory opened in April 1966.

Past and present employees recently gathered to celebrate the cyclotron’s five decades of discovery and innovation. During the event, historic photographs lined the walls of the lab’s tall cargo bay, and tours revealed atomic-era machinery still at work.

“There is a lot of significant history here,” said engineer Brian Devine. “Crocker Lab is one of the best-kept secrets on campus.”

Early work at Crocker Lab focused on basic nuclear research — the physics of neutrons and protons. But UC Davis scientists rapidly branched out into new areas, including air quality, medical treatments and spacecraft radiation testing. This diversity helped the lab weather times when money was tight.

“A facility like this could have never survived with a single story,” said retired research chemist Manuel Lagunas-Solar. “The key to success was flexibility and versatility.”


The Crocker Nuclear Laboratory is internationally recognized for its work in five key areas:

Radiation testing of electronics destined for space

Crocker Lab’s beam can be tuned to produce radiation similar in type and energy to that seen in space. Both the Pioneer and Voyager spacecraft were tested at Crocker, said former director Tom Cahill. “I held in my hands hardware that has now left the solar system,” Cahill said. Industry partners also come to Crocker to study terrestrial radiation at altitude, such as in cities like Denver, Colorado.

Non-destructive analysis of historical documents

In the 1980s, historians started to visit the cyclotron to analyze ink and paper without damaging historical documents. Priceless objects — including a Gutenberg Bible and parts of the Dead Sea Scrolls — made quiet trips into the cyclotron. The program ended as scientists developed new technologies for dating documents. At right, Tom Cahill inspects a historical document in an undated photograph.

Air-quality research

Cahill has often said the lab’s air quality program was inspired by his smoggy student years at UCLA. Cahill discovered a way to use the cyclotron for detailed measurements of the composition of airborne pollutants. With his colleagues, Cahill showed that lead pollution from freeways drifted over local neighborhoods. His research also included monitoring national parks and wilderness areas for Clean Air Act violations.

Radioactive isotopes for medical use

In 1972, physicist John Jungerman and research chemist Manuel Lagunas-Solar developed a new method for making iodine 123, a thyroid cancer diagnostic tool now available from commercial suppliers. The lab produced about 25 medically-useful isotopes over the years, Lagunas-Solar said.

Proton therapy radiation treatment of ocular melanoma

Crocker Lab’s huge industrial machine has treated more than 1,500 people for eye cancer with its proton beam therapy. The beam penetrates the eye and then stops, targeting its cancer-killing energy on the tumor itself. With a cure rate of 97 percent, the patient care is a highlight for the staff. “It’s a fantastic service we provide,” director Tony Wexler said.

Today, the cyclotron continues to host a diverse group of programs. Director Tony Wexler sees the cyclotron continuing to operate many years into the feature. Demand for semiconductor testing is increasing, work on air quality continues, and eye tumor treatment could expand into new areas, he said. Researchers are currently testing a potential therapy for macular degeneration, which is in Phase II clinical trials.

The biggest challenge to continued research is keeping the cyclotron running. “It’s like a beautiful old car in Cuba — we just keep repairing it until the repairs cost too much,” Wexler said.


Particle accelerators propel electrically charged particles such as protons to nearly the speed of light. In a cyclotron, a powerful magnetic field bends the path of particles so they travel in ever-widening orbits, gaining speed each time. The process is similar to pushing a swing. The ultimate goal is smashing these whirling particles into a target.

The cyclotron was invented in Berkeley in the 1930s by Ernest Lawrence, the namesake of Lawrence Berkeley National Laboratory. The Crocker Nuclear Lab’s 60-inch magnet was sculpted for a Berkeley cyclotron used to discover new elements, including plutonium.

When the Berkeley cyclotron was decommissioned in the 1950s, Lawrence offered the 220-ton magnet to his former student John Jungerman, head of the UC Davis Department of Physics. The magnet formed the core of a new 76-inch particle accelerator at Davis. The facility was named Crocker Nuclear Laboratory in honor of UC Regent William Crocker, who was a generous supporter of the Berkeley Lab.

Cyclotrons were once the nation’s best source of radioactive isotopes and energetic particles. The post-World War II boom in atomic research meant more than 40 of these million-dollar machines (in 1950s dollars) were built throughout the United States. But cyclotrons fell out of favor with the advent of nuclear reactors and powerful linear accelerators.

“There are not many like it anymore,” said engineer Brian Devine.

Replacements for the cyclotron’s original parts have long since gone out of stock; UC Davis machinists and engineers design and fabricate replacements instead. Repairs challenge the mechanical know-how of laboratory staff.

“There’s no manual, and there’s nothing you can buy off the shelf,” Devine said. “It’s like working on a UFO.” 

— Becky Oskin, content strategist in the UC Davis College of Letters and Science

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