Science Wars: Return of the Cyclotron
Physicists Robert Cahn and Natalie Roe examine the 1931 cyclotron.
CREDIT: Roy Kaltschmidt/Berkeley Lab
You might think an object that can project particles at the speed of light would be accustomed to traveling in a hurry. But that wasn’t the case for one of the world’s first cyclotrons, which finally completed its journey home to Berkley, Calif. this month, after 75 years of delayed travel plans.
The cyclotron, which was once used to boost protons to energies of 1.22 million electron volts, was built in 1932 at the University of California at Berkley by Ernest O. Lawrence. The young physicist, eager to show off his ground-breaking invention, loaned it to the London Science Museum in 1938.
For the past 60 years or so, the University of California has been trying to reclaim this important part of its history. And the decades of cutting through red tape have finally paid off for the university, as the artifact has now been returned to the laboratory that bears its inventor’s name, the Lawrence Berkeley National Laboratory.
The brass cyclotron, which measures 26 inches from end to end and whose accelerating chamber measures just 11 inches in diameter, was a major improvement upon the linear accelerators that proceeded it. This “proton merry-go-round,” as Lawrence once called it, was used to boost proton energies and then project them towards a target at nearly the speed of light. Once the charged protons hit their target, scientists were able to examine the smashed contents of microscopic particles.
The “atom-smashers” that Lawrence invented helped launch the field of modern particle physics and served as the predecessors of today’s huge accelerators, such as the Large Hadron Collider, which measures 5.4 miles in diameter. Smaller cyclotrons are also used in hospitals as part of the equipment needed to help treat cancer with particle therapy.