The cyclotron began as a library doodle and a junkyard magnet
One evening in 1929 Ernest Lawrence flipped through a journal in the Berkeley library and saw a diagram of a straight-line particle accelerator. He imagined curling it into a spiral between the poles of a magnet. That idea became the cyclotron, a Nobel Prize, and the birth of Big Science.
Lawrence was born on 8 August 1901 in Canton, South Dakota, the son of teachers descended from Norwegian immigrants. His younger brother John became a pioneer of nuclear medicine, and his boyhood best friend, Merle Tuve, also became a leading physicist. After a chemistry degree from the University of South Dakota and a physics master's from Minnesota, he earned a Yale doctorate in 1925 on the photoelectric effect in potassium vapour. Berkeley hired him in 1928, and two years later he was its youngest full professor.
The problem he tackled was energy. Breaking apart atomic nuclei needed particles pushed to millions of volts, and a linear design like the one by Rolf Widerøe would grow absurdly long. A magnetic field could instead hold protons in a spiral while repeated kicks sped them up. With graduate students such as M. Stanley Livingston he built working machines, and each success prompted a bigger one. An 80-ton magnet found rusting in a Palo Alto junkyard, originally built in World War I for a transatlantic radio link, went into a 27-inch model. He patented the cyclotron in 1934.
The instruments outpaced the discoveries. In 1932 Cockcroft and Walton in England split lithium with protons at energies Lawrence's smaller machine could already reach, a missed chance. Still, his Radiation Laboratory, an official university department from July 1936, became the world's leading centre for nuclear physics and promoted medical uses of radioisotopes. He won the 1939 Nobel Prize in Physics.
In World War II Lawrence adapted the approach into calutrons, devices that separated uranium isotopes electromagnetically, and a vast plant known as Y-12 was built at Oak Ridge, Tennessee. It was inefficient but it worked. Afterwards he campaigned for large government-funded science and backed Edward Teller's push for a second weapons laboratory, which he sited at Livermore. He died on 27 August 1958. Both the Berkeley and Livermore laboratories now bear his name, as does element 103, lawrencium, discovered at Berkeley in 1961.
Source: Ernest Lawrence
