Cyclotrons were the most powerful particle accelerator technology until the 1950s when they were superseded by the synchrotron, and are still used to produce particle beams in physics and nuclear medicine. The largest single-magnet cyclotron was the synchrocyclotron built between 1940 and 1946 by Lawrence at the University of California, Berkeley, which could accelerate protons to 730 mega electron volts (MeV). The largest cyclotron is the multimagnet TRIUMF accelerator at the University of British Columbia in Vancouver, British Columbia, which can produce 500 MeV protons.