First Cyclotron	Early accelerators and accelerator builders
Ernest Lawrence’s first cyclotron, built in 1930 had an energy of 80 thousand volts and a circumference of 32 inches. Today’s most powerful accelerator, the Tevatron at the Department of Energy’s Fermilab, has an energy of 2 trillion electron volts and a circumference of four miles. In between came many intermediate machines, including Lawrence’s 27-inch and 60-inch cyclotrons, and the first colliding-beam machine, an electron-positron collider built by physicists at Princeton and Stanford Universities. Each generation of particle accelerators and detectors builds on the accomplishments of the previous ones, raising the level of technology ever higher.