Cyclotron is a machine that accelerates electrically charged atomic particles to high energies. It is a type of particle accelerator that makes the particles travel in a circle. Cyclotrons accelerate particles ranging in mass from protons to heavy nuclei. Most reach energies of from 10 million to 50 million electronvolts. A few attain even higher energies. (One electronvolt is the amount of energy needed to move an electron through an electrical potential difference of 1 volt.)