Fermilab has the most powerful accelerator in the world. This process of particle acceleration begins with a small bottle of hydrogen located in the electrostatic Preaccelerator, which is where everything starts. Fermilab's Preaccelerator is based on the Cockcroft-Walton design. It produces H- ions (hydrogen consists of a proton and an electron. The H- ion has an extra electron added) with an energy level of 750 keV (1 eV = one electron volt). The H- ions travel through the Linac and enter the Booster where both electrons are stripped off leaving a proton.