MODEL RELEASED. Cockroft-Walton generator at Fermi National Accelerator Laboratory (Fermilab), near Chicago, USA. The generator forms the first stage of subatomic particle acceleration. Electrons are added to hydrogen atoms in an ion source inside the generator, resulting in hydrogen ions (a proton with two electrons) emerging from the high voltage accelerator with an energy of 750 thousand electronvolts (KeV). The protons travel through increasingly powerful accelerators before entering the Tevatron proton-antiproton collider. Here, a technician is grounding any remaining electricity as a safety precaution after the generator has been used. Photographed in 1998. Accelerator operator is MARTY MURPHY.