sentence: Protons are parts of atoms with a positive charge.
sentences_before: The LHC starts with hydrogen atoms, and ionizes the atoms' electrons so that only protons are left.
sentences_after: The protons are moved around the Large Hadron Collider at very high speeds by giant supercooled electromagnets. These magnets have to be very cold to work and they are cooled by liquid helium. It then reverses and creates mass.
concept_name: proton
headings: Large Hadron Collider
categories: Buildings and structures in Switzerland Nuclear physics