 The protons and antiprotons were accelerated in opposite directions, crossing paths in the CDF and DØ detectors to collide at 1.96 TeV.To hold the particles on track the Tevatron used 774 niobium-titanium superconducting dipole magnets cooled in liquid helium producing the field strength of 4.2 tesla.The field ramped over about 20 seconds as the particles accelerated.