 Another 240 NbTi quadrupole magnets were used to focus the beam.The initial design luminosity of the Tevatron was 1030 cm−2 s−1, however, following upgrades, the accelerator had been able to deliver luminosities up to 4 cm−2 s−1.On September 27, 1993, the cryogenic cooling system of the Tevatron Accelerator was named an International Historic Landmark by the American Society of Mechanical Engineers.