Comparison of Colliding and Single Beam Proton Accelerators

Above the presently available energies, the center-of-mass energy per dollar of colliding beam accelerators becomes greater than that of single beam machines. As the energy increases, the economy of colliding beams becomes more pronounced. The difficulties in using colliding beams are typical of the difficulties accompanying each step made into a higher energy region. It is argued that colliding beams are usable and that the ability to enter an energy region otherwise unattainable justifies the difficulties. Preparing for a major colliding beam installation to come into operation around 1985 is suggested.