RF Driven Linear Colliders

Abstract

The main problem encountered in our attempts to produce conceptual designs for e⁺e⁻ colliders in the TeV range is the very large luminosity required, which should increase with the square of energy and should exceed 10³³ cm⁻²s⁻¹ — at least — for 2 TeV in the centre of mass. Making the main linacs superconducting would be ideal, since the high efficiency of transferring power to the beam would permit very high beam power. Unfortunately, the limited accelerating gradients attainable with superconducting cavities — and also the high cryogenic losses associated with really high gradients if these were attainable — would lead to a total length in the 100 km range if not beyond, considered excessive by most. Some of the advantages of RF superconductivity may, however, be maintained by using a superconducting drive linac in a two-beam scheme, as discussed below.