Linac beam colliding with a stored beam revisited

A system was suggested to collide an accelerator beam, such as a linac electron beam, with the stored positron beam in a storage ring, and a simple theory of the performance of the system was worked out in terms of the beam parameters of the linac and the storage ring. In cases where the available accelerator can deliver beam energies greater than those which can be stored in the ring, a higher center-of-mass energy can be attained with this system than with the storage ring alone. This is the situation we now find ourselves in at SLAC with the linac capable of supplying beams of about twice the energy of those we can store in PEP and with developments in progress to raise the linac energy still more. 2 refs