Luminosity upgrades for the SLC

Recent performance improvements at the SLAC Linear Collider (SLC) have led to a proposal to further increase the luminosity up to a factor of four through a series of modest hardware upgrades. New final focus optics introduced in 1997 combined with permanent magnet octupoles have reduced the contribution to the final beam size due to higher order aberrations. The minimum betas achievable at the IP are presently limited by the increase in detector backgrounds as the beam is focused more strongly. By moving the final quadrupoles closer to the interaction point (IP), one can reduce the synchrotron radiation background while decreasing the IP betas. Other upgrades include increasing the bending radius in the final focus to minimize emittance dilutions due to synchrotron radiation, a fast feedforward from the linac to the final focus to cancel trajectory jitter, and a change in the horizontal damping ring partition number to reduce the emittance of the extracted beam. With these upgrades, the expected disruption enhancement should be 2.4.