Tuning the Compact Linear Collider 380 GeV final-focus system using realistic beam-beam signals

Abstract

Tuning of the final-focus system of a linear e−e+ collider is a challenging problem due to the strong nonlinearities of the system and small transverse beam sizes at the interaction point. To have reliable performance of a collider, nominal luminosity must be reached quickly under a set of various imperfections. Measuring luminosity at high energies is a nontrivial task, and, to get a precise measurement, many collisions must be sampled. Therefore, it is desirable to use other beam-beam signals for faster tuning. This paper studies the use of beamstrahlung and incoherent pairs in an extensive simulation study including static imperfections. Tuning results of the nominal lattice are compared to an updated lattice with a smaller vertical beam size at the interaction point. Finally, recovery time after machine downtime and misalignment of components due to ground motion is also studied.