Optics design with longer L* for the final focus system of Compact Linear Collider 380 GeV

The Compact Linear Collider (CLIC) plans to start operation at a center-of-mass energy of 380 GeV. This paper reports on various optimizations of the CLIC 380-GeV Final Focus System (FFS). Analytical approximations have been used to guide the numerical optimizations. The first optimization consists of the reduction of the vertical beta function at the interaction point to 70 μm, which is at the limit of the hourglass effect. The second optimization focuses on minimizing the lengths of the final doublet quadrupoles to reduce the chromaticity. The third optimization searched for alternative optics configurations, resulting in the implementation of a novel dispersion profile along the FFS. This alternative optics boosts both total and peak luminosities by 7% and 9%, respectively.