The eRHIC Ring-Ring Collider Design

The eRHIC ring-ring collider is the main design option for the future lepton-ion collider at Brookhaven National Laboratory. The baseline design is presented in the eRHIC Zero^th-Order Design Report (ZDR) [1]. We report on progress made during the past year including possible interaction region design changes, upgrade efforts on RHIC (the ion ring), and results of a new design study on the e-ring. The interaction region revision is based on a new scheme for the main detector design. RHIC upgrades are being pursued to ensure luminosity and ion polarization goals of the ring-ring option in the baseline design will be met. Higher current operation of the lepton storage ring is under serious consideration as a result of better understanding of beam-beam interaction effects.