The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams with luminosities up to 10^34cm^{-2}s^{-1} in the center mass energy range of 20-140 GeV. Besides high luminosity and high polarization, it is also recommended for the EIC design to incorporate a possible second interaction region (IR). In this article, we evaluate the dynamic aperture of the Hadron Storage Ring (HSR) design lattice with two IRs. The large nonlinear chromaticities from the two IRs will be compensated with multiple arc sextupole families. The tolerances of IR magnetic field errors are to be determined.

The Electron-Ion Collider (EIC) at Brookhaven National Laboratory will feature an electron storage ring that will circulate polarized beams with energies up to 18 GeV. Recently a study has been undertaken to extend the minimum energy from 6 GeV to 5 GeV. As the solenoid-based spin rotators around the interaction point require specific bending angles that depend on the energy range, this change results in major changes to the geometry. Moreover, avoiding interference of the electron beamline with the other beamlines in the tunnel, as well as with the tunnel walls, is a formidable challenge, especially at the location of the large-diameter superconducting solenoids. In this contribution, the details of the modified spin rotators, geometrical layout, and optics of the revised lattice are presented.

The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams with luminosities up to 10^34cm^{-2}s^{-1} in the center mass energy range of 20-140 GeV. To compensate the geometric luminosity loss due to a large crossing angle in the EIC, crab cavities are to be installed on both sides of interaction point (IP) to construct a local closed crabbing bump. However, for the current design lattice of the Hadron Storage Ring, the crab dispersion bump is not closed because the ideal 180 degree horizontal phase advance between the crab cavities on both sides of IP cannot be achieved. We carried out numerical simulations to evaluate the negative impacts with this imperfectly closed crab dispersion bump. We also simulated various schemes to close the crab dispersion.

The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams with luminosities up to 10^34cm^{-2}s^{-1} in the center mass energy range of 20-140 GeV. Preliminary beam-beam simulations resulted in an optimum working point of (.08, .06) in the Electron Storage Ring (ESR). However, during the ESR polarization simulation study this working point was found to be less than optimal for electron polarization. In this article, we present beam-beam simulation results in a wide range tune scan to search for optimal ESR design tunes that are acceptable for both beam-beam and polarization performances.

The Electron-Ion Collider is gearing up for "Critical Decision 2", the project baseline with defined scope, cost and schedule. Lattice designs are being finalized, and preliminary component design is being carried out. Beam dynamics studies such as dynamic aperture optimization, instability and polarization studies, and beam-beam simulations are continuing in parallel. We report on the latest developments and the overall status of the project, and present the plans for future activities.