BNL, Upton, New York, USA
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
JLab, Newport News, Virginia, USA
The Electron-Ion Collider (EIC), presently under construction at Brookhaven National Laboratory, will collide polarized high-energy electron beams with hadron beams, achieving luminosities up to 1 × 1034 cm¿2 s¿1 in the center-of-mass energy range of 20-140 GeV. To achieve such high luminosity, we adopt high bunch intensities for both beams, small and flat transverse beam sizes at the interaction point (IP), a large crossing angle of 25 mrad, and a novel strong hadron cooling in the Hadron Storage Ring (HSR) to counteract intra-beam scattering (IBS) at the collision energy. In this talk, we will review the beam dynamics challenges in the design of the EIC, particularly the single-particle dynamic aperture, polarization maintenance, beam-beam interaction, impedance budget and instabilities. We will also briefly mention some technical challenges associated with beam dynamics, such as strong hadron cooling, multipoles and noises of crab cavities, power supply current ripples, and the vacuum upgrade to existing beam pipes of the Hadron Storage Ring of the EIC.
BNL, Upton, New York, USA
The RHIC collider physics program, in particular its polarized proton and low energy heavy ion components, present unique challenges for maintaining collider performance in the presence of space charge effects. Polarized beam performance is especially sensitive to emittance increases, since they decrease both the luminosity and polarization. Operation of the collider with gold beams at sub-injection energies (down to 3.85 GeV/n Au) with space charge tune shifts up to 0.1 required special care to optimize both the ion lifetime and its interaction with the electron-beam cooler. We describe the operational experience in these modes and some of the mitigation efforts.