D. Trbojevic

Electron Cooling of RHIC

We report progress on the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon at storage energy using 54 MeV electrons. The electron source will be a superconducting RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum electron bunch frequency is 9.38 MHz, with bunch charge of 20 nC. The R&D program has the following components: The photoinjector and its photocathode, the superconducting linac cavity, start-to-end beam dynamics with magnetized electrons, electron cooling calculations including benchmarking experiments and development of a large superconducting solenoid. The photoinjector and linac cavity are being incorporated into an energy recovery linac aimed at demonstrating ampere class current at about 20 MeV.

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 Zeroth-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.

Dynamic aperture evaluation for the RHIC 2009 polarized proton runs

In this article we numerically evaluate the dynamic apertures of the proposed lattices for the coming Relativistic Heavy Ion Collider (RHIC) 2009 polarized proton (pp) 100 GeV and 250 GeV runs. One goal of this study is to find out the appropriate {beta}* for the coming 2009 pp runs. Another goal is to check the effect of second order chromaticity correction in the RHIC pp runs.

Electron-ion collisions at RHIC using a high intensity self-polarizing electron ring

We consider the design of an electron-ion collider realized by adding a self-polarizing electron ring to the existing RHIC collider. It would provide polarized electron-proton and unpolarized electron-ion beam collisions in the center of mass energy range of 30-100 GeV and at luminosities up to 10/sup 33/ cm/sup -2/s/sup -1/ for e-p and 10/sup 31/ cm/sup -2/s/sup -1/ for e-Au collisions. An electron storage ring lattice has been developed which provides a short polarization time for an electron beam in the 5-10 GeV energy range and which satisfies the luminosity goals. We describe the modifications to the RHIC interaction region layout required for both efficient beam separation and also for longitudinal electron and proton beam polarization at the collision point.