• Q. Wu, I. Ben-Zvi, X. Chang, J. Skarita
  BNL, Upton, Long Island, New York

The proposed electron ion collider, eRHIC, requires large average polarized electron current of 50mA, which is more than 20 times higher than the present experiment results of single polarization source, such as GaAs. To achieve the current requirement of eRHIC, we have designed the multi-cathode DC electron gun for injection. 24 GaAs cathodes will be prepared and emit electrons at the arranged pattern. Despite of ultra-high vacuum and precise timing, multi-cathode DC electron gun has high demand on the electric field symmetry, magnetic field shielding, and arcing prevention. In the paper, we present the 3D simulation results of the latest model for the multi-cathode DC electron gun. The results will give guidance to the actual design in the future.

• W. Guo, S.L. Kramer, S. Krinsky, B. Nash, J. Skarita, F.J. Willeke
  BNL, Upton, Long Island, New York

NSLS-II is a third-generation light source that is being built at the Brookhaven National Laboratory. The storage ring has 30 double-bend-achromatic cells. Six 3.5-m-long damping wigglers (DW) will be installed in three straight section to lower the emittance. The civil construction of the facility started in June 2009 and major accelerator components, such as magnets and vacuum chambers, have entered production phase. This paper will summarize the physics considerations for the NSLS-II magnet specifications. In particular, we discuss the tuning range required by the lattice flexibility, and the issues which lead to the specification for the higher-order multipoles.