PEP II status and plans

The PEP II B-Factory project is an e⁺e^- colliding beam storage ring complex to be built on the SLAC site. PEP II is designed to provide a luminosity of 3×10³³ cm^-2 s^-1 at a center of mass of 10.6 GeV with unequal energy beams of 3.1 and 9.0 GeV. The goal is to study CP violation in the B meson system. The project is being built by a collaboration of the Stanford Linear Accelerator Center, Lawrence Berkeley Laboratory, and Lawrence Livermore National Laboratory. DOE construction authorization was given in 1994. The asymmetric beam energies require two storage rings with the low energy ring (LER) supported above the high energy ring (HER). There will be one interaction point with head-on collisions, requiring magnetic separation of the beams, low values of the beta functions, and magnetic elements inside the solenoid of the BABAR physics detector. The high luminosity necessitates a large number of bunches requiring advances in the vacuum design, damped RF cavities, and bunch-by-bunch feedback systems. The injection scheme uses the high current, low emittance, on-energy beams available from the SLAC linac. At present, the old PEP tunnel has been cleared and installation of the high energy ring has started