PEP-II Asymmetric {ital B} Factory: R and D Results

PEP-II, a 9 GeV x 3.1 GeV electron positron collider with a design luminosity of 3 x 10{sup 33} cm{sup -2}s{sup -1}, has been proposed by SLAC, LBL and LLNL as an upgrade of the existing PEP collider. An aggressive R&D program is now under way to validate the design choices. Progress and plans are described for the prototype low- and high-power RF cavities and the prototype 476-MHz, 500-kW klystron, and advances in the bunch-by-bunch longitudinal feedback system are indicated. Gas desorption tests (performed at BNL) on typical vacuum chamber materials are discussed. Progress in designing the IR is outlined and, finally, the tunnel mock-up is described