Although in the past the D to A line was well tuned, through the course of years of operations it has not kept up with changes in the Debuncher and Accumulator. The beam is now steered well off center in SEM's 806 and 807, and is possibly scraping in TQ5. In addition, there is some evidence that the beta functions are not matched, causing emmitance blowup of the beam. As the cycle time of the main ring has decreased these limitations have become a significant limitation to the stacking rate.

The multi-ampere currents required for high luminosity operation of an asymmetric B factory leads to extremely stressing requirements on a vacuum system suitable for maintaining long beam-gas lifetimes and acceptable background levels in the detector. We present the design for a Cu alloy vacuum chamber and its associated pumping system for the 9 GeV electron storage ring of the proposed B factory based on PEP. The excellent thermal and photo-desorption properties of Cu allows handling the high proton flux in a conventional, single chamber design with distributed ion pumps. The x-ray opacity of the Cu is sufficiently high that no additional lead shielding is necessary to protect the dipoles from the intense synchrotron radiation generated by the beam. The design allows chamber commissioning in <500 hr of operation. 5 refs., 3 figs., 2 tabs.