A conceptual design study for a vacuum system for a possible compact high luminosity upgrade to CESR is presented. The vacuum chamber consists of an elliptical cross-section beam chamber connected to a pumping chamber by holes recessed in several channels in the beam chamber wall. Recessing the hole provides a decrease in the impedance of the beam chamber while still providing protection to the pumping chamber from RF fields generated by the beam. The beam chamber has a very compact cross-section compatible with two-in-one quadrupole magnets and inexpensive compact dipole magnets. Pumping will be provided by a combination of nonevaporable getter (NEG) and ion pumps. Calculations were carried out of the impedance and loss factor of the chamber as well as transmission of RF field power through the slots and the conductance of the pumping slots. We have also calculated the linear synchrotron radiation power density and the pressure profile and beam-gas lifetime for this chamber and pump configuration. We consider the time between necessary NEG pump reactivations and the total capacity of the pumps.

A conceptual design for a vacuum chamber for a compact high luminosity upgrade to CESR is presented. The vacuum chamber consists of a circular beam chamber connected to a pumping chamber by holes recessed in several channels in the beam chamber wall. Recessing the holes provides a decrease in the impedance of the chamber while still providing protection to the vacuum chamber from RF(TE) fields generated by the beam. A vacuum chamber with recessed holes was previously developed for the High-Energy Ring at PEP-II [1]. Calculations were carried out of the impedance and loss factor of the chamber as well as transmission of RF(TE) power through the holes and the conductance of the pumping holes. The pump chamber has a very compact cross-section compatible with two-in-one quadrupole magnets and inexpensive compact dipole magnets.

We report results of calculations and measurements relating RF phase noise to longitudinal motion of a stored beam. Treating the beam as a noise driven coupled oscillator system, we have made calculations to determine what coupled bunch synchrotron oscillation amplitudes result from RF phase noise. Measurements have also been carried out at CESR of phase noise in the RF system and coupled bunch synchrotron oscillation amplitudes. We also consider the impact of this noise on the dynamic range of a longitudinal feedback system.

Using the silicon strip detector of the CLEO experiment operating at the Cornell Electron-Positron Storage Ring (CESR), we have observed that the horizontal size of the luminous region decreases in the presence of the beam-beam interaction from what is expected without the beam-beam interaction. The dependence on the bunch current agrees with the prediction of the dynamic beta effect. This is the first direct observation of the effect.