Increased Intensity Performance of the Brookhaven

With the advent of Hinjection into thfSBrookhaven AGS, circulating beams of up to 3 x 10 protons at 200 MeV have'been obtained. Rf 2.2 x 1013 and acceleration of 1.73 x 10 fspture of up to the transition energy (8 GeV) and 1.64 x 1013 to full energy (' 29 GeV) has been achieved. This represents a 50% increase over the best performance obtained with H+ injection. The increase in circulation beam current is obtained without filling the horizontal aperture. This allows the rf capture process to utilize a larger longitudinal phase space area (" 1 eV set/bunch vs < 0.6 eV set with H+ operation). The resulting reductTon in relative longitudinal density partially offsets the increase in space charge effects at higher currents. In oF!er to make the capture process independent of injected beam current, a dynamic beam loading compensation loop was installed bn the AGS rf system. This is the only addition to the synchrotron itself that was required to reach the new intensity records. A discussion of injection, the rf capture process, and space charge effects is presented.