The active filter voltage ripple correction system of the Brookhaven AGS Main Magnet Power Supply

The Brookhaven AGS is a strong focusing accelerator which is used to accelerate protons and various heavy ion species to an equivalent proton energy of 29 GeV. Since the late 1960's it has been serving high energy physics (HEP-proton beam) users of both slow and fast extracted beams. Since the late 1980's slowly extracted heavy ion beams have been added for fixed target physics experiments (HIP). Beginning in 1996 fast extracted beams will be commissioned in preparation for injection into the RHIC accelerators. This paper, and a companion paper, describe the improvements to the Main Magnet Power Supply (MMPS) so that it enables a more flexible operation of the AGS, enhances its reliability, and also improves the MMPS's ultimate performance specifications. One of the major areas for the latter is the fixed target program operating off the AGS slow extracted beam lines. The active filter, by improving the MMPS output ripple, is instrumental in the improvement of the ultimate duty factor of the extraction beam spill.