Booster main magnet power supply improvements for NASA Space Radiation Laboratory at BNL

The NASA Space Radiation Laboratoty (NSRL), constructed at Brookhaven National Laboratory, under contract from NASA, is a new experimental facility, taking advantage of heavy-ion beams ´from the Brookhaven Alternating Gradient Synchrotron (AGS) Booster accelerator, to study radiation effect on humans, for prolonged space missions beyond the protective terrestrial magnetosphere. This paper describes the modifications and operation of the Booster Main Magnet Power Supply (MMPS) for NSRL applications. The requirement is to run up to 1 sec flattops as high as 5000 Amps with 25 % duty cycle. The controls for the Main Magnet Power Supply were modified, including the Booster Main Magnet application program, to enable flattop operation with low ripple and spill control. An active filter (AF) consisting of a +/- 120 volts, +/-700 Amps power supply transformer coupled through a filter choke, in series with the Main Magnet voltage, was added to the system to enable further ripple reduction during the flattops. We will describe the spill servo system, designed to provide a uniform beam current, during the flattop. Results from system commissioning will be presented.