An energy spectrum compressor system (ESC) for the Amsterdam Pulse Stretcher (AmPS)

To obtain high-duty (90%) electron beams, the present 2%-d.f., 500-MeV linac (MEA) will be modified into a low-d.f. (0.1%) injector for the pulse stretcher ring presently under construction. The accelerator peak current has to be increased from 10 mA to 80 mA to obtain an average current of 65 μA from the pulse stretcher. The resulting increase of the energy spread from 0.3% to 1-2% requires the installation of an energy compression system (ESC) to match the 0.2% acceptance of the pulse stretcher. The ESC consists of four magnets followed by a short-filling time RF traveling wave accelerator structure. Considerations concerning required energy range, beam loading, phase errors, and current ripple which determine the longitude dispersion and the required RF power source are presented