Barrier Buckets in the CERN SPS

The use of barrier buckets to modify the azimuthal distribution of a beam in a circular accelerator has been described and demonstrated in several machines. Barrier buckets could become interesting for future modes of operation in the CERN SPS. Up to now the specially designed RF cavities used for this purpose have been very wide-band, capable of producing a single sine-wave. The existing 200 MHz Travelling Wave cavities in the SPS are not as wide-band but nonetheless have rise-times that are small compared with the revolution period. The possibility of using these cavities to provide "thick" barriers has been studied theoretically and experimentally in the SPS.