Spectrometer chopper for AHF and SSC low-energy transports

The study of a possible chopping system for the Advanced Hadron Facility (AHF) and the Superconducting Super Collider (SSC) is presented. A 200 MHz RFQ (radio-frequency quadrupole accelerator) may be preferable to lower-frequency structures for the injection linacs of the AHF and SSC. To achieve a pulse frequency of 50 MHz, a chopper must be developed to eliminate three out of four bunches at the tenth of a percent level. Conventional choppers suffer from risetime limitations due to the finite separation of the deflecting plates. One alternative is a spectrometer chopper which modulates the energy of each bunch and then separates the bunches with a spectrometer transport. Initial design studies are presented for this concept