High Charge Picosecond Pulses with a Double Gap Subharmonic Buncher

A new improved bunching system was designed in 1976 and installed in 1981 in the Argonne Electron Linac to replace the one installed in 1972. In the new bunching system, a spiral loaded double gap 12th subharmonic buncher is replacing the previous single gap 6th subharmonic buncher and a one wavelength fundamental frequency traveling wave prebuncher has replaced the previous two wavelength prebuncher. Individual pulses of picosecond (25 to 36) duration and up to 40 ¿ Coulomb in charge, with ¿E/E < ± 0.5% at FWHM over the energy range of 4 to 22 MeV, and a repetition rate from one to 1000 p psec are available to the experimenter on a routine basis. The design and the microwave properties of the cavity are discussed along with the general design of the injector and the results achieved.