Fast Multi-Harmonic Kickers

The beams produced in particle accelerators are typically a stream of particle bunches separated in time by hundreds of picoseconds to several nanoseconds. There is an acute need in this field to select individual particle bunches from within a beam and ”kick” them onto a different trajectory using pulsed electromagnetic fields. The time frames associated with these operations can be too brief for semiconductor switches that require several nanoseconds to turn on, and several nanoseconds to turn off. This SBIR project is investigating a new approach to create brief kicking pulses by superimposing harmonic radio waves within a harmonically resonant kicking cavity. Two types of fast multi-harmonic kicker cavities are being developed by our collaboration. One will produce transverse kicks at 86.6 MHz and one will produce longitudinal kicks at 499 MHz. The transverse kicker will directly influence the trajectory of bunches within the beam, and the longitudinal kicker will use magnetic separation of selectively boosted bunches. This ultimate goal of this SBIR is to experimentally evaluate both kicking solutions on a beamline. The Phase I project, and efforts at Jlab, have established a solid foundation for achieving this goal. A beamline compatible transverse cavity is currently being assembled, once complete; it is ready for beamline evaluation at the start of Phase II. This is because its high power harmonic driver, originally a Phase II goal, was completed in Phase I. Phase I also developed longitudinal kicker cavities, a high power harmonic combiner technology, and a new type of harmonic synthesizer. Phase II will begin with beamline testing of the 86.6 MHz transverse kicker.A vacuum compatible longitudinal kicker cavity and its high power harmonic driver will be constructed and also beamline tested during Phase II.This new kicking technology has immediate and future needs in particle acceleration, including at Fermilab’s Project X where protons could be sent to several experiments simultaneously, and at the LCLS at SLAC where fast beam switching kickers could be used to operate multiple wigglers at near CW repetition rates. The fast drivers under development are also compatible with existing and future stripline type kickers. Fast arbitrary waveform generators have applications in communications and radar.