SBIR-STTR Award

The next generation nuclear physics accelerator facility, the Electron Ion Collider EIC), will accelerate and collide spin polarized electrons and ions focused to an unprecedented density at their point of collision. To achieve the desired electron/ion density at the focal point, the technique of electron cooling will be applied. In this technique, the ion beam is temporarily accompanied by a high current electron beam in what is called the “cooling section”. Jlab has designed a multi-pass energy recovery cooler where the electron beam is redirected back to the entrance of the cooling section for multiple passes to increase efficiency. This scheme requires beam-switching kickers to extract and inject the electron beam with speed and precision that is beyond the state of the art. In response to this urgent need, Electrodynamic and Jlab have been working together on a unique solution, fast multi-harmonic kickers. Multi-harmonic kickers use cavities with multiple harmonic modes that are driven by computer controlled multi-harmonic sources to produce fast kicking pulses. Two designs are being simultaneously developed, one for transverse kicking, and the other for longitudinal boosting with magnetic separation. Both development efforts are finally within reach of beam line evaluation; this is the goal of this SBIR. The purpose of this SBIR is to experimentally evaluate both potential fast kicking solutions on Jlabs UITF beamline Upgrade Injector Test Facility). Both of these solutions will deliver intra-bunch fast kicks by simultaneously superimposing multiple RF frequencies within a harmonic cavity. Electrodynamic and Jlab have established a solid foundation for this goal. At the time of this submission, both cavity designs have been physically prototyped, both have had computer controlled multi-harmonic sources developed for them, and vacuum compatible prototypes are planned to be constructed during the Phase I period. Remaining is the development of high power RF amplifiers for each harmonic and high power harmonic power combiners to deliver the kicking pulse. Phase I will develop high power amplifiers and harmonic combiners to drive the kickers, and will support the fabrication and construction of vacuum compatible kicker cavities. The Phase II project will result in the experimental evaluation of both these technologies at Jlab’s UITF.

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.