Quasi-Optical Millimeter-Wave Accelerating Structure

65565 Lasers play an important role in research seeking new mechanisms for high-gradient electron acceleration. This project will develop technology to produce a 90 MeV gyrating electron beam with particles advancing in phase at the laser frequency, executing one cycle each 35 fs. A beam stop with an off-axis channel will transmit a short beam pulse every optical cycle, thereby producing a train of about 30 one pC microbunches for each laser pulse. These bunches can be focused to a few microns width in one transverse direction using a quadrupole and injected into a planar dielectric-lined waveguide where cumulative buildup of wakefields can lead to acceleration gradients approaching 1 GV/m. In Phase I, a practical beam optics arrangement will be devised to direct a gyrating, finite-emittance beam from a laser-based vacuum accelerator, through a beam stop with an off-axis channel, through a quadrupole, and into a planar dielectric-lined waveguide. The arrangement will be optimized for maximum microbunch charge and minimum transverse width in the dielectric-lined waveguide. Commercial Applications And Other Benefits as described by the awardee: Thousands of inexpensive micro-scale wake field generators could be required for a future collider. Micron-scale electron bunches can also be used in plasma-based accelerators and in the generation of intense bursts of sub-harmonic radiation, required in many areas of research.