Tuesday, May 15, 2018
The Waves and Beams group at MIT has a tradition of pointing the output of our 1.5 MW, 110 GHz gyrotron at things to watch them burn. Putting this pastime to use, we have been most recently studying multipactor discharges on dielectric in high vacuum. Multipactor discharges are generally undesirable in high power microwave devices and RF accelerators, though, they have not been studied at frequencies above about 10 GHz. Experiments have been performed to set a variety of dielectric materials and geometries aglow with intense, 110 GHz incident radiation. Breakdown thresholds have been measured as a function of geometry and dielectric material parameters. Work is still underway to evaluate how well simple monte carlo models, developed to describe lower frequency discharges, extend to the millimeter wave regime.