Development of a 26 GHz RF Power Extractor

The design trend in normal-conducting high gradient accelerating structures is to move toward higher frequencies. The same is true for other microwave applications like radar or communications. This project will develop a new high power radio frequency (RF) source that covers the frequency spectrum from 20-30 GHz. It will evaluate a prototype power extraction structure incorporating advanced low loss dielectric materials to produce 26 GHz RF when energized by a high current electron bunch train. The device will be evaluated experimentally using the beam facilities at Argonne National Laboratory. The Phase I project fabricated a prototype 26 GHz dielectric loaded structure that was cold tested to verify efficient power transfer from the structure. Numerical simulations of beam interaction with the structure were carried out. The Phase II project will test the structure in a series of experiments at the Argonne Wakefield Accelerator facility. Rf output power levels will be measured. Loss of efficiency caused by the beam breakup instability will be characterized and new techniques for its mitigation will be tested. Commercial Applications and other Benefits as described by the awardee: The new RF power source will permit construction of advanced, efficient linear accelerators for high energy physics research. The availability of a high power 26 GHz source will be useful for radar systems, remote sensing, and communications.