High-power testing of 11.424-GHz dielectric-loaded accelerating structures

The design, construction, and bench testing of an X-band travelling-wave accelerating structure loaded with a permittivity=20 dielectric has been published recently by the Argonne Advanced Accelerator Group. We describe a new program to build a test accelerator using this structure. The accelerator will be powered using high-power 11.424-GHz radiation available at the Magnicon Facility at the Naval Research Lab. The magnicon is expected to provide up to 30 MW from each of two WR-90 output waveguide arms in pulses of up to 1-μs duration, permitting tests of the dielectric-loaded X-band device at gradients of ~40 MV/m. The use of higher power pulses (100-500 MW) eventually available at the output of an active pulse compressor driven by the magnicon will permit gradients in excess of 100 MV/m to be achieved