  Dielectric loaded structures are promising candidates for use in the
structure wakefield acceleration (SWFA) technique, for both the collinear
wakefield and the two-beam acceleration (CWA and TBA respectively) approaches,
due to their low fabrication cost, low rf losses, and the potential to
withstand high gradient. A short pulse (<=20 ns) TBA program is under
development at the Argonne Wakefield Accelerator (AWA) facility where
dielectric loaded structures are being used for both the power
extractor/transfer structure (PETS) and the accelerator. In this study, an
X-band 11.7 GHz dielectric PETS was developed and tested at the AWA facility to
demonstrate high power wakefield generation. The PETS was driven by a train of
eight electron bunches separated by 769.2 ps (9 times of the X-band rf period)
in order to achieve coherent wakefield superposition. A total train charge of
360 nC was passed through the PETS structure to generate ~200 MW, ~3 ns
flat-top rf pulses without rf breakdown. A future experiment is being planned
to increase the generated rf power to approximately ~1 GW by optimizing the
structure design and improving the drive beam quality.
