Matthew Colin Thompson, Hristo Badakov, James Rosenzweig, Gil Travish, Rodney Yoder (UCLA, Los Angeles, California), Mark Hogan, Rasmus Ischebeck, Robert Siemann, Dieter Walz (SLAC, Menlo Park, California), Patric Muggli (USC, Los Angeles, California)
An experiment is planned to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range. This new UCLA/SLAC collaboration will take advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., sz = 20 µm at Q = 3 nC). The electron beam will be focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 µm / OD = 325 µm and ID = 100 µm / OD = 325 µm. The pulse length of the electron beam will be varied in order to alter the accelerating gradient and probe the breakdown threshold of the dielectric structures. In addition to breakdown studies, we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain information about the strength of the accelerating fields. Status and progress on the experiment are reported.