Results of the 30 GHz high power RF test on the "speed bump" and "TM02" structures

The demonstration of the 100 MV/m gradient of the accelerating structures at a breakdown rate of 10-7 pulse-1.m-1 is a key issue of the CLIC project. To demonstrate the feasibility of the latter, an important program is under way at X-band at CERN, KEK and SLAC. The 30 GHz test stand of the CTF3 complex offers also the possibility to test innovative idea concerning the breakdown physics. We present hereafter the results of the two experiments made on this test stand between summer 2008 and spring 2009. These experiments investigated the effects of lowering the group velocity on breakdown-induced damages (30CNSDsbCu) and on achievable gradient at a given breakdown rate (30CNSD2.0Cu).