RF hardware development work for the CLIC drive beam

It is foreseen that the transfer structures (CTS) of the drive linac will produce 40 MW, 11.4 ns, 30 GHz RF power pulses for acceleration purposes in the CLIC main linac. Extensive model work, using the beam simulating wire method, has been undertaken in order to study the properties of the CTS with oversize models working at 8.6 GHz. At present a real size Cu 30 GHz CTS is under construction for beam tests in the CLIC Test Facility. A second Cu structure is in preparation for power testing with an MIT 33 GHz FEL power source. Further work is the development of power phase shifters and, inspired by the SLAC SLED-II studies, investigation into the use of longer RF pulses (than 11.4 ns) from the CTS (by a factor 3-4) combined with pulse compression. With longer RF pulses the drive beam bunchlet generation should become easier since the total drive beam charge of 7.04 μC would be distributed over more bunchlets