ILC RF system R&D

The ILC Linac Group at SLAC is actively pursuing a broad range of R&D to improve the reliability and reduce the cost of the L-band (1.3 GHz) rf system. Current activities include the development of a Marx-style modulator and a 10 MW sheet-beam klystron, construction of an rf distribution system with adjustable power tapoffs and custom hybrids, tests of cavity coupler components to understand rf processing limitations, simulations of multipacting in the couplers and optimization of the cavity fill parameters for operation with a large spread of sustainable cavity gradients. Also, a prototype positron capture cavity is being developed for the ILC injectors. This paper surveys the results from the past year and notes related L-band R&D at other labs, in particular, that at DESY for the XFEL project.