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 tap- offs 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.