Recent progress on the development of a multiple-beam klystron with 13% bandwidth

Summary form only given. We present recent progress on the development of an 18-beam multiple-beam klystron (MBK). The principal performance goals for this device include a peak rf output power of > 500 kW, an instantaneous bandwidth of 13% (1- dB), and high duty operation up to 2.5%. The detailed designs of the 18-beam electron gun and 7-cavity circuit are described in [K.T. Nguyen et. al., 2005] and [K.T. Nguyen et al., 2009], respectively. Experimental measurements of the resonant frequencies and Q´s of the individual cavities comprising the circuit will be compared with 3D electromagnetics simulations using HFSS (Ansoft Corp.) and Analyst (STAAR). Final assembly of the gun and circuit is planned for April 2009 with hot-testing of the device to follow immediately. We will present comparisons of the experimentally measured voltage-current characteristics of the electron gun with 3D particle simulations using MICHELLE [J.J. Petillo, 2002], and, as available, results of high power rf performance tests.