Author: Nakao, K.
Paper Title Page
MOPC156 Operation Test of Distributed RF System with Circulator-less Waveguide Distribution in S1-Global Project at STF/KEK 448
  • T. Matsumoto, M. Akemoto, D.A. Arakawa, S. Fukuda, H. Honma, E. Kako, H. Katagiri, S. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida
    KEK, Ibaraki, Japan
  Distributed RF System (DRFS) is one candidate for a single main linac tunnel design of International International Linear Collider (ILC). In the DRFS, more than ten 800-kW klystrons having a modulating anode are operated by a common DC power and a modulation anode modulator. Each klystron feeds its power into two superconducting cavities and its waveguide distribution system is configured without circulators. This DRFS consists of four SC cavities, two klystrons and a modulator was demonstrated in S1-Global project. The results of circulator-less operation in the DRFS will be reported.  
THPC142 Burst Pulse Superimposed Electron Beam Acceleration in LEBRA FEL Linac 3218
  • T. Tanaka, K. Hayakawa, Y. Hayakawa, M. Inagaki, K. Nakao, K. Nogami, N. Sato
    LEBRA, Funabashi, Japan
  • S. Aizawa, Y. Arisumi, K. Shinohara
    Nihon Koshuha Co. Ltd, Yokohama, Japan
  • I. Sato
    Nihon University, Advanced Research Institute for the Sciences and Humanities, Funabashi, Japan
  The electron beam for free electron laser (FEL) at the Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University had been extracted from a conventional DC triode electron gun system. In conjunction with the renewal of the gun high voltage terminal a Kentech high-speed grid pulser was installed in addition to the conventional grid pulser. The 89.25MHz sine wave frequency-divided from the 2856MHz accelerating RF has been applied to the high-speed grid pulser, generating 64 or 128 frequency-divided grid pulses synchronous with the round-trip time in the FEL optical resonator. The high-speed grid pulses have been applied to the EIMAC Y646B cathode simultaneously with the conventional macropulse through the pulse coupling strip-line circuit; the resultant beam has been the short pulse beam superimposed on the macropulse beam. By reducing the macropulse voltage, only the train of the burst beam with 0.6ns width has been extracted. The peak burst beam current roughly 6 times higher than the conventional macropulse beam has been obtained with the Farady cup at the end of the FEL beamline. The FEL lasing experiment with the burst beam is underway.