Author: Arai, S.
Paper Title Page
TUPB095 Design of Coupler for Direct Coupled Amplifier to Drift Tube Linac Cavities of the Injector RILAC2 for RIKEN RI Beam Factory 684
  • K. Suda, S. Arai, Y. Chiba, O. Kamigaito, M. Kase, H. Okuno, N. Sakamoto, Y. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  A new linac RILAC2 was constructed at RIKEN RI Beam Factory as an injector for very heavy ions such as uranium and xenon of a high mass to charge ratio m/q  ∼  7, but high intensity ions can be extracted from an ion source. Three drift tube linac cavities, operate in continuous wave mode at 36.5 MHz, have been designed and built. In order to reduce an installation area, and to save a construction cost, we adopted a direct coupling method for a power amplifier without using a long transmission line. A complicated design procedure was performed in order to take into account a change of resonant frequency of the cavity caused by a capacitance of a power tube used in the amplifier. A design of the coupler, as well as the cavity was performed using a three-dimensional electromagnetic calculation code, CST Microwave Studio (MWS). The measured input impedance seen from the amplifier (700 – 1100 Ω) was reproduced well by the calculation of MWS. Also, in order to examine MWS, a case of a coupling with 50 Ω were calculated. The coupling conditions obtained by MWS were compared with the measurement and a calculation with a lumped circuit model.