N. Ouchi, E. Chishiro (JAERI), T. Tsukishima, K. Mukugi (MELCO)
The superconducting (SC) proton linac is proposed in the JAERI/KEK Joint Project for high-intensity proton accelerator in the energy region from 400 to 600MeV. The 600MeV proton beams are planned to inject into the 3GeV rapid cycling synchrotron (RCS) as well as the nuclear transmutation facility. The rf phase and amplitude stabilities in the cavities are required to be less than +/-1 deg. and +/-1%, respectively, for the injection to the RCS. In the pulsed operation of the SC cavities, dynamic Lorentz force detuning disturbs rf stability. In order to simulate the rf control, a model describing the dynamic Lorentz detuning, which is based on the structural modal analysis and the electromagnetic analysis, has been developed. Result of the model calculation was compared with the experimental results and good agreement was obtained. The rf simulation of the SC cavity was also performed using the model.
In the conventional pulsed rf operation, some mechanical vibration modes are excited by the pulsed Lorentz force. By adopting smooth rf excitation, the mechanical vibration was found to be much reduced. The new model for the dynamic Lorentz detuning and the results of the rf simulation will be presented.
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