A quantitative calculation method of RF parameters for traveling wave accelerating structures

Equivalent circuit model of the coupled cavity chain has been widely used to analyze the properties of RF parameters of periodic accelerating structures. In this paper, the equivalent circuit model of disk-loaded waveguide traveling wave accelerating structure and its circuit equations are discussed and analyzed further. Based on analysis of relationship between the RF parameters of each cavity and the field distribution in the coupled cavity chain, a new method to calculate the frequency deviation of each cavity and the output coupling coefficient of the accelerating structure quantitatively is presented. This method is applied in a 10 MeV traveling wave accelerating structure tuning and results verify its correctness and effectiveness.