• M. Mostajeran, M. Lamehi Rachti
  IPM, Tehran

Superconducting RF cavities have been used in modern accelerators. SRF cavities have the limitation on maximum RF voltage and maximum delivered RF power. The major limitation comes from Multipacting in the cavity and waveguide. To design a Multipacting-free RF structure, numerical tracing calculations are required. Here, Monte-Carlo method within a plane parallel model is employed using a wide range of parameters. For more accurate predictions, a long history of electron trajectories between two parallel plats is investigated. Simulations give us fast convergence when we are far from the avalanche threshold. However it is very difficult to get such convergence when we are close to the avalanche threshold. In the present work, we demonstrate how we can cope with this difficulty.