Simulation of the pressure recovery time in a CLIC standard module

Vacuum pressure inside the CLIC accelerating structures (AS) is crucial for both beam and RF stability. Gas molecules released during RF breakdown must be evacuated from the cells of the AS before the arrival of the next train of particles. Due to its complex geometry, accurate analytical calculations are not viable. In this paper we introduce a calculation method based on the combination of analytical vacuum equations with Monte Carlo test particle simulations, implemented in a PSpice environment via the vacuum-electrical network analogy. Pressure recovery times are calculated for the main gas species released during a breakdown. The number and type of molecules used for the calculation is the result of measurements performed in the DC spark test system.