Electron Multipactor Code for High-power Rf Devices

We have developed an integrated software system, TrakRF, to model electromagnetic fields and charged particle orbits in high-power RF devices. Our primary application is simulation of electron multipactoring near RF vacuum windows for the APT (Accelerator Production of Tritium) Program. In this paper we describe features of the codes and initial multipactor calculations for superconducting cavity arrays. The finite-element frequency-domain solver can determine resonant modes in cavities and waveguides. TrakRF directly determines power dissipation and phase shifts in lossy materials. In addition, the program handles scattered waves in open structures with free-space boundaries based on matched termination layers. TrakRF has advanced particle tracking capabilities to investigate a variety of innovative window designs. The program can simultaneously apply three independent solutions for electrostatic, magnetostatic and RF fields. The finiteelement methods allow an accurate representation of electron collisions with surfaces.