Advances in beam optics analyzer

Summary form only given. Calabazas Creek Research (CCR) is continuing development of Beam Optics Analyzer (BOA), an adaptive mesh, finite element, charged particle trajectory modeling tool for designing 3D electron devices. Several analysis types are available, including electrostatics, beam optics, electrostatic Particle-In-Cell, nonlinear magnetostatics, inhomogeneous Helmholtz and nonlinear heat transfer including radiation.This paper will present recent enhancements to simulate a 100 kW, gridded magnetron, determine penetration depth of back scattered electrons in study surface coatings, and model permanent magnets to curve the electron beam in a multiple beam klystron. We will describe the method used to push particles in RF fields, including adaptive time stepping, elastic backscattering analysis in combination with Monte Carlo method to determine the electron penetration depth, and magnetostatic analysis of permanent magnets. Using leap frog method, in combination with adaptive time stepping, circular symmetry and periodic boundary conditions, BOA efficiently tracks particles in a gridded magnetron over several RF cycles. The RF fields are imported from either VSim or HFSS. We will discuss the time integration to obtain the average and RMS currents and surface power density to determine the effectiveness of a shadow grid in the magnetron. We will briefly describe the Monte Carlo method based on the Markov process. We will provide the formulation based on Rutherford scattering and Bethe´s stopping power formula to calculate the penetration depths of electrons before backscattering. We will also outline the vector finite element formulation for magnetostatic solver with permanent magnets to compute the magnetic field for doubly converged electron beams. We will present results of the gridded magnetron simulation (more detailed information will be provided in another paper), backscattered electrons on different coating materials, and curved, double convergent - lectron beams focused by permanent magnets.