The Simulating Of Ion Optical System Based On Finite-element Method And The Optimization Of Parameters And Structures

Cluster Beam System,consisting of magnetron sputtering,ion optic,and Time-of-Flight Mass Selector,can produce high quality ligand-free size-controlled clusters.However,the main weakness of this system is the limitation of productivity.As ion optic is count for one of the main reason of the beam loss,it needs optimization.In this article,we simulate the potential distribution and particle trajectories by finite-element method(FEM),optimize the voltage para-meters of the ion optic to get the highest passing rate,and compare the result with experiment.The simulation result can reflect the mechanics of ion optics in a good extent and can narrow the tuning range.This plays an effectively auxiliary role in the experiment.Meanwhile,we try to optimize the structure of ion optic by FEM simulation in two ways.We calculate the relation between the passing rate and the width of ion optic system,and analyze the mechanics by calculating the particle loss in the exit of electrostatic field lenses and the mass selector.We also calculate the relation between the passing rate and the radius of the exit aperture of the electrostatic field lenses,and analyze the effect of the radius change to other parts of the ion optic system.This work provides an effective theory and data support of optimizing ion optic system.