Three-dimensional simulation of charged particle beam trajectories in radio frequency electric field of a quadrupole mass spectrometer

A numerical simulation method for ion trajectory analysis in a three-dimensional radio frequency electric field is developed. The present method is based on the boundary element method (BEM) to calculate the electric field and the high-order Runge-Kutta method (Shanks method) to trace ion trajectories with high numerical accuracy. In order to reduce computational memory and time while maintaining computational accuracy, the interpolative functions of the BEM and the integration method of the equation of ion motion are discussed in detail. ajectories at the entrance part of the quadrupole field are successfully simulated using the proposed method. The influence of the ion beam focusing position on the transmission efficiency at the entrance part is evaluated with the results.