COMPUTER-SIMULATION OF SINGLE-ION TRAJECTORIES IN PAUL-TYPE ION TRAPS

The computer simulation of single-ion trajectories using a number of c omputer programs is described together with associated theory. The pro grams permit calculation of ion trajectories while the ion is subjecte d to collisions with buffer gas of variable pressure, resonance excita tion in any of three modes, and static or ramped DC and radiofrequency levels. Initially, the programs were designed for the calculation of ion trajectories in a quadrupole ion trap. The programs now permit suc h calculations for ions confined in traps having electrodes shaped to include percentages of hexapole and octupole components in the electri c field as well as electrode surface geometries for which there is no closed-form expression. The Langevin collision theory is reviewed and a theoretical treatment of the multipole trap is presented.