Particle-in-cell plasma simulation code for ion trap mass spectrometer

Summary form only given, as follows. We developed a particle-in-cell (PIC) finite difference simulation code as a numerical tool for designing quadrupole ion trap mass spectrometers. The code is capable of tracing the motion of various heavy ion species in the background of a light neutral gas, like He, in a complicated quadrupole trap geometry. Moreover, the code can describe the ions nonlinear dynamic under multi-frequency and polarity rf signals and in particular under the filtered noise field (FNF). In this mode of operation a low voltage rf noise with a specific narrow band removed by a notch filter is injected between the end caps of the ion trap together with the high voltage rf signal across the trap. This results in an enhancement of the mass spectrometer sensitivity by selecting and concentrating a specific ion species. Various modes of operation as well as various geometries of the ion trap will be presented and compared with experimental results.