Paul Trap

A paul trap (quadrupole ion trap) is a type of ion trap that confines charged particles using DC and RF electric fields (not magnetic fields like in a Penning Trap).

SIMION Specific

SIMION examples include

  • SIMION Example: quad - RF linear quadrupole mass filter
  • SIMION Example: trap - RF ion trap
  • SIMION Example: octupole - RF linear octupole trap, which is a variant of the RF linear quadrupole trap but with eight electrodes for an octupole field
  • The examples\geometry folder in SIMION 8.0 contains GEM files for a few quadrupole and ion trap geometries.
  • Time-Dependent Field - general notes on RF fields in SIMION
  • Session 6 “Quadrupole Principles” and Session 7 “Ion Trap Principles” in the Short ASMS Course (courses\short folder in the SIMION 8.0 program directory and also included in SIMION 7.0).
  • About 50 pages of notes on linear ion trap simulations soon plan to be added to Virtual Device , covering analytical theory, SIMION tests, gas flow model, and trap capacity. As of Aug 2011 drafts are in progress.



SIMION Modify geometry screen showing 3D quadrupole ion trap.


3D quadrupole ion trap, with adjustable variables.


3D quadrupole ion trap, potential energy view.


3D quadrupole ion trap, particle motion (showing heavy ions in largest shell).

Papers on using SIMION with Paul Traps

Papers on simulating Paul and multipole traps with SIMION would be too numerous to list here (hundreds or maybe thousands), but let’s add a few. If you have a paper, let us know to add it to this list. Search Google Scholar for more.

  • Collision models in ion traps: See Ion-Gas Collisions.
  • Linear multipole rods and 3D quad
  • Cylindrical
    • AustinCruz2006. Austin, Daniel E. Cruz, Dolores, Blain, Matthew G. Simulations of ion trapping in a micrometer-sized cylindrical ion trap. Journal of the American Society for Mass Spectrometry. volume 17, issue 3, year 2006, pages 430-441 doi:10.1016/j.jasms.2005.11.020 - “We have performed detailed SIMION simulations of ion behavior in micrometer-sized cylindrical ion traps (r0 = 1 um).”
  • Toroidal
    • YuTang2016. Yu, Quan. Tang, Lijuan. Ni, Kai. Qian, Xiang. Wang, Xiaohao. Computer Simulations of a new toroidal-cylindrical ion trap mass analyzer Rapid Communications in Mass Spectrometry, year 2016 doi:10.1002/rcm.7713 – “toroidal-cylindrical ion trap (TCIT) based on a compact dual ion trap system that comprises an outer toroidal ion trap (T-trap) and an inner cylindrical ion trap (CIT)” “The TCIT is studied by using a simulated mass spectrometer platform that is mainly based on SIMION modeling and extensive data processing. This platform combines different functions, such as simulation of ion motion and field calculations, as well as acquisition of a simulated mass spectrum.”
    • Cylindrical Toroidal Ion Trap Mass Spectrometer Daniel Austin and Nick Taylor, Brigham Young University. background overview, pictures, and SIMION simulations. Workshop on Harsh-Environment Mass Spectromet, 8th (2011).
  • 2D Linear ion traps Wikipedia:Linear_ion_trap
    • SchwartzSenko2002. Schwartz, Jae C. Senko, Michael W. Syka, John E. P. (Thermo) A two-dimensional quadrupole ion trap mass spectrometer Journal of the American Society for Mass Spectrometry. volume 13, issue 6, year 2002, pages 659-669 doi:10.1016/S1044-0305(02)00384-7 “The use of a linear or two-dimensional (2-D) quadrupole ion trap as a high performance massspectrometer is demonstrated.” (highly cited) – with SIMION simulations
  • Rectilinear
    • GangYi2015. Gang, Huang. Yi, Chen. Fei, Tang. Li-Tao, Liu. Xiaohao, Wang. Optimization and simulation of MEMS rectilinear ion trap AIP Advances, volume 5, issue 4, year 2015, pages 041303 doi:10.1063/1.4902889 “SIMION software was used to simulate the MEMS rectilinear ion trap with different sizes and different radio-frequency signals.”
  • Other - Halo, Resistive
    • Halo Ion Trap Mass Spectrometry: Design, Instrumentation, and Performance Miao Wang. Thesis. Brigham Young University 2010-11-02 - with SIMION simulations. “The halo IT was also based on toroidal trapping geometry and microfabrication technology, consisting of two parallel ceramic plates, the facing surfaces of which were imprinted with sets of concentric ring electrodes. Unlike conventional ITs, in which hyperbolic metal electrodes establish equipotential boundary conditions, electric fields in the halo IT were established by applying different RF potentials to each ring.”
    • AustinPeng2008. Austin, D. Peng, Y. Hansen, B. Miller, I. Rockwood, A. Hawkins, A. Tolley, S. Novel Ion Traps Using Planar Resistive Electrodes: Implications for Miniaturized Mass Analyzers Journal of the American Society for Mass Spectrometry. volume 19, issue 10, year 2008, pages 1435-1441 doi:10.1016/j.jasms.2008.03.019 - with SIMION simulations. “ion traps in which the electrodes consist of two ceramic discs, the facing surfaces of which are lithographically imprinted with sets of concentric metal rings and overlaid with a resistive material. A radial potential function can be applied to the resistive material such that the potential between the plates is quadrupolar, and ions are trapped between the plates.”
  • Other - Wire
  • More, Uncategorized
    • 10.1016/j.jasms.2008.05.022SalazarMasujima2008. Salazar, G. Masujima, T. Computer Simulation of the Gap-Tripole Ion Trap with Linear Injection, 3D Ion Accumulation, and Versatile Packet Ejection Journal of the American Society for Mass Spectrometry, volume 19, issue 9, year 2008, pages 1367-1374 doi:10.1016/j.jasms.2008.05.022 “The behavior of a completely new ion trap is shown with SIMION 7.0 simulations. The simulated trap, which was a mix of a linear and a 3D trap, was made by axially setting two ion guides with a gap between them.”