xmpl3d05, 5th 'example' data file for CPO3D

Quadrupole filter with oscillating field.

Superseded by xmpl3d95, which uses the option for users equations.


The exact electrode shapes for the ideal quadrupole field are simulated in this example by a mixture of 'cylindrical' rectangles (that is, rectangles that are part of a cylindrical surface) and flat rectangles. The particles are singly charged nitrogen molecular ions.


The following data were obtained when the memory and speed of PC's was much more limited than at present, so the available number of segments was small and the requested inaccuracies were fairly high to give a quick demonstration.


The left and right electrodes have the voltage V and the shape given by


while the top and bottom electrodes have the voltage -V and the shape given by


so the potential distribution is give by


In this example the voltage V is given the time dependence


where v0=0.6, v1=7.0, tau=0.0006ms.

For technical reasons the curvature information has to be entered each time -see note on insribing and note on curvature. The density of segments is highest in the vicinity of the beam.

The particles are singly charged nitrogen molecular ions.