2D cathode symmetry
CPO2DS can of course be used to simulate cathodes, but we caution its use when the ray starting energies are non-zero.
The reason for this is that rays which start with non-zero energies are non-meridional, which forces the CPO2DS program to use code borrowed from CPO3DS to trace the rays, which in turn greatly increases the computing time.
By converting your 2D data file to a 3D format, using conv2to3 and tidying up the result, you will be using 3 planes of reflection symmetry through the z axis (x=0, y=0, x=y) which effectivelly increases the number of segments by a factor of 8, giving a good reduction in computing times. You will also be able to see the rays better than is possible with CPO2DS.