xmpl3d35, 2-fold deflector, flat 'edgeways' plates
Alternatives to the description 'edgeways plates' could be 'transverse flat plates' or 'edge-on plates'.
This is one of a set of 12 data files on electrostatic deflectors, listed in the comparison of deflectors.
The purpose of these files was to develop the ‘edgeways deflector’, see xmpl3d42, which was the subject of the publication number 42:
Edgeways electrostatic deflectors with reduced aberrations, by F H Read, Nucl. Instr. Meth. A427, 177-181 (1999).
The (unexpected) conclusion was that the 4-fold 'edgeways' deflector is much better than the conventional deflectors in current use (in 1999).
In the present data file the deflector plates are thin, flat plates that are transverse to the beam axis. The +x deflector plate is a 'clipped' section of a disc that has an inner radius of 3.5 and s centred on the axis x = -2.5. The minimum distance of the plate from the beam axis is therefore 1, as required. The -x deflector plate is a mirror image. The radius r has been optimised to give the best performance.
The rays start from a circle of radius 1 at z = -8 and converge to an axial point at z = 8.
The beam is deflected in the x direction. The deflection voltage is such that the principal ray has x = 0.5 at z = 8. Please refer to the data file itself for further information.
The program used to analyze the output data to deduce the aberration coefficients is called xmpl3d33_output in the programs list.
The results are summarised in the comparison of deflectors.