xmpl3d42, 4-fold deflector, 'staggered' split-disc edgeways plates

Also desribed as the 4-fold 'edge-wise' deflector.

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’, embodied in the present file, 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).

This data file is based on xmpl3d35.  The pairs of plates have the same configurations as in xmpl3d35, but the +/-x and +/-y pairs have different axial positions, with an optimised gap of 3.0 between them in the axial direction.

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.