A Unified Representation of Magnetic Electron Lens Properties

This is the authors' abstract. We don't add key points for this paper.

It is shown that the focal lengths of all known iron shrouded magnetic electron lenses lie between two fairly close `limit-curves', if f is measured in the unit S+D for symmetrical or S+R 1 + R 2 for asymmetrical lenses of bore radii R 1 and R 2 and gap length S, f being plotted as function of ( NI ) 2 / V r . The lenses of the more usual S/D ratios (0.5 less-than-or-eq, slant S/D less-than-or-eq, slant 2) lie very close to the lower `limit-curve', i.e. all these lenses can be represented by a single focal length curve. A similar representation can be given for the other lens constants.