Second order spatial focusing of charged particle beams in fringing fields of an electrostatic sector spherical deflector with a large interelectrode gap

In the present work a possibility of achieving in sector spherical energy analyzers with a large interelectrode gap of the spatial focusing of higher than first order was studied by means of computer simulation. based on the analysis of influence on spatial focusing of fringing field effects the possibility of designing of spherical deflector configurations providing the second order angular focusing is shown. At 5 degree angular acceptance of the particles beam, originating from the point source, the energy resolution may be increased up to 0.1%. The proposed configurations possess the characteristics of the einzel lens with curvilinear axis and may be easy transformed into new optical elements with high quality of the angular focusing combined with high energy dispersion.