SECOND ORDER SPATIAL FOCUSING OF
CHARGED PARTICLE BEAMS IN FRINGING FIELDS OF
AN ELECTROSTATIC SECTOR SPHERICAL DEFLECTOR
WITH A LARGE INTERELECTRODE GAP
V. D. Belov
Institute for Analytical Instrumentation RAS, Saint-Petersburg
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.