Curvilinear-axis focusing and aberration theory of wide electron beams for combined immersion magnetic-electrostatic lens systems

Abstract

Abstract Curvilinear-axis Gaussian electron optical properties and aberration characteristics of wide electron beams for combined immersion magnetic-electrostatic lenses are studied. Based on general wide beam and curvilinear-axis theory, paraxial trajectory equations in local orthogonal coordinates are obtained, and all of the second-order curvilinear-axis aberration coefficients are derived using a symbolic manipulation software Mathematica. The present paper lays a theoretical groundwork for further studies on curvilinear-axis focusing and aberration theory for the combined immersion magnetic-electrostatic lenses.