This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.

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Achromatic-aplanatic lenses can be compound lenses consisting of a modified condenser lens and a coma-free objective lens. The modified condenser lens can be composed of conventional condenser lens and multi-element quadrupole–octopole corrector with special symmetric configurations. The quadrupole–octopole corrector can correct the spherical aberrations. The chromatic aberration can be removed or minimized by placing a crossed electric and magnetic quadrupole into the quadrupole–octopole corrector and by adjusting their electric and magnetic strengths properly. These compound lenses are therefore free of chromatic aberration, spherical aberration and off-axial coma.