Basics

The correction of spherical (C_s) and chromatic (C_c) aberrations cannot be carried out with rotationally symmetric electron lenses (Scherzer, Z. Phys. 101 (1936) 593 ). Therefore, multipole elements have to be used for the correction.

• Our C_c/C_s-Corrector uses electric/magnetic quadrupoles and octupoles for correction as invented by Rose (Optik 33 (1971) 1).
• The C_s-Correctors use hexapoles in an arrangement with additional round lenses (Rose, Optik 85 (1990) 19).
• We have developed a purely electrostatic C_c/C_s-Corrector (Weißbäcker & Rose, 2001) suitable for ion optical applications.

The principal questions about electron microscopy are answered here:

• Who invented the electron microscope?
• What's the advantage of using electron microscopes instead of light microscopes?
• How does an electron microscope work?
• Which types of electron microscopes exist?
• What does the famous "Scherzer Theorem" imply?
• How can aberrations be corrected?
• How does a typical corrector look like and how does it work?
• How is the information limit defined?
• Which analytical techniques can be applied in an electron microscope?