MECH: Design and Mechanical Tolerancing of Electron Lenses
The MECH software package computes the properties of electron lenses, including the effects of mechanical defects in lens construction and alignment, such as misalignments, tilts and ellipticities of the individual electrodes or polepieces. Perturbation field distributions due to small mechanical defects in construction are computed by a perturbation method, based on Sturrock's principle. The effects of these asymmetry fields on the optical properties, i.e. the beam displacement and coma due to small misalignments and tilts, and the astigmatism caused by electrode ellipticities, are then computed. The values of the asymmetry aberrations caused by the mechanical defects can be used to specify suitable tolerances for the construction and alignment of electrostatic lenses. There are three components to the package: EMECH, for electrostatic lenses; MMECH, for magnetic lenses; and CMECH for combined field lenses.
If you are interested in the MECH package, please contact us at info@electronoptica.com.