APROXIMATE CALCULATION OF ABERRATIONS CAUSED BY TOLERANCES FOR FOBRICATION AND ALIGNMENT OF MAGNETIC LENSў S POLE PIECES

I. S. Makarowa

Research Institute for Electron and Ion Optics, Moscow, Russia

B. N. Vasichev, M. O. Zotova

Moscow Institute for Electronics and Mathematics (Technical University), Moscow, Russia

A. M. Filachev

State Scientific Center “Orion”, Moscow, Russia

The methods and program product for the calculation of magnetic electron lens aberration, caused by the unprecision of fabrication and alignment of pole pieces are presented. The influence of channel ellipticity and the relative shift of channel in pole pieces on aberration coefficients and radiuses of aberration circle of dispersion are estimated.