ABERRATION CORRECTOR AND ELECTRON MICROSCOPE WITH SUCH CORRECTOR

摘要

An aberration corrector (10) for an electron microscope includes a geometric aberration corrector (200) provided with a transfer lens system disposed between the optical systems for geometric aberration correction (210, 220), wherein the transfer lens system includes an optical system for chromatic aberration correction (100), the optical system for chromatic aberration correction (100) has a first portion (110a), a second portion (110b), and a third portion (110c) disposed along an optical axis, and each of the first portion (100a), the second portion (110b), and the third portion (110c) has a thickness in a direction along the optical axis and generates an electromagnetic field having two-fold symmetry in which an electric field having two-fold symmetry and a magnetic field having two-fold symmetry are superimposed.