Enhanced imaging mode for transmission electron microscopy

摘要

In the magnetic optical system of a transmission electron microscope (TEM), the increased strength of a second objective lens is used to increase the longitudinal energy dispersion by forming an image at a magnified second back-focal plane. The electric current distribution of other lenses in the microscope is reconfigured to compensate for any offsets introduced by the modified second objective lens. A plurality of deflectors are installed which enable the manipulation of the electron beam electronically between the specimen and the second back-focal plane. The magnified second back-focal plane is projected onto the selected-area aperture, allowing the use of the existing selected-area aperture as an objective aperture to achieve an energy filtering effect which improves the image contrast and resolution.