| 摘要 |
The invention relates to a method for adjusting or aligning one or more optical elements in a Transmission Electron Microscope (TEM), the TEM (500) equipped with an objective lens (512) for guiding a beam of electrons to a sample (508) and the TEM showing a diffraction plane (514) in which at least a beam of unscattered electrons is focused, the TEM equipped with a structure (518,410) to enhance the Contrast Transfer Function (CTF), said structure situated in the diffraction plane or an image thereof, the method comprising adjusting or aligning the optical elements, characterized in that irradiation with unscattered electrons of the structure during said adjusting or aligning is prevented (602) by deflecting the beam of unscattered electrons away from the structure.
The structure to enhance the CTF can, for example, be a phase plate, a single side band device, or a 'tulip' (410).
In a preferred embodiment of the method the optical element to be aligned is the phase enhancing structure itself. |
