Image Focus And Objective Lens Astigmatism Correction; Photographing - Hitachi HF2000 TEM Operation Manual

8. Astigmatism correction of objective lens
•
Reset the OBJ STIGM-X and Y control knobs (stigmator)
on the left sub panel.
＊ This returns setting to the stigmator to preset level.
•
Set a magnification 2 or 3 times higher than used for

photographing.

•
Turn the focus control knob clockwise so as to obtain
slightly over-focused image, and a fringe appears outside
the collodion hole.
•
Adjust the OBJ STIGM-X and Y control knobs so that the width of the fringe outside the collodion
hole becomes uniform.
•
Manipulate the focus control knob so as to approach just focus from over-focus in order to narrow the
fringe width.
•
Find a as granularity a amorphous as possible and adjust the OBJ STIGM-X and Y control knobs so
that granularity a amorphous becomes finer granularity as shown in the figure below.

9. Image focus and Objective lens astigmatism correction

(Including Selected area electron diffraction (SAED))
This is to tell you how to correct objective lens astigmatism using amorphous film which is useful in
recording a high resolution image.
•
Center a small hole / particle / the sharp edge of sample.
•
Insert and center a suitable Selected Area (SA) aperture.
•
Press [DIFF] (left panel) and set the camera length to 0.80m using Magnification knob. If the central
spot (transmitted wave) is still disk, focus the pattern by adjusting Diffraction Spot (left panel).
Note: Open the beam to form a parallel illumination on the sample by turning Brightness
clockwise. Diffraction spots will become weaker and smaller. If the central spot is disk instead of
a spot, adjusting Diffraction Spot is needed.
7
左サブパネル
左サブパネル
Left sub panel