JEOL JSPM-5200 Instructions Manual page 91

５ MEASUREMENT OPERATION
■ Setting scanning parameters
Before carrying out an approach, set the scanning parameters required for observation.
Alt hough thes
obse rvation, you usually set the parameters as follows.
Scan Size
Click
highlighted, enter 1.000 (1 um) using the keyboard and press the Tab key to
finalize the input. Or, click on the
and select a numerical value near 1 000 nm.
The maximum scan ning range depends on the scanner installed. In actual practice,
the scanning area should be changed to the region you want to observe.
Clock/ms
C lick on the
This is the parameter that determines the scan speed. Naturally, this parameter
should be changed according to the observation area and the unevenness of the
specimen surface.
Filter/Hz
Click on the
p ull-down menu.
Filter/Hz is the parameter that determines the response speed of the feedback circuit.
The larger the set value is, the faster the response speed becomes, thus producing a
sharp image. But the feedback circuit easily oscillates. As a general rule to follow,
set the highest speed at which the feedback circuit does not oscillate while watching
the image during scanning.
Loop Gain
Click on the
pull-down menu.
The setting determines th
the higher the response gain becomes, thus obtaining a good image from an uneven
specimen surface, but the feedback circuit easily oscillates.
5-28
e parameters differ depending upon the specimen and the purpose of
on the Scan Size selection box. When the numerical value is
button in the Clock/ms selection box and select 100.00 us.
button in the Filter/Hz selection box and select 1.0 from the
button in the Loop Gain selection box and select 8 from the
e gain of the feedback circuit. The larger the set value is,
button in the Scan Size selection box
TMPM5200-2