Gatan UltraScan 894, Руководство пользователя

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Most Often Asked Questions
UltraScan Use r ’s Guide Reference Series Rev 1.0 5-6
If you have a clean vacuum in the camera chamber area, between once or
twice a month is enough. But if you have backstreaming from your
diffusion pump, you will need to do it more frequently. The camera should
only be warmed for several hours or overnight, but not longer. A quick
way to see if oil is accumulating is to take a uniform illuminated image at
40 or 60 kV.
12. The camera takes a long time to insert/retract, what should I
do?
Check your compressed-air pressure. It should be between 30-60
2
cm N
.
Then the pressure regulator on the red (retract) line should be adjusted so
that insert and retract times are equal.
13. Why can’t I expose photographic film with the camera on
and inserted?
When the camera is on and inserted, the TEM shutter is controlled by the
CCD camera software. In order to protect the CCD, the software (default
setting “shutter normally closed”) closes the TEM shutter if the CCD is not
set to acquire any images. In this case, one cannot expose the photographic
film.
To expose the film, one should (1) simply retract the CCD camera, or (2)
force the shutter open with the switch on the front panel, or (3) set the
shutter configuration to “shutter normally open”.
14. I see a ghost image that won’t go away, what should I do?
It is possible that the dark or gain reference has a ghost image. Try clearing
and re-acquiring the reference images. You can remove the dark reference
image by choosing
Remove dark references under the Camera menu.
If the ghost image still exists, it is likely caused by exposing intense beam
on the CCD. Spread out the beam and set the illumination so you have
about 10,000 counts/sec ( in 2 times binned mode) and switch the shutter
switch on the controlle r to Open. Expose the scintillator for 2-3 min,
switch back to Auto, and take another image.