Gatan ORIUS SC 200D - Critical Warnings; Conditions to Avoid for Camera Protection

ORIUS ™ 833 CCD Camera User’s Guide Series Rev 3 vii
0. WARNING
As with any CCD camera or the viewing screen in the TEM it is possible to permanently burn the
scintillator material with the electron beam. The new SC200D has been designed specifically to
handle the intense beam conditions in Diffraction mode. However, precaution should still be made so
as not to cause damage in extreme conditions that require very long exposure times or time periods
needed for in-situ recording.
To avoid an expensive service visit, recoating of the scintillator and down time please read the
following guidelines and avoid the stated conditions that could produce damage. User damage due to
mis-use or by not following these warnings is not covered by the Warranty.
Conditions to avoid:
• Diffraction patterns with bright central spots
Before going into diffraction mode dramatically reduce the intensity of the electron beam. If
you start to see streaking or require exposures of less than 50ms you have too much beam.
On a thin film (for example carbon) 99.9% or more of the beam will be in the center spot. This
could be as much as 100nA on a typical TEM. Reduce this by going to a smaller spot size,
smaller condenser aperture, use of a selected area aperture and reducing the emission current of
the gun.
A diffraction pattern taken for 1 second with a lower intensity will look better on the camera
(and will not damage the scintillator) than one taken for 1ms at a higher intensity.
If you find yourself using camera exposures of 1 to 50ms in diffraction mode with high beam
intensity (large spot sizes) you are going to possibly burn the scintillator.
If the diffraction pattern is very easy to see on the TEM viewing screen using your eyes, it is
probably going to be too bright to be viewed or captured with the digital camera properly.
• Leaving the beam at cross-over at low magnification. If you have an image on the camera
and you need to leave the beam focused on one point, lower the TEM screen or retract the
camera to avoid exposure to the electron beam, hence protecting your scintillator.