Teledyne Princeton Instruments PI-MTE, System Manual

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78 PI-MTE System Manual Issue 6
7.5 Cooling Troubleshooting
This section provides troubleshooting information for Cooling-related issues.
7.5.1 Camera does not achieve temperature lock
If the indicator does not turn green after 30 minutes:
• The temperature setting may be at a temperature colder than the specified limit
or the environment could be particularly warm. If this occurs, try a higher
temperature setting.
Make sure you are selecting a temperature that is
acceptable for your particular camera and CCD array.
• The coolant may not be flowing fast enough. Check the coolant flow rate.
7.5.2 Vacuum Deterioration
With time, there may be a gradual deterioration of the camera’s vacuum. This may
affect temperature performance and it may no longer be possible to achieve
temperature lock at the lowest temperatures. In the kind of low-light imaging
applications for which cooled CCD cameras are so well suited, it is highly desirable to
maintain the system’s temperature performance because lower temperatures provide
less thermal noise and better signal-to-noise ratio.
7.5.2.1 In-Vacuum Applications
Vacuum deterioration is normal for PI-MTE cameras that are designed for operation in
vacuum chambers but are temporarily being operated with a visible nose in air. The
elastomer gasket between the nose and the middle enclosure is not intended to provide
a permanent vacuum. If you have the appropriate equipment and personnel with the
necessary expertise available, you may pump down the camera at your facility. Refer to
Section D.2, Replace the Open Nose with the Visible Nose , step 12 through step 18 on
page 110.
7.5.2.2 Out-of-Vacuum Applications
The camera will have an Indium seal between the nose and the middle enclosure. If you
have the appropriate equipment and personnel with the necessary expertise available,
you may pump down the camera at your facility. Refer to
Section D.2, Replace the Open
Nose with the Visible Nose , step 12 through step 18 on page 110.
CAUTION!
!
The CCD array is subject to damage from condensation if
exposed to the atmosphere when cold. For this reason, the
camera should be kept properly evacuated or backfilled
with dry nitrogen, free of oil or other contaminants.