Thermo Finnigan LTQ - Cleaning the Ion Detection System; Reinstalling the Top Cover Plate of the Vacuum Manifold

MS Detector Maintenance
Cleaning the Q0 and Q1 Ion Guides
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4-36 ______________________ Finnigan LTQ Hardware Manual _______________________
Cleaning the Ion Detection System
The conversion dynode and electron multiplier of the ion detection system
must be kept dust free. Clean the conversion dynodes and electron multipliers
whenever you remove the top cover plate of the vacuum manifold. Cleaning
the conversion dynodes and electron multipliers involves only blowing them
with clean, dry gas such as nitrogen. Freon gas is not recommended. Do not
use liquids to clean the ion detection system components. Always cover the
opening in the top of the vacuum manifold with a large, lint-free tissue
whenever you remove the top cover plate of the vacuum manifold.
Go on to the next topic: Reinstalling the Top Cover Plate of the Vacuum
Manifold.
Reinstalling the Top Cover Plate of the
Vacuum Manifold
Use the following procedure to reinstall the top cover plate of the vacuum
manifold:
1. Remove the tissue from the opening in the top of the vacuum manifold.
2. Check the O-ring that surrounds the opening for signs of wear, and
replace it if necessary (P/N 97055-40005). Make sure that the O-ring is
seated properly.
3. Carefully lift the top cover plate up by its two handles and turn it over.
Orient the top cover plate such that the electron multiplier is over the
conversion dynode. Carefully insert the guide posts on the underside of
the top cover plate into the guide holes in the vacuum manifold. Slowly
lower the cover plate onto the opening in the vacuum manifold. Take care
not to damage the components on the underside of the cover plate. Ensure
that the cover plate is seated properly on the vacuum manifold.
4. Reconnect the three cables to the Top Cover PCB. See figure 4-14 on
page 4-31.
5. Reconnect the electron multiplier high voltage coaxial cables that come
from the electron multiplier power supply.
6. Reconnect the electrometer cable to the Electrometer PCB.
Go on to the next topic: Reinstalling the Top Cover of the MS Detector.
Note. Periodically, remove any contamination that might be on the inner
walls of the manifold by wiping the inner walls with a lint-free tissue soaked
in HPLC-grade methanol. Use a cotton-tipped applicator soaked in methanol
to clean around inlets and feedthroughs.