Npd Maintenance; Thermionic Source - Thermo Scientific TRACE GC Ultra Maintenance And Troubleshooting Manual

Chapter 13
Maintaining a Nitrogen Phosphorus Detector

NPD Maintenance

To ensure optimum performance of the NPD, you must keep it clean and free of
dust and deposits. Symptoms such as reduced sensitivity and increased noise
indicate that detector cleaning or thermionic source replacement could be
necessary.
To properly maintain the Nitrogen-Phosphorus Detector, you should perform the
following sequences:
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Thermionic source

The thermionic source installed in the detector may be removed and replaced with
a new one or with a source having different coating.
NOTE New thermionic sources may require slightly different values of source heating current to
produce the same signal observed with a previous thermionic source.
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cleaning the jet.
replacing the jet.
cleaning the collecting electrode.
replacing the collecting electrode.
replacing the thermionic source.
Maintenance and Troubleshooting Manual

NPD Maintenance