HPQ2-IP SP101009.102 – 10 October 2012
MKS Instruments, Spectra Products
31
It is worthwhile at this stage checking to see if the source requires any attention
especially if the filament(s) have broken because of an over pressure situation in
your vacuum system. With the filaments removed you have a clear view of the
source cage where the signs to look for are powdery deposits of tungsten oxides.
These will vary in colour but may be brown, blue, canary yellow or white depending
upon the precise circumstances which led to their formation. If these oxides are
present it is recommended that you refer to the section on source removal and
cleaning before proceeding any further.
7.9 Fitting New Filaments
The fitting of new filaments is simply the reversal of the procedure for removing
them. Care should be exercised at all stages to ensure that no shorts are introduced
and that the analyser is kept clean.
1. Place the filament assembly in the correct orientation onto the top of the source
ensuring that the filament wire does not touch any part of the source and thus
potentially cause damage. Be careful to fit the filament plate into the top of the
cylindrical foil repeller without bending the foil.
2. Refit the two M1.6 x 3 pan head screws that fasten the filaments to the ion
source.
3. Place a barrel connector over one of the filament connection wires and gently pull
the wire towards the ion source and fit the barrel connector to the appropriate
feedthrough. Tighten the two screws on the barrel connector. Be sure the wire up
to the barrel connector stays close to the analyser body.
4. Repeat step 3 for the other filament connection.
5. Check with your Ohmmeter for shorts.
6. Replace the analyser into your vacuum housing and again check for shorts or
grounding to the outer vacuum housing.