Cirrus SP101013.111 – 10 October 2012
MKS Instruments UK Ltd., Spectra Products
48
3. Hold one of the barrel connectors firmly with your pliers and slacken the outermost screws (Items
1 and 6) until the barrel connector can be removed from the filament plate and the connecting lead.
4. Repeat the above for the other two barrel connectors.
5.
Remove the two M2 x 4 pan head screws that hold the filament plate in place and remove the
filament plate assembly. Carry out this step carefully so as not to damage the Source Cage.
6. Remove the Filament Screen (Item 5).
It is worthwhile at this stage 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. The signs to look for are
powdery deposits, 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, see Section 7.5.
8.6.2 Fitting new filaments
The fitting of new filaments is simply the reversal of the procedure for removing them. Care should be
taken at all stages to ensure that no shorts are introduced and that the analyser is kept clean.
1. Place and align the new Filament Screen on the source plate mounting posts.
2. Using tweezers, carefully offer the filament plate onto the mounting posts. Be careful not to touch
the source cage with either filament. There is no orientation of the filament plate required, except that
the mounting holes line up with the mounting posts.
3. Re-fit the two M2 x 4 pan head screws through the filament plate and filament screen and tighten
securely. Do not over tighten.
4. Re-fit each barrel connector in the same orientation as removed, sliding each barrel connector over
the connecting lead and filament post and while holding the barrel connector firmly with pliers, tighten
all screws.
5. Before re-fitting the analyser to your vacuum chamber, carry out Section 7.2 to check for any short
circuits.
