SRS Labs QMS 100 Series, User Manual

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Cleaning 5-17
Technical Reference
Figure 1 Probe Removal for Quadrupole Filter Cleaning
6. Carry the probe to a clean, dust free area immediately. Avoid contamination using handling
procedures compatible with high vacuum requirements.
7. Hold the probe in a secure upright position and do a thorough visual inspection of the unit.
Check for loose, damaged, misaligned and severely contaminated components. If excessive
contamination is evident take the necessary steps to identify and eliminate the contamination
sources in the vacuum system. Carefully inspect the ionizer and, if any problems are detected,
replace the filament and/or the ionizer as part of this maintenance procedure. Inspect the
CDEM for signs of arcing and contamination. If necessary replace the CDEM as part of this
maintenance procedure.
8. Head disassembly: Only a rough outline of the complete disassembly of the probe is
presented here. Use the RGA Assembly Drawing of Chapter 9 as a visual aid during the
process.
9. Note the placement of all parts and their orientation before disassembly!
10. Begin by removing the filament following the necessary steps from the “Filament Replacement”
procedure described in this chapter. Be very careful not to damage the thoria coating if you
intend to use the same filament during reassembly.
Next, remove the CDEM following steps from the “CDEM Replacement” procedure. Store the
multiplier in a dry box or desiccator. Loosen the seven screws that fasten the 1/8” diameter
rods to the feedthru connectors, and remove the bowed e-clip from the exit plate align rod that
is located right above the CDEM. You can now separate the entire quadrupole assembly from
the detector/feedthru assembly. There are no serviceable parts in the flange. Set it apart in a
safe, clean area. Next, separate the ionizer from the quadrupole filter by removing the e-clips
that hold the 1/8” diameter rods in place. Store the ionizer electrodes in a safe clean area.
Disassemble the quadrupole and set apart the precision ground rods for cleaning.
11. Note : This is a good time to carefully inspect all the components of the probe for damage and
contamination. Replace or clean any parts that are suspect.
12. Warning : We do not suggest cleaning the alumina spacers but, if signs of severe contamination
are evident, a quick ultrasound cleaning with acetone, followed by a 2 hour bakeout at 100-
150
°
C is recommended.
13. Rods cleaning: Use the Micro-Mesh abrasives to clean the rods. Begin by using the finest
abrasive which will remove the residue, normally 3200 grit. Then consecutively use the next finer