Stanford Research Systems RGA100, Руководство по эксплуатации и программированию

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Quadrupole filter cleaning 8-23
SRS Residual Gas Analyzer
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.
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.
Note : We do not recommend cleaning the alumina spacers, but if signs of severe
contamination are evident, ultrasound clean the two rings for 15 minutes with diluted
cleaning solution, and bake them out for 2 hours at 180
q
C after a thorough rinsing.
9. 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 grit down to 12000 until the metal surface has a fine
polished appearance.
Warning: Do not remove excessive material from the surface
of the precision-ground rods.
After all metal surfaces have been polished, they must be cleaned to remove all the
abrasive compound from their surface. Begin by placing the rods in a beaker with the
ultrasonic cleaner solution (Note: Any good quality cleaning compound that leaves
no residue after rinsing is good for this job.) Place the beaker in the ultrasound
cleaner and agitate for 30 minutes. Decant off the cleaning solution, and repeat the
above agitation with 4 to 5 consecutive washes with distilled water to remove the
cleaning solvent. Following the rinses, blow dry the rods with filtered dry nitrogen
and then bake them out in an oven at 180
q
C for fifteen minutes. Warning: After the
parts have been cleaned and baked out, they should only be handled wearing powder-
free latex gloves.
10. Head Reassembly: Only a rough outline of the complete reassembly of the probe is
presented here. Use the RGA Assembly Drawing of Chapter 9 and your own notes
as a visual aid during this process.
Begin by assembling the quadrupole mass filter. Loosely attach the cleaned rods to
the alumina spacers with the spring-loaded, perforated screws. Tighten the screws
following the
systematic procedure described next. Work on one spacer at a time,
using a single, small turn of the screwdriver on each screw. After a single round of
eight screws, hold a spacer in each hand, and slightly torque the assembly back and
forth about its axis to make sure the rods are comfortably seated on their alignment
grooves. Repeat this tightening procedure, one spacer at a time, constantly checking
the alignment, until the spring washers are completely compressed. Once the
quadrupole assembly is completed, mount the focus plate and the anode grid on it.
Use new e-clips to hold the two ionizer plates against the top alumina spacer, but do
not install any e-clips on the bottom grooves of the connection rods at this time.
Next, mount the quadrupole assembly on the exit plate of the feedthru flange and
secure it in place tightening the two connector screws and inserting an e-clip in the
exit plate align rod groove. Insert the rest of the rods in their correct locations and,
while checking for the correct alignment of their grooves and slots, tighten the rest of
the feedthru connector screws. Once the rods are in place, attach the two RF ribbon
connectors to complete the quadrupole filter assembly.