MKS Instruments UK Ltd
Cirrus2 Hardware Manual – SP101017.100 June 2011
46
Ion Source cleaning
Cleaning while fitted to the analyser
Sometimes it is possible to clean the ion source without removing it from the analyser. For the user who has the
necessary equipment available including a means to suitably dry the analyser, it is usually worth trying this method
before removing or replacing the ion source. However, it is likely only to be successful where the source is contaminated
with loose or alcohol soluble deposits.
Remove the analyser from the vacuum chamber and place it on the bench in an upright position (the use of a small
bench vice is recommended), remove the filaments by following the appropriate guide for your type of analyser starting
on Page 43.
Insert the analyser into the measuring cylinder so that the knife edge side of the flange rests on the lip of the cylinder.
Note the level which the ion source comes to on the measuring cylinder before removing the analyser and filling the
measuring cylinder with sufficient iso-propyl-alcohol to cover the ion source only.
Note: the measuring cylinder should be of a diameter and length to accommodate the analyser.
Put the measuring cylinder into the ultra-sonic bath for 10 to 15 minutes.
Remove the analyser and allow any excess alcohol to drain off. Keep the analyser inverted (feedthrough upper most)
until it is dry.
Do not let any alcohol run down the analyser into the flange assembly as this will seriously damage the multiplier.
Check the condition of the ion source. A second or third wash may be required.
The ultra sonic bath may loosen some of the screws in the ion source. Take care not to throw these away when
discarding the alcohol
The analyser must be dried of cleaning solution before it can be used. We recommend the use of a clean oven for this
purpose. The oven should be set at 80
0
C and the analyser baked for at least two hours.
Check the documentation on your cleaning solution for guidelines on handling the substance and any fire or explosion
risks involved
After the bake period, check all the screws in the ion source are tight and re-fit the analyser to the vacuum chamber.
A further bake under vacuum will be required to drive off any remaining residue.