e-Vision and e- LP101013.100 – 01 January 2004
MKS Instruments, Spectra Products
29
7.5 Ion Source cleaning
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.
Below is a list of the tools and equipment you will require. We recommend that you
assemble the following items before you start. Remember that the instrument is
supplied with a tool kit that contained some of the things you will need.
Small jewelers screwdriver (2mm)
Pair of tweezers
Small pair of smooth jawed needle nosed pliers
Pair of clean cotton gloves
Clean bench on which to work
Ohmmeter
Clean container in which to put small parts
Ultra-sonic bath
Measuring cylinder
Iso-propyl-alcohol
Some method of holding the analyser securely in an upright position (a small bench
vice is ideal).
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 as described in Section 7.4.1 .
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.
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
.
Note: 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.