MKS Instruments UK Ltd
Cirrus2 Hardware Manual – SP101017.100 June 2011
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5. Maintenance
Overview
Periodic maintenance of your Cirrus2 will be required to ensure optimal performance. The following sections provide
detailed information on filament replacement, ion-source cleaning or replacement and capillary maintenance.
If you feel uneasy about tackling any of the following maintenance topics, please contact us for advice or to arrange an
on-site service visit where we will carry out the work.
Quadrupole Ion Source
The ion source contains two filaments, only one of which will be in use at any one time. The filament is heated to
approximately 2000 degK at which temperature it emits electrons, which are used to produce the ions required by the
quadrupole filter. At this high temperature, there are two deleterious effects;
The filament material slowly evaporates and condenses upon the surrounding surfaces. This effect is extremely slow but
would require, from time to time, the cleaning of the surrounding source plates and ceramics and the replacement of the
filaments.
The second effect is similar to the first except that the vacuum, under which the source is operating, has either a high
oxygen or water content. Then instead of metal being deposited upon the surrounding source plates, layers of metal
oxides are deposited. Being insulators, these have a far more noticeable effect upon the performance of the source and
therefore a more frequent cleaning program should be adopted.
Capillary Inlet
The Cirrus system uses a capillary inlet to admit sample gas into the chamber for analysis. MKS Spectra produce a
variety of capillary inlets but the Flexil capillary is dealt with in this manual.
The Flexil capillary inlet assembly consists of a white PTFE tube containing a fine bore stainless steel tube, down the
centre of which is threaded a 0.32mm I.D. fused silica tube.
A low voltage power supply is connected across the stainless steel tube to provide heating of the fused silica tube.
You may need to replace the fused silica capillary tube which forms part of the capillary inlet assembly, if it has been
damaged or becomes blocked.
Frequent baking can cause the flexsil liner to become brittle and break at even less than acute angles and over time, a
build-up of particulates can leak to a blockage.
Orifice Disk
A pressure reducing orifice disk is fitted to the inlet flange of the RGA chamber, a build-up of particulates can block the
holes in this disk.
Pumping System
The turbo pump utilizes a “wet bearing” and must be serviced yearly to avoid premature failure. The internal diaphragm
pump must also be included in your service plan.
Details of servicing are provided in the relevant pump user manuals supplied with your Cirrus2.
