MKS HPQ3, Руководство по оборудованию

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MKS Instruments UK Ltd
HPQ3 Hardware Manual – SP101019.101 October 2012
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Routinely there is only one area of the analyser that requires any maintenance, this is the 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 deg K 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.
You should not attempt repair other than replacing the filaments or cleaning / replacing the ion-
source.
Further servicing may be carried out on-site, or on an RTB basis.
Please contact your local MKS representative for further information.
7.2 Ohmmeter analyser checks
There are a number of circumstances when carrying out some simple checks with an ohmmeter
can be worthwhile. If you suspect a failed filament, or want to check for shorts-circuits following
maintenance, performing some simple checks can save a great deal of time.
In carrying out these checks, we can legitimately accept two ranges of meter readings as possibly
acceptable and anything outside these ranges as being a definite fail. Any readings less than 1
ohm we can assume as a short-circuit and any reading above 5 Meg Ohm (5x10
6
ohms) as being
open circuit. The following assumes that the analyser is still on the vacuum system and details all
the possible tests.
Tools required: Ohmmeter with leads
Please refer to Page 40 for analyser pin numbers.
1. Attach a meter lead to pin 1 of the analyser feedthrough.
2. Connect the other lead to the analyser flange, you should read a short circuit. If not, you have
either a serious problem, or more likely a faulty meter/meter leads. If after checking your meter, an
open circuit still exists, contact your nearest MKS service centre for advice.