8CI Maintenance
To Clean the CI Source
242 5977B Series MSD Operating Manual
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Procedure
1 If the contamination is serious, such as an oil backflow into the analyzer,
seriously consider replacing the contaminated parts.
2 Abrasively clean the surfaces that contact the sample or ion beam.
Use an abrasive slurry of alumina powder and reagent-grade methanol on a
cotton swab. Use enough force to remove all discolorations. Polishing the
parts is not necessary; small scratches will not harm performance. Also
abrasively clean the discolorations where electrons from the filaments
enter the source body.
3 Rinse away all abrasive residue with reagent-grade methanol.
Ensure all abrasive residue is rinsed before ultrasonic cleaning. If the
methanol becomes cloudy or contains visible particles, rinse again three
times.
4 Separate the parts that were abrasively cleaned from the parts that were not
abrasively cleaned.
If the CI repeller insulator is dirty, clean it with a cotton swab dampened with
reagent-grade methanol. If that does not clean the insulator, replace it. Do not
abrasively or ultrasonically clean the insulator.
Figure 79. CI source parts to be cleaned
Entrance lens Ion focus lens Drawout cylinder Drawout plate Source body Repeller