Hardware manual

6-16 Agilent 7500 Series ICP-MS Hardware Manual
6 Technical Information
Figure 132 Schematic Diagram of Omega Lens
The ions then pass through the QP focus and the Plate bias. The purpose of
these lenses is to decelerate ion speed and to focus the ions. The QP focus and
the Plate bias are operated at zero or slightly positive voltage.
When the ion lens voltage is changed drastically and the signal, in the
sensitivity tuning mode, does not change rapidly or when the signal is
unstable and reproducibility is poor, the ion lens may be dirty and cleaning is
required. Frequency of cleaning depends on the samples analyzed. For
example, if the instrument is used for tap water analysis 8 hours/day and 7
days/week, cleaning of the Extraction lens will be required every 2 months
and that of the Einzel and Omega lenses will be every 4 to 6 months. If samples
are cleaner than tap water (e.g. semiconductor), the frequency of lens cleaning
will decrease. When the ion lenses become dirty, ions burn into the surface of
the lens, often observed as a brown color on the extraction lenses.
+
+
-
-
: Photon
: Ion
M
+
Omega Bias QP Focus
Omega (+)
Omega (-)
Plate Bias
Pre-Filter
Q-Pole