Agilent Technologies 7500 ICP-MS Operator's Manual page 121

Agilent 7500 ICP-MS ChemStation Operator's Manual
Tuning
• Extract 2
It focuses the ion beam from the extraction lens. An element of low mass gets
maximum sensitivity at low voltage. On the other hand, an element of high mass
gets maximum sensitivity at high voltage. Therefore, set a value to get optimum
sensitivity foe the whole mass range.
• Omega Lens-ce
Separating the ions from photon and introduce the ions to the Reaction Cell.
Adjusts to get good sensitivity for all masses.
• Omega Bias-ce
Provides the same potential at the entrance and exit of the Omega lens block. It
must be used at voltages more positive than -40V. The more negative voltage, the
higher the sensitivity, but the background might increase.Cell Focus
Locates on the first lens of the Reaction Cell. The voltage is set to 0V at all times.
This lens is not displayed as a tuning parameter.
• Cell Entrance
Adjust to get enough sensitivity for all masses. It is necessary to set a lower
voltage than the OctP bias. If the voltage is set higher than the OctP bias,
polyatomic ions may increase on some specific masses.
• QP Focus
Decelerates and focuses the ions and introduces the ions to the Q-pole. Adjust to
get good sensitivity for all masses.
• Cell Exit
Adjust to get enough sensitivity for all masses in standard mode. There is an
optimum value near the OctP bias. If the OctP bias voltage is changed, the cell
exit value also needs to be simultaneously changed by the same degree.
• Plate Bias
It re-focuses the ion beam. This lens is set to the same voltage of Cell Exit
automatically.
• OctP RF
Adjust to get enough sensitivity for all masses. A typical range is from 150 V to
200 V. An element of low mass gets maximum sensitivity at low voltage. On the
other hand, an element of high mass gets maximum sensitivity at high voltage.
• OctP Bias
Adjust to get enough sensitivity for all masses. The optimum value in standard
mode is different from that in reaction mode and cool mode.
• QP Bias
It controls the speed of ions when an element ion passes through the Q-Pole and
prevents polyatomic ions of low energy from passing. When peak shape and
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