Hardware manual

Maintenance 4
Agilent 7500 Series ICP-MS Hardware Manual 4-75
Maintaining the Lenses (Agilent 7500a)
There are two sets of lenses in the Agilent 7500a. These are the extraction
lenses and the main lens assembly, which is comprised of the Einzel lens and
the Omega lens. In this procedure both sets of lenses are removed and
dismantled before cleaning each lens element individually. However, each lens
assembly can be cleaned separately. It is critical to reassemble the ion lenses
in exactly the same order as before dismantling. Work on a large clean surface
where each piece can be kept in the order that it has been removed.
To clean the main lens assemblies, it is necessary to open the analyzer vacuum
chamber. The section, “Working Inside the Vacuum Chamber”, contains
procedures to correctly open and close this chamber.
In addition to the recommended cleaning frequency in the maintenance
schedule, the lenses should be cleaned if any of the following symptoms are
observed:
• The ion signal is unstable. For example, a signal drift of more than 10% in
an hour. In this block, the cause may be other parts such as the sample
introduction.
• After changing the lenses' voltage in the MassHunter Workstation (or
ChemStation) software, the resulting ion signal changes very slowly. For
example, vary the parameter drastically step by step and it takes more than
1 second for the signal to be stabilized.
• While tuning, when changing the tuning parameter value, the response
speed of the signal is different between changing the value from the plus
direction than changing it from the minus direction.
NOTE
If you are using the Agilent 7500cs/cx, refer to “Maintaining the Lenses (Agilent 7500cs or
7500cx)” on page 4-91.