Reinstalling The Top Cover Of The Mass Spectrometer; Electron Multiplier Replacement - Thermo Scientific LTQ Series Hardware Manual

Reinstalling the Top Cover of the Mass Spectrometer

Electron Multiplier Replacement

Thermo Scientific
 To reinstall the top cover of the mass spectrometer
1. Using the 1/4 in. hex driver on the door latch, open the front door of the mass
spectrometer (Figure 68
2. Place the top cover on the mass spectrometer and slide it forward until it is flush with the
front panel.
3. Using the Phillips screwdriver, tighten the two captive screws to secure the top cover.
4. Close the front door of mass spectrometer and use the 1/4 in. hex driver to tighten the
latch.
5. Reconnect any tubing between the syringe pump, LC pump, or LC and the API source to
accommodate your instrument configuration.
Electron multipliers have finite lifetimes, and their surfaces degrade over time, causing more
voltage to be required to achieve the specified gain. Factors contributing to a decrease in the
lifetime are: air exposure (causes oxidation), electron flow (produces internal heat), heat, poor
vacuum conditions, and water (causes arcing).
You might need to replace one or both of the electron multipliers, as applicable, if either of
these symptoms persists:
• Excessive noise in the mass spectrum produced by the electron multiplier
• Inability of the multiplier gain calibration procedure to achieve a gain of 4 × 10
per ion with the maximum voltage supplied by the multiplier power supply
You can read the current value of the electron multiplier voltage in the Ion Detection System
dialog box. In the Tune Plus window, choose Setup > Ion Detection System.
Note The LXQ mass spectrometer has only one electron multiplier. Adjust the following
procedure accordingly.
For Field Service use only
Electron multiplier, anode, and base shield
Electron multiplier shield retainer (Velos Pro only)
on page 100).
5
Maintenance
Electron Multiplier Replacement
5
electrons
Part number
See page 135.
97655-20003
LTQ Series Hardware Manual 115