Vacuum System - Thermo Scientific LTQ Series Hardware Manual

Vacuum System

Thermo Scientific
The LXQ uses one and the LTQ XL and LTQ Velos use two continuous dynode electron
multipliers. The Velos Pro uses two discrete dynode electron multipliers that provide a higher
linear dynamic range. The one or two electron multipliers mount on the top cover plate of the
vacuum manifold next to the mass analyzer. The electron multiplier amplifies the signal and
includes a single or common anode that collects the electrons produced by the cathode. The
data system records the combined current that leaves the one or two electron multipliers, as
applicable, through a common anode.
Because of the off-axis orientation of the ion detection system relative to the mass analyzer,
neutral molecules from the mass analyzer tend not to strike the conversion dynode or electron
multiplier. As a result, the noise from neutral molecules is reduced.
The vacuum system evacuates the region around the
ion detection system. The vacuum system includes the following components
• Vacuum Manifold
• Turbomolecular Pump
• Forepumps
• Convectron Gauge
• Ion Gauge
2
Functional Description
API stack, ion optics, mass analyzer, and
LTQ Series Hardware Manual
Mass Spectrometer
(Figure 22):
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