Ion Optics; Q0 Ion Optics - Thermo Scientific TSQ Series Hardware Manual

The vent prevent ball falls into the space occupied by the ion transfer tube when the tube is
removed, thus preventing air from entering the vacuum manifold. The vent prevent ball allows you
to remove the ion transfer tube for cleaning without venting the system.
The ion sweep cone is a metallic cone over the ion transfer tube. The ion sweep cone channels the
sweep gas towards the entrance of the tube.
The ion source interface is enclosed in a vacuum chamber that is evacuated by the forepump to a
pressure of approximately 1.5 Torr.
Figure 15. Ion transfer tube
Front

Ion Optics

The ion optics focus the ions produced in the API source and transmit them to the mass analyzer.
The TSQ mass spectrometer uses two ion optics elements:
• Q00 ion optics

• Q0 ion optics

Q00 Ion Optics
The Q00 ion optics are the ion optics that are located closest to the API source. Q00 ion optics
include either the tube lens and skimmer or the S-lens and exit lens, the Q00 RF lens, the ion
source interface cage, and the lens L0. See
On the TSQ Quantum Access and TSQ Quantum Ultra, ions from the ion transfer tube enter the
tube lens. See
ions toward the opening of the skimmer. An additional potential of between 0 and ±250 V
(positive for positive ions and negative for negative ions), called the tube lens offset voltage, can be
applied to the tube lens. This accelerates the ions into background gas that is present in the ion
transfer tube-skimmer region. Collisions with the background gas aid in the desolvation of the ions
and increase sensitivity. If the tube lens offset voltage is too high, however, collisions with the
background gas can be energetic enough to cause ion fragmentation. This fragmentation, called
ion source collision-induced dissociation (CID), decreases sensitivity. When you tune the TSQ
mass spectrometer, you adjust the tube lens offset voltage to maximize sensitivity by balancing
desolvation with fragmentation.
Thermo Scientific
Figure 16. The tube lens has a mass-dependent potential applied to it to focus the
Figure 14.
2
Functional Description
Mass Spectrometer
TSQ Series Hardware Manual 23