Thermo Scientific TSQ Series Hardware Manual page 44

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Functional Description
Mass Spectrometer
The lens L0 is a metal cylinder with a small hole in one end through which the ion beam can pass.
A potential of between 0 and ±3 V (negative for positive ions and positive for negative ions) is
applied to lens L0 to aid in ion transmission. Lens L0 also acts as a vacuum baffle between the Q00
and Q0 ion optics chambers.
Q0 Ion Optics
The Q0 ion optics transmits ions from the Q00 ion optics to the mass analyzer. The Q0 ion optics
includes the Q0 quadrupole and lenses L11 and L12.
The Q0 quadrupole is a square array of square-profile rods that act as an ion transmission device.
See
along the axis of the quadrupole. The Q0 offset voltage increases the translational kinetic energy of
ions emerging from Q00.
Figure 21. Q0 quadrupole
The Q0 offset voltage can also be used to fragment ions. In ion source collision-induced
dissociation, the offset voltage (typically -30 V to +30 V) imparts enough kinetic energy to the ions
so that, when they collide with solvent or air molecules, the ions dissociate to form product ions.
The translational kinetic energy imparted to the ions determines the degree of dissociation. At low
energies, adduct ions convert to sample ions by collision-induced dissociation without fragmenting.
At higher energies, molecular ions can fragment and thereby enable primitive MS/MS/MS analysis.
The L11 and L12 lenses are metal disks with a circular hole in the center through which the ion
beam can pass. See
applied to the lens accelerates (or decelerates) ions as they approach the lens to focus the ion beam
as it passes through the lens. The value ranges between 0 and ±300 V. Lenses L11 and L12 also act
as a vacuum baffle between the Q0 ion optics chamber and the mass analyzer chamber.
26 TSQ Series Hardware Manual
Figure 21. An RF voltage applied to the rods gives rise to an electric field that guides the ions
Figure 22. Together they act as a two-element cone lens. An electrical potential
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