Chapter 2: Mass Cytometry and CyTOF XT
CyTOF XT System Components Overview
34
CyTOF XT User Guide
Vacuum Interface
The plasma, which is generated at atmospheric pressure (760 Torr), passes through the
vacuum interface.
The purpose of the vacuum interface is to efficiently transport ions from the plasma at
atmospheric pressure to the chambers that house the ion optics at less than 10
–
3
Torr.
CyTOF XT uses a 3-cone interface to transport the ion beam into a low-pressure vacuum:
sampler, skimmer, and reducer. The 3 cones are made of nickel and the sampler and
skimmer cones have a platinum-coated tip. The plasma containing the cell-induced ion
clouds enters through the sampler cone orifice into the sampler-skimmer region and then
passes through the skimmer cone to the skimmer-reducer region, and finally, through the
reducer cone. The ions that emerge from the reducer cone are accelerated and deflected
by an electrostatic field of the deflector toward the time-of-flight region. The interface
housing is liquid-cooled to dissipate the significant heat generated by the plasma.
Figure 25. The vacuum interface includes 3 cones: the sampler cone (light gray), and the skimmer and
reducer cones (dark gray), which are combined in the skimmer-reducer assembly.
The ion beam propagating through the cones contains non-ionized material and photons in
addition to ions. If not filtered, the neutrals can attach to instrument components and result
in signal drift, while photons that reach the detector are registered erroneously as ions. To
eliminate these problems, the ions in the beam are deflected perpendicularly by the
electrostatic quadrupole deflector. This turns positively charged ions toward the
downstream ion optics, while neutrals and photons continue toward the turbo molecular
pump.
Summary of Contents for CyTOF XT
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