6
Prefilter and Quadrupole
Thermo Scientific
DSQ II Hardware Manual
185
Second, helium atoms (not ions) coming from the ion source cause noise if they reach the exit
lens or ion detector. This is known as neutral noise. Helium atoms cannot negotiate the bend
in the prefilter. Therefore, the noise is virtually eliminated. This leads to better signal-to-noise
ratio and lower limits of detection. In addition, higher GC helium flows can be used without
causing excessive amounts of noise that would blind an instrument without a curved prefilter
to low-level signals.
Figure 100.
Prefilter
Figure 101.
Quadrupole Mass Filter
Содержание DSQ II
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Страница 36: ...1 Basic Operations Shutting Down the GC MS System 20 DSQ II Hardware Manual Thermo Scientific ...
Страница 182: ...4 Vacuum System and Gas Inlets Gas Inlet Components 166 DSQ II Hardware Manual Thermo Scientific ...
Страница 198: ...5 Ion Source and Inlet Valve Inlet Valve Upgrade 182 DSQ II Hardware Manual Thermo Scientific ...
Страница 202: ...6 Prefilter and Quadrupole 186 DSQ II Hardware Manual Thermo Scientific ...
Страница 206: ...7 Ion Detector Electron Multiplier 190 DSQ II Hardware Manual Thermo Scientific ...
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