Quadrupole mass filter with means to generate a noise spectrum exclusive of the resonant frequency of the desired ions to deflect stable ions
A mass spectrometer for the separation or separate indication of ions of different specific electric charges is reported. The instrument uses a periodically varying electric field in its analyzing section to excite the injected ions into oscillations while traveling along their trajectories which are either stable or unstable depending on specific parameters. Only stable trajectory ions pass through the electric field to the collector for indication.
Langmuir, R. V.↗