Theory of Operation
The heart of the magnetic sector mass spectrometer is the spectrometer tube where separation of the gas components occurs.
As shown right, a sample is introduced to the mass spectrometer ion source where positive ions are generated by electron bombardment. A positive potential propels these ions into the field free spectrometer tube and toward the magnetic field region. The degree of deflection of the ion within the magnetic separator depends on the ion's velocity as well as its mass-to-charge ratio. By altering the potential at the ion source, the velocity of a given ion changes, thereby allowing different masses to be focused and detected at the opposite end of the spectrometer tube by the ion collector. Narrow, fixed focusing slits at both ends of the spectrometer tube serve to focus the ion beam and improve the resolution of the system. These ions arrive at the collector and generate a proportional electrical signal that is the basis for measurement.
