The cations formed in the ionisation chamber leave this chamber due to the positive charge on the repeller electrode. Before entering the mass analyser, the ions are focused (into a beam) and accelerated by magnetic and electric fields that are perpendicular to one another.
The electric field can be used to accelerate the ions (change their velocity).
The magnetic field can be used to change their direction.
Ions passing through slit 1 do so because the force due to the magnetic field that they are experiencing is exactly balanced by the force due to the electrical field.
The magnetic field can be used to change their direction.
Ions passing through slit 1 do so because the force due to the magnetic field that they are experiencing is exactly balanced by the force due to the electrical field.
Because the charge on most ions in a mass spectrometer is the same (+1), the path depends on their mass.
Ions of lighter mass are deflected by the magnetic field into a circular arc with a smaller radius. This means that they are deflected from the linear path to a greater extent.
A mass spectrum shows the ions of different mass detected over a range of magnetic field strengths.
Ions of lighter mass are deflected by the magnetic field into a circular arc with a smaller radius. This means that they are deflected from the linear path to a greater extent.
The diagram shows a spectrometer where the magnetic field is adjusted so that an ion of a specified mass/charge ratio reaches the detector.
Lighter or heavier ions are not detected at this magnetic field strength.
Ions of different mass can be detected at different magnetic field strengths.
Lighter or heavier ions are not detected at this magnetic field strength.
Ions of different mass can be detected at different magnetic field strengths.
A mass spectrum shows the ions of different mass detected over a range of magnetic field strengths.