During the collision an electron is knocked out of the sample atom or molecule, leaving it with a positive charge. In other words, positively-charged gaseous ions are formed. McREL These newly-formed ions are then pushed out of the ionization chamber by an electric field applied between two metal grids. The negative grid, which is full of holes, allows the accelerated ions to pass through it and leave the ionization chamber. The speeds to which the ions can be accelerated by the electric field are determined by their masses.
Lighter ions reach higher speeds than do the heavier ones.
The ion beam passes through an externally-applied magnetic field. The magnetic field created by the beam of moving charged particles interacts with the external magnetic field. If the beam of a mixture of particles of different masses is allowed to hit a photographic plate, the particles converge at different points, corresponding to the different radii of their semicircular paths. There are many variations in the process of mass spectrometry, but all of them are based on the principles outlined above. This historically important technology is likely to play a major role in the research phase of the Genesis project when the solar wind samples are returned to Earth for analysis.