Tandem mass spectrometers perpendicular type

I.Szabo, Theoretical analysis of consecutive ion-molecule reactions. I. The mechanisms in a tandem mass spectrometer of perpendicular type. II. The mechanisms in a tandem mass spectrometer of longitudinal type, Int. J. Mass Spectrom. Ion Phys. 3, 103-129, 169-188(1969). 

It is therefore important to avoid transfer of translational energy during the charge-exchange process. This can be done in a tandem mass spectrometer of perpendicular type, and therefore this type will be the only one that will be considered in detail in this chapter. 

Fig. 3. Tandem mass spectrometer of perpendicular type used at Stockholm. The ions A move in mass spectrometer. 4 in a vertical plane and then cross the collision chamber. The reaction products (the ions B) are extracted from the collision chamber at right angles to the direction of the ion beam A and are analyzed by mass spectrometer By which is placed in a horizontal plane. It therefore discriminates against secondary ions which have acquired appreciable downward momentum from the ions A. Radii of mass spectrometer, 18 and 25 cm, respectively.

Tandem mass spectrometers of perpendicular type have been built at Stockholm/ " San Diego/" " Birmingham/ " " Strassbourg/ and Baltimore. Figures 3 and 4 show the two mass spectrometers at Stockholm. 

The selection rules obviously break down if the charge exchange takes place at a very small distance between the colliding particles. In this case, however, transfer of translational energy will also probably take place. As the study of charge-exchange mass spectra in a tandem mass spectrometer of perpendicular type discriminates against such processes, the breakdown of the selection rules is probably without importance for our purposes. 

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