Spectrometry surface charging

For a-spectrometry, silicon charged-particle detectors (surface-barrier detectors) have been used. They can be used over an extensive range of energies (20 kV-200 MeV). The inherent resolution of these surface-barrier detectors is surpassed only by that of magnetic spectrometers. 

Surface-charging problems can also be minimised by the use of neutral beams to bombard surfaces instead of primary ions, a technique known as fast atom bombardment mass spectrometry (FABMS) [44-47]. A disadvantage of this type of process is that chemical information is limited to a spatial resolution of a few millimetres only, and no information is available on the spatial distribution of specific chemical moieties. 

In Dynamic Secondary Ion Ma s Spectrometry (SIMS), a focused ion beam is used to sputter material from a specific location on a solid surface in the form of neutral and ionized atoms and molecules. The ions are then accelerated into a mass spectrometer and separated according to their mass-to-charge ratios. Several kinds of mass spectrometers and instrument configurations are used, depending upon the type of materials analyzed and the desired results. 

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