Time-of-Flight Secondary Ion Mass Spectrometer
Time-of-Flight Secondary Ion Mass Spectroscopy (ToF SIMS) uses a pulsed ion beam (Cs or microfocused Ga) to remove molecules from the very outermost surface of the sample. It is done with sufficiently low intensity to insure that the molecule chains are not broken into their constituent pieces. The particles removed from the surface (secondary ions) are accelerated into a "flight tube" and their mass is determined by measuring the exact time at which they reach the detector. The exact masses can be calculated with such accuracy that particles with the same nominal mass (e.g. Si and C2H4) are easily distinguished from one another. Mass resolution to 0.00x amu and mass range 0-10,000 amu (e.g. polymers and organic components) can be obtained. The ToF SIMS can detect trace elements and image the chemical distribution on surfaces with resolutions near 0.5 microns.