MASTIF: Mass analysis of secondaries by time-of-flight technique. A new approach to secondary ion mass spectrometry

A new approach to surface studies by time-of-flight secondary ion mass spectrometry is proposed. The time-of-flight technique is implemented in an unconventional way utilizing a continuous-probing beam. The ‘‘birth’’ moment of the secondary ion is fixed by the detection of secondary electrons emitted when a probing-beam particle strikes the surface. Multichannel mass identification of secondary ions is thus possible using a low-intensity continuous-probing beam, which permits one to study fragile and extremely thin (down to few monolayers) objects, sensitive to damage by intense probing beam and high doses. The technique has been applied to thin (30-Å) self-supporting carbon foil, semiconducting material, and the sensitive surface of a microchannel plate.