Process for operating a time-of-flight secondary-ion mass spectrometer

Abstract

The invention pertains to a process for operating a time-of-flight secondary ion mass spectrometer for analysis of mass spectra, wherein a number of finely structured mass ranges appear in isolation at major intervals, involving the following steps: a) a surface of a material sample is bombarded with primary ion pulses that follow each other at regular time intervals t.sub.z (cycle time), b) the secondary ions of various masses m released from the material sample surface by the primary ions are accelerated to the same energy, c) the mass-dependent time of flight t is measured over a path 1 and the mass is determined therefrom. To increase the resolution and the signal-to-noise ratio the process is characterized in that: d) each primary ion pulse consists of a number of subpulses, e) each subpulse is so narrow that it allows for resolution of the finely structured mass ranges, g) the number n of subpulses is selected so that n.multidot.t.sub.B is smaller than the intervals between the finely structured mass ranges, h) the n subpulse spectra of each finely structured mass range are added up.

Dependencies are inferred from the claim text.