Mass spectrometer, especially for the analysis of insulators

摘要

In a mass spectrometer having an ion gun 10 for directing an ion beam onto the surface of a sample 12, so that said sample 12 emits secondary ions, having a detector 18 for the secondary ions and directing means 20a, 25a, for directing the secondary ions onto the detector, a specific energy bandwidth can be defined on the basis of the energy distribution of the secondary ions with respect to the maximum of the energy distribution. The energy region of the mass spectrometer which can be analysed can be expanded, according to the invention, to at least double the specific energy bandwidth by means of expansion devices which are coupled to the directing means. Using the expansion devices, the pass bandwidth of an energy filter belonging to the directing means can be enlarged in that the resolution and the mean energy of the pass band are increased. The expansion means can also increase the maximum energy of a quadrupole mass filter which can be analysed, especially by modifying the length of the electrode elements of the mass filter and/or by modifying the frequency of an alternating voltage which is supplied to these electrode elements. <IMAGE>