Can direct field-evaporation of doubly-charged ions and post-ionisation from singly-charged state co-exist ?


Can direct field-evaporation of doubly-charged ions and post-ionisation from singly-charged state co-exist ?

Ganetsos, T.; Mair, A. W. R.; Bischoff, L.; Akhmadaliev, C.; Aidinis, C. J.

A tin liquid metal ion source (LMIS) containing ~ 13% Pb has been studied. From a careful examination of the mass spectra of the source it is concluded that post-ionisation is a most probable mechanism for the formation of Pb++ ions. In the case of tin, however both Sn+ and Sn++ appear to form by direct field-evaporation. This view is supported by energy deficit measurements on the Sn+ and Sn++ beams . Our results for Pb++/Pb+ agree with those of Komuro (1983) with a pure Pb source. The reason for this is understandable and is related to the similarity between the evaporation fields of Sn and Pb. For the sake of completeness we also present measurements of the energy spread of the Sn++ and Sn+ beams.

Keywords: tin liquid metal ion source; liquid metal cone; mass spectra; field-evaporation; post-ionisation

  • Lecture (Conference)
    49th International Field Emission Symposium (IFES 04), 12.-15.07.2004, Seggau castle, Graz, Austra
  • Surface and Interface Analysis 39(2007)2-3, 128-131

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Publ.-Id: 9772