1. Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
2. Maria Curie-Skłodowska University, Department of Biophysics, Mass Spectrometry Laboratory, Pl. M. C.-Skłodowskiej 1, 20-031 Lublin, Poland
3. Centre of Physics and Technological Research, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal