1. Department of Physics and Astronomy; University of Bologna; Viale Berti-Pichat 6/2 40127 Bologna Italy
2. Elettra-Sincrotrone Trieste; Area Science Park; Strada Statale 14, km 163.5 34149 Basovizza Trieste Italy
3. Department of Engineering and Architecture; University of Trieste; Via Alfonso Valerio 6/1 Trieste 34127 Italy
4. Department of Physics; University of Surrey; GU2 7XH Guildford Surrey UK
5. Department of Electrical and Electronic Engineering; University of Cagliari; Via Marengo 2 09123 Cagliari Italy