1. Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlarce 39/64, Praha 180 86, Czech Republic
2. Atominstitut, Technische Universität Wien, Stadionallee 2, Wien 1020, Austria
3. MedAustron, Marie Curie-Strasse 5, 2700 Wiener Neustadt, Austria
4. Department of Thin Films and Nanostructures, Institute of Physics of the CAS, Cukrovarnicka 10/112, Praha 162 00, Czech Republic