Mitja Kelemen joined the team at Microanalytical center as B. Sc. Student in 2011. He manly focused on use of micro-beam fore elemental chemical analysis. With emphasis on biological tissue and samples exposed in fusion reactors. Since 2015 he is employed as an operator of 2 MV tandem accelerator at JSI. Simultaneously he started working on study of effects of surfaces roughness on materials relevant for inner walls of fusion reactors, as part of his PHD thesis. Application of ion beam methods, on various fields, led him to be author or co-author of more than 20 original scientific papers.