European research activities towards a future DEMO gyrotron J. Jelonnek, G. Aiello, S. Alberti, K. Avramidis, A. Bertinetti, A. Bruschi, J. Chelis, T. Franke, G. Gantenbein, S. Garavaglia et al. (27 more) EPJ Web Conf., 149 (2017) 04007 Published online: 04 August 2017 DOI: 10.1051/epjconf/201714904007