Jelonnek J, Aiello G, Avramidis K, Franck J, Gantenbein G, Grossetti G, Hesch K, Illy S, Jin J, Kalaria P, et al. From W7-X towards ITER and beyond: Status and progress in EU fusion gyrotron developments. In: Proceedings of 2015 IEEE International Vacuum Electronics Conference, IVEC 2015. ; 2015.