Avramidis KA, Ioannidis ZC, Aiello G, Bénin P, Chelis I, Dinklage A, Gantenbein G, Illy S, Jelonnek J, Jin J, et al. Towards a 1.5 MW, 140 GHz gyrotron for the upgraded ECRH system at W7-X. Fusion Engineering and Design [Internet]. 2021;164.