Recent result of gyrotron operation in NIFS Satoshi Ito, Takashi Shimozuma, Yasuo Yoshimura, Hiroe Igami, Hiromi Takahashi, Masaki Nishiura, Sakuji Kobayashi, Yoshinori Mizuno, Kota Okada and Shin Kubo EPJ Web of Conferences, 87 (2015) 04013 Published online: 12 March 2015 DOI: 10.1051/epjconf/20158704013