High power test of a temperature controlled diplexer for electron cyclotron current drive system

• Published in: Fusion engineering and design 2017-11, Vol.123, p.385-389
• Main Authors: Saigusa, Mikio, Sekiguchi, Kenji, Honzu, Toshihiko, Mori, Junnya, Shozu, Hiroki, Oda, Yasuhisa, Ikeda, Ryosuke, Takahashi, Koji
• Format: Article
• Language: English
• Subjects: Cyclotrons; Diplexer; ECCD; Electrons; Frequency shift; Gyrotron; Heat conductivity; Millimeter wave; Millimeter waves; Nuclear reactors; Pulse duration; Resonant frequencies; Studies; Switching; Temperature dependence; Thermal expansion; Tunable
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2017.03.146

•A high power frequency tunable diplexer by controlling thermal expansion was developed for ECCD systems.•The tunable frequency band is 225 MHz at an operation frequency of 170GHz.•The high power tests of the diplexer have been carried out up to 0.26MW, 100ms at 170GHz. A diplexer to be used as a fast switching device of high power millimeter wave for an electron cyclotron current drive system has been developed. The operation frequency of the device is tunable by controlling the thermal expansion of the cavity using a precision chiller. The tunable range of the diplexer is about 225MHz at the frequency band of 170GHz. The temperature dependence of the resonant frequency shift in the ring resonator diplexer is −3.4 to −3.9MHz/K, which agrees with the theoretical prediction. The switching operation is confirmed up to rf power of 260kW, a pulse duration of 100ms, and a frequency of 170GHz.