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In this paper experimental measurement of a W-band gyrotron travelling wave amplifier (gyro-TWA) which is upgraded to operate at a high output power and wide frequency band will be presented. The gyro-TWA based on helically corrugated interaction region and cusp electron beam source can output a maximum power of ∼5 kW at its centre frequency of ∼94 GHz with an instantaneous frequency bandwidth of...
The design and experiment of an upgraded W-band gyrotron travelling wave amplifier (gyro-TWA) based on a helically corrugated interaction region is presented. The upgrade of the input coupler, output window, corrugated output mode converter enabled a measured output power of a few kWs from the gyro-TWA with an unsaturated gain of up to 40 dB and a 3 dB frequency bandwidth of at least 5.5 GHz.
Two designs of fundamental mode rectangular to circular waveguide TE10 to TE11 mode converter are presented. The waveguide transitions are optimized for operation as an input coupler on a 372 GHz gyro-TWA for Dynamic Nuclear Polarization (DNP) enhancement of NMR imaging. A T-junction input coupler and a multiple hole directional coupler were optimized for operation between 360–384 GHz. The T-junction...
The components of a W-band gyro-TWA including input coupler, output window, corrugated output mode converter, pulsed power system and water-cooled beam dump are being upgraded to achieve an output power of 5 kW and a high pulse repetition rate of 2 kHz for cloud radar applications. Latest results of the W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented.
In this paper gyrotron travelling wave amplifiers (gyro-TWAs) based on helically corrugated interaction regions will be presented. Their operating principle and the first experiment in X-band will be reviewed. The present experiment in W-band using a cusp electron beam source with the capability of a high pulse repetition frequency of 2 kHz will also be presented. The design and performances of the...
The design of two fundamental mode rectangular to circular waveguide mode converters are presented. The waveguide transitions are optimized for operation as an input coupler on a 372 GHz gyro-TWA for Dynamic Nuclear Polarization (DNP) enhancement of NMR imaging. A T-junction input coupler and a multiple hole directional coupler were optimized for operation between 360–384 GHz. The T-junction coupler...
Latest developments of a gyrotron travelling wave amplifier (gyro-TWA) with a helically corrugated waveguide and a cusp electron gun for operation over a bandwidth of 90–100 GHz at a high pulse repetition rate (5 kHz) are presented. Performance upgrades of the input coupler, pulsed power system and beam collector with water-cooling capability were realized for the high power wide band gyro-TWA.
Latest development and experimental study of a W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented. With an input seed signal from an 1.5 W, 90–96 GHz solid state source a gain of 27 dB was measured from the experiment. The bandwidth of the gyro-TWA was measured to be at least 5 GHz.
Micro-reentrant square cavities operating at high order modes have been demonstrated to be a viable solution for the realization of millimeter wave klystrons. However, the excitation of the required high order mode is a challenging task. The realization and measurement of a novel coupler for high order mode cavities is proposed.
Theoretical calculation, numerical simulation and experimental development of a W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented. The cusp gun generated a 40 keV, 1.5 A axis-encircling electron beam. The maximum output of the gyro-TWA was predicted to be 5 kW with a 3 dB frequency bandwidth of 90–100 GHz and a saturated gain of 37 dB. The latest experimental...
A W-band gyrotron travelling wave amplifier (gyro-TWA) with a cusp electron gun and a helically corrugated waveguide is presented. The large orbit electron beam from the cusp gun interacts resonantly with an ideal eigenwave existing in the interaction region based on the cyclotron resonance maser instability. When driven by the 40 keV, 1.5 A electron beam the amplifier was simulated to output a maximum...
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