14 December 1992 The 1 mw, 200 GHz fom-fusion-fem
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Proceedings Volume 1929, 17th International Conference on Infrared and Millimeter Waves; 19291T (1992) https://doi.org/10.1117/12.2298182
Event: 17th International Conference on Infrared and Millimeter Waves, 1992, Pasadena, CA, United States
A 1 MW, cw, Free Electron Maser is being designed for ECRH applications on ITER [1]. The FEM will be tunable over 10% of the central frequency of 200 GHz. Furthermore, experiments at 250 GHz and -later on- 130 GHz are foreseen. The FEM uses a thermionic electron gun and a 2 MeV electrostatic accelerator [2]. The required fast tunability is achieved by variation of the accelerator voltage. The undulator and mmw system are located inside a terminal at a voltage of 2 MV. The terminal is placed inside a steel vessel of 10 m long and q 2.5 m, filled with SF6 at 6 bar. The layout is shown in Fig. 1. After interaction with the mm waves in the undulator, the energy of the electron beam will be recovered by means of a decelerator and a multi-stage depressed collector. This will bring the overall efficiency to a very high level. The voltage for an FEM is much higher than for other high-power mm-wave sources, like gyrotrons and CARMs. However, the main current has to be supplied at a voltage of not more than a few hundred kV. The 2 MV power supply has to deliver the electron-beam current lost during transport, therefore the loss of electrons has to be limited to approximately 20 mA. For this reason and also to enable an efficient energy recovery, a simple straight electron-beam line will be used.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
A. G. A. Verhoeven, A. G. A. Verhoeven, } "The 1 mw, 200 GHz fom-fusion-fem", Proc. SPIE 1929, 17th International Conference on Infrared and Millimeter Waves, 19291T (14 December 1992); doi: 10.1117/12.2298182; https://doi.org/10.1117/12.2298182

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