Title :
Experiments of a thermionic gyro-TWA based on a helical interaction waveguide
Author :
He, W. ; Ronald, K. ; Young, A.R. ; Rafferty, E.G. ; Phelps, A.D.R. ; Cross, A.W. ; Whyte, C.G. ; Thomson, J.
Author_Institution :
Dept. of Phys., Strathclyde Univ., Glasgow, UK
Abstract :
Gyrotron traveling wave amplifier (gyro-TWA) experiments based on a helically corrugated waveguide have been undertaken at Strathclyde University for the last few years. In this paper we report our latest experimental results using a longer pulse electron beam of energy 185keV and current 7.5A produced by a thermionic cathode. The coupling between the second harmonic cyclotron mode of the electron beam and the radiation field occurred in the region of near infinite phase velocity over a broad bandwidth. A saturated gain of 24dB which had a 3dB instantaneous bandwidth from 8.4 to 10.4GHz (i.e. 21% relative bandwidth) was measured. The gyro-TWA had a saturated maximum output power of 220kW, corresponding an electronic efficiency of 16%. Good agreement was found between the measured power and the value predicted from nonlinear beam-wave interaction simulations carried out using the 3D particle-in-cell computer code MAGIC.
Keywords :
electron beams; electronic engineering computing; gyrotrons; thermionic cathodes; travelling wave amplifiers; waveguides; 185 keV; 220 kW; 24 dB; 3D particle-in-cell computer code; 7.5 A; 8.4 to 10.4 GHz; MAGIC; gyrotron traveling wave amplifier; helical interaction waveguide; near infinite phase velocity; nonlinear beam wave interaction simulations; pulse electron beam; radiation field; second harmonic cyclotron mode; thermionic cathode; Bandwidth; Cathodes; Cyclotrons; Electron beams; Gain measurement; Gyrotrons; Near-field radiation pattern; Optical coupling; Power generation; Pulse amplifiers;
Conference_Titel :
Microwave and Millimeter Wave Technology, 2004. ICMMT 4th International Conference on, Proceedings
Print_ISBN :
0-7803-8401-6
DOI :
10.1109/ICMMT.2004.1411521
