High power broadband CARM amplifier
The simulation of an efficient, broadband cyclotron autoresonance maser (CARM) amplifier operating at a 4MW output power level is presented and discussed. The amplifier is based on a high current accelerator capable of generating a ∼35A pencil electron beam at an accelerating voltage of 450kV. The u...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2004
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| Summary: | The simulation of an efficient, broadband cyclotron autoresonance maser (CARM) amplifier operating at a 4MW output power level is presented and discussed. The amplifier is based on a high current accelerator capable of generating a ∼35A pencil electron beam at an accelerating voltage of 450kV. The use of a beam trajectory modeling code has enabled optimisation of the beam transport system, with results showing a laminar beam profile and transverse velocity spread imparted via beam transport reduced to ∼3%. The low velocity spread was achieved without use of beam scraping, and therefore values presented for the interaction efficiency are a direct reflection of the overall system efficiency. A full 3D numerical model of the CARM amplifier was constructed within the PIC (particle-in-cell) code KARAT taking into account electron beam parameters derived from simulation and experiment. At a frequency of 12 GHz numerical simulations demonstrate 37dB gain and an interaction efficiency of 17%. In addition, a viable amplification bandwidth of 9 - 13GHz is apparent amounting to some 27% detuning from the centre frequency with a minimum gain and efficiency of 25dB and 10% respectively at the boundaries of the amplification band. This primary resonance coupled with the amplification bandwidth gives excellent correlation with the beam-wave dispersion character. |
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