| Paper | Title | Page |
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| TUPPH033 | A FEL Amplifier Based on Planar Bragg Waveguides | 393 |
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A planar periodic Bragg structure can be used for wave guiding in the direction transverse to the lattice vector. Open Bragg waveguide can provide high selectivity over the transverse coordinate when its size essentially exceeds wavelength. We study several new schemes of FEL amplifiers based on these structures. In a transverse current amplifier scheme it is beneficial to use a grating with a step of corrugation, that results in the existence of a single low dissipative mode located near defect. The sheet electron beam moves across the waveguide to be resonant to one of partial waves forming the operating mode. Another way is a traditional traveling wave amplifier scheme where electron beam moves along waveguide axis. To increase effective size of operating mode is suggested a structure with regular longitudinal corrugation that couples two partial waves propagating at some angle to the axis to the wave propagating directly along the axis. This wave, which in moving reference frame is transformed into a cut off mode*, is excited by the electrons. Analysis shows rather high gain and efficiency of the novel application schemes with simultaneous discrimination of parasitic modes.
*1. N.S. Ginzburg, A. M.Malkin, N. Yu. Peskov et. al. Improving selectivity of free electron maser with 1D Bragg resonator using coupling of propagating and trapped waves, PR ST-AB 8,040705(2005) |