A Low-Energy-Spread Rf Accelerator for a Far-Infrared Free-Electron Laser

TitleA Low-Energy-Spread Rf Accelerator for a Far-Infrared Free-Electron Laser
Publication TypeJournal Article
Year of Publication1993
AuthorsC.AJ van der Geer, R.J Bakker, A.FG van der Meer, P.W van Amersfoort, W.A Gillespie, G. Saxon, M.W Poole
JournalNuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment
Date PublishedOct 1
ISBN Number0168-9002

A high electron current and a small energy spread are essential for the operation of a free electron laser (FEL). In this paper we discuss the design and performance of the accelerator for FELIX, the free electron laser for infrared experiments. The system consists of a thermionic gun, a prebuncher, a buncher and two standard commercial linac sections. The gun is operated with a pulse duration of 280 ps and a bunch charge of 200 pC. After compression to 35 ps by the prebuncher, the bunches are accelerated to 4 MeV in the buncher and simultaneously compressed to 6 ps. The principle of the method is that the order of the electrons is conserved in the buncher, so that the resulting more or less linear energy-phase relationship along each bunch can be compensated effectively against space charge forces and the accelerating field gradient in the linacs, via an appropriate choice of the phase of the rf wave. Behind the linacs an rms energy spread of 0.30% has been measured.



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