Integrated free-electron laser schemes

The integrated-FEL concept is proposed as an alternative approach for the discrete compact-FELs [1]. In the proposed integrated-FEL, the accelerator and the wiggler are integrated for the sake of compaction. Two examples of integrated-FEL schemes are presented here briefly in order to demonstrate the FEL-integration concept: a) A functional integration scheme is shown in fig. 1. Two electron beams are sharing the same wiggler in this integrated-FEL scheme. A low-energy electron beam (e.b.1) undergoes a ubitron-oscillator interaction and produces high-power microwave radiation. This power is fed to the rf linac which accelerates another electron beam (e.b.2) to a relativistic energy. The high-energy e.b.2 is injected to the same wiggler and interacts with much shorter wavelength than e.b.1, probably in the infrared regime. A considerable overhead reduction in this integrated-FEL system could be the elimination of the external if-source for the linac. b) A volume integration is demonstrated in fig. 2. This integrated-FEL scheme combines a microtron accelerator and a circular wiggler [2]. The electron beam is accelerated as in a microtron, but in its outer arc it is subjected to a circular wiggler field. The wiggling elec-