RF linacs

Fig. 15.4. High energy beamline featuring an RF linac with 12 resonators. The ion source and analyzer magnets are on the left. The final energy magnet is on the right...

An analogous project (CLIO) is being studied at Orsay (66). The RF-Linac will be built specially for FEL operation, with an adjustable energy E = 30-65 MeV. A wavelength range 1 -15 Mm is expected to be covered in the first instance, with later extension to 50 Mm. Some of... 

Radio-frequency linear accelerators (rf linacs) A linear accelerator that employs radio frequency (rf) cavities for electron acceleration. The particles are accelerated in cylindrical cavities that reqitire a high power soitrce for the rf fields. The rf fields in these cavities may be either traveling or standing waves. In the case of traveling wave conflguratiorts, which are most often employed for electron accelerators, the phase velocity if the rf fields must be synchronized with the desired electron velocity. 

The resmgence of interest in the concept that began in the mid-1970s followed two paths. The term free-electron laser was coined in 1975 by John Madey to describe an experiment at Stanford University that used an electron beam from a radio-frequency hnear accelerator (rf linac). This experiment produced stimulated emission in the infrared spectrum at a wavelength of 10.6 /um using an electron beam from a radio-frequency hnear accelerator (rf Unac). 

FIGURE 8 Schematic illustration of a rf linac-driven free-electron laser oscillator [from H. R Freund and G. R. Neil, Free-Electron Lasers Vacuum Electronic Generators of Coherent Radiation, Proc. IEEE, vol. 87, pp. 782-803,1999]. 

The limitations that storage rings, rf linacs, and mi-crotrons impose on free-electron laser design stems from restrictions on the peak (or instantaneous) currents that may be obtained and that limit the peak power from a free-electron laser. High peak powers may be obtained by using induction linacs, pulse line accelerators, or modulators that produce electron beams with currents rang-... 

---