COMPACT FREE-ELECTRON LASER-BASED ON AN EXACT CIRCULAR ELECTRON STORAGE-RING

An optimized scheme of the photon storage ring (PhSR) is discussed in this paper. The electron storage ring is of 0.15 m orbit radius composed of a normal conducting magnet. Calculation of the gain and the ohmic power loss suggest that the lasing of 10 mum wavelength is feasible at 10 A accumulated beam current. The growth rate is so large that saturation occurs in a few revolutions. The PhSR features a continuous injection without disturbing the lasing. In this sense PhSR belongs to linac driven FEL, but the lasing condition is determined by the storage ring.