SELF-AMPLIFIED SPONTANEOUS EMISSION AT WAVELENGTHS OF 20 AND 40 MU-M FROM SINGLE-BUNCH ELECTRON-BEAMS

The high-brightness single-bunch electron beams of a 38-MeV L-band linac have been used for free-electron laser amplifier experiments to investigate self-amplified spontaneous emission at wavelengths of 20 and 40 mum. At a charge of electrons in a bunch of 28 nC and a pulse length of about 30 ps the intensities of radiation measured have been 5 and 100 times those of the incoherent spontaneous emission estimated at wavelengths of 20 and 40 mum, respectively. The characteristics of the radiation are discussed for developing intense pulsed light-sources.