Parametric optimization for an x-ray Free Electron Laser with a laser   wiggler
  In this paper we optimize the experimental parameters to operate a Free Electron Laser with a laser wiggler in the Angstrom region. We show that the quantum regime of the Self Amplified Spontaneous Emission (Quantum SASE) may be reached with realistic parameters. The classical SASE regime is also discussed and compared with the quantum regime. 
R. Bonifacio, N. Piovella, and M.M. Cola