Seeded quantum FEL at 478 keV

We present for the first time the concept of a seeded γ quantum Free-Electron-Laser (QFEL) at 478 keV, which has very different properties compared to a classical. The basic concept is to produce a highly brilliant γ beam via SASE. To produce highly intense and coherent γ beam, we intend to use a seeded FEL scheme. Important for the production of such a γ beam are novel refractive γ-lenses for focusing and an efficient monochromator, allowing to generate a very intense and coherent seed beam. The energy of the γ beam is 478 keV, corresponding to a wavelength in the sub-Angstro/m regime (1/38 A). To realize a coherent γ beam at 478 keV, it is necessary to use a quantum FEL design. At such high radiation energies a classical description of the γ-FEL becomes wrong.