Comment to the paper: 'Seeded quantum FEL at 478 keV' AIP Conf. Proc.   'Light at Extreme Intensities' 1462 173-176 (2012)'
  We criticize the thesis exposed the paper 'Seeded quantum FEL at 478 keV' AIP Conf. Proc. 'Light at Extreme Intensities,' 1462 173-176 (2012), which presents the possibility of producing gamma rays at 478 KeV by means of a seeded quantum FEL driven by an electron beam at 125 MeV, current I=40 A, interacting with an infrared laser. We show that, in the case analyzed, the FEL Pierce parameter has a value two orders of magnitude less than what claimed in the paper in question, overturning the conclusions of the analysis. 
Vittoria Petrillo
physics.acc-ph quant-ph