First non-intercepting emittance measurement by means of optical diffraction radiation interference

Transverse electron beam size measurements are required in order to determine the transverse emittance. In the case of high brightness electron beams produced by high repetition rate linear accelerators, conventional invasive diagnostics cannot sustain the intense power dissipated in intercepting devices. The analysis of the angular distribution of diffraction radiation has been proven to be a competent candidate for non-intercepting measurements of electron beam parameters. In addition, optical diffraction radiation interference (ODRI) has been demonstrated to be superior to the single slit ODR due to its shielding capability against the synchrotron radiation background and the possibility of avoiding complementary diagnostics. This paper reports the first transverse emittance measurement ever performed with the ODRI technique. In addition, the intrinsic non-intercepting and non-disturbing feature of the ODRI method has been checked in our experimental conditions by wakefield calculations.