The diffraction efficiency of the new VGD VLS grating (900l/mm) was measured along the VGD profile, at Metrology beamline at SOLEIL for the photon energy range between 100eV and 1600eV. The measured results are presented below, compared to the calculation.

 The quantitative good agreement between the measured and calculated results shows the high quality of the grating. We also measured the 2nd order diffraction efficiency in order to know how the 2nd order intensity is suppressed. For lower photon energy, 170 degrees deviation angle was chosen, and for higher photon energy, 175 degrees deviation angle was chosen, which are the same geometries as our monochromator.