Senf, F.; Bijkerk, F.; Eggenstein, F.; Gwalt, G.; Huang, Q.; Kruijs, R.; Kutz, O.; Lemke, S.; Louis, E.; Mertin, M.; Packe, I.; Rudolph, I.; Schäfers, F.; Siewert, F.; Sokolov, A.; Sturm, J.M.; Waberski, C.; Wang, Z.; Wolf, J.; Zeschke, T.; Erko, A.: Highly efficient blazed grating with multilayer coating for tender X-ray energies. Optics Express 24 (2016), p. 13220-13230
10.1364/OE.24.013220
Open Accesn Version

Abstract:
For photon energies of 1 – 5 keV, blazed gratings with multilayer coating are ideally suited for the suppression of stray and higher orders light in grating monochromators. We developed and characterized a blazed 2000 lines/mm grating coated with a 20 period Cr/C- multilayer. The multilayer d-spacing of 7.3 nm has been adapted to the line distance of 500 nm and the blaze angle of 0.84° in order to provide highest efficiency in the photon energy range between 1.5 keV and 3 keV. Efficiency of the multilayer grating as well as the reflectance of a witness multilayer which were coated simultaneously have been measured. An efficiency of 35% was measured at 2 keV while a maximum efficiency of 55% was achieved at 4 keV. In addition, a strong suppression of higher orders was observed which makes blazed multilayer gratings a favorable dispersing element also for the low X-ray energy range.