SNO2 GRAZING-INCIDENCE ANTIREFLECTION FILMS FOR MONOCHROMATIZATION OF SYNCHROTRON RADIATION - DESIGN, PREPARATION, AND CHARACTERIZATION

Grazing-incidence antireflection (GIAR) films are used to suppress electronic reflectivity, while maintaining good nuclear resonant reflectivity to help monochromatize the synchrotron radiation down to the mueV level of energy resolution. Such monochromators will have superior throughput by a factor of 100-500 compared to natural linewidth of individual nuclei. (SnO2)-Sn-119 GIAR films of various thicknesses were designed and fabricated on Pd-coated quartz substrates. The performance of these films was evaluated based on the measurement of off-resonance x-ray reflectivity using MoKalpha radiation and conversion electron Mossbauer spectroscopy. A Pd film was deposited on a quartz substrate at room temperature and was subsequently annealed at 500-degrees-C in an Ar atmosphere at a substrate temperature of 200-degrees-C, SnO2 was sputtered onto the Pd by reactive sputtering in an Ar and O2 atmosphere. Employing quantitative analysis of surface and interface roughness, a series of experiments was also conducted to determine optimal sputtering conditions.