Characterization of Pt/C multilayer at 200 keV soft gamma-ray

Imaging observations by means of optics is crucially important, not only for its capability of spatially resolving astronomical objects, but also for its sensitivity superior to non-imaging experiments by orders of magnitude. In order to study feasibilities of reflective optics in soft gamma-ray region, we measured Pt/C multilayer and multilayer-supermirror at 200 keV. Angular dispersion is measured at wide range of incidence angle. The results showed that measured reflectivities agree well with model calculation using tabulated optical constants and roughness measured at 8.4, 30 and 60 keV. Possible configuration of soft gamma-ray telescope is discussed.