Reflectivity around the gold L-edges of x-ray reflector of the soft x-ray telescope onboard ASTRO-H

We report the atomic scattering factor in the 11.2–15.4 keV for the ASTRO-H Soft X-ray Telescope (SXT) obtained in the ground based measurements. The large effective area of the SXT covers above 10 keV. In fact, the flight data show the spectra of the celestical objects in the hard X-ray band. In order to model the area, the reflectivity measurements in the 11.2–15.4 keV band with the energy pitch of 0.4 – 0.7 eV were made in the synchrotron beamline Spring-8 BL01B1. We obtained atomic scattering factors f1 and f2 by the curve fitting to the reflectivities of our witness sample. The edges associated with the gold′s L-I, II, and III transitions are identified, of which the depths are found to be roughly 60% shallower than those expected from the Henke’s atomic scattering factor.