Supermirror design for Hard X-Ray Telescopes on-board Hitomi (ASTRO-H)
Maeda, Yoshitomo; Ishida, Manabu; Kunieda, Hideyo; Haba, Yoshito; Okajima, Takashi; Awaki, Hisamitsu; Ishibashi, Kazunori; Miyazawa, Takuya; Furuzawa, Akihiro; Tawara, Yuzuru; Yamauchi, Shigeo; Tamura, Keisuke; Miyata, Yusuke; MorI, Hideyuki; Uesugi, Kentaro; Suzuki, Yoshio; HXT Team
Japan, United States
Abstract
We designed depth-graded multilayers, so-called supermirrors, with platinum/carbon (Pt/C) layer pairs for the Hard X-Ray Telescope (HXT) that was on-board the sixth Japanese X-Ray Astronomy Satellite Hitomi (ASTRO-H). The HXT has multinested thin foil optics, and the grazing angles of the x-ray mirrors are 0.07 to 0.27 deg. Supermirrors for HXTs are designed to provide a broad energy response (up to 80 keV) for astronomical requests. Under practical boundary conditions, we establish a block method applying empirical rules to maximize the integrated reflectivity. We fabricated Pt/C supermirrors using a DC magnetron sputtering system. The reflectivity of the mirrors was measured in a synchrotron radiation facility, SPring-8. We describe the design method for the supermirrors and our results.