The theoretical analysis of the hard X-ray block-structure supermirror.

We present an analytical study to provide guide lines to design a block structure hard X-ray supermirror. The block structure supermirror is a kind of layered structure consisting of several "blocks" of multilayer of different d-spacing to obtain broad energy bandwidth response. This structure has been widely applied in X-ray telescopes because it is easy to fabricate. To examine the propagation of X-rays in a supermirror structure, further simplified approximation of Kozhevnikov's theory has been developed. The supermirror structure is described by a structure function. The spectral function of the structure, which is the Laplace transformation of the structure function, turns out to be proportional to the reflectivity profile against X-ray energy. By analyzing the expression of the spectral function, we found the reflectivity of the supermirror could be smooth due to the box-car shaped spectral function if the d-spacing and layer number of each block is arranged with appropriate constraints.

[1]  Seiji Takahashi,et al.  New design concept of multilayer supermirrors for hard x-ray optics , 1999, Optics & Photonics.

[2]  David L. Windt,et al.  IMD—software for modeling the optical properties of multilayer films , 1998 .

[3]  P. Gondoin,et al.  XMM-Newton observatory. I. The spacecraft and operations , 2001 .

[5]  Roland Diehl,et al.  COMPTEL observations of Ti-44 gamma-ray line emission from Cas A , 1994 .

[6]  David Smith,et al.  Development of the HEFT and NuSTAR focusing telescopes , 2006 .

[7]  C. Morawe,et al.  Design and fabrication of depth-graded X-ray multilayers , 2002 .

[8]  Yoshiharu Namba,et al.  Hard x-ray telescope to be onboard ASTRO-H , 2010, Astronomical Telescopes + Instrumentation.

[9]  Martin C. Weisskopf,et al.  Chandra X-ray Observatory (CXO): overview , 1999, Astronomical Telescopes and Instrumentation.

[10]  Jingtao Zhu,et al.  Determination of the evolution of layer thickness errors and interfacial imperfections in ultrathin sputtered Cr/C multilayers using high-resolution transmission electron microscopy. , 2011, Optics express.

[11]  Takashi Okajima,et al.  Multilayer coated thin foil mirrors for InFOCuS , 2000, Astronomical Telescopes and Instrumentation.

[12]  Fengli Wang,et al.  Design of X-ray super-mirrors using simulated annealing algorithm , 2006 .

[13]  Yoshiharu Namba,et al.  Development of a multilayer supermirror for hard x-ray telescopes , 1998, Optics & Photonics.

[14]  Eberhard Spiller,et al.  Characterization of multilayer coatings by X-ray reflection , 1988 .

[15]  A. Szentgyorgyi,et al.  Design of grazing-incidence multilayer supermirrors for hard-x-ray reflectors. , 1995, Applied optics.

[16]  Roland Diehl,et al.  COMPTEL observations of 44Ti gamma-ray line emission from Cas A , 1994 .

[17]  K. Yamashita.  Development of Pt/C multilayer supermirrors for hard X-ray optics , 2004 .

[18]  Igor V. Kozhevnikov,et al.  Design of X-ray supermirrors , 2001 .