Development of multilayer mirrors for space-based astronomical X-ray optics.

X-ray reflectivity of single layer coated X-ray mirror is confined to small grazing angles (< 1°) grazing incidence X-ray telescopes usually are bulky and have large focal lengths in trade of effective area which is expensive for a space based telescope. Critical angle for total external reflection of a mirror varies inversely with the energy of the incident photon. This practically limits the possibility of making an X-ray telescope sensitive to higher energy X-rays (<10keV<inline-graphic></inline-graphic>). Use of multilayer mirrors makes it possible to operate the instrument at higher angles and also significantly improves the high energy sensitivity (80 keV). Fabricated W/B4C<inline-graphic></inline-graphic> multilayer mirror provides a peak reflectivity of 19% at first Bragg peak (2.3°) when tested with 8.047 keV X-rays. Multi-wavelength reflectivity analysis of W/B4C<inline-graphic></inline-graphic> multilayer mirror from 9 to 16 keV is presented with a discussion on applications of multilayer mirrors in high energy astronomy. [ABSTRACT FROM AUTHOR]