X-ray Timing and Polarization (XTP) telescope is proposed in China, by using the nested Wolter-I type optical system with large effective area, for the study of high energy physics at the region of 1-30 keV. High reflectance and low stress W/Si multilayers are demanded in the telescope to fulfill the spectral response and ensure the figure quality of the mirrors at the same time. A dedicated cylindrical deposition facility based on direct current magnetron sputtering technique was developed. Using this facility, W/Si multilayers fabricated under different base pressure and working pressure were tested to optimize the sputtering process. The microstructure and stress of W/Si multilayers with different d-spacing (d=2.0 nm-7.0 nm) and thickness ratio of W (ϒ_w=0.3-0.7) were studied. In order to obtain low stress multilayer mirrors, post-deposition annealing was applied on the multilayers and both the effects of temperature and annealing time were studied. Based on these works, a depth-graded W/Si multilayer was deposited on thin cylindrical mirror and the X-ray reflectivity was measured at Beijing Synchrotron Radiation Facility (BSRF).

Date Published: 31 May 2017
PDF: 8 pages
Proc. SPIE 10235, EUV and X-ray Optics: Synergy between Laboratory and Space V, 102350G (31 May 2017); doi: 10.1117/12.2265752

Published in SPIE Proceedings Vol. 10235:
EUV and X-ray Optics: Synergy between Laboratory and Space V
René Hudec; Ladislav Pina, Editor(s)