Development of manufacture of mirror glass substrate for x-ray timing and polarization observatory

In China, X-ray timing and polarization (XTP) observatory will have a collection area of 9,000 cm 2 at 2~6 keV. The observatory consists of five identical hard X-ray telescopes and ten identical soft X-ray telescopes. The angular resolution is about 1 arcminute of HPD (half-power diameter). Each telescope consists of a large number of mirror segments precisely assembled together. Our development of the mirror glass substrate is presented in this manuscript. These substrates are produced by slumping commercially available thin glass sheets. Here, we report on our work of manufacturing these substrates. The optimization of the slumping procedure is described and optimal procedure parameters are reported. The figure error of slumped glass substrates was measured by a laser scanner and an interferometer with CGH. The measurement demonstrated that the figure error is lower enough for the construction of XTP telescopes.