Material characteristics of CLEARCERAM-Z HS for use in large diameter mirror blanks

There is growing interest within the Astronomical community in the development and use of very large aperture telescopes which will incorporate the latest advancements in optical materials. Two of the most notable of these large size telescope projects, the Thirty Meter Telescope (TMT) and European Extremely Large Telescope (E-ELT), will use mirror segments in the actively controlled primary mirrors. In this paper we present the results of a material characteristics study on Ohara CLEARCERAM ® -Z HS large diameter blanks which includes data on the CTE, CTE uniformity, residual stress and internal quality targeting potential use in the TMT Primary Mirror Segment Banks.