Shaping the optical surfaces of large mirrors made from polycrystalline silicon

Diagnostic mirrors with transparent protection layer for ITER

“…From this point of view, polycrystalline silicon (PCS) is considered to be a promising material for the mirror substrate [4]. The PCS combines significant specific rigidity E/ (E -modulus of elasticity and -unit weight), with a low thermal distortion parameter˛/ , characterized by the ratio of the linear expansion coefficient˛to thermal conductivity (see Table 1).…”