Ceramic Materials As Mirrors For Synchrotron Radiation

Abstract The radiation resistance of silica and silica -based mirrors to synchrotron radiation isrelatively low compared with that of a number of ceramic materials, of which silicon carbide has been studied most extensively, although other materials such as the hafniumcarbides and nitrides have generally better X -ray reflective properties. The polishabilities of various types of silicon carbide, having microstructures which range from very homogeneous to a coarse porosity have been investigated, as well as that of onetype of titanium nitride. All the materials are capable of being polished to a very high degree, and surface finishes of a few tenths of a nanometre peak to valley have been attained.Introduction It is now well established that the performance of vitreous silica as a synchrotronmirror substrate is limited by radiation damage. Large radiation doses lead to a progressive shrinkage of the surface layer of the mirror relative to the bulk, and to progressively increasing concave curvature of the reflecting surface. The strain mismatchbetween