Surface temperature and slope errors on plane mirrors exposed to high power synchrotron radiation

Abstract

The temperature at the surface and the distortion of plane mirrors made from various materials have been investigated with incident surface power densities of the order of 0.4 W/mm 2 and total powers of up to 170 W. Although the surface temperature could be significantly lowered by increasing the cooling water flow rate, the temperature gradients and the deformation of the surface were found to be independent of the cooling. Si and SiC were found to be much superior to all other samples. Contrary to the theoretical expectations the surface distortion was found to depend not just on the figure of merit for thermal distortions. This is interpreted by taking into account the penetration depth of the radiation emitted by the hard-X-ray wiggler (HARWI) in the 5.3 GeV storage ring DORIS.