REFLECTIVITY CHARACTERISTICS OF WALL MATERIALS IN THE SYNCHROTRON-RADIATION RANGE

We have carried out measurements of the power reflectivity of wall materials, such as isotropic carbon, C/C composite materials, silicon carbide (SiC), molybdenum (Mo), tungsten (W) and SUS-316, in the wavelength range from 10 to 790 mu m. Molybdenum and tungsten have shown high reflectivities close to 100% in the present wavelength range, while B4C-coated graphite and SiC have shown poor reflectivities less than 40% at a wavelength of less than 400 mu m. Temperature dependence of power reflectivity has also been examined for both the carbon materials and metals. Among them, reflectivities of C/C composite material SUS-316 and SiC have been almost independent of temperature up to about 1000 K. In the cases of B4C-coated graphite, molybdenum and tungsten, appreciable temperature dependencies of reflectivity have been observed, surpassing the theoretical prediction. Reasons for the discrepancy are discussed.