Accurate measurements of intrinsic scattering from window materials by use of a vacuum camera

Abstract

The intrinsic scattering from eight window materials commonly used at synchrotron facilities has been evaluated in the range 0.07 <q< 4 nm−1by the use of a vacuum camera. Poly(oxydiphenylene-pyromellitimide) film, a polyimide film widely used as a window material for vacuum chambers, gave rise to two peaks atq= 0.8 and 4 nm−1. Poly(ether-ether-ketone) gave no Bragg peaks, although the background scattering was relatively high over the entireqrange. When natural mica, synthetic mica, quartz glass, beryllium, silicon nitride and silicon carbide were compared, synthetic mica showed the lowest scattering in the range 0.6 <q< 5 nm−1, indicating that it is the most suitable window material for thisqrange.