In situ surface profiler for high heat load mirror measurement

Abstract

High heat loads on optical components in next-generation synchrotron radiation sources will require the use of sophisticated methods to prevent surface distortion that would degrade the intrinsic source brightness. In some cases it is desirable to be able to measure the mirror figure under actual operating conditions in ultrahigh vacuum. We propose to modify the standard long-trace profiler configuration to enable scanning profiler measurement of mirrors under actual high heat load conditions. The modification entails the use of a penta prism on a translation stage inside the vacuum chamber, with the optical head mounted outside the chamber. This configuration is similar to the original pencil-beam interferometer system developed by von Bieren, but it contains a number of modifications that enhance its accuracy.