The metrology laboratory at the Swiss Light Source SLS is responsible for measurements and quality control of the optical components, which are used at the beamlines. The optical components are typically reflective optical elements, thus mirrors, they diffract and focus the synchrotron light to the endstations where the experiments take place. The optics are used from the spectral range infrared over visible, VUV to the hard x-ray range. High quality of the optics is essential for aberration free focusing, high photon flux or high resolving power.
The measurements of those optics is a challenge and requires advanced measurement technology and an appropriate environment. Important are in particular a high temperature stability, low mechanical vibrations in combination with clean room environment. The SLS metrology laboratory is located in a cleanroom class 10000. The long trace profiler LTP to measure figure errors is located in a separate hutch with a class 1000 clean room. The temperature and ground vibrations are permanently monitored and archived. The air conditioning provides a temperature stability better +/-0.1 K per day. The typical vibration level is below the VC-E level i.e. the maximum velocity amplitude of the terz spectrum is less than 3 µm/s. Roughness measurements can be performed with a Zygo NewView 5010 profiler. The achievable vertical resolution is better than 0.1 nm, the maximum field of view about 2 x 3 mm. The LTP is a one-dimensional slope measurement device for optics up to 1.5 m length. The resolution is about 0.1 µrad, the dynamic range +/- 5 mrad. The Zygo Verifire ATZ is a Fizeau interferometer with 100 mm usable aperture and zoom.