Precise topographic surface measurements of warm and cold large image detectors for astronomical instrumentation

摘要

This paper describes ESO's surface measurement device for large image detectors in astronomy. The machine was equipped with a sub-micrometer laser displacement sensor and is fully automated with LabView. On the example of newly developed curved CCDs, which are envisaged for future astronomical instruments, it was demonstrated that this machine can exactly determine the topographic surfaces of detectors. This works even at cryogenic temperatures through a dewar window. Included is the calculation of curvature radii from these cold curved CCDs after spherical fitting with MATLAB. In addition (and interesting for calibration of instruments) the micro-movements of the detector inside the cryostat are mapped.