We Must be MAD

摘要

MAD (Multi conjugate Adaptive optics Demonstrator) is an MCAO pathfinder experiment for both Over Whelmingly Large (OWL) 100 m telescopes and ESO VLT 2nd generation instrumentation. MAD's Wave Front Sensor (WFS) employs five thermo-electrically cooled e2v CCD39 - 01 devices operating in two modes: the multi Shack-Hartmann (SH) WFS consists of three CCDs with 80×80 pixels which are read in parallel at up to 400 frames per second delivering a pixel rate of 4.8 Mpix/sec at lowest noise. The Layer Oriented (LO) WFS is constructed with two CCDs of the same type but both detectors are read simultaneously with different frame rates and binning factors using a single FIERA controller. This paper discusses the concept of both SH and LO wave front sensors and gives first performance results from laboratory tests. We report on techniques used to implement and improve clock patterns and the lessons learned during the development phase.