Design and Performance of the Compact YAG Imaging System for Diagnostics at GMCA Beamlines at APS

A compact YAG (Chromium Doped Yttrium Aluminum Garnet - Cr4+:YAG) imaging system has been designed as a diagnostic tool for monochromatic x-rays emanating from the first 'Hard' x-ray dual-canted undulator at the Advanced Photon Source at Argonne National Laboratory. This imaging system consists of a flat YAG crystal, right angle prism/mirror, video camera and monitor. A flat YAG crystal with a diameter of 10 mm has been installed in vacuum and positioned downstream of the monochromator of the insertion device beamline. Another 20 mm diameter YAG crystal has been installed in vacuum after the horizontal deflecting mirrors of the second insertion device beamline. CCD cameras are mounted in air close to the window of the vacuum ports to image the fluorescence of the YAG crystals. An additional 25 mm diameter YAG crystal has been used for K-B (Kirkpatrick-Baez) mirror focusing and beamline alignment. These YAG imaging systems have greatly facilitated beamline commissioning as well as sample alignment to the x-ray beam in the macromolecular crystallography endstation. An overview of the optics design, mechanical design and the performance of these devices will be presented in the paper