Optical Performance of the GM/CA-CAT Canted Undulator Beam lines for Protein Crystallography

A new macromolecular crystallographic facility developed by GM/CA-CAT is operational at the Advanced Photon Source (APS). The facility consists of three beamlines: two lines based on the first 'hard' dual canted undulators and one bending magnet beamline. The ID lines are operational, and the BM line is being commissioned. Both insertion device (ID) beamlines are independently tunable over a wide energy range. The inboard ID lines have been upgraded with a new insertion device to provide enhanced performance for MAD phasing experiments near the selenium and bromine K-edges. The ID line monochromators' crystals are indirectly, cryogenically cooled for improved performance and reliability. Focusing is achieved by long bimorph mirrors in a Kirkpatrick-Baez geometry. This paper describes the design of the beam lines and the optical characterization of the mirrors and monochromators