Optics upgrades at the APS beamline 20-BM

Recently, beamline 20-BM has been upgraded with new optics. A large bent cylindrical focusing mirror has been installed to provide an intense focused beam. It is designed to operate over the energy range 2.7–30 keV, and features a novel Al2O3/Pt coating. When operated near 2.6 mrad, the Pt coating provides good reflectivity up to 30 keV. The Al2O3 overlayer minimizes the influence of the Pt M and L edges. The second upgrade that is in progress is the development of longer KB mirrors. A prototype bender has achieved a focus of about 2.5 μm using a 300 mm long mirror. Analysis of the focal spot indicates that the size is dominated by the slope errors of the mirror, and can be further reduced if these are minimized by better mirrors or by using differential coating methods.