Source APS Undulator A Monochromators Si <111> and <400> Energy Range (Si <111>) 3.5--13 keV (fundamental) 10.5--39 keV (third harmonic) Energy Resolution (ΔE/E) 2x10-4 (Si <111>) Minimum Spot Size (μm2 FWHM) < 1500 x 3500 (unfocussed) < 60 x 160 (at detector 3.5 m from sample) Angular resolution (μrad2 FWHM) 160 x 190 The heart of the BioCAT facility is the undulator beamline 18 ID located in sector 18 at the Advanced Photon Source. 18 ID is designed to be a very high performance instrument designed for, and dedicated to, the study of partially ordered and disordered biological materials. With its flexible optics and control systems 18 ID can deliver high flux (~1013 photons/s) into small focal spots (< 60 μm (FWHM vertical), < 160 μm (FWHM horizontal)) with low beam divergence making it very well suited for a wide variety of static and time-resolved diffraction and scattering applications with biological systems. The small source size and high flux delivered by the APS and the rapid motion and energy scanning capabilities of the beamline control system makes 18 ID an effective tool for scanning x-ray microprobe applications. For further details on this beam-line, please see Fischetti et al., J. Synchrotron Rad., 11, 399-405. (2004)