NSLS-II Biomedical Beamlines for Macromolecular Crystallography, FMX and AMX, and for X-ray Scattering, LIX: Current Developments

We present the current status of development of the two macromolecular crystallography (MX) beamlines, FMX and AMX, and the X-ray scattering beamline LIX, at the National Synchrotron Light Source-II (NSLS-II) [1]. Together, FMX and AMX will cover a broad range of use cases from serial crystallography on micron sized crystals, to very large unit cell complexes, to rapid sample screening, e. g. for the always-hard-to-grow membrane proteins and for ligand binding studies. The LIX beamline will support a variety of X-ray scattering measurements for studies on proteins in solution, lipid membranes and biological tissues. We have performed Synchrotron Radiation Workshop (SRW) [2] and Shadow[3] simulations to help select optimal methods to modify the size of the beam easily and smoothly at both FMX and AMX. The very low emittance of the NSLS-II storage ring and the resulting low divergence of the X-ray beam, as well as the long optical path lengths in the photon delivery systems lead to stringent requirements e. g. for vibrational stability and mirror quality. We discuss beamline design considerations addressing these challenges, such as combining mirror optics with compound refractive lenses (CRLs).