Two NSLS-II beamlines for macromolecular crystallography are under construction. The two beamlines, FMX and AMX, are funded by NIH and built by the Photon Sciences Division (PSD) at the Brookhaven National Laboratory. FMX beamline will be a micro-focusing beamline fully taking advantage of the high-brightness qualities of NSLS-II. The objectives are to produce a tunable X-ray beam that can be focused down to 1 x 1 µm2 size with low divergence; and to build a beamline for the most difficult projects in macromolecular crystallography. These projects include small and weakly diffracting crystals, as commonly observed in membrane proteins, or large unit cells, as commonly encountered in large macromolecular complexes. The undulator device will provide X-rays over a wide energy range (5-23 keV). The X-ray optics for the undulator beamline will produce bright, tunable beams in a size range of 1-20 µm. The experimental endstation will be equipped with an advanced pixel-array detector with the best signal-to-noise ratio and fast readout time. The crystal handling/mounting device will also be modern to assure automated, fast specimen delivery.
Conceptual Design of NSLS-II Beamlines FMX and AMX
FMX beamline consists of an IVU21 undulator, Si(111) double crystal monochromator, a secondary source design, and a pair of K-B focusing mirrors in the experimental hutch (Berman, L.E., et al., Nuclear Instruments and Methods in Physics Research, 2011. A469: p. 131-5). A beam size of 1 x 1 µm2 with photon flux at the sample position of ~1013 ph/s is expected based on the design. This predicted flux compares favorably with the performance of established leading micro-focusing beamlines in the world.
AMX beamline will be a highly automated beamline with flexible scheduling and easy access. Operation of AMX will be similar to procedures that have proven to be exceedingly efficient at X29, but will also include increased remote operation capabilities. Rapid access mode with multiple user groups collecting data alternatively in the same time period will be supported at this fast and versatile beamline. The objectives of AMX include supporting challenging projects that require screening of thousands of crystals, such as structural studies of membrane proteins and drug screening projects. Data collection on every crystal brought to the beamline will be possible, as each dataset will only require a few seconds to finish. AMX is designed to produce a highly tunable X-ray beam in the size range of 4-100 µm.
AMX will be a mini-focusing, highly automated and high-throughput beamline. The beamline design includes an IVU21 undulator covering an energy range of 5-18 keV, a Si(111) double crystal monochromator, and a pair of K-B focusing mirrors in the experimental hutch. It is expected to deliver a photon flux of ~1013 ph/s in a focal spot size of 4 x 3 µm2.
The CSB has obtained a Partner User Agreement for FMX/AMX with the Photon Sciences Directorate to assist in construction, commissioning, and operation of the two beamlines. As part of this agreement, 15% of the available beamtime will be allocated to CSB, all of which will be returned to general users through the NSLS-II General User Program. Contact Wuxian Shi for details.
Tentative Timeline of FMX and AMX Design, Construction, Commissioning and Operation