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To meet the increasing demand of X-ray beamlines for bioscience research, we have designed two high-performance, side-branch, asymmetric-cut curved crystal monochromator (ACCM) beamlines to fully utilize the sideway output of the superconducting wiggler SW6 at NSRRC. Each of these two beamlines (BL13A and BL13C) collects 1 mrad of the radiation fan in the horizontal direction, one centered at 3 mrad and the other at 4 mrad away from the central line of the wiggler output. The newly designed ACCMs are capable of energy scanning from 12 keV to 14 keV and offer good performances in terms of flux, resolution and stability. The ACCMs are designed and built in-house, combining efficient cooling and bending mechanisms in a compact unit that allows precise adjustments on a goniometer assembly. The bender is specially designed with symmetrically driven piezo-actuators that minimize center displacement during bending. Both direct and indirect cooling methods were tested; the former using Ga/In directly under the beam footprint and the latter using both sides of the crystal clamping area for cooling. Performance of the beamlines employing both cooling methods has been measured. The indirect cooling method provides 4.9 × 1010 photons/sec through a pair of 100 μm slits (H × V) with energy resolution of 5.3 × 10-3 (ΔE/E) at 12.7 keV. Higher energy resolution in the 10-4 range can be achieved by adjusting the horizontal source fan or the crystal radius at the expense of flux. The direct cooling method provides 1.4 × 1010 photons/sec through a pair of 100 μm slits (H × V) with energy resolution of 1.2 × 10-3 (ΔE/E) at 12.7 keV. The FWHM of the focused beam profile in the indirect cooling mode is 800 × 109 μm (H × V), and 800 × 283 μm (H × V) in the direct cooling mode with some horizontal tail, the latter being larger due to influence of the Ga/In layer on the crystal shape. Cooling efficiency is excellent in the direct cooling mode, in which the performance stabilizes in a few seconds after the photon shutter is opened, and in the indirect cooling mode the performance stabilizes in a few minutes. At present, both SW6 side-branch beamlines are ready for uses’ bioscience research: BL13C for crystal screening, drug design, and high-resolution structural study, and BL13A for scattering experiments on biomaterials such as membranes. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Two high-performance asymmetric-cut curved crystal monochromator (ACCM) side-branch x-ray beamlines have been designed to fully utilize the sideway output of a superconducting multipole wiggler (SMPW) source for protein crystallography research. Each of the two ACCM beamlines collects 1 mrad of radiation in the horizontal direction. One of them is located at 4 mrad and the other at 3 mrad away from the centerline of the radiation fan of the wiggler output. These two beamlines will deliver photon flux, through a 100 μm pinhole, of greater than 1×1011 photons/sec with energies from 12 keV to 14 keV and resolution (ΔE/E) of 1.5×10-3 for standard monochromatic crystallography experiments. A Rh-coated, water-cooled vertical focusing mirror is placed upstream of the ACCM to simplify the energy tuning mechanism and to reduce the heat load of the crystal by cutting off the photon beams at energies above 15 keV. Considering that existing ACCM designs with bender either have insufficient cooling efficiency or are difficult to manufacture, we designed a special cost-effective ACCM that comprises a crystal plate affixed to a water-cooled, bendable Cu substrate, where heat conducts through a paste-like alloy. With this design, the monochromator will provide high photon flux and resolution while maintaining excellent stability. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We are constructing a high-throughput biological crystallography beamline BL13B, which utilizes the radiation generated from a 3.2 Tesla, 32-pole superconducting multipole wiggler, for multi-wavelength anomalous diffraction (MAD), single-wavelength anomalous diffraction (SAD), and other related experiments. This beamline is a standard double crystal monochromator (DCM) x-ray beamline equipped with a collimating mirror (CM) and a focusing mirror (FM). Both the CM and FM are one meter long and made of Si substrate, and the CM is side-cooled by water. Based on detailed thermal analysis, liquid nitrogen (LN2) cooling for both crystals of the DCM has been adopted to optimize the energy resolution and photon beam throughput. This beamline will deliver, through a 100 μm diameter pinhole, photon flux of greater than 1011 photons/sec in the energy range from 6.5 keV to 19 keV, which is comparable to existing protein crystallography beamlines from bending magnet source at high energy storage rings. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]