Scattering/Diffraction

These techniques make use of the patterns of light produced when x rays are deflected by the closely spaced lattice of atoms in solids and are commonly used to determine the structures of crystals and large molecules such as proteins.

When a crystalline sample is illuminated with x-rays, the x-rays are scattered (diffracted) into very specific directions with various intensities. Detectors are used to measure this “diffraction pattern,” which is then processed by computers to deduce the arrangement of atoms within the crystal.

Hard x-rays have wavelengths comparable to the distance between atoms. Essentially everything we know about the atomic structure of materials is based on results from x-ray and neutron diffraction. From advanced ceramics to catalysts, from semiconductor technology to the frontiers of medicine, and from new magnetic materials and devices to framework compounds used to sequester radioactive waste, crystallography using hard x-ray diffraction techniques at synchrotron radiation facilities plays a crucial role in our ability to understand and control the world in which we live.

The scattering of x-rays from protein crystals is the most powerful method of determining the three-dimensional structure of large biological molecules (macromolecules). Because macromolecules are large and flexible, their crystals tend to be small, imperfect, and weakly diffracting. In many cases, the intensity, small beam size, and collimation of a synchrotron beam is vital for successful results.

Soft x-ray scattering techniques employ the excitation of electrons in relatively shallow core energy levels (100–2000 eV) to probe the electronic structure and other properties of various kinds of matter. The sample is illuminated with monochromatic soft x-rays, and the scattered photons are detected over a small angular range. In the elastic scattering mode, one measures the speckle diffraction pattern. In the inelastic mode, the scattered photons are passed through a spectrometer and analyzed.

BL17-2

The beamline 17-2 end-station is currently under construction. This beamline will support simultaneous SAXS/WAXS, XRD, and optical pump x-ray probe measurements. The scientific focus is targeted to take advantage of the high brightness anticipated from the micro-focused beam, with an emphasis on in-situ experiments with demanding time resolution. The beamline will have multiple detectors available and configurable by the beamline staff including a suite of area detectors including an Eiger 1M, Eiger 2 500k, and Eiger 4M.

BL13-3

Beam line 13-3 utilizes a spherical grating monochromator (SGM) on an elliptical polarized undulator (EPU) operating in the photon energy range from 230 eV to 1700 eV with full polarization control (linear vertical/horizontal and circular left/right) covering the C, O, F K-edges, 3d transition metal L-edges, and 4f rare-earth element M-edges.

BL11-3

Beam line 11-3 is a fixed energy (12.7 keV) wiggler side-station dedicated primarily for wide angle x-ray scattering (WAXS). BL11-3 is equipped with a two-dimensional Rayonix MX225 CCD area detector. Supports sample-to-detector distances of 80-550 mm. There are sample environments available for both transmission and grazing incidence geometries. Sample heating is available for both single sample transmission and grazing incidence geometries.

BL10-2a

Beam line currently closed for upgrade.

Beam line 10-2 is a wiggler-based source that splits time between the front hutch (BL10-2a), instrumented for wide-angle X-ray scattering, and the rear hutch (BL10-2b), instrumented for X-ray spectroscopy with a focus on in-situ, time-resolved catalyst characterization.

BL6-2a

Beam line 6-2a is a wiggler end-station that can be configured for tender x-ray x-ray emission spectroscopy (instrumentation in commissioning use).

BL2-1

Beam line 2-1 is a dedicated thin film/powder diffraction and reflectivity station. It is equipped with a Huber 2-circle goniometer and a high-resolution crystal-analyzer detector. There are several different types of sample stages to cater to a broad user-base including a motorized xyz stage, a capillary spinner, a "wet" liquid sample stage, and an Anton-Paar furnace (25-900 ºC). Data acquisition is performed using SPEC, with SPECPlot GUI interface (in-house diffractometer control, peak fitting and plotting software).

BL1-5

Beam line 1-5 is a bend magnet end station with a programmatic split between small angle x-ray scattering (SAXS), wide angle x-ray scattering (WAXS), as well as simultaneous SAXS/WAXS. BL1-5 is equipped with two area detectors: Dectris Pilatus 1M (SAXS) and Dectris Pilatus 100K (WAXS). The beamline is available in two standard configurations: 1- and 3-meter sample to SAXS detector distances. The WAXS detector is typically capable of reaching a minimum q value of 1.2 Å-1 for either of the configurations.

BL4-2

Beam Line 4-2 is a permanent experimental station for small-angle X-ray scattering and diffraction (SAXS) techniques dedicated to research in structural biology and biophysics. The station provides state-of-the-art experimental facilities for structural studies on biological material such as nucleic acids, proteins, protein assemblies, virus particles, biological fibers as well as lipid membranes and membrane-protein/DNA complexes.

Subscribe to Scattering/Diffraction