General Information

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All NSLS-II Beamlines

X-Ray Powder Diffraction (XPD)

Scientific Scope

X-ray Powder Diffraction (XPD) is a damping wiggler beamline at sector 28-ID that offers the ability to collect structural data at high energies (30 - 70 keV), offering exceptional diffraction capabilities such as fast (sub-second) readout rates and high angular resolution on the same instrument. The key scientific goals are to structurally characterize materials at the frontier of complexity, whether the frontier is nanostructure, heterogeneity, or in situ environments. XPD will carry out powder diffraction and PDF/total scattering measurements from a wide range of functional materials.

XPD addresses future scientific challenges in areas such as hydrogen storage, CO2 sequestration, advanced structural ceramics, catalysis, and materials processing. Such materials of high technological value often are complex, nanostructured, and heterogeneous. The scientific grand challenge is to obtain robust and quantitative (micro)structural information, not only in the ground state at ambient conditions, but also in situ or in operando with varying temperature, pressure, magnetic/electric/stress field, chemical environment, etc. The beam size is adjustable to match the graininess and heterogeneity scales above the micron scale.

Beamline Description

Energy Range Wavelength Range Resolution Flux Focused Beam Size
30 - 70 KeV 0.17-0.41 Å ΔE/E ~ 10-3 - 2x10-4 ≈ 8 x 1012  p/s 500 μm (vert) x 50 μm (horiz)

XPD is designed to operate two independent branch lines simultaneously. In the main branch (XPD-1), the upstream endstation hosts a three-circle diffractometer fitted with a flat scintillator panel (16-inch field of view, 200 micron pixels) detector, a 10x15mm2 photon-counting detector (130 micron pixels) and a high-resolution detector bank (8 channels with analyzer crystals) to cover most powder diffraction measurements. A robotic sample changer and a wide range of sample cells (furnaces, cryostats, flow cells, etc.) are available.

The second endstation (XPD-2, not in use yet) will accommodate more elaborate/complex setups: large pressure cells, non-routine reaction chambers, combined spectrometry, gas handling, user-defined specific devices.

The side station (not in use yet) will operate at fixed high energies (39, 64 or 75 keV), optimized for total scattering measurements over a large Q range. The combination of XPD-1 with this XPD-2 complementary parallel-operation station dedicated to high-Q, pair distribution function studies will permit determination of both long- and short-range structures. 

Beamline Schematic

beamline schematic