Scientific Scope

XPD is a tunable facility with the ability to collect diffraction data at high x-ray energies (40keV-80keV), offering rapid acquisition (millisecond) and high angular resolution capabilities on the same instrument.

XPD addresses future scientific challenges in, for example, 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.

The beamline is of novel optical design, making use of techniques and instrumentation being pioneered at NSLS (Laue optics and Ge strip array detectors), as well as being matched to the high flux of a full 7m NSLS-II damping wiggler.

In the longer term, the combination with a complementary parallel-operation station dedicated to high-Q, pair distribution function studies will permit determination of both long- and short-range structures.

Beamline Description

XPD is designed to operate two independent branch lines simultaneously. In the main branch, the upstream endstation hosts a three-circle diffractometer fitted with a 1D strip detector and a high-resolution detector bank to cover most powder diffraction measurements. The second endstation accommodates more elaborate/complex setups: large pressure cells, non-routine reaction chambers, combined spectrometry, gas handling, user-defined specific devices. The side station will operate at a fixed high energy (60 or 80keV), optimized for total scattering measurements over a large Q range.