XPDF beamline helps first users to uncover atomic secrets of intriguing new material

Diamond’s X-ray Pair Distribution Function beamline (XPDF) I15-1, has recently welcomed its first users.
The first facility of its kind it Europe, XPDF allows scientists to scrutinise the characteristics of a huge range of materials on the atomic scale.
Materials are a key tool for helping society to adapt to challenges as varied as energy supply, global infrastructure and technological progress.
Using the XPDF beamline, scientists will be able to explore how the conformation of atoms inside a material affects its properties on a much larger scale. Scientists can use the facility to analyse the precise distances between atoms within a sample, providing an extensive insight into the arrangement of atoms inside materials.
A group from the University of Oxford were the first to use Diamond’s new beamline, exploiting its advanced capabilities to study an interesting compound that has the unusual property of contracting when it is heated.
Known as ‘negative thermal expansion’ (NTE), this property could have profound implications on engineering infrastructure. There is much demand for materials that do not expand when heated, and NTE materials could have applications in everything from dental fillings to road surface.
The group, led by Professor Andrew Goodwin, used the powerful capabilities on I15-1 to study the X-ray pair distribution function (PDF) of zinc cyanide – a compound that exhibits NTE.
Professor Goodwin said: "I am thrilled that a group of graduate, undergraduate and postdoctoral researchers from our research group in Oxford were able to carry out the first user measurements on the XPDF beamline at Diamond, and the team appropriately included Ali Overy, who is a DPhil student jointly supervised by Dr Phil Chater, beamline scientist on I15-1.”
He explained that the group are aiming to use XPDF to solve the puzzle of how properties on the atomic scale are related to the unusually large NTE effect that zinc cyanide exhibits.
Aside from being a continental first, another remarkable feature of XPDF is the fact that the beamline successfully welcomed their first users just one week after ‘first light’: the moment when synchrotron light is first observed on the beamline. This achievement is an amazing feat on behalf of the dedicated beamline team.
Principal Beamline Scientist, Dr Heribert Wilhelm, said: “Building a new beamline into an operational one was a challenging task. Achieving ‘first light’ and ‘first users’ within a week without disrupting the operational beamline would not have been possible without the diligent commitment of the team and the support groups.
“It was a really exciting moment to see the diffraction and pair-distribution function data appearing on the screen almost simultaneously.”

Professor Trevor Rayment, Physical Science Director at Diamond, said: “I’m delighted that XPDF has proved so successful in supporting its first users – this is an area of research that has real relevance to challenges we face in engineering and, indeed, in our daily lives”.

XPDF in Detail
The importance of understanding local structure is becoming increasingly apparent in a number of disciplines including materials chemistry, solid-state physics, earth sciences and pharmaceuticals. With XPDF, researchers will be able to study the local structure of crystalline, semi-crystalline and amorphous solids and liquids with a speed and robustness which has not, until now, been possible anywhere in Europe.
XPDF is optimised to provide the high X-ray energy, high flux and low background signal which are necessary for quality PDF data. Sample environments will initially focus on high-throughput capillary samples, including variable temperature experiments from 85 K to 1200 K.
The flexibility of the sample station should facilitate the development and installation of more complex transmission geometry sample environments in the near future. Specialised processing software has been developed which will ultimately produce PDF data in real-time at the point of data collection, providing an unparalleled user-friendly X-ray PDF beamline.
XPDF is now in a thorough commissioning and optimisation period, and it expects to have users on a regular basis later this year.

Download the XPDF leaflet here.