Advertisement

The European synchrotron, the ESRF, recently underwent a major upgrade and received eight DECTRIS EIGER®2 detectors (seven with cadmium-telluride sensors and one with a silicon sensor) for its new Extremely Brilliant Source (EBS). Beamline scientists at the ESRF were very excited about working with the new detector series, and among them was Dr Jonathan Wright, who is the scientist in charge at the materials science beamline, ID11.

Jonathan is using an EIGER2 X CdTe 4M detector for a variety of high-energy diffraction experiments. The ability to experiment with a wide range of scientific issues is one of the things that Jonathan likes the best about the ID11; this would not be possible on a standardised beamline that is designed for a single technique.

Consequently, Jonathan has a strong interest in method development , which relies on new possibilities that synchrotrons, X-rays and detectors provide. At the ESRF, every couple of years, there is a technical advancement or improvement that allows users to analyse samples in greater detail or even work on projects that were previously impossible. Collaborating with a variety of user groups, all of whom bring different samples and fascinating problems to the beamline, is a highlight for Jonathan.

The upgrade of the ESRF machine has brought many benefits in terms of emittance, coherence, and brilliance, and it has also provided new X-ray detector.

Before the ESRF upgrade, the ID11 beamline was equipped with a CCD detector. This was a state-of-the-art technology 10 15 years ago, but over time, the needs of the beamline have changed. The new X-ray detector, EIGER2 X 4M, can count individual photons, has a higher dynamic range, much higher frame rates and no readout noise. These are significant improvements for us , says Jonathan. I was especially impressed by the speed of the detector; I actually had not expected it to run as fast as it does , he continues.

In Jonathan s opinion, one of the other benefits of the detector is its ability to measure zero photons, which is something that was not possible with a CCD detector. When measuring diffraction data, for example, one can see intense Bragg spots, while in between the Bragg spots a large portion of the pixels will measure zero most of the time. Instead of 2D pictures, a 3D stream of events can be now generated,

A DECTRIS EIGER2 X CdTe 4M at the ESRF beamline ID11

which is qualitatively different and provides better data.

The ID11 is ideal for many research topics, one of them is metallurgy.

One of the most intriguing aspects of working with high-energy X-rays is that the beam will pass through dense samples: allowing researchers to see inside metals, for example. Not surprisingly, a lot of the research done at ID11 is in the field of metallurgy. Many of their studies are carried out on polycrystalline or multigrain samples. For example, a piece of metal contains a multitude of single crystals 10, 100, 1000 or even 10,000. But how do they hold together, how do they interact as a group, and how do they deform upon applied force? Jonathan is not only fascinated by these questions, but also with ways to answer them: strain distribution mapping within crystals, as well

as the ways in which strain is transferred between different crystals in space.

This, of course, is not where the story ends the ID11 beamline covers many more high- X-ray energy applications, and accommodates a variety of users and samples. Jonathan is looking forward to using the new setup to work on even more challenging samples.

Our favourites are X-ray powder diffraction and pair distribution function. Discover yours at www.esrf.fr/ID11.

DECTRIS Tel +41 56 500 21 00 E-mail info@dectris.com www.dectris.com

The Dectris EIGER2 X CdTe 4M in action at the ESRF s ID11 beamline.