A 10-minute read
The European Synchrotron Radiation Facility (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 responsible scientist at the Materials Science Beamline ID11.
Jonathan is currently using an EIGER2 X CdTe 4M detector to work on high-energy diffraction experiments. During an online video call, he told us a bit about his work at the ESRF and his first impressions of our CdTe detector.
DECTRIS: What are your personal scientific interests?
Jonathan Wright, responsible scientist at ESRF Beamline ID11: Over time, I have acquired a strong interest in “method development”, which refers to the scientific possibilities that synchrotrons, X-rays, and detectors provide. Every couple of years at the ESRF, there is a technical advancement or improvement that allows users to analyze samples in greater detail - or even work on projects that were previously impossible. Working with a variety of user groups, all of whom bring different samples and fascinating problems to the beamline, is a highlight for me. We collaborate to push the limits of the emerging methods and adapt them to the problem at hand.
The upgrade of the ESRF machine has brought us many benefits in terms of emittance, coherence, and brilliance, and it also brought us a new X-ray detector! I am looking forward to using this new setup to work on even more challenging experiments.
What experiments conducted at the ID11 do you find most fascinating?
Jonathan: We work on high-energy X-ray diffraction experiments, ranging from fundamental physics (arrangement of atoms) to applied problems (stress and strain of components). One of the most intriguing aspects of high-energy X-rays is that the beam will pass through dense samples: allowing researchers to see inside metals, for example.
No surprise, then, that a lot of our research is in the field of metallurgy. Many of our studies are carried out on polycrystalline or multigrain samples. Using a piece of metal as an example, we know that there are several single crystals inside - maybe 10, 100, 1,000, or even 10,000. What is mesmerizing is how the crystals work together and interact as a group. Let’s say you squeeze a piece of metal; it will bend and deform at some point. Personally, I’m fascinated by the mapping of strain distributions within crystals, as well as the ways in which strain is transferred between different crystals in the space, which ones fail first, and why one crystal deforms before another.
Grain mapping is, of course, just one example of what can be done at the beamline. In fact, one of the things I like best about the ID11 is the ability to experiment with a wide range of scientific issues; this would not be possible on a standardized beamline that is designed for a single technique.
What made you choose our EIGER2 X CdTe 4M for your beamline?
Jonathan: Before the ESRF upgrade, we were using a CCD detector. This was a state-of-the-art technology 10-15 years ago, but over time, our needs have changed. This DECTRIS detector, in comparison to the CCD detector, can count individual photons, has a higher dynamic range and much higher frame rates (we are now, in my estimation, 50 times faster), and has no readout noise. These are significant improvements for us.
We were especially impressed by the speed of the detector; we actually had not expected it to run as fast as it does. I also like the possibility of this detector’s measuring zero photons, which is something we’d never been able to do before (with CCDs). When measuring diffraction data, for example, this is useful; Bragg spots are measured, and 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 is now generated, which is qualitatively different and better data for us.
We have actually started running user tests in the last few weeks, and all of them have worked out well - the users are very pleased with the results. This detector is particularly well-suited for high-energy applications, including X-ray diffraction in general.
The DECTRIS EIGER2 X CdTe 4M in action at ESRF Beamline ID11
How does the EIGER2 X CdTe 4M run in practice?
Jonathan: Something we really like is when a detector is 100% reliable - meaning that it does not keep shutting down halfway through, that the data are accurate, and that we don’t have to worry about making difficult corrections. Just last week, the EIGER2 X CdTe 4M was running at maximum speed (500 frames per second) for the majority of the week, and it performed very well, without any issues.
What is your experience with DECTRIS in general?
Jonathan: DECTRIS is a business that is quite academically-oriented, rather than just commercial, which is something I very much respect. DECTRIS makes excellent detectors for us that meet the synchrotron’s requirements, and I greatly appreciate that. Personally, I admire how much work your company puts into growth - you are always looking for ways to change and contribute to scientific breakthroughs. It’s fascinating to observe the progress of a spin-off company from the Paul Scherrer Institut (PSI), which has a long and distinguished history.
Jonathan comes from England, where he studied Chemistry and earned his PhD in the field of neutron scattering. He became a PostDoc at the ESRF after conducting experiments there during his studies, and he has been living and working in France ever since.