SIX AND A HALF MILLION FRAMES PER SECOND – WITH THIS IMPRESSIVE FRAME RATE, SPARTA WILL BE AVAILABLE FROM MID 2021. THIS DEVELOPMENT IS MADE POSSIBLE BY THE SUPPORT OF THE INVESTITIONS- UND FÖRDERBANK HAMBURG.
SPARTA is based on the AGIPD detector chips developed by a consortium led by DESY for the European X-ray laser European XFEL. The performance is unique in the world: 352 images in burst mode at a frame rate of up to 6.5 MHz are buffered so that data sets with the highest temporal resolution are available for subsequent analysis.
“While AGIPD is optimized for the unique requirements of the European XFEL, SPARTA will make the advantages of this technology available to every laboratory,” explains CEO Dr. Julian Becker. To this end, for example, the entire cooling technology and readout electronics will be reduced in size. While AGIPD at the XFEL has a total weight of more than half a ton, SPARTA will have a weight of less than ten kilograms, depending on the desired detector size.
Like X-Spectrum’s successful LAMBDA detector line, SPARTA will also be available in different sensor sizes. A single detector module consists of 128×512 pixels with a pixel size of 200 µm. The dynamic range is impressive: From the detection of single photons up to 1011 photons per second per detector, the X-ray quanta in the range 3-13 keV are cleanly converted into pixel data. And SPARTA is also suitable for harder radiation: The high-Z version extends the range up to 100 keV.
X-Spectrum will be the only vendor to use the AGIPD sensor. This makes SPARTA the best platform for real high-speed X-ray images in your laboratory. “With its technical specifications, SPARTA is complementary to our LAMBDA detectors. SPARTA excels at extremely high speeds, LAMBDA delivers the highest spatial resolution”, Julian Becker sums up.
With the support of the Investitions- und Förderbank Hamburg, the growth of X-Spectrum can be long-term consolidated by expanding the product range. X-Spectrum GmbH is a spin-off of the DESY research centre at the Hamburg site and currently offers 14 highly-qualified employees an exciting and secure job in an innovative environment.
Lithium-rich layered oxides (LLROs) are promising cathode materials for better rechargeable batteries for electric vehicles. They are plagued by a phenomenon called voltage fade, however: When these batteries go through series of charge–discharge cycles, their voltage fades, and with it the amount of energy it can hold and later release for use. An international team led by the University of California, San Diego, has uncovered how this process occurs at the nanoscale. Combined measurements at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL) in the USA and the PETRA III synchrotron source at the DESY research centre in Germany revealed that a mobile network of nanoscale defects forms in the LLRO material during charging, with dislocation density increasing upon repeated charging. These dislocations dramatically alter the local lithium environment and contribute to the voltage fade. Based on their findings, the team devised a method to recover the original high voltage functionality: Heat-treating the cathode materials eliminated most of the defects and restored the original voltage.
The team uncovered the formation of the dislocations using in situ 3D Bragg coherent X-ray diffractive imaging (BCDI) on nanoparticles made of LLRO and of a classical layered oxide for comparison. The BCDI technique enabled them to directly image the interior of the nanoparticles during battery charging – under operating conditions and at nanoscale resolution. The measurements at PETRA III were conducted using a LAMBDA detector, whose small pixel size proved crucial to the success of the experiment: “In a coherent experiment, we measure interference patterns called speckles,” explains co-author Michael Sprung, scientist in charge of the P10 Coherence Applications beamline at PETRA III. “To successfully conduct such a BCDI study, the speckles need to have a certain minimum size with respect to the pixel size of the detector. In this case, they needed to cover at least five pixels.” The pixel area of 55 µm by 55 µm of the LAMBDA detector is nearly a factor of 2 smaller than that of conventional detectors. “This small pixel size was crucial to actually carrying out the experiment at all, due to restrictions of the minimum reachable beam size at the diffractometer setup,” says Sprung.
Nucleation of dislocations and their dynamics in layered oxides cathode materials during battery charging
Nature Energy 3(8), 641–647 (2018)
Catalysts based on metal nanoparticles play an important role in energy conversion and environmental technologies. Their high catalytic efficiency is attributed to their large surface-to-volume ratio and their high number of low-coordination sites, such as edges, which can decrease kinetic barriers between reactants. A key factor influencing the reactivity is the interaction between the reactants and the catalyst, which is closely linked to structural changes of the catalyst itself. Indeed, several studies have reported changes of the overall shape or size of nanocatalysts during catalytic processes. Using measurements at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL) in the USA and the PETRA III synchrotron source at the DESY research centre in Germany, an international team led by Sogang University in Korea has now observed a strong distortion of the crystal lattice at the edges of metal nanocrystals during catalysis. The results identified the edges as the active sites underlying the catalytic activity at the atomic scale.
The team studied the heterogeneous catalytic oxidation of methane on platinum nanocrystals as an example process. Their in situ Bragg coherent X-ray diffractive imaging (BCDI) measurements at PETRA III were performed using a LAMBDA detector, whose small pixel area of 55 µm by 55 µm – about half the one of conventional detectors – enabled the BCDI experiment to be carried out in the first place. This high spatial resolution allowed the team to observe a strong contraction at the edges of the nanoparticles during adsorption of the oxygen. The strain further increased when the methane was introduced and continued during the oxidation of the methane. After the catalytic process was completed, the nanoparticles returned to their original state. As the team demonstrated with their innovative BCDI study, reaction mechanisms obtained from in situ strain imaging provide important insights for improving catalysts and designing future nanostructured catalytic materials.
Active site localization of methane oxidation on Pt nanocrystals
Nature Communications 9, 3422 (2018)