These silvery components usually gleam in a place that is not visible to the public: they do their work hidden away in a “reformer”. This device converts diesel into fuel gas that drives fuel cells. Such systems power the on-board electrical system in trucks, for example. This helps save power and reduce pollutant emissions. Jülich engineers developed the reformer together with colleagues from the Institute of Energy and Climate Research.
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Mass merchandise? No chance. Series production? Rarely. Tailor-made unique products are routine for Jülich’s engineers and technicians. Together with researchers, they construct and operate devices that did not previously exist. Without these masterpieces, a fair few scientific insights would not be possible.
A black-and-white video transmission flickers slightly out of focus on the screen. It shows a heart-shaped metal box which is iced over. Nothing moves. But then, clouds start to loom behind the box, it is suddenly thrown to one side, and a finger-sized object flies past two armoured cameras. A small hole gapes in the icy metal heart, and white fog oozes out.
To a lay person, it would be difficult to see any sense in this experiment. But one thing is obvious: the metal box has been destroyed. Yannik Beßler is pleased nevertheless. “It just passed its test,” says the engineer from the Central Institute of Engineering, Electronics and Analytics (ZEA-1) observing the heart-shaped masterpiece he developed and constructed. “It’s part of a coolant tank for neutrons. The plan is for it to be built into the most powerful neutron source in the world, the European Spallation Source (ESS) that is currently being constructed in Lund, Sweden,” he explains. The video stream shows a stability test during which the pressure inside the component is continually increased. At a certain point, the strain became too much: the metal burst and a piece was blasted off. “But at 196 °C and a pressure of 200 bar, it was eight times tougher than it needs to be,” explains Beßler, closing the video on his computer. Destroying his work of art several times is part of the creation process. This is the only way Beßler can be sure that the component is sufficiently reliable.
Image above: These silvery components usually gleam in a place that is not visible to the public: they do their work hidden away in a “reformer”. This device converts diesel into fuel gas that drives fuel cells. Such systems power the on-board electrical system in trucks, for example. This helps save power and reduce pollutant emissions. Jülich engineers developed the reformer together with colleagues from the Institute of Energy and Climate Research.
The heart-shaped box – or “cold moderator” to give it its scientific name – is one of many parts tailored by Beßler and his colleagues at ZEA-1 specifically for applications in world-class research. “Scientists obtain products from us that you can’t simply choose and order from a catalogue. Together with the scientists, we develop unique pieces for their specific scientific issues,” says Prof. Ghaleb Natour, director of ZEA-1. In addition to instruments for research with neutrons, these include measuring devices for climate research such as AirLIF, which analyses trace gases in the atmosphere, or prototypes for imaging techniques in medical research. ZEA-1 also contributes to the fuel cells of the energy supply of the future: new components and a special joining technology for materials were developed here.
“The art lies in combining the scientific way of thinking with the creativity of the engineers.”
Prof. Ghaleb Natour
Jülich’s know-how is in demand beyond the campus. “Chopper systems”, for instance, are used all over the globe (see map below): in Chilton (UK), Grenoble (France), Tsukuba (Japan), and Oak Ridge (USA). Choppers are rotating precision instruments that filter and “chop” neutron, X-ray, and light beams. Scientists use them to study highly sensitive samples, for example, in order to understand physical, chemical, or biological processes. What’s so special about Jülich’s systems is that thanks to the contactless magnetic bearing and clever drive technology, the choppers run for years without requiring maintenance – and they do so with extreme precision. “To make something possible that previously did not exist or was viewed as technically infeasible: that’s the area of expertise of our 170 engineers, scientists, and skilled workers.”
When it comes to Yannik Beßler’s moderator, the search for suitable materials was a challenge. “Components for a neutron source have to withstand extreme stresses. In these facilities, neutrons are released from atomic nuclei and then directed towards samples,” says Beßler. This way, new materials can be tested and biological systems investigated in detail for future medicine. Together with other components, the moderator cools and decelerates the high-energy neutrons, which have temperatures of several thousand degrees, so that they can be directed to the samples in a targeted manner. “The neutrons have to be one hundred million times slower. This means that we have to strip them of an enormous amount of energy, which can only be done by cooling the heart down to 250 °C using liquid hydrogen,” explains the engineer. Only very hard and heat-resistant materials such as beryllium, the iron–nickel alloy Invar, or high-strength aluminium can be used for these extreme requirements.
“We ended up using a material used in aircraft construction. An aluminium alloy seemed suitable,” says Beßler. Processing, however, presented a challenge. “In aircraft construction, the alloy is riveted – but we had to weld the seams of the moderator. Welding the alloy was previously viewed as impossible.” Patience and testing was required. The models and components destroyed by testing – which are lined up like organ pipes next to Beßler’s desk – bear witness to this. The solution was a further, softer aluminium alloy that the ZEA experts introduced into the weld seam. “This alloy is a bit more flexible and acts as a kind of glue under the extreme stresses,” according to the engineer. This has made the cold heart extremely tough. Beßler and his colleagues are now in the process of manufacturing the first units for future use at ESS. Before that, the components will be put to the test again: using X-rays, the experts from ZEA will screen each component in order to preclude any hidden flaws. After all, the masterpieces should not have any shortcomings.
It’s not only ZEA-1 that produces small and large masterpieces using the art of engineering: ZEA-2 – Electronic Systems develops electronic and information technology systems in a targeted manner. ZEA-3 – Analytics focuses on new analysis methods for scientific issues. Some institutes on Jülich’s campus also operate their own workshops, which are adapted to the requirements of the individual research fields. “ZEA is usually asked to help with the large and complex experiments,” says Natour, “because we can provide the complete package, ranging from project planning and simulations to feasibility studies, software development, and manufacture.” One area of expertise is in particularly high demand at the workshop run jointly by the Jülich Centre for Neutron Science and the Peter Grünberg Institute: “We specialize in the smallest of precision work. Although we are also capable of manufacturing larger components, the trend at our institutes is in the other direction: tailor-made, delicate components,” explains the head of the workshop, Jens Schnitzler. The components can be for measuring instruments at neutron sources or the mounts securing material samples. “The challenge for us is usually that we have to manufacture very small parts from a very tough material because the experimental conditions are often harsh: high pressure or high vacuum, large voltages or extreme temperatures.”
Schnitzler has a whole cabinet full of materials for a variety of applications, including polyimide (PI, a plastic used in aeronautics), tantalum, and tungsten – each of them heat-resistant, very tough materials. Their processing is accordingly challenging. “We can’t do anything without a state-of-the-art collection of instruments,” says the industrial mechanic, nodding towards a giant device. “There are only about 50 of this type of ultrasonic milling machine in all of Germany. We can use it to process unusual materials such as hard metals, ceramics, and glass.” The conventional area of application for this technology is dentistry because ceramic materials for dentures can be processed very precisely with it. The little artworks created by Schnitzler and his team using the milling machine are lined up neatly in a display case. Some of the indentations and channels in the pieces are so delicate and tiny that the engineers can only check their quality using the electron microscope in the nearby Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons.
“Sometimes I come up with new ideas when discovering interesting elements of stage construction.”
Angelina Steier
The worlds into which Angelina Steier has to dive are not quite as tiny. At the Institute of Bio- and Geosciences (IBG-2), she faces challenges of a different nature. The electrical engineer predominantly designs flying experimental set-ups. “Our scientists mainly need mobile measuring instruments which nonetheless have to function precisely,” says the automation specialist.
An example of this is a device which Steier and her colleagues are developing to conduct measurements under special circumstances on a field. A ring with a diameter of 17 m is placed on the field, supplying plants with additional carbon dioxide – a simulation of climate change. The scientists measure the plants within the ring at regular intervals. When the field is harvested, for example, they remove the set-up so that operations are not impeded. Afterwards, they come back and continue measuring. “The challenge is in finding the exact locations of the measuring points again – and we’re talking about high precision on a rough, agricultural terrain. We can only make statements about long-term developments if we measure the exact same points again and again,” says Angelina Steier.
Such set-ups require imagination and creativity. The result is a special piece of art: “For the structure of the ring used to supply the CO2, we combined scaffolding components with support elements from stage construction. Using a retractable measuring arm, the sensors can be moved up and down. The measuring system is placed on the trailer of a tractor so that the sensors can be moved over the field. This way, we cover all three spatial dimensions,” says Steier.
She gets her inspiration from everyday life, for example during visits to the theatre: “Sometimes I have new ideas if I discover interesting elements of stage construction. Or laser sensors like this one,” she says, pointing towards an unremarkable grey box in her office. “They are usually used in the drinks industry, at conveyor belts: they check that crates of beer are actually full. But they can also be used in plant research. After all, what they measure is differences in height,” says the engineer. It sounds surprisingly simple. Sometimes it’s the simple things that help create a masterpiece.
Birgit Pfeiffer
Images: Forschungszentrum Jülich/C. Heßelmann, Forschungszentrum Jülich/Sascha Kreklau, Forschungszentrum Jülich/Ralf-Uwe Limbach, Video: Forschungszentrum Jülich
