Visiting the European XFEL, a mega research institute in Hamburg's Metropolitan Region

Mr. Beam

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The European XFEL is the most elaborate experimental research site in Germany: in a 3.4-kilometre-long concrete pipe stretching from Hamburg to Schleswig-Holstein, scientists accelerate electrons to nearly the speed of light. They study materials and molecules with the X-ray flashes created. Our author Urs Spindler ventured into one of the lead-lined experiment hutches to meet Dr Adrian Mancuso, who is in charge of one of the first operational measuring instruments.

Author

Urs Spindler

Photos: Torben Weiss

Dr Adrian Mancuso stops for the first time in the tunnel. The physicist, known just as Adrian to everyone here, gazes into the distance, but the end of the neon-white illuminated concrete pipe is indistinguishable to the naked eye. “I get a fresh impression of the magnitude of our project every time I see this view,” he says. Carried on chest-high posts, a matt metal tube with a diameter maybe the breadth of two fingers vanishes somewhere in the distance. As from a short time ago, 27,000 X-ray laser flashes per second regularly zip through this tube. They make tiny structures visible – in more detail than any other scientific instrument in the world.

A precision instrument the size of an underground railway tunnel

The European XFEL is an international research institute of superlatives: the brightness of the light from the X-Ray Free Electron Laser is comparable to similar projects in the USA and Japan, but the flash frequency is unparalleled. A 3.4-kilometre-long tunnel was drilled for the project from the DESY research centre in Hamburg to the neighbouring region of Schleswig-Holstein – just before the border, the tunnel fans out into five pipes, at the end of which experiment stations examine the structure of bio-molecules, for example. A facility of scientific precision and at the same time Germany's most elaborate experimental station, its subterranean passages were dug out by machines that are normally used in building underground railways.

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In the underground experiment hutch, the X-ray flashes are re-focused and directed into a steel sample chamber.

Adrian Mancuso sits at the end of one of these tunnels. The scientist has been working on the development of his experimental station for just under seven years. “Most people who build a scientific instrument like this only do it once in their lifetime,” says Mancuso. He's followed the call halfway around the world: born in Australia, took a research assignment in Los Angeles after his PhD, then moved to Hamburg.

“Shoot 'em in, blow' em up, measure the pattern“

Mancuso lives in the hip Hamburg district of Altona, his wife Jess is an artist with a studio near their home. “We've settled in well here. I like the beautiful buildings, all the cafés. The people are cool and I can get everywhere on my bike”. Mancuso also cycles back and forth to work between Hamburg and Schenefeld. He's one of those people who are always on the go. A likeable powerhouse, a head shorter than most of his colleagues but definitely the most colourful: a short-sleeved shirt with palm-tree pattern, shorts and smart leather shoes with welted soles. He wore Vans for his last TV appearance.

This is how the X-ray laser works

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  • This is how the X-ray flashes are generated: a laser knocks bunches of electrons out of a piece of metal in the "gun". (simulation: European XFEL)

  • The electrons are accelerated by magnetic fields over a distance of 1.7 kilometres to 99.9999999 percent of the speed of light. They then pass through a resonator made of the heavy metal niobium. For this to work, the equipment has to be cooled to minus 271 degrees Celsius. The metal conducts the electrons with almost no electrical resistance at this temperature. (Simulation: European XFEL)

  • The researchers then force the accelerated electrons into a slalom course using a series of periodically arranged magnets (so-called undulators). The electrons emit the desired X-rays in this process. (Simulation: European XFEL)

  • Most of the facility is underground. The electrons start their journey in the Hamburg district of Bahrenfeld, at the DESY research centre there. DESY is deeply involved in the European XFEL. Behind the high-rise development at Sorter Born, they are divided up among five tunnels that end in the experiment hutches in Schenefeld. (Simulation: European XFEL)

  • Results found by the detectors at the experiment station could look like this: before a molecule is destroyed by the X-ray pulse, it scatters part of the radiation. Scientists can draw conclusions about the molecule's structure from the resulting pattern. This pattern is a simulation, based on the European XFEL logo. (Simulation: European XFEL)

However laid-back, he's one thing above all else: a leading scientist in his field. His team of physicists, engineers and technicians now consists of more than 20 specialists from six continents. “Scientific thinking connects and defines us – much more so than nationality, gender or any other characteristic,” says Mancuso. Their shared workspace is the experiment hutch, a grey container in the large subterranean experiment hall. Embedded in the concrete walls are two-centimetre-thick lead plates to absorb any residual X-rays.

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The researchers are on track time-wise – but there's still a fair amount to do before external scientists could use the measuring instrument.

Behind an airlock of plastic panels, almost the entire team is clustered around the hutch's various stations this afternoon. The X-ray flashes created by the kilometre-long accelerator are re-focused here and directed into a steel sample chamber, where they hit the material to be examined. “Shoot ´em in, blow ´em up, measure the pattern”, Mancuso sums up the process in a broad Australian accent: when bombarded with the X-ray flashes the sample is destroyed. At the next station, the detector, the reflections of the X-ray pulses are measured.

The results will then appear on the neighbouring control room's monitors. The researchers have framed a snapshot of the first beam to reach the end of the tunnel and hung it on the wall. To the layman, the printout looks like the coloured image from a thermal imaging camera. “We don't take photos here,” declares Mancuso – but every image has a mathematical relationship with the sample examined. Many thousands of images can then be used to calculate the shape of a molecule measuring just a few millionths of a centimetre, for example.

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A lot of the experiments are basic research, e.g. for the medical field.

The work done at the European XFEL is basic research, but with many possible applications. For example, scientists are working on revealing the three-dimensional structure of viruses – a basis for the development of medical treatments. Teams from all over the world will be able to use the accelerator from mid-September onwards. The experiment slots were booked solid ages ago – including the night shifts. That makes Mancuso and his work group something like the home team. “My people control the instrument,” he says. But there's still a lot to do before that: technicians are disentangling cables, test runs with low and high voltage current are about to start. And the detector, cooling system and control system are still being tested as well.

Mancuso sits on a table in the control room with his legs dangling. Of course there's still a lot to do, he says, “but if I've done everything right, the team will be able to do most of it on their own now”. Meanwhile, he himself is pondering the future of his instrument: the first upgrades are already planned. Normal enough, in Mancuso's opinion. “For me, science means that you always want to push it a bit further”.

Find out more about XFEL here

www.desy.de and here www.xfel.eu

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