World's most powerful X-ray laser launched in Hamburg
02 September 2017
The world's most powerful X-ray laser has begun operating at a facility in the north German city of Hamburg, where scientists will attempt to recreate the conditions deep inside the sun and produce film-like sequences of viruses and cells.
The 3.4km-long machine, called the European X-ray Free Electron Laser (XFEL), generates extremely intense X-ray flashes to be used by researchers from all over the world, promising breakthroughs in medicine, biology, chemistry, energy, and information technology.
The flashes are produced in underground tunnels, and will allow scientists to map atomic details of viruses, film chemical reactions, and study the processes in the interior of planets.
In effect, it acts as a high-speed camera that can capture images of individual atoms in a few millionths of a billionth of a second. Unlike a conventional camera, though, everything imaged by the X-ray laser is obliterated – its beam is 100 times more intense than if all the sunlight hitting the Earth's surface were focused onto a single thumbnail.
With the help of specialised instruments, these X-rays enable completely new insights into the atomic details and extremely fast processes of the nano world.
Scientists will use these X-ray flashes to, for example, map the three-dimensional structure of biomolecules and other biological particles, and do so faster and with greater details than has ever been possible.
Furthermore, single snapshots of particles produced with the X-ray laser can be drawn together to create "molecular movies" to study the progress of biochemical and chemical reactions.
Other applications include material science with the development of new materials and substances, and optimisation of storage media for computers, among other fields.
The facility, housed in a series of tunnels up to 38 metres underground, will allow scientists to explore the architecture of viruses and cells, create jittery films of chemical reactions as they unfold and replicate conditions deep within stars and planets.
Scientists are already engaged in a fierce competitive bidding process to be among the first to get time on its six beamlines.
''The laser is the biggest, and the most powerful, source of X-rays ever made,'' said Olivier Napoly, a member of the French Atomic Energy Commission who helped build the complex.
XFEL is the world's third major X-ray laser facility – projects in Japan and the US have already spawned major advances in structural biology and materials science. The European beam is more powerful, but most significantly has a far higher pulse rate than either of its predecessors.
''They can send 100 pulses out per second, we can send 27,000,'' says Robert Feidenhan'l, chairman of the European XFEL management board.
This matters because to study chemical reactions or biological processes, the X-ray strobe is used to capture flickering snapshots of the same system at different time-points that can be stitched together into a film sequence.
At XFEL, scientists will be able to collect data at a far quicker rate and miss less of the action between shots.
Allen Orville, who runs the XFEL hub at the UK's Diamond Light Source, is among the first users who will start data collection in two weeks' time. Orville is focused on understanding the molecular mechanics of how enzymes make antibiotics, such as penicillin, with the ultimate goal of being able to develop new ways to produce antibiotics in the future.
Previously, scientists have been able to measure the crystal structure of the beginning and end-products. But, according to Orville, this is like trying to understand an Olympic high-jump contest based on pictures of the athlete on the bench before the jump and lying on the mat afterwards.
''We're trying to get the enzyme at the top of that high bar,'' he said. ''We hope we'll be able to see the very complex reaction cycle including some of the short-lived intermediates that have never been seen before.''
Another planned experiment will aim to reveal the process by which molecules capture light and turn it into energy during photosynthesis. ''You might use that as an input to make an artificial device to do the same,'' said Feidenhan'l. ''That's my dream.''
The centrepiece of the facility is the world's longest – a mile long superconducting linear accelerator, designed to provide the energy needed to generate X-ray flashes a billion times brighter than the best conventional radiation sources. The tunnel's temperature is kept at 2C above absolute zero.
The electrons are then beamed between a series of magnets that send them on slalom-like path, where at each wiggle they emit X-rays, which coalesce into an intense laser beam.
The wavelength of the X-rays is about 0.05 nanometres, comparable to the radius of a hydrogen atom. It hits the target and the resultant scattered radiation, picked up by detectors, reveals the sample's internal structure – just before it is destroyed.
XFEL will also house a powerful optical laser to go alongside the X-ray gun, which scientists will use to exert extraordinary pressures on materials in order to reproduce conditions similar to those at the centre of the earth or inside the sun – or simply to morph materials into previously unseen configurations.