The findings, which defy expectations and theory, could help scientists deliberately induce the high levels of damage needed to study extreme states of matter or ward off damage in samples they're trying to image. The results were reported this week in Nature Photonics.
The ultra-bright X-ray laser pulses of the Linac Coherent Light Source at SLAC National Accelerator Laboratory can be used to strip electrons away from atoms, creating ions with strong charges. The ability to interact with atoms is critical for making the highest resolution images of molecules and movies of chemical processes.
Credit: Greg Stewart/SLAC National Accelerator Laboratory
Specialized equipment known as the CAMP chamber, pictured here, played a key role in advanced research at SLAC's free-electron laser, the Linac Coherent Light Source. A new paper details experiments with CAMP that observed a record supercharged state in xenon atoms. The equipment was on loan to SLAC through a collaboration with the Max Planck Society Advanced Study Group.
Credit: Brad Plummer/SLAC National Accelerator Laboratory
While the powerful X-rays of LCLS inevitably destroy the samples being studied, delaying damage – even for millionths of billionths of a second – can prove critical in producing detailed images and other data.
"Our results give a 'recipe' for maximizing the loss of electrons in a sample," said Daniel Rolles, a researcher for the Max Planck Advanced Study Group at the Center for Free-Electron Laser Science in Hamburg, Germany, who led the experiments. "For instance, researchers can use our findings if they're interested in creating a very highly charged plasma. Or, if the supercharged state isn't part of the study, they can use our findings to know what X-ray energies to avoid."
Just as a stretched guitar string can vibrate and sustain a note, a specific tuning of the laser's properties can cause atoms and molecules to resonate. The resonance excites the atoms and causes them to shake off electrons at a rate that otherwise would require higher energies.
While it is common knowledge that triggering resonances in atoms will affect their charged states, "it was not clear to anybody what a dramatic effect this could have in heavy atoms when they are being ionized by a source like LCLS," Rolles said. "It was the highest charge state ever observed with a single X-ray pulse, which shows that the existing theoretical approaches have to be modified."
The team had previously used a laser facility in Germany to expose various atoms and molecules to pulses of ultraviolet light, and was eager to use the higher-energy LCLS for further studies.
"The LCLS experiment pushed the charged state to an unprecedented and unexpected extreme – more than doubling the expected energy absorbed per atom and ejecting dozens of electrons," said Benedikt Rudek from the Max Planck Advanced Study Group, who analyzed the data.
In addition to creating or avoiding supercharged plasma states in experiments, Rolles said the "dramatic change" caused by resonance in the absorption of X-ray energy could someday be exploited to improve the resolution of images captured in LCLS experiments.
"Most biological samples have some heavy atoms embedded, for instance," Rolles said, and in some experiments, avoiding the resonance trigger might prevent rapid damage to those atoms.
The researchers have since done similar LCLS experiments involving the heavy element krypton and molecular systems that contain other heavy atoms, said Artem Rudenko of Kansas State University, who led a recent follow-up experiment.
The team's precise measurements were made possible by a sophisticated experimental station built by the Max Planck Advanced Study Group in Germany. In total, the equipment weighed about 11 tons and was shipped to SLAC in 40 crates. It stayed at LCLS for three years and was used in more than 20 experiments ranging from atomic and molecular physics to material sciences and bio-imaging.
"Reassembling this machine at LCLS within one month and then commissioning it and doing a science experiment in only seven days was an absolutely incredible feat," said Rolles.
The research team included scientists from 19 research centers, including: Max Planck Advanced Study Group and several Max Planck institutes, PNSensor GmbH, Technical University of Berlin, Jülich Research Center, University of Hamburg and Physikalisch-Technische Bundesanstalt in Germany; SLAC and Western Michigan and Kansas State universities in the U.S.; University of Pierre and Marie Curie and National Center for Scientific Research in France; and Kyoto and Tohoku universities in Japan.
LCLS is supported by DOE's Office of Science.
SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the U.S. Department of Energy Office of Science. To learn more, please visit www.slac.stanford.edu.
DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Andy Freeberg | EurekAlert!
No compromises: Combining the benefits of 3D printing and casting
23.03.2018 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
Intelligent wheelchairs, predictive prostheses
20.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
24.04.2018 | Information Technology
24.04.2018 | Earth Sciences
24.04.2018 | Life Sciences