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Posted: Oct 26, 2010
Honey, I shrunk the synchrotron
(Nanowerk News) If you say 'synchrotron' to most scientists, they will picture an immense, highly expensive and rather rare facility designed to produce highly intense beams of light, such as the UK's Diamond Light Source that boasts a 500 metre circumference and cost GBP 263 million (EUR 297 million) to build. However, that could soon change, as EU-funded scientists have created a table-top device capable of producing synchrotron X-rays that are as intense as those produced by some of the world's largest X-ray facilities.
The instrument, which is described in the journal Nature Physics, could make it simpler and cheaper to analyse materials in fields as diverse as medicine and aeronautic engineering.
EU support for the work came from the LASERLAB-EUROPE ('The integrated initiative of European laser research infrastructures II') project, which received EUR 10 million under the Research Infrastructures budget line of the Seventh Framework Programme (FP7).
'Each successive generation of X-ray machines has opened up new frontiers in science, such as the first radiographs and the determination of the structure of DNA [deoxyribonucleic acid],' the researchers point out. Today, synchrotrons provide researchers of all disciplines with extremely bright X-rays capable of imaging systems at ever higher resolutions. However, their size and costs mean that there are only a few synchrotrons in the world, and the demand for time using these facilities far outstrips supply.
The new table-top synchrotron, which was developed by scientists in France, Portugal, the UK and the US, works in a similar way to a normal synchrotron, but on a much smaller scale - the entire device is housed in a vacuum chamber that is around 1 metre across.
The researchers note that the X-rays generated by their system have an extremely short pulse length and originate from a very small point in space, resulting in a very narrow X-ray beam. These properties are not easy to obtain from other X-ray sources, so the new system could lead to new developments in advanced X-ray imaging, the researchers suggest. For example, ultrashort pulses could allow researchers to study atomic and molecular interactions taking place on the femtosecond timescale, a femtosecond being one quadrillionth of a second. Meanwhile a narrow X-ray beam reveals the finest details in a sample of material.
'We think a system like ours could have many uses,' commented Dr Zulfikar Najmudin of the UK's Imperial College London, who led the research. 'For example, it could eventually increase dramatically the resolution of medical imaging systems using high energy X-rays, as well as enable microscopic cracks in aircraft engines to be observed more easily. It could also be developed for specific scientific applications where the ultrashort pulse of these X-rays could be used by researchers to "freeze" motion on unprecedentedly short timescales.'
Dr Najmudin and his team obtained their results using one of the most powerful lasers in the world. 'High power lasers are currently quite difficult to use and expensive, which means we're not yet at a stage when we could make a cheap new X-ray system widely available,' he explains. 'However, laser technology is advancing rapidly, so we are optimistic that in a few years there will be reliable and easy to use X-ray sources available that exploit our findings.'
Commenting on the results of the study, Imperial College London's Dr Stefan Kneip says: 'We have taken the first steps to making it much easier and cheaper to produce very high energy, high quality X-rays. Extraordinarily, the inherent properties of our relatively simple system generates, in a few millimetres, a high quality X-ray beam that rivals beams produced from synchrotron sources that are hundreds of metres long.
'Although our technique will not now directly compete with the few large X-ray sources around the world, for some applications it will enable important measurements which have not been possible until now.'