70 years old research provides solution to 21st century question

10 July 2008 

Research into the understanding of how X-rays interact with matter could lead to the production of more powerful exotic magnets, such as those that will make electric vehicles more efficient and cost effective or those required to develop a new generation of CT scanners. By rekindling an effect first discovered 70 years ago to understand the processes that cause X-rays to be absorbed by matter, a team of scientists led by the University of Warwick, working alongside colleagues at the STFC Daresbury Laboratory in Warrington and the Diamond Light Source in Oxfordshire, have uncovered subtle details about electrons that determine properties such as chemical bonding and the formation of magnetism. The full paper on this research has been published (10 July) in the scientific journal, Nature.

As is well known, X-rays have the ability to pass through solid objects, but in the process the X-rays always experience some loss or absorption. This is why medical X-rays show features from inside a patient’s body – the X-rays experience increased absorption in more dense material such as bone and these areas show up as shadows on the X-ray image. The absorption of an X-ray occurs when the X-ray interacts and transfers its energy to an electron or an atom, so measuring the absorption of X-rays can tell us a lot about the state of these electrons and atoms. 

In 1941 a remarkable effect was observed by Gerhard Borrmann, known as the ‘Borrmann effect’. Borrmann noticed that X-rays passing through a crystal of germanium could experience much reduced absorption. This team of scientists realised that in the Borrmann effect it is only the dominant absorption, known as dipole absorption that is reduced. This allows a weak contribution to the absorption known as quadrupole absorption, to be measured. In most measurements, this smaller absorption is extremely difficult to distinguish from the stronger dipole absorption. Using X-rays at the STFC Daresbury Laboratory, they have been able to utilise this effect to measure the illusive quadrupole absorption component.

Determining quadrupole absorption is the answer to understanding many important material properties. Measurement of this absorption provides information about how the electrons are distributed in the area around atoms, known as orbitals, focusing on the orbitals which are responsible for magnetism and chemical bonding. Understanding these orbitals could be the key to understanding and developing new exotic magnets which can operate in extreme conditions and temperatures, such as those required to operate electric vehicles, advanced superconductors, or new X-ray imaging techniques.

Prof Steve Collins, Principal Beamline Scientist at Diamond, adds "Here at Diamond we will be able to build on the successes that the Daresbury Laboratory has facilitated in this area of research and advance these studies over the coming years."

-ends-

This research paper has been published as an advance online publication at http://www.nature.com/nnano/index.htm.

Quadrupole transitions revealed by Borrmann spectroscopy’ Robert F. Pettifer, Stephen P. Collins & David
Paper reference: doi: 10.1038/nature07099

Images are available upon request – please contact Wendy Taylor.

For further information contact:

Wendy Taylor MCIPR Press Officer
STFC Daresbury Laboratory
Daresbury Science & Innovation Campus
Daresbury
Warrington
Cheshire WA4 4AD
Tel. 01925 603232
Fax 01925 603195
Email: w.j.taylor@dl.ac.uk

Diamond Light Source Ltd contact details:

Isabelle Boscaro-Clarke, Head of Communications
Tel: +44 (0) 1235 778130
Mobile: +44 (0) 7990 797916
Email: isabelle.boscaro-clarke@diamond.ac.uk

University of Warwick contact details:

Peter Dunn Head of Press and Media Relations
Tel: 024 7652 3708
Mob: 07767 655860
Email: p.j.dunn@warwick.ac.uk

The Science and Technology Facilities Council ensures the UK retains its leading place on the world stage by delivering world-class science; accessing and hosting international facilities; developing innovative technologies; and increasing the socio-economic impact of its research through effective knowledge exchange partnerships.

The Council has a broad science portfolio including Astronomy, Particle Physics, Particle Astrophysics, Nuclear Physics, Space Science, Synchrotron Radiation, Neutron Sources and High Power Lasers. In addition the Council manages and operates three internationally renowned laboratories: 

• The Rutherford Appleton Laboratory, Oxfordshire
• The Daresbury Laboratory, Cheshire
• The UK Astronomy Technology Centre, Edinburgh

The Council gives researchers access to world-class facilities and funds the UK membership of international bodies such as the European Laboratory for Particle Physics (CERN), the Institute Laue Langevin (ILL), European Synchrotron Radiation Facility (ESRF), the European organisation for Astronomical Research in the Southern Hemisphere (ESO) and the European Space Agency (ESA). It also contributes money for the UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, and the MERLIN/VLBI National Facility, which includes the Lovell Telescope at Jodrell Bank Observatory.

The Council distributes public money from the Government to support scientific research. Between 2007 and 2008 we will invest approximately £678 million. 

Diamond Light Source

Diamond generates extremely intense pin-point beams of synchrotron light of exceptional quality ranging from x-rays, ultra-violet and infrared. For example Diamond’s x-rays are around 100 billion times brighter than a standard hospital X-ray machine or 10 billion times brighter than the sun.

Many of our everyday commodities that we take for granted, from food manufacturing to cosmetics, from revolutionary drugs to surgical tools, from computers to mobile phones, have all been developed or improved using synchrotron light.

Diamond will bring benefits to:

• Biology and medicine. For example, the fight against illnesses such as Parkinson's, Alzheimer's, osteoporosis and many cancers will benefit from the new research techniques available at Diamond.
• The physical and chemical sciences. For example, in the near future, engineers will be able to image their structure down to an atomic scale, helping them to understand the way impurities and defects behave and how they can be controlled.
• The Environmental and Earth sciences. For example, Diamond will help researchers to identify organisms that target specific types of contaminant in the environment which can potentially lead to identifying cheap and effective ways for cleaning polluted land.