X-ray technology can analyse surfaces with minimal damage

Newcastle University today launched the National X-ray Photoelectron Spectroscopy (XPS) Service, which will enable researchers to analyse the composition of the surface of a material and detect contamination or imperfection in the manufacturing process.

Standard technology only scans the first few nanometres of the surface but the new machine, first developed in Japan, enables scientists to remove the top atoms of a material to analyse the layers beneath without damaging them.

‘There’s a shift away from the standard applications in semiconductors and hard materials into softer materials and even biological functional coatings, tissue scaffolds and interfaces that are made to be tolerated by the body,’ Prof Peter Cumpson, the head of the new service, told The Engineer.

XPS works by bombarding a material with X-rays, which releases electrons from the top atomic layers of the material.

The amount of energy carried by each electron depends on what kind of atom it comes from so the energy spectrum reading can be used to determine the composition of the material.

Researchers can fire argon ions at the material to blast away the top layers of the surface but this tends to cause damage to the atoms beneath that they want to examine.

The technology uses clusters of several thousands of argon ions, which helps spread the impact and reduce the damage.

XPS has advantages over other analytic techniques in that the data it produces is relatively easy to interpret and samples require little preparation.

The facility could also benefit the development of technologies that require nanoscale engineering, such as thin-film solar cells, fuel cells, mobile phones and cell-specific drug delivery.

Cumpson said that the UK had a particularly strong surface-analytic community and although the centre would primarily provide an academic research base it would also be open to industry.

The EPSRC chose Newcastle to host the new facility, providing £3.15m over five years to establish and operate it alongside further investment from regional development agency One North East.