New rock x-ray machines maintain world class service


A Geoscience Australia laboratory
technician loads samples into the new
x-ray fluorescence (XRF) spectrometer
instrument, which uses x-rays to
analyse the chemical components of
geological materials.

Two new state-of-the-art x-ray instruments will allow Geoscience Australia's laboratories to continue to deliver world class geochemical analysis of a wide range of geological and environmental samples.

The new x-ray fluorescence (XRF) spectrometer uses x-rays to analyse the chemical components of geological materials, including rocks and soil, as well as metals, hydrocarbons and organic matter such as plant leaves. The data obtained are essential to many of Geoscience Australia's projects and provide a fundamental understanding of the elemental components, or chemical building blocks, of geological samples.

An XRF spectrometer works by bombarding a sample with x-rays which results in energy of a characteristic wavelength being emitted, in essence a geochemical finger print.

"The new instruments incorporate many recent advances, including improved x-ray tubes and mechanical components that will help ensure Geoscience Australia retains its excellent reputation in the field of analytical geochemistry," the Deputy CEO of Geoscience Australia, Dr James Johnson, said.

"Our laboratory's participation in the international GeoPT Proficiency Testing Scheme, which calibrates Geoscience Australia's analytical procedures against geochemical laboratories from around the world, has shown that results achieved using the previous XRF instrument are equivalent to the best in the world. These results are expected to be further enhanced by the new machine," Dr Johnson said.

A new x-ray diffractometer (XRD) instrument will complement the results from the XRF spectrometer by focusing on the mineralogical composition of a sample. The XRD can identify specific crystalline minerals such as quartz, feldspar, mica and calcite. This extra information, combined with the chemical analysis provided by the XRF, provides vital information on the conditions under which rocks are formed.

All data obtained from the fully computer controlled machines are stored in a digital format for automatic transfer to Geoscience Australia's analytical databases, enabling these data to be directly accessible by the agency's researchers, and ultimately other clients through online databases and reports.

As well as work undertaken for Geoscience Australia's projects, XRF analyses also contribute to a range of collaborative projects with State and Territory government geological organisations, the CSIRO, Cooperative Research Centres and universities.