These include X-ray absorption near edge structure (XANES) spectroscopy also known as “NEXAFS” or ‘near edge x-ray absorption fine structure” and Extended x-ray absorption fine structure (EXAFS). XANES and EXAFS are extremely powerful techniques finding a wide range of application spaces including chemistry, electronics, surface science, mineralogy, and biological sciences.

When exposed to x-rays, materials have a spectral region where absorption changes rapidly over a few eV, referred to as an edge (L or K). At energies just above the edge, there is a fingerprint of absorption (analysed in XANES) and at energies above that, there is the fine structure region (analysed in EXAFS). These fingerprints are unique to each chemical element allowing quantitative trace analysis.

Notably, proof of concept work for laser-driven XANES has been performed at the CLF. EPAC will be able to produce a high x-ray flux and at 10 Hz repetition rate, facilitating further development of laser-driven XAS. EPAC is capable of producing x-rays across a wide energy range allowing techniques using both hard and soft x-rays on the same beamline with only trivial changes in the laser target areas. Furthermore, the pulse duration of laser-driven x-rays is in the order of a few femtoseconds, thus allowing it to be synchronised to other laser pulses giving the capability for femtosecond scale pump-probe experiments.