X-ray techniques

What are X-ray diffraction (XRD) and X-ray fluorescence (XRF)?

These two methods and therefore measuring devices use X-rays to analyse solid samples (or even liquid samples for XRF). They enable us to study a rock or sediment, from its chemical composition with XRF, to its mineralogy with XRD.

How do these tools work?

X-rays are a form of electromagnetic radiation (like light) but invisible to the eye and with a wavelength between 0.01 and 10 nanometres. These rays are commonly used in medicine for X-rays. In both cases, the sample is bombarded with X-rays.

• In XRF, the energy of the X-rays is sufficient to cause the atoms to react and emit secondary radiation, characteristic of the elements present in the sample.
• A mineral sample is composed of molecules that stack up in a particular way, forming crystals. In XRD, the radiation is said to be diffracted, i.e. it is deflected at a particular angle characteristic of the crystals present in the sample. This allows us to determine the minerals that make up our sample (quartz, pyrite, etc.).

What is studied with these tools?

These techniques are used to carry out studies on various so-called solid samples (sediments, basalts, sulphides, nodules, etc.) and to better understand their formation in the natural environment