The Laboratoire National Henri Becquerel (LNHB), located on the CEA Paris-Saclay site, is a division of the CEA LIST. It is one of the national metrology institutes federated by the Laboratoire National de métrologie et d’Essais (LNE) since 2005. In this capacity, the LNE delegates to the LNHB the role of the National Metrology Laboratory in the field of ionizing radiation.

The French Atomic Energy and Alternative Energies Commission (CEA) is a public research organization of a scientific, technical and industrial nature. A major player in research, development and innovation, the CEA is active in four areas: defense and security, low-carbon energy (nuclear and renewable), technological research for industry and fundamental research (material and life sciences). With its recognized expertise, the CEA is involved in setting up collaborative projects with numerous academic and industrial partners.

The experimental chamber, CASTOR, is used to analyze thin layers in the nanometer range, using monochromatic X-rays provided at the Metrology beamline of SOLEIL synchrotron facility.
The experimental approach combining X-ray reflectivity (XRR) and grazing Incidence X-Ray Fluorescence (GIXRF) provide compositional and structural information on the analyzed samples.

The goniometer CASTOR can be installed on both branches of the Metrology beamline at the SOLEIL synchrotron facility. It is equipped with calibrated photodiodes and spectrometer in order to perform a combined analysis of the x-ray reflectivity and the fluorescence in grazing incidence mode on thin-film samples. The analysis can be performed in reference-free mode, deducing the sample thin-film structure from the atomic fundamental parameters by mathematical modelling and with an optimization procedure.