Ligne de lumière microfocus et très haute dilution à l'ESRF pour les sciences de l'environnement

The EcoX Equipex is a consortium project managed by the Institute of Earth Sciences (ISTerre) from the University Grenoble Alpes to advance speciation studies of metal(loid)s in the chemical, life and environmental sciences using X?ray absorption spectroscopy (XAS) through the development of high luminosity analyser crystals at the European Synchrotron Radiation Facility (ESRF). Detection of X-ray fluorescence lines with analyser crystals has provided one of the cornerstones of modern XAS. However, all existing X-ray spectrometers used analyser crystals with a bending radius of R=1 m covering a solid angle lower than 0.1% of the whole emitted fluorescence signal. The instrumental shift at the heart of EcoX was the manufacturing of high luminosity analyser crystals with a bending radius of R=0.5 m to increase the detection efficiency (ideally by a factor 4) and realize the promise to reach, and even surpass, the mythic 1 ng/mg (ppm) detection limit heretofore impossible with R=1 m crystals, and establish XAS at ultra-high dilution.

The ESRF built a crystal analyser laboratory, which produces today state-of-the-art R=0.5 m Si crystals in a highly efficient and reproducible manner. A gain factor of 3.5 in luminosity has been achieved without loss of energy resolution and the results are published in the journal Review of Scientific Instruments.

At the same time, EcoX initiated the construction of three X-ray spectrometers.

1- The FAME-UHD beamline on the BM16 X-ray source (5-25 keV). FAME-UHD is a Collaborative Research Group (CRG) beamline integrated into the French CRGs programme jointly managed by the CNRS and CEA. This new synchrotron beamline hosts independent investigators since January 2017.

2- A mobile micro spectrometer (5-42 keV) housed on the existing BM23 beamline. It has been commissioned in June 2018.

3- A tender X-ray spectrometer (1.5 – 5 keV) on the existing ID26 beamline. It has been commissioned in April 2018.