Absolute measurement of the elastic scattering cross section reaction on oxygen

Project: Research

Project Details


Resonant scattering cross sections are currently used for light elements backscattering spectroscopy. Many studies of the 16O(alpha,alpha)16O reaction cross section, particularly focused on the peak at ER=3.045 MeV, have been made: results are in disagreement. The very high stability of energy of the Tandetron accelerator ALTAÏS from the LARN laboratory allows a reliable measurement of this cross section.

Thin tantalum coatings have been deposited by magnetron sputtering on a light carbon substrate, in order to isolate the oxygen signal from any background signal. These layers have been anodically oxidized under constant current conditions. Two Ta2O5 standards were produced: a thin oxide layer (~4 keV energy loss) for resonances probing, and a thicker layer (~12keV energy loss) to scan the regions where the cross section shows slow variations.

Cross section was measured for energies between 2.4 and 6.0 MeV, at typical backscattering angles 165° and 170°. The main resonance was fixed at ER=3031.7 keV. Deviations from previous measurements have been observed at high energies.

In order to check the performance of the 16O(alpha,alpha)16O reaction for oxygen analysis, multilayers TTiO2/Si, TiN/Si, TiO2/TiN/Si, TiN/TiO2/Si, TiO2/C samples, and a sample of vaporised functionalized nanotubes were characterised. Advantages of the technique in case of low oxygen concentrations have been pointed out.
Effective start/end date1/09/0431/12/06


  • accelerator
  • oxygen
  • elastic scattering
  • differential cross-section