Absolute measurement of the elastic scattering cross section reaction on oxygen

Project: Research

Project Details

Description

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.
StatusFinished
Effective start/end date1/09/0431/12/06

Keywords

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