Porosity estimation of alumina samples based on resonant backscattering spectrometry

• Columnar porous alumina was investigated using the 16O(α,α)16O resonance scattering.
• The energy shift of the resonance peak in porous samples was recognized.
• The porosity of alumina samples was estimated based on resonance energy shift.

In this work, columnar porous alumina samples were investigated using the 16O(α,α)16O resonance scattering at 3.045 MeV. If the incident energy is slightly above the resonance energy, a resonance peak appears in the energy spectra of the backscattered ions. The position and width of this peak for non-porous samples are mainly determined by the experimental setup, whilst for porous materials, the peak position shifts towards higher energies under certain conditions. This effect can be explained by the lower amount of material which the ions encounter along the backscattered trajectories. The energy shift of the resonance peak towards higher energies was revealed experimentally and discussed theoretically. The estimated porosities of the samples based on this energy shift were compared with those evaluated from the graphical analysis of the images obtained by field emission scanning electron microscopy.