Depth profiling of aluminium metal using slow positron beam
Slow positron beam Doppler-broadening technique was used to study depth profiling of aluminium metals sample. The variation of the line-shape parameters with incident positron energy was studied. Also, the depth profile of the S parameter was investigated. The positron implantation profile and backscattering fraction for aluminium sample was studied theoretically using data obtained empirically by Monte Carlo simulation. Results obtained revealed that aluminium metal has high S parameter in the surface and near surface regions and low S parameter in the bulk. The value of the S parameter decreased from the surface region reached a minimum at S = 0.292 and started to increase. While the W parameter increased and reached a value of 0.199 and started to decrease. The calculated positron implantation profile decreased with increase in the energy of the incident positrons but the implantation profile depth increased with an increase in the energy of the incident positrons. The results further revealed that the backscattering fraction increased with increase in the energy of the incident positrons.
Keywords: Material, positron annihilation, structure and vacancy
Nigerian Journal of Physics Vol. 18 (1) 2006: pp. 19-24