Determination of alumina film thickness by alpha particle scattering

The scattering of accelerated alpha particles has been used to determine the surface oxide film thickness of anodized aluminium. The measurements were based on determining the difference between the energy of an alpha particle scattered from the surface oxide layer and that from the underlying metal. Films ranging in thickness from 10 to 130 microg/cm (2) were analysed non-destructively with a relative standard deviation of 3.5 %. The average time for an analysis was 30 min with an incident beam current of up to about 1 microA.