Anodically oxidised aluminium layer as a useful substrate for the fabrication of 147Pm sources for beta-ray thickness gauges

An anodically oxidised layer of aluminium was found to be a satisfactory substrate for holding millicurie amounts of carrier-free Pm-147 activity, which is used as a source of beta-radiation in beta-ray thickness gauges. The sources fabricated by this method showed satisfactory performance regarding leaching and adherence of the radioactivity held up in the oxide layer. Details regarding the anodic oxidation conditions used for making these source substrates are given. Leaching studies conducted on these sources indicated influence of the acid concentration at which Pm-147 activity was deposited in the oxide layer. Better performance characteristics of these sources could be achieved whenever Pm-147 activity was absorbed in the oxide layer under near neutral conditions of acidity.