Preparation of Alpha-spectrometric sources by coprecipitation with Fe(OH)3: Application to actinides

A method for the preparation of alpha-spectrometric sources of actinides by coprecipitation, using Fe(OH)3 as carrier, was investigated and applied to plutonium, americium and thorium. The pore size of the filters and the suitability of the addition of a substrate portion in order to saturate such pores was studied to provide optimal results. In the application to plutonium, americium and thorium, the influence of the amount of carrier and the addition of an activator (seeding) are discussed in detail for each element. In all cases, the procedure gives almost quantitative yields and spectra with a FWHM of about 40–60 keV when appropriate amounts of Fe(OH)3 are used. Because of its very low specific activity, the presence of 233Th in the sample was studied as a special case.