Purification of selenium from thorium, uranium, radium, actinium and potassium impurities for low background measurements

A technique of selenium purification from 232Th, 238U, 226,228Ra, 227Ac and 40K was developed. This technique is simple to perform and employs a minimum number of highly pure reagents (bidistilled water, nitric acid). Operations carried out during purification (elution, evaporation) practically exclude losses of the target product (chemical yields of Se > 99%). A test purification of 100 g of selenium was carried out using this technique. The efficiency of this technique was confirmed by low background gamma spectrometry of the purified selenium sample. Distribution coefficients of Th, U, Ra and Ac on DOWEX 50W- x 8 cation-exchange resin at different concentrations of selenium and nitric acid were experimentally determinated. Instrumental neutron activation analysis of bidistilled water, deionized water and nitric acid was performed. (orig.)