Preparation of57Co standard solution and its activity measurement

⁵⁷Co was produced with high pure nature iron irradiated by 8.5MeV deuterons. TBP-benzene extraction method and anion-exchange method were used to separate and purify it. The purified⁵⁷Co was prepared into standard solution of about 30 to 50 g Co²⁺/ml carrier concentration and about 0.1 mol/l HCl. The specific activity of the standard solution was measured with 4 (ppc)- coincidence counting method. The final result was 476.82(1±0.42%)Bq/mg.