Production and radiochemical separation of 147Gd

The production of 147Gd (T1/2 = 38.1 h) via the 147Sm(3He,3n)147Gd and 144Sm(α,n)147Gd processes was investigated. A target system was constructed which allowed irradiation of the target material Sm2O3 with 15 μA beams of 36 MeV 3He- or 27 MeV α-particles. A separation technique involving cementation with Na-amalgam followed by an ion exchane process was developed to separate the n.c.a. gadolinium from the bulk of Sm2O3 target material and from the n.c.a. europium isotopes. Experimental parameters such as sodium content in the amalgam, pH of the solution, Na+ concentration in the solution etc., were optimised. The final purification of 147Gd was done using a small glass column (3 mm ø × 120 mm) or an HPLC column (8 mm ø × 300 mm) filled with a cation exchanger. Using 97% enriched 147Sm and the separation technique described here about 370–555 MBq (10–15 mCi)147Gd of high radionuclidic and chemical purity could be achieved. This corresponded to between 40 and 50% of the theoretical batch yield calculated from the excitation function of the 147Sm(3He,3n)147Gd process. The chemical separation procedure developed also allowed an almost quantitative (> 90%) recovery of the enriched target material for cyclic use.