PRODUCTION AND RADIOCHEMICAL SEPARATION OF GD-147

The production of Gd-147 (T-1/2 = 38.1 h) via the Sm-147(He-3,3n)Gd-14 7 and Sm-144(alpha,n)Gd-147 processes was investigated. A target syste m was constructed which allowed irradiation of the target material Sm2 O3 with 15 mu A beams of 36 MeV He-3- or 27 MeV alpha-particles. A sep aration technique involving cementation with Na-amalgam followed by an ion exchange process was developed to separate the n.c.a. gadolinium from the bulk of Sm2O3 target material and from the n.c.a. europium is otopes. Experimental parameters such as sodium content in the amalgam, pH of the solution, Na+ concentration in the solution etc., were opti mised. The final purification of Gd-147 was done using a small glass c olumn (3 mm O x 120 mm) or an HPLC column (8 mm O x 300 mm) filled wit h a cation exchanger. Using 97% enriched Sm-147 and the separation tec hnique described here about 370-555 MBq (10-15 mCi) Gd-147 Of high rad ionuclidic 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 Sm-147(He-3,3n)Gd-147 process. The chemica l separation procedure developed also allowed an almost quantitative ( > 90%) recovery of the enriched target material for cyclic use. (C) 19 97 Elsevier Science Ltd.