Production of Co-55 via the Fe-54(d, n)-process and excitation functions of Fe-54(d, t)Fe-53 and Fe-54(d, alpha)Mn-52m reactions from threshold up to 13.8 MeV

摘要

For production of the medically interesting beta(+)-emitter Co-55 (T-1/2 = 17.6 h) via the Fe-54(d, n)-reaction, 91.6% enriched (Fe2O3)-Fe-54, mixed with Al powder, was pressed to a pellet which could be irradiated with 14 MeV deuterons at 4 muA in a water-cooled target system. A separation method was developed which led to > 99.9% pure Co-55 and allowed a recovery of the enriched target material. For a target thickness of E-d = 12.6 --> 5 MeV, the experimental thick target yield of Co-55 after chemical separation amounted to about 13 MBq/muA.h, which is about 60% of the theoretical value. In a 3 h irradiation at 4 muA, the batch yield of Co-55 achieved was 160 MBq (4.3 mCi). An 8 h irradiation could lead to a batch yield of about 400 MBq. The Fe-54(d, n) reaction leads to the highest purity Co-55 but it is essential that the isotopic enrichment of the target is not less than 90%. In addition to the production work, cross sections were measured for the Fe-54(d, t)Fe-53 and Fe-54(d, alpha)Mn-52m reactions using the standard stacked-foil technique and high-resolution gamma-ray spectrometry. The cross section ratio for the isomeric pair Mn-52mg is discussed in terms of the spins of the two states involved and the increasing projectile energy. [References: 17]