Spahn, Ingo (2006) Radiochemical Studies Related to the Development of New Production Routes of some Diagnostic and Therapeutic Radionuclides. PhD thesis, Universität zu Köln.
Nuclear reaction cross section measurements were done in connection with the development of new production routes of the therapeutic and diagnostic radionuclides P-32, As-71, As-72, As-73, As-74, Sr-82, Y-90, Sm-153 and Yb-169. Investigations on the production of n.c.a. Se-73 using novel targetry were also performed. Integral cross sections were measured for the S-nat(n,p)P-32, Zr-nat(n,p)Y-90 and Eu-nat(n,p)Sm-153 reactions using a 14 MeV d(Be) neutron field. The neutron spectrum was characterised using multiple foil activation and the code SULSA. Existing cross section data were validated within 10 - 15 %, thereby substantiating earlier evaluated and recommended excitation functions of the investigated reactions. It is inferred that for production of radionuclides via the (n,p) reaction, a fast neutron spectral source (e.g. spallation or fusion) would be better suited than a fission reactor. Proton and alpha particle induced reactions were investigated in the high-mass area for the production of Sm-153 and Yb-169 via alternative routes. Measurements were done for the first time on the Nd-nat(alpha,n)Sm-153 process over the energy range of 10 to 26.5 MeV and the possible production yield of Sm-153 amounts to 2 GBq. The excitation function of the Tm-169(p,n)Yb-169 reaction was determined over the energy range from threshold to 45 MeV and compared with the results of nuclear model calculation based on the ALICE-IPPE code. A good agreement was found. The calculated possible production yields are lower than those via the conventional (n,gamma) production route, but the produced Sm-153 and Yb-169 are in no-carrier-added form. Cross sections were also measured with regard to the production of As-71, As-72, As-73 and As-74 via the Ge-nat(p,xn) processes and the results were compared with those from the ALICE-IPPE calculations. Possible yields were calculated together with potential impurities. The various processes contributing to the formation of As-71 in the irradiation of Ge-nat were analysed by performing some additional measurements on enriched Ge-72. For the standardisation and validation of data for the production of Sr-82 via the Rb-nat(p,xn) process, cross section measurements on the formation of the long-lived impurity Sr-85 were done over the energy range of 25 to 45 MeV, a range where a gap still existed. Integral yields were calculated, allowing for an evaluation of the best production conditions of Sr-82. Preliminary studies on the production of n.c.a. Se-73 via the As-75(p,xn) reaction using AlAs as a novel target material were also carried out. Thick target yields were determined and first tests on the radiochemical separation of n.c.a. radioselenium from the target were performed.
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