This title appears in the Scientific Report : 2014

##### Untersuchungen zur Produktion von $\beta^{+}$-aktiven Radionukliden des Scandiums und des Titans
Personal Name(s): Kuhn, Sebastian (Corresponding Author) Nuklearchemie; INM-5 2014 Jülich Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag 2014 163 p. Dissertation, Universität zu Köln, 2014 Report Book Dissertation / PhD Thesis Pathophysiological Mechanisms of Neurological and Psychiatric Diseases Neuroimaging Berichte des Forschungszentrums Jülich 4379 OpenAccess Publikationsportal JuSER
Please use the identifier: http://hdl.handle.net/2128/8100 in citations.
 Discrepancies in literature data regarding excitation functions and optimal energyranges for generation of the medically relevant radionuclides $^{43}$Sc, $^{44m+g}$Sc, $^{44}$Ti and${45}$Ti were solved by measurements of nuclear cross sections. The integral yields ofthe proton induced nuclear reactions on natural scandium in the energy range of 6 to30 MeV were examined to evaluate the feasibility of the production of $^{44}$Ti and $^{45}$Ti. Itwas found, that the ideal energy ranges are 12.5 to 5 MeV and 30 to 12 MeV for $^{45}$Tiand $^{44}$Ti, respectively. Up to 1.15 GBq/$\mu$Ah and 1.4 kBq/$\mu$Ah of $^{45}$Ti and $^{44}$Ti,respectively, could thus be produced. For the isolation of n.c.a. $^{45}$Ti in small volumesfrom bulk scandium a radiochemical method was developed utilizing the extractionchromatic resin 'DGA normal'. The separation was complemented by a first purification step using the the anion exchange resin 'DOWEX 1X8'. Considering a potential medical application the relevant nuclear decay data of the very attractive positron emitter $^{45}$Ti was investigated. By measuring thin, radionuclidicpure samples of n.c.a. material the absolute intensities of the four most important $\gamma$-rays were identified, and the positron emission probability was determined to be 85.7 ± 2.2%. In this context, first experiments were performed on the speciation of the $^{45}$Ti compound in aqueous media.Furthermore, with respect to the measurement of nuclear cross sections the analysisof the ratio of monitor nuclides enabled the improved experimental determination ofthe energy of projectiles in proton-, deuteron- and $\alpha$-induced nuclear reactions overan extended energy range. Thereby, the cross sections of the $^{nat}$Cu(p,x)$^{61}$Cu monitorreaction were ascertained and the scope of the $^{nat}$Ti(d,x)$^{48}$V monitor reaction wasenhanced by 25 MeV. In order to find an optimal way for the production of the potential PET-nuclides $^{43}$Sc and $^{44g}$Sc which is not based upon the irradiation of enriched target materials severalreaction pathways were examined. The reaction cross sections for the proton-, deuteron- and $\alpha$-induced reactions on natural calcium were quantified as well as the cross sections of the $^{nat}$K($\alpha$,x) nuclear reactions. Additionally, the alternative $^{44}$Ti/$^{44g}$Sc nuclide generator was discussed as a further way of production. $^{43}$Sc proved to be the most promising PET nuclide of scandium, whereby the $^{nat}$Ca($\alpha$,x)$^{43}$Sc nuclear reaction was identified to be its most effective production route which allows a yield of 128 MBq/$\mu$Ah with a negligible small amount of contamination.