Speaker
Description
$\beta^+$ emitters are essential for positron based defect spectroscopy experiments that require compact setups. In this thesis, weak $^{22}$Na positron sources have been produced by irradiating aluminum targets with a 68 MeV proton beam. This approach avoids wet chemical processes, which are used in commercial production of carrier-free $^{22}$Na positron sources. The design of the target allowed the production of multiple positron sources at once as well as the analysis of the depth dependent activity of $^{22}$Na, which was found to be in agreement with the simulated depth profile. In total a $^{22}$Na activity of 140 $\pm$ 5 kBq was produced, which is spread over 50 individual aluminum discs. The strongest positron source has an activity of 4.62 $\pm$ 0.23 kBq. This activity makes up about half of the activity typically used in Positron Annihilation Spectroscopy and can therefore be used for such measurements. The production of stronger sources is desired for such experiments and can easily be achieved by irradiating the target for a longer period of time. Other radionuclides among $^7$Be, $^{48}$Sc, $^{54}$Mn and $^{56}$Co were produced with a total activity of 70 $\pm$ 5 kBq. If required, the production, aside from $^7$Be, can be prevented by using aluminum of a higher purity.
