Alpha Spectrometric Characterization Of Thin U-233 Sources For Th-229(M) Production

Four different techniques were applied for the production of U-233 alpha recoil ion sources, providing Th-229 ions. They were compared with respect to a minimum energy spread of the Th-229 recoil ions, using the emitted alpha particles as an indicator. The techniques of Molecular Plating, Drop-on-Demand inkjet printing, chelation from dilute nitric acid solution on chemically functionalized silicon surfaces, and self-adsorption on passivated titanium surfaces were used. All fabricated sources were characterized by using alpha spectrometry, radiographic imaging, and scanning electron microscopy. A direct validation for the estimated recoil ion rate was obtained by collecting Th-228 recoil ions from U-232 recoil ion sources prepared by self-adsorption and Molecular Plating. The chelation and the self-adsorption based approaches appear most promising for the preparation of recoil ion sources delivering monochromatic recoil ions.