Alpha spectrometric characterization of thin ${}^{233}$U sources for ${}^{229\text{(m)}}$Th production

Abstract

Four different techniques were applied for the production of ${}^{233}$U alpha recoil ion sources, providing ${}^{229}$Th ions. They were compared with respect to a minimum energy spread of the ${}^{229}$Th 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 ${}^{228}$Th recoil ions from ${}^{232}$U 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.

20 pages, 14 figures, 11 tables, ahead of print at Radiochim. Acta (2020)