RESUMEN
The morphology and composition of uranium alpha sources with co-deposited platinum have been investigated by scanning electron microscopy (SEM) with energy dispersive X-ray fluorescence analysis (EDX), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) studies. Combined SEM and EDX measurements reveal the effect of porous platinum on the morphology of the sources which in turn affects their alpha-spectral resolution. The XPS analysis suggests that the presence of platinum initially increases the concentration of hydroxyl species in the deposits, which then act as centres for subsequent preferential uranium precipitation. XPS and XAFS analysis also provide for first time an indication of oxidation states of uranium present in the sources prepared by the Hallstadius method. These results are in line with Hansen's theory of electrodeposition of actinides.
RESUMEN
Glasses of general formula xSb(2)O(3) (1-x)B(2)O(3) (0 = x = 0.8) have been prepared by conventional melt- quenching. Mössbauer spectroscopy shows that a fraction of the Sb(3+) is converted to Sb(5+) and this fraction increases with x. High-field (11)B MAS NMR gives well-resolved resonances from boron atoms which are 3- and 4-coordinated to oxygen. The fraction of 4-coordinated boron, N(4), goes through a maximum value of 0.12+/-0.01 at x = 0.5. The position of the maximum in N(4) is consistent with the cation potential for Sb(3+), as observed for other systems. However, the low value of N(4) at this maximum is not so readily explained. The values are similar to those predicted if [BO(4)](-) were stabilised by [SbO(4)](+) but the trends with composition are different.