Target nanomaterials at CERN-ISOLDE: synthesis and release data

Five different nanostructured target materials were tested and operated at ISOLDE in the year of 2014, three of them being carbon-based nanocomposites. In most cases such target materials have higher radioisotope intensities than standard targets and with apparently longer release characteristics. Here, an isotope release profile from a standard calcium oxide (CaO) powder target is compared to the nanostructured one. For all target materials, the synthesis is the key process since it determines the material characteristics and maximum operation temperature which, in turn, defines the final isotope yields (especially for exotic isotopes). An unexpected release of Ar isotopes from a nanometric CaO powder target, with its oven set to room temperature is described and a release mechanism is proposed: spallation recoil momentum from the nat Ca(p,x) 35 Ar reaction.