Synthesis and characterization of lanthanum dicarbide-carbon targets for radioactive ion beams generation via the carbothermal reaction

In this study, we report the synthesis procedure for the attainment of thin pellets composed of lanthanum dicarbide (LaC2) grains and graphite, as a candidate material for the production of targets for the generation of radioactive ion beams (RIBs). The samples were obtained by thermal treatment of green pellets of lanthanum oxide or lanthanum oxalate (La2O3 and La2(C2O4)3, respectively) mixed with pure graphite, in a selected amount, at high temperature and in vacuum or inert gas flux. Several treatments, carried out at different temperatures and for different times, were applied and the obtained samples were characterized by scanning electron microscopy (SEM) equipped with the X-ray probe for elemental analysis (EDS) in order to investigate their surface morphology, sintering degree, grain size and chemical composition. X-ray diffraction (XRD) technique was adopted to unambiguously identify the final phases and their crystallographic features. XRD analyses allowed to study the carburization reaction extent and LaC2 crystals growth as a function of the treatment temperature. Moreover, the total porosity of the pellets was evaluated by measuring the bulk density after thermal treatment.