Caracterización de centelleadores para reactores de fusión nuclear

Abstract

Nuclear fusion is considered nowadays as the most promising energy source in the long term. Magnetic confinement reactors, like the tokamak, are the most de veloped models, inside which plasma is confined. Diagnostics in these reactors are necessary to understand the plasma properties, and some of them use scintillators as active component. Therefore, they must be well characterized in order to choose the most suitable material for each diagnostic. In this context, a series of experiments were carried out in the CNA (Centro Nacional de Aceleradores), at Sevilla. They consisted in the irradiation of scintillators with energetic ions of 7Li and 51V, with energies from 1 to 3 MeV. The chosen scintillators were TG-Green, CSO, TCH, ZnS, YAG and YAGGd. Three aspects of the scintillators were characterized: linearity of emission rate with incident current; energy scan of light yield; and degradation. In the experiments, all the materials presented linearity between emission rate and incident current. On the energy scan, ZnS presented the highest light yield, followed by TG-Green, CSO, YAGGd, YAG and TCH. TCH was also the slowest degrading scintillator, while ZnS was the fastest one. The degradation results were fitted to Black Birk’s model, where a difference of two orders of magnitude was observed for the fluence of 50% (F1/2 ) between lithium and vanadium. The light yield results of the energy scan were also fitted to Birk’s model, where the experimental results with 7Li showed the predicted linearity with energy for the high stopping power limit. TCH stood out as a low degrading material with a high linear response, despite its low light yield. This recently developed material might be then considered for diagnostics like the Imaging Heavy Ion Beam Probe.