The role of micro-NRA and micro-PIXE in carbon mapping of organic tissues

This study reports the work developed in the Ion Implantation Laboratory (Porto Alegre, RS, Brazil) in order to implement the micro-NRA technique for the study of light elements in organic tissues. In particular, the work was focused on nuclear reactions employing protons and alphas with carbon. The (p,p) resonances at 0.475 and 1.734 were investigated. The (α,α) resonance at 4.265 MeV was studied as well. The results indicate that the yields for the 0.475 and 1.734 MeV resonances are similar. Elemental maps of different structures obtained with the micro-NRA technique using the 1.734 MeV resonance were compared with those obtained with micro-PIXE employing a SDD detector equipped with an ultra-thin window. The results show that the use of micro-NRA for carbon at 1.734 MeV resonance provides good results in some cases at the expense of longer beam times. On the other hand, micro-PIXE provides enhanced yields but is limited to surface analysis since soft X-rays are greatly attenuated by matter.