Damage morphology of Kr ion tracks in apatite: Dependence on dE/dx

With the aim of characterizing damage along nuclear tracks in apatite, Dura ngo fluoroapatite monocrystals were irradiated under a high fluence Kr-86 i on beam at the G.A.N.I.L. (Grand Accelerateur National d'Ions Lourds, Caen, France). The resulting irradiation damage was studied by associating CRBS spectrometry and chemical etching. By applying Poisson's law to the backsca ttering results, the nuclear track average effective radius R-e, was calcul ated for different steps along the ion path. On the other hand, the chemica l etching experiments allowed us to deduce three different damaging morphol ogies in correspondence to the R-e, values. For the first time in apatite, it has been shown that a defect fragmentation produced along the ion paths may be detected by chemical etching. These results were also applied to fis sion tracks in order to quantify the damage rate and to describe the damage morphology evolution along fission fragment paths.