Application of positron beam for the long range effect studies in proton implanted iron

The paper reports studies of pure, polycrystalline iron samples exposed to proton implantation with energies of 73 keV and 173 keV and doses of 3 x 10(15), 10(16) and 3 x 10(16) cm(-2). Additionally, two samples were exposed to multiple implantation with different energies and fluencies. Variable energy positron beam (VEP) was applied to the detection of irradiation-induced defects and their distribution. In turn, elastic recoil detection (ERD) method was used to estimate hydrogen concentration and its range. Analysis of VEP results was performed with VEPFIT code. The strong reduction of positron diffusion lengths in the implanted layers point out the presence of defects with high concentration. The thicknesses of these layers are in good agreement with hydrogen range evaluated by ERD. However, the presence of defects with lower concentration behind implanted zone was also detected when the free fitting was performed. The long range effect cannot be excluded.