The influence of the Coulomb explosion on the energy loss of H2 and H3 molecules channeling along the Si 〈100〉 direction

In this work we have measured the contribution of the Coulomb explosion to the electronic stopping power of molecular hydrogen ions (H+2 and H + 3 ) channeling along the Si 〈100〉 direction. To this end, we have used a SIMOX target, consisting of a crystalline 〈100〉 Si with a buried layer of SiO2. The measurements of the energy loss of H, H+2 and H + 3 have been carried out using the standard channeling Rutherford Backscattering Spectrometry. The energy loss have been measured around the Si 〈100〉 channel with the same energy per nucleon (150 keV / a.m.u.) as a function of the tilt and azimuthal angles. The present results show the effect of Coulomb explosion, which enlarges the protons traversal energy and consequently the channeling energy loss. This heating effect due to H+3 ions is about two times larger than H+2 molecules and amounts to about 5% of the total stopping power.