Determination of the stopping power of channeled protons in SiO₂ in the backscattering geometry

Energy spectra of protons channeling along the optical axis (c-axis) of a quartz crystal in the energy region E_p=1.7¯2.5 MeV in the backscattering geometry were taken and analyzed. Computer simulations based on the assumption that the dechanneling of protons follows an exponential law are in good agreement with the measured spectra, yielding electronic stopping powers for the specific crystal orientation that vary between 2.35 and 1.74 eV/Å, respectively, for the energy interval in consideration. The results are compared with the ones obtained in the past for simpler crystallographic structures, namely Si <1 0 0> and Si <1 1 1>, and an attempt is made to explain the occurring similarities as well as the differences.