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 q uartz 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 assumpt ion that the dechanneling of protons follows an exponential law are in good agreement with the measured spectra. yielding electronic stopping powers F or the specific crystal orientation that vary between 2.35 and 1.74 eV/A, r espectively. for the energy interval in consideration. The results are comp ared with the ones obtained in the past for simpler crystallographic struct ures, namely Si [100] and Si [111], and an attempt is made to explain the o ccurring similarities as well as the differences. (C) 2001 Elsevier Science B.V. All rights reserved.