Figure 4
(a) Photon spectra for different penetration depths (related to proton with different energies impinging with an incident angle of 30°) for a SiO2 sample and for a run using 106 particles (inset: detail of a photon histogramm for a 3 MeV proton incident at 30° on a SiO2 material sample); (b) total contribution to the kα photon emission as coming from all the penetration layers. For the calculation, only photons within the energy of 1.73–1.75 keV (i.e., very close to the kα) have been considered. This bin size is much smaller than what used in panel (a), where the bin size is 0.5 keV. The kα photon energy position is indicated with a dashed grey line.
