Energy loss of α-particles channeled in metal-hydrogen systems

A simple method is discussed to calculate the energy loss of MeV α-particles channeled in a planar direction of a (transition) metal without and with a low concentration of hydrogen atoms. The contributicn of additional electrons of hydrogen atoms to stopping power is obtained by assuming that in the general case these can go to d-band and to conduction band. In particular for α-phase of Pd-H system all the additional electrons tend to fill the holes in the d-band. The contribution due to additional protons is obtained by considering proton-α-particle scattering and using the experimental activation energy for proton diffusion (0.23 eV for Pd-H) as the minimum energy that the protons could take in this scattering process. This latter contribution is found to be extremely small compared to the electronic part. (Auth.)