Comparison of energy distributions of positron- and electron-induced secondary electrons: Implications for slow positron emission mechanisms

Positron- and electron-induced secondary-electron-energy distributions have been measured from MgO(100) and Ni(110) crystals. The energy distributions for positron- and electron-induced secondary electrons from MgO and Ni and for the slow-positron emission from the MgO target have been fit by the same analytic function. This analytic function fails to fit the slow-positron energy emission spectrum from Ni. The similarity of positron-induced secondary electron and reemitted positron energy spectra suggests that the slow-positron emission process in ionic insulators may be analogous to secondary-electron generation