Displacement mechanisms in electron-irradiated molybdenum

Electron irradiation of 99.95% VP-grade molybdenum and of 99.992% Marz-grade molybdenum in the energy range 0.8 to 1.7 MeV at 5 to 8°K yielded apparent threshold energies for the displacement of E = (810) keV and E = (850±40) keV, respectively. Best fitting with a theoretical displacement cross section was obtained using two-step displacement probability functions of the form P = 0 for T ≤ 33 eV, P = 0.18 for 33 ≦ T ≤ 42eV, P = 0.60 for T ≧ 42 eV and P = 0 for T ≤ 35 eV, P = 0.15 for 35 ≦ T ≤ 43 eV, PdMG = 0.85 for T ≧ 43 eV, respectively. The observed differences are explained by a 〈112〉 texture of the Marz-grade material.