Experimental measurement of threshold displacement energy in beryllium

Threshold displacement energy (E_d) is the most fundamental parameter defining and characterizing the irradiation damage of materials. However, there are no experimental values of the E_d available for beryllium. The beryllium’s E_d has been experimentally determined using conventional transmission electron microscopy. The orientation dependence for the onset of electron damage has been analyzed for beryllium when irradiated along 〈0001〉, <01$\overline{1}$0>, <1$\overline{2}1\overline{3}$> and <2$\overline{1}\overline{1}$0>. The values of E_d along these directions are found to be for beryllium, E_d<0001≥35.0 ± 0.8 eV, E_d<01$\overline{1}$0 ≥ 30.5 ± 0.7 eV, E_d<1$\overline{2}1\overline{3}$≥29.0 ± 0.7 eV and E_d<2$\overline{1}\overline{1}$0 ≥ 27.6 ± 0.8 eV. The orientation dependence of the displacement threshold energy of beryllium has also been discussed.