Stored Energy, Volume, and Resistivity Change in Neutron Irradiated Aluminium

Pure aluminium samples are irradiated at 4 °K in the core of the Munich Research Reactor. Measurements are then made of the release of the stored energy (Δ Q and the changes in the length (Δ l ) and electrical resistivity (Δ∂) during annealing between 4 and 300 °K. For the first annealing stage, observed between 4 and 55 °K, these measurements yield {article}{empty}{document}Δ QΔ = 38.3 ± 1.3Ws/gμ Ω cm,Δ l/lΔ = 0.12 ± 0.005%μ Ω cm {document} . The corresponding ratios for the two other observed stages have similar values. The experimental results suggest the following values for specific properties of defects in aluminium ( E F , E i , E v being the energies of a Frenkel defect, an interstitial, and a vacancy, respectively; V F is the volume change per Frenkel defect; ∂ F , ∂ i , ∂ v are the resistivity changes per unit concentration of Frenkel defects, interstitials, and vacancies, respectively): E F = 3.4 eV; E v = 0.8 eV; E i = 2.6 eV; V F = 1.2 atomvol.; ∂ F = 340 μΩcm; ∂ v = 220 μΩcm; ∂ i = 120 μΩcm.