Fig. 1. Single crystal copper and polycrystalline copper substrates

Fig. 2. Dependence of the defect pairs number in single crystal copper on the number of helium atoms

Fig. 3. Defects evolution in single crystal copper with 150 helium atoms

Fig. 4. Dependence of the defect pairs number in polycrystalline copper on the number of helium atoms

Fig. 5. Effect of helium atoms on the tensile mechanical properties of copper

Fig. 6. Dislocation variation of single crystal copper during tensile property test（275 helium atoms）

Fig. 7. Dependence of the total dislocation length on the strain in copper at different helium atoms