Residual rate of defects in heavy-ion induced cascades

Nickel single crystal specimens were bombarded with various heavy ions, 0.2 MeV He+, 2.0 MeV C+, 3.5 MeV Si2+, 4.0 MeV Ni2+ ions, up to the same amounts of displacement per atom (dpa), and residual rate of defects in heavy-ion induced cascades was investigated by Rutherford backscattering (RBS) spectroscopy using channeling technique. Displacement damages are found to be variable with primary knock-on atom (PKA) energies, revealing a cascade quenching due to the recombination of point defects produced primarily. Residual rate of defects obtained experimentally are qualitatively in agreement with existing theoretical calculations.