This study intends to investigate cascade damage structure produced by energetic ion irradiation. Cascade damage structure was preserved at low temperature below stage I where interstitial atoms begin to migrate. Then positron beam was implanted to the irradiated surface as a vacancy probe to evaluate vacancy concentration remained in the irradiated specimens. By this method, defect production efficiency was evaluated for iron irradiated with proton and carbon ions. The defect production efficiency values indicate enhanced recombination for carbon irradiation due to primary knock-on atoms with higher energies.

A Positron Beam Study on Vacancy Formation in Iron by Ion Beam Irradiation at Low Temperature. T.Iwai, K.Murakami, Y.Katano, T.Iwata, T.Onitsuka, H.Abe: Journal of Physics - Conference Series, 2010, 225[1], 012023