Atomic Displacement in Copper Irradiated with Protons, α-Particles and Carbon Ions from a Cyclotron

The irradiation of copper was performed at liquid helium temperature with charged particles, p, α, and carbon ions, from a cyclotron and the increase of electrical resistivity was measured. The ratio of the theoretical resistivity increase evaluated with the Kinchin-Pease model to the experimental one was 3.0 common to three particles, which was smaller by about 20% than that derived from an existing data on deuteron irradiation. The correction for ionization loss made that ratio decrease to 2.5 and the use of the Robinson-Torrens model which contains the direct recombination mechanism, made it decrease to 2. 0. This value is quite the same as that for neutron irradiation. The effect of direct recombination adopted in the Robinson-Torrens model is not so drastic in reducing the theoretical value.