Experimental determination of track cross-section in Gd3Ga5O12 and comparison to the inelastic thermal spike model applied to several materials

Single crystals of gadolinium gallium garnet, Gd3Ga5O12 have been irradiated with various swift heavy ions (32S, 52Cr, 63Cu, 86Kr, 128Te, 129Xe, 181Ta, 208Pb, 238U) in the electronic stopping power regime. The extent of the induced damage is extracted from channelling Rutherford backscattering experiments and the corresponding track radii are deduced. At low beam energy (around 1.5 MeV/u), the electronic stopping power threshold of damage creation is 7.2 ± 1.2 keV/nm while it is 9.3 ± 0.9 keV/nm for beam energy around 6 MeV/u. The inelastic Thermal Spike model (i-TS) is used in order to calculate the track radii versus (dE/dx)e using λ, the mean diffusion length of the energy deposited on the electrons, as the only fitting parameter model. The i-TS model was extended to some other amorphizable materials like YBa2Cu3O7−δ, GeS and LiNbO3. The results, combined with previous ones extracted from BaFe12O19, Y3Fe5O12, Y3Al5O12 and α-SiO2 quartz data, showed that λ decreases when the band gap energy Eg increases. By extrapolation and depending of the material, the damage threshold induced by electronic excitation can appear at beam energy as low as 10−3 to 10−1 MeV/u.