Amorphous tracks in insulators induced by monoatomic and cluster ions

Abstract

Amorphous tracks induced by monoatomic and cluster ion beams are compared in LiNbO 3 and Y 3 Fe 5 O 12 . In agreement with the prediction of our model, at high energy deposition R e 2 /S e ϭconst ͑R e is the effective track radius, S e is the electronic stopping power͒ for monoatomic and cluster ion irradiations. This indicates that the considerably higher energy density in the experiments with cluster ion beams does not modify the track formation. The analysis shows that the width of the thermal spike does not depend on the ion velocity in the range 0.02-20 MeV/nucleon. On the other hand, a strong variation of the efficiency of the energy deposition into the thermal spike g is observed around 2 and 4 MeV/nucleon for LiNbO 3 and Y 3 Fe 5 O 12 , respectively. The results cannot be explained by the variation of the ␦-electron distribution with the specific ion energy E. The importance of the electron-lattice ion and ion-ion interactions are emphasized. The relative shift of the g(E) curves is related to the different fraction of heavy elements in the two insulators. ͓S0163-1829͑99͒04129-6͔

Synthesis characterization and luminescence studies of gamma irradiated nanocrystalline yttrium oxide

“…In our previous work, we reported TL properties of swift heavy ion (SHI) irradiated combustion synthesized Y 2 O 3 . A prominent and well resolved TL glow with peak at 403 K is observed along with a weak TL glow with peak at 461 K in all SHI irradiated samples [45]. In the present work, gamma irradiated U:Y 2 O 3 and G:Y 2 O 3 shows similar results and this is due to the fact that SHI and γ-rays induce same kinds of defects responsible for TL.…”

Ion beam induced luminescence studies of sol gel derived Y2O3:Dy3+ nanophosphors

“…The decrease in IL intensity may be explained by track interaction model (TIM). According to this model, initially (0.375 Â 10 13 ions cm À 2 ) SHI ion fluence to create a cylindrical type tracks and such tracks are overlapping each other leadings to the formation of complex defects that reduce the luminescence intensity [37,38].…”

Kinetics of amorphization induced by swift heavy ions in α-quartz

“…Most theoretical analyses of the amorphization cross-section are based on the thermal spike approach [17,19]. However, the significant contribution of the halo in the near-threshold region strongly suggests that one should invoke cumulative models that are consistent with the dual core/ halo morphology of the tracks.…”

“…When the defect concentration reaches a certain threshold value the lattice collapses into an amorphous phase. Several specific models for defect creation have been proposed, including thermally-assisted bond breaking [19] and non-radiative exciton decay [20,21]. We consider that these models appear better suited to account for the structure and morphology of the damage tracks consisting of an amorphous core surrounded by a halo of point (and maybe extended) defects.…”