Latent Tracks in Ion-Irradiated LiTaO3 Crystals: Damage Morphology Characterization and Thermal Spike Analysis

Systematic research on the response of crystal materials to the deposition of irradiation energy to electrons and atomic nuclei has attracted considerable attention since it is fundamental to understanding the behavior of various materials in natural and manmade radiation environments. This work examines and compares track formation in LiTaO3 induced by separate and combined effects of electronic excitation and nuclear collision. Under 0.71–6.17 MeV/u ion irradiation with electronic energy loss ranging from 6.0 to 13.8 keV/nm, the track damage morphologies evolve from discontinuous to continuous cylindrical zone. Based on the irradiation energy deposited via electronic energy loss, the subsequently induced energy exchange and temperature evolution processes in electron and lattice subsystems are calculated through the inelastic thermal spike model, demonstrating the formation of track damage and relevant thresholds of lattice energy and temperature. Combined with a disorder accumulation model, the damage accumulation in LiTaO3 produced by nuclear energy loss is also experimentally determined. The damage characterizations and inelastic thermal spike calculations further demonstrate that compared to damage-free LiTaO3, nuclear-collision-damaged LiTaO3 presents a more intense thermal spike response to electronic energy loss owing to the decrease in thermal conductivity and increase in electron–phonon coupling, which further enhance track damage.

“Thermal Spike” model applied to thin targets irradiated with swift heavy ion beams at few MeV/u

High electronic excitations in radiation of metallic targets with swift heavy ion beams at the coulomb barrier play a dominant role in the damaging processes of some metals. The inelastic thermal spike model was developed to describe tracks in materials and is applied in this paper to some systems beams/targets employed recently in some nuclear physics experiments. Taking into account the experimental conditions and the approved electron-phonon coupling factors, the results of the calculation enable to interpret the observation of the fast deformation of some targets.

Ultraviolet and Infrared luminescent Au-rich nanostructure growth in SiO2 by burrowing and inverse Oswald ripening process

We study the evolution of nanoparticle morphology through successive stages when Au-Si bilayer on SiO2 is irradiated with 500 keV Xe-ions and resulting luminescence in the UV, Visible and infrared range. An array of nanoscale island morphology is developed on the silica surface in the initial stage of evolution which undergoes gradual burrowing in the silica matrix accompanied by elongation of large ones in the direction of incident ions under cumulative ion irradiation. Burrowing is found to occur in order to minimize the surface free energy of the nanoparticles. Numerical simulation based on the unified thermal spike model shows formation of molten latent tracks due to ions energy release which drive the dewetting of the metal layer and further give mobility to nanoparticle atoms leading to burrowing in the later stage of evolution and elongation of large nanoparticles. Satellite nanoparticles are observed to grow around Au nanoparticles embedded in silica through nucleation of Au atoms dissolved in the matrix by incident ions. The varying diameters of the Au satellite nanoparticles seem to result in luminescence in the UV and infrared range. The observed structure may find application in surface enhanced Raman scattering, catalysis, and LEDs.

Assessing a thermal spike model of swift heavy ion–matter interactions via Pd1−xNix/Si interface mixing

A combination of density functional theory computations and swift heavy ion (SHI) mixing experiments is employed to assess the thermal spike model of SHI–matter interactions.

Modeling Thermal Effects in Metals Irradiated by Copper Nanoclusters

One of the promising areas in condensed matter physics is the study of the interaction of nanoclusters with various metallic targets. In this paper we investigate the thermal processes in metals irradiated with nanoclusters by the molecular dynamics method. In the framework of this method wave effects of the heat transfer are obtained, a feature which is absent in the thermal spike model. We repost results of computer simulation of the structural changes in irradiated copper targets of different sizes depending on the energy (in the range of 10–50 eV/atom) of copper nanoclusters.

Development of Continuum-Atomistic Approach for Modeling Metal Irradiation by Heavy Ions

Over the last several decades active research in the field of materials irradiation by high-energy heavy ions has been worked out. The experiments in this area are labor-consuming and expensive. Therefore the improvement of the existing mathematical models and the development of new ones based on the experimental data of interaction of high-energy heavy ions with materials are of interest. Presently, two approaches are used for studying these processes: a thermal spike model and molecular dynamics methods. The combination of these two approaches – the continuous-atomistic model – will give the opportunity to investigate more thoroughly the processes of irradiation of materials by high-energy heavy ions. To solve the equations of the continuous-atomistic model, a software package was developed and the block of molecular dynamics software was tested on the heterogeneous cluster HybriLIT.