Papers by Keyword: Stopping Power

Abstract: Nuclear dispersion is an important aspect in the process of slowing down ions by transferring their momentum to the target atoms and in determining path of the ion. This paper concerns the quantitative evaluation of the mechanism at which helium ions lose their energy when penetrate into a solid and the eventual distribution of the helium ion while stopping inside the Gallium Arsenide compound (GaAs). The first order effects of the atoms of the compound such as the electronic excitation of the atom, the lattice damage incurred to it, as well as the production of phonons in Gallium Arsenide due to the helium ions are also taken into account. The main finding is the mechanism of penetration of helium ions in GaAs, which is affected by the energy, the angle of incidence, and penetration density of the helium ions. It is found out that the energy has major impact than the angle of incidence in the interaction.

Abstract: The energy loss for swift heavy ions, covering Z=3-29(~0.2 - 5.0MeV/n), has been calculated in the elemental absorbers like C, Al and Ti. The present calculations are based on Bohr’s approach applicable in both classical and quantum mechanical regimes. The major input parameter, the effective charge, has been calculated in a different way without any empirical/semi-empirical parameterization. The calculated energy loss values have been compared with the available experimental data which results in a close agreement.

Abstract: Slowing down processes for a proton and a carbon ion penetration through plasmas are studied within the dielectric response theory.The results show that the stopping power of ion will increase in lower projectile velocity, while the value of stopping power will decrease for higer velocity, and there is a maximum value for stopping power for some projectile velocity due to the resonace of excitation of plasmas. In addition, the stopping power will have higher value for carbon ion than proton due to the effects of charge states. Introduction

Abstract: The channel effects of carbon nanotubes is studied by a fast proton in the framework of linearized hydrodynamic theory. General expressions of induced potential, the self-energy, and the stopping power are obtained for such a charged particle moving paraxially in a carbon nanotube. The influences of the damping factor and the carbon nanotube radius on the stopping power and self-energy are discussed. The results show that the velocity dependences of these quantities are strongly affected by the damping factor and the nanotube radius, the relevant results will be helpful for study of the transport of charged particles through nanotubes.

Abstract: Stopping power of test ions in magnetized plasmas is investigated by means of linearized Vlasov Poisson theory. The influences of the magnetized field, the angle between the test particle velocity and magnetized field, and certain plasma densities and temperatures on the stopping power are studied. Simulation results show that the stopping power emerges a peak around the plasma thermal velocity due to the electron excitation. When the magnetized field is strong, the stopping power is strengthened; while when the magnetized field is weak, the stopping power is weakened.

Abstract: t is well established that the properties of the materials can be tailored as per specific requirements as a result of swift heavy ion irradiation. This is because of the radiation damage induced changes in the properties of the materials as a result of the energy loss process of the incident ions along their trajectory. In order to correlate such induced changes with the energy loss of the impinging ions, the exact evaluation of energy loss for swift ions in different materials is extremely important. Keeping in mind the polymers as versatile materials, in the present work, we have focused on energy loss calculations for swift heavy ions with Z= 3-29 in different polymeric absorbers, e.g. Polypropylene PP (C₃H₆), Polycarbonate PC (C₁₆H₁₄O₃), Polyethylene terepthalate PET (C₁₀H₈O₄), Polyethylene naphthalate PEN (C₇H₅O₂), Diethylene glycol bis (allyl carbonate) CR-39 (C₁₂H₁₈O₇), Cellulose nitrate LR-115 (C₆H₉O₉N₂) and Polypyromellitimide KAPTON (C₂₂H₁₀O₅N₂) in the energy range 0.5-6.00 MeV/n. The present calculations have been made by employing the proper energy loss formulation applicable both at low as well as high energies, involving a new approach for effective charge parameterization without any empirical/semi-empirical means. A close agreement between these calculated and experimentally measured values has been observed. Such calculations will provide an input towards the modeling or simulation for swift heavy ion induced changes in the properties of materials.