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  • Author: Stanislav Minárik x
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Kinetics of Electrons from Plasma Discharge in a Latent Track Region Induced by Swift Heavy ION Irradiation

Abstract

While passing swift heavy ion through a material structure, it produces a region of radiation affected material which is known as a "latent track". Scattering motions of electrons interacting with a swift heavy ion are dominant in the latent track region. These phenomena include the electron impurity and phonon scattering processes modified by the interaction with the ion projectile as well as the Coulomb scattering between two electrons.

In this paper, we provide detailed derivation of a 3D Boltzmann scattering equation for the description of the relative scattering motion of such electrons. Phase-space distribution function for this non-equilibrioum system of scattering electrons can be found by the solution of mentioned equation.

Open access
Quantization of Energy in 1D Model of Crystal Lattice with Local Perturbations Induced by Ion-Beam Impact

Abstract

In this paper, we propose theoretical basis for investigation of dynamics of acoustic phonons in a thin layers containing nano-scale structural inhomogeneities. One-dimensional (1D) model of a crystal lattice was considered to reveal specific features of the processes arising in such system of phonons in equilibrium state. Standard quantization of energy of 1D ionic chain vibrating by acoustic frequencies was carried out while the presence of foreign ions in this chain was taken into account. Since only two dimensions are dominant in thin layers, only longitudinal vibrations of the chain in the plane of the layer were considered. Results showed that foreign ions affect the energy quantization. Phonon-phonon interaction between two phonon`s modes can be expected if the mass of foreign ions implanted by ion-beam differs from the mass of ions in the initial layer.

We believe that the obtained results will help to understand the character of phonon systems in nanostructured thin layers prepared by ion-bem technology, and will allow better explain some thermal and electrical phenomena associated with lattice dynamics in such layers.

Open access
On the Relativistic Correction of Particles Trajectory in Tandem Type Electrostatic Accelerator

Abstract

A constant potential is applied to the acceleration of the ion-beam in the tandem type electrostatic accelerator. However, not just one voltage is applied, but instead a number of applications can be made in succession by means of the tandem arrangement of high voltage tubes. This number of voltage applications, which is the number of so-called "stages" of a tandem accelerator, may be two, three, or four, depending on the chosen design. Electrostatic field with approximately constant intensity acts on ions in any stage.

In general, non-relativistic dynamics is used for the description of the ion transport in tandem accelerator. Energies of accelerated ions are too low and relativistic effects cannot be commonly observed by standard experimental technique. Estimation of possible relativistic correction of ion trajectories is therefore only a matter of calculation. In this note, we briefly present such calculation. Our aim is to show how using the relativistic dynamics modifies the particles trajectory in tandem type accelerator and what parameters determine this modification.

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New Possibilities for Investigation of the Technological Texture Based on Measurement of Electric Parameters: Theoretical Analysis and Experimental Verification

Abstract

Texture is preferred orientation of crystallites in some polycrystalline materials. Different methods are applied to characterize the orientation patterns and determine the orientation distribution. Most of these methods rely on diffraction.

This paper introduces the principle of a method used for characterization of ceramics texture based on anisotropy of electrical properties of crystallites in ceramics. The mathematical framework of this method is presented in theoretical part of our work. In experimental section we demonstrate how the theoretical result could be used to evaluate technology texture of ceramic material intended for the production of electronic insulators.

Open access
On the Problem of the Ion Energy Loss in Thin Absorbers

Abstract

Exact determination of energy loss of ion in materials is still a non-trivial task because of relatively complicated changes of the ion`s stopping power S(E) during transport of the probing ion inside the material structure. Energy loss of ion in the material structure always depends on the current value of continually decreasing energy of the ion, indeed. A purely theoretical approach can be applied to the energy loss calculation in some typical cases. Average energy loss of ion can be determined by means of the Bethe-Bloch analytical theory (1-6) (in high velocity region) and the Lindhard-Scharff-Schiøtt (LSS) theory (7-10) (in low velocity region). Currently, there is no acceptable exact theory to determine the energy loss of ion in intermediate-velocity region (11) and experimental data must be used in that case. Basically, only a finite number of discrete experimental data is always available. Therefore, if the problem how much energy the projectile ion loses in a certain distance travelled is solved, the modelling of function S(E) based on some acceptable assumptions must be applied.

In this contribution, we present the energy loss calculations in intermediate-velocity region of ion based on linear interpolation of experimental data. Calculation was carried out for a kapton foil using the data taken from Ziegler, Biersack (12). Energy values of an ion along its trajectory inside the foil were found, and the mean projected range of ion penetrating into the foil was calculated. Finally, the energy resolution was evaluated taking into account straggling provided that the foil is used as an absorber in the ERDA experiment.

Open access
Charged Particle Dynamics Inside Electrostatic Quadrupole Deflection System with Circular Electrodes and Rotationally Symmetric Design

Abstract

This paper offers a theoretical study of special type of electrostatic quadrupole deflection system (EQDS) intended for ion beam optics. We deal with EQDS consisting of electrode pairs with rotational symmetry design. This systems was pre-designed for an ion beam modification and trajectory controlling. Basic assumptions for determination of transfer characteristics of such systems are analysed on the basic of charged particle dynamics.

We are especially interested in the electrostatic field distribution among electrodes inside the mentioned type of EQDS. Typical case of the Sturm-Liouville boundary value problem called Bessel`s differential equation arises in calculation of the electrostatic scalar potential with rotational symmetry. Bessel`s functions are particular solution of Laplace equation in this case. The scalar potential equations of motion for ions in this electrostatic field are found. The path of charge-particles in this field could be determined by solving the trajectory equation of motion in Cartesian coordinates.

Open access
Monte Carlo Simulation of the Electrical Conductivity of Rubber Compounds During Silanization

Monte Carlo Simulation of the Electrical Conductivity of Rubber Compounds During Silanization

Monte Carlo simulation of temperature dependence of electric conductivity of a model mixture system, which involves reaction with first order kinetics, was carried out on the basis of chemical kinetics laws. The temperature dependence of the conductivity of rubber compounds during the process of silane treatment was studied experimentally. Simulated temperature dependence of conductivity was compared with measured experimental results. The obtained experimental results and the data derived from numerical simulation are in satisfactory agreement. Effective method for monitoring and control of silane treatment of rubber compounds directly during the material preparation process can be proposed on the basis of the abovementioned finding.

Open access
Trace Elements Analysis by Pixe Spectroscopy

Abstract

The trace element analysis system is presented using Proton Induced X-ray Emission (PIXE) analysis at a new Ion Beam Centre in Trnava. Standard PIXE system dedicated to the measurement of thick solid samples was extended by a new application for trace element analysis in aerosol samples. The sample holder was modified with respect to the dimensions of the aerosol filters, and a new sample holder and a Faraday cup (FC) were made. The first results of the PIXE aerosol analysis are presented in this paper. Furthermore, the geometric efficiency of the detection system was verified using 55Fe radioactive source emitting monoenergetic Mn X-ray lines. The measured data were compared with the Monte Carlo simulations regarding/disregarding the X-ray attenuation.

Open access