RBS Channeling MATLAB Application for Automated Measurement Control and Evaluation for 6MV Tandetron Accelerator

Rutherford backscattering spectrometry (RBS) in channeling regimes (RBS/C), as an ion beam analysis method performed on a Tandetron 6MV accelerator, generally gives precise information about the structure of crystalline samples by combining RBS signals in the random and aligned configurations. This paper presents details about the design and implementation of tailored RBS/C measurements (coarse and fine) and data evaluation application developed in MATLAB for in situ accelerator control system ARGUS, delivered by High Voltage Engineering Europa BV (HVEE). Additionally, we examined two different ways of stepping during the measurement to reduce the possible inaccuracies related with goniometer’s backslash affecting the evaluation of spectra. Verification experiment was carried out using a 2-MeV 4He+-beam directed on a Si (100) substrate. The channeling effect is seen as channeling dips of a lower signal in an otherwise rather homogeneous plane. Implemented application significantly facilitates the RBS/C measurement and analysis of the experiments, and also extends the ion beam analysis portfolio of Advanced Technologies Research Institute. Finally, software is ready-to-use for any Tandetron based ion beam facility with the ARGUS software for accelerator control.

Notes on reflection and refraction of evanescent plane waves on the boundary between gainy/lossy media

Reflection and transmission (refraction) of a homogeneous plane wave at the planar boundary of two dielectric media is a well known phenomenon commonly treated in nearly all standard textbooks. Here the analysis of reflection and refraction of evanescent plane waves on the planar boundary between various combinations of lossy, gainy and lossless media is performed. It is shown that by the appropriate choice of the profile of evanescence various effects can take place.

Principles of regular-shaped radome antennas study with a spherical scanner

The paper considers the characteristics determination method basing on amplifasometric measurements of near field of the «antenna-radio-transparent radome» system with use of a spherical scanner. The method is based on determination of components of the amplitude spectra of homogeneous plane waves through the amplitudes of vector spherical waves of the tested antenna and the «antenna-radio-transparent radome» system. It is assumed that the radome has a regular surface shape and is a single-layer radome. The proposed method, in addition to determination of radiation characteristics, allows for the given antenna field polarization to determine the complex coefficient of passage thorough the radome as a function of spatial frequencies. It is also shown that it is possible to estimate the complex dielectric permittivity of a single-layer radome, both by calculating the components of uniform plane waves, and directly from the reduced field components on the outer surface of radome. Ways to study the radiophysical characteristics of theradom, are proposed.

On the Stress State of a Heterogeneous Plate Made of a Material with a Step Change in Elastic Characteristics in the Presence of an Inclusion System and Temperature Influence

In the formulation of thermoelasticity and in the framework of the conventional theory of thermal stresses, the problem on the stress state of an elastic piecewise-homogeneous plane or an infinite plate at non-uniform steady-state heating is considered. On the interface of dissimilar materials, the compound plane is reinforced by a collinear system of absolutely rigid thin inclusions and is subjected to mechanical and thermal influences. First, to determine the temperature distribution in a piecewise-homogeneous plane the corresponding boundary value problem of the theory of steady-state heat conduction is solved using the integral Fourier transform. Solving this problem is reduced to solving a singular integral equation (SIE) that allows an exact solution. Further, the elastic displacements of points of the compound plane, caused by mechanical and temperature influence, are determined by the known methods of thermoselasticity. Based on these results, solving the problem of the contact interaction between the system of inclusions and a compound plane is again reduced to solving SIE, which also allows an exact solution. A special case is considered.

Plane Wave Reflection in a Compressible Half Space with Initial Stress

In this paper, the problem of wave propagation in a compressible half-space with an initial stress is considered. General discussion on the speed of wave in the presence of an initial stress is presented. Furthermore, reflection of a homogeneous plane P−wave is also studied. A special strain energy function dependent on this initial stress is used to understand the response of the materials. Explicit formulas for the reflection coefficients are also presented. General nonlinear theory and the theory of invariants are used to derive theoretical results. Graphical illustration of theoretical results for various numerical values of parameters show that initial stress has considerable bearing on the behavior of a plane wave.