[en] The feasibility of grazing angle sputtering for removal of a surface layer to improve depth resolution of high resolution Rutherford backscattering spectroscopy (HRBS) is examined. A Si(0 0 1) wafer with a SiO₂ layer of thickness 4.5 nm is irradiated by 0.5 keV Xe⁺ ions at a grazing angle of 15 deg. . The wafer is investigated in situ by HRBS. After removal of a part of SiO₂ layer by the grazing angle sputtering, the observed Si step at the SiO₂/Si interface in the HRBS spectrum becomes slightly sharper than the virgin sample, indicating that the grazing angle sputtering is useful for improvement of depth resolution in a deeper region

[en] A pseudo-Hermitian (PH) system made up of three coupled waveguides (trimer) with an overall balanced gain and loss is investigated in a parity time (PT)-symmetric-like regime. Remarkably, the pseudo hermiticity parameter controls the asymmetric spatial field modulation between left and right propagating waves whereby, a complex coupling arises that induces an additional source of non-Hermiticity, which in the system acts as a relative gain/loss Hellmann-Feynman correction. In this situation, we show that, transmissionless backscatterings are observed for the PH-trimer in the non PT broken phase. Interestingly, the scattering properties of PH-trimer result in multiple lasing states with different mechanisms. In particular, we show that in the PT-symmetric case, the lasing modes associated to the coherent perfect-absorption (CPA), occur from the spectral singularity induced by the Hermitian chain coupling and give rise to unidirectional invisibility in the direction of incident wave. On the contrary, additional emerging lasing modes in a PH regime result from the scattering maxima resonance. We demonstrate that this specific cases suppress the CPA-laser phenomenon and rather exhibit exceptional points characterized by reflectionless but also the points of transmissionless. Numerical beam propagations realized to emphasize the results are in good agreement with the scattering investigation until gain/loss parameter is around it’s value giving resonance. (paper)

[en] Material characterization by backscattering of ions in the energy range between a few keV and several hundred keV will be discussed. It will be shown that the descriptions used for ion surface scattering as well as Rutherford backscattering are applicable also at energies larger or lower respectively than those normally used for these techniques

[en] AlO_xN_y ultrathin films are used as insulating layers in advanced microelectronic devices. Structural characterization of these films is often done by the Rutherford backscattering (RBS) analysis. The RBS analysis of these oxinitrides is a difficult task since the relevant signals of the spectrum are washed out by the large substrate background and a considerable time is required for an analyst to characterize the sample. In this work we developed specialized artificial neural networks that are able to perform a fast and efficient analysis of the data. The results are in good agreement with traditional methods

[en] Atomistic simulation of ion channeling in Si shows that the lattice deformation around point defects, calculated by empirical potentials, gives a significant contribution to the backscattering yield of He ions channeled along major axial or planar directions. This effect, whose amount depends on defect type, beam-alignment condition and model potential used to relax the system, is expected to have consequences on the interpretation of Rutherford backscattering-channeling analysis. A model of structurally relaxed point defects, including split-<1 1 0> interstitials and vacancies, has been applied to the interpretation of multiaxial channeling analysis in the slightly damaged surface region of Si implanted with MeV ions. Despite the simple microscopic structure of damage assumed in the model, the method leads to a significantly better agreement with experiments then the standard models which treat defects as individually displaced atoms in an unperturbed lattice

[en] We consider the problem of recovering a smooth, compactly supported potential on R³ from its backscattering data. We show that if two such potentials have the same backscattering data and the difference of the two potentials has controlled angular derivatives, then the two potentials are identical. In particular, if two potentials differ by a finite linear combination of spherical harmonics with radial coefficients and have the same backscattering data then the two potentials are identical. (paper)

[en] The purpose of this research was to investigate the use of beta backscattering technique for determining elemental composition of binary alloys. A high energy beta source, Sr-90/Y-90, was selected to be used in this research so as to obtain high percentage of beta backscattered intensity and to minimize the uncertainty due to sample surface roughness. It was found that the sample thickness from about 250 mg/cm² would give the saturation backscattered intensity. The technique was tested with lead-tin alloy samples from factories and it was found that the beta backscattered intensity increased with increasing lead content in the sample. It was also found that the sensitivity can be improved significantly by placing an aluminum filter in front of the G M tube. Lead contents in 22 lead-tin alloy samples obtained from this technique were in good agreement with those obtained from the X RF, the atomic absorption and the specific gravity methods. The precision of this technique were found to be about ± 0.5% while the accuracy depended upon the standards used for calibration and the homogeneity of the samples

[en] Most RBS data analysis assumes straight trajectories and one single large angle backscattering event for the analysing beam, and flat sample surface and interfaces. Multiple scattering, plural scattering, and roughness are often ignored. This may lead to erroneous data analysis. In complex systems, understanding and taking into account these effects is essential. We discuss pitfalls that can occur when they are ignored, with emphasis on multilayer systems

[en] The review of using of compton backscattering method for determination of the beam energy in collider experiments is given

[en] The classification of surface flaw types was performed on the basis of angular dependence of backscattered ultrasound. The copper line adhered on the surface, cower line filled in groove, pure groove and the normal edge were adopted as various surface flaw patterns of glass specimen. A backward longitudinal profile was formed probably by the longitudinal wane scattering at and near 1st critical angle. The wave trains at the peak angles of the backward radiation profiles showed different shapes according to the superposition ratio of scattered and leaky waves. The asymmetry of the backward radiation profile arose due to the scattering effect of flaw. The additive resonance effect of copper line appeared in the left side of the profile. The peak angles of both the longitudinal and radiation profiles were shifted toward small angle by the scattering effect