scholarly journals Reflection of keV light ions from solids at oblique and grazing incidence

2009 ◽  
Vol 24 (3) ◽  
pp. 188-194 ◽  
Author(s):  
Jovan Vukanic ◽  
Rodoljub Simovic
Keyword(s):  
Reflection Coefficient ◽  
Multiple Scattering ◽  
Cross Section ◽  
Scattering Theory ◽  
Grazing Incidence ◽  
Universal Functions ◽  
Light Ions ◽  
Analytical Formulae ◽  
Analytical Approaches ◽  
Good Agreement

The particle reflection coefficient of light keV ions backscattered from heavy targets has been determined by two different analytical approaches: by the single collision model in the case of nearly perpendicular incidence and by the small-angle multiple scattering theory in the case of glancing angles of incidence. The obtained analytical formulae are approximately universal functions of the scaled transport cross-section describing the reflection of all light ions from heavy targets. Going from perpendicular to grazing incidence, the transition from pure single to pure multiple scattering type of reflection is observed. For larger values of the scaling parameter the results of these theories cover the whole region of ion incident angles and the present estimates of the particle reflection coefficient are in good agreement with the results obtained from the empirical formula of Tabata et al.

X -Ray Absorption Near Edge Structure (XANES) Calculations for the Amorphous Fe80B20- and Ni80B20-Alloys

1989 ◽  
Vol 44 (3) ◽  
pp. 189-194
Author(s):  
P. Kizler ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Multiple Scattering ◽  
Scattering Theory ◽  
Edge Structure ◽  
Multiple Scattering Theory ◽  
X Ray ◽  
Bond Angles ◽  
Complex Features ◽  
X Ray Absorption ◽  
Good Agreement

Xanes spectra of the amorphous Fe80B20- and Ni80B20-alloys have been investigated using the electron multiple scattering theory of Durham et al. The calculations were based on several models for the structure of amorphous Fe80B20 and Ni80B20. Very good agreement between theoretical and experimental XANES curves was met. Opposite to former expectations for obtaining information on bond angles by XANES, this study shows that XANES points to more complex features of the structure than can be expressed in terms of bond angles.

Multiple Scattering Calculations Applied to XAS: A Structure and Electronic Sensitive Tool

1991 ◽  
Vol 253 ◽  
Author(s):  
Philippe Sainctavit ◽  
J. Petiau
Keyword(s):  
Multiple Scattering ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Scattering Theory ◽  
Spectral Features ◽  
Absorption Cross ◽  
Multiple Scattering Theory ◽  
X Ray ◽  
Sensitive Tool ◽  
X Ray Absorption

ABSTRACTWe present an application of multiple scattering theory with “muffin-tin” potentials to the calculation of X-ray absorption cross section. We have measured and calculated the K-edge spectra of atoms in compounds with zincblende structure : SiC, ZnS. We show that some spectral features can be precisely related to the local environnement around the absorbing atom.

ELASTIC pd SCATTERING AT HIGH ENERGIES

1988 ◽  
Vol 03 (05) ◽  
pp. 1301-1319 ◽  
Author(s):  
V.M. BRAUN ◽  
L.G. DAKHNO ◽  
V.A. NIKONOV
Keyword(s):  
Experimental Data ◽  
Differential Cross Section ◽  
Multiple Scattering ◽  
Cross Section ◽  
Differential Cross ◽  
Scattering Theory ◽  
High Energy ◽  
Multiple Scattering Theory ◽  
High Energies

High energy differential pd cross section is calculated in the framework of the multiple scattering theory, inelastic correction included. Special attention is paid to the analysis of the calculation uncertainties. The results agree well with the experimental data obtained at ISR energies in the q2 range 0.06–1.05 (GeV/c) 2. The calculation accuracy is proved to be not worse than 10–20% at q2~0.2 (GeV/c) 2 and much better at small q2, namely, ~1% in the optical point. Prediction for the differential cross section at UNK energy E lab =3 TeV is given.

MULTIPLE SCATTERING CALCULATIONS OF GBMEED

1997 ◽  
Vol 04 (05) ◽  
pp. 959-963
Author(s):  
U. KORTE
Keyword(s):  
Multiple Scattering ◽  
Scattering Theory ◽  
Diffuse Scattering ◽  
Grazing Incidence ◽  
Medium Energy ◽  
Surface Layers ◽  
Thermal Diffuse Scattering ◽  
Focusing Effect ◽  
Diffraction Effects ◽  
Thermal Diffuse

A method for computing grazing-incidence backscattering medium energy (1–3 keV) electron diffraction (GBMEED) is presented. The technique was recently proposed as a structural tool exhibiting diffraction effects resembling those of XPD. In GBMEED the intensity of quasielastically thermal diffuse scattering is measured at large scattering angles such that different atoms can be assumed to vibrate independently, and thus represent localized sources for diffuse scattering in the surface layers. The basis of the calculations is the multiple scattering theory of diffuse RHEED adopted to the medium energy case with a vibrating atom as source of diffuse scattering. Calculated plots of the intensity versus azimuthal/polar exit angle for an In overlayer on Si(111) show the forward focusing effect along the source-scatterer direction (well known from XPD) and further fine structure.

scholarly journals Experimental Analysis of Ultrasonic Multiple Scattering Attenuation through the Air with Fine Dust

2021 ◽  
Vol 11 (2) ◽  
pp. 694
Author(s):  
Ukyong Woo ◽  
Hajin Choi ◽  
Homin Song
Keyword(s):  
Signal Processing ◽  
Multiple Scattering ◽  
Cross Section ◽  
Approximation Theory ◽  
Experimental Analysis ◽  
Scattering Theory ◽  
Ultrasonic Attenuation ◽  
Fine Dust ◽  
Ultrasonic Scattering ◽  
Scattering Attenuation

In this study, we experimentally evaluated the application of multiple scattering theory for measuring ultrasonic attenuation. Based on the independent approximation theory, the method adopted for calculating the attenuation of coherent waves through air with fine dust is discussed. To obtain a scattering wavefield, a unique ultrasonic scattering hardware was developed, and signal processing schemes were suggested. Four cases of standard particle doses (0, 0.004, 0.008, and 0.012 g) were investigated inside a chamber. The results obtained from the experiments demonstrate that the proposed signal processing approach successfully calculates the scattering attenuation, which correlates well with the applied doses of fine dust. In addition, we discuss the irregular shape and composition of fine dust relative to the scattering cross-section.

Effect of leakage and blockage on the acoustic behavior of particle filters

2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee
Keyword(s):  
Transfer Matrix ◽  
Particle Filters ◽  
Acoustic Analysis ◽  
Transmission Loss ◽  
One Dimensional ◽  
Filter System ◽  
The Difference ◽  
The One ◽  
Analytical Approaches ◽  
Good Agreement

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.

scholarly journals Experimental demonstration of negative refraction with 3D locally resonant acoustic metafluids

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benoit Tallon ◽  
Artem Kovalenko ◽  
Olivier Poncelet ◽  
Christophe Aristégui ◽  
Olivier Mondain-Monval ◽  
...  
Keyword(s):  
Experimental Data ◽  
Yield Stress ◽  
Multiple Scattering ◽  
Silicone Rubber ◽  
Acoustic Waves ◽  
Scattering Theory ◽  
Negative Refraction ◽  
Volume Fraction ◽  
Experimental Demonstration ◽  
Acoustic Beam

AbstractNegative refraction of acoustic waves is demonstrated through underwater experiments conducted at ultrasonic frequencies on a 3D locally resonant acoustic metafluid made of soft porous silicone-rubber micro-beads suspended in a yield-stress fluid. By measuring the refracted angle of the acoustic beam transmitted through this metafluid shaped as a prism, we determine the acoustic index to water according to Snell’s law. These experimental data are then compared with an excellent agreement to calculations performed in the framework of Multiple Scattering Theory showing that the emergence of negative refraction depends on the volume fraction $$\Phi$$ Φ of the resonant micro-beads. For diluted metafluid ($$\Phi =3\%$$ Φ = 3 % ), only positive refraction occurs whereas negative refraction is demonstrated over a broad frequency band with concentrated metafluid ($$\Phi =17\%$$ Φ = 17 % ).

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