scholarly journals Energy Dependence of Total Cross Section for Scattering of Helium Atoms from Isolated Atomic Steps

1970 ◽  
Vol 34 (1) ◽  
pp. 23-31
Author(s):  
Kazi Shamim Sultana ◽  
MZ Hafiz
Keyword(s):  
Total Cross Section ◽  
Energy Dependence ◽  
Cross Section ◽  
Cross Sections ◽  
Helium Atoms ◽  
Surface Steps ◽  
Realistic Interaction ◽  
Academy Of Sciences ◽  
Scattering Cross Sections ◽  
Realistic Potentials

The scattering of helium atoms from growing metal. surfaces is dominated by the interactionbetween incident atoms and isolated surface steps. Understanding the process has been constrainedby the lack of both a realistic interaction potential and a satisfactory method for treating thescattering from a defect, which, because of the height difference of the adjoining terraces, extendsto infinity. We have calculated step scattering cross sections for Cu(001) surface. The calculationsmake use of realistic potentials that reproduce the scattering from low index planes and are createdfrom non-spherical, pairwise repulsive and attractive terms. The step scattering is isolated from thatof adjoining terraces using the linearity of summation of scattering amplitudes in the singlescattering regime. The results for equivalent step and terrace-site potentials give a total crosssection significantly less than the experimental value. The total cross section increases with heliumbeam energy, contrary to the expectations that it is dominated by scattering from the attractive partof the potential. The present work confirms the prediction of our previous study that not the Vander Waals interaction but the hard wall of the scattering potential dominates the step scattering.Key words: Energy dependence; Scattering; Helium atoms; Atomic stepsDOI: 10.3329/jbas.v34i1.5489Journal of Bangladesh Academy of Sciences, Vol.34, No.1, 23-31, 2010

Measurement of the total cross section of titanium with neutrons of 6–8 m/s

1982 ◽  
Vol 60 (5) ◽  
pp. 632-635 ◽  
Author(s):  
P. Gabriel ◽  
J. M. Robson
Keyword(s):  
Total Cross Section ◽  
Inelastic Scattering ◽  
Thermal Neutron ◽  
Cross Section ◽  
Cross Sections ◽  
Scattering Cross ◽  
Scattering Cross Sections ◽  
Inverse Velocity

The sum of the absorption, incoherent, and thermal inelastic scattering cross sections of natural titanium has been measured at 293 K for three neutron velocities in the range 6–8 m/s. They agree with values to be expected on the basis of an inverse velocity extrapolation from measurements near thermal neutron velocities.

Absolute inner-shell cross section determination for EELS analysis

1988 ◽  
Vol 46 ◽  
pp. 534-535
Author(s):  
P.A. Crozier
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absolute Cross Section ◽  
Specimen Thickness ◽  
Mass Thickness ◽  
Scattering Cross ◽  
Before And After ◽  
Estimated Error ◽  
Scattering Cross Sections ◽  
Electron Microscopist

Absolute inelastic scattering cross sections or mean free paths are often used in EELS analysis for determining elemental concentrations and specimen thickness. In most instances, theoretical values must be used because there have been few attempts to determine experimental scattering cross sections from solids under the conditions of interest to electron microscopist. In addition to providing data for spectral quantitation, absolute cross section measurements yields useful information on many of the approximations which are frequently involved in EELS analysis procedures. In this paper, experimental cross sections are presented for some inner-shell edges of Al, Cu, Ag and Au.Uniform thin films of the previously mentioned materials were prepared by vacuum evaporation onto microscope cover slips. The cover slips were weighed before and after evaporation to determine the mass thickness of the films. The estimated error in this method of determining mass thickness was ±7 x 107g/cm2. The films were floated off in water and mounted on Cu grids.

DOUBLE PION PHOTOPRODUCTION EXPERIMENT AT LNS–TOHOKU

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2313-2316 ◽  
Author(s):  
◽  
H. KANDA ◽  
N. CHIGA ◽  
Y. FUJII ◽  
K. FUTATSUKAWA ◽  
...  
Keyword(s):  
Total Cross Section ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Pion Photoproduction ◽  
Total Cross Sections ◽  
Free Proton ◽  
Double Pion ◽  
The Cross

The total cross sections for the π+π− photoproduction on the deuteron were measured in an energy range of 0.8 to 1.1 GeV. The obtained total cross section for the quasi-free π+π− photoproduction on the deuteron was about 60 % of those on the free proton. The cross section for Δ++Δ− photoproduction was derived from the non-quasi-free π+π− photoproduction events. It was smaller than the previous data.

scholarly journals ENERGY LOSS IN CONDENSED MATTER OF H1 AND He4 IN THE ENERGY RANGE 4 < E < 30 kev

1962 ◽  
Vol 40 (12) ◽  
pp. 1749-1764 ◽  
Author(s):  
Arie Van Wijngaarden ◽  
Henry E. Duckworth
Keyword(s):  
Thin Films ◽  
Aluminum Oxide ◽  
Energy Loss ◽  
Energy Range ◽  
Energy Dependence ◽  
Cross Section ◽  
Cross Sections ◽  
Condensed Matter ◽  
Forward Direction ◽  
Electronic Component

Measurements are reported of the energy loss suffered by H1 and He4 particles, of 4- to 30-kev energy, in passing through thin films of carbon, aluminum oxide, and VYNS. Only those particles that emerged in the forward direction were studied. Evidence is presented for identifying the stopping cross sections per atom observed in this way with Se, the electronic component of the total stopping cross section per atom. It appears that the calculated energy dependence of [Formula: see text] is somewhat in error, and that the magnitudes of the Se's for He4 are systematically too small by 10–15%.

Ion Beam Analysis of O, N, and B Compositions in Materials Using Non-Rutherford Scattering of Protons

1988 ◽  
Vol 128 ◽  
Author(s):  
N. R. Parikh ◽  
Z. H. Zhang ◽  
M. L. Swanson ◽  
N. Yu ◽  
W. K. Chu
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ion Beam ◽  
Proton Scattering ◽  
Light Elements ◽  
Ion Scattering ◽  
Scattering Cross ◽  
Beam Analysis ◽  
Rutherford Scattering ◽  
Scattering Cross Sections

ABSTRACTElastic scattering of protons with energies from 1.5 MeV to 2 MeV was used to determine the concentration of oxygen in Y-Ba-Cu-O compound, nitrogen in GaN films, and boron in B-Si glass and other materials. Proton scattering from light elements in this energy range exhibits non-Rutherford scattering cross section, which are enhanced by a factor of 3 to 6 or more relative to the Rutherford scattering cross sections. Thus the sensitivity for the light clement detection is considerably larger than that obtained by He ion scattering.Quantitative analysis by proton scattering is discussed and compared with other methods.

Experimental study of the energy dependence of the total cross section for the 6He + natSi and 9Li + natSi reactions

2017 ◽  
Vol 48 (6) ◽  
pp. 922-926 ◽  
Author(s):  
Yu. G. Sobolev ◽  
Yu. E. Penionzhkevich ◽  
D. Aznabaev ◽  
E. V. Zemlyanaya ◽  
M. P. Ivanov ◽  
...  
Keyword(s):  
Experimental Study ◽  
Total Cross Section ◽  
Energy Dependence ◽  
Cross Section

Acoustic Scattering Cross Sections of Smart Obstacles: A Case Study

2011 ◽  
Vol 10 (3) ◽  
pp. 672-694
Author(s):  
Lorella Fatone ◽  
Maria Cristina Recchioni ◽  
Francesco Zirilli
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Space Shuttle ◽  
Scattering Problem ◽  
Plane Waves ◽  
Acoustic Scattering ◽  
Scattering Cross Section ◽  
Scattering Cross ◽  
Scattering Cross Sections

AbstractAcoustic scattering cross sections of smart furtive obstacles are studied and discussed. A smart furtive obstacle is an obstacle that, when hit by an incoming field, avoids detection through the use of a pressure current acting on its boundary. A highly parallelizable algorithm for computing the acoustic scattering cross section of smart obstacles is developed. As a case study, this algorithm is applied to the (acoustic) scattering cross section of a “smart” (furtive) simplified version of the NASA space shuttle when hit by incoming time-harmonic plane waves, the wavelengths of which are small compared to the characteristic dimensions of the shuttle. The solution to this numerically challenging scattering problem requires the solution of systems of linear equations with many unknowns and equations. Due to the sparsity of these systems of equations, they can be stored and solved using affordable computing resources. A cross section analysis of the simplified NASA space shuttle highlights three findings: i) the smart furtive obstacle reduces the magnitude of its cross section compared to the cross section of a corresponding “passive” obstacle; ii) several wave propagation directions fail to satisfactorily respond to the smart strategy of the obstacle; iii) satisfactory furtive effects along all directions may only be obtained by using a pressure current of considerable magnitude. Numerical experiments and virtual reality applications can be found at the website: http://www.ceri.uniromal.it/ceri/zirilli/w7.

Energy Dependence of the Total Cross Section for the Reaction 8He + 28Si

Exotic Nuclei ◽  
2019 ◽  
Author(s):  
Yu. E. Penionzhkevich ◽  
Yu. G. Sobolev ◽  
V. V. Samarin ◽  
M. A. Naumenko ◽  
S. S. Stukalov ◽  
...  
Keyword(s):  
Total Cross Section ◽  
Energy Dependence ◽  
Cross Section

scholarly journals Analysis of the time-of-flight neutron scattering cross-section data for light water measured at the SEQUOIA spectrometer, Spallation Neutron Source (SNS)

2020 ◽  
Vol 239 ◽  
pp. 14007
Author(s):  
Vaibhav Jaiswal ◽  
Luiz Leal ◽  
Alexander I. Kolesnikov
Keyword(s):  
Cross Section ◽  
High Temperatures ◽  
Cross Sections ◽  
Scattering Cross Section ◽  
Spallation Neutron Source ◽  
Light Water ◽  
Section Data ◽  
Scattering Cross ◽  
Thermal Scattering ◽  
Scattering Cross Sections

Thermal neutron scattering cross-section data for light water available in the major nuclear data libraries observes significant differences especially at reactor operating temperatures. During the past few years there has been a renewed interest in reviewing the existing thermal scattering models and generating more accurate and reliable thermal scattering cross sections using existing experimental data and in some cases based on Molecular Dynamics (MD) simulations. There is a need for performing new time-of-flight experiments at high temperatures and pressures, to have a better understanding of the physics involved in the scattering process that could help improve the existing TSL data. Lack of experimental thermal scattering data for light water at high temperatures led to a new measurement campaign within the INSIDER project at the Institut de radioprotection et de sûreté nucléaire (IRSN). Double differential scattering cross section for light water have been measured at the SEQUOIA spectrometer based at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory, United States. Several measurements have been carried out at different temperatures and pressures corresponding to liquid light water. Measurements at five different incident neutron energies Ei (8, 60, 160, 280 and 800 meV) have been carried out to help exploring different regions of the frequency spectrum. This paper presents the analysis of the dynamic structure factor and the derived frequency spectrum of light water. The analysis of the experimental data would provide one with better confidence, the behavior of thermal scattering cross sections for light water at high temperatures, knowledge of which is very important for the design of novel reactors as well as existing pressurized water reactors.

Modification of scattering of waves by central loading

1968 ◽  
Vol 46 (24) ◽  
pp. 2755-2763 ◽  
Author(s):  
Chin-Lin Chen
Keyword(s):  
Plane Wave ◽  
Cross Section ◽  
Cross Sections ◽  
Normal Incidence ◽  
Physical Explanation ◽  
Lumped Element ◽  
Scattering Cross ◽  
Back Scattering ◽  
Conducting Wire ◽  
Scattering Cross Sections

The problem of the scattering of a plane wave by a long, thin, perfectly conducting wire is studied. The scatterer is loaded at its center by a lumped element. The effects of the loading on the scattering of waves are investigated. Numerical results are obtained for the case of normal incidence. The results show that for relatively short wires, the back-scattering cross sections may be modified effectively by central loading, while for longer wires, the modification is rather difficult to achieve. To nullify the back-scattering cross section completely, it is necessary to use active loading if kh > 3.6. A physical explanation is also presented.

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