scholarly journals Wavelength Dependence of the Zodiacal Light

1985 ◽  
Vol 85 ◽  
pp. 249-253
Author(s):  
R. Schiffer ◽  
K.O. Thielheim
Keyword(s):  
Surface Roughness ◽  
Correlation Function ◽  
Angular Dependence ◽  
Cross Section ◽  
Wavelength Dependence ◽  
Scattering Cross Section ◽  
Zodiacal Light ◽  
Scattering Cross ◽  
Exponential Correlation Function

AbstractWe calculated the scattering cross section of an ensemble of large, convex, randomly oriented particles with a slight surface roughness. If the roughness structure is described by an exponential correlation function, the degree and angular dependence of the zodiacal light reddening are well reproduced by our model.

scholarly journals Evidence that the Properties of Interplanetary Dust Beyond 1 AU are Not Homogeneous

1980 ◽  
Vol 90 ◽  
pp. 71-74 ◽  
Author(s):  
Donald W. Schuerman
Keyword(s):  
Cross Section ◽  
Heliocentric Distance ◽  
Interplanetary Dust ◽  
Scattering Cross Section ◽  
Zodiacal Light ◽  
Dust Density ◽  
Scattering Cross ◽  
Pioneer 10

Traditionally, earth-based observations of the zodiacal light (ZL) require two assumptions for further analysis: (A1) the dust density (n) is a power of heliocentric distance (R), n ∝ R−ν; (A2) the nature (scattering cross section, σ) of the dust is independent of location, σ(r,h,θ)=σ(θ). Observations from Pioneer 10 do not verify these assumptions.

Die Streuung niederenergetischer Elektronen an Methan. Das zweite Ionisierungspotential

1967 ◽  
Vol 22 (1) ◽  
pp. 11-14
Author(s):  
H. Ehrhardt ◽  
F. Linder
Keyword(s):  
Inelastic Scattering ◽  
Angular Dependence ◽  
Cross Section ◽  
Scattering Cross Section ◽  
Collision Process ◽  
Differential Scattering Cross Section ◽  
Scattering Cross ◽  
A Value ◽  
Forbidden Transition

Measurements are made of the inelastic scattering of electrons from methane into large scattering angles. The results show the appearance of a collision process at 19.5 ± 0.2 eV. From the measured angular dependence of the differential scattering cross section, this collision process is identified as an optically forbidden transition. The classification of this transition (2 sa1 → 3 sa1) and a value of the second appearance potential of methane (between 23.5 and 24 eV) are deduced from analogous transitions in neon.

scholarly journals Permutation Symmetry in Coherent Electrons Scattering by Disordered Media

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1971
Author(s):  
Elena V. Orlenko ◽  
Fedor E. Orlenko
Keyword(s):  
Electron Beam ◽  
Angular Dependence ◽  
Cross Section ◽  
Weak Localization ◽  
Coherent Scattering ◽  
Open Shell ◽  
Scattering Cross Section ◽  
Isotropic Scattering ◽  
Scattering Cross ◽  
New Type

A non-Anderson weak localization of an electron beam scattered from disordered matter is considered with respect to the principle of electron indistinguishability. A weak localization of electrons of a new type is essentially associated with inelastic processing. The origin of inelasticity is not essential. We take into account the identity principle for electron beam and electrons of the atom of the scatterer with an open shell. In spite of isotropic scattering by each individual scatterer, the electron exchange contribution has a hidden parameters effect on the resulting angular dependence of the scattering cross-section. In this case, the electrons of the open shell of an atomic scatterer can be in the s-state, that is, the atomic shell remains spherically symmetric. The methods of an invariant time-dependent exchange perturbation theory and a Green functions with exchange were applied. An additional angular dependence of the scattering cross-section appears during the coherent scattering process. It is shown exactly for the helium scatterer that the role of exchange effects in the case of a singlet is negligible, while for the triplet state, it is decisive, especially for those values of the energy of incident electrons when de Broglie’s waves are commensurate with the atomic.

An effective hydrogen scattering cross section for time-of-flight neutron experiments with simple organic molecules

2019 ◽  
Vol 52 (5) ◽  
pp. 1233-1237 ◽  
Author(s):  
Silvia Chiara Capelli ◽  
Giovanni Romanelli
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Neutron Cross Section ◽  
Wavelength Dependence ◽  
Scattering Cross Section ◽  
Scattering Data ◽  
Hydrogen Atoms ◽  
Scattering Cross ◽  
Scattering Contribution ◽  
Effective Neutron

The wavelength dependence of the effective neutron cross section for hydrogen has been investigated by measuring the transmitted total scattering cross section in urea, β-alanine, tartaric acid and polyethylene over the energy range 3 meV to 10 eV. Under the assumption that carbon, nitrogen and oxygen atoms contribute a small and invariant amount to the measured total cross section, these data represent a direct measure of the wavelength dependence of the overall scattering contribution of the hydrogen atoms to the total cross section. These experimental data can be used to apply effective wavelength-dependent corrections to neutron scattering data of hydrogen-rich simple organic compounds.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

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