Effective-photon scattering cross-section

1978 ◽  
Vol 22 (12) ◽  
pp. 484-488
Author(s):  
R. P. Gupta ◽  
E. Panarella
Keyword(s):  
Cross Section ◽  
Scattering Cross Section ◽  
Photon Scattering ◽  
Scattering Cross

Elastic Photon Scattering Cross Section for the H− Ion in the Asymptotic Approximation

1975 ◽  
Vol 53 (22) ◽  
pp. 2502-2505
Author(s):  
Frederick W. King
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Asymptotic Approximation ◽  
Scattering Cross Section ◽  
Photon Scattering ◽  
Scattering Cross ◽  
The Cross ◽  
Dipole Length

A comparison is made between the calculation of the elastic photon scattering differential cross section for the H− ion in the asymptotic approximation, employing both the dipole length and dipole velocity formulations. The divergence of the cross section using the dipole velocity formulation is discussed.

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.

Sign in / Sign up

Export Citation Format

Share Document