Effective attenuation length

Effective atomic number rule, 76 60-61 Effective attenuation length (EAL), 24 88-89... 

Effective attenuation length beneath inclined or partially shaded surfaces. As the attenuation length A for cosmogenic nuclide production by spallation (Eqn. 20) is determined by the angular cosmic ray neutron distribution, it increases when part of the... 

The effective attenuation length is a function of electron kinetic energy and of the medium density. However, when we represent A. in number of monolayers, an approximately universal curve is obtained [32] as displayed in Figure 12. 

Fig. 12. Schematic representation of electron effective attenuation length as a function of electron energy.

C.J. PoweU and A. Jablonski, Electron Effective Attenuation Length Database, Version 1.0 (SRD 82), US Department of Commerce, National Institute of Standards and Technology, Gaithersburg, 2000. 

In order to derive a composition or thickness from peak intensities, certain parameters characterizing the sample are typically needed. They enter the particular equation used for analysis [5, 6]. Examples of such parameters are the inelastic mean free path (IMEP) or the effective attenuation length (EAL) (defined below). Clearly, the uncertainty of the final result will depend on the validity of the model and the equation used for the particular specimen morphology, uncertainties of the measured peak intensities [6], and uncertainties of the sample-parameter data. 

DDFs can be calculated from Eq. (3.2.3.2) by specifying the experimental configuration (the angle a and the angle P between the direction of the X-rays and the direction of the analyzer) and parameters for particular photoelectrons from a given solid (/3, Xin, and Xtr). Since the formalism is rather complex, DDFs can be obtained more conveniently from the NIST Electron Effective-Attenuation-Length Database (SRD 82) [41]. 

A. (2011) NIST Electron Effective-Attenuation-Length Database,... 

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