# Linear attenuation coefficient

### From Online Dictionary of Crystallography

##### Revision as of 09:03, 20 May 2017 by BrianMcMahon (talk | contribs) (Style edits to align with printed edition)

## Definition

The linear attenuation coefficient [math]\mu(E)[/math], or preferably [math]\mu_{TOT}(E)[/math] in cm^{-1}, is a measure of the photon beam attenuation by a material due to absorption and scattering processes and hence differs from the absorption coefficient, which is a measure of beam attenuation due to absorption processes only.

[math]\mu_{TOT}(E)[/math] is given by

[math]\mu_{tot} = \Big[{\mu\over\rho}\Big]_{TOT}\rho[/math]

where [math]\rho[/math] is the density of the material in g/cm^{3}.

## History

Coefficients for converting between these units are given by many authors [Cohen, E. R. and Taylor, B. N. (1987). *Rev. Mod. Phys.* **59**, 1121-1148; Creagh, D. C. and McAuley, W. J. (1992). *International Tables for Crystallography, Volume C*, ed. A. J. C. Wilson, Dordrecht: Kluwer; Chantler, C. T. (1995). *J. Phys. Chem. Ref. Data* **24**, 71-643].