Difference between revisions of "Absorption length"
KevinYager (talk | contribs) (Created page with "The '''absorption length''' or '''attenuation length''' in x-ray scattering is the distance over which the x-ray beam is absorbed. By convention, the absorption length...") |
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The absorption follows a simple [http://en.wikipedia.org/wiki/Beer%27s_Law Beer-Lambert law]: | The absorption follows a simple [http://en.wikipedia.org/wiki/Beer%27s_Law Beer-Lambert law]: | ||
:<math> | :<math> | ||
| − | \frac{I(x)}{I_0} = e^{ - x / \ | + | \frac{I(x)}{I_0} = e^{ - x / \epsilon } |
</math> | </math> | ||
| + | The '''attenuation coefficient''' (or '''absorption coefficient''') is simply the inverse of the absorption length; <math>\mu = 1/ | ||
| + | |||
| + | ==Calculating== | ||
| + | The absorption length arises from the imaginary part of the [[atomic scattering factor]], ''f''<sub>2</sub>. It is closely related to the absorption cross-section, and the mass absorption coefficient. Specifically, the '''atomic photoabsorption cross-section''' can be computed via: | ||
| + | :<math> | ||
| + | \sigma = 2 r_e \lambda | ||
| + | </math> | ||
| + | |||
| + | ==See Also== | ||
| + | * [http://henke.lbl.gov/optical_constants/atten2.html X-Ray Attenuation Length calculator] | ||
| + | * [http://en.wikipedia.org/wiki/Mass_attenuation_coefficient Wikipedia: Mass attenuation coefficient] | ||
| + | * [http://www.nist.gov/pml/data/xraycoef/ NIST tables of x-ray mass attenuation coefficient] | ||
Revision as of 14:31, 6 June 2014
The absorption length or attenuation length in x-ray scattering is the distance over which the x-ray beam is absorbed. By convention, the absorption length λ is defined as the distance into a material where the beam flux has dropped to 1/e of its incident flux.
Absorption
The absorption follows a simple Beer-Lambert law:
The attenuation coefficient (or absorption coefficient) is simply the inverse of the absorption length;
![{\displaystyle \mu =1/==Calculating==Theabsorptionlengtharisesfromtheimaginarypartofthe[[atomicscatteringfactor]],''f''<sub>2</sub>.Itiscloselyrelatedtotheabsorptioncross-section,andthemassabsorptioncoefficient.Specifically,the'''atomicphotoabsorptioncross-section'''canbecomputedvia::<math>\sigma =2r_{e}\lambda }](https://wikimedia.org/api/rest_v1/media/math/render/svg/dbdde8072ba4dc078de916b088a6cf9c8584f6a6)
