Absorption length

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:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \frac{I(x)}{I_0} = e^{ - x / \epsilon } }

The attenuation coefficient (or absorption coefficient) is simply the inverse of the absorption length; Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \mu = 1/ ==Calculating== The absorption length arises from the imaginary part of the [[atomic scattering factor]], ''f''₂. 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 }

See Also

• LBL X-Ray Attenuation Length calculator
• [http://11bm.xray.aps.anl.gov/absorb/absorb.php APS absorption calculator
• Wikipedia: Mass attenuation coefficient
• NIST tables of x-ray mass attenuation coefficient