Attenuation length

Inphysics,theattenuation lengthorabsorption lengthis the distanceλinto a material when theprobabilityhas dropped to1/ethat aparticlehasnotbeenabsorbed.Alternatively, if there is abeam of particlesincident on the material, the attenuation length is the distance where theintensityof the beam has dropped to1/e,or about 63% of the particles have been stopped.

Mathematically, the probability of finding a particle at depthxinto the material is calculated by theBeer–Lambert law:

$P(x)=e^{-x/\lambda }\!\,$.

In generalλis material- and energy-dependent.

See also

• Beer's Law
• Mean free path
• Attenuation coefficient
• Attenuation (electromagnetic radiation)
• Radiation length

References

• S. Eidelman; et al. (2004). Particle Data Group (ed.)."Review of particle physics".Phys. Lett. B.592(1–4): 1–5.arXiv:astro-ph/0406663.doi:10.1016/j.physletb.2004.06.001.PMID10020536.S2CID118588567.
• https://web.archive.org/web/20050215215652/http://www.ct.infn.it/~rivel/Glossario/node2.html

External links

• http://henke.lbl.gov/optical_constants/atten2.html