出典:Wikipedia
出典:『Wikipedia』 (2010/02/27 17:58 UTC 版)
In physics, the attenuation length or absorption length is the distance λ into a material when the probability has dropped to 1 / e that a particle has not been absorbed. Alternatively, if there is a beam of particles incident on the material, the attenuation length is the distance where the intensity of the beam has dropped to 1 / e, or about 63% of the particles have been stopped.