In physics, the attenuation length or absorption length is the distance into a material when the probability has dropped to 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, or about 63% of the particles have been stopped.
Mathematically, the probability of finding a particle at depth x into the material is calculated by Beer-Lambert law:
- .
In general is material dependent.
Famous quotes containing the word length:
“At length to hospital
This man was limited,
Where screens leant on the wall
And idle headphones hung.
Since he would soon be dead
They let his wife come along
And pour out tea, each day.”
—Philip Larkin (1922–1986)