binary encounter approximation

binary encounter approximation

[′bīn·ə·rē in′kau̇nt·ər ə‚präk·sə′mā·shən]
(atomic physics)
An approximation for predicting the probability that an incident proton will eject an inner shell electron from an atom; it uses a semiclassical treatment of momentum transfer from the incident proton to the ejected electron.