ABSTRACT
Then, 8πre2/3 is obtained. Rayleigh scattering results when the electron is bound with an atom
and not a free electron. Because all atomic electrons behave similarly, the radiation scattered by the individual bound electrons of a given atom will be coherent-i.e., capable of showing constructive or destructive interference. This type of scattering is also called coherent scattering. Similar to Thomson scattering, the de±ection angle is very small and energy loss is nothing. The differential cross section is represented using the Thomson cross section,
d d
( , ) d d
coh 2F Z v T σ
=
σ (12.3)
where Z is the atomic number and v is a parameter that represents the momentum transfer to an atom. If photon energy hν is in a keV unit, v is written by in angstrom unit:
12.4 sin
2 Å 1v
h =
ν θ − (12.4)
EXAMPLE 12.1
Calculate the parameter v for the momentum transfer for the incident photon of energy 1 MeV scattered through the angle 45° relative to the beam’s direction.
