Elastic scattering

Scattering without significant loss of energy.

The scattering of an electron is described as elastic if a negligible amount of energy is lost by the primary electron in the process. The direction of the electron may be altered, but its energy remains essentially the same

An electron passing close to a nucleus is attracted toward the positive charge. The electron travels a hyperbolic path near the nucleus and then travels a straight line, but at some angle q with respect to the original trajectory. An electron passing closer to the nucleus is more strongly attracted by the positive charge and is therefore deflected through a larger angle. The momentum of the incident electrons is sufficient that they escape capture by the nucleus. Elastic scattering results in deflection of the incident electrons through angles up to but not much greater than 10-2 radians.

The angular deflection, qn, of the beam electron passing a distance rn from the atomic nucleus is given by the following relationship (based on a very simplistic model for scattering):

The deflection of the electron is directly proportional to the atomic number, Z, and decreases with distance from the nucleus, rn, as well as with increasing beam potential, V.