Page "Electron beam lithography" Paragraph 20

The primary electrons in the incident beam lose energy upon entering a material through inelastic scattering or collisions with other electrons.

In such a collision the momentum transfer from the incident electron to an atomic electron can be expressed as, where b is the distance of closest approach between the electrons, and v is the incident electron velocity.

The energy transferred by the collision is given by, where m is the electron mass and E is the incident electron energy, given by.

By integrating over all values of T between the lowest binding energy, E < sub > 0 </ sub > and the incident energy, one obtains the result that the total cross section for collision is inversely proportional to the incident energy, and proportional to 1 / E < sub > 0 </ sub > – 1 / E.

Generally, E >> E < sub > 0 </ sub >, so the result is essentially inversely proportional to the binding energy.