Approximations to multiple Coulomb scattering

The width of the angular distribution of the multiple Coulomb scattering of relativistic heavy particles can be described by simple formulas. The familiar one, which uses the number of radiation lengths, is accurate to 34% for all Z and can be accurate to 11% if a logarithmic path length correction is included. A fairly simple representation that does not use the radiation length agrees with the predictions of Moliere scattering to 2%.