where d E Δ Δ is the energy loss of the charged particle due to electronic collisions while traversing a distance d x , excluding all secondary electrons with kinetic energies larger than Δ. If Δ tends toward infinity, then there are no electrons with larger energy, and the linear energy transfer becomes the unrestricted linear energy transfer which is identical to the linear electronic stopping power. Here, the use of the term "infinity" is not to be taken literally; it simply means that no energy transfers, however large, are excluded.