symbol: $S(E)$, units: $\pu{J m2}$, $\pu{J m2 kg^{-1}}$, $\pu{eV m2}$, $\pu{eV m2 kg^{-1}}$
https://doi.org/10.1351/goldbook.09387
Rate of energy loss of a particle with distance along its trajectory in a sample divided by the atomic density of sample atoms for a sample of infinitesimal thickness.
Notes:
- The atomic density is usually taken as the number density, \(N\), but sometimes as the mass density, \(\rho\). The stopping cross section is thus given either by \(S(E)\equiv (1/N)\rm{d}E/\rm{d}x\) or by \(S(E)\equiv (1/\rho)\rm{d}E/\rm{d}x\), where \({\rm{d}}E/{\rm{d}}x\) is the rate of loss of energy _000892_ with distance \(x\) along the particle trajectory. Note that \({\rm{d}}E/{\rm{d}}x\) is often called the stopping power, although it is not in units of power. This inconsistency for the term stopping power leads to its deprecation.
- SI unit: \(\pu{J m2}\) or \(\pu{J m2 kg^{-1}}\). Common unit \(\pu{eV m2}\) or \(\pu{eV m2 kg^{-1}}\).