Continuous-slowing-down range ($R_{\mathrm{CSDA}}={\int }_0^{T_0}\frac{dT}{S(T)}$)

The path-length estimate $R={\int }_0^{T_0}dT/S(T)$ obtained by replacing random losses by their mean. It is not exactly the projected penetration depth when Multiple Coulomb scattering bends tracks.