]> ${\mathrm{\&CapitalIota;}}_0\approx \frac{R_{\Lambda }}{4\Pi D^2}{e}^{-{\rm M}D}=\mathrm{\&FreakedSmiley;}$


I₀ is the radiation dose received at a distance D from a nuclear explosion. $R_{\Lambda }\text{is the initial total radiation release, and}{\rm M}\text{is the attenuation factor in air. (e and}\Pi$ are mathematical constants). Ref: "The Effects Of Nuclear Weapons", US Dept. of Defense, April 1962, section 8.98.