Penetration and Diffusion of X-Rays through Thick Barriers. II. The Asymptotic Behavior when Pair Production Is Important

The methods of a previous paper are modified to cover the high energy x-rays which are strongly absorbed by pair production. The variation of intensity with depth of penetration is then expected to follow a law of the type $x^{-\frac{5}{6}}\exp (-{\mu }_{m}x+b{x}^{\frac{1}{3}})$.