Neutron beam hitting Uranium 238 foil

[Steven Brown]

Homework Statement

A high energy beam of neutrons of intensity 10^6 s^-1 transverses a target of 238 U of thin foil whose density per unit area is 10^-1 kg m^-2. If the elastic and in elastic cross-sections are 1.4 and 2.0 b, respectively, calculate(a) the attenuation of the beam(b) the rate of elastic reactions and(C) the flux of elastically scattered neutrons 5 m from the target, averaged over all scattering angles.

Homework Equations

flux J=NbVi
Wr=jNsigma, r
The reduction in beam intensity on crossing the segment is is equal to the reaction rate dW within the segment
AdJ(x)=-dW
dW=j(x)sigma nt Adx

The Attempt at a Solution

 

[Steven Brown]

tried integrating over the input Ji exp (-x/ln)sigma nt Adx and I am totally stumped