Consider a plane of thickness $$\Delta z$$. The plane emits $$q$$ neutrons per second per unit area at a single energy and is comprised of a pure absorber. What is the angular flux at the right edge of the plane, $$\Phi(\Delta z, \mu)$$? Use your solution to give the angular flux emerging from an infinitely thin plane source. Hint: Use an integrating factor of $$\exp{(\sigma z / \mu)}$$.
The derivation of this solution is after the jump