For a point source at the origin, the three-dimensional neutron diffusion equation be 15.4.4 comes -dv2(r)k2d¢(r) = q8(r) apply a three-dimensional fourier transform. solve the transformed equation. trans form the solution back into r-space hint the following equations are useful 1. vf(r)eikrdr -kl2f(r)ekr d? r (2)e 1 (2t)e p(r)eikr d2r (2n)e 1 2. let d(k) -ar 1 4t 3. the fourier transform of f(r) 1s (2m)2+a2