20.3.6 The 1-D neutron diffusion equation with a (plane) source is -D \frac{d^{2} \varphi(x)}{d x^{2}}+K^{2} D \varphi(x)=Q \delta(x) \text { where } \varphi(x) \text { is the neutron flux, }

Q \delta(x) \text { is the (plane) source at } x=0, \text { and } D \text { and } K^{2} \text { are } constants. Apply a Fourier transform. Solve the equation in transform space. Transform your solution back into x-space.