In this section you can find the results of a monte carlo simulation whose purpose is calculate the neutron energy distribution during the slowing down in an uniform medium and also the collision density.
The main hypotesis in this simulation is the isotropic scattering in the center of mass system, from that you get that after every collision the neutron energy is:
E' = E\frac{(1-\alpha) + (1+\alpha)cos\theta}{2}where θ is the scattering angle in center of mass frame, α = (A-1)/(A+1) and E is the neutron energy before the collision.
In the following images you can see the results of a simulation with neutron having a starting energy equal to 1 MeV slowing down in a medium with A = 12 (Carbon)
Energy distribution after the second collision, comparison with analitical solution 
