The Choice of the Scattering

In GNU Archimedes the choice of the scattering is quite simple. First of all, we select randomly a scattering process and after this has been done, we compute the particle state after the scattering event. To this purpose we define the following functions

$$\Lambda_i ({\cal E}) = \frac{\sum_{j=1}^n {\cal W}_j ({\cal E})}{\Gamma}$$ (5.24)

for $i=1,2,...,N$ where $\N$ is, as before, the number of scattering taken into account during the simulation. A scattering mechanism is, then, choosed generating a number $r$ lying between 0 and $1$ and doing the following comparison

$$\Lambda_{i-1} ({\cal E}) < r <= \Lambda_i ({\cal E})$$ (5.25)

for a particle with energy $\cal E$ .