The program simulates attenuation of a particle-beam, where the particles interact with the material only with low probability. Therefore they interact only not more than once, and if they interact, they disappear from the beam. In the simulation they get absorbed. The photons of gamma-radiation are good examples of this type of particles (although they get also scattered out of the beam, not only absorbed). The interaction (absorption) probability density refers to the unit path length in the material, therefore its measure is [1/cm].

In the upper-right field of the screen the particle beam arrives from the left, and falls on a gray-colored block of material, where the particles may interact with the matter with the interaction probability density given in the left part of the screen. The graph in the right-bottom shows the number of particles reaching different depths of the material. The observed fluctuations are caused by the statistical nature of the phenomenon. Read more...