Radiation is detected by its interaction in matter. Every detection system has the same structure: it starts with the interaction of the radiation with the detection medium; interaction generates signal that is read-out and usually recorded. These interaction processes depend on both the type and the energy of the incoming particles.
Physical phenomena allowing detection often involve soft electrons or photons, or atomic and molecular excitations. The fundamental mechanism on which radiation detectors are based is the dissipation of a fraction of the incoming radiation energy inside the detecting material. The transferred energy spreads among excited states, which are capable of generating carriers, e.g. electrons-holes in semiconductors, ion pairs in gaseous devices, photons in scintillating media. Read-out elements process these carriers (e.g. front-end electronics in semiconductor detectors). Hence, the required radiation information, such as momentum, energy and velocity, is obtained.
This is the reason why the analysis and the development of silicon detectors needs an extensive knowledge of the physics that describe the radiation interaction with matter.
Following will be briefly addressed an overview of basic concepts.