Interaction of radiation with matter: from the theory to the measurements

Radiation is detected by its interaction with matter.

Every detection system follows the same process: first, the radiation interacts with the detection medium and then the signal resulting from this interaction is read out and recorded.

These interaction processes depend on the incoming particles' type and energy.

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, and 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 why the analysis and the development of silicon detectors need extensive knowledge of physics that describes the radiation interaction with matter.

This book will briefly provide an overview of basic concepts.