Particle interactions with matter

With the steady advances in accelerator technology and new records in beam energy, intensity, brightness, power and luminosity, it is essential to limit adverse effects of beam losses for accelerator operation, equipment and personnel. Particle losses can quench superconducting magnets, induce single event effects in electronics, activate equipment, and alter material properties. In the worst case, high-energy particle beams can cause severe damage to equipment if they are lost in an uncontrolled way. Modern accelerators typically rely on a system of protection absorbers, dumps and beam manipulation devices to safely accelerate, store, extract and transfer beams. Knowledge of particle-matter interactions is important to understand and predict the consequences of beam losses and to design beam-intercepting devices, shielding and other equipment. This paper summarizes the principal physical processes of hadrons, photons and leptons in matter and discusses related phenomena such as particle showers.