stopping power

Stopping power refers to the rate at which a charged particle loses energy as it travels through a medium. This energy loss occurs through interactions with the atoms and molecules of the medium, primarily causing ionization and excitation.

Niels Bohr developed an early equation for stopping power, which is expressed as the product of a kinematic factor and a stopping number. The kinematic factor considers properties like the particle's charge and velocity, and the medium's atomic density. The stopping number involves the atomic number of the medium and logarithmic terms related to the particle's velocity and charge.

For heavy charged particles, Hans Bethe's quantum mechanical approach provides a more detailed stopping number. For electrons, the stopping power is also described by complex expressions, with relativistic effects becoming significant at high velocities. The concept of stopping power is crucial for understanding how radiation interacts with matter.12