Beta Particle:

The beta particle is a usual electron or positron ejected from the nucleus of a beta-unstable radioactive atom. A beta has a one negative or positive electrical charge and an extremely small mass.

An interaction of a beta particle and an orbital electron leads to electrical excitation and ionization of the orbital electron. Those interactions cause the beta particle to lose energy within overcoming the electrical forces of the orbital electron. An electrical forces act over long distances; thus, the two particles do not have to come into direct contact for ionization to occur.

The amount of energy lost through the beta particle depends upon both its distance of approach to the electron and its kinetic energy. A Beta particles and orbital electrons have the similar mass; thus, they are simply deflected through collision. Since of this reality, the beta particle follows a tortuous path as it passes by absorbing material. The exact ionization of a beta particle is low due to its small charge, small mass, and associatively high speed of travel.