At research nuclear reactors, isotopes for various purposes including sources of beta radiation are accumulated. When handling with high energy sources containers made of heavy materials (for example lead, tungsten)are used. They have good protective properties but when braking beta radiation, powerful secondary gamma radiation can occur bremsstrahlung. The article describes the mechanism of occurrence of bremsstrahlung. A model of the process is described, its regularity is formulated, and the dependence of the electron energy loss in the material is derived. A diagram of radiation, ionization, and total losses for tungsten is presented. The thicknesses of materials are determined at which the kinetic energy of an electron is completely consumed. The part of energy converted to bremsstrahlung is calculated. Based on the data obtained, an option is proposed to create protection when handling beta sources.