Bremsstrahlung Generation by 7.5 Mev Electrons in Converters Made of Different Materials

Abstract

The present paper shows that, besides the technologically complex water-cooled converters made of Ta or W, a simple and efficient converter in the form of air-cooled Mo and Al plates can be fabricated for a number of tasks. The generation of bremsstrahlung by electrons with the energy of 7.5 MeV in the converter plates made of Ta, W, Cu or Mo and in the Al filter was studied by the Monte Carlo method in the PENELOPE software package. The thicknesses range of the plates made of Ta, W, Cu or Mo was chosen on condition that the total mass thickness of the converter and filter made of Al (in g/mm2) provided complete absorption of the primary electrons. It is shown that the photon yields from Mo at mass thicknesses above 25 g/mm2 are higher than those from Ta and W, but the energy transferred from electrons to BS is lower. With the same mass thicknesses of Ta and W converters, practically all characteristics of bremsstrahlung and the absorbed energy in the target are the same. The conditions for cooling the converter elements with water and air are determined for the level of heat release in the converter up to 10 kW. The minimum dimensions of the electron-irradiated region of Ta and Mo converters, cooled by water, are determined. It is shown that with the really existing air compressors taken into account, the permissible heat release of air-cooled Mo converters should not exceed 4 kW.