X-ray depth doses from linear accelerators in the energy range from 10 to 32 Mev

The depth dose characteristics of the x-ray beam from a linear accelerator have been studied in the electron energy range from 10 to 32 MeV for various target and flattening filter combinations. At all energies the most penetrating x-ray beam is obtained with a low atomic number flattening filter. At energies below 15 MeV a high atomic number target should be used, while at energies above 15 MeV a low atomic number target should be employed to get the best depth dose distribution. The optimum target thickness is approximately equal to the mean range of electrons in the target material. The study of some physical parameters such as depth dose, average dose, and integral dose, suggests that the optimum energy for linear accelerators used in the x-ray mode is about 25 MeV.