**3.3 The material of irradiated object**

The material of irradiated object has an impact on the distribution of absorbed doses throughout the object. This can be explained by the difference in the number of electrons in electron shells of various atoms, which determines the nature of interaction between the accelerated electrons and matter. **Figure 3** shows the dependencies of the relative absorbed dose distribution on the penetration depth of 10 MeV electrons in aluminum, graphite, water, and polypropylene, which have different effective charge *Zeff.*

**Table 2** presents the optimal distances *Lopt* for the object made of aluminum, graphite, water, and polypropylene irradiated with 10 MeV electrons, as well as the irradiation uniformity throughout the object made of different materials, which is determined for the optimal distance *Lopt.*
