**1. Introduction**

Irradiation with accelerated electron beams is a convenient all-purpose technology for the processing of various biological objects and materials since it offers undeniable advantages, such as the ability to vary the beam intensity and penetration depth of electrons, minimal changes in the temperature and pressure, as well as the absence of negative effects of chemical compounds, which allows to solve a wide range of tasks, from plant growth stimulation to increasing the wear resistance of metals [1]. Electron beam irradiation of objects is enabled by the transfer of the energy to molecules and atoms of substance of irradiated object. As electrons act on the substance, ionization, and excitation of atoms and molecules lead to physical and chemical reactions that change the properties of the object. One of the main factors that determine the effect of accelerated electrons on the substance is the irradiation dose, which is the ratio between the energy absorbed by the volume and its mass [2, 3]. The research discusses the application of electron beams for processing biological and non-biological objects and establishes the dose ranges and physical properties of electron beams to solve various tasks.

Since objects and materials have diverse properties, the dose distribution throughout irradiated objects differs considerably, even if the same irradiation method is applied, depending on the chemical composition, density, and shape of the objects. The research discusses the influence of physical and chemical properties as well as electron energy on the distribution of absorbed dose over the volume of object.

The dose distribution in various objects can be simulated using transport codes [4], provided that all physical and technical parameters of the irradiation method are accurately reproduced, taking into account the individual properties of biological objects and materials. The study compares different transport codes used for irradiation simulation and presents an algorithm for simulating irradiation exposure using the GEANT4 tool kit [5–8], which is by far the most accurate tool for obtaining the absorbed dose distribution in objects of any geometry and chemical composition when irradiated with accelerated electrons.

Considering that it is not always possible to obtain the beam energy spectrum from manufacturers of electron accelerators, it is crucial to have algorithms for reconstructing the beam spectrum of accelerators used by irradiation facilities [9–14]. The study presents an algorithm to reconstruct the electron beam spectrum and the depth dose distribution in an object of any chemical composition and shape, based on the experimentally measured absorbed dose distribution in any known substance.

Since biological objects have complex biochemical compositions and geometry, they are highly sensitive to the lack of dose uniformity [15–17]. The research presents a method of electron beam modification using aluminum modifier plates to significantly improve the irradiation dose uniformity, which makes it possible to increase the spectrum of biological objects irradiated with electron beams.
