Davidyan A.P., Erjomin А.V., Erjomin V.V., Smolar V.A.

Object of the present research are models of transport of the charged particles, based on transport and diffusion approximation of Boltsman equations with sources of particles and the substance geometry, set according to a task in view. For construction of physical models it is necessary to simplify structure of Boltsman equation. For this purpose use widely applied at the theoretical analysis of the kinetic equation approximation of continuous delay. Keep within the bounds of diffusion model the concept of the centre of diffusion to which particles move along a straight line, beginning from a target surface, and then instantly isotropizate, in other words, dispersion of particles is represented stage-by-stage is entered. The diffusion model can be improved, having applied small-angular approximation at the first stage of penetration of a falling beam in a target, and having provided gradual transition of particles from small-angular group in the isotropic group. Splitting of the initial kinetic equation on two equations connected among themselves - for a beam getting into a target and diffusing particles in a target - is based on approximation of backward length of elastic dispersion. The choice of this or that model of the kinetic equation for a solved problem is defined by demanded accuracy of required characteristics of transport of the charged particles and volume of mathematical calculations. With the help diffusion approach distribution of the allocated energy and the injected charge has been received factor of backscattered electrons and protons. Among problems of medical subjects it was possible to receive distribution of an equivalent dose on depth at an exposition of organic materials and biological structures with a beam of accelerated electrons and protons, distribution termalizated positrons in biological tissues, to estimate resolution of a positron-emission tomography, to estimate effect of affinity at electron-beam polymerisations of hydrogels in creation nano-dimensional, superficial, biologically active structures