Аннотация:We consider irradiation of a thin metallic foil heated by an intense heavy ion beam under the assumption that the energy deposition is volumetrically uniform. The non-stationary behavior of a foil is described by 1D-equations of gas dynamics in mass coordinates. The system of equations is governed by equation of states [Bushman:1983].It is supposed that the main contribution to thermal radiation is made by drops of metastable vapor-droplet medium which is formed at adiabatic expansion of the foil heated by heavy ions. The method for definition of dependence of complex index of liquid metals refraction on temperature and radiation wavelength from available experimental data is offered. The Lorenz-Mie theory is used for calculation of absorption and dispersion sections of separate drops.Nucleuses number evolution is described by analogy with gases kinetic theory. In the issue we have infinite system of ordinary different equations. Using of continuous function of nucleuses size distribution leads to Fokker-Plank equation (it is named Frenkel-Zeldovich equation} if we consider nucleation problem. It is known that nucleation problem solution included quasi- equilibrium distribution for nucleuses of prestalling sizes is applied for long processes.The system of ordinary different equations and Fokker-Plank equation are solved by numerical methods. Using of implicit finite-difference schemes allows reaching of quasi- stationary nucleation regimes. The absorption and the scattering coefficients at each point of vapor-droplet medium is defined by integrating on radii of all the droplets.Influence of the droplet formation onto interpretation of the experimentally measured brightness temperature is considered for thin lead foil volumetrically heated by 450MeV/u uranium ion beam having duration 50ns. Comparison with the available experimental data [Ternovoi:2007] is given.