Spectrometry of intense fluxes of gamma radiation by means of the method of capsule-absorbers

The results presented are the methodological base of the intense gamma radiation spectroscopy applied for Chernobyl radiative pollution zone. A capsule-absorber is considered of spherical or cylindrical form having an internal cavity covered by absorbing multilayer wall. The capsule is exposed to narrow spatially uniform flux of photons. The purpose of this work is to develop a physical model and a computer code for calculating the dose in capsule´s cavity and reconstructing the gamma-spectrum according to experimentally measured doses in capsules of different wall thicknesses. The analysis is presented of theoretical description of basic processes of γ-quanta and secondary electrons interaction with matter. The level of the modern theoretical description was established-2% and processes were selected contributing the gamma dose values exceeding this level. Various methods of solving the problem of radiation transport were analyzed with regard to to peculiarities of capsules-absorbers. Representative set of calculated data has been obtained for some specific kinds of capsule-absorbers. These data have been used to compare the accuracy of gamma spectra reconstruction for different numerical methods