A model for the time dependence of the equivalent mass attenuation of ββ rays in fission production

By analyzing a number of experimental data from radioactive fallout samples, the paper puts forward a new kind of theoretical model for the time dependence of the equivalent mass attenuation coefficient of ββ rays in fission product. The calculated data by using the formulae derived from the model are in conformity with the experimental data, taken from another batch/set of fallout products. The decay time of the formula is available from 4 to 800 h.