Transformations systems and exterior actions

A recapitulation is made of theoretical results and experimental data showing the need to explicitly separate the parameter Radiation intensity and the variable Time if explanatory models are to be obtained in the study of radiation effects, and if these models are to allow extrapolation. This requirement is all the more urgent as the radiations considered are of low intensity. It is also shown that in this low-intensity region the phenomena will generally be much more complex that at high intensities and, in particular non-monotonous effects will often appear at constant dose, as a function of dose rate. Finally in non-linear systems operating under stable periodic conditions an extra parameter must be taken into consideration: the phase (moment of application of the radiation with respect to the development of the working cycle of the system studied)