A comparative study of an oscillatory phenomenon in solid state by radiochemical and neutron diffraction methods

The isothermal oscillatory behaviour of radiation damaged crystalline chemical compounds is revealed by both radiochemical and neutron diffraction methods. Low temperature reactor irradiation experiments indicate the major role of the existence of defects in a periodic reaction of re-establishment of the parent lattice affecting both the amplitude and the frequency of the oscillations. Simple chemical compounds like CaF 2 and NaCl present the same oscillatory characteristics when examined by neutron diffraction as those obtained by radiochemical analysis in complex compounds. Comparison of the oscillations taken in the same compound by both methods reveals the strong connection between a macroscopically detected phenomenon of radiation damaged lattice and a radiochemical evidence of periodic reactions at the tracers' level. The whole phenomenon is speculated as an oscillatory variation of the properties of defects acting as dissipative structures in an open system being far from equilibrium, according to thermodynamics of irreversible processes. A modified Lotka model is being used.