RESUMO
Direct alpha-energy spectroscopy in liquids is possible by placing a chemically selective polymer thin film upon the surface of passivated silicon diodes. By utilizing polymer thin films with high affinity for actinides, we have been able to selectively concentrate actinides of interest upon the diode surface, resulting in a substantial increase in sensitivity relative to a direct measurement. With this film coated diodes, we were able to obtain in-situ alpha spectra with energy resolution comparable to that of conventional alpha-spectroscopy. The response of the thin film coated diode was found to be linear over . The sensitivity and reversibility is a function of the membrane complexation chemistry.
Assuntos
Animais , Análise de Ativação de Nêutrons , Urânio/administração & dosagem , AvesRESUMO
The accumulation and microdistribution of uranium in the bone and marrow of Beagle dogs were determined by both neutron activation and neutron-fission analysis. The experiment started immediately after the weaning period, lasting till maturity. Two animal groups were fed daily with uranyl nitrate at concentrations of 20 and 100 microg g(-1) food. Of the two measuring techniques, uranium accumulated along the marrow as much as in the bone, contrary to the results obtained with single, acute doses. The role played by this finding for the evaluation of radiobiological long-term risks is discussed. It was demonstrated, by means of a biokinetical approach, that the long-term accumulation of uranium in bone and marrow could be described by a piling up of single dose daily incorporation.