Results 1 - 10 of 247
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[en] The standard describes radioactive calibration standards of the EFE type of isotopes 109Cd and 139Ce. The activity of the standards is 20 kBq for 108Cd and 100 kBq for 139Ce and the electron flux is 104 s-1 for both isotopes. The technical demands on the EFE standards, their testing, packaging, transport and storage are described. (E.S.)
[en] The radiochemical separation of no-carrier-added cerium from proton irradiated lanthanum was studied by solvent extraction using DEE, TBP and TPPO, the latter reagent being employed for the first time for separation of radiocerium from bulk of lanthanum. Distribution coefficients of cerium and lanthanum were investigated as a function of equilibrium time and concentration of HNO3. A mixture of 0.05M K2Cr2O7 and 0.1M H2SO4 was used as an oxidizing agent to improve the separation efficiency of cerium. A comparative study of the three extractants released that DEE is the best for separation of cerium from bulk of lanthanum oxide. The target was prepared by pressing. The production of 139Ce of high radionuclidic purity and chemical purity via irradiation of lanthanum oxide target at MGC-20 cyclotron with protons of energy 14.5 MeV is described. The experimental yield was found to be 153 kBq/μA · h . (author)
[en] The identification of major uptake pathways in plants is an important factor when evaluation the fate of manufactured nanoparticles in the environment and the associated risks. Using different radiolabeling techniques we were able to show a predominantly particulate uptake for CeO_2 nanoparticles (NPs) in contrast to a possible uptake in the form of ionic cerium.
[en] The cross section of (n,2n) reaction on cerium isotopes have been measured in the neutron energy of 13.5±0.0015 MeV from the D-T fusion nuclear reaction using Purnima Neutron Generator. Samples were irradiated along with In and Au monitor foils to determine the neutron incident flux and Generalised least Square estimated, best values for 140Ce (n,2n)139Ce and142Ce (n,2n)141Ce, reaction cross sections. Covariance analysis was performed for the estimated cross sections and the results were compared with the literature data and evaluated libraries. (author)
[en] 139Ce is obtained from the nuclear reaction: 139La(d,2n)139Ce. This article describes the lanthanum target and its processing after irradiation in order to get 99.9% radiochemically pure 139Ce