The fission yields obtained show a high degree of reliability. The time needed is about one-tenth of that of previous methods.
The use of the nonisotopic carrier more » makes possible yield measurements of short-lived nuclides. The elements are thereafter separated from each other by cation exchange chromatography using ammonium lactate as eluant. A further group purification is obtained by an anion exchange step. Lanthanum is used as carrier in fluoride and hydroxide precipitations for group isolation of all the lanthanides that are formed. On this basis a radiochemical method for the determination of nuclear reaction yields was developed. The results show that lanthanum under the given conditions carries trace lanthanum and lanthanides to the same extent. The use of lanthanum as a common carrier for all lanthanides was studied. Still others were irradiated in the Coupled Fast Reactivity Measurements Facility at INEL. Other samples were irradiated at the Los Alamos Cockcroft-Walton and Van de Graaff accelerators. Most samples were irradiated in the following Los Alamos reactors: BIG-TEN, Clementine, Flattop (oralloy core), Flattop (Pu more » core), Godiva-I, Godiva-IV, Jezebel (Pu core), Jezebel (/sup 233/U core), Topsy, Tungsten-Carbide Critical Assembly, and Water Boiler. Finally, the relative fission yields were converted to absolute values. The circumstances associated with inconsistencies were investigated, but the yields in questions were rejected only when good cause was found. The yields were examined for consistency by means of the two-mode-of-fission hypothesis. Radiochemically measured relative fission yields have been compiled for targets of /sup 232/Th, /sup 235/U, /sup 236/U, /sup 237/Np, /sup 238/U, and /sup 239/Pu that were irradiated with neutrons, the average energies of which were in the 0.0253-eV to 14-MeV range. C-INC has performed an HEU irradiation and also 'cold' carrier analyses by ICP-AES to determine methods for rapid and reliable separations that may be used to detect and quantify low-yield fission products by gamma spectroscopy. This work demonstrates the effectiveness of the separations for the intended application of short-lived lanthanide fission product analysis requiring high decontamination = Tb. Based on the results obtained here, the fission yields for 144Ce, 153Sm, 156Eu, and 161Tb are consistent with published fission yields. The separations were performed in parallel in quadruplicate with reproducible results and high decontamination factors for 153Sm, 156Eu, and 161Tb. In this work, the method was demonstrated for the separation and quantification of multiple short-lived fission product lanthanide isotopes from a fission product sample produced from the thermal irradiation of highly enriched uranium. In a previous paper, the authors reported the optimization of an intra-group lanthanide separation using LN extraction resin from Eichrom Technologies®, Inc. The measurement of radioactive fission products from nuclear events has important implications for nuclear data production, environmental monitoring, and nuclear forensics.