NEWS dow of the cell is a tank with two thick Incite faces filled with distilled water. A refinement on bag pass and transfer port manipulation was also described. The cell is provided with master slave manipulators. J. Kooi, Euratom, European Transuranium Institute, described an extremely simple extraction chromatographic procedure for the separation and purification of curium, americium, berkelium, and californium from fission products such as ruthenium, strontium, cesium, cerium, rhodium, and europium. In this separation a kieselguhr column loaded with di-2-ethylhexyl orthophosphoric acid was used. Separation of curium, americium, and a number of rare earths as EDTA complexes was achieved by electrophoretic separation at high voltage. The mobility of the various metals was shown to be dependent on the pH, stability of the metal complex, and the concentration of the complexing agent. In a medium containing EDTA, buffered with aminoacetic acid to pH 1.6, a good separation of Am-Cm from the rareearth elements was obtained. In the separation of americium and curium from the lanthanide elements by tertiary amine extraction from concentrated solutions of lithium chloride, two important chemical changes in solutions occur as a result of alpha radiolysis. The rate of depiction of acid and rate of formation of oxidants was reported by D. A. Costanzo, Oak Ridge National Laboratory, to be equal to 1 megawatt-hour of exposure to alpha radiation for a slightly acid 10M LiCl solution containing curium-242. The loss of acid ultimately results in the precipitation of actinide elements and fission product impurities. The formation of oxidants converts the cerium to the extractable tetravalent state and results in poor cerium decontamination. The radiolytic effects on concentrated solution of lithium chloride effects observed at high levels of alpha activity result in formation of radiolytic gases, such as molecular chlorine, hydrogen, and oxygen. Costanzo described the use of methanol to inhibit the loss of acid due to radiolysis. R. D. Baybarz, Oak Ridge National Laboratory, evaluated twenty polyaminopolycarboxylic acids as to selective chelation for group separations of the transplutonium elements from the lanthanide elements. Distribution coefficients of americium, californium, cerium, and europium between 0.3M di-2-ethylhexyl phosphoric acid on dicthylbenzene and 0.5M solution of the
chelating agents in \M lactic acid were shown. The maximum Eu-Am separation obtained was 100 with diethylenctriaminepentaacetic acid. Chloro substitution for hydrogen on the acetyl radical diminished the effectiveness of the chelating agents. The maximum Eu-Cf separation factor obtained was 10 with 1,2-diaminocyeIohexane-tetraacetic acid. Substitution of a benzene ring for the cyclohexane ring diminished the effectiveness of the chelate. R. J. Morrow, Lawrence Radiation Laboratory, Livermore, described an anion exchange procedure for the separation of americium and curium from large quantities of dissolved salts from alcoholic H N 0 3 and HCl media. This method proved particularly useful in separations from debris of underground nuclear explosions. Distribution coefficients are generally larger for the alcoholic system than for the corresponding lithium salt system. A second advantage of the alcoholic system is that the actinide elements can be absorbed onto the anion resin column and many interfering cations can be washed from the column. M. Y. Donnan, Savannah River Laboratory, E. I. du Pont de Nemours, discussed an electrodeposition method for the preparation of alpha sources for precise alpha counting and pulse height analysis. In this method quantitative cathodic electrodeposition is effected in an isopropyl alcohol medium containing ammonium chloride as the electrolyte and uranium as a carrier. This technique was applied routinely to deposit actinides from 11M LiCl and organic phosphate solutions that could not be evaporated to give amounts suitable for alpha counting. R. E. Eby, Oak Ridge National Laboratory, obtained a half life of 2.49 ± 0.06 years for 2B2Cf based on mass spectrometric analysis, which is in good agreement with previously published data. The half-life was checked by analyzing a series of californium samples, each containing 3 to 5 nanograms of Cf at about 90-day intervals. The half life of the other Cf isotopes were then determined from the Cm isotopic analyses. Eby also described the use of a special two-stage, 12-inch, 90° spectrometer to analyze 3 to 5 nanograms of radioactive samples. The system is equipped \vith an electron multiplier and pulse counting equipment. The magnets and vacuum system assembly are installed on an alpha containment laboratory. The instrument has been used to analyze all transuranium elements through californium.
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VOL. 38, NO. 2, FEBRUARY
1960
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