Modeling a nielsbohrium (element 107) on-line gas phase separation procedure with rhenium

As a basis for future heavy element experiments off-line tracer studies with rhenium have been carried out to model the chemical behavior of nielsbohrium (element 107) in thermochromatographic separations with oxygen as a reactive gas. A specific version of the On-Line Gas Phase Separation Apparatus, OLGA, has been developed to perform on-line chemical separations of short-lived products from heavy ion nuclear reactions, and to enable #alpha#-spectroscopic measurements of the separated products after condensation on thin foils. (orig.)Available from TIB Hannover: RO 801(94-59) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Electromagnetic and nuclear fission of "2"3"8U in the reaction of 100, 500, and 1000 A.MeV "2"0"8Pb with "2"3"8U

The folding- and azimuthal-angle and velocity distributions for the "2"3"8U fission fragments have been measured in reactions with 100, 500, and 1000 A.MeV "2"0"8Pb. These distributions were used to decompose the fission cross section into its electromagnetic and nuclear components. The fraction of electromagnetic fission was found to be 0.16#+-#0.07, 0.48#+-#0.08, and 0.60#+-#0.04, respectively. The electromagnetic fission cross section as a function of the "2"0"8Pb nucleus energy is compared with theoretical predictions. The measured fission cross section from nuclear reactions (#approx#1.5 b) is approximately constant between 100 and 1000 A.MeV. (orig.)Available from TIB Hannover: RO 801(94-39) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Chemical properties of element 105 in aqueous solution: Extractions into diisobutylcarbinol

SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

First aqueous chemistry with Seaborgium (element 106)

For the first time, chemical separations of element 106 (Seaborgium, Sg) were performed in aqueous solutions. The isotopes "2"6"5Sg and "2"6"6Sg were produced in the "2"4"8Cm+"2"2Ne reaction at a beam energy of 121 MeV. The reaction products were continuously transported by a He(KCl)-jet to the computer-controlled liquid chromatography system ARCA. In 0.1 M HNO_3/5 x 10"-"4 M HF, Sg was found to be eluted within 10 s from 1.6 x 8 mm cation-exchange columns (Aminex A6, 17.5#+-#2 #mu#m) together with the hexavalent Mo- and W-ions, while hexavalent U-ions and tetravalent Zr-, Hf-, and element 104 ions were strongly retained on the column. Element 106 was detected by measuring correlated #alpha#-decays of the daughter isotopes 78-s "2"6"1104 and 26-s"2"5"7102. For the isotope "2"6"6Sg, we have evidence for a spontaneous fission branch. It yields a partial spontaneous-fission half-life which is in agreement with recent theoretical predictions. The chemical results show that the most stable oxidation state of Sg in aqueous solution is +6, and that like its homologs Mo and W, Sg forms neutral or anionic oxo- or oxohalide-compounds under the present condition. In these first experiments, Sg exhibits properties very characteristic of group 6 elements, and does not show U-like properties. (orig.)Available from TIB Hannover: RO 801(96-56) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman