Extraction of short-lived zirconium and hafnium isotopes using crown ethers: A model system for the study of rutherfordium

Abstract

Zirconium / Hafnium / Crown ether / Liquid-liquid extraction / Distribution ratio / Separation factor SummaryThe extraction of zirconium and hafnium from hydrochloric acid media was studied using the crown ethers dibenzo-18-crown-6 (DB18C6), dicyclohexano-18-crown-6 (DC18C6) and dicyclohexano-24-crown-8 (DC24C8) as extractants. The goal was to find an extraction system that exhibits a high selectivity between the members of group 4 of the periodic table and is suitable for the study of rutherfordium. It was found Rf.

Gas chemical investigation of hafnium and zirconium complexes with hexafluoroacetylacetone using preseparated short-lived radioisotopes

“…Catcher foils of 25-μm thick household Al foil were attached to the holder. All nuclear reaction products (except the scattered 18 O beam) entering the RTC (which was kept at a pressure below 0.1 bar for these experiments) were stopped inside the catcher foils, as was predicted by SRIM-2003 [60] calculations and confirmed experimentally. These reaction products could be brought to the counting area outside the cave within about 90 s after the end of bombardment.…”

“…Over the course of about two years, relatively shortlived isotopes of Zr and Hf were studied in eighteen short blocks (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32) nat Ge, all in the elemental form, were used. They were produced by vacuum deposition from a resistively heated source.…”

“…They were produced by vacuum deposition from a resistively heated source. Table 1 lists the properties of the used targets along with the EVRs of interest produced in complete fusion reactions with the 18 O beams (targets #1 and #2) and 50 Ti beams (#3 to #6). Hereafter, the targets are referred to according to their entry in column 1 in Table 1.…”

“…The beam-free environment promises to allow studying thermally unstable chemical species. The absence of most unwanted background species was already exploited in liquid phase studies of rutherfordium (Rf,element 104) [11,16,17] where physical preseparation from isotopes that interfere with the unambiguous identification of single atoms of the heaviest elements through detection of their characteristic radioactive decay was essential, and in extraction studies of group 4 elements with crown ethers [18]. The potential that physical preseparation offers in the field of TAN chemistry has been recognized and has led to the upgrade of existing recoil separators such as i) the Berkeley Gas-filled Separator (BGS) [19] installed at the Lawrence Berkeley National Laboratory, Berkeley, CA, US [12,15], ii) the GAs-filled Recoil Ion Separator (GARIS) [20,21] at the RIKEN laboratory, Wako, Saitama, Japan, and iii) the Dubna Gas-Filled Recoil Separator (DGFRS) [22] at the Flerov Laboratory of Nuclear Reactions, Dubna, Russia, so that they can now be used as preseparators.…”

“…An independent possibility to check for non-chemically selective transport is offered by the investigation of 86m Y. This isotope in its isomeric state is produced in pxn exit channels in the 18 O + nat Ge and 18 O + 74 Se reactions (see Fig. 3 in [12]) and easily detectable.…”