Authors:J. Kim, J. Morel, M. Etcheverry, N. Coursol, D. Trubert, O. Constantinescu, S. Karamian, Yu. Oganessian, Ch. Briancon, and M. Hussonnois
Nowadays large interest is attached to the production of exotic beams and targets for nuclear structure and reaction studies. The nucleus178Hf, with is long-lived (T1/2=31 years) high-spin isomeric statel=16+ at a relatively low-excitation energy (2.446 MeV), is indeed a unique probe for studying phenomena in a new way. A wide research program has been underway in the framework of the Hafnium Collaboration which now concems around 80 scientists. Various targets have been prepared and adapted to different types of experiments. Irradiation processes with high-intensity beams, high-purity chemistry methods and isotopic separations have been developed. The obtaining of appreciable amounts of very high purity178m2Hf by isotopic separation, has made it possible for us to carry out -ray measurements with good statistics and high energy resolution with a -spectrometer, in order to use this isomer as a calibration standard in the 200 to 600 ke V energy range. For example, relative to the main -rays, energies have been determined with an absolute uncertainty of about 2 e V and photon emission probabilities with a relative uncertainty better than 1%.
Authors:D. Schumann, R. Dressler, St. Taut, H. Nitsche, Z. Szeglowski, B. Kubica, L. Guseva, G. Tikhomirova, A. Yakushev, O. Constantinescu, V. Domanov, M. Constantinescu, Dinh Lien, Yu. Oganessian, V. Brudanin, I. Zvara, and H. Bruchertseifer
The title goal was achieved using a DOWEX 50Wx8 cation exchange column saturated with La(OH)3 and ammonia solution as eluent. Hf, Ta and Lu were adsorbed on this column, whereas W remained in the solution. This chemical system may be used for fast on-line separations of element 106.
Authors:Z. Szeglowski, H. Bruchertseifer, V. Brudanin, G. Buklanov, O. Constantinescu, Dinh Lien, V. Domanov, L. Guseva, M. Hussonnois, G. Tikhomirowa, I. Zvara, and Yu. Oganessian
Some short-lived isotopes of Hf, Ta and W, synthesized at the U-400 cyclotron of JINR-Dubna, have been isolated using a previously elaborated fast continuous method of chemical isolation of element 104 from nuclear reaction products. The products were transported by a NaCl aerosol jet, from the irradiated targets to a separation device in which Hf, Ta and W were isolated by using three coupled ion-exchange columns.
Authors:Z. Szeglowski, H. Bruchertseifer, V. Brudanin, G. Buklanov, O. Constantinescu, Dinh Thi Lien, V. Domanov, L. Guseva, M. Hussonnois, G. Tikhomirova, I. Zvara, and Yu. Oganessian
The short-lived isotopes of W and their descendants have been isolated from the products of the bombardment of144Sm with24Mg by a fast continuous ion-exchange method, using HF solution media. The feasibility of this method for isolation of element 106 is discussed.