Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: D. Trubert x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

This paper describes an experimental set up using an isotopic neutron source with graphite, preferably to a hydrogen-rich compound, as moderator. This low thermal flux source has been employed in PGNAA experiments. Only those elements having a high cross section can be quantitatively analyzed at low concentration levels, mainly, Gd, Cd, Sm, B and Hg; the other elements can only be probed at macroscopic levels. An application to the determination of boron content in collyria examplifies the possibilities of the technique.

Restricted access

Abstract  

The168mLu (T 1/2=6.7 min) (EC + β+) decay was reinvestigated by direct γ and γ-γ coincidence measurements using a continuous radiochemical separation from its168Hf parent produced by156Gd(16O,4n) reaction. Energies and intensities of 171 γ-transitions assigned to168Lu decay were accurately measured, among the 97 were found for the first time.

Restricted access

Abstract  

The possible use of thiocyanate and ammonium thiocyanate-hydrofluoric acid mixtures for quantitative anion exchange separation of zirconium from hafnium and niobium from tantalum and protactinium has been investigated. Distribution coefficients of zirconium(IV), hafnium(IV), niobium(V), tantalum(V) and protactinium(V) on macroporous BIO-RAD AGMP1 resin over a wide range of SCN and SCN/HF concentrations have been determined. The simultaneous presence of these two complexing agents causes a strong decrease of the adsorption phenomena.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors: D. Trubert, M. Hussonnois, L. Brillard, J. Kim, V. Barci, G. Ardisson, Z. Szeglowski, and O. Constantinescu

Abstract  

The (EC, +) decay of168Hf, produced by the156Gd (16O,4n) reaction, has been studied, with high efficiency HPGe coaxial detectors, using on-line measurements with the RACHEL setup. Off-line measurements were also carried out using catcher collection technique. Energies and intensities of 119 -lines are reported among these only two were known in the earlier study ofChu andReednick. The168Lu level scheme built on the basis of single - and X-spectra and - coincidence measurements, allows the interpretation of 79 -transitions, between 38 excited states reported for the first time.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors: F. Monroy-Guzman, D. Trubert, L. Brillard, J. Kim, M. Hussonnois, and O. Constantinescu

Abstract  

The behaviour of the elements Zr, Hf, Nb, Ta and Pa has been investigated on macroporous anion exchange resin BIORAD AGMP 1 in HF medium (from 0.02 to 2M). All the studied elements show strong adsorption properties at low HF concentration. The adsorption was found to be highly dependent on H+ and F concentrations. The distribution of possible adsorbable complexes is discussed.

Restricted access

Abstract  

Neutron activation analysis has been applied to determine the purity of super-enriched176Yb as well as a diagnostic to optimize yields from the P.A.R.I.S. mass separator at Orsay. In 25 mass separations carried out during 3 months, 910 mg of super-enriched176Yb2O3 were recovered from the original 7 g of176Yb2O3 (97.5% enrichment). Neutron activation analysis has shown that only two per thousand of the initially present174Yb remained in the super-enriched product. Using this176Yb super-enriched (99.998%) target, micro-quantities of the high spin (16+) isomer178m2Hf were produced by the (,2n) reaction at the U-200 cyclotron in Dubna. Quantities of about 2·1012 atoms of this isomer have been irradiated by thermal neutron at the ORPHEE Reactor, Saclay. Only the neutron capture giving rise to the isomeric state 25/2 of179Hf has been measured, by detection -rays of this 25.1 days isomer. A cross section of 45±5 barns was obtained for178m2Hf(n,)179m2Hf.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors: J. Kim, J. Morel, M. Etcheverry, N. Coursol, D. Trubert, O. Constantinescu, S. Karamian, Yu. Oganessian, Ch. Briancon, and M. Hussonnois

Abstract  

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 (T 1/2=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%.

Restricted access