An already existing, sub-critical arrangement made of natural uranium and water moderator has been exposed to a low intensity (≈ 10
9 ppp) proton beam from CERN-PS at several kinetic energies from ...600 MeV to 2.75 GeV. The energy delivered by the hadronic cascade induced by the beam in the device has been measured by the temperature rise of small sampling blocks of uranium located in several different positions inside the device and counting the fissions in thin probe foils of natural uranium. We find typically
G ≈ 30 in reasonable agreement with calculations, where
G is the ratio of the energy produced in the device to the energy delivered by the beam. This result opens the way to the realisation of the so-called Energy Amplifier, a practical device to produce energy from thorium or depleted uranium targets exposed to an intense high energy proton beam. Results show that the optimal kinetic is ≥ 1 GeV, below which
G decreases but is still acceptable in the energy range explored
Sorption properties of Zr, Hf, Nb, Ta and Pa at trace level towards a macroporous anion exchanger in HF–HCl media were investigated with two ion exchange methods: static (batch technique) and dynamic ...(column chromatography using the elution mode). Variations of the distribution coefficients as a function of HCl and HF concentration in the range 0.02–0.8
M for both acids are presented in the form of contour plots. Some of the most promising separation possibilities are pointed out.
The isotope
Db was produced by irradiation of a
Cm target with 106-MeV
F ions at the 15 MV MP Tandem accelerator of Orsay (France). The reaction products were continuously and rapidly transported ...with a KCl aerosol helium jet system to the chemistry setup. They were dissolved in HF medium and the solution was passed through three successive ion exchange columns, allowing a continuous high level purification of Db from actinides on a first cation exchange column, the isolation of Db on an anion exchange one, and the retention of the long-lived decay products of
Db (3.24 h–
Fm) on a second cation exchange column. Just after the end of irradiation, the decay products were desorbed from this column, purified and α-sources were prepared on carbon foil by electrospray. In 13 effective irradiation hours, 22 events corresponding to the α-decay of
Fm were recorded. Almost 70 atoms of
Db, produced in the reaction
Cm +
F were isolated in dilute HF medium. Like its homologues/analogues Nb, Ta and Pa, dubnium forms, with fluoride ions, negatively charged complexes which are strongly retained on anion exchanger.
In order to study the chemical properties of element 106 in aqueous media, fast, efficient and reproducible chromatographic separations were tested on its assumed homologues: Mo, W and U. ...Corroborative static and dynamic off-line experiments have shown that after fixation of these three elements on an anion-exchange resin in HF medium, selective elution could be achieved by using suitable concentrations of HCl-HF and HCl solutions. Separations of short-lived W isotopes, produced through heavy ion irradiation were also performed on-line.
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