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  • Author or Editor: G. Ardisson x
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Abstract  

Energies and intensities of more than 192 gamma-transitions were accuratelymeasured, 63 of these are reported for the first time. The 237Nplevel scheme built on the basis of good sum relationship accounts for 165transitions de-exciting 46 excited levels; 6 are proposed for the first time:at 712.7, 759.4, 945.3, 962.3, 1015.2 and 1114.3 keV. Spin and parities ofthe new states were discussed in the framework of the Nilsson's model.

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Abstract  

Long-lived fission radionuclides spread out after the Chernobyl accident have been measured in samples collected from the Black Sea and at the Aegean coasts of Turkey between June 15 and September 15, 1987. Nondestructive analysis was performed using high resolution -spectroscopy. The activity remaining 16 months after the event was found to be enhanced in coniferous needles as well as in lichens, while foodstuff did not show any appreciable contamination. The relatively high106Ru/134Cs and144Ce/134Cs ratios compared to those found in analogous samples from Southern Europe, might result from a fractionation between refractory and volatile elements.

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Abstract  

The decay of234Pa(UZ) was reinvestigated using high-resolution coaxial and planar HPGe detectors. Accurate energy and intensity values of 327 photons are given, of which 144 previously unobserved.

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Abstract  

233U -decay was reinvestigated using a radiochemically purified source and high efficiency HPGe coaxial detectors; the lowenergy -spectrum was also measured using a LEPS detector. The energy and intensity values of one hundred sixty three -lines were determined, from which forty eight are newly reported with respect to the last study of Canty et al. A revised229Th level scheme was built, using the Ritz combination principle, in which nine levels are newly observed, at 371.3, 381.8, 465.5, 569.2, 584.9, 605.1, 620.8, 656.9 and 749.9 keV.

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Abstract  

Actinides activity levels deposited after the Chernobyl accident on the coastal Mediterranean area at Monaco have been recently measured (1). The values obtained are low. However, our -measurements on humic soils from the southern Alps revealed high137Cs level contamination areas and urged us to evaluate241Pu activity levels. The indirect determination of241Pu was based on the -activity measurement of the241Am in situ ingrown.

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Abstract  

A50Sc cluster emission from249Cf has been found compatible by a previous prediction byGupta.

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Abstract  

After the reactor accident at Chernobyl, samples of soil, moss, lichen and fern were collected in the forest around the Vesubie valley in the South East of France and analyzed by low energy photon and gamma spectrometry. Activity concentrations as high as 42.8, 9.4 and 3.8 kBq.m–2 were measured for137Cs,134Cs and106Ru, respectively, in soil, in October 1988.125Sb and110mAg were also detected. The contamination was found to be the most important between 1400 and 1700 m altitude.

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Abstract  

The radioactivity of various terrestrial vegetation leaves characteristic of Mediterrenean countries has been measured after the Chernobyl accident. In addition, we paid particular attention to lichens and seaweed which are considered as bioindicators of radioactive contamination. The measurements were performed by non-destructive way using both coaxial and planar HPGe detectors. For odd mass radionuclides having low energy lines, such as125Sb or141Ce the sensitivity of the planar HPGe detector is better than the coaxial detector. The concentration of long lived fission nuclides remaining three months after the accident were found to be enhanced in needle form leaves and in lichens. The seaweed Sphaerococcus exhibits a strong specific activity for iodine and ruthenium and poor concentration for cesium nuclides. The activity ratios of different isotopes of the same element, measured in vegetation samples agree well with the values found by other authors in airborne aerosols. The activation nuclide110Agm is found in all samples with the same ratio110Agm/137Cs=/1.0±0.2/×10–2, as in the soil deposition.

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Abstract  

The decay of166Hom has been reinvestigated on radiochemically separated sources with the aid of high efficiency HPGe detector. Energies and intensities of 54 γ-lines, of which 10 are new, were carefully measured. All γ-rays can be interpreted as deexciting known166Er levels.

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Abstract  

The -spectrum following the -decay of249Cf was reinvestigated using high resolution coaxial and planar HPGe detectors. Accurate energy and intensity values of 44 -rays were measured, among which 23 were reported for the first time.

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