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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 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 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  

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  

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  

A radiochemical separation is presented for americium, plutonium and neptunium from sediment samples by using an unique anionic exchange process. An oxidation-reduction step was introduced in the classical procedure of the radiochemical determination of transuranic elements in order to control the valence of the separated elements.

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Abstract  

The decay of228Ac has been reinvestigated by means of high resolution HPGe detectors. Accurate energies and intensities of 242 photons were measured, of which 80 were found for the first time.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
M. Kouassi
,
J. Dalmasso
,
H. Maria
,
G. Ardisson
, and
M. Hussonnois

Abstract  

The decay of a225Ac source in equilibrium mixture with its decay products was investigated using high-resolution HP/Ge/ detectors. Energies and intensities of more than 78 -photons were measured with an improved accuracy; 44 of them are reported for the first time. A tentative221Fr level scheme was built on the basis of good energy sum relationships; seven new221Fr excited levels are proposed at 496.9, 570.9, 603.5, 630.7, 637.7, 649.0 and 758.9 keV.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
M. Kouassi
,
J. Dalmasso
,
M. Hussonnois
,
V. Barci
, and
G. Ardisson

Abstract  

The -decay of225Ac to221Fr excited states has been reinvestigated using high-resolution -spectroscopy for single and - coincidence measurements. Twenty nine221Fr nuclear excited states were proposed; ten of which are newly observed.

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Abstract  

238Pu, 239-240Pu, and 241Am were measured, by -counting after radiochemical separation, in two lake sediment cores. The profiles of these transuranics were compared to those of the fission product 137Cs. Datation of nuclear events and data on behavior of the studied elements were deduced.

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