[en] A study has been carried out for the extraction of uranium from phosphoric acid produced in Algeria. First of all, the Algerian phosphoric acid produced in Algeria by SONATRACH has been characterised. This study helped us to synthesize a phosphoric acid that enabled us to pass from laboratory tests to pilot scale tests. We have then examined extraction and stripping parameters: diluent, DZEPHA/TOPO ratio and oxidising agent. The laboratory experiments enabled us to set the optimum condition for the choice of diluent, extractant concentration, ratio of the synergic mixture, oxidant concentration, redox potential. The equilibrium isotherms lead to the determination of the number of theoretical stages for the uranium extraction and stripping of uranium, then the extraction from phosphoric acid has been verified on a pilot scale (using a mixer-settler)

[en] The elastic scattering cross section 12C - 12C has been measured in the angular range between 2⁰32 and 39⁰09 in the C.M. system at Esub(lab) = 360 MeV, with a magnetic spectrometer of constant dispersion. The focal plane detector consists of a multiwire proportional chamber coupled to a ionisation chamber for the measurements of positions and energy loss. Time of flight information was obtained by means of a large plastic scintillator coupled to a photo-multiplier placed behind the chambers. The results presented are obtained from an optical model analysis and a simplified semi-classical Glauber approach. These results confirm the presence of a nuclear rainbow wich is discussed in details, and suggest that the observed energy dependance of σsub(R) reflects the dominance of constituent nucleon-nucleon collisions in this nuclear interaction, and agree with theoretical predictions based on Glauber Theory

No abstract available

[en] Electric field magnitude and depletion in the bulk of silicon pixel detectors, which influence its breakdown behaviour, was studied using finite-element method to solve the drift-diffusion equation coupled to Poisson's equation in a simplified two dimensional model of the ATLAS pixel sensor. Based on this model, the number of guard rings and dead edges width were modified to investigate their influence on the detector's depletion at the edge and on its internal electrical field distribution. Finally, the 3 level model was implemented into the simulation to study the behaviour of such detector under different level of irradiation.

[en] Elastic and inelastic scattering has been measured at Esub(lab) = 360 MeV and 1016 MeV for the ¹²C + ¹²C system, as well as elastic scattering for ¹³C + ²⁰⁸Pb at 390 MeV. Optical model analysis is reported and nuclear surface transparency effects are discussed, together with energy dependence of the nuclear potential. DWBA analysis of data on the 2⁺, 4.4 MeV state of ¹²C is reported, trends on the energy dependence of mean field excitations are deduced

[en] It is shown that a simplified Glauber approach using an experimental nucleon-nucleon forward amplitude and a Gaussian nucleus density reproduces fairly well both nucleus-nucleus reaction cross sections and elastic scattering differential cross sections over a broad energy range

No abstract available

[en] Full text: In this study we have determined the concentration of some impurities such as carbon, iron, copper, titanium, nickel of the flat product (polycrystalline silicon). These impurities generate a yield decrease in the photovoltaic components. The material (polycrystalline silicon) used in this work is manufactured by the Unit of Silicon Technology Development (UDTS Algiers, Algeria). The 80 kg ingot has been cutted into 16 briquettes in order to have plates (flat product) of 100 mm x 100 mm dimensions. Each briquette is divided into three parts top (T), middle (M) and bottom (B). For this purpose, the following instrumental analysis techniques have been employed: neutronic analysis ( neutronic activation analysis) and secondary ion mass spectrometry (SIMS). Masses of 80 mg are sampled and form of discs 18 mm in diameter, then exposed to a flux of neutron of 2.1012 neutron cm^-2 s^-1 during 15 min . The R= 3.1012 energetic profile of incidental flux is constituted of fast neutrons ( TH = 1013 ncm^-2 s^-1; E = 0.025 eV) ncm^-2 s^-1; E = 2 MeV), thermal neutrons ( epi = 7.1011 n cm^-2 s^-1; E and epithermal neutrons (> 4.9 eV), irradiation time 15 mn, after 20 mn of decrement, acquisitions of 300 s are carried out, the results are expressed by disintegration per second which does not exceed the 9000, 500 and 2600 Bq, respectively for copper, titanium and nickel. It is observed that the impurities concentrations in the medium are higher. The impurities in the bottom of the ingots originate from the crucible. The impurities in the top originate from impurities dissolved in the liquid silicon, which have segregated to the top layer of the ingot and after solidification diffuse. Silicon corresponds to a mixture of three isotopes ²⁸Si, ²⁹Si and ³⁰Si. These elements clearly appear on the mass spectrum (SIMS).The presence of iron and the one of nickel has been noticed. (author)

No abstract available

[en] Elastic and inelastic scattering have been measured at Esub(lab) = 360 MeV and 1016 MeV for the ¹²C + ¹²C system, as well as elastic scattering for ¹³C + ²⁰⁸Pb at 390 MeV. An optical-model analysis is reported and nuclear surface transparency effects are discussed, together with the energy dependence of the nuclear potential. A DWBA analysis of data on the 2⁺, 4.4 MeV state of ¹²C is reported and trends in the energy dependence of mean-field excitations are deduced. (orig.)