No abstract available

[en] The term 'technical record in radiotherapy' is used to describe collected information relative to treatment using radiation. The subject of this session of the chapter of Radiotherapy of the Societe Francaise de Radiologie was the intrinsic functions of this record and its extrinsic limitations. The extreme diversity of the current state of the record is a known fact. A majority of participants express the desire for uniformisation of the collection of data or even, as a second stage, to have a common record. A library of technical records was set up under the responsibility of the Centre Georges-Francois Leclerc at Dijon. One broad conclusion was seen to emerge: the creation of a minimum common record including essential information to which could be added the more specific data of each radiotherapist and at each time of use. Prior agreement will be necessary with regard to the standardisation of apparatus and the expression of the dose

[en] In photovoltaic industry, contacts fabrication is an important step for solar cell efficiency improvement. In order to reduce the cost of the device, the metallizations are realized by screen-printing a paste. In this work, we have analyzed large area industrial solar cells with pn⁺ junction, SiO₂ passivation layer and TiO₂ antireflection coating (ARC) on front side. During the process, front contacts are screen-printed after TiO₂ ARC deposition. The metallization paste is composed of a glass powder, an active metal (Ag for front paste and Ag/Al for rear paste) and a binding agent. Its deposition is followed by a rapid firing step at high temperature (firing through the oxide layers) and an annealing at lower temperature under reducing ambient. The aim of this study is to understand chemical and metallurgical mechanisms that occur in front and backside metallizations during heat treatments necessary for contacts formation. Cross-section samples are realized by the tripod method. Observations are realized with a 200 kV field effect gun-transmission electron microscope (TEM) associated to an EDS analysis. A software allows to pilot the beam, scanning along a surface or a line to obtain, respectively, an X-ray cartography or concentration profiles by elements. The main result of this analysis is that front contact ohmicity is not realized by the silver active metal of the paste but by metallic species coming from glass oxides

[en] We study a class of type I string models with supersymmetry broken on the world-volume of some D-branes and vanishing tree-level potential. Despite the non-supersymmetric spectrum, supersymmetry is non-linearly realized on these D-branes, while it is spontaneously broken in the bulk by Scherk-Schwarz boundary conditions. These models can easily accommodate 3-branes with interesting gauge groups and chiral fermions. We also study the effective field theory and in particular we compute the four-fermion couplings of the localized goldstino with the matter fermions on the brane

No abstract available

[en] A study of electrically inactive defects has been performed on CdTe single crystals by two different experimental techniques: the low temperature thermal conductivity measurement -it has been used as a tool to study crystal defects, such as clusters, stacking faults or point defects-; the X-ray topographie -it completes the first method in showing large aggregates (resolution of 1μm) dislocation arrays or structural defects-. The following observations regarding the experiments are worth noting. CdTe crystals (undoped, Cl or In doped) have been grown by melting zone or THM. Microprecipitates are found in all CdTe crystals. The concentration varies from 10¹⁴ up to 10¹⁵cm^-3 and the mean diameter reaches 100A or more. This concentration is independent on the doping level and on the crystal growth process. The presence of such a precipitation is probably associated with the chemical and thermal growth conditions of the crystals. The K(T) curves fit by the Callaway phenomenological model indicates a point defect concentration of about 10¹⁸cm^-3. The isotopic mass deviation introduces only a concentration of 7x10¹⁷cm^-3. The excess is ascribed to several origins such as nonstoichiometry in CdTe, doping, chemical impurities or Vsub(cd). In X-ray topography large precipitates appear only in crystals not intentionally doped and melting zone purified or in CdTe:Cl. No correlation is found between large and micro precipitates. Dislocations with atmosphere appear also with a low concentration of about 10⁴cm^-2

No abstract available

No abstract available

[en] Thin film single crystal silicon on foreign substrate is an attractive way to realize cheap and efficient photovoltaic devices. In this paper we will compare epitaxial growth of silicon thin film on double porous sacrificial layers obtained by liquid or vapor phase epitaxy (LPE or VPE). Porous silicon is formed by electrochemical anodisation of monocrystalline silicon in a HF/ethanol solution. VPE is achieved in an atmospheric pressure chemical vapor deposition (APCVD) reactor under H₂ atmosphere. Growth rate is in between 0.5-3 μm/min. LPE is realised in a graphite sliding boat using indium or tin as solvent. Growth rate is in the range 0.1-1 μm/min depending on the temperature, the cooling rate and the solvent. We discuss the substrate orientation, temperature, growth rate, layer homogeneity and electrical properties of the epilayers for both growing techniques. Diffusion length and mobility are measured respectively with LBIC and Hall effect technique. The values obtained for p-type (μ>100 V/cm²/s and L_n>100 μm) allows the realisation of solar cell using interdigitated technology on the top of this layer, which is detached and transferred onto mullite substrate

[en] We study mediation of supersymmetry breaking in the bulk, in models with primordial supersymmetry breaking on D-branes at the string scale, in the TeV region. We compute the gravitino and scalar masses up to one-loop level, as well as the radion coupling to matter. We find that the latter mediates a model independent force at submillimeter distances that can be tested in micro-gravity experiments for any dimensionality of the bulk. In the case of two large dimensions, our type I string framework provides an example which allows to stabilize the radion potential and determine the desired hierarchy between the string and Planck scales