THI safety system

International audienceFor several years, GANIL has been allowed to reach a maximum beam power of six kilowatts (400W in normal mode) thanks to the THI system (High Intensity Transport System). Three modes of running are necessary to accelerate a THI beam ("Injector" mode, "tuning" mode and "surveillance" mode). The "surveillance" mode requires a safety system to protect equipment against beam losses. Inside cyclotrons, diagnostics measure beam-loss currents at the injection and extraction devices. Along beam lines, diaphragms measure beam-loss currents at the input and output of dipoles. Current transformers are used for beam transmission measurements through beam lines and the cyclotrons. The safety system controls beam losses and quickly cuts the beam with a chopper if losses exceed thresholds. These thresholds can be seen and changed by software

A new access control unit for GANIL and SPIRAL 2

International audienceFor the GANIL safety revaluation and the new project of accelerator SPIRAL 2, it was decided to replace theexisting access control system for radiological controlled areas. These areas are all cyclotron rooms and experimental areas. The existing system is centralized around VME cards. Updating is becoming very problematic. The new UGA (access control unit) will becomposed of a pair of PLC to ensure the safety of each room. It will be supplemented by a system UGB (radiological control unit) that will assure the radiological monitoring of the area concerned

Recent developments for beam intensity increase operation

International audienceThe aim of the beam intensity increase operation (THI project) is to multiply the present intensities for lightest ions by a factor of fifteen in order to reach maximum power of six kilowatts [1]. The main objective is the production of large amounts of rare isotopes, either with SISSI (device intended for producing radioactive beams), or with SPIRAL (production and acceleration of radioactive ion beams). As part of this THI project, new developments have been required such as spiral scanners, for beanl profile measurements, and safety system to protect equipments against beam losses. Other developments are being carried on to improve the high intensity beam operation

Apport de la matière organique dans l'étude de la dynamique sédimentaire lacustre en zone sahélienne (exemples de deux complexes limniques, SW Niger)

International audienceLe remplissage sédimentaire des mares de Bangou-Bi et de Tankalawal (SW Niger) a fait l'objet d'une étude de son contenu organique qui fournit des informations sur l'origine et les conditions de dépôt du matériel sédimentaire. Deux carottes mesurant respectivement 140 cm (carotte BB2) et 60 cm (carotte TK1) ont été étudiées. Les échantillons ont été soumis à une pyrolyse Rock-Eval 6 renseignant sur la géochimie globale de la Matière Organique (MO) et le signal S2 de la pyrolyse a été exploité afin de mieux préciser la nature de ces MO. Le niveau argilo-limoneux de la carotte BB2 contient une MO aquatique et terrestre dont la composition en composés hydrocarbonés se répartit entre les biopolymères (F1+F2), et les géopolymères matures (F3) et immatures (F4). Cette MO serait déposée dans un environnement calme. En revanche le niveau inférieur sableux renferme une MO terrestre très altérée et enrichie en géopolymères matures qui serait amenée par des pulses détritiques grossiers (colluvionnement) issus du bassin versant. Les valeurs des paramètres géochimiques et leur évolution avec la profondeur indiquent que la MO de la carotte TK1 est aquatique et a enregistré une dégradation en milieu anoxique. Cette MO contenant majoritairement des géopolymères matures (F4) riches en lipides se révèle étonnamment plus résistante face à l'altération que celle présente dans la carotte BB2

Evaluation intégrée des mesures agro-environnementales territorialisées à enjeu "qualité des eaux" sur la période 2007 à 2011 : le projet MAEVEAU

The MAEVEAU project has developed an approach for an integrated assessment of effectiveness of regionalized Agro-Environmental Measures (MAET) intended to preserve water quality in relation to pesticides. This approach investigates the concept of efficiency through a triple analysis: the impact (net effects), the environmental cost-effectiveness and the role of organizational factors in the contracting process. The impact is assessed by a quasi-experimental approach by counterfactuals and examines adaptation of the matching method to the regionalized MAET. Cost-effectiveness analysis is based on integrated modeling spatially distributed coupling the agro-hydrological SWAT model, pesticides pressure indicators and a bio-economic model optimizing gross margin. The effectiveness of organizational factors focuses on transaction costs, the role of collective action and preferences for alternative contracts.La recherche conduite dans le projet MAEVEAU a développé une démarche d'évaluation intégrée de l'efficacité des Mesures Agro-Environnementales Territorialisées (MAET) à enjeu préservation de la qualité de l'eau vis-à-vis des pesticides sur la période 2007 à 2011. La question scientifique traite le concept d'efficacité de la politique en s'appuyant sur une triangulation des approches: une évaluation de l'impact (c'est-à-dire des effets propres de la politique), une évaluation coût-efficacité environnementale et une évaluation du rôle des facteurs organisationnels dans le processus d'adhésion. L'impact est évalué par une approche quasi-expérimentale par contrefactuel et questionne l'adaptation de la méthode du matching à la territorialisation des MAET. L'analyse coût-efficacité s'appuie sur une modélisation intégrée spatialisée couplant modèle agro-hydrologique, indicateurs pesticides spatialisés et optimisation économique des marges brutes. L'efficacité des facteurs organisationnels s'est intéressée aux coûts de transaction, au rôle de l'action collective et aux préférences pour des contrats alternatifs

Working With the Tangible: Radiation, A Twenty-First Century Interpretation

The intangible means of expression was a topic of investigation across various disciplines when Michael Chekhov was developing his pedagogic practice. In the world of science, Harold Saxton Burr and Albert Szent-Gyorgi, were examining the body as a conductor of energy. Their research was relevant to Chekhov's approach regarding how the actor communicates with internal and external stimulus. This article begins with an analysis of Chekhov's theories on Radiation, it moves on to offer insights into science and energy work with reference to cell Biologist James Oschman and his concept of ‘the living matrix’ and Mae Wan Ho's critique of quantum cohesion. Examples of praxis demonstrate that contemporary science and body work can provide a greater understanding of how Radiation and the organisation of energy can enhance performance

Dispersion of Ordered Stripe Phases in the Cuprates

A phase separation model is presented for the stripe phase of the cuprates, which allows the doping dependence of the photoemission spectra to be calculated. The idealized limit of a well-ordered array of magnetic and charged stripes is analyzed, including effects of long-range Coulomb repulsion. Remarkably, down to the limit of two-cell wide stripes, the dispersion can be interpreted as essentially a superposition of the two end-phase dispersions, with superposed minigaps associated with the lattice periodicity. The largest minigap falls near the Fermi level; it can be enhanced by proximity to a (bulk) Van Hove singularity. The calculated spectra are dominated by two features -- this charge stripe minigap plus the magnetic stripe Hubbard gap. There is a strong correlation between these two features and the experimental photoemission results of a two-peak dispersion in La$_{2-x}$Sr$_x$CuO$_4$, and the peak-dip-hump spectra in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$. The differences are suggestive of the role of increasing stripe fluctuations. The 1/8 anomaly is associated with a quantum critical point, here expressed as a percolation-like crossover. A model is proposed for the limiting minority magnetic phase as an isolated two-leg ladder.Comment: 24 pages, 26 PS figure