Potential common radiation problems for components and diagnostics in future magnetic and inertial confinement fusion devices

This work aims at identifying common potential problems that future fusion devices will encounter for both magnetic (MC) and inertial (IC) confinement approaches in order to promote joint efforts and to avoid duplication of research

Neutrino physics with the PTOLEMY project: active neutrino properties and the light sterile case

The PTOLEMY project aims to develop a scalable design for a Cosmic NeutrinoBackground (CNB) detector, the first of its kind and the only one conceivedthat can look directly at the image of the Universe encoded in neutrinobackground produced in the first second after the Big Bang. The scope of thework for the next three years is to complete the conceptual design of thisdetector and to validate with direct measurements that the non-neutrinobackgrounds are below the expected cosmological signal. In this paper wediscuss in details the theoretical aspects of the experiment and its physicsgoals. In particular, we mainly address three issues. First we discuss thesensitivity of PTOLEMY to the standard neutrino mass scale. We then study theperspectives of the experiment to detect the CNB via neutrino capture ontritium as a function of the neutrino mass scale and the energy resolution ofthe apparatus. Finally, we consider an extra sterile neutrino with mass in theeV range, coupled to the active states via oscillations, which has beenadvocated in view of neutrino oscillation anomalies. This extra state wouldcontribute to the tritium decay spectrum, and its properties, mass and mixingangle, could be studied by analyzing the features in the beta decay electronspectrum

Plasma etching to enhance the surface insulating stability of alumina for fusion applications

A significant increase in the surface electrical conductivity of alumina, considered one of the most promising insulating materials for numerous applications in fusion devices, has been observed during ion bombardment in vacuum due to oxygen loss by preferential sputtering. Although this is expected to cause serious limitations to insulating components functionality, recent studies showed it is possible to restore the damaged lattice by oxygen reincorporation during thermal treatments in air. These studies also revealed a correlation between conductivity and ion beam induced luminescence, which is being used to monitor surface electrical conductivity degradation and help qualify the post irradiation recovery. Work now carried out for Wesgo alumina considers oxygen implantation and plasma etching as additional methods to improve recovered layer depth and quality. Both conductivity and luminescence results indicate the potential use of plasma etching not only for damage recovery, but also as a pre-treatment to enhance material stability during irradiation

Cuarzo KU1 de alta resistencia a la radiación

Radiation induced optical absorption and radioluminescence impose important limitations on the use of any optical materials under ionizing radiation. Optical transmission of a type of high purity silica glass, KU1 quartz glass, has been studied under radiation (gamma 60Co and 1.8 Mev electrons). The results show that this material maintain their transmission properties, from 400 to 2600 nm under high levels of ionizing radiation and with atomic displacements, during long time. Also radioluminescence produced by electrons and radiation effect on laser damage in this material have been studied.<br><br>La absorción óptica inducida por radiación así como la emisión de luz (radioluminiscencia) imponen severas limitaciones en el uso de materiales ópticos dentro de un campo de radiación. Para un tipo de sílice de alta pureza, cuarzo KU1, se ha estudiado el efecto de la radiación (gamma 60Co y electrones de 1.8 Mev), en la transmisión óptica. Se ha visto que este material mantiene sus propiedades de transmisión óptica, entre 400 y 2600 nm, en altos niveles de radiación tanto puramente ionizante como con desplazamientos, durante largos periodos de tiempo. También se ha estudiado la radioluminiscencia producida con electrones y el efecto de la radiación en el daño producido por láser en este material

Are different species of Dinophysis selected by climatological conditions?

Dinophysis acuminata and D. acuta, the main agents of diarrhetic shellfish poisoning outbreaks in the Galician Rías Baixas, North-West Spain, appear segregated in time and/or space and exhibit considerable interannualvariability. To explore the specific requirements of the two species and the causes of their alternation in latesummer outbreaks, the meteorologically driven structure of the water column was examined in relation toDinophysis populations from monthly transects in Ría de Vigo and weekly sampling at a pilot station in Ría de Pontevedra during 2002 and 2003 — two years with contrasting meteorology. D. acuminata had a longergrowth season and reached higher concentrations in parallel with higher standing stocks of diatoms and dinoflagellates during 2002 compared with 2003. Its summer maxima were associated with thermohalinestratification and persistent northerly winds of daily mean velocities of 2.5–4.0m s–1. In contrast, during 2003, when the summer was very hot and the upwelling index was the lowest for the past 50 years, and the stratification was more intensively thermally driven, the latesummerpopulations of D. acuminata were replaced by those of D. acuta. The relationship between Dinophysis spp. and climatological conditions, as well as the more severe socio-economic impacts of 2003 relative to 2002,are discussed

Influence of upwelling and river runoff interaction on phytoplankton assemblages in a Middle Galician Ria and comparison with northern and southern rias (NW Iberian Peninsula)

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Trapping and thermal diffusion for energetic deuterium implanted into SiC

During ITER and DEMO reactor operation Li–Pb blanket flow channel inserts made from SiC will be exposed to both radiation and tritium. Absorption, desorption, and tritium diffusion are expected to occur and will strongly depend on the irradiation conditions; temperature, and neutron and gamma fluxes. Reaction bonded (RB) SiC samples were deuterium implanted at both room temperature and 450°C at different implantation energies and the corresponding TSD spectrum was obtained for each implantation energy. After implantation the samples were subjected to SIMS analysis. The TSD spectra obtained for all the samples implanted at different energies are very similar and characterized by a prominent deuterium desorption occurring at temperatures between 450 and 1000°C with a maximum that exhibits a clear trend to shift toward higher temperature as either implantation energy or implantation temperature increase. SIMS analysis before heating the deuterium implanted samples indicates that the implanted deuterium has a tendency to become bonded to Si rather than to C. The SIMS analysis shows that once heated up to 1000°C only part of the implanted deuterium was thermally released. The temperature shift observed when increasing the deuterium implantation energy and, hence, penetration, implies a deuterium diffusivity value at 700°C of about 8.5×10−17m2/s