ESTRUCTURA POBLACIONAL, ABUNDANCIA Y DISTRIBUCIÓN DE Pelagia noctiluca DURANTE LA ÉPOCA ESTIVAL EN EL MEDITERRÁNEO NOROESTE

El presente trabajo describe la población de la medusa Pelagia noctiluca en cuanto a su distribución geográfica, abundancia en número de individuos, distribución de frecuencias de tallas y su relación tallapeso, a lo largo de la plataforma continental del Mediterráneo español (entre la frontera con Francia y el Estrecho de Gibraltar). Además, se analizó la influencia de los parámetros ambientales temperatura y salinidad superficial en relación a su abundancia, mediante Modelos Aditivos Generalizados (GAM). Los datos analizados en este estudio se obtuvieron en las campañas MEDiterranean International Acoustic Survey (MEDIAS) realizadas en el mes de julio del año 2019 y 2020. Este estudio indicó que los ejemplares de tallas comprendidas entre 2 y 12 cm de P. noctiluca se encuentran en la plataforma continental durante los meses de verano presentando una mayor abundancia entre el delta del Llobregat y el cabo de Palos. Los resultados del modelo GAM indicaron que la salinidad influye, de manera significativa, en la abundancia y distribución de esta especie en esta zona. Una de las fortalezas de este estudio es la amplia cobertura espacial analizada, en comparación con trabajos anteriormente publicados. En futuras líneas de investigación complementarias podría considerarse el estudio de la predación de especies pelágicas capturadas durante la campaña MEDIAS sobre la Pelagia noctiluca

operation and performance of the icarus t600 cryogenic plant at gran sasso underground laboratory

ICARUS T600 liquid argon time projection chamber is the first large mass electronic detector of a new generation able to combine the imaging capabilities of the old bubble chambers with the excellent calorimetric energy measurement. After the three months demonstration run on surface in Pavia during 2001, the T600 cryogenic plant was significantly revised, in terms of reliability and safety, in view of its long-term operation in an underground environment. The T600 detector was activated in Hall B of the INFN Gran Sasso Laboratory during Spring 2010, where it was operated without interruption for about three years, taking data exposed to the CERN to Gran Sasso long baseline neutrino beam and cosmic rays. In this paper the T600 cryogenic plant is described in detail together with the commissioning procedures that lead to the successful operation of the detector shortly after the end of the filling with liquid Argon. Overall plant performance and stability during the long-term underground operation are discussed. Finally, the decommissioning procedures, carried out about six months after the end of the CNGS neutrino beam operation, are reported

ICARUS: An Innovative Large LAR Detector for Neutrino Physics

ICARUS is an international project that foresees the installation of very large LAr detectors inside the Gran Sasso underground laboratory in order to be sensitive to rare phenomena of particle physics. The detection technique is based on the collection of electrons produced by particle interactions in LAr by a matrix of thousands of thin wires. At the moment the project foresees the installation of a 600,000‐kg vessel (T600). The total amount of LAr can be expanded in a modular way to masses of the order of 106 kg. The T600 houses two identical 300,000‐kg Ar sub‐cryostats that are aluminum boxes about 20‐m long, 4‐m high and 4‐m wide. Safety requirements for the underground installation have led to a unique design for the vessels to prevent LAr spillages even in the case of inner cryostat failure. Electrons must drift over meters requiring the development of special gas and liquid Ar purification units to provide an extremely high LAr purity (better then 0.1 ppb). The cooling system has been designed to assure a high thermal uniformity in the detector volume (less than 1‐K differential). The cryogenic system associated with the final ICARUS configuration is based on three N2 refrigerators, three 30‐m3 tanks and pump driven two‐phase N2 forced‐flow cooling of the various sub‐systems. The T600 was successfully tested in Pavia in 2001 and it is now under installation in Gran Sasso for final operation. The future mass expansion strategy is under investigation

A high magnetic field and very low temperature cryomagnet for neutron scattering experiments

A cryomagnetic system is described in which the main components are a cryostat providing variable temperatures and a superconducting magnet The cryostat enables the magnet to operate either at 4.2 K or 2.17 K and the sample temperature to be varied from 1.5 K to 300 K. The magnet is a split coil providing a vertical magnetic field of 8.7 T at 4.2 K and 10 T at 2.17 K. A 3He- 4He dilution refrigerator insert can be used to reach T = 50 mK. A few significative experimental results are presented concerning UAs, CeSb, CeB6 and TMMC.Nous décrivons un système cryomagnétique qui comprend principalement un cryostat permettant d'obtenir des températures variables et un aimant supraconducteur. Le cryostat permet d'utiliser l'aimant supraconducteur soit à 4,2 K soit à 2,17 K et d'obtenir des températures sur l'échantillon comprises entre 1,5 K et 300 K. L'aimant est réalisé par deux bobines en position d'Helmotz qui fournissent un champ vertical de 8,7 T à 4,2 K et de 10 T à 2,17 K. Un anticryostat équipé d'un réfrigérateur à dilution 3He-4He peut être installé qui permet d'atteindre 50 mK. Quelques résultats significatifs sont rapportés concernant UAs, CeSb, CeB6 et TMMC

Comparing neutron and X-ray images from NIF implosions

Directly laser driven and X-radiation driven DT filled capsules differ in the relationship between neutron and X-ray images. Shot N110217, a directly driven DT-filled glass micro-balloon provided the first neutron images at the National Ignition Facility. As seen in implosions on the Omega laser, the neutron image can be enclosed inside time integrated X-ray images. HYDRA simulations show the X-ray image is dominated by emission from the hot glass shell while the neutron image arises from the DT fuel it encloses. In the absence of mix or jetting, X-ray images of a cryogenically layered THD fuel capsule should be dominated by emission from the hydrogen rather than the cooler plastic shell that is separated from the hot core by cold DT fuel. This cool, dense DT, invisible in X-ray emission, shows itself by scattering hot core neutrons. Germanium X-ray emission spectra and Ross pair filtered X-ray energy resolved images suggest that germanium doped plastic emits in the torus shaped hot spot, probably reducing the neutron yield