Measurement of the neutron capture cross section of the fissile isotope 235U with the CERN n_TOF Total Absorption Calorimeter and a fission tagging based on micromegas detectors

Actual and future nuclear technologies require more accurate nuclear data on the (n, gamma) cross sections and -ratios of fissile isotopes. Their measurement presents several difficulties, mainly related to the strong fission gamma-ray background competing with the weaker gamma-ray cascades used as the experimental signature of the (n,gamma) process. A specific setup has been used at the CERN n_TOF facility in 2012 for the measurement of the (n,gamma) cross section and alpha-ratios of fissile isotopes and used for the case of the 235U isotope. The setup consists in a set of micromegas fission detectors surrounding 235U samples and placed inside the segmented BaF2 Total Absorption Calorimeter.Postprint (published version

Trastorno por déficit de atención e hiperactividad dual en niños y adolescentes internados en un centro para el tratamiento de adicciones

Introducción: El trastorno por déficit de atención e hiperactividad es el trastorno psiquiátrico más frecuente en la edad escolar y múltiples estudios han evidenciado que es un factor de riesgo independiente para desarrollar abuso o dependencia de sustancias. El objetivo principal de este trabajo es determinar la frecuencia de este trastorno y otros trastornos externalizantes en niños y adolescentes internados en un centro de referencia, así como el impacto de estas patologías en la escolarización, inicio precoz del consumo de sustancias, caracterización de las conductas adictivas y perfil de los pacientes. Sujetos y métodos: Se analizaron las historias clínicas de la totalidad de niños y adolescentes internados en un centro de referencia durante los meses de junio y julio de 2013, todos ellos con el diagnóstico de trastorno por uso de sustancias. Se realizaron entrevistas estructuradas para los diagnósticos de déficit de atención e hiperactividad y otros trastornos externalizantes. Resultados: Se determinó la presencia de comorbilidad con déficit de atención e hiperactividad en el 40% de los pacientes y de comorbilidad con trastorno disocial en 95% de los pacientes. Los pacientes con déficit de atención e hiperactividad presentaron mayores dificultades en la escolarización y en el inicio precoz en el uso de sustancias. Conclusión: el trastorno por déficit de atención e hiperactividad es frecuentemente minimizado en sus síntomas y sobre todo en las posibles consecuencias negativas para el paciente; si su diagnóstico no se realiza a tiempo, no será posible un buen abordaje terapéutico del niño y adolescente

Large magnetoelectric coupling in multiferroic oxide heterostructures assembled via epitaxial lift-off.

Epitaxial films may be released from growth substrates and transferred to structurally and chemically incompatible substrates, but epitaxial films of transition metal perovskite oxides have not been transferred to electroactive substrates for voltage control of their myriad functional properties. Here we demonstrate good strain transmission at the incoherent interface between a strain-released film of epitaxially grown ferromagnetic La0.7Sr0.3MnO3 and an electroactive substrate of ferroelectric 0.68Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 in a different crystallographic orientation. Our strain mediated magnetoelectric coupling compares well with respect to epitaxial heterostructures, where the epitaxy responsible for strong coupling can degrade film magnetization via strain and dislocations. Moreover, the electrical switching of magnetic anisotropy is repeatable and non volatile. High resolution magnetic vector maps reveal that micromagnetic behaviour is governed by electrically controlled strain and film microstructure. Our demonstration should permit the physical/chemical properties in strain-released epitaxial oxide films to be controlled using electroactive substrates to impart strain via non epitaxial interfaces.Beatriu de Pinós postdoctoral fellowship (2014 BP-A 00079) from the Catalan government via the Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR); Ministry of Science and Higher Education of Russian Federation, goszadanie no. 2019-1246; the Royal Society; EPSRC (Grant EP/P009050/1, EP/M010619/1 and the NoWNano DTC); European Research Council (ERC) (ERC-2016-STG-EvoluTEM-715502 and ERC Synergy HETERO2D); “la Caixa” Foundation (ID 100010434)

Present Status and Future Programs of the n_TOF Experiment

This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License 3.0, which permits unrestricted use, distribution, and reproduction in any noncommercial medium, provided the original work is properly citedThe neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.The most relevant measurements performed up to now and foreseen for the future will be presented in this contribution. The overall efficiency of the experimental program and the range of possible measurements achievable with the construction of a second experimental area (EAR-2), vertically located 20 m on top of the n_TOF spallation target, might offer a substantial improvement in measurement sensitivities. A feasibility study of the possible realisation of the installation extension will be also presented

Neutron cross-sections for advanced nuclear systems : The n-TOF project at CERN

© Owned by the authors, published by EDP Sciences, 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n-TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.Peer reviewedFinal Published versio

238U(n, γ) reaction cross section measurement with C 6D6 detectors at the n-TOF CERN facility

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe radiative capture cross section of 238U is very important for the developing of new reactor technologies and the safety of existing ones. Here the preliminary results of the 238U(n,γ) cross section measurement performed at n-TOF with C6D6 scintillation detectors are presented, paying particular attention to data reduction and background subtraction.Peer reviewe

Ni-62(n,gamma) and Ni-63(n,gamma) cross sections measured at the n_TOF facility at CERN

The cross section of the Ni-62(n,gamma) reaction was measured with the time-of-flight technique at the neutron time-of-flight facility n_TOF at CERN. Capture kernels of 42 resonances were analyzed up to 200 keV neutron energy and Maxwellian averaged cross sections (MACS) from kT = 5-100 keV were calculated. With a total uncertainty of 4.5%, the stellar cross section is in excellent agreement with the the KADoNiS compilation at kT = 30 keV, while being systematically lower up to a factor of 1.6 at higher stellar temperatures. The cross section of the Ni-63(n,gamma) reaction was measured for the first time at n_TOF. We determined unresolved cross sections from 10 to 270 keV with a systematic uncertainty of 17%. These results provide fundamental constraints on s-process production of heavier species, especially the production of Cu in massive stars, which serve as the dominant source of Cu in the solar system.Peer reviewedFinal Accepted Versio

The 33S(n,α)30Si cross section measurement at n-TOF-EAR2 (CERN) : From 0.01 eV to the resonance region

The 33S(n,α)30Si cross section measurement, using 10B(n,α) as reference, at the n-TOF Experimental Area 2 (EAR2) facility at CERN is presented. Data from 0.01 eV to 100 keV are provided and, for the first time, the cross section is measured in the range from 0.01 eV to 10 keV. These data may be used for a future evaluation of the cross section because present evaluations exhibit large discrepancies. The 33S(n,α)30Si reaction is of interest in medical physics because of its possible use as a cooperative target to boron in Neutron Capture Therapy (NCT)