Status report of the n_TOF facility after the 2nd CERN long shutdown period

During the second long shutdown period of the CERN accelerator complex (LS2, 2019-2021), several upgrade activities took place at the n_TOF facility. The most important have been the replacement of the spallation target with a next generation nitrogen-cooled lead target. Additionally, a new experimental area, at a very short distance from the target assembly (the NEAR Station) was established. In this paper, the core commissioning actions of the new installations are described. The improvement in the n_TOF infrastructure was accompanied by several detector development projects. All these upgrade actions are discussed, focusing mostly on the future perspectives of the n_TOF facility. Furthermore, some indicative current and future measurements are briefly reported

Cambio tecnológico y cambio organizacional. La organización en red

El artículo postula que la revolución tecnológica de la información esta trastocando todos los dominios de la realidad social, al igual que las otras dos grandes revoluciones tecnológicas –la del vapor y la de la electricidad- que marcaron la historia contemporánea. Somos actualmente testigos de la emergencia de una nueva sociedad civil que desborda las fronteras de los Estados-Nación y funciona en unidad de tiempo real y a escala global. El texto recorre los rasgos principales del Análisis de Redes Sociales, concebido como un enfoque analítico promisorio que nos permite aprehender la lógica organizativa emergente.L’article affirme que la révolution technologique de l’information affecte tous les domaines de la réalité sociale, de même que les deux autres grandes révolutions technologiques – celle de la vapeur et celle de l’électricité – qui marquèrent l’histoire contemporaine. Nous sommes aujourd’hui témoins de l’émergence d’une nouvelle société civile qui déborde les frontières de l’Etat-nation et fonctionne en unité de temps réel et à l’échelle globale. Ce texte explore les traits principaux de l’Analyse des Réseaux Sociaux, conçue comme une approche analytique promissoire qui nous permet d’appréhender la logique organisationnelle émergente.The article claims that the information technological revolution is overturning all domains of social reality, likewise the other two great technological revolutions –those of steam and of electricity- that marked contemporary history. We are currently witnessing the emergence of a new civil society that goes beyond the borders of nation-states and operates in real-time unit and globally. The text covers the main features of Social Network Analysis, designed as a promising analytical approach that allows us to grasp the emerging organizational logic

Cambio tecnológico y cambio organizacional. La organización en red

El artículo postula que la revolución tecnológica de la información esta trastocando todos los dominios de la realidad social, al igual que las otras dos grandes revoluciones tecnológicas –la del vapor y la de la electricidad- que marcaron la historia contemporánea. Somos actualmente testigos de la emergencia de una nueva sociedad civil que desborda las fronteras de los Estados-Nación y funciona en unidad de tiempo real y a escala global. El texto recorre los rasgos principales del Análisis de Redes Sociales, concebido como un enfoque analítico promisorio que nos permite aprehender la lógica organizativa emergente.L’article affirme que la révolution technologique de l’information affecte tous les domaines de la réalité sociale, de même que les deux autres grandes révolutions technologiques – celle de la vapeur et celle de l’électricité – qui marquèrent l’histoire contemporaine. Nous sommes aujourd’hui témoins de l’émergence d’une nouvelle société civile qui déborde les frontières de l’Etat-nation et fonctionne en unité de temps réel et à l’échelle globale. Ce texte explore les traits principaux de l’Analyse des Réseaux Sociaux, conçue comme une approche analytique promissoire qui nous permet d’appréhender la logique organisationnelle émergente.The article claims that the information technological revolution is overturning all domains of social reality, likewise the other two great technological revolutions –those of steam and of electricity- that marked contemporary history. We are currently witnessing the emergence of a new civil society that goes beyond the borders of nation-states and operates in real-time unit and globally. The text covers the main features of Social Network Analysis, designed as a promising analytical approach that allows us to grasp the emerging organizational logic

Internet y Comunidad: Una aproximación desde el enfoque del estudio de redes personales

El propósito de este artículo es esencialmente aportar a la renovación metodológica en el campo de la investigación social. En concreto, se buscar presentar y fundamentar sobre las potencialidades del uso del estudio de las redes personales a partir de la aplicación de conceptos, métodos y técnicas propios del enfoque del Análisis de Redes Sociales (ARS). El método será desafiado como herramienta para abordar uno de los temas recurrentes en los debates sociológicos, la contigüidad espacial para la construcción de la comunidad. En concreto, nuestro soporte contextual será el aprendizaje obtenido a partir de la aplicación de este método en la investigación realizada para evaluar el impacto de Internet en la formación de capital individual y colectivo en un conjunto seleccionado de localidades de la Patagonia chilena caracterizadas por sus niveles críticos de aislamiento.The aim of this paper is to make a contribution to the renewal of social research. Specifically, we seek to provide a state-of-the-art about the personal networks studies from the application of concepts, methods and techniques of Social Network Analysis (SNA). The method will be challenged as tool to approach one of the most relevant issues of modern sociology, the spatial conditions for community building. The framework support will be the learning obtained from the application of this method in the research undertook to evaluate the impact of Internet in the individual and collective social capital formation in a selected group of Chilean Patagonia´s locality, characterized by its critic levels of isolation.O objetivo deste artigo é, essencialmente, contribuir para a renovação metodológica no campo da pesquisa social. Concretamente, se procura apresentar fundamentar o potencial do uso do estudo das redes pessoais a partir da aplicação de conceitos, métodos e técnicas próprios do enfoque da Análise de Redes Sociais (ARS). O método será desafiado como uma ferramenta para abordar um dos temas recorrentes em debates sociológicos, a contiguidade espacial para a construção da comunidade. Especificamente, o nosso apoio contextual será a aprendizagem obtida a partir da aplicação deste método na pesquisa realizada para avaliar o impacto da Internet sobre a formação de capital individual e coletivo em um conjunto selecionado de localizações na Patagônia chilena, caracterizada por seus níveis críticos de isolamento

De Internet, la sociedad red y la política

Frente a la naturaleza revolucionaria de internet, capaz de funcionar en unidad de tiempo real y a escala global, el autor se sitúa entre los "Cyberoptimistas" y los "Cyberpesimistas", para postular una actitud más reflexiva. En el artículo aborda la compleja interacción entre el internet y los cambios en la gobernabilidad de las sociedades, desarrollando temas como los de  autogobierno la disminución de mecanismos de coerción estatal y la importancia de avanzar hacia la plena incorporación de las tecnologías digitales a la gobernabilidad de los países.Fa ce à la nature révolutionnaire d’internet, capable de fonctionner en unité de temps réel à l’échelle globale, l’auteur se place entre les “Cyberoptimistes” et les “Cyberpessimistes”, pour défendre une posture plus réflexive. Cet article aborde la complexe interaction entre internet et les changements dans la gouvernabilité des sociétés, développant des thèmes tels que l’autogouvernement, la diminution des mécanismes de coercition étatique et l’importance des avancées vers la pleine incorporation des technologies numériques à la gouvernabilité des pays.Facing the revolutionary nature of Internet, capable of operating in real-time unit and globally, the author installs himself between the "Cyberoptimists" and the "Cyberpesimists" to postulate a more thoughtful attitude. The article discusses the complex interaction between Internet and changes in governance of societies by developing self-government issues such as declining state enforcement mechanisms and the importance of moving towards full integration of digital technologies to countries governance

Relation between temperature and the beginning of peel color change in grapefruit (Citrus paradisi Macf.)

The grapefruit varieties Marsh (white-fleshed) and Redblush (pink-fleshed) are the most widely cultivated varieties in the world. In this work we attempt to determine the temperature below which degreening begins in these two varieties of grapefruit, first studying the influence of radiation on the colorimetric coordinates and then the influence of minimum temperatures on the change from green to yellow, based on the data gathered during the 2005/6, 2006/7, 2010/11 and 2011/12 growing seasons. The results show that net radiation alone does not explain when degreening begins, but that the process depends on the mean of the minimum temperatures for the 14 days preceding the sampling being below 14 °C. Finally, we discuss the relationships between coordinate a, and each of the following variables: maturity index (MI), °Brix, and percentage of acidity, concluding that the indices show that grapefruit are mature at the beginning of autumn when the peel is still green. Therefore, these indices are not related with natural degreening, which occurs in autumn. This knowledge will help predict the color that fruit will reach according to the temperatures of a given geographical area and whether or not degreening chambers will have to be used, with the additional costs that this implies

Preliminary results on the 233U capture cross section and alpha ratio measured at n_TOF (CERN) with the fission tagging technique

233U is of key importance among the fissile nuclei in the Th-U fuel cycle. A particularity of 233U is its small neutron capture cross-section, which is on average about one order of magnitude lower than the fission cross-section. The accuracy in the measurement of the 233U capture cross-section depends crucially on an efficient capture-fission discrimination, thus a combined set-up of fission and γ-detectors is needed. A measurement of the 233U capture cross-section and capture-to-fission ratio was performed at the CERN n_TOF facility. The Total Absorption Calorimeter (TAC) of n_TOF was employed as γ-detector coupled with a novel compact ionization chamber as fission detector. A brief description of the experimental set-up will be given, and essential parts of the analysis procedure as well as the preliminary response of the set-up to capture are presented and discussed

The Stellar 72Ge(n, γ) Cross Section for weak s-process: A First Measurement at n_TOF

In line with the principles that apply to scientific publishing and the CERN policy in matters of scientific publications, the n_TOF Collaboration recognises the work of V. Furman and P. Sedyshev (JINR, Russia), who have contributed to the experiment used to obtain the results described in this paper. This work was supported by the European Research Council ERC-2015-STG Nr. 677497, the Austrian Science Fund FWF (J 3503), the Science and Technology Facilities Council UK (ST/M006085/1), the Adolf Messer Foundation, the Croatian Science Foundation under the project 8570, the MSMT of the Czech Republic, the Charles University UNCE/SCI/013 project and by the funding agencies of the participating institutes.The slow neutron capture process (s-process) is responsible for producing about half of the elemental abundances heavier than iron in the universe. Neutron capture cross sections on stable isotopes are a key nuclear physics input for s-process studies. The Ge-72(n, gamma) Maxwellian-Averaged Cross Section (MACS) has an important influence on the production of isotopes between Ge and Zr in the weak s-process in massive stars and so far only theoretical estimations are available. An experiment was carried out at the neutron time-of-flight facility n_TOF at CERN to measure the Ge-72(n, gamma) reaction for the first time at stellar neutron energies. The capture measurement was performed using an enriched (GeO2)-Ge-72 sample at a flight path length of 184 m, which provided high neutron energy resolution. The prompt gamma rays produced after neutron capture were detected with a set of liquid scintillation detectors (C6D6). The neutron capture yield is derived from the counting spectra taking into account the neutron flux and the gamma-ray detection efficiency using the Pulse Height Weighting Technique. Over 70 new neutron resonances were identified, providing an improved resolved reaction cross section to calculate experimental MACS values for the first time. The experiment, data analysis and the new MACS results will be presented including their impact on stellar nucleosynthesis, which was investigated using the post-processing nucleosynthesis code mppnp for a 25 solar mass model.European Research Council (ERC) Spanish Government 677497Austrian Science Fund (FWF) J 3503UK Research & Innovation (UKRI) Science & Technology Facilities Council (STFC) ST/M006085/1Adolf Messer FoundationCroatian Science Foundation 8570Ministry of Education, Youth & Sports - Czech RepublicCharles University UNCE/SCI/01

High accuracy, high resolution U-235(n,f) cross section from n_TOF (CERN) from 18 meV to 10 keV

The 235U(n,f) cross section was measured in a wide energy range (18 meV–170 keV) at the n_TOF facility at CERN, relative to 6Li(n,t) and 10B(n,α) standard reactions, with high resolution and accuracy, with a setup based on a stack of six samples and six silicon detectors placed in the neutron beam. In this paper we report on the results in the region between 18 meV and 10 keV neutron energy. A resonance analysis has been performed up to 200 eV, with the code SAMMY. The resulting fission kernels are compared with the ones extracted on the basis of the resonance parameters of the most recent major evaluated data libraries.Acomparison of the n_TOF datawith the evaluated cross sections is also performed from thermal to 10 keV neutron energy for the energy-averaged cross section in energy groups of suitably chosen width. A good agreement, within 0.5%, is found on average between the new results and the latest evaluated data files ENDF/B-VIII.0 and JEFF-3.3, as well as with respect to the broad group average fission cross section established in the framework of the standard working group of IAEA (the so-called reference file). However, some discrepancies, of up to 4%, are still present in some specific energy regions. The newdataset here presented, characterized by a unique combination of high resolution and accuracy, low background and wide energy range, can help to improve the evaluations from the Resolved Resonance Region up to 10 keV, also reducing the uncertainties that affect this region.CERN (European Organization for Nuclear Research

A desorption model for the code SOLIDUSS and its experimental benchmarking

Acknowledgements The experiments reported in this document could be carried out thanks to the assistance of numerous colleagues at CERN. In particular, the authors would like to express their gratitude to Guilherme Correia, Karl Johnston, Juliana Schell, Sebastian Rothe, Jochen Ballof, Thierry Stora, Joachim Vollaire, Reiner Geyer, Yann Pira, Lucie Vitkova, Alexandre Dorsival, Nabil Menaa, Aurore Boscher, Giuseppe Prete, Renaud Charousset and Miranda Van Stenis.The code SOLIDUSS is a Monte Carlo based solid-state diffusion software for radiation protection. It was developed to accurately estimate the amount of radionuclides that could escape activated material affected by an accidental fire. A desorption model based on the computation of the desorption probability of those radionuclides reaching the surface of an object was introduced to upgrade the software, proven to be a significant improvement with respect to earlier stages of the code. A set of experiments was performed at CERN to estimate the out-diffusion of radionuclides from activated materials typically used in accelerator environments when exposed to high temperatures. In particular, a 49.3 µm thick Cu foil containing 60Co and a 94 µm thick Al foil with 22Na were exposed to approximately 1000 °C and 600 °C respectively for different time periods. Out-diffusion fractions of 1.5 5.5% for 60Co after 5 h and 22.5 3.1% for 22Na after 4 h were obtained. A set of SOLIDUSS simulations was carried out replicating the experimental setup and using literature diffusion and desorption activation parameters. The results obtained are in good agreement with the experimental data within error bars. A high sensitivity of the simulation results to changes in the input parameters was observed