La restauración de los estudios en los seminarios

Copia digital : Junta de Castilla y León. Consejería de Cultura y Turismo, 201

High-speed railway tunnel monitoring using point, long gauge and distributed strain and temperature fiber optic sensors

La monitorización de estructuras es una rama de la ingeniería estructural que está captando mucha atención actualmente. Las deformaciones y temperaturas son, habitualmente, los parámetros monitorizados porque son los que mejor representan el comportamiento estructural. De todos los tipos de sensores existentes, los basados en fibra óptica resultan especialmente interesantes debido a sus ventajas comparativas sobre los sensores convencionales. En este artículo se presentan los trabajos de monitorización de la estructura de un túnel artificial de Alta Velocidad construido en Mogente (España) mediante tres tipos de sensores ópticos desarrollados por los autores. Los resultados de los sensores se comparan con los proporcionados por un modelo teórico de elementos finitos. Esta comparación confirma que los sensores reproducen notablemente bien la pauta general de comportamiento de la estructura, incluso con pequeños niveles de deformación (5µε). Por último, el artículo discute el comportamiento de los sensores, sus mediciones y sus campos de aplicación.Structural Health Monitoring (SHM) is presently having a great development. Strains and temperatures are usually the key parameters to be monitored due to their relevance when explaining structural behavior. Several types of sensors are used in SHM, but fiber optic sensors are especially interesting due to their advantages with respect to conventional sensors. In this paper, the monitoring of a high-speed train tunnel recently built in Spain using three types of fiber optic sensors developed by the authors is shown. Results given by the sensors are compared to those provided by a theoretical model built using FEM. Comparison of measurements and theoretical results confirms that the sensors reproduced remarkably well the general patterns of the tunnel structural behavior, even when strains are relatively small (around 5 µε). Finally, the paper discusses the behavior of the sensors, their measurements and their field of application which is useful for researchers and practitioners.Los autores quieren agradecer a la Universitat Politècnica de València, al Ministerio de Educación por la financiación recibida a través del proyecto BIA2011-27104 y al Ministerio de Fomento por el apoyo recibido a través del Proyecto SOPROMAC (P41/08)

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR

VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of $-2.49\pm0.01$ prior to a break at $(45.7\pm0.1$) TeV, followed by an index of $-2.71\pm0.01$. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review