Search results for "cavities"
showing 3 items of 33 documents
Etude en champ proche et en champ lointain de composants périodiquement nanostructurés : cristaux photoniques et tamis à photons
2004
Recently, a new class of optical components is appeared. Its main characteristic is to be formed by a periodical sub-wavelength pattern, leading to the apparition of a spectral domain where propagation of light inside the structure is forbidden -- a photonic bandgap. This work is devoted to the study in the near- and far-field of two kinds of periodical optical components: photonic crystals (PCs) and nanostructured metallic films that exhibit the so-called enhanced transmission. First, we study two-dimensional PCs with a scanning near-field optical microscope (SNOM) in collection mode. With this SNOM, we directly map the intensity distribution inside PC-based microcavities. We also evidence…
The advanced Virgo longitudinal control system for the O2 observing run
2020
Following a successful period of data-taking between 2006 and 2011, the Virgo gravitational-wave detector was taken offline for a major upgrade. The changes made to the instrument significantly increased the complexity of the control systems and meant that an extended period of commissioning was required to reach a sensitivity appropriate for science data-taking. This commissioning period was completed in July of 2017 and the second-generation Advanced Virgo detector went on to join the Advanced LIGO detectors in the O2 science run in August of the same year. The upgraded detector was approximately twice as sensitive to binary neutron star mergers as the first-generation instrument. During …
Dynamical analysis of electron transport in RF cavities and photomultipliers tubes
2021
El objetivo de este trabajo es el estudio de la dinámica de haces y corrientes de electrones en cavidades aceleradoras de radiofrecuencia (RF) y en tubos fotomultiplicadores. Por una parte, los haces de electrones presentan una gran importancia histórica tanto en aplicaciones directas (televisiones, hornos de microondas, tratamiento del cáncer), como en la generación de radiación sincrotrón. La última generación de fuentes de rayos X muy brillantes se basa en los láseres de electrones libres (XFEL). No obstante, para producir los haces de electrones que emitirán dichos rayos X como radiación sincrotrón, se necesitan campos eléctricos de gran intensidad lo que produce que, debido a la emisió…