Search results for "Detector"
showing 10 items of 3491 documents
Measurement of the Higgs boson coupling with tau leptons and search for an additional neutral MSSM Higgs boson with the ATLAS detector
2018
El Modelo Estándar de física de partículas (SM), la teoría que describe el comportamiento de las partículas subatómicas, ha sido un éxito en su precisión y exactitud. Uno de sus pilares básicos es el mecanismo de Higgs, que regula los términos de masa de las partículas fundamentales. La partícula responsable de este mecanismo es el bosón de Higgs, que fue descubierto en 2012 en los experimentos ATLAS y CMS del colisionador de partículas LHC del CERN, mediante el análisis de su acoplamiento a partículas bosónicas (fotones y bosones W y Z). Tras su descubrimiento, es necesario confirmar que el resto sus propiedades se corresponden con las predichas por el SM, como, por ejemplo, su acoplamient…
Performance Improvements of EventIndex Distributed System at CERN
2023
El trabajo de esta tesis se enmarca dentro del proyecto EventIndex del experimento ATLAS, un gran detector de partı́culas del LHC (Gran Colisionador de Hadrones) en el CERN. El objetivo del proyecto es catalogar todas las colisiones de partı́culas, o eventos, registrados en el detector ATLAS y también simulados a lo largo de sus años de funcionamiento. Con este catálogo se pueden caracterizar los datos a nivel de evento para su búsqueda y localización por parte de los usuarios finales. También se pueden realizar comprobaciones en la cadena de registro y reprocesado de los datos, para comprobar su corrección y optimizar futuros procesos. Debido al incremento en las tasas y volumen de datos e…
UV Metal Semiconductor Metal Detectors. A Robust Choice for (Al,Ga)N Based Detectors
2004
UV detection is interesting for combustion optimization, air contamination control, fire and solar blind rocket launching detection. Most of these applications require that UV detectors have a huge dynamic response between UV and the visible, and a very low dark current in the range of the UV flux measured. (Al,Ga)N alloys present a large direct bandgap in this range and therefore can be used as an active region in such detectors. To take advantage of the large Schottky barrier, the good alloy quality, and to avoid any doping problems, we have developed MSM photodetectors. High quality material has been grown with MOCVD and MBE on sapphire substrates. Stress management is employed for alumi…
Thermoelectric radiation detector based on a superconductor-ferromagnet junction : Calorimetric regime
2018
We study the use of a thermoelectric junction as a thermal radiation detector in the calorimetric regime, where single radiation bursts can be separated in time domain. We focus especially on the case of a large thermoelectric figure of merit ZT affecting significantly, for example, the relevant thermal time scales. This work is motivated by the use of hybrid superconductor/ferromagnet systems in creating an unprecedentedly high low-temperature ZT even exceeding unity. Besides constructing a very general noise model which takes into account cross correlations between charge and heat noise, we show how the detector signal can be efficiently multiplexed by the use of resonant LC circuits givi…
Global analysis of the pMSSM in light of the Fermi GeV excess: prospects for the LHC Run-II and astroparticle experiments
2016
We present a new global fit of the 19-dimensional phenomenological Minimal Supersymmetric Standard Model (pMSSM-19) that comply with all the latest experimental results from dark matter indirect, direct and accelerator dark matter searches. We show that the model provides a satisfactory explanation of the excess of gamma-rays from the Galactic centre observed by the Fermi~Large Area Telescope, assuming that it is produced by the annihilation of neutralinos in the Milky Way halo. We identify two regions that pass all the constraints: the first corresponds to neutralinos with a mass ~80-100 GeV annihilating into WW with a branching ratio of 95% ; the second to heavier neutralinos, with mass ~…
Paschen β line shape studies in low-temperature plasmas
2003
Line shape calculations and measurements of the Paschen β line of hydrogen (λ=12818 Å) are reported. Measurements were performed at electron densities of the plasma between 1015 cm-3 and 1016 cm-3. A wall-stabilized arc operated at atmospheric pressure in a helium-hydrogen gas mixture was applied as the excitation source. The radiation of the plasma, originating from nearly homogeneous plasma layers, in the end-on direction, was analyzed. A grating spectrometer equipped with a CCD detector was used for the radiation detection. The measured line profiles are compared with results of available experimental and theoretical Stark broadening data e.g. based on simulation techniques, applied also…
CERN IRRADIATION FACILITIES.
2017
CERN provides unique irradiation facilities for applications in dosimetry, metrology, intercomparison of radiation protection devices, benchmark of Monte Carlo codes and radiation damage studies to electronics.
Modelling Recurrent Events for Improving Online Change Detection
2016
The task of online change point detection in sensor data streams is often complicated due to presence of noise that can be mistaken for real changes and therefore affecting performance of change detectors. Most of the existing change detection methods assume that changes are independent from each other and occur at random in time. In this paper we study how performance of detectors can be improved in case of recurrent changes. We analytically demonstrate under which conditions and for how long recurrence information is useful for improving the detection accuracy. We propose a simple computationally efficient message passing procedure for calculating a predictive probability distribution of …
Survey of Research for Performance Measurement of Mobile Manipulators
2016
International audience; This survey provides the basis for developing research in the area of mobile manipulator performance measurement, an area that has relatively few research articles when compared to other mobile manipulator research areas. The survey provides a literature review of mobile manipulator research with examples of experimental applications. The survey also provides an extensive list of planning and control references as this has been the major research focus for mobile manipulators which factors into performance measurement of the system. The survey then reviews performance metrics considered for mobile robots, robot arms, and mobile manipulators and the systems that measu…
Measurement of the top quark charge in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
2013
A measurement of the top quark electric charge is carried out in the ATLAS experiment at the Large Hadron Collider using 2.05 fb[superscript −1] of data at a centre-of-mass energy of 7 TeV. In units of the elementary electric charge, the top quark charge is determined to be 0.64 ± 0.02 (stat.) ± 0.08 (syst.) from the charges of the top quark decay products in single lepton t[¯ over t] candidate events. This excludes models that propose a heavy quark of electric charge −4/3, instead of the Standard Model top quark, with a significance of more than 8σ.