Optimization of thin n-in-p planar pixel modules for the ATLAS upgrade at HL-LHC

The ATLAS experiment will undergo around the year 2025 a replacement of the tracker system in view of the high luminosity phase of the LHC (HL-LHC) with a new 5-layer pixel system. Thin planar pixel sensors are promising candidates to instrument the innermost region of the new pixel system, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. The sensors of 50-150 $\mu$m thickness, interconnected to FE-I4 read-out chips, have been characterized with radioactive sources and beam tests. In particular active edge sensors have been investigated. The performance of two different versions of edge designs are compared: the first with a bias ring, and the second one where only a floating guard ring has been implemented. The hit efficiency at the edge has also been studied after irradiation at a fluence of $10^{15}$ \neqcm. Highly segmented sensors will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. In order to reproduce the performance of 50x50 $\mu$m$^2$ pixels at high pseudo-rapidity values, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angles with respect to the short pixel direction. Results on the hit efficiency in this configuration are discussed for different sensor thicknesses

Particle interactions mediated by dynamical networks: assessment of macroscopic descriptions

We provide a numerical study of the macroscopic model of [3] derived from an agent-based model for a system of particles interacting through a dynamical network of links. Assuming that the network remodelling process is very fast, the macroscopic model takes the form of a single aggregation diffusion equation for the density of particles. The theoretical study of the macroscopic model gives precise criteria for the phase transitions of the steady states, and in the 1-dimensional case, we show numerically that the stationary solutions of the microscopic model undergo the same phase transitions and bifurcation types as the macroscopic model. In the 2-dimensional case, we show that the numerical simulations of the macroscopic model are in excellent agreement with the predicted theoretical values. This study provides a partial validation of the formal derivation of the macroscopic model from a microscopic formulation and shows that the former is a consistent approximation of an underlying particle dynamics, making it a powerful tool for the modelling of dynamical networks at a large scale

LES INTERACTIONS CONTROLE / APPRENTISSAGE ORGANISATIONNEL : PROPOSITION D'UNE GRILLE D'ANALYSE

International audienceLes systèmes de contrôle sont fréquemment décrits comme bloquant l'apprentissage organisationnel. La réalité est beaucoup plus complexe. Une grille d'analyse a été développée pour étudier de manière systématique les interactions entre contrôle et apprentissage organisationnel. Son application au cas d'une banque de détail permettra d'évaluer sa pertinence

LES INTERACTIONS CONTROLE / APPRENTISSAGE ORGANISATIONNEL : PROPOSITION D'UNE GRILLE D'ANALYSE

Les systèmes de contrôle sont fréquemment décrits comme bloquant l'apprentissage organisationnel. La réalité est beaucoup plus complexe. Une grille d'analyse a été développée pour étudier de manière systématique les interactions entre contrôle et apprentissage organisationnel. Son application au cas d'une banque de détail permettra d'évaluer sa pertinence.Contrôle de gestion; Contrôle organisationnel; Apprentissage organisationnel

Performance of irradiated thin n-in-p planar pixel sensors for the ATLAS Inner Tracker upgrade

The ATLAS collaboration will replace its tracking detector with new all silicon pixel and strip systems. This will allow to cope with the higher radiation and occupancy levels expected after the 5-fold increase in the luminosity of the LHC accelerator complex (HL-LHC). In the new tracking detector (ITk) pixel modules with increased granularity will implement to maintain the occupancy with a higher track density. In addition, both sensors and read-out chips composing the hybrid modules will be produced employing more radiation hard technologies with respect to the present pixel detector. Due to their outstanding performance in terms of radiation hardness, thin n-in-p sensors are promising candidates to instrument a section of the new pixel system. Recently produced and developed sensors of new designs will be presented. To test the sensors before interconnection to chips, a punch-through biasing structure has been implemented. Its design has been optimized to decrease the possible tracking efficiency losses observed. After irradiation, they were caused by the punch-through biasing structure. A sensor compatible with the ATLAS FE-I4 chip with a pixel size of 50x250 $\mathrm{\mu}$m$^{2}$, subdivided into smaller pixel implants of 30x30 $\mathrm{\mu}$m$^{2}$ size was designed to investigate the performance of the 50x50 $\mathrm{\mu}$m$^{2}$ pixel cells foreseen for the HL-LHC. Results on sensor performance of 50x250 and 50x50 $\mathrm{\mu}$m$^{2}$ pixel cells in terms of efficiency, charge collection and electric field properties are obtained with beam tests and the Transient Current Technique

ENJEUX - 2.4

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Stratégie d'inclusion dans les universités - 1.3

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ENJEUX - 2.1

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ENJEUX - 2.3

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