Electrical Characterization of a Thin Edgeless N-on-p Planar Pixel Sensors For ATLAS Upgrades

In view of the LHC upgrade phases towards the High Luminosity LHC (HL-LHC), the ATLAS experiment plans to upgrade the Inner Detector with an all-silicon system. Because of its radiation hardness and cost effectiveness, the n-on-p silicon technology is a promising candidate for a large area pixel detector. The paper reports on the joint development, by LPNHE and FBK of novel n-on-p edgeless planar pixel sensors, making use of the active trench concept for the reduction of the dead area at the periphery of the device. After discussing the sensor technology, and presenting some sensors' simulation results, a complete overview of the electrical characterization of the produced devices will be given.Comment: 9 pages, 9 figures, to appear in the proceedings of the 15th International Workshops on Radiation Imaging Detector

Performance of Irradiated Thin Edgeless N-on-P Planar Pixel Sensors for ATLAS Upgrades

In view of the LHC upgrade phases towards the High Luminosity LHC (HL-LHC), the ATLAS experiment plans to upgrade the Inner Detector with an all-silicon system. Because of its radiation hardness and cost effectiveness, the n-on-p silicon technology is a promising candidate for a large area pixel detector. The paper reports on the joint development, by LPNHE and FBK of novel n-on-p edgeless planar pixel sensors, making use of the active trench concept for the reduction of the dead area at the periphery of the device. After discussing the sensor technology, a complete overview of the electrical characterization of several irradiated samples will be discussed. Some comments about detector modules being assembled will be made and eventually some plans will be outlined.Comment: 6 pages, 13 figures, to appear in the proceedings of the 2013 Nuclear Science Symposium and Medical Imaging Conference. arXiv admin note: text overlap with arXiv:1311.162

Development of Edgeless n-on-p Planar Pixel Sensors for future ATLAS Upgrades

The development of n-on-p "edgeless" planar pixel sensors being fabricated at FBK (Trento, Italy), aimed at the upgrade of the ATLAS Inner Detector for the High Luminosity phase of the Large Hadron Collider (HL-LHC), is reported. A characterizing feature of the devices is the reduced dead area at the edge, achieved by adopting the "active edge" technology, based on a deep etched trench, suitably doped to make an ohmic contact to the substrate. The project is presented, along with the active edge process, the sensor design for this first n-on-p production and a selection of simulation results, including the expected charge collection efficiency after radiation fluence of $1 \times 10^{15} {\rm n_{eq}}/{\rm cm}^2$ comparable to those expected at HL-LHC (about ten years of running, with an integrated luminosity of 3000 fb$^{-1}$) for the outer pixel layers. We show that, after irradiation and at a bias voltage of 500 V, more than 50% of the signal should be collected in the edge region; this confirms the validity of the active edge approach.Comment: 20 pages, 9 figures, submitted to Nucl. Instr. and Meth.

Novel Silicon n-on-p Edgeless Planar Pixel Sensors for the ATLAS upgrade

In view of the LHC upgrade phases towards HL-LHC, the ATLAS experiment plans to upgrade the Inner Detector with an all-silicon system. The n-on-p silicon technology is a promising candidate for the pixel upgrade thanks to its radiation hardness and cost effectiveness, that allow for enlarging the area instrumented with pixel detectors. We report on the development of novel n-in-p edgeless planar pixel sensors fabricated at FBK (Trento, Italy), making use of the "active edge" concept for the reduction of the dead area at the periphery of the device. After discussing the sensor technology and fabrication process, we present device simulations (pre- and post-irradiation) performed for different sensor configurations. First preliminary results obtained with the test-structures of the production are shown.Comment: 6 pages, 5 figures, to appear in the proceedings of the 9th International Conference on Radiation Effects on Semiconductor Materials Detectors and Device

Convergence of nonlocal threshold dynamics approximations to front propagation

In this note we prove that appropriately scaled threshold dynamics-type algorithms corresponding to the fractional Laplacian of order $\alpha \in (0,2)$ converge to moving fronts. When $\alpha \geqq 1$ the resulting interface moves by weighted mean curvature, while for $\alpha <1$ the normal velocity is nonlocal of ``fractional-type.'' The results easily extend to general nonlocal anisotropic threshold dynamics schemes.Comment: 19 page

Survey of detection techniques, mathematical models and simulation software in pedestrian dynamics

The study of pedestrian dynamics has become in the latest years an increasing field of research. A relevant number of technicians have been looking for improving technologies able to detect walking people in various conditions. Several researchers have dedicated their works to model walking dynamics and general laws. Many studiers have developed interesting software to simulate pedestrian behavior in all sorts of situations and environments. Nevertheless, till nowadays, no research has been carried out to analyze all the three over-mentioned aspects. The remarked lack in literature of a complete research, pointing out the fundamental features of pedestrian detection techniques, pedestrian modelling and simulation and their tight relationships, motivates the draft of this paper. Aim of the paper is, first, to provide a schematic summary of each topic. Secondly, a more detailed description of the subjects is displayed, pointing out the advantages and disadvantages of each detection technology, the working logic of each model, outlining the inputs and the provided outputs, and the main features of the simulation software. Finally, the obtained results are summarized and discussed, in order to outline the correlation among the three explained themes

Bat Skull Evolution: the Impact of Echolocation

Morphological adaptations of the mammalian skull are influenced by a variety of functional, environmental and behavioural factors. Skulls of echolocating species, such as bats, also face the challenge of optimizing sound emission and propagation. A strong association between bat skull morphology and feeding behaviour has been suggested previously (in particular for the Phyllostomidae family). Morphological variation related to other drivers of adaptation (in particular echolocation) remains understudied. In this thesis, I investigated the relationship between bat skull morphology (i.e., size and shape) and functional traits (i.e., feeding and echolocation) with a focus on the echolocation adaptations. I applied geometric morphometrics on data acquired from 3D digital models of bat skulls reconstructed with photogrammetry and μCT scan techniques. The power and limitations of photogrammetry have not been fully explored for studies of evolutionary processes of small animals. As such, I firstly demonstrated the reliability of photogrammetry for the reconstruction of 3D digital models of bat skulls by evaluating its potential for evolutionary morphology studies at the interspecific level. I found that the average distance between meshes reconstructed with different techniques (i.e., photogrammetry, μCT or laser scan) was 0.037 mm (0.25% of total skull length). Levels of random error (repeatability and Procrustes variance) were similar in all techniques and no systematic error was observed. Therefore, the same biological conclusions are obtained regardless of the reconstruction technique employed. I subsequently assessed variation in skull morphology, with respect to ecological group (i.e., diet and emission type) and functional measures (i.e., bite force, masticatory muscles and echolocation characteristics), using phylogenetic comparative methods. I found that skull diversification among bat families is mainly driven by sound emission type (i.e., nasal and oral) and broad diatary preferences. Feeding parameters (i.e., bite force and masticatory muscles) influence the shape and size of all families studied and not only in phyllostomids: bigger species generate stronger bites and species with a short rostrum generate higher bite forces relative to their body size. Sensory parameters (i.e., echolocation characteristics) scale with skull size and correlate with skull shape in insectivorous species. I estimated the relative effects of feeding and sensory functional demands on skull size and shape variation and found comparable effects within the insectivorous species. Echolocation and feeding functions appear to constrain the same skull shape characteristics (i.e., rostrum length) in insect-eating species indicating a possible functional trade-off. These species possibly underwent strong selection on skull morphology due to the (almost) exclusive use of echolocation to pursuit rapidly moving prey. Additionally, echolocation signals in bats vary in call design (i.e., number of harmonics, constant frequency, quasi-constant frequency and frequency modulation components) and some have evolved multiple times in different lineages. Therefore, I tested the effect of emission type and call design on the relationship between peak frequency and skull morphology within a broad taxonomic context (219 species). Skull morphology (i.e., size and shape) of constant frequency nasal emitting species is strongly associated with peak frequency to amplify the sound through resonance effect within the nasal chambers. Despite no resonance effect being known for oral emitting species, skull shape variation also correlates with peak frequency in these species. Spatial and mechanical demands of echolocating muscles might mould the skull shape during ontogenesis of oral emitting species: the correlation between peak frequency and shape may result from an indirect mechanical effect. Interestingly, the skull shape of some non-insectivorous species (i.e., frugivorous phyllostomids) also shows an evolutionary correlation with peak frequency. This suggests that peak frequency is still constraining skull shape of phyllostomid bats or, as phyllostomids probably evolved from an insectivorous ancestor, the adaptations to echolocation are evolutionary conservative. This thesis advances our knowledge of bat skull adaptation to echolocation and encourages future evolutionary studies to focus more on under-studied echolocation parameters

Managerial decisions to recover from Covid-19 disruption: A multi-objective optimization approach applied to public transport operators

The resilience of transport systems, facing natural or man-made disruptions, has been widely discussed in literature in terms of recovery capabilities concerning infrastructures, suggesting solutions to provide users an acceptable level of service along the interrupted network. However, in the context of the Covid-19 outbreak, the disruption has stressed the resilience of transport systems not on the supply side but rather at organizational level for transport service providers. Indeed, the sudden and drastic decrease in users due to the restrictions imposed by governments to limit the pandemic spread has implicated severe economic consequences in the running of transport companies. In this paper, attention has been focused on the public transport sector to analyse the effects of different initiatives, which companies could undertake in response to the demand shock caused by the Covid-19 emergency. Notably, an optimization procedure has been developed with the aim of determining feasible Pareto-front solutions, which correspond to trade-off conditions for the concurrent maximization of the company profit and the minimization of outsourcing services. The time span necessary to implement the examined recovery measures has been considered together with the limitation to appropriate threshold values for the main cost and income items influencing the company operations management. The proposed approach has been applied to the case study of an Italian public transport company to appraise different post-Covid-19 resilience strategies

Experimental Realization of Optimal Noise Estimation for a General Pauli Channel

We present the experimental realization of the optimal estimation protocol for a Pauli noisy channel. The method is based on the generation of 2-qubit Bell states and the introduction of quantum noise in a controlled way on one of the state subsystems. The efficiency of the optimal estimation, achieved by a Bell measurement, is shown to outperform quantum process tomography