34 research outputs found

    Development of Single- and Double-sided Ladders for the ILD Vertex Detectors

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    We discuss two projects exploring the integration of thin CMOS pixel sensors in order to prototype ladders matching the geometry needed for the ILD vertex detector. The PLUME project has designed and fabricated full-size and fully functional double- sided layers which currently reach 0.6 % X0 and aim for 0.3 % X0 in mid-2012. Another approach, SERNWIETE, consists in wrapping the sensors in a polyimide-based micro-cable to obtain a supportless single-sided ladder with a material budget around 0.15 % X0. First promising samples have been produced and the full-size prototype is expected in spring 2012.Comment: International Workshop on Future Linear Colliders, LCWS 2011, Granada, Spain, 2011, 26-30 Septembe

    Status of the Micro Vertex Detector of the Compressed Baryonic Matter Experiment

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    The CBM experiment will investigate heavy-ion collisions at beam energies from 8 to 45 AGeV at the future accelerator facility FAIR. The goal of the experiment is to study the QCD phase diagram in the vincinity of the QCD critical point. To do so, CBM aims at measuring rare probes among them open charm. In order to identify those rare and short lived particles despite the rich combinatorial background generated in heavy ion collisions, a micro vertex detector (MVD) providing an unprecedented combination of high rate capability and radiation hardness, very light material budget and excellent granularity is required. In this work, we will discuss the concept of this detector and summarize the status of the R&D

    Combining satellite, aerial and ground measurements to assess forest carbon stocks in Democratic Republic of Congo

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    peer reviewedMonitoring tropical forest carbon stocks changes has been a rising topic in the recent years as a result of REDD+ mechanisms negotiations. Such monitoring will be mandatory for each country willing to benefit from these financial incentives in the future. Aerial and satellite remote sensing technologies offer cost advantages in implementing large scale forest inventories. Despite the recent progress made in the use of airborne LiDAR for C stocks estimation, no widely operational and cost effective method has yet been delivered for central Africa forest monitoring. Within the Maï Ndombe region of DRC, the EO4REDD project develops a method combining satellite, aerial and ground measurements. This combination is done in three steps: [1] mapping and quantifying forest cover changes using an object-based semi-automatic change detection (deforestation and forest degradation) methodology based on very high resolution satellite imagery (RapidEye), [2] developing an allometric linear model for above ground biomass measurements based on dendrometric parameters (tree crown areas and heights) extracted from airborne stereoscopic image pairs and calibrated using ground measurements of individual trees on a data set of 18 one hectare plots and [3] relating these two products to assess carbon stocks changes at a regional scale. Given the high accuracies obtained in [1] (> 80% for deforestation and 77% for forest degradation) and the suitable, but still to be improved with a larger calibrating sample, model (R2 of 0.7) obtained in [2], EO4REDD products can be seen as a valid and replicable option for carbon stocks monitoring in tropical forests. Further improvements are planned to strengthen the cost effectiveness value/REDD+ suitability in the 2nd phase of EO4REDD. This 2nd phase will include [A] specific model developments per forest type; [B] measurements of afforestation, reforestation and natural regeneration processes and [C] study of Sentinel data series potential use

    Advanced modulation format using silicon modulators in the O-band

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    International audienceThis paper review our recent work on silicon modulators based on free carrier concentration, working in the O-band of optical communications (1260 nm-1360 nm) for short distance applications. 25 Gbit/s OOK modulation is obtained using a driving voltage of 3.3 Vpp , and QPSK dual-drive Mach-Zehnder modulator (DDMZM) operating in the O-band is demonstrated for the first time

    20-Gbps QPSK signal generation using a silicon dual-drive Mach-Zehnder modulator operating in the O-Band

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    International audience20-Gbps QPSK modulation in the O-band is experimentally demonstrated using a simple transmitter structure based on a silicon dual-drive Mach-Zehnder modulator. A power penalty of only 1.5 dB was obtained with respect to the same transmitter structure in LiNbO3

    O-Band QPSK modulation based on a silicon dual-drive Mach-Zehnder

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    International audienceAdvanced modulation formats will be required in next generation optical interconnects in order to keep up with future bandwidth demand. In this work QPSK modulation in the O-band is experimentally demonstrated using a silicon-based dual-drive Mach-Zehnder modulator

    Silicon modulators for the generation of advanced modulation formats

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    International audienceSilicon photonics has appeared in the recent years as the best suited technology for fulfilling the demands of future optical interconnects. In this framework, modulators are key elements in the performance of an optical link. In order to achieve modulation in silicon the Free-Carrier Plasma Dispersion (FCPD) effect is normally used. In fact, silicon modulators based on carrier depletion have been demonstrated with outstanding performance up to 40Gbps. However, keeping up with bandwidth demands will require the use of more complex modulation formats like PAM4 or QPSK. At the same time, to avoid dispersion compensation circuits, the use of the O-Band (1260nm-1360nm) is preferred for short range optical communications. In this work we present our results on the generation of BPSK/QPSK signals using silicon modulators
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