New development of a Radiation-Hard Polycrystalline CdTe Detector for LHC Luminosity Monitoring

Detectors presently considered for monitoring and control of the LHC luminosity will sample the hadronic/electromagnetic showers produced by neutrons and photons in copper absorbers designed to protect the superconducting magnets from quenching. At this location the detectors will have to withstand extreme radiation levels and their long term operation will have to be assured without requiring human intervention. For this application we have successfully tested thick polycrystalline-CdTe detectors. The paper summarizes the results obtained on rise-times, sensitivity and resistance to neutron irradiation up to a dose of 10 ^15/cm 2

Contribution à l'intégration de la fiabilité dansle flôt de conception des circuits intégrés fondée sur l'utilisation d'un langage de description comportementale VHDL-AMS

L'évolution croissante des technologies CMOS entraîne le renouvellement des techniques de prédiction de la fiabilité des circuits. Les méthodes statistiques ne suffisent plus pour évaluer la fiabilité des circuits à forte intégration. De nouvelles techniques de prédiction de fiabilité doivent être définies et mises en place afin de répondre rapidement aux contraintes d'analyse de la fiabilité. Une étude de la fiabilité des circuits CMOS doit être prise en charge en amont de la production. Pour cela, il est nécessaire de tenir compte de la dépendance des dispositifs élémentaires aux mécanismes de dégradation au cours du flot de conception des circuits. A partir d'un modèle électrique de dégradation du transistor MOSFET, fondé sur le langage de description comportementale VHDL-AMS, il est démontré qu'une prédiction de la fiabilité des circuits CMOS est réalisable à partir de simulations électriques. Une validation est réalisée à partir d'un circuit CMOS de démonstration : l'amplificateur opérationnel de transconductance. L'intérêt de cette méthode est sa reproductibilité pour la construction de modèles VHDL-AMS de dégradation de circuits CMOS d'abstraction supérieure dans le but d'analyser la fiabilité des systèmes.The increasing CMOS process evolution involves the renewal of the techniques to predict the circuits reliability. The statistical methods are not enough any more to evaluate the reliability of the VLSI circuits. New techniques of reliability prediction must be defined and implemented in order to quickly answer to the constraints of reliability analysis. A study of the CMOS circuits reliability must be dealt with upstream production. Then, it is necessary to hold account the dependence of the elementary devices with the degradation mechanisms during the circuit design flow. From a degradation electric model of transistor MOSFET, founded on the VHDL-AMS behavioral modelling language, it is shown that a prediction of the CMOS circuits reliability is realizable starting from electric simulations. A validation is carried out starting from a CMOS circuit demonstration : the operational transconductance amplifier. The method interest is its reproducibility to build degradation VHDL-AMS models of CMOS circuits with higher description abstraction in order to analyze the reliability of the electronics systems

Regenerative braking for an electric vehicle with a high-speed drive at the front axle

The main contribution of this paper lies in the development of a novel front-to-rear axle brake force distribution strategy for the regenerative braking control of a vehicle with a high-speed electric drive unit at the front axle. The strategy adapts the brake proportioning to provide extended room for energy recuperation of the electric motor when the vehicle drivability and safety requirements permit. In detail, the strategy is adaptive to cornering intensity enabling the range to be further extended in real-world applications. The regenerative braking control features a brake blending control algorithm and a powertrain controller, which are decisive for enhancing the braking performance. Lastly, the regenerative braking control is implemented in the highfidelity simulation environment Simcenter Amesim, where system efficiency and regenerative brake performance are analysed. Results confirm that the designed regenerative braking greatly improves the effectiveness of energy recuperation for a front-wheel driven electric vehicle with a high-speed drive at the front axle. In conclusion, it is shown that it is feasible to use the high-speed drive with the proposed control design for regenerative braking

Échantillonnage préférentiel et méta-modèles : méthodes bayésiennes optimale et défensive

National audienceThis paper considers the problem of the choice of an instrumental distribution for the estimation by preferential sampling of an integral $\int h(x) \pi(x)\, {\rm d}x$, where the function $h$ is expensive to evaluate. To build such an instrumental distribution, we adopt a Bayesian approach where we introduce a prior about $h$, which makes it possible to construct a Bayes-optimal instrumental distribution, given evaluation results of $h$. This instrumental distribution minimizes the expectation (with respect to the prior distribution about $h$) of the (frequentist) variance of estimation. However, the variance of estimation obtained using this instrumental distribution can be larger than that of the Monte Carlo estimator in some cases. We present a "defensive" correction of the Bayes-optimal instrumental distribution to address this issue. We illustrate the approach on a problem of estimation of a probability of failure, based on an industrial numerical simulator from the domain of structural reliability.Cet article considère le problème du choix d'une loi instrumentale pour l'estimation par échantillonnage préférentiel d'une intégrale du type $\int h(x) \pi(x)\, {\rm d}x$, la fonction $h$ étant coûteuse à évaluer. Pour construire une telle loi instrumentale, nous adoptons une approche bayésienne consistant à introduire un a priori sur $h$, ce qui permet, étant donnés des résultats d'évaluations de $h$, de construire une loi instrumentale optimale au sens bayésien. Cette loi instrumentale, bien que permettant de réduire l'espérance (par rapport à la loi a priori) de la variance fréquentiste d’estimation, peut conduire dans certains cas à une variance supérieure à celle de l'estimateur de Monte Carlo. Nous proposons une correction, dite "défensive", de la loi optimale bayésienne pour remédier à ce problème. Une application à l'estimation d'une probabilité de défaillance, à partir d'un code industriel issu du domaine de la fiabilité des structures, illustre l'approche proposée

CdTe Photoconductors for LHC Luminosity Monitoring

Detectors using CdTe photoconductors are being used with great success in LEP to monitor the vertical beam emittance. They can withstand tremendous irradiation, of up to 10^13 Gy, from hard X-rays. For the LHC, monitors measuring the relative luminosity will be placed inside absorbers located 142 m from the interaction points, where they will receive about 10^8 Gy per year due to gamma radiation and neutrons. Thick-polycristalline-CdTe detectors were recently tested for speed, sensitivity and radiation resistance before and after receiving up to 10^15 neutrons per cm^2. The test results are presented here, along with a comparison of the calculated charge deposition in Silicon, Diamond and GaAs detectors

Fast Polycrystalline-CdTe Detectors for LHC Luminosity Measurements

Beam diagnostics in future high-energy accelerators will require long lived instrumentation in highly hostile radiation environments. A research program aiming at individuating new solutions and testing them under extreme operational conditions has been launched at CERN in the framework of developments for the LHC instrumentation. Its outcome might be used in future accelerator projects, in industry or in physics applications. The detectors which will be adopted for the LHC luminosity monitoring and optimization will be installed close to or inside copper absorbers specifically designed for radiation protection of the accelerator magnetic elements in the interaction regions. These detectors will have to withstand extreme radiation levels and their long-term operation has to be assured without requiring human intervention. Polycrystalline-CdTe detectors have demonstrated their radiation hardness against extreme doses of X-ray exposure in the LEP collider and are considered as good candidates for LHC luminosity monitoring applications. After recalling a series of measurements obtained on CdTe samples exposed to different sources to study their time response and sensitivity we present results on their performance after irradiation at doses of 10^16 neutrons/cm^2. This is a preliminary step in the program intended to test the samples during and after irradiation up to levels of 10^18 neutrons/cm^2 and 10^16 protons/cm^2 comparable to those anticipated at the detector locations over ten years of operation of the accelerator

Isolated receptor binding domains of HTLV-1 and HTLV-2 envelopes bind Glut-1 on activated CD4+ and CD8+ T cells

<p>Abstract</p> <p>Background</p> <p>We previously identified the glucose transporter Glut-1, a member of the multimembrane-spanning facilitative nutrient transporter family, as a receptor for both HTLV-1 and HTLV-2. However, a recent report concluded that Glut-1 cannot serve as a receptor for HTLV-1 on CD4 T cells: This was based mainly on their inability to detect Glut-1 on this lymphocyte subset using the commercial antibody mAb1418. It was therefore of significant interest to thoroughly assess Glut-1 expression on CD4 and CD8 T cells, and its association with HTLV-1 and -2 envelope binding.</p> <p>Results</p> <p>As previously reported, ectopic expression of Glut-1 but not Glut-3 resulted in significantly augmented binding of tagged proteins harboring the receptor binding domains of either HTLV-1 or HTLV-2 envelope glycoproteins (H1_RBDor H2_RBD). Using antibodies raised against the carboxy-terminal peptide of Glut-1, we found that Glut-1 expression was significantly increased in both CD4 and CD8 cells following TCR stimulation. Corresponding increases in the binding of H1_RBDas well as H2_RBD, not detected on quiescent T cells, were observed following TCR engagement. Furthermore, increased Glut-1 expression was accompanied by a massive augmentation in glucose uptake in TCR-stimulated CD4 and CD8 lymphocytes. Finally, we determined that the apparent contradictory results obtained by Takenouchi et al were due to their monitoring of Glut-1 with a mAb that does not bind cells expressing endogenous Glut-1, including human erythrocytes that harbor 300,000 copies per cell.</p> <p>Conclusion</p> <p>Transfection of Glut-1 directly correlates with the capacities of HTLV-1 and HTLV-2 envelope-derived ligands to bind cells. Moreover, Glut-1 is induced by TCR engagement, resulting in massive increases in glucose uptake and binding of HTLV-1 and -2 envelopes to both CD4 and CD8 T lymphocytes. Therefore, Glut-1 is a primary binding receptor for HTLV-1 and HTLV-2 envelopes on activated CD4 as well as CD8 lymphocytes.</p

Identification of transcriptional regulatory variants in pig duodenum, liver, and muscle tissues

Background In humans and livestock species, genome-wide association studies (GWAS) have been applied to study the association between variants distributed across the genome and a phenotype of interest. To discover genetic polymorphisms affecting the duodenum, liver, and muscle transcriptomes of 300 pigs from 3 different breeds (Duroc, Landrace, and Large White), we performed expression GWAS between 25,315,878 polymorphisms and the expression of 13,891 genes in duodenum, 12,748 genes in liver, and 11,617 genes in muscle. Results More than 9.68 × 1011 association tests were performed, yielding 14,096,080 significantly associated variants, which were grouped in 26,414 expression quantitative trait locus (eQTL) regions. Over 56% of the variants were within 1 Mb of their associated gene. In addition to the 100-kb region upstream of the transcription start site, we identified the importance of the 100-kb region downstream of the 3′UTR for gene regulation, as most of the cis-regulatory variants were located within these 2 regions. We also observed 39,874 hotspot regulatory polymorphisms associated with the expression of 10 or more genes that could modify the protein structure or the expression of a regulator gene. In addition, 2 motifs (5′-GATCCNGYGTTGCYG-3′ and a poly(A) sequence) were enriched across the 3 tissues within the neighboring sequences of the most significant single-nucleotide polymorphisms in each cis-eQTL region. Conclusions The 14 million significant associations obtained in this study are publicly available and have enabled the identification of expression-associated cis-, trans-, and hotspot regulatory variants within and across tissues, thus shedding light on the molecular mechanisms of regulatory variations that shape end-trait phenotypes.info:eu-repo/semantics/publishedVersio

Saumur. Restauration de la grande vis du château

Litoux Emmanuel, Mongellaz Jacqueline. Saumur. Restauration de la grande vis du château. In: Bulletin Monumental, tome 171, n°3, année 2013. pp. 254-257