1,081 research outputs found

    Geiger-Mode Avalanche Photodiodes in Particle Detection

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    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite sensitivity and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection remains still unexplored. In this contribution, we are going to expose the different steps that we have taken in order to prove the efficiency of Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present an array of pixels of 1mmx1mm fabricated with a standard CMOS technology for characterization in a test beam.Comment: 7 pages, 2 figures, Proceedings of LCWS1

    Development of high voltage-CMOS sensors within the CERN-RD50 collaboration

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    This paper presents work done by the CERN-RD50 collaboration to develop and study monolithic CMOS sensors for future hadron colliders, especially in terms of radiation tolerance, time resolution and granularity. Currently CERN-RD50 is completing the performance evaluation of RD50-MPW2 and has recently submitted RD50-MPW3, the second and third prototype sensor chips designed by the collaboration. The paper gives an overview of the main design aspects and performance evaluation results of the first two prototype chips RD50-MPW1 and RD50-MPW2, and details the design of the latest prototype RD50-MPW3. RD50-MPW2 is a small prototype with an 8 x 8 matrix of active pixels which implement analogue readout electronics only and solutions for low leakage currents. This prototype has been evaluated in the laboratory and also at proton and ion beam facilities, before and after irradiation with neutrons up to 2⋅1015 neq/cm 2. RD50-MPW3 is a more advanced prototype with a matrix of 64 x 64 pixels which integrate both analogue and digital readout electronics inside the sensing diodes. To alleviate routing congestion and minimise crosstalk noise, the pixels are serially configured and organised in a double column scheme. This prototype has optimised peripheral readout electronics for effective chip configuration, based on the I2C protocol, and fast data transmission

    Characterisation of AMS H35 HV-CMOS monolithic active pixel sensor prototypes for HEP applications

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    Monolithic active pixel sensors produced in High Voltage CMOS (HV-CMOS) technology are being considered for High Energy Physics applications due to the ease of production and the reduced costs. Such technology is especially appealing when large areas to be covered and material budget are concerned. This is the case of the outermost pixel layers of the future ATLAS tracking detector for the HL-LHC. For experiments at hadron colliders, radiation hardness is a key requirement which is not fulfilled by standard CMOS sensor designs that collect charge by diffusion. This issue has been addressed by depleted active pixel sensors in which electronics are embedded into a large deep implantation ensuring uniform charge collection by drift. Very first small prototypes of hybrid depleted active pixel sensors have already shown a radiation hardness compatible with the ATLAS requirements. Nevertheless, to compete with the present hybrid solutions a further reduction in costs achievable by a fully monolithic design is desirable. The H35DEMO is a large electrode full reticle demonstrator chip produced in AMS 350 nm HV-CMOS technology by the collaboration of Karlsruher Institut f\"ur Technologie (KIT), Institut de F\'isica d'Altes Energies (IFAE), University of Liverpool and University of Geneva. It includes two large monolithic pixel matrices which can be operated standalone. One of these two matrices has been characterised at beam test before and after irradiation with protons and neutrons. Results demonstrated the feasibility of producing radiation hard large area fully monolithic pixel sensors in HV-CMOS technology. H35DEMO chips with a substrate resistivity of 200Ω\Omega cm irradiated with neutrons showed a radiation hardness up to a fluence of 101510^{15}neq_{eq}cm2^{-2} with a hit efficiency of about 99% and a noise occupancy lower than 10610^{-6} hits in a LHC bunch crossing of 25ns at 150V

    DDR1 (discoidin domain receptor tyrosine kinase 1)

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    Review on DDR1 (discoidin domain receptor tyrosine kinase 1), with data on DNA, on the protein encoded, and where the gene is implicated

    Atividade biológica das toxinas do Bt, Cry 1A(b) e Cry 1F em Spodoptera frugiperda (Smith) (Lepidoptera: noctuidae).

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    Atualmente, há duas diferentes toxinas do Bacillus thuringiensis (Bt) disponíveis em milho transgênico. Entretanto, há poucas informações sobre a toxicidade dessas proteínas puras Cry 1A(b) e Cry 1F para a lagarta-do-cartucho do milho (LCM), Spodoptera frugiperda, (Smith) usando o método de tratamento superficial da dieta. Os bioensaios foram conduzidos, usando um gradiente de concentração para as duas toxinas. Cada tratamento foi infestado artificialmente com larvas da LCM recém-eclodidas e mantidas sob temperatura constante e no escuro. Dez dias após a infestação, o número de larvas sobreviventes e a inibição de crescimento baseado na biomassa foram avaliados. Os dados de mortalidade foram submetidos à análise de "Probit". As CL50 estimadas para Cry1A(b) e Cry1F foram, respectivamente, 689,81 ng/cm2 e 36,46 ng/cm2. A CL50 foi suficiente para inibir o acúmulo de biomassa das larvas em 91,61% e 89,81% para Cry1Ab e Cry1F, respectivamente. As larvas que sobreviveram por dez dias nas dietas tratadas com o Cry 1A(b) foram transferidas para dieta não tratadas e observadas até a emergência dos adultos. Das larvas sobreviventes, 62,8% recuperaram seu desenvolvimento, acumulando a biomassa de uma pupa normal. Portanto, a atividade biológica da toxina do Bt vai além da simples toxicidade, incluindo uma significativa inibição de alimentação. Esse fato tem implicações importantes para o desenvolvimento de estratégias para o manejo da resistência

    Selection of the fall armyworm Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) for survival on Cry 1A (b) Bt toxin.

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    Plantas transgênicas que expressam toxinas da bactéria Bacillus thuringiensis (Bt) representam um importante avanço para o controle de lepidópteros-pragas de milho. Híbridos de milho Bt expressando a toxina Cry1A(b) têm mostrado significativo nível de resistência à lagarta-do-cartucho (LCM), Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), embora larvas dessa espécie tenham sido observadas em campo e em laboratório sobrevivendo nesses híbridos. Resistência de S. frugiperda também tem sido registrada para diferentes inseticidas. Em bioensaios, seleção de insetos sobreviventes mostrou um aumento do nível de tolerância à toxina do Bt Cry1A(b) em populações da lagarta-do-cartucho, após quatro gerações, indicando que essa tolerância é herdada. Palavras-chave: Insecta, resistência, plantas transgênicas

    Design and characterization of the monolithic matrices of the H35DEMO chip

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    Prototyping of an HV-CMOS demonstrator for the High Luminosity-LHC upgrade

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    HV-CMOS sensors can offer important advantages in terms of material budget, granularity and cost for large area tracking systems in high energy physics experiments. This article presents the design and simulated results of an HV-CMOS pixel demonstrator for the High Luminosity-LHC. The pixel demonstrator has been designed in the 0.35 μm HV-CMOS process from ams AG and submitted for fabrication through an engineering run. To improve the response of the sensor, different wafers with moderate to high substrate resistivities are used to fabricate the design. The prototype consists of four large analog and standalone matrices with several pixel flavours, which are all compatible for readout with the FE-I4 ASIC. Details about the matrices and the pixel flavours are provided in this article
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