1,728,839 research outputs found
The MAPS-based vertex detector for the STAR experiment: Lessons learned and performance
No full textThe PiXeL detector (PXL) of the STAR experiment at RHIC is the first application of the state-of-the-art thin Monolithic Active Pixel Sensors (MAPS) technology in a collider environment. The PXL, together with the Intermediate Silicon Tracker (IST) and the Silicon Strip Detector (SSD), form the Heavy Flavor Tracker (HFT), which has been designed to improve the vertex resolution and extend the STAR measurement capabilities in the heavy flavor domain, providing a clean probe for studying the Quark–Gluon Plasma
Multi-Exponential Analysis of DLTS by Contin
No full textAbstractDeep level transient spectroscopy (DLTS), which assumes a single exponential decay form for the transient junction capacitance, is the most commonly used method to characterize deep impurity levels in semiconductors. However conventional DLTS may lead to erroneous results if there are several closely spaced energy levels or the emission rate has a continuous spectrum. To overcome this difficulty a novel method named the multi-exponential analysis of DLTS by CONTIN (MEDLTS by CONTIN) is proposed. This method analyzes the emission rate to have a finite continuous spectrum S(λ) which appears in the transient junction capacitance C(t)=, by using the program “CONTIN” developed by Provencher in biophysics. Even if S(λ) includes two peaks at λ1 and λ2, those peaks can be distinguished for λ2/ λ1>2. As an example of the application of this method, deep levels in Si:Au were experimentally investigated. According to the three dimensional S(λ)-T2/λ-1/T representation, the single peak in the conventional DLTS was clarified to consist of two adjacent levels with activation energies and capture cross sections EB1=0.51eV, σB1=4.0×10−15cm2 and EB2=0.47eV, σB2=1.1×10−15cm2. With the assumption of the finite continuous spectrum S(λ) for the emission rate, MEDLTS by CONTIN permits one to get much information correctly. MEDLTS by CONTIN is superior to the conventional DLTS because it is a single-temperature scan, multi-exponential analysis instead of the conventional multi-temperature scan, single-exponential analysis.</jats:p
The new metropolitan voices.Glossary of metropolitan terms
No full textThe need for a glossary for the metropolitan discipline emerged from the long experiences of the HEI co-financed Erasmus + Tellme's partners working in the multidisciplinary environment of metropolitan context. A clear set of definitions describing various concepts of the new metropolitan discipline subject is fundamental for accessible communication among the different fields in the academy and with the practitioners. Glossary serves to understand the different perspectives from various fields and topics.
The complexity of the new discipline requires a different perspective in framing the issues and solutions, and the Metropolitan Glossary is a way to begin creating the new conceptual structure of the discipline. Based on the primary needs identified above, the characteristics of the Metropolitan Glossary can be divided into four main categories: linkage between practical values and theoretical principle background, the link between qualitative narrative and quantitative data, flexibility, and accessibility.
Clear communication among various agencies in a metropolitan project is an important issue. The issues and the solutions in the practical context are as valuable as the theoretical knowledge in understanding the principles of the metropolitan structure. However, the time difference in academia and practice create a gap between theory and practice. Often the symptoms of metropolitan issues occur unpredictably, and the decisions need to be made in real-time when the gaps are revealed to reduce the negative impact of the conflict. Even though in some cases, academic knowledge is required in the form of consultancy, often the knowledge is highly specialised and has a limit in addressing the complexity that spans across multiple disciplines. Therefore, it is fundamental to change the way knowledge is being built from the beginning. The Metropolitan Glossary has numerous entry points so that both theoretical and practical knowledge is accumulating in the form of keywords. The discussion goes beyond the individual terms and focuses on the relationship amongst words composing the fundamental concepts in the metropolitan discipline.
It is an open-ended collection of vocabulary brought and discussed by experts of various fields
L'era metropolitana. Gamme estese di desideri e cambi frequenti di stili di vita
No full textLa modernizzazione, legata alle possibilità offerte dalle nuove tecnologie, determina una manomissione fisica del territorio e una nuova bigness, che significa un nuovo modo della offerta e degli scambi. I luoghi dell’abitare, della produzione, dell’incontro e della transizione o passaggio mutano già all’interno del paradigma urbano, che cambia di scala e si modifica, e non come parrebbe, localmente, dove pure si trasformano l’ordine della cultura locale e le strutture mentali. Tutto il problema della città che va alla scala della metropoli non è un problema di reti e di pura accessibilità, ma di contenitori condensatori di funzioni urbane rare, che inducono la nuova scala nel contesto locale. Non solo, quindi, è necessaria una invenzione morfologica, ma anche funzionale connessa profondamente con il controllo delle esternalità. Un attento monitoraggio dell’obsolescenza della qualità della vita dei cittadini consente inoltre di comprendere se gli enti urbani, alla nuova scala, si collocheranno nel tessuto o andranno incontro ad una nuova definizione di assetto. Il problema è la progettazione architettonica e urbana e l’identificazione dei segni che consentano ad entrambe le cittadinanze di passare di scala e dei simboli o tracce idiomatiche che riuniscano, nella odierna condizione multiculturale, lo spazio fisico, sociale e immaginario atteso/progettato. Nell’era dell’informazione, quello dello spazio dei flussi, per la costruzione della nuova dimensione della città e in nome di una “utopia tecnologica”, le reti infrastrutturali sovrapponendosi all’universo naturale,agricolo e urbano storico ne hanno disfatto e a volte cancellato i quadri topografici. Per il progetto si presenta fortissimo un problema di scala, dal momento che in questo contesto, fondamentalmente multiscala, abbiamo una coesistenza discontinua di strutture spaziali in diverse condizioni: un fuori scala dell’universo tecnologico, che richiede una risposta alla nuova relazione che si instaura tra i tracciati urbani presenti sul territorio rispetto al rapporto tipologico/morfologico delle reti odierne; le misure antropometriche, che valgono alla scala dell’architettura e a quella agricola; le misure fuori scala dell’universo pre- storico, fuori scala anch’esse, perché legate ad un tempo che è oltre e prima che si instaurasse un’organizzazione antropica e tecnica. È un problema di discontinuità, che è nei fatti, perché il nesso tecnologico costituito per stabilire la possibilità di una accessibilità efficace e di una programmazione del tempo attraverso l’efficienza, esige una decisione precisa su quali relazioni e a quale scala vadano intensificate: quella del suolo originale, storico, metropolitano fino alla scala delle città del mondo. I passaggi dall’una all’altra di queste scale sono mediati da forme di introduzione costituiti dai grandi contenitori multiscala e multifunzionali, condensatori di funzioni urbane rare. Nella prospettiva delle grandi interferenze: ferroviaria, autostradale di terra e di mare, aeroportuale, questi punti emergenti,- “pôle e quartier d’échange “ (Moutard, Arep)- sono i referenti delle relazioni di contesto a scale superiori, in una dimensione metropolitana nella quale il riferimento al “contesto” non è più assoluto. Questi poli, contemporaneamente, appartengono e introducono alla scala del quartiere, della città e della metropoli e in rari punti - aerostazioni e stazioni dell’Alta velocità – alla rete mondiale. Sono punti multiscala, multimappa e dunque, richiamano l’attenzione sullo studio di una logica degli intrecci fra tracciati esistenti e nodi intermodali e sulla deformazione fisica degli spazi praticabili dalla dimensione tecnica per accedere agli spazi locali, nel confronto con le forme colte della pratica dello spazio: com’è possibile rendere sensibile l’universo tecnico ai suoli naturali? Infatti, ogni polo rappresenta un ingresso, costruito per accedere ai suoli storici e naturali, elemento di un modello di morfotipo, nato in conformità ad una riconoscibilità geografica. Il primo tema da affrontare è quindi la relazione tra morfologia geografica e morfologia urbana, tracce di fondazione e suoli artificiali
The STAR Heavy Flavor Tracker and Upgrade Plan
No full textThe Heavy Flavor Tracker (HFT) of the STAR experiment at RHIC is the first application of the state-of-the-art thin Monolithic Active Pixel Sensors (MAPS) technology in a collider environment. The HFT is composed of two silicon PiXeL detector (PXL) layers, an Intermediate Silicon Tracker (IST) and a Silicon Strip Detector (SSD). It greatly improves the impact parameter resolution of STAR tracking and enables reconstruction of secondary decay vertices of open heavy hadrons in heavy ion collisions, providing unique probes for studying the Quark-Gluon Plasma. In these proceedings we discuss the HFT hardware design, and current detector status and performance. The HFT was successfully commissioned during the 2014 RHIC run, taking data in Au+Au collisions at 200 GeV. The HFT performance during this run matches the expected performance, most significantly for track pointing resolution. Preliminary results have been obtained from 2014 Au+Au data analyses, demonstrating the capabilities of open charm hadron reconstruction with the HFT. Modifications to HFT subsystems have been made to improve its performance in the 2015 run in p+p, p+Au and p+Al collisions at sNN=200 GeV . In order to further improve such capabilities to measure bottom quark hadrons at RHIC energies, a faster heavy flavor tracker (HFT+) is needed to collect data at higher luminosity with good efficiency. The proposed HFT+ will be equipped with new generation of MAPS sensors with a much shorter integration time ( ≤40μs ) and possibly extend the current PXL detector acceptance with minimal modification to the original mechanical and air cooling infrastructure. Requirements for the upgraded HFT+ detector and expected performance are also presented in these proceedings
The MAPS-based ITS Upgrade for ALICE
No full textThe Inner Tracking System (ITS) Upgrade for the ALICE experiment at LHC is the first large-area (10~m) silicon vertex detector based on the CMOS Monolithic Active Pixel Sensor (MAPS) technology, which combines sensitive volume and front-end readout logic in the same piece of silicon. This technology allows a reduced material budget (target value of 0.3\% on the innermost layers) thanks to the thin sensors (50-100~m) and limited need of cooling, in combination with light-material interconnection circuits and support structures. The small pixel pitch (30~m), the location of the layers (7 cylindrical layers with radii ranging from 2.3~cm to 39.3~cm from the beam interaction line), and the limited material budget will provide the ALICE experiment with extremely precise tracking resolution. The high-rate readout capabilities will also enable ALICE to collect a large data sample at the 50~kHz Pb--Pb collision rate expected in the LHC Run~3. The new ITS, now assembled at the surface, is currently undergoing an exhaustive pre-commissioning phase with standalone calibration and cosmic ray data-taking, which will be completed by April 2020 before the installation in the ALICE detector. Experience gained from the construction and the pre-commissioning phase, and plans for the installation and preparation for the data-taking in ALICE will be presented in this paper. The role played by the new ITS within the development path of the MAPS technology for future applications will also be briefly discussed.The Inner Tracking System (ITS) Upgrade for the ALICE experiment at LHC is the first large-area (10 m) silicon vertex detector based on the CMOS Monolithic Active Pixel Sensor (MAPS) technology, which combines sensitive volume and front-end readout logic in the same piece of silicon. This technology allows a reduced material budget (target value of 0.3\% on the innermost layers) thanks to the thin sensors (50-100 m) and limited need of cooling, in combination with light-material interconnection circuits and support structures. The small pixel pitch (30 m), the location of the layers (7 cylindrical layers with radii ranging from 2.3 cm to 39.3 cm from the beam interaction line), and the limited material budget will provide the ALICE experiment with extremely precise tracking resolution. The high-rate readout capabilities will also enable ALICE to collect a large data sample at the 50 kHz Pb--Pb collision rate expected in the LHC Run 3.The new ITS, now assembled at the surface, is currently undergoing an exhaustive pre-commissioning phase with standalone calibration and cosmic ray data-taking, which will be completed by April 2020 before the installation in the ALICE detector. Experience gained from the construction and the pre-commissioning phase, and plans for the installation and preparation for the data-taking in ALICE will be presented in this paper.The role played by the new ITS within the development path of the MAPS technology for future applications will also be briefly discussed
III. Articles et notes
No full textContin Raphaël. III. Articles et notes . In: Revue juridique de l'Ouest, 1989-1. p. 170
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