1,355,044 research outputs found
Machine R&D towards a Neutrino Factory
No full textThe main R&D items toward construction of a Neutrino Factory are presented, with emphasis on a Muon Ionization Cooling Experiment
Measurements of hadron production cross sections and secondary particle yields in the energy range 2-15 GeV using neutrino beam targets
No full textThe HARP experiment at CERN is performing extensive measurements ofhadron production cross sections and secondary particle yieldsin the energy range 2-15 GeV over the full solid angle, usinga large set of cryogenic and solid targets.Hadron production in this kinematic region is a relevant ingredient inseveral branches of neutrino physics, such as characterisation of neutrinobeams, precise prediction of atmospheric neutrino fluxes, andquantification of pion production and capture for neutrino factory design.An overall precision of few percent is required from the experimentto reach the final aim.The HARP experimental layout comprises two spectrometers to perform momentummeasurement of the secondaries produced in the target.The so called large-angle spectrometer is housing the target and a timeprojection chamber, while the forward spectrometer is equipped with a setof drift chambers and a large-aperture dipole magnet.The time projection chamber allows for track momentum measurementbelow 1 GeV/c at large-angle (including backward-going) tracks.High-momentum small-angle particles passing through the dipolemagnet are measured by the drift chambers.The track momentum reconstruction in the spectrometers is complementedby a set of particle identification detectors (threshold Cerenkov counter,time-of-flight, electromagnetic calorimeter etc.) that allow forparticle type discrimination with some redundancy.About 30 TB of data corresponding to 400 millions of events have beensuccessfully collected during the two years of experiment.First measurements of hadron production cross sections in the forward region(up to about 300 mrad), using the MiniBooNE and K2K replica targetsand a proton beam of respectively 8.9 and 12.9 GeV/c, will be reported.This is an appealing physics case, given the immediate interest for thoseexperiments and for the neutrino community. A preliminary analysis in thelarge angle region on elastic scattering events produced with the cryogenichydrogen target at 3 GeV/c beam momentum will also be presented
A new anti-neutrino detection technique based on positronium tagging with plastic scintillators
No full textThe main signature for anti-neutrino detection in reactor and geo-neutrino experiments based on scintillators is provided by the space-time coincidence of positron and neutron produced in the Inverse Beta Decay reaction. Such a signature strongly suppresses backgrounds and allows for measurements performed underground with a relatively high signal-to-background ratio. In an aboveground environment, however, the twofold coincidence technique is not sufficient to efficiently reject the high background rate induced by cosmogenic events. Enhancing the positron-neutron twofold coincidence efficiency may pave the way to future aboveground detectors for reactor monitoring. We propose a new detection scheme based on a threefold coincidence, among the positron ionization, the ortho-positronium (o-Ps) decay, and the neutron capture, in a sandwich detector with alternated layers of plastic scintillator and aerogel powder. We present the results of a set of dedicated measurements on the achievable light yield and on the o-Ps formation and lifetime. The efficiencies for signal detection and background rejection of a preliminary detector design are also discussed
Results from the 2003 beam test of a MDT BIL chamber : systematic uncertainties on the TDC spectrum parameters and on the space-time relation
No full textThe latest version of MDT front-end electronics, which provides information about the collected charge through a Wilkinson ADC, has been used at the Roma Tre BIL cosmic test site. An analysis of the data collected with this electronics is presented. A method to improve the spatial resolution of MDT chambers using the ADC information to correct the time response has been developed. The procedure is based solely on the data from the MDT chamber itself. The results are compared with a simulation of the tube response with the Garfield program
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Preliminary Study of Z+b Production at LHC
No full textThe study of Z boson production in association with a single heavy flavor jet (gQ ¡æZQ(Q = b,c)) can provide for the Higgs boson, when it is produced together with a b quark and decays in the same final states (b.b, ¥ó+ ¥ó., ¥ì+ ¥ì.). The expected statistics and purity of the event sample that could be selected in the data are evaluated considering two different This paper presents a preliminary investigation of the potential to study the channel Z+b. jet with the Z ¡æ ¥ì¥ìat LHC. methods for the b tagging. The analysis has been performed, first, with a fast simulation of the ATLAS detector, and then, using the full simulation and the complete offline reconstruction algorithms in the official ATLAS software framework
Charge-dependent corrections to the time response of ATLAS muon chambers
No full textMonitored Drift Tubes (MDT), filled with a mixture of Ar-CO2 at 3 bar pressure, are used as tracking devices for the ATLAS muon spectrometer at the Large Hadron Collider. MDT chambers were tested at the Roma Tre cosmic test site with the final version of front-end electronics, which provides information about the collected charge through a Wilkinson ADC. We present an analysis of the signal and timing characteristics in cosmic ray events, and of charge-dependent time response of the MDTs. A method to improve the spatial resolution of MDT chambers using the ADC information to correct the time response was developed. The procedure is based solely on the data from the MDT chamber itself. The results are compared with a simulation of the tube response with the Garfield program. (C) 2004 Elsevier B.V. All rights reserved
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Apparato per la valutazione della rigidità dinamica con il metodo dell'impatto
No full textLa conoscenza della rigidità dinamica dei materiali utilizzati come elemento di disaccoppiamento nei pavimenti galleggianti permette la valutazione dell’incremento per l’isolamento al rumore di calpestio ottenibile. Questo lavoro propone i principi progettuali di un apparato a basso costo che permetta la determinazione dei principali parametri caratterizzanti i materiali resilienti comunemente utilizzati in edilizia; tale macchina potrà essere impiegata sia in laboratorio, per catalogare materiali diversi, che in ambito industriale per il controllo delle caratteristiche dei prodotti. Il sistema si basa sulla sollecitazione dinamica di un provino mediante una forzante impulsiva. Mediante misure accelerometriche, si ricavano quindi i principali parametri di interesse (fattore di smorzamento, frequenza di risonanza della vibrazione verticale fondamentale, la rigidità dinamica). Per la progettazione dell’apparato sono state seguite le indicazioni delle norme UNI EN 29052-1, UNI EN 29053, ISO 7626-1, ISO 7626-2 e ISO 7626-5
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