Showing papers by "Cristina Riccardi published in 2006"
01 Jan 2006
251 citations
TL;DR: In this paper, surface modification of poly(ethylene terephthalate) (PET) fabrics induced by air radiofrequency (RF) plasma treatment has been investigated systematically as a function of plasma device parameters, to identify the plasma polymer surface interactions prevailing under different operating conditions and leading to an increased color depth upon dyeing.
102 citations
01 Aug 2006
TL;DR: In this paper, the formation of highly reactive compounds in the gas mixture during Resistive Plate Chambers (RPCs) operation at the CERN Gamma Irradiation Facility (GIF) is studied.
Abstract: The formation of highly reactive compounds in the gas mixture during Resistive Plate Chambers (RPCs) operation at the CERN Gamma Irradiation Facility (GIF) is studied. Results from two different types of chambers are discussed: 50 × 50 cm 2 RPC prototypes and two final CMS-RB1 chambers. The RB1 detectors were also connected to a closed loop gas system. Gas composition, possible additional impurities as well as fluoride ions have been monitored in different gamma irradiation conditions both in open and closed loop mode. The chemical composition of the RPC electrode surface has also been analyzed using an electron microscope equipped with an EDS/X-ray.
41 citations
University of California, Davis1, CINVESTAV2, University of Colorado Boulder3, Fermilab4, Universidad de Guanajuato5, University of Illinois at Urbana–Champaign6, Indiana University7, Korea University8, Kyungpook National University9, University of Milan10, University of North Carolina at Chapel Hill11, Pontifical Catholic University of Rio de Janeiro12, University of Puerto Rico at Mayagüez13, University of South Carolina14, University of Tennessee15, Vanderbilt University16, University of Wisconsin-Madison17
TL;DR: In this article, a measurement of the weak decayasymmetry parameter α Λ c in the FOCUS (E831) experiment at Fermilab is presented.
32 citations
University of California, Davis1, CINVESTAV2, University of Colorado Boulder3, Fermilab4, Universidad de Guanajuato5, University of Illinois at Urbana–Champaign6, Indiana University7, Korea University8, Kyungpook National University9, University of Milan10, University of North Carolina at Chapel Hill11, University of Puerto Rico at Mayagüez12, University of South Carolina13, University of Tennessee14, Vanderbilt University15, University of Wisconsin-Madison16
TL;DR: In this article, the first measurements of the helicity basis form factor free from the assumption of spectroscopic pole dominance were obtained from a large sample of D + → K − π + μ + ν decays collected by the FOCUS photoproduction experiment at Fermilab.
13 citations
University of California, Davis1, CINVESTAV2, University of Colorado Boulder3, Fermilab4, Universidad de Guanajuato5, University of Illinois at Urbana–Champaign6, Indiana University7, Korea University8, Kyungpook National University9, University of Milan10, University of North Carolina at Chapel Hill11, Pontifical Catholic University of Rio de Janeiro12, University of Puerto Rico at Mayagüez13, University of South Carolina14, University of Tennessee15, Vanderbilt University16, University of Wisconsin-Madison17
TL;DR: In this article, a search for a pentaquark decaying strongly to Ξ − π − in γN collisions at a center-of-mass energy up to 25 GeV / c 2 was presented.
13 citations
01 May 2006
TL;DR: In this paper, a low cost gas-based charged particle detector, the Resistive Plate Counter (RPC) intensively used in fixed target and collider high energy experiments, is proposed as basic detector for Positron Emission Tomography.
Abstract: A low cost gas-based charged particle detector, the Resistive Plate Counter (RPC) intensively used in fixed target and collider high energy experiments, is proposed as basic detector for Positron Emission Tomography. The performance of RPCs in terms of intrinsic space and time resolution and electronic pulse height response, makes it possible to transform standard RPCs into photon detectors and therefore to compensate for the photon sensitivity of scintillating crystals, when the efficiency of the complex crystal + photomultiplier is turned into standard quantum efficiency (q.e). Prototype multigap glass RPCs were developed which optimize γ detection efficiency and thus might substitute the traditional scintillators setups.
11 citations
Posted Content•
TL;DR: The Resistive Plate Chambers (RPC) detector at the LHC proton collider (CERN) will employ an online gas analysis and monitoring system of the freon-based gas mixture used as discussed by the authors.
Abstract: The Resistive Plate Chambers (RPC) detector of the CMS experiment at the LHC proton collider (CERN, Switzerland) will employ an online gas analysis and monitoring system of the freon-based gas mixture used. We give an overview of the CMS RPC gas system, describe the project parameters and first results on gas-chromatograph analysis. Finally, we report on preliminary results for a set of monitor RPC.
10 citations
DOI•
08 Nov 2006TL;DR: The RPC Balcony Collector (RBC) as discussed by the authors is a new board for the resistive plate chamber of the magnet test-Cosmic challenge (MCTC) detector.
Abstract: In the CMS experiment, sub-detectors may send special trigger signals, called “Technical Triggers”, for purposes like test and calibration. The Resistive Plate Chambers are part of the Muon Trigger System of the experiment, but might also produce a cosmic muon trigger to be used during the commissioning of the detectors, the CMS Magnet Test-Cosmic Challenge and the later running of CMS. The proposed implementation is based on the development of a new board, the RPC Balcony Collector (RBC); the test results on prototypes and their performance during the recent CMS Cosmic Challenge are presented.
10 citations
TL;DR: In this article, the characteristics of a plasma reactor for the promotion of chemical reactions aimed to hydrogen reforming from gaseous hydrocarbons were studied, where a plasma torch-like electrode configuration was powered by a limited current, high voltage DC source.
Abstract: We have studied the characteristics of a plasma reactor for the promotion of chemical reactions aimed to hydrogen reforming from gaseous hydrocarbons. A plasma torch-like electrode configuration was powered by a limited current, high voltage DC source. Using as process gas an argon/methane mixture at atmospheric pressure, we have produced an intermittent spark discharge which has been investigated at different operating parameters. Experimental information on the discharge have been used to perform a numerical simulation of the plasma chemical kinetics. The evolution of the gas-phase composition during and after the interaction in the discharge region was calculated under different operating conditions. The results have been used to predict the hydrogen production yield in the experiments and to study the role played by the different discharge parameters in order to determine the optimal interaction between plasma and gas mixture.
9 citations
TL;DR: In this paper, the boundary condition of the Blaamann device was changed by applying a dc bias on a limiter extended around the entire poloidal circumference of the column.
Abstract: We report results from experiments performed to study how a change in boundary conditions affects the plasma state in the toroidal geometry of the Blaamann device in Tromso. The boundary condition was changed by applying a dc bias on a limiter extended around the entire poloidal circumference of the plasma column. Two distinctly different plasma potential states were found. One state was associated with a bias at or negative with respect to the floating potential of the limiter, and a small ion-saturation current. The other state was associated with a positive bias with respect to the floating potential, near or in the electron saturation regime of the limiter. In the latter case the potential minimum in the middle of the cross-section was significantly less negative than in the case of ion-saturation current to the limiter. On the other hand, the grounded limiter provided the best confinement properties, for which the density maximum was significantly higher than for both more positive and more negative biases. This state also had the lowest fluctuation levels, and near zero poloidal velocities close to the boundaries, as well as the smallest radial, anomalous particle transport.
TL;DR: A simple model for simulating cross correlations of a many-assets market reproduces the empirically observed fat tails in the distribution function of logarithmic price variations and leads to additional cross correlations between the time series, in better agreement with the real market behavior.
Abstract: A simple model for simulating cross correlations of a many-assets market is discussed. Correlations between assets are initially considered within the context of the well-known one-factor model, in which a driving term common to all stocks is present. The results are compared to those of real market data corresponding to a set of 445 stocks taken from the Standard and Poors 500 index. The model is further extended by introducing a stochastic volatility within each time series using an autoregressive scheme. This artificial market reproduces the empirically observed fat tails in the distribution function of logarithmic price variations and, more important, leads to additional cross correlations between the time series, in better agreement with the real market behavior.
University of California, Davis1, CINVESTAV2, University of Colorado Boulder3, Fermilab4, Universidad de Guanajuato5, University of Illinois at Urbana–Champaign6, Indiana University7, Korea University8, Kyungpook National University9, University of Milan10, University of North Carolina at Chapel Hill11, Pontifical Catholic University of Rio de Janeiro12, University of Puerto Rico at Mayagüez13, University of South Carolina14, University of Tennessee15, Vanderbilt University16, University of Wisconsin-Madison17
TL;DR: In this paper, a new measurement of the charm semileptonic branching ratio was presented using data collected by the FOCUS experiment at Fermilab, and the new measurement was shown to be 0.041 ± 0.004.
01 Aug 2006
TL;DR: In this article, an RPC-based system was employed for the first level trigger of the CMS muon first level triggers and the acceptance percentage for the second part of the single gaps and double gaps production.
Abstract: An RPC based system will be employed for the CMS muon first level trigger. Severe quality controls and certification have been established all along the entire production chain. Procedures are briefly described and results for the acceptance percentage are given for the second part of the single gaps and double gaps production. Summary results are also reported for the full sets of tested chambers.
TL;DR: In this paper, a characterization of the device-pumping behavior of a vacuum reactor for plasma treatment of materials at low pressure is presented, and the analysis of the pumpdown curves measured both in the viscous and in the molecular regimes is made to study the outgassing flowrates of several leather materials.