Publications (11)0 Total impact
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Article: On the sensitivity of the HAWC observatory to gamma-ray bursts
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ABSTRACT: We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn could help to understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to which GRBs accelerate particles.08/2011; -
Article: The RICH detector of the AMS-02 experiment: status and physics prospects
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ABSTRACT: The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be installed on the International Space Station (ISS) for at least 3 years, is a detector designed to measure charged cosmic ray spectra with energies up to the TeV region and with high energy photon detection capability up to a few hundred GeV. It is equipped with several subsystems, one of which is a proximity focusing RICH detector with a dual radiator (aerogel+NaF) that provides reliable measurements for particle velocity and charge. The assembly and testing of the AMS RICH is currently being finished and the full AMS detector is expected to be ready by the end of 2008. The RICH detector of AMS-02 is presented. Physics prospects are briefly discussed.02/2008; -
Article: The AMS-RICH velocity and charge reconstruction
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ABSTRACT: The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored. The algorithms developed to fulfill these requirements are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed.10/2007; -
Article: The use of cosmic muons in detecting heterogeneities in large volumes
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ABSTRACT: The muon intensity attenuation method to detect heterogeneities in large matter volumes is analyzed. Approximate analytical expressions to estimate the collection time and the signal to noise ratio, are proposed and validated by Monte Carlo simulations. Important parameters, including point spread function and coordinate reconstruction uncertainty are also estimated using Monte Carlo simulations.10/2007; -
Article: The Ring Imaging Cherenkov detector (RICH) of the AMS experiment
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ABSTRACT: The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and velocity of the charged cosmic particles. A RICH prototype consisting of 96 photomultiplier units, including a piece of the conical reflector, was built and its performance evaluated with ion beam data. Preliminary results of the in-beam tests performed with ion fragments resulting from collisions of a 158 GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported. The collected data included tests to the final front-end electronics and to different aerogel radiators. Cherenkov rings for a large range of charged nuclei and with reflected photons were observed. The data analysis confirms the design goals. Charge separation up to Fe and velocity resolution of the order of 0.1% for singly charged particles are obtained.05/2006; -
Conference Proceeding: The AMS-RICH prototype: test beam results [alpha magnetic spectrometer-ring imaging Cerenkov counter]
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ABSTRACT: We report on the performance of the (alpha magnetic spectrometer) AMS Cerenkov counter prototype under a beam of light ions at CERN SPS. In particular the efficiency to determine the velocity and the charge of the incoming particles is studied for different radiators.Instrumentation and Measurement Technology Conference, 2004. IMTC 04. Proceedings of the 21st IEEE; 06/2004 -
Article: The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -
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ABSTRACT: A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.07/2003; -
Article: Characterization study of silica aerogel for Cherenkov imaging
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ABSTRACT: Different methods to measure the characteristics of silica aerogel tiles used as Cherenkov radiator in the CREAM and AMS experiments have been investigated to optimize the detector performances. The measurement accuracy dictated by the physics objectives on the velocity and charge resolutions set stringent requirements on the aerogel refractive index determination, namely Δn∼1.5×10−4 and Δn∼5×10−4 for the AMS and CREAM imagers, respectively. The matching of such accuracies for this material turned out to be a metrological challenge, and finally led to a full R&D program, to develop an appropriate characterization procedure. Preliminary studies performed with a standard refractive index measurement technique (laser beam deviation by a prism) have revealed a significant systematic index nonuniformity for the AMS tiles at a level (10−3), not acceptable considering the aimed accuracy. These large variations were confirmed in a beam test. A second method, mapping the transverse index gradient by deflection of a laser beam entering normally to the tile has then been developed. It is shown that this procedure is suitable to reach the required accuracy, at the price of using both methods combined. The several hundreds of tiles of the radiator plane of the CREAM and AMS Cherenkov imagers were characterized using a simplified procedure, however, appropriate for each case, compromising between the amount of work and the time available. The experimental procedures and set-ups used are described in the text, and the obtained results are reported.Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. -
Article: In-beam tests of the AMS RICH prototype with 20AGeV/c secondary ions
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ABSTRACT: A prototype of the AMS Cherenkov imager (RICH) has been tested by means of a low intensity per nucleon ion beam coming from the fragmentation of a primary beam of Pb ions. Data have been collected for charges 1<Z<∼45 in various beam conditions and using different radiators. The charge Z and velocity β resolution have been of the prototype investigated.Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. -
Article: In-beam tests of the AMS RICH prototype with 20 A GeV/c secondary ions
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Article: Prototype study of the Cherenkov imager of the AMS experiment
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ABSTRACT: The AMS experiment includes a Cherenkov imager for mass and charge identification of charged cosmic rays. A second generation prototype has been constructed and its performances evaluated both with cosmic ray particles and with beam ions. In-beam tests have been performed using secondary nuclei from the fragmentation of per nucleon Pb ions and per nucleon In from the CERN SPS in 2002 and 2003. Partial results are reported. The performances of the prototype for the velocity and the charge measurements have been studied over the range of ion charge Z≲30. A sample of candidate silica aerogel radiators for the flight model of the detector has been tested. The measured velocity resolution of the detector was found to scale with Z-1 as expected, with a value σ(β)/β≈0.7–110-3 for singly charged particles and an asymptotic limit in Z of 0.4–0.6×10-4. The measured charge resolution obtained for the n=1.05 aerogel radiator material selected for the flight model of the detector is σ(Z)=0.18 (statistical) ⊕ 0.015 (systematic), ensuring a good charge separation up to the iron element, for the prototype in the reported experimental conditions.Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
Top co-authors
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Institutions
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2006
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University of Maryland, College Park
College Park, MD, USA
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2003
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National Autonomous University of Mexico
- Institute of Physics
Mexico City, The Federal District, Mexico
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