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Sökning: WFRF:(Grishantseva L. A.)

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1.
  • Adriani, O., et al. (författare)
  • Measurement of the flux of primary cosmic ray antiprotons with energies of 60 MeV to 350 GeV in the PAMELA experiment
  • 2013
  • Ingår i: JETP Letters. - 0021-3640 .- 1090-6487. ; 96:10, s. 621-627
  • Tidskriftsartikel (refereegranskat)abstract
    • It is interesting to measure the antiproton galactic component in cosmic rays in order to study the mechanisms by which particles and antiparticles are generated and propagate in the Galaxy and to search for new sources of, e.g., annihilation or decay of dark matter hypothetical particles. The antiproton spectrum and the ratio of the fluxes of primary cosmic ray antiprotons to protons with energies of 60 MeV to 350 GeV found from the data obtained from June 2006 to January 2010 in the PAMELA experiment are presented. The usage of the advanced data processing method based on the data classification mathematical model made it possible to increase statistics and analyze the region of higher energies than in the earlier works.
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2.
  • Bazilevskaya, G. A., et al. (författare)
  • Solar proton events at the end of the 23rd and start of the 24th solar cycle recorded in the PAMELA experiment
  • 2013
  • Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 77:5, s. 493-496
  • Tidskriftsartikel (refereegranskat)abstract
    • The PAMELA magnetic spectrometer was launched into a near-Earth orbit on board the Resurs-DK1 satellite in June 2006; in December 2006, it recorded the last strong solar high-energy particle event of the 23rd solar cycle. A deficit was thereafter observed in solar energetic particle events because of the lengthy solar activity minimum and the weak evolution of the next (24th) solar cycle. As a result, only a few solar events involving protons with energies of more than 100 MeV were recorded between 2010 and 1012. This work presents the preliminary results from measurements of charged particle fluxes in these events, recorded by the Pamela spectrometer.
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3.
  • Mayorov, A. G., et al. (författare)
  • Antiprotons of galactic cosmic radiation in the PAMELA experiment
  • 2013
  • Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 77:5, s. 602-605
  • Tidskriftsartikel (refereegranskat)abstract
    • A method for antiproton selection against a background of electrons, based on a mathematical model of data classification using variations in interparticle interaction in a calorimeter, and a method for excluding events accompanied by scattering in the inner detectors of a tracking system (which result in errors in the measured trajectory's curvature and charge sign) from analysis are discussed in this paper. Antiproton spectra and antiproton/proton flux ratio at energies of 0.06 to 350 GeV with statistics of events surpassing those in [1] are obtained. The results can be used to create models for the generation and distribution of particles in the Galaxy, and for searching and studying the nature of hypothetical dark matter particles.
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4.
  • Adriani, O., et al. (författare)
  • Measurements of quasi-trapped electron and positron fluxes with PAMELA
  • 2009
  • Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 114, s. A12218-
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents precise measurements of the differential energy spectra of quasi-trapped secondary electrons and positrons and their ratio between 80 MeV and 10 GeV in the near-equatorial region (altitudes between 350 km and 600 km). Latitudinal dependences of the spectra are analyzed in detail. The results were obtained from July until November 2006 onboard the Resurs-DK satellite by the PAMELA spectrometer, a general purpose cosmic ray detector system built around a permanent magnet spectrometer and a silicon-tungsten calorimeter.
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5.
  • Adriani, O., et al. (författare)
  • Measurements of cosmic-ray proton and helium spectra with the PAMELA calorimeter
  • 2013
  • Ingår i: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 51:2, s. 219-226
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a new measurement of the cosmic ray proton and helium spectra by the PAMELA experiment performed using the "thin" (in terms of nuclei interactions) sampling electromagnetic calorimeter. The described method, optimized by using Monte Carlo simulation, beam test and experimental data, allows the spectra to be measured up to 10 TeV, thus extending the PAMELA observational range based on the magnetic spectrometer measurement.
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6.
  • De Simone, N., et al. (författare)
  • Latitudinal and radial gradients of galactic cosmic ray protons in the inner heliosphere - PAMELA and Ulysses observations
  • 2011
  • Ingår i: Astrophysics and Space Sciences Transactions (ASTRA). - : Copernicus GmbH. - 1810-6528 .- 1810-6536. ; 7:3, s. 425-434
  • Tidskriftsartikel (refereegranskat)abstract
    • Ulysses, launched on 6 October 1990, was placed in an elliptical, high inclined (80.2°) orbit around the Sun, and was switched off in June 2009. It has been the only spacecraft exploring high-latitude regions of the inner heliosphere. The Kiel Electron Telescope (KET) aboard Ulysses measures electrons from 3 MeV to a few GeV and protons and helium in the energy range from 6 MeV/nucleon to above 2 GeV/nucleon. The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) space borne experiment was launched on 15 June 2006 and is continuously collecting data since then. The apparatus measures electrons, positrons, protons, anti-protons and heavier nuclei from about 100 MeV to several hundreds of GeV. Thus the combination of Ulysses and PAMELA measurements is ideally suited to determine the spatial gradients during the extended minimum of solar cycle 23. For protons in the rigidity interval 1.6-1.8 GV we find a radial gradient of 2.7%/AU and a latitudinal gradient of -0.024%/degree. Although the latitudinal gradient is as expected negative, its value is much smaller than predicted by current particle propagation models. This result is of relevance for the study of propagation parameters in the inner heliosphere.
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7.
  • Adriani, O., et al. (författare)
  • OBSERVATIONS OF THE 2006 DECEMBER 13 AND 14 SOLAR PARTICLE EVENTS IN THE 80 MeV n(-1)-3 GeV n(-1) RANGE FROM SPACE WITH THE PAMELA DETECTOR
  • 2011
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 742:2, s. 102-
  • Tidskriftsartikel (refereegranskat)abstract
    • We present the space spectrometer PAMELA observations of proton and helium fluxes during the 2006 December 13 and 14 solar particle events. This is the first direct measurement of the solar energetic particles in space with a single instrument in the energy range from similar to 80 MeV n(-1) up to similar to 3 GeV n(-1). For the December 13 event, measured energy spectra of solar protons and helium are compared with results obtained by neutron monitors and other detectors. Our measurements show a spectral behavior different from those derived from the neutron monitor network. No satisfactory analytical fitting was found for the energy spectra. During the first hours of the December 13 event, solar energetic particles spectra were close to the exponential form, demonstrating rather significant temporal evolution. Solar He with energy up to 1 GeV n(-1) was recorded on December 13. For the December 14 event, energy of solar protons reached 600 MeV, whereas the maximum energy of He was below 100 MeV n(-1). The spectra were slightly bent in the lower energy range and preserved their form during the second event. Differences in the particle flux appearance and temporal evolution of these two events may argue for special conditions leading to the acceleration of solar particles up to relativistic energies.
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8.
  • Adriani, O., et al. (författare)
  • PAMELA Measurements of Cosmic-Ray Proton and Helium Spectra
  • 2011
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 332:6025, s. 69-72
  • Tidskriftsartikel (refereegranskat)abstract
    • Protons and helium nuclei are the most abundant components of the cosmic radiation. Precise measurements of their fluxes are needed to understand the acceleration and subsequent propagation of cosmic rays in our Galaxy. We report precision measurements of the proton and helium spectra in the rigidity range 1 gigavolt to 1.2 teravolts performed by the satellite-borne experiment PAMELA (payload for antimatter matter exploration and light-nuclei astrophysics). We find that the spectral shapes of these two species are different and cannot be described well by a single power law. These data challenge the current paradigm of cosmic-ray acceleration in supernova remnants followed by diffusive propagation in the Galaxy. More complex processes of acceleration and propagation of cosmic rays are required to explain the spectral structures observed in our data.
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9.
  • Adriani, O., et al. (författare)
  • PAMELA Results on the Cosmic-Ray Antiproton Flux from 60 MeV to 180 GeV in Kinetic Energy
  • 2010
  • Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 105:12, s. 121101-
  • Tidskriftsartikel (refereegranskat)abstract
    • The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray antiproton flux and the antiproton-to-proton flux ratio which extends previously published measurements down to 60 MeV and up to 180 GeV in kinetic energy. During 850 days of data acquisition approximately 1500 antiprotons were observed. The measurements are consistent with purely secondary production of antiprotons in the Galaxy. More precise secondary production models are required for a complete interpretation of the results.
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10.
  • De Simone, N., et al. (författare)
  • PAMELA : Measurements of matter and antimatter in space
  • 2011
  • Ingår i: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics. - 1124-1896 .- 1826-9885. ; 34:3, s. 79-87
  • Tidskriftsartikel (refereegranskat)abstract
    • On the 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail counter scintillator and a neutron detector. The combination of these devices allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV-100's GeV) with high statistics. The primary scientific goal is the measurement of the antiproton and positron energy spectra in order to search for exotic sources, such as dark matter particle annihilations. PAMELA is also searching for primordial antinuclei (antihelium), and testing cosmic-ray propagation models through precise measurements of the antiparticle energy spectrum and precision studies of light nuclei and their isotopes. Moreover, PAMELA investigates phenomena connected with solar and earth physics. The main results and updated data will be presented.
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11.
  • Giaccari, U., et al. (författare)
  • Anisotropy studies in the cosmic ray proton flux with the PAMELA experiment
  • 2013
  • Ingår i: Proceedings of the 9th workshop on Science with the New Generation of High Energy Gamma-ray Experiments: From high energy gamma sources to cosmic rays, one century after their discovery. - : Elsevier. ; , s. 123-128
  • Konferensbidrag (refereegranskat)abstract
    • Using data taken by the Pamela experiment during 5 years of operation we studied the anisotropy in the arrival direction distribution of cosmic ray protons with rigidity above 40 GV. In this survey we used two different and independent techniques to investigate the large and medium anisotropy patterns in the proton spectrum. With both methods the observed distribution of arrival directions is consistent with the isotropic expectation and no significant evidence of strong anisotropies has been observed.
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12.
  • Menn, W., et al. (författare)
  • The PAMELA space experiment
  • 2013
  • Ingår i: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 51:2, s. 209-218
  • Tidskriftsartikel (refereegranskat)abstract
    • On the 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The apparatus is comprised of a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail counter scintillator and a neutron detector. The combination of these devices allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV to 100's GeV) with high statistics. The primary scientific goal is the measurement of the antiproton and positron energy spectra in order to search for exotic sources, such as dark matter particle annihilations. PAMELA is also searching for primordial antinuclei (anti-helium), and testing cosmic-ray propagation models through precise measurements of the antiparticle energy spectrum and precision studies of light nuclei and their isotopes. Moreover, PAMELA is investigating phenomena connected with solar and earth physics. After 4 years of operation in flight, PAMELA is now delivering coherent results about spectra and chemical composition of the charged cosmic radiation, allowing scenarios of production and propagation of cosmic rays to be fully established and understood.
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13.
  • Mocchiutti, E., et al. (författare)
  • Results from PAMELA
  • 2011
  • Ingår i: NUCL PHYS B-PROC SUP. - : Elsevier BV. ; , s. 243-248
  • Konferensbidrag (refereegranskat)abstract
    • The PAMELA satellite experiment was launched into low earth orbit on June 15(th) 2006. The combination of a permanent magnet silicon strip spectrometer and a silicon-tungsten imaging calorimeter allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV - several hundred GeV). A primary scientific goal is to search for dark matter particle annihilation by measuring the energy spectra of cosmic ray antiparticles. Latest results from the PAMELA experiment are presented with a particular focus on cosmic ray antiprotons and positrons.
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14.
  • Adriani, O., et al. (författare)
  • A statistical procedure for the identification of positrons in the PAMELA experiment
  • 2010
  • Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 34:1, s. 1-11
  • Tidskriftsartikel (refereegranskat)abstract
    • The PAMELA satellite experiment has measured the cosmic-ray positron fraction between 1.5 GeV and 100 GeV. The need to reliably discriminate between the positron signal and proton background has required the development of an ad hoc analysis procedure. In this paper, a method for positron identification is described and its stability and capability to yield a correct background estimate is shown. The analysis includes new experimental data, the application of three different fitting techniques for the background sample and an estimate of systematic uncertainties due to possible inaccuracies in the background selection. The new experimental results confirm both solar modulation effects on cosmic-rays with low rigidities and an anomalous positron abundance above 10 GeV. (c) 2010 Elsevier B.V. All rights reserved.
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15.
  • Adriani, O., et al. (författare)
  • Cosmic-Ray Electron Flux Measured by the PAMELA Experiment between 1 and 625 GeV
  • 2011
  • Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 106:20, s. 201101-
  • Tidskriftsartikel (refereegranskat)abstract
    • Precision measurements of the electron component in the cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy. Here we present new results regarding negatively charged electrons between 1 and 625 GeV performed by the satellite-borne experiment PAMELA. This is the first time that cosmic-ray e(-) have been identified above 50 GeV. The electron spectrum can be described with a single power-law energy dependence with spectral index -3.18 +/- 0.05 above the energy region influenced by the solar wind (> 30 GeV). No significant spectral features are observed and the data can be interpreted in terms of conventional diffusive propagation models. However, the data are also consistent with models including new cosmic-ray sources that could explain the rise in the positron fraction.
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16.
  • Adriani, O., et al. (författare)
  • Secondary electron and positron fluxes in the near-Earth space observed in the ARINA and PAMELA experiments
  • 2009
  • Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 73:3, s. 364-366
  • Tidskriftsartikel (refereegranskat)abstract
    • Secondary electron and positron fluxes in the energy range from 3 MeV to 7 GeV were measured with the ARINA and PAMELA spectrometers onboard the Resurs-DK satellite launched on June 15, 2006 into an elliptical orbit with an inclination of 70.4° and an altitude of 350-600 km. It is shown that positrons dominate over electrons by a factor of up to 4-5 in the geomagnetic equator region (L < 1.2 and B > 0.25).
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17.
  • Bruno, A., et al. (författare)
  • First detection of geomagnetically trapped antiprotons by the PAMELA experiment
  • 2011
  • Ingår i: Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011. - : Institute of High Energy Physics. ; , s. 86-89
  • Konferensbidrag (refereegranskat)abstract
    • We present the measurement of geomagnetically trapped antiprotons in the South Atlantic Anomaly performed by the PAMELA satellite-bourne experiment. The existence of an antiproton radiation belt, predicted by several models as the product of cosmic ray interactions with the residual terrestrial atmosphere, is evidenced for the first time. PAMELA measured the antiproton spectrum in the kinetic energy range between 60 and 750 MeV, reporting a trapped antiproton flux which exceeds by about 3 orders of magnitude the interplanetary cosmic ray antiproton flux. An estimation of the mean under-cutoff antiproton flux outside radiation belts has been also provided.
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18.
  • Bruno, A., et al. (författare)
  • Precise cosmic rays measurements with PAMELA
  • 2013
  • Ingår i: Acta Polytechnica. - 1210-2709. ; 53:Suppl.1, s. 712-717
  • Tidskriftsartikel (refereegranskat)abstract
    • The PAMELA experiment was launched on board the Resurs-DK1 satellite on June 15th 2006. The apparatus was designed to conduct precision studies of charged cosmic radiation over a wide energy range, from tens of MeV up to several hundred GeV, with unprecedented statistics. In five years of continuous data taking in space, PAMELA accurately measured the energy spectra of cosmic ray antiprotons and positrons, as well as protons, electrons and light nuclei, sometimes providing data in unexplored energetic regions. These important results have shed new light in several astrophysical fields like: an indirect search for Dark Matter, a search for cosmological antimatter (anti-Helium), and the validation of acceleration, transport and secondary production models of cosmic rays in the Galaxy. Some of the most important items of Solar and Magnetospheric physics were also investigated. Here we present the most recent results obtained by the PAMELA experiment.
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19.
  • Bruno, A., et al. (författare)
  • Trapped protons in SAA measured by the PAMELA experiment
  • 2011
  • Ingår i: Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011. - : Institute of High Energy Physics. ; , s. 82-85
  • Konferensbidrag (refereegranskat)abstract
    • An accurate measurement of under cutoff proton fluxes in the energy range 60 MeV ÷ 3 GeV has been performed by the PAMELA satellite-borne experiment. Thanks to the high identification performances and to the semipolar and elliptic satellite orbit, PAMELA is able to provide information about spectra and composition of particles in different regions of the magnetosphere. Here we present the measurement of the geomagnetically trapped protons from the inner radiation belt (SAA). The fluxes as a function of equatorial pitch angle and McIlwain L-shell are reported.
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20.
  • Galper, A. M., et al. (författare)
  • International Russian-Italian mission "Rim-Pamela
  • 2009
  • Ingår i: Proceedings of the 13th Lomonosov Conference on Elementary Particle Physics. - : WORLD SCIENTIFIC. - 9812837582 - 9789812837585 ; , s. 199-206
  • Konferensbidrag (refereegranskat)abstract
    • The successful launch of spacecraft "RESURS DK" 1 with precision magnetic spectrometer "PAMELA" onboard was executed at Baikonur cosmodrome 15 June 2006. The primary phase of realization of International Russian-Italian Project "RIM-PAMELA" with German and Swedish scientists' participation has begun since the launch of instrument "PAMELA" that has mainly been directed to investigate the fluxes of galactic cosmic rays. This report contains the main scientific Project's tasks and the conditions of science program's implementation after one year since exploration has commenced.
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21.
  • Picozza, P., et al. (författare)
  • Cosmic ray studies with PAMELA experiment
  • 2011
  • Ingår i: Proceedings of the 14th Lomonosov Conference on Elementary Particle Physics: Particle Physics at the Year of Astronomy. - 9814329673 - 9789814329675 ; , s. 200-206
  • Konferensbidrag (refereegranskat)abstract
    • The instrument PAMELA, in orbit since June 15th, 2006 on board of the Russian satellite Resurs DK1, is daily delivering to ground 16 Gigabytes of data. The apparatus is designed to study charged particles in the cosmic radiation, with a particular focus on antiparticles for searching antimatter and signals of dark matter annihilation. A combination of a magnetic spectrometer and different detectors allows antiparticles to be reliably identified from a large background of other charged particles. New results on the antiproton-to-proton and positron-toall electron ratios over a wideenergy range (1-100 GeV) have been obtained from the PAMELA mission. These data are mainly interpreted in terms of dark matter annihilation or pulsar contribution.
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22.
  • Adriani, O., et al. (författare)
  • Positrons and electrons in primary cosmic rays as measured in the PAMELA experiment
  • 2009
  • Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 73:5, s. 568-570
  • Tidskriftsartikel (refereegranskat)abstract
    • The PAMELA experiment is being carried out on board the Russian satellite Resurs DK1 placed in the near-earth near-polar orbit on June 15, 2006. The apparatus comprising a silicon-strip magnetic spectrometer and an electromagnetic calorimeter allows measurement of electron and positron fluxes in cosmic rays in a wide energy interval from ∼100 MeV to hundreds of GeV. The high-energy electron and positron separation technique is discussed and the data on positron-to-electron ratio in primary cosmic rays up to E ≃ 10 GeV from the 2006 - 2007 measurements are reported in this work.
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23.
  • Adriani, O., et al. (författare)
  • Time Dependence Of The Proton Flux Measured By Pamela During The 2006 July-2009 December Solar Minimum
  • 2013
  • Ingår i: Astrophysical Journal. - : IOP Publishing. - 0004-637X .- 1538-4357. ; 765:2, s. 91-
  • Tidskriftsartikel (refereegranskat)abstract
    • The energy spectra of galactic cosmic rays carry fundamental information regarding their origin and propagation. These spectra, when measured near Earth, are significantly affected by the solar magnetic field. A comprehensive description of the cosmic radiation must therefore include the transport and modulation of cosmic rays inside the heliosphere. During the end of the last decade, the Sun underwent a peculiarly long quiet phase well suited to study modulation processes. In this paper we present proton spectra measured from 2006 July to 2009 December by PAMELA. The large collected statistics of protons allowed the time variation to be followed on a nearly monthly basis down to 400 MV. Data are compared with a state-of-the-art three-dimensional model of solar modulation.
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24.
  • Grishantseva, L. A., et al. (författare)
  • Sub-cutoff electrons and positrons in the near Earth space
  • 2009
  • Ingår i: 31st International Cosmic Ray Conference, ICRC 2009. - : University of Lodz.
  • Konferensbidrag (refereegranskat)abstract
    • Precise spectra of electron and positron fluxes in energy range from 80 MeV to several GeV below the geomagnetic cutoff rigidity were obtained using data of the PAMELA spectrometer. It was launched on June 15th 2006 onboard the Resurs-DK satellite on an elliptical orbit (the inclination is 70°, the altitude is 350-610 km). The work presents measurements of secondary lepton fluxes produced in interactions of cosmic ray protons with the atmosphere in the near Earth space (out of the South Atlantic Anomaly). Latitudinal dependences are discussed. These results are particularly interesting for more accurate definition of electron/positron flux model in the Earth magnetosphere.
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25.
  • Adriani, O., et al. (författare)
  • Latest results from the Pamela experiment
  • 2009
  • Ingår i: Proceedings of Science. ; , s. 1-6
  • Konferensbidrag (refereegranskat)abstract
    • In this paper we present the latest results of the Pamela satellite experiment, focusing in particular on the p̄/p and the e +/(e+ +e-) ratios.
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26.
  • Boezio, M., et al. (författare)
  • PAMELA and indirect dark matter searches
  • 2009
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 11, s. 105023-
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a review of the experimental results obtained by PAMELA in measuring the (p, (p) over bar ) and e(+/-) abundance in cosmic rays. In this context, we discuss the interpretation of the observed anomalous positron excess in terms of the annihilation of dark matter particles as well as in terms of standard astrophysical sources. Moreover we show the constraints on dark matter models from (p) over bar data.
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27.
  • Mocchiutti, E., et al. (författare)
  • PAMELA and electrons
  • 2011
  • Konferensbidrag (refereegranskat)abstract
    • The 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail counter scintillator and a neutron detector. The combination of these devices allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV-100's GeV) with high statistics. The measurement of the positron to electron fraction and of the electron energy spectrum in order to search for exotic sources, such as dark matter particle annihilations, are within the PAMELA primary scientific goal.
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28.
  • Mocchiutti, E., et al. (författare)
  • Precision studies of cosmic rays with the PAMELA satellite experiment
  • 2009
  • Ingår i: 2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5. - : IEEE. - 9781424439621 ; , s. 2125-2130
  • Konferensbidrag (refereegranskat)abstract
    • The PAMELA satellite experiment was launched into low earth orbit on June 15th 2006. The combination of a permanent magnet silicon strip spectrometer, and a silicon-tungsten imaging calorimeter allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV - 200 GeV). A primary scientific goal is to search for dark matter particle annihilations by measuring the energy spectra of cosmic ray antiparticles. Latest results from the PAMELA experiment will be reviewed with a particular focus on cosmic ray antiprotons and positrons. The status of PAMELA measurements for other cosmic ray species will also be reviewed.
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29.
  • Adriani, O., et al. (författare)
  • An anomalous positron abundance in cosmic rays with energies 1.5-100 GeV
  • 2009
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 458:7238, s. 607-609
  • Tidskriftsartikel (refereegranskat)abstract
    • Antiparticles account for a small fraction of cosmic rays and are known to be produced in interactions between cosmic-ray nuclei and atoms in the interstellar medium(1), which is referred to as a 'secondary source'. Positrons might also originate in objects such as pulsars(2) and microquasars(3) or through dark matter annihilation(4), which would be 'primary sources'. Previous statistically limited measurements(5-7) of the ratio of positron and electron fluxes have been interpreted as evidence for a primary source for the positrons, as has an increase in the total electron+positron flux at energies between 300 and 600 GeV (ref. 8). Here we report a measurement of the positron fraction in the energy range 1.5-100 GeV. We find that the positron fraction increases sharply overmuch of that range, in a way that appears to be completely inconsistent with secondary sources. We therefore conclude that a primary source, be it an astrophysical object or dark matter annihilation, is necessary.
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30.
  • Boezio, M., et al. (författare)
  • The PAMELA space mission for antimatter and dark matter searches in space
  • 2012
  • Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 213:1-3, s. 147-158
  • Tidskriftsartikel (refereegranskat)abstract
    • The PAMELA satellite-borne experiment has presented new results on cosmic-ray antiparticles that can be interpreted in terms of DM annihilation or pulsar contribution. The instrument was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The combination of a permanent magnet silicon strip spectrometer and a silicon-tungsten imaging calorimeter allows precision studies of the charged cosmic radiation to be conducted over a wide energy range with high statistics. The primary scientific goal is the measurement of the antiproton and positron energy spectrum in order to search for exotic sources. PAMELA is also searching for primordial antinuclei (anti-helium), and testing cosmic-ray propagation models through precise measurements of the antiparticle energy spectrum and precision studies of light nuclei and their isotopes. This talk illustrates the most recent scientific results obtained by the PAMELA experiment.
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31.
  • De Simone, N., et al. (författare)
  • Comparison of models and measurements of protons of trapped and secondary origin with PAMELA experiment
  • 2009
  • Ingår i: 31st International Cosmic Ray Conference, ICRC 2009. - : University of Lodz.
  • Konferensbidrag (refereegranskat)abstract
    • PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: Antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antinuclei with a precision of the order of 10-8). The experiment, housed on board the Russian Resurs- DK1 satellite, was launched on June, 15th 2006 in a 350x600 km orbit with an inclination of 70 degrees. In this work we present the measurement of galactic and reentrant albedo proton spectra in the energy range between 100 MeV and 300 GeV. The galactic protons refer to the period 2006-2008, showing evidence of Solar modulation effects even during the solar minimum.
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32.
  • Mocchiutti, E., et al. (författare)
  • The PAMELA space experiment
  • 2009
  • Ingår i: Proceedings of the 44th Rencontres de Moriond - 2009 Electroweak Interactions and Unified Theories, EW 2009. - : Gioi Publishers. ; , s. 317-324
  • Konferensbidrag (refereegranskat)abstract
    • The 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail counter scintillator and a neutron detector. The combination of these devices allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV - 100's GeV) with high statistics. The primary scientific goal is the measurement of the antiproton and positron energy spectrum in order to search for exotic sources, such as dark matter particle annihilations. PAMELA is also searching for primordial antinuclei (anti-helium) and testing cosmic-ray propagation models through precise measurements of the anti-particle energy spectrum and precision studies of light nuclei and their isotopes. Moreover, PAMELA is investigating phenomena connected with solar and earth physics.
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33.
  • Mori, N., et al. (författare)
  • Measurement of the He nuclei flux at high energies with the PAMELA experiment
  • 2009
  • Ingår i: 31st International Cosmic Ray Conference, ICRC 2009. - : University of Lodz.
  • Konferensbidrag (refereegranskat)abstract
    • The PAMELA experiment is a satellitebased apparatus launched in June 2006. Its core instrument is a magnetic spectrometer, whose high spatial resolution (∼ 3 micron) provides the discriminative power to separate particles and antiparticles. It can measure the momentum and the energy-loss rate of an incident particles, thus allowing to identify higher charges (up to Z ≃ 5). The main goal for PAMELA is a precise measurement of the light antimatter component in cosmic rays (antiprotons, positrons), with unprecedented statistics and over a largely unexplored energy range. The instrument characteristics and the large statistics allow to precisely measure absolute fluxes for various cosmic-ray species up to high energy. Here the He flux analysis above some GeV is presented.
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34.
  • Papini, P., et al. (författare)
  • Latest results from PAMELA
  • 2009
  • Konferensbidrag (refereegranskat)abstract
    • The PAMELA experiment is a satellite-borne apparatus designed to study charged particles in the cosmic radiation, with a particular focus on antiparticles. The detector is housed on the Resurs-DK1 satellite and it is taking data since June 2006. The main parts of the apparatus are a magnetic spectrometer, which is equipped with a silicon-microstrip tracking system and which is used to measure the rigidity and the charge of particles, and a silicon/tungsten electromagnetic calorimeter which provides particle identification. The main results about the antiparticles component of cosmic rays obtained during the first 500 days of data taking are summarized here.
  •  
35.
  • Picozza, P., et al. (författare)
  • Dark Matter Research and the PAMELA Space Mission
  • 2009
  • Ingår i: SOURCES AND DETECTION OF DARK MATTER AND DARK ENERGY IN THE UNIVERSE. - : AIP. ; , s. 141-150
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • On the 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Bajkonur cosmodrome and since July 2006 it has been collected data. The core of the apparatus is a silicon-microstrip magnetic spectrometer combined with a time-of-flight system, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail counter scintillator and a neutron detector. The overall devices allow precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV - 100's GeV) with high statistics. The primary scientific goal is the measurement of the antiproton and positron energy spectra in order to search for exotic sources, such as dark matter particle annihilation. PAMELA is also searching for primordial antinuclei ((He) over bar). Concomitant, but not secondary, goals are the measurements of light nuclei and their isotopes for studying the energy dependence of cosmic ray lifetimes in the Galaxy, the monitoring of the solar activity and the study of the radiation belts.
  •  
36.
  • Sparvoli, R., et al. (författare)
  • Cosmic rays studies with the PAMELA space experiment
  • 2009
  • Ingår i: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics. - 1124-1896 .- 1826-9885. ; 32:5-6, s. 1-10
  • Tidskriftsartikel (refereegranskat)abstract
    • The instrument PAMELA, in orbit since June 15th, 2006 on board the Russian satellite Resurs DK1, is delivering to ground 16 Gigabytes of data per day. The apparatus is designed to study charged particles in the cosmic radiation, with a particular focus on antiparticles as a possible signature of dark matter annihilation in the galactic halo; the combination of a magnetic spectrometer and different detectors-indeed- allows antiparticles to be reliably identified from a large background of other charged particles. New results on the antiproton-to-proton and positron-to-all-electron ratios over a wide energy range (1-100GeV) have been recently released by the PAMELA Collaboration, and will be summarized in this paper. While the antiproton-to-proton ratio does not show particular differences from an antiparticle standard secondary production, in the positron-to-all-electron ratio an enhancement is clearly seen at energies above 10 GeV. Possible interpretations of this effect will be briefly discussed.
  •  
37.
  • Sparvoli, R., et al. (författare)
  • Cosmic rays studies with the PAMELA space experiment
  • 2010
  • Ingår i: Frascati Physics Series. - 9788874380534 ; , s. 1-10
  • Konferensbidrag (refereegranskat)abstract
    • The instrument PAMELA, in orbit since June 15th, 2006 on board the Russian satellite Resurs DK1, is delivering to ground 16 Gigabytes of data per day. The apparatus is designed to study charged particles in the cosmic radiation, with a particular focus on antiparticles as a possible signature of dark matter annihilation in the galactic halo; the combination of a magnetic spectrometer and different detectors-indeed-allows antiparticles to be reliably identified from a large background of other charged particles. New results on the antiproton-to-proton and positron-to-all-electron ratios over a wide energy range (1-100GeV) have been recently released by the PAMELA Collaboration, and will be summarized in this paper. While the antiproton-to-proton ratio does not show particular differences from an antiparticle standard secondary production, in the positron-to-all-electron ratio an enhancement is clearly seen at energies above 10GeV. Possible interpretations of this effect will be briefly discussed.
  •  
38.
  • Casolino, M., et al. (författare)
  • Two years of flight of the Pamela experiment : Results and perspectives
  • 2009
  • Ingår i: Journal of the Physical Society of Japan. - 0031-9015 .- 1347-4073. ; 78:Suppl. A, s. 35-40
  • Tidskriftsartikel (refereegranskat)abstract
    • PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antinuclei with a precision of the order of 10~8). The experiment, housed on board the Russian Resurs-DKl satellite, was launched on June, 15th 2006 in a 350 x 600 km orbit with an inclination of 70 degrees. In this work we describe the scientific objectives and the performance of PAMELA in its first two years of operation. Data on protons of trapped, secondary and galactic nature - as well as measurements of the December 13th 2006 Solar Particle Event - are also provided.
  •  
39.
  • Bonvicini, V., et al. (författare)
  • Performance of the PAMELA Si-W imaging calorimeter in space
  • 2009
  • Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 160, s. 012039-
  • Tidskriftsartikel (refereegranskat)abstract
    • The Payload for Antimatter-Matter Exploration and Light Nuclei Astrophysics (PAMELA), primarily designed to directly measure antiparticles (antiprotons and positrons) in the cosmic radiation, was launched successfully on June 15th, 2006, and, since then, it is in continuous data taking. The calorimeter of the PAMELA apparatus has been designed to identify antiprotons from an electron background and positrons from a background of protons with high efficiency and rejection power. It is a sampling silicon-tungsten imaging calorimeter, which comprises 44 single-sided silicon sensor planes (380 μm thick) interleaved with 22 plates of tungsten absorber (0.74 X0 each). It is the first silicon-tungsten calorimeter to be launched in space. In this work we present the in-orbit performance of the calorimeter, including the measured identification capabilities. The calorimeter provides a proton rejection factor of ∼105 while keeping a high efficiency in selecting electrons and positrons, thus fulfilling the identification power needed to reach the primary scientific objectives of PAMELA. We show also that, after almost two years of operation in space, the calorimeter is still performing nominally.
  •  
40.
  • Casolino, M., et al. (författare)
  • Cosmic ray measurements with Pamela experiment
  • 2009
  • Konferensbidrag (refereegranskat)abstract
    • PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature hi a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antinuclei with a precision of the order of 10(-8)). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15(th) 2006 in a 350 X 600 km orbit with an inclination of 70 degrees. In this work we describe the scientific objectives awl the performance of PAMELA in its first two years of operation. Data oil protons of trapped, secondary and galactic nature - as well as measurements of the December 13(th) 2006 Solar Particle Event - are also provided.
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