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KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Measurements of quasi-trapped electron and positron fluxes with PAMELA2009In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 114, p. A12218-Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
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 DETECTOR2011In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 742, no 2, p. 102-Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
A statistical procedure for the identification of positrons in the PAMELA experiment2010In: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 34, no 1, p. 1-11Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
PAMELA Results on the Cosmic-Ray Antiproton Flux from 60 MeV to 180 GeV in Kinetic Energy2010In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 105, no 12, p. 121101-Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
PAMELA Measurements of Cosmic-Ray Proton and Helium Spectra2011In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 332, no 6025, p. 69-72Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Measurement of the isotopic composition of hydrogen and helium nuclei in cosmic rays with the PAMELA experiment2013In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 770, no 1, p. 2-Article in journal (Refereed)

The satellite-borne experiment PAMELA has been used to make new measurements of cosmic ray H and He isotopes. The isotopic composition was measured between 100 and 600 MeV /n for hydrogen and between 100 and 900 MeV /n for helium isotopes over the 23rd solar minimum from 2006 July to 2007 December. The energy spectrum of these components carries fundamental information regarding the propagation of cosmic rays in the galaxy which are competitive with those obtained from other secondary to primary measurements such as B/C.

KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics.
Time Dependence Of The Proton Flux Measured By Pamela During The 2006 July-2009 December Solar Minimum2013In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 765, no 2, p. 91-Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics.
Measurements of cosmic-ray proton and helium spectra with the PAMELA calorimeter2013In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 51, no 2, p. 219-226Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics.
Cosmic-Ray Electron Flux Measured by the PAMELA Experiment between 1 and 625 GeV2011In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 106, no 20, p. 201101-Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Measurement of the flux of primary cosmic ray antiprotons with energies of 60 MeV to 350 GeV in the PAMELA experiment2013In: JETP Letters: Journal of Experimental And Theoretical Physics Letters, ISSN 0021-3640, E-ISSN 1090-6487, Vol. 96, no 10, p. 621-627Article in journal (Refereed)

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.

KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
The discovery of geomagnetically trapped cosmic-ray antiprotons2011In: Astrophysical Journal Letters, ISSN 2041-8205, Vol. 737, no 2, p. L29-Article in journal (Refereed)

The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60-750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three orders of magnitude at the present solar minimum, and exceeds the sub-cutoff antiproton flux outside radiation belts by four orders of magnitude, constituting the most abundant source of antiprotons near the Earth.

• 12. Bazilevskaya, G. A.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Solar proton events at the end of the 23rd and start of the 24th solar cycle recorded in the PAMELA experiment2013In: Bulletin of the Russian Academy of Sciences: Physics, ISSN 1062-8738, Vol. 77, no 5, p. 493-496Article in journal (Refereed)

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.

• 13. Boezio, M.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
The PAMELA space mission for antimatter and dark matter searches in space2012In: Hyperfine Interactions, ISSN 0304-3843, E-ISSN 1572-9540, Vol. 213, no 1-3, p. 147-158Article in journal (Refereed)

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.

• 14.
Ist Nazl Fis Nucl, Sez Naples, I-80126 Naples, Italy..
KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics. Moscow Engn Phys Inst, Moscow RU-11540, Russia..
Search for cosmic ray electron-positron anisotropies with the Pamela data2013In: 23RD EUROPEAN COSMIC RAY SYMPOSIUM (AND 32ND RUSSIAN COSMIC RAY CONFERENCE), IOP PUBLISHING LTD , 2013, article id 012055Conference paper (Refereed)

Using data taken by the Pamela experiment during 5 years of operation we studied the anisotropy in the arrival direction of cosmic ray electrons and positrons with energy above 40 GeV. We report on a study of anisotropy in the e(+/-) flux at different angular scales extending from 30 degrees up to 90 degrees, further more a directional analysis has been performed around the Sun direction. The observed distribution of arrival directions is consistent with the isotropic expectation at any angular scale used in this study and no significant evidence of strong anisotropies has been observed, also the analysis around the Sun direction did not show any significant excess.

• 15. De Simone, N.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
PAMELA: Measurements of matter and antimatter in space2011In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 34, no 3, p. 79-87Article in journal (Refereed)

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.

• 16. Giaccari, U.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Anisotropy studies in the cosmic ray proton flux with the PAMELA experiment2013In: 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, 2013, p. 123-128Conference paper (Refereed)

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.

• 17. Mayorov, A. G.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Antiprotons of galactic cosmic radiation in the PAMELA experiment2013In: Bulletin of the Russian Academy of Sciences: Physics, ISSN 1062-8738, Vol. 77, no 5, p. 602-605Article in journal (Refereed)

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.

• 18. Mayorov, A. G.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Upper limit on the antihelium flux in primary cosmic rays2011In: JETP Letters: Journal of Experimental And Theoretical Physics Letters, ISSN 0021-3640, E-ISSN 1090-6487, Vol. 93, no 11, p. 628-631Article in journal (Refereed)

The explanation of the observed baryon asymmetry, i.e., the almost complete absence of antimatter in the visible part of the universe, is one of the most important problems in cosmology. The real asymmetry value can be determined by direct measurements of the fluxes of antinuclei with charges |Z| a (c) 3/4 2 in primary cosmic rays near the Earth. The results of the search for antihelium using data from the PAMELA experiment obtained from June 2006 to December 2009 are presented. No events with a charge of -2 have been detected in the rigidity range of 0.6-600 GV. An upper limit on the antihelium/helium flux ratio has been presented as a function of the energy. An integral upper level of 4.7 x 10(-7) is the lowest limit at rigidities above 14 GV.

• 19. Menn, W.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics.
The PAMELA space experiment2013In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 51, no 2, p. 209-218Article in journal (Refereed)

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.

• 20. Mikhailov, V.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Cosmic ray electron and positron spectra measured with PAMELA2013In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 409, no 1, p. 012035-Article in journal (Refereed)

The PAMELA experiment is carried out on board of the satellite Resurs DK1 launched on June 15th 2006 on polar orbit (the inclination is 70, the altitude is 350-600 km). The instrument which consists of magnetic spectrometer, silicon-tungsten imaging electromagnetic calorimeter gives a possibility to measure electron and positron fluxes over wide energy range from hundreds MeVs to hundreds GeVs. Measurements made in June 2006- January 2010 are presented and compared with other results and models. Positron spectrum appears to be harder than standard diffusive propagation models predict.

• 21. Mocchiutti, E.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Precision studies of cosmic rays with the PAMELA satellite experiment2009In: 2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5 / [ed] Yu, B, IEEE , 2009, p. 2125-2130Conference paper (Refereed)

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.

• 22. Mocchiutti, E.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Results from PAMELA2011In: NUCL PHYS B-PROC SUP, 2011, Vol. 217, p. 243-248Conference paper (Refereed)

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.

• 23. Mocchiutti, E.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
PAMELA and electrons2011Conference paper (Refereed)

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.

• 24. Papini, P.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Latest results from PAMELA2009Conference paper (Refereed)

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.

• 25.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Measurements of Cosmic Ray Antiprotons with PAMELA2010Licentiate thesis, monograph (Other academic)
• 26.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Measurements of cosmic ray antiprotons with PAMELA and studies of propagation models2012Doctoral thesis, monograph (Other academic)

Studying the acceleration and propagation mechanisms of Galactic cosmic rays can provide information regarding astrophysical sources, the properties of our Galaxy, and possible exotic sources such as dark matter. To understand cosmic ray acceleration and propagation mechanisms, accurate measurements of different cosmic ray elements over a wide energy range are needed. The PAMELA experiment is a satellite-borne apparatus which allows different cosmic ray species to be identified over background.

Measurements of the cosmic ray antiproton flux and the antiproton-to-proton flux ratio from 1.5 GeV to 180 GeV are presented in this thesis, employing the data collected between June 2006 and December 2008. Compared to previous experiments, PAMELA extends the energy range of antiproton measurements and provides significantly higher statistics. During about 800 days of data collection, PAMELA identified approximately 1300 antiprotons including 61 above 31.7 GeV. A dramatic improvement of statistics is evident since only 2 events above 30 GeV are reported by previous experiments. The derived antiproton flux and antiproton-to-proton flux ratio are consistent with previous measurements and generally considered to be produced as secondary products when cosmic ray protons and helium nuclei interact with the interstellar medium.

To constrain cosmic ray acceleration and propagation models, the antiproton data measured by PAMELA were further used together with the proton spectrum reported by PAMELA, as well as the B/C data provided by other experiments. Statistical tools were interfaced with the cosmic ray propagation package GALPROP to perform the constraining analyses.

Different diffusion models were studied. It was shown in this work that only current PAMELA data, i.e. the antiproton-to-proton ratio and the proton flux, are not able to place strong constraints on propagation parameters. Diffusion models with a linear diffusion coefficient and modified diffusion models with a low energy dependence of the diffusion coefficient were studied in the $\chi^{2}$ study. Uncertainties on the parameters and the goodness of fit of each model were given. Some models are further studied using the Bayesian inference. Posterior means and errors of the parameters base on our prior knowledge on them were obtained in the Bayesian framework. This method also allowed us to understand the correlation between parameters and compare models.

Since the B/C ratio used in this analysis is from experiments other than PAMELA, future PAMELA secondary-to-primary ratios (B/C, $^{2}$H/$^{4}$He and $^{3}$He/$^{4}$He) can be used to avoid the data sets inconsistencies between different experiments and to minimize uncertainties on the solar modulation parameters. More robust and tighter constraints are expected. The statistical techniques have been demonstrated useful to constrain models and can be extended to other observations, e.g. electrons, positrons, gamma rays etc. Using these channels, exotic contributions from, for example, dark matter will be further investigated in future.

• 27.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
Measurements of cosmic-ray antiprotons with PAMELA2011In: Astrophysics and Space Sciences Transactions (ASTRA), ISSN 1810-6528, E-ISSN 1810-6536, Vol. 7, no 2, p. 225-228Article in journal (Refereed)

The PAMELA experiment is a satellite-borne apparatus designed to study charged particles, and especially antiparticles, in the cosmic radiation. The apparatus is mounted on the Resurs DK1 satellite which was launched on 15 June 2006. PAMELA has been traveling around the earth along an elliptical and semi-polar orbit for almost five years. It mainly consists of a permanent magnetic spectrometer, a time of flight system and an electromagnetic imaging calorimeter, which allows antiprotons to be identified from a dominating cosmic-ray background. New measurements of the cosmic-ray antiproton flux and the antiproton-to-proton flux ratio between 60 MeV and 180 GeV are presented, employing data collected between June 2006 and December 2008. Compared to previous experiments, PAMELA extends the energy range of antiproton measurements and provides significantly higher statistics. The derived antiproton flux and antiproton-to-proton flux ratio indicates that the main source of cosmic-ray antiprotons is considered to be secondary production and no primary contribution has to be invoked.

• 28.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. Oskar Klein Centre for Cosmoparticle Physics, Sweden .
LPSC, UJF Grenoble 1, CNRS/IN2P3, INP de Grenoble, France. Department of Physics, Stockholm University. Oskar Klein Centre for Cosmoparticle Physics, Sweden.
Constraints on cosmic-ray propagation and acceleration models from recent data2011In: Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011, Institute of High Energy Physics , 2011, Vol. 6, p. 228-231Conference paper (Refereed)

We are studying the constraints obtained on transport and acceleration mechanisms of galactic cosmic rays by using statistical tools in combination with the propagation package GALPROP and recent PAMELA data. Using only PAMELA data allows us to avoid inconsistencies between data sets from different experiments, minimise uncertainties on solar modulation parameters, and have a complementary and precise data set on (anti-)matter as well as primary and secondary nuclei over 3 orders of magnitude in energy. This allows us to simultaneously place strong constraints on cosmic-ray propagation and acceleration models. We describe our methodology and present some preliminary results in this paper.

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