| 51. |
- Menn, W., et al.
(författare)
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Lithium and Beryllium Isotopes with the PAMELA Experiment
- 2018
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Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 862:2
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Tidskriftsartikel (refereegranskat)abstract
- The cosmic ray (CR) lithium and beryllium (Li-6, Li-7, Be-7, Be-9, Be-10) isotopic composition has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on board the Resurs-DKJ satellite on 2006 June 15. The rare lithium and beryllium isotopes in CRs are believed to originate mainly from the interaction of high-energy carbon, nitrogen, and oxygen nuclei with the interstellar medium (ISM), but also on "tertiary" interactions in the ISM (i.e., produced by further fragmentation of secondary beryllium and boron). In this paper, the isotopic ratios Li-7/Li-6 and Be-7/(Be-9 + Be-10), measured between 150 and 1100 MeV n(-1) using two different detector systems from 2006 July to 2014 September, will be presented.
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| 52. |
- Mergè, M., et al.
(författare)
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PAMELA measurements of solar energetic particle spectra
- 2017
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- The charged particle acceleration and transport during solar events have been widely studied in the past decades. The satellite-borne PAMELA experiment has been continuously collecting data since 2006. The apparatus is designed to study charged particles in the cosmic radiation. The combination of permanent magnet, silicon micro-strip spectrometer and silicon-tungsten imaging calorimeter, with the redundancy of instrumentation allows very precise studies on the physics of cosmic rays in a wide energy range and with high statistics. This makes PAMELA a well suited instrument for Solar Energetic Particles (SEP) observations. Not only it spans the energy range between the ground-based neutron monitor data and the observations of SEPs from space, but also PAMELA carries out the first direct measurements of SEP energy spectra, composition and angular distribution. PAMELA has observed many SEP events in solar cycle 24, offering unique opportunity to address several questions on high-energy SEP origin. A preliminary analysis on proton spectra during several events of the 24th solar cycle is presented.
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| 53. |
- Mikhailov, V., et al.
(författare)
-
Measurements of electron and positron fluxes below the geomagnetic cutoff by the PAMELA magnetic spectrometer
- 2017
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- We present a measurements of electron and positron fluxes below the geomagnetic cutoff rigidity in wide energy range from 50 MeV to several GeVs by the PAMELA magnetic spectrometer. The instrument was launched on June 15th 2006 on-board the Resurs-DK satellite on low orbit with 70 degrees inclination and altitude between 350 and 600 km. Features of spatial distributions of secondary electrons and positrons in the near Earth space, including the South Atlantic Anomaly, were investigated in terms of lifetime and geographical origin. The separation in stably trapped, long lifetime quasi-trapped, and short lifetime albedo components was performed on base of back tracing procedure in geomagnetic field. A significant difference in relative abundance of positrons with respect to electrons is seen for the stable trapped and the quasi-trapped populations what pointing out on differences in trapping mechanism of those populations.
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| 54. |
- Mikhailov, V. V., et al.
(författare)
-
Modulation of electrons and positrons in 2006–2015 in the PAMELA experiment
- 2017
-
Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - : Allerton Press Incorporation. - 1062-8738. ; 81:2, s. 154-156
-
Tidskriftsartikel (refereegranskat)abstract
- The PAMELA magnetic spectrometer was launched aboard the Resurs DK-1 satellite into a nearpolar circumterrestrial orbit with an altitude of 350–600 km to study fluxes of the particles and antiparticles of cosmic rays in the wide energy range of ~80 MeV to several hundred gigaelectronvolts. The results from observations of temporal variations in electron and positron fluxes in 2006–2015 are presented. The ratio of electron and positron fluxes measured in this time interval reveals a dependence on the rigidity of particles, the solar activity, and the polarity of the solar magnetic field.
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| 55. |
- Mikhailov, V. V., et al.
(författare)
-
Searching for anisotropy of positrons and electrons in the PAMELA experiment
- 2015
-
Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 79:3, s. 298-301
-
Tidskriftsartikel (refereegranskat)abstract
- The PAMELA experiment has been under way aboard the Resurs DK-1 satellite since June 2006. The results have revealed an increase in the ratio of the positron intensity to the total electron and positron intensity at energies in excess of 10 GeV. This increase suggests an additional source of cosmic rays that is associated with either some astrophysical objects (e.g., pulsars) or the probable annihilation of particles of dark matter. Local positron sources can produce notable anisotropy in their flux. The results from the search for anisotropy of positrons and electrons in the events detected by the PAMELA experiment in the 2006–2013 timeframe are described in detail in this work.
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| 56. |
- Mikhailov, V. V., et al.
(författare)
-
Secondary positrons and electrons in near-Earth space in the PAMELA experiment
- 2017
-
Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - : Allerton Press Incorporation. - 1062-8738. ; 81:2, s. 203-205
-
Tidskriftsartikel (refereegranskat)abstract
- Fluxes of electrons and positrons with energies above ~100 MeV in the near-Earth space are measured with the PAMELA magnetic spectrometer aboard the Resurs DK-1 satellite launched on June 15, 2006, into a quasipolar orbit with an altitude of 350–600 km and an inclination of 70°. Calculating the trajectories of detected electrons and positrons in the magnetosphere of the Earth allows us to determine their origin and isolate particles produced during interaction between cosmic rays and the residual atmosphere. Spatial distributions of albedo, quasitrapped, and trapped (in the radiation belt) positrons and electrons are presented. The ratio of positron and electron fluxes suggests that the fluxes of trapped particles of the radiation belt and quasitrapped secondary particles have different mechanisms of formation.
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| 57. |
- Mikhailov, V. V., et al.
(författare)
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Trapped Positrons and Electrons in the Inner Radiation Belt According to Data of the PAMELA Experiment
- 2018
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Ingår i: Physics of Atomic Nuclei. - : PLEIADES PUBLISHING INC. - 1063-7788 .- 1562-692X. ; 81:4, s. 515-519
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of secondary-electron and secondary-positron fluxes below the geomagnetic cutoff in near-Earth space were performed by means of the PAMELA magnetic spectrometer installed on board the Resurs-DK1 satellite launched on June 15, 2006, in an elliptical orbit of inclination 70A degrees and altitude 350 to 600 km. This spectrometer permits measuring the fluxes of electrons and positrons over a wide energy range, as well as determining their spatial distributions to a precision of about 2A degrees. A calculation of particle trajectories in the geomagnetic field makes it possible to separate electrons and positrons originating from cosmic-ray interactions in the Earth's magnetosphere. The spatial distributions of quasitrapped, trapped, and short-lived albedo positrons and electrons of energy above 70 MeV in the radiation belt were analyzed. The ratio of the electron-to-positron fluxes and the energy spectra of the electrons and positrons in question are indicative of different productionmechanisms for stably trapped and quasitrapped secondary particles.
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| 58. |
- Mori, N., et al.
(författare)
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PAMELA measurements of the boron and carbon spectra
- 2015
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Ingår i: 24TH EUROPEAN COSMIC RAY SYMPOSIUM (ECRS). - : IOP Publishing.
-
Konferensbidrag (refereegranskat)abstract
- The satellite-borne PAMELA experiment is aimed at precision measurements of the charged light component of the cosmic-ray spectrum, with a particular focus on antimatter. It consists of a magnetic spectrometer, a time-of-flight system, an electromagnetic calorimeter with a tail catcher scintillating layer, an anticoincidence system and a neutron detector. PAMELA has measured the absolute fluxes of boron and carbon and the B/C ratio, which plays a central role in galactic propagation studies in order to derive the injection spectra at sources from measurements at Earth. In this paper, the data analysis techniques and the final results are presented.
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| 59. |
- Mori, N., et al.
(författare)
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The PAMELA experiment and cosmic ray observations
- 2015
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Ingår i: NUCLEAR AND PARTICLE PHYSICS PROCEEDINGS. - : Elsevier. - 2405-6014. ; , s. 242-244
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Konferensbidrag (refereegranskat)abstract
- The PAMELA space experiment is aimed at precise measurements of the charged light component of the cosmic ray spectrum in the energy range spanning from the sub-GeV region to the TeV region, with a particular focus on antimatter. The instrument consists of a magnetic spectrometer, an electromagnetic sampling calorimeter,a time-off-light system, an anticoincidence shield, a tail-catcher scintillator and a neutron detector. Launched in June 2006 and hosted on the Resurs-DK1 satellite, PAMELA has been taking data for more than eight years, providing scientific results with unprecedented statistics and a continuous monitoring of the sun activity and the heliosphere.
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| 60. |
- Panico, B., et al.
(författare)
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Study on CRE arrival distributions with PAMELA experiment
- 2015
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Ingår i: Proceedings of Science. - : Proceedings of Science (PoS).
-
Konferensbidrag (refereegranskat)abstract
- From 2009, several experiments, like PAMELA, FERMI and AMS, have shown a rise in the fraction of positrons versus electrons+positrons. One of the most probable explanation is due to the presence of nearby sources, like SNRs or pulsars. PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) is a ballooon-borne experiment and is collecting data since 15 June 2006. Its quasi-polar orbit permits to perform a survey in each direction of the sky. The study of the arrival distribution of cosmic ray electrons and positrons from different regions allows the exploration of different origins for the excess.
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