ABSTRACT The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) detector was launched on board the Russian Resurs-DK1 satellite on 2006 June 15. The data collected ...during the first four years have been used to search for large-scale anisotropies in the arrival directions of cosmic ray positrons. The PAMELA experiment allows for a full sky investigation, with sensitivity to global anisotropies in any angular window of the celestial sphere. Data samples of positrons in the rigidity range of 10 GV R 200 GV were analyzed. This article discusses the method and the results of the search for possible local sources through the analysis of anisotropy in positron data compared to the proton background. The resulting distributions of arrival directions are found to be isotropic. Starting from the angular power spectrum, a dipole anisotropy upper limit of δ = 0.076 at the 95% confidence level is determined. An additional search is carried out around the Sun. No evidence of an excess correlated with that direction was found.
The PAMELA satellite experiment is providing comprehensive observations of the interplanetary and magnetospheric radiation in the near-Earth environment. Thanks to its identification capabilities and ...the semi-polar orbit, PAMELA is able to precisely measure the energetic spectra and the angular distributions of the different cosmic-ray populations over a wide latitude region, including geomagnetically trapped and albedo particles. Its observations comprise the solar energetic particle events between solar cycles 23 and 24, and the geomagnetic cutoff variations during magnetospheric storms. PAMELA’s measurements are supported by an accurate analysis of particle trajectories in the Earth’s magnetosphere based on a realistic geomagnetic field modeling, which allows the classification of particle populations of different origin and the investigation of the asymptotic directions of arrival.
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 10TeV, thus extending the PAMELA observational range based on the magnetic spectrometer measurement.
The main goal of the FAMU experiment is the measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen ΔEhfs (μ-p)1S. The physical process behind this experiment is the ...following: μp are formed in a mixture of hydrogen and a higher-Z gas. When absorbing a photon at resonance-energy ΔEhfs ≈ 0.182 eV, in subsequent collisions with the surrounding H2 molecules, the μp is quickly de-excited and accelerated by ∼ 2/3 of the excitation energy. The observable is the time distribution of the K-lines X-rays emitted from the μZ formed by muon transfer (μp) + Z → (μZ)* + p, a reaction whose rate depends on the μp kinetic energy. The maximal response, to the tuned laser wavelength, of the time distribution of X-ray from K-lines of the (μZ)* cascade indicate the resonance. During the preparatory phase of the FAMU experiment, several measurements have been performed both to validate the methodology and to prepare the best configuration of target and detectors for the spectroscopic measurement. We present here the crucial study of the energy dependence of the transfer rate from muonic hydrogen to oxygen (Λμp → μ0), precisely measured for the first time.
A silicon-tungsten sampling imaging calorimeter has been designed and built for the PAMELA satellite-borne experiment. The main physics goals of the experiment are the measurement of the flux of ...antiprotons (80
MeV–190
GeV) and positrons (50
MeV–270
GeV) in the cosmic radiation. The calorimeter has been designed to identify antiprotons from an electron background and positrons in a background of protons with a high efficiency and rejection power. This work presents the electron–hadron separation capabilities of the calorimeter as obtained using both Monte Carlo and test beam data. The calorimeter is found to have sufficient performance to reach the primary scientific objectives of PAMELA, providing a proton rejection factor of ∼10
5 while keeping a ∼90% efficiency in selecting electrons and positrons. From simulations, an electron rejection factor of ∼10
5 in antiproton measurements (∼90% antiproton identification efficiency) is demonstrated.
The PAMELA space experiment Menn, W.; Adriani, O.; Barbarino, G.C. ...
Advances in space research,
01/2013, Volume:
51, Issue:
2
Journal Article
Peer reviewed
Open access
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 (100MeV to 100’sGeV) 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 4years 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.
In this work the results of data analysis of the deuteron albedo radiation obtained in the PAMELA experiment are presented. PAMELA is an international space experiment carried out on board of the ...satellite Resurs DK-1. The high precision detectors allow to register and identify cosmic ray particles in a wide energy range. The albedo deuteron spectrum in the energy range 70 – 600 MeV/nucleon has been measured.
PDF
