PAMELA Magnetic Spectrometer Research Articles

Modulation of electrons and positrons in 2006–2015 in the PAMELA experiment

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.

Classification of high-energy antiprotons on electrons background based on calorimeter data in PAMELA experiment

In modern experimental physics a heterogeneous coordinate-sensitive calorimeters are widely used due to their good characteristics and possibilities to obtain a three-dimensional information of particles interactions. Especially it is important at high-energies when electromagnetic or hadron showers are arise. We propose a quit efficient method to identify antiprotons (positrons) with energies more than 10 GeV on electron (proton) background by calorimeter of such kind. We construct the AdaBoost classifier and SVM to separate particles into two classes, different combinations of energy release along reconstructed particle trajectory were used as feature vector. We test a preliminary version of the method on a calorimeter of the PAMELA magnetic spectrometer. For high-energy particles we got a good quality of classification: it lost about 5 · 10−2 of antiprotons, and less than 4 · 10−4 of electrons were classified to antiproton class.

Search for solar neutrons using the data of neutron detector of the PAMELA spectrometer

The study is devoted to the development of the technique for searching for neutrons of solar origin during solar flares using the neutron detector of the PAMELA magnetic spectrometer onboard the RESURS-DK1 satellite. The study of the neutron detector counting rates showed that it operates properly and background conditions are stable in the geomagnetic equator region. 27 solar events from December 2006 to September 2014 were analyzed. Some events contain indications of solar neutron detection. The final conclusion on the nature of these neutrons requires an increase in statistics; to this end, background conditions in polar regions should be analyzed to increase the observation interval.

Trapped positrons observed by PAMELA experiment

Measurements of electron and positron spatial distributions in energy range from 80 MeV to several GeV below the geomagnetic cutoff rigidity were carried out using the PAMELA magnetic spectrometer. The instrument is installed on board the Resurs-DK satellite which was launched June 15th 2006 on an elliptical orbit with the inclination 70 degrees and the altitude 350-600 km. The procedure of trajectories calculations in the geomagnetic filed gives a way to separate stably trapped and short lived albedo components produced in interactions of cosmic ray protons with the residual atmosphere. The work presents spatial distributions of trapped, quasitrapped and short-lived albedo electrons and positrons in the near Earth space. Electron to positron ratio points out on different production mechanism of trapped and quasitrapped particles.

H, He, Li, and Be isotopes in the PAMELA space experiment, according to the flight data of 2006–2008

The results from measurements of the isotopic composition of nuclei from hydrogen to beryllium in galactic cosmic rays observed in the orbital experiment near the solar activity minimum in 2006–2008 by analyzing the loss of nucleus ionization with the rigidity known from measuring the trajectories for particles passed through the device without nuclear interaction in the multilayer calorimeter of the PAMELA magnetic spectrometer are presented. The results from measurements are compared to existing experimental and calculated data.

Observation of the Moon’s shadow in cosmic rays with energies above 400 GeV in the PAMELA satellite experiment

Based on data obtained from satellite in 2006–2009 in the PAMELA experiment, the Moon’s shadow was discovered in cosmic rays with energies above 400 GeV. The obtained results are based on using the method for determining the particle arrival direction in the position-sensitive calorimeter, which is part of the PAMELA magnetic spectrometer. The Moon’s shadow was found to be shifted to the east due to deviations of electrons in the Earth’s magnetic field, which are part of the sample of detected particles.

Solar modulation of galactic cosmic rays with the ARINA and PAMELA spectrometers

Solar modulation of the proton flux in Galactic space radiation during the period from the end of the 23rd to the beginning of 24th cycle of solar activity is investigated using data from the PAMELA magnetic spectrometer and ARINA scintillation spectrometer. The time dependence of proton intensity is plotted, and shows typical features in a form of rises and falls against a main trend. In order to explain these, the correlation between variations in the Galactic proton flux and solar/interplanetary parameters is investigated.

Solar proton events at the end of the 23rd and start of the 24th solar cycle recorded in the PAMELA experiment

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.

H, He, Li, and Be isotopes in the PAMELA experiment

The results from measuring the isotope composition of nuclei from hydrogen to beryllium in Galactic cosmic rays are presented. Data is gathered near the minimum of solar activity in the years 2006–2008 in the orbital experiment by analyzing in the multilayer calorimeter of the PAMELA magnetic spectrometer the ionization losses of nuclei with a rigidity known from trajectory measurements passing through the unit without nuclear interactions. The measurement results are compared to the available experimental and theoretical data.

Solar energetic particle events in 2006-2012 in the PAMELA experiment data

The PAMELA magnetic spectrometer launched in June 2006 has observed the last strong energetic solar particle event of the 23rd solar cycle in December 2006. Subsequent long minimum of solar activity and weak development of the 24th solar cycle led to a deficit in the solar energetic particle events on the Earth orbit. As a result, only few events with protons accelerated above 100 MeV occurred in 2010-2012. The paper gives the preliminary results on energetic solar particles in the beginning of the 24th solar circle as measured with the PAMELA instrument.

Trapped antiprotons in the Earth inner radiation belt in PAMELA experiment

The existence of trapped antiprotons in the Earth’s inner radiation belt has been theoretically predicted, but not observed. We present a procedure for antiproton selection and the observation results from the PAMELA space experiment measurements. The PAMELA magnetic spectrometer ensures reliable identification of particles and charge signs, value determination, and energy measurement, thus enabling us to experimentally establish the existence of antiprotons trapped in the Earth’s inner radiation belt.

Measurement of the high-energy electron and positron spectrum in the PAMELA experiment

The PAMELA magnetic spectrometer onboard the Resurs DK1 satellite no. 1 was put into (Earth) orbit on June 15, 2006; measurements continue at the present time. The scientific objective of the spectrometer is the study of antiproton, proton, positron, electron and light nucleus fluxes in cosmic rays. In this paper, we present the technique for measuring electron and positron spectra in the energy range from 20 to 800 GeV.

A powerful tracking detector for cosmic rays: the magnetic spectrometer of the PAMELA satellite experiment

The WiZaxd-PAMELA detector will be ready within some months to be installed on board of the Russian satellite Resurs-DK1. The satellite will follow, for at least 3 years, a quasi polar orbit with an inclination of 70.4° with respect to the equatorial plane. The experiment will allow the measurement of the antiproton and positron spectra within a wide momentum range and the search for light anti-nuclei in cosmic rays. The detector subsystems have been tested and the final assembly phase is in progress. In this paper we describe the structure of the PAMELA magnetic spectrometer, its current status and some precautions taken to satisfy the requirements of the mission.