Arkady Moiseev Galper

Experiment NINA: investigation of low energy nuclear fluxes in the near-Earth space

Abstract The mission NINA is the first step of a wide scientific program named WiZard-RIM, conceived to make extensive studies on the Anomalous Component and the isotopic composition of the cosmic rays from hydrogen to iron, in the energy range 10–100 MeV/n. NINA is a silicon detector which is going to fly on the Russian Resource 01 n.4 satellite by the end of 1997.

Study of cosmic rays and light flashes on board Space Station MIR: The SilEye experiment

The SilEye experiment aims to study the cause and processes related to the anomalous Light Flashes (LF) perceived by astronauts in orbit and their relation with Cosmic Rays. These observations will be also useful in the study of the long duration manned space flight environment. Two PC-driven silicon detector telescopes have been built and placed aboard Space Station MIR. SilEye-1 was launched in 1995 and provided particles track and LF information; the data gathered indicate a linear dependence of FLF(Hz) ( 4 2) 10(3) 5.3 1.7 10(4) Fpart(Hz) if South Atlantic Anomaly fluxes are not included. Even though higher statistic is required, this is an indication that heavy ion interactions with the eye are the main LF cause. To improve quality and quantity of measurements, a second apparatus, SilEye-2, was placed on MIR in 1997, and started work from August 1998. This instrument provides energetic information, which allows nuclear identification in selected energy ranges; we present preliminary measurements of the radiation field inside MIR performed with SilEye-2 detector in June 1998.

Isotope composition of secondary hydrogen and helium above the atmosphere measured by the instruments NINA and NINA‐2

[1]xa0In this paper we report on the energy spectra and abundance ratios of hydrogen and helium isotopes of albedo origin, measured by the instruments NINA and NINA-2 in near-equatorial regions. The instrument NINA flew on board the satellite Resurs-01-N4 between 1998 and 1999, at a 830 km average altitude. The NINA-2 apparatus, on board the satellite MITA, was put into orbit in July 2000 at an altitude of about 450 km. NINA and NINA-2 measurements revealed that 2H, 3H, 3He, and 4He are a significant portion of the secondary flux above the atmosphere. The energy spectra of hydrogen isotopes are practically flat across the energy range of 10–40 MeV/n, while the spectra of helium isotopes can be fitted by a power law of spectral indexes γ = 0.8 and γ = 1.5 for 3He and 4He, respectively.

Geomagnetically trapped light isotopes observed with the detector NINA

[1]xa0The detector New Instrument for Nuclear Analysis (NINA) aboard the satellite Resurs-01-N4 detected hydrogen and helium isotopes geomagnetically trapped, while crossing the South Atlantic Anomaly. Deuterium and tritium at L shell < 1.2 were unambiguously recognized. The 3He and 4He power law spectra, reconstructed at L shell = 1.2 and B < 0.22 G, have indices equal to 2.30 ± 0.08 in the energy range 12–50 MeV nucleon−1 and 3.4 ± 0.2 in 10–30 MeV nucleon−1, respectively. The measured 3He/4He ratio and the reconstructed deuterium profile as a function of L shell bring one to the conclusion that the main source of radiation belt light isotopes at Resurs altitudes (∼800 km) and for energy greater than 10 MeV nucleon−1 is the interaction of trapped protons with residual atmospheric helium.

Light Isotope Abundances in Solar Energetic Particles Measured by the Space Instrument NINA

This article reports nine solar energetic particle (SEP) events detected by the New Instrument for Nuclear Analysis (NINA) between 1998 October and 1999 April. NINA is a silicon-based particle detector mounted on board the Russian satellite Resurs-01-4, which has flown at an altitude of about 800 km in polar inclination since 1998 July. For every solar event, the power-law 4He spectrum across the energy interval 10-50 MeV nucleon-1 was reconstructed and spectral indexes, γ, from 1.8 to 6.8 extracted. Data of 3He and 4He were used to determine the 3He/4He ratio, which for some SEP events indicated an enrichment in 3He. For the 1998 November 7 event, the ratio reached a maximum value of 0.33 ± 0.06, with spectral indexes of γ = 2.5 ± 0.6 and γ = 3.7 ± 0.3 for 3He and 4He, respectively. The 3He/4He ratio averaged over the remaining events was 0.011 ± 0.004. For all events, a deuterium-to-proton ratio was estimated. An upper limit on the average value over all events was 2H/1H < 4 × 10-5 across the energy interval 9-12 MeV nucleon-1. Upper limits on the 3H/1H counting ratio for all events were determined. For the 1998 November 14 SEP event, the high flux of heavy particles detected made it possible to reconstruct the carbon, nitrogen, and oxygen flux.

Features of the Mechanism of Formation of the Radiation Belt of High-Energy Electrons and Positrons

New results of the PAMELA experiment revealed significant difference in the electron and positrons flux and fraction between trapped particles of the radiation belt and quasitrapped particles. A decrease in the ratio of the electron-to-positron fluxes both with increasing altitude and with decreasing energy was observed for the inner radiation belt, but this does not fit in currently used models. The residual atmosphere density in the trapping region for L ~ 1.15−1.2 is estimated on the basis of calculations of trapped-particle trajectories in the Earth’s magnetosphere. It is shown that processes leading to the energy loss for trapped electrons and positrons in the interactions with residual-atmosphere atoms play an important role in the formation of fluxes of these particles, but these processes cannot cause the reduction of the positron fraction in the total flux at energies below some 100 MeV. The role of the process of δ-electron production in the formation of the belt of trapped electrons and positrons is considered. Allowance for this process makes it possible to explain the above reduction at least partly.

Hardware and software for ground tests of onboard charged particle spectrometers

The article presents a hardware and software complex for ground tests of onboard charged particle spectrometers that are designed at the National Research Nuclear University MEPhI for monitoring of nuclear-physical factors of space weather and can be installed in a wide class of satellites. The structural scheme and operating principles of component parts are discussed. The main algorithm and software features are presented. The technique of ground spectrometer tests and calibrations in various measurement modes at atmospheric cosmic particle flows, both in autonomous laboratories and in interface tests as part of a satellite, is also described.

Measurement of the total spectrum of electrons and positrons in the energy range of 300–1500 GeV in the PAMELA experiment with the aid of a sampling calorimeter and a neutron detector

A method based on the use of a sampling calorimeter was developed for measuring the total energy spectrum of electrons and positrons from high-energy cosmic rays in the PAMELA satellite-borne experiment. This made it possible to extend the range of energies accessible to measurements by the magnetic system of the PAMELA spectrometer. Themethod involves a procedure for selecting electrons on the basis of features of a secondary-particle shower in the calorimeter. The results obtained by measuring the total spectrum of cosmic-ray electrons and positrons in the energy range of 300–1500 GeV by the method in question are presented on the basis of data accumulated over a period spanning 2006 and 2013.

Measurement of the deflection of cosmic-ray electrons in the energy range 75–250 GeV by the Earth’s magnetic field with the PAMELA experiment

The deflection of electrons in the Earth’s magnetic field in the energy range 75–250 GeV (the so-called east-west effect) has been measured with the PAMELA satellite-borne experiment. The results are presented for various L-shells. The data obtained can be used to construct mathematical models that describe the structure of the Earth’s magnetic field and to refine the already existing models. These data can also be directly applied to estimate the positron fraction in cosmic-ray electron fluxes both in the PAMELA experiment and in other satellite-borne experiments.