Nuclei In Primary Cosmic Radiation Research Articles

Change in the Mass Composition of Primary Cosmic Radiation at Energies in the Range of $${E_{0}=1}$$–100 PeV According to Data of the KASCADE-Grande Experiment

The change in the fluxes of the lightest and heaviest nuclei in the mass composition of primary cosmic radiation in the energy range of $$E_{0}=1$$ –100 PeV is analyzed on the basis of data from the KASCADE-Grande experiment. This analysis is performed by means of the min–max age ( $$S_{\mathrm{min-max}}$$ ) method for extensive air showers (EAS) that is proposed in the present article. This method makes it possible to estimate the exponents of the spectra for the lightest and heaviest nuclei in the mass composition of primary cosmic radiation and to study irregularities in these spectra at energies $$E_{0}$$ in the range under consideration. The $$S_{\mathrm{min-max}}$$ method for estimating the mass composition of primary cosmic radiation is based on a sizable sample (more than 100 million events) of data on EAS features in the range of $$E_{0}=1$$ –100 PeV from the KASCADE-Grande experiment. It is shown that, in the primary-energy range of $$E_{0}=1$$ –100 PeV, the exponent in the integrated spectrum changes from 2.1 to 2.7 for the lightest nuclei in the mass composition of primary cosmic radiation and from 1.5 to 2.1 for the heaviest nuclei. These results comply with the conclusion drawn by the KASCADE-Grande Collaboration that the knee in the $$E_{0}$$ spectrum of nuclei of primary cosmic radiation in the range of $$E_{0}=3$$ –5 PeV is due to the elimination of light nuclei. The bump appearing in the $$E_{0}$$ spectrum of primary cosmic radiation according to the database of the KASCADE-Grande experiment and lying in the range of $$E_{0}=50$$ –75 PeV is analyzed by the $$S_{\mathrm{min-max}}$$ method and is found to agree with data of the GAMMA (GAMMA-07) experiment.

Estimation of the $$\boldsymbol{p+\textrm{He}}$$ Fraction in the Mass Composition of Primary Cosmic Radiation the Energy Range of $$\boldsymbol{E_{0}=1}$$–100 PeV according to Gamma-Ray Families Featuring Halo

The present article reports on an analysis of the properties that gamma-ray families featuring a halo exhibit in the cores of extensive air showers (EAS). The events under analysis were obtained in the XREC (x-ray emulsion chambers) PAMIR experiment, and the properties of these events were studied at distances extending up to about 10 cm from the EAS axis with a resolution of approximately 30 $$\mu$$ m. The investigation of the parameters of events in EAS cores by the halo method permitted analyzing the mass composition of primary cosmic radiation (PCR) at $$E_{0}=10$$ PeV and assessing the fraction of light nuclei in PCR, which depend only slightly on the model of EAS propagation through the atmosphere. From an analysis of gamma-ray families featuring a halo and multicenter halos obtained in the PAMIR XREC, it was found that the fraction of the ( $$p+\textrm{He}$$ ) component of PCR was about 40 $${\%}$$ . The properties of proton-induced EAS events detected at the Tien-Shan high-mountain Scientific Station (TShSS) were studied along with the KASCADE-Grande experimental data. On the basis of studying the dependence of the EAS age and $$N_{\mu}$$ on $$N_{e}$$ in the TShSS EAS (EAS $$+$$ XREC TShSS) data, it is concluded that PCR mass composition becomes heavier in the range of $$E_{0}=1$$ –100 PeV.

On the estimate of the energy of the nuclei of primary cosmic radiation generating extensive air showers

The analysis of the systematic errors in the determination of the energy of the particles of primary cosmic radiation that are inherent in the method for measuring extensive air showers (EASs) indicates the necessity of the exact inclusion of fragmentation in the nuclear interactions. The application of such a model developed for describing the experiments at the Relativistic Heavy Ion Collider improves the agreement between the energy spectra of the ultrahigh-energy cosmic rays measured at giant EAS arrays. It has been shown that the difference between the measured primary cosmic radiation flux intensities and the energies of the primary particles is within the methodical and instrumental errors. The real accuracy of the EAS method of studying ultrahigh-energy cosmic rays has been estimated using the data from six arrays.

An analysis of high-energy interactions with large transverse momentum of secondary particles

Research into the fluctuation of pseudorapidity distributions of secondary particles, produced in interactions of hadrons and nuclei of primary cosmic radiation at energy values of more than 1 A TeV by the normalized range method is carried out. Results of the analysis allow us to assert that there are events in which considerable multiparticle correlations are observed.

Observations of Fluorine Nuclei in the Primary Cosmic Radiation Made on the Pioneer 8 Spacecraft

Fluorine nuclei in primary cosmic radiation identified by counter telescope measurements on Pioneer 8 spacecraft

Isotopic composition and energy spectrum of low-nergy helium nuclei in primary cosmic radiation

The isotopic composition and the energy spectrum of low-energy helium nuclei have been investigated, using a nuclear emulsion stack flown from Fort Churchill, Canada, on August 4, 1962. The proportion of He3 nuclei at the top of the atmosphere was determined to be 18±5% within the kinetic energy interval of 160–370 Mev/nucleon and 24±8% within the rigidity interval 1.1–1.4 bv/c. The differential energy spectrum in the above energy interval was found to have a maximum around 275–300 Mev/nucleon. Assuming that there is no He3 at the cosmic-ray sources, and that the observed abundance reflects the interactions of the primary radiation in its passage through interstellar matter, we conclude that the low-energy primary radiation has traveled a total of 6±2 g/cm2 in this medium. This result is found to be consistent with the values obtained from the low-energy lithium, beryllium, and boron experiment. The implications of these results are examined on the basis of different models used for the propagation of cosmic radiation through interstellar matter.

Geomagnetic Effects of Heavy Primary of Cosmic Radiation at Geomagnetic Latitude 24°N

The azimuthal distribution of heavy nuclei in primary cosmic radiation is measured by means of orientation-controlled nuclear emulsion stack exposed at geomagnetic latitude 24°N. Assuming that the integral energy spectrum of heavy primaries is represented by \(N({\geqslant}E){=}K(1+E)^{-\gamma}\), the exponent γ is obtained from the azimuthal distribution comparing with geomagnetic cut off theory. The obtained value of γ is 1.26±0.35, and this result agrees with that of Kaplon et al. but not with others. This discrepancy may be interpreted as an effect of the solar activity.

Nuclear Interactions Produced Heavy Nuclei of Primary Cosmic Radiation in Nuclear Emulsions

Fifty-two nuclear interactions produced by the nuclei of cosmic radiation with charge Z =6, 7 and 8, and with energies around 4×10 10 eV/nucleon were studied in nuclear emulsions. The ratio of the number of interactions with heavy nuclei (Ag and Br) to that with light nuclei (H, C, N and O) was found to be 1.03, which is in good agreement with the value calculated by assuming the geometrical cross sections of the colliding nuclei. The features of interactions in which the colliding volume of an incident nucleus was equal to that of an alpha-particle were similar to those of a free alpha-particle. The average number of heavily ionizing tracks, N h , indicated the exponential increase as the impact parameter decreased. The distribution of the total charge of the fragments showed rather regular bumps at even charge. Almost all shower particles ejected with the smallest angles to the primary direction (shower axis) were the nucleons which came from primary nuclei. The angular distribution of mesonic shower pa...

Heavy nuclei in primary cosmic radiation: L. V. Kurnosova, L. A. Razorenov and M. I. Fradkin: (pp. 70–74)

An investigation of primary cosmic radiation composition was conducted to determine the flux of nuclei of large atomic number Z. Previously, there were no reliable data for the number of nuclei with Z > 30 in the primary flux. The relative abundance of these nuclei was found to be small, as predicted. (L.N.N.)

The flux of medium and heavy nuclei in the cosmic radiation near the equator

A determination was made of the fluxes of medium and heavy nuclei in primary cosmic radiation, using a stack of nuclear emulsions over Guarn ( lambda = 40 deg M, at an altitude of 101,000 feet for 7 hrs. The emulsions were scanned for the tracks of heavy nuclei, and a determination of the charge was made by delta -counting. A clear resolution was achieved between particles of the various charge groups. (A.C.)

On the Energy Spectrum of Heavy Nuclei in Primary Cosmic Radiation

On the Energy Spectrum of Heavy Nuclei in Primary Cosmic Radiation

Atomic Nuclei in Primary Cosmic Radiation

IT is generally assumed that the mesotrons in cosmic radiation are produced by primary electrons in the upper atmosphere, but there seems as yet not to be any direct evidence for such a process. On the contrary, experiments by Janossy1 indicate that electrons cannot produce mesotrons with a probability sufficient to account for the intensity of the mesotronic component.