D. Podorozhny

Composition and energy spectra of cosmic ray primaries in the energy range 1013 - 1015 eV/particle observed by Japanese-Russian joint balloon experiment

Abstract We report experimental results obtained by the emulsion chambers on board of the long duration balloon. We have been carrying out the trans-Siberian-continental balloon flight since 1995, and the results from 1995 to 1996 experiments are presented here. Total exposure of these two years amounts to 231.5 m 2 h at the average altitude of ∼32 km. The energy range covers 10–500 TeV for proton-primary, 3–70 TeV/n for helium-primary, and 1–5 TeV/n for Fe-group ( Z =26–28), though statistics of heavy components is not yet enough. Our preliminary data show that the spectra of the proton and the helium have nearly the same power indices ∼2.80, while those of heavier ones become gradually harder as the mass gets heavier, for instance the index is ∼2.70 for CNO-group and ∼2.55 for Fe-group. It is remarkable that a very high energy proton with multi-PeV is detected in 1995 experiment, and the estimated flux of this event coincides with a simple extrapolation from the energy spectrum with the power index 2.8 observed in the range 10–500 TeV. It indicates that there is no spectral break at around 100 TeV, in contrast to the maximum energy predicted by the current shock-wave acceleration model. This evidence requires some modification on the acceleration and/or propagation mechanism. Also we present all-particle spectrum and the average primary mass in the energy range 20–1000 TeV/particle. Our preliminary data show no drastic change in mass composition over the wide energy range, at least up to 1 PeV/particle, though the statistics is not yet enough to confirm it concretely. The flight performance and the procedure of the analysis, particularly the energy determination methods and the detection efficiency calculation are also given.

New Universal Cosmic-Ray Knee near a Magnetic Rigidity of 10 TV with the NUCLEON Space Observatory

Data from the NUCLEON space observatory give a strong indication of the existence of a new universal cosmic ray “knee”, which is observed in all groups of nuclei, including heavy nuclei, near a magnetic rigidity of about 10 TV. Universality means the same position of the knee in the magnetic rigidity scale for all groups of nuclei. The knee is observed by both methods of measurement of particles energy implemented in the NUCLEON observatory—the calorimetric method and the kinematic method Kinematic Lightweight Energy Meter. This new cosmic ray knee is probably connected with the limit of acceleration of cosmic rays by some generic or nearby source of cosmic rays.

The Organizational Features of Control, Reception, and Monitoring of Scientific Information in the Nucleon Space Experiment

The NUCLEON experiment is conducted via collaboration of Russian research organizations under the leadership of the Skobel’tsyn Institute of Nuclear Physics. The experiment is aimed at studying the elemental composition and energy spectra of galactic cosmic rays in the ranges of nuclear charges Z = 1–30 and energies of 1011–1015 eV. The research facilities of the experiment were installed on the Resurs-P No. 2 Russian spacecraft as an additional payload. The features of control of the scientific equipment and construction of the computer system responsible for the reception, storage, and quality control of scientific information of the experiment are presented.

Primary and secondary cosmic rays in the NUCLEON space experiment after two years of data acquisition

The NUCLEON space experiment was designed to measure energy spectra of cosmic ray nuclei from protons to iron in the energy range approximately from 1 TeV per particle to 1 PeV per particle with good individual charge resolution. The apparatus started the collection of data at the beginning of 2015 and it is in operation up to now. The duration of the mission is expected to be no less than five years. One of the main feature of the experiment is an implementation of two different methods of energy measurement on board of the apparatus -- the calorimetric method and the new kinematic KLEM method (Kinematic Lightweight Energy Meter). The data obtained after two years of operation are presented. A multiple signs of complex behavior of the nuclei spectra and the ratios of spectra violating of a simple universal power-law behavior of the spectra will be presented in the report.

Measuring the isotopic composition of superheavy nuclei of galactic cosmic rays in the NUCLEON-2 experiment

A brief survey of the data on the isotopic composition of superheavy nuclei in galactic cosmic rays is presented. The scientific goals of the planned experiment are outlined, and the design of the NUCLEON-2 scientific equipment is given.