The work is devoted to the study of a little-studied phenomenon: an increase in X-ray and gamma radiation coming from the atmosphere during precipitation. In this work, attention is focused on the analysis of long-term increase events, which occur rarely and differ from typical increase events in slow growth and the presence of many maxima. A differential spectrum meter for electromagnetic radiation in the range of 0.1–4 MeV is used. An analysis of the spectra measured in long-term increase events showed that the characteristics of the spectra do not differ from the same characteristics in ordinary increases. It is concluded that long-term events do not differ from ordinary ones and are due to the same reasons.

The first results of the operation of a pair of muon telescopes installed at the Apatity and Barentsburg stations (Svalbard) in addition to the existing neutron monitors are presented. A technique for separating small variations against the background of stronger variations caused by solar activity is proposed. With its help, a small anisotropy of cosmic rays between the directions of reception of muon telescopes was revealed. It is still difficult to judge the reasons for such anisotropy, since the period of solar activity is 11 years, and observations were made for just over a year

A portable complex for detecting secondary cosmic ray is developed and built for monitoring cosmic rays during expeditions and in remote locations and lighthouses. The complex contains detectors of neutrons, charged particles, and gamma fluxes. It is tested during expeditions in the Barents and Greenland seas.

The paper reports the results of simulation of cosmic ray proton transport through Earth's atmos-phere. The main objective of this work is to obtain char-acteristics of secondary particle fluxes at different alti-tudes and to convert them to equivalent dose values. The technique for the conversion is based on numerical simulation of interaction between the particles and an anthropomorphic phantom. The paper examines two cases, using a model source of primary proton spectra as input parameters, which correspond to both purely ga-lactic cosmic rays and solar cosmic rays. The computa-tional results are tabulated for the altitude range from 0 km to 11 km above sea level; the upper range value cor-responds to the flight altitude of civilian airliners. These results are shown to agree well with the results obtained by other research teams.

A comparative analysis is performed of data on variations in the electromagnetic component over a solar cycle (SC) to study increases in gamma radiation in different phases of an SC. Variations in the intensity of cosmic rays are detected in Apatity by different detectors for all main components of secondary cosmic rays: nucleonic, electron–muonic, and electromagnetic (gamma radiation).

The Irkutsk 3 cosmic ray station (Mount Khulugaysha, Eastern Sayans, 3000 m) receives an additional neutron monitor section equipped with a high-speed data acquisition system developed at the Polar Geophysical Institute. It is the first time a high-speed data acquisition system is installed at a high-altitude neutron monitor. Characteristics of multiplicity events at lowland and high-altitude stations are compared to reveal substantial differences between multiplicity events.

Results are presented from modeling two different conditions for parameterizing the geometry of Earth’s atmosphere and the spectrum of primary cosmic rays. In the first, the input data correspond to solar cosmic rays and calculations are made for all geographic latitudes and longitudes. The second is devoted to estimating the contribution from the nuclei of galactic cosmic rays while considering only a local region of the atmosphere.

A neutron spectrometer with three energy channels and a particle reception angle of 15° has been developed and installed for joint use with standard detectors at the cosmic ray station in Apatity. This configuration of the device allows one to study the degree of anisotropy of the particle flux. The characteristics of the detector (response function and the angle of reception of particles), as well as the geometric dimensions, were obtained by numerical simulation using the GEANT4 software package. During the operation of the device a database of observations was collected and preliminary results were obtained.

The cosmic ray laboratory of the Polar Geophysical Institute has created a simple and compact telescope with a modular design that is designed to detect ionizing particles in the energy range from 1 MeV to 100 GeV. The telescope consists of two scintillator plates separated by a layer of lead that are located one above the other. The electronic circuit creates a channel for counting the upper detector and a channel of coincidences with the lower one. The area of each detector is 0.25 m2; the average count rate of the upper detector is 3000 pulses/min.

This paper explores the applied use of the RUSCOSMICS software package [http://ruscosmics.ru] designed to simulate propagation of primary cosmic ray (CR) particles through Earth’s atmosphere and collect information about characteristics of their secondary component. We report the results obtained for proton fluxes with energy distributions corresponding to the differential spectra of galactic CR (GCR) and solar CR (SCR) during ground level enhancement (GLE) events GLE65 and GLE67. We examine features of the geometry of Earth’s atmosphere, parametrization methods, and describe a primary particle generator. The typical energy spectra of electrons obtained both for GCR and for GLE65 provide information that allows us to quantitatively estimate the SCR contribution to the enhancement of secondary CR fluxes. We also present altitude dependences of ionization rate for GCR and both the GLE events for several geomagnetic cutoff rigidity values. The conclusion summarizes and discusses the prospects for future research.

An overview is presented of the possibilities of using the module of the RUSCOSMICS software package designed for calculating the passage of cosmic ray (CR) particles through the Earth’s atmosphere. General information on current ways of studying secondary CR fluxes is considered. References are made to works by other groups. Key points of the calculation algorithm are described. Parameterization of initial conditions is analyzed. Typical results obtained in modeling are given. A summary of this work and the outlook for the project are given.