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Small and middle size surface detectors measuring extensive air showers (EAS) initiated by primary cosmic rays (PCR) incident on terrestrial atmosphere have been in operation for the last 50 years. Their main goal is to explore the ‘‘knee’’ in all particle spectrum to solve the problem of cosmic ray (CR) origin and acceleration. The recent achievements of atmospheric Cherenkov telescopes and X-ray space laboratories, establishing the supernova remnants (SNRs) as a source of hadronic cosmic rays, pose stringent conditions on the quality of EAS evidence. After establishing the existence of the ‘‘knee’’ itself, the most pronounced result from EAS studies is the rigidity dependent shift of the knee position to the highest energies. This feature was first observed by separation of the primary flux in different mass groups in MAKET-ANI, EAS-TOP and KASCADE experiments. The MAKET-ANI detector is placed on Mt. Aragats (Armenia) at 3200 m above the sea level (40� 25 0 N, 44� 15 0 E). More than 1.3 · 10 6 showers with size greater than 10 5 particles were registered in 1997–2004. The detector effectively collected the cores of EAS, initiated by primaries with energies of 10 14 –10 17 eV. After proving that the quality of the EAS size and shape reconstruction was reasonably high, we present the lateral distribution function (LDF) for distances from 10 to 120 m from EAS core and EAS size spectra in 5 zenith angle intervals. We use CORSIKA simulations to present the energy spectra. The results from the MAKET-ANI experiment on the energy spectra of the ‘‘light’’(p + He) and ‘‘heavy’’ (O + Si + Fe) nuclear groups are compared to the spectra obtained by balloon experiments and to other available spectra. � 2007 Elsevier B.V. All rights reserved.

The Aragats Solar Neutron Telescope (ASNT) is in operation at the Mt. Aragats research center (3200 m above sea level) in Armenia and constitutes part of the worldwide network, coordinated by Nagoya University. In this paper, we calculate the response function of the ASNT to the galactic and solar cosmic rays and determine the energy thresholds of the four ASNT channels. The capability of ASNT to distinguish the Ground Level Enhancements (GLEs) originated by solar neutrons is proposed and tested on the largest GLEs of the 23rd solar cycle.

The Aragats Space-Environmental Center provides monitoring of different species of secondary cosmic rays at two altitudes and with different energy thresholds. One-minute data is available on-line from http://crdlx5.yerphi.am/DVIN/index2.php . We present description of the main monitors along with data acquisition electronics. Also we demonstrate the sensitivity of the different species of secondary cosmic ray flux to geophysical conditions, taking as examples the extremely violent events of October–November 2003. We introduce correlation analysis of the different components of registered time-series as a new tool for the classification of the geoeffective (events on earth affected by solar activity) events and for the forecasting of the severity of the upcoming geomagnetic storm.

Standard models of cosmic-ray origin link the space accelerators of our Galaxy to the supernova remnants (SNRs)—expanding shells driven by very fast blast waves, usually with gamma-ray pulsars near the morphological center. Energy spectra of fully stripped ions with charges from Z = 1 to Z = 26 can provide clues to the validity of the standard model. Unfortunately, smeared data from the extensive air shower experiments do not provide enough information for such ion "spectroscopy." Nonetheless, the measurement of energy spectra of two or three broad mass groups (so-called light, intermediate, and heavy) will allow us to prove or disprove the "rigidity-dependent" acceleration. Recently, using multidimensional classification methods, the "all-particle" spectra from the MAKET-ANI experiment on Mount Aragats, in Armenia, was categorized into two distinct primary mass groups. We present, for the first time, the light and heavy nuclei spectra from the MAKET-ANI experiment.

The Aragats Space Environment Center in Armenia provides real-time monitoring of cosmic particle fluxes. Neutron monitors operating at altitudes of 2000 m and 3200 m on Mt Aragats continuously gather data to detect possible abrupt enhancement of the count rates. Additional high precision detectors, measuring muon and electron fluxes, along with directional information have been put in operation on Mt Aragats in the summer of 2002. We plan to use this information to establish an early warning system against extreme solar energetic particle (SEP) events which pose danger to the satellite electronics and the space station crew. Solar ion and proton fluxes as measured by space-borne sensors on ACE and GOES satellites are used to derive expected arrival times of highest energy ions at 1 AU. The peaks in the time series detected by Aragats neutron monitors, coincided with these times, demonstrate the possibility of early detection of SEP events using the ground-based detectors.

The Solar Environment Center located on Mt. Aragats will provide real-time monitoring and forecasting of the extreme Geomagnetic and Radiation Events. Two neutron monitors, a muon telescope and a Solar scintillation telescope operating on Aragats research stations will provide accurate detection of very low fluxes of the most energetic Solar particles and modulation effects of Solar events. The correlation of the Solar Energetic Phenomena with modulations of the Galactic Cosmic Ray flux and direct detection of the high-energy protons and neutrons emitted during Coronal Mass Ejection provide firm grounds for specification and forecasting of the effects of tremendous explosions on the Solar surface. Consequently ground observation of the variations of Cosmic Ray fluxes make it possible to issue alerts to avoid imminent hazard of upcoming Geomagnetic and Radiation Storms.

The results of probing the radiation environment on board different civil aviation planes with singletype detectors (nuclear emulsions), with particular emphasis to the cosmic radiation flux measured inside aircraft, are presented. The measurement results make it possible to find the absorbed and equivalent doses induced by the cosmic radiation neutrons and charged particles.

This paper describes the neutron energy spectra measured inside and outside the Mir space station. The measurements were made during the second half of 1991 with nuclear emulsions and a neutron and recoil proton spectrometer, whose output data was telemetry-transmitted. In the fast-neutron ( E n > 1.0 MeV) range, the measurements were carried out using the method of recoil protons in a stack of nuclear photoemulsions (NPE) and in an organic scintillator. To determine spectra of intermediate-energy resonance neutrons (1.0 MeV ≥ E n ≥ 10 −2 MeV), an attempt was made to use the NPE method by adding lithium salts. The measurements are characterized by long-term (133 days) exposures of passive detectors and by sizeable effective shielding thicknesses of the inside detector estimated to be ∼40 g cm −2 . The experimental results are compared with each other and with the data published elsewhere. The neutron spectra measured are used to calculate the equivalent dose rates inside and outside the Mir station in various neutron energy ranges. The equivalent neutron dose estimated by measuring the spectra in the (1–10 MeV) range only (as done in earlier works) is observed to entail substantial underestimating of the true neutron dose. Comparison is made of the calculated neutron doses with similar calculations of ionizing-radiation doses for shielding thickness of ∼ 40 g cm −2 . It is emphasized that the study should be continued.

The Aragats Space Environmental Center facilities continuously measure fluxes of neutral and charged secondary cosmic ray incidents on the Earth's surface. Since 2003 in the 1-minute time series we have detected more than 100 enhancements in the electron, gamma ray, and neutron fluxes correlated with thunderstorm activities. During the periods of the count rate enhancements, lasting tens of minutes, millions of additional particles were detected. Based on the largest particle event of September 19, 2009, we show that our measurements support the existence of long-lasting particle multiplication and acceleration mechanisms in the thunderstorm atmosphere. For the first time we present the energy spectra of electrons and gamma rays from the particle avalanches produced in the thunderstorm atmosphere, reaching the Earth's surface.

Joint Soviet-American measurements of the neutron component of space radiation (SR) were carried out during the flight of the Soviet biosatellite Cosmos-2044. Neutron flux densities and differential energy spectra were measured inside and on the external surface of the spacecraft. Three energy intervals were employed: thermal (Enor = 0.2 eV), resonance (0.2 eVEn1.0 MeV) and fast (Enor = 1.0 MeV) neutrons. The first two groups were measured with U.S. 6LiF detectors, while fast neutrons were recorded both by U.S. fission foils and Soviet nuclear emulsions. Estimations were made of the contributions to absorbed and equivalent doses from each neutron energy interval and a correlation was presented between fast neutron fluxes, measured outside the satellite, and the phase of solar activity (SA). Average dose equivalent rates of 0.018 and 0.14 mrem d-1 were measured for thermal and resonance neutrons, respectively, outside the spacecraft. The corresponding values for fast neutrons were 3.3 (U.S.) and 1.8 (U.S.S.R.) mrem d-1. Inside the spacecraft, a value of 3.5 mrem d-1 was found.

Two methods for measuring neutrons in the range from thermal energies to dozens of MeV were used. In the first method, alpha-particles emitted from the 6Li(n,alpha)T reaction are detected with the help of plastic nuclear track detectors, yielding results on thermal and resonance neutrons. Also, fission foils are used to detect fast neutrons. In the second method, fast neutrons are recorded by nuclear photographic emulsions (NPE). The results of measurements on board various satellites are presented. The neutron flux density does not appear to correlate clearly with orbital parameters. Up to 50% of neutrons are due to albedo neutrons from the atmosphere while the fluxes inside the satellites are 15-20% higher than those on the outside. Estimates show that the neutron contribution to the total equivalent radiation dose reaches 20-30%.

Radiation environment onboard STS-55 and 57 is estimated using experimental and calculated data.