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Ground level enhancements of cosmic ray intensity registered by means of neutron monitors at middle latitudes were studied by using Student’s criterion. Three of these events on 6 November 1997, 24 August 1998, and 13 December 2006 were analyzed in detail. It is shown that the use of Student’s criterion allows revealing effectively the ground level enhancements at middle latitudes.

Potentialities of a multipurpose astrophysical orbital observatory designed on the basis of ionization-neutron calorimetry for direct studies of energy spectra and charge composition of the primary cosmic radiation in a wide energy range up to the “knee” energies (10 15 –10 16 eV) and other astrophysical goals are considered.

Potentialities of a multipurpose astrophysical orbital observatory designed on the basis of ionization-neutron calorimetry for direct studies of high-energy primary cosmic radiation is considered. Scientific goals of the project are discussed, including measurements of energy spectra and PCR charge composition in a wide energy range up to the "knee" energies (1015 – 1016 eV) as well as a number of other astrophysical goals.

A new complex installation ATHLET is now being built at Tien Shan near Almaty. Some problems of the planned cosmic ray studies are discussed.

A new technique of the Ionization Neutron Calorimeter (INCA) to be installed aboard a satellite or a space station is capable of opening new horizons for cosmic-ray physics. The main goal of the experiment proposed is studying local nearby sources of high-energy cosmic rays by measuring the spectrum and composition of the nuclear component with the energy resolution of better than 30% that is sufficient for solution of these problems in the energy range 0.1–10 PeV, i.e., in the so-called “knee” region, and the spectrum of primary electrons in the energy range 0.1–10 TeV with the proton-background suppression factor up to 107. In addition, this experiment can provide new information on the cosmic-ray gamma-radiation in the energy interval 30 GeV–1 TeV, neutrons and gamma-rays from solar flares, and the existence of very massive exotic charged particles in cosmic radiation. The INCA is a calorimeter combining properties of conventional ionization calorimeters and classical neutron monitors. It can measure both the ionization produced by charged particles and evaporation neutrons arising as a result of excitation of heavy-absorber nuclei by cascade particles. The advantages of the INCA are not only excellent electron–proton separation but a high geometry factor of about 2 m 2 sr / ton owing to the INCA optimized composition and shape, whereas conventional ionization calorimeters are usually limited by geometry factor on the order of 0.1 m 2 sr / ton . To verify the INCA concept, a prototype was constructed and exposed to pion and proton accelerator beams with energies of 4 and 70 GeV, respectively, and to an electron beam with an energy of 200–550 MeV. The experimental data obtained agree well with the results of a Monte Carlo simulation by the SHIELD code.

I. V. AMURINA,1 V. P. ANTONOVA,2 G. M. AUTOVA,3 M. K. BABAEV,4 A. S. BAYGUBEKOV,4 P. F. BEYL’,1 R. U. BEISEMBAEV,1 A. E. BODUNOV-SKVORTSOV,5 A. S. BORISOV,5 K. V. CHERDYNTSEVA,5 A. P. CHUBENKO,5 P. A. CHUBENKO,5 V. G. DENISOVA,5 V. I. DROBZHEV,2 E. N. GUDKOVA,5 A. V. GUREVICH,5 Z. M. GUSEVA,5 E. A. KANEVSKAYA,5 J. KEMPA,6 M. G. KOGAN,5 E. V. KOSTIN,5 O. N. KRYAKUNOVA,2 A. V. KRUGLOV,1 S. V. KRYUKOV,2 M. I. KRYLOWA,1 A. I. KUPCHISHIN,7 A. K. MANAGADZE,8 I. S. MART’YANOV,4 V. M. MAXIMENKO,5 K. M. MUKASHEV,3 R. A. MUKHAMEDSHIN,9 R. A. NAM,1 N. M. NESTEROVA,5 KH. NURITDINOV,10 V. V. OSKOMOV,7 V. P. PAVLYUCHENKO,5 V. V. PISCAL’,1 R. YU. POLYAKOV,1 V. S. PUCHKOV,5 S. E. PYATOVSKY,5 I. V. RAKOBOL’SKAYA,8 T. M. ROGANOVA,8 N. N. ROINISHVILI,11 V. A. RYABOV,5 N. O. SADUEV,7 T. KH. SADYKOV,4 S. B. SHAULOV,5 A. L. SHCHEPETOV,5 S. A. SLAVATINSKY,5 A. V. STEPANOV,1 L. G. SVESHNIKOVA,8 G. T. SHOIYNBAEVA,3 ZH. T. TOLEGEN,7 YU. N. VAVILOV,5 A. V. VARGASOV,5 N. G. VIL’DANOV,1 L. I. VIL’DANOVA,1 V. I. YAKOVLEV,5 T. S. YULDASHBAEV,10 N. N. ZASTROZHNOVA,4 G. T. ZATSEPIN9 and V. V. ZHUKOV1 1Tien Shan Mountain Scientific Station of LPI, Almaty, 480037 Kazakhstan 2Institute of Ionosphere, Ministry of Education and Science, Almaty, 480020 Kazakhstan 3Abai Almaty State University, Almaty, 480100 Kazakhstan 4Physical-Technical Institute of Academy of Sciences of Uzbekistan, Almaty, 700084 Kazakhstan 5P. N. Lebedev Physical Institute, Moscow, 119991 Russia 6Warsaw University of Technology, Warszawska Politechnika, Off-Campus, Plock, 09400 Poland 7Al-Faraby Kazakh National University, Ministry of Education and Science, Almaty, 480012 Kazakhstan 8D. V. Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow, 119899 Russia 9Institute for Nuclear Research, Russian Academy of Sciences, Moscow, 117312 Russia 10Physical-Technical Institute of Academy of Sciences of Uzbekistan, Tashkent, 700084 Uzbekistan 11Institute of Physics Academy of Sciences of the Georgian Republic, Tbilisi, 380077 Georgia