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The new type of EAS array consisting of EN-detectors possesses the ability to discriminate the composition of cosmic rays. At the Yangbajing Cosmic Ray Observatory, the PRISMA-16-YBJ array has been running for three years. We installed 16 so-called "sand cubes" with one cubic meter size, and compared the data obtained by placing PRISMA-16-YBJ on and away from the sand cubes to study the influence of target material, which is a major environmental factor, on the performance of the array. [ABSTRACT FROM AUTHOR]

Ground extensive air shower experiment is powerless for detecting cosmic ray particles of tens-GeV energy in the GRBs (Gamma Ray Burst) so far, because of its threshold energy. The experimental altitude needs to be increased in order to achieve more effective observation. In this study a water Cherenkov detector prototype based on the single-particle counting technology was constructed to detect GRBs at an altitude of 3,650 m. The preliminary test results show that the detector made in this study has stable performance and can detect cosmic rays. If it is placed at an altitude of approximately 5,200 m, the GRBs with tens-GeV of energy can hopefully be detected. [ABSTRACT FROM AUTHOR]

The measurement of thermal neutrons generated by cosmic ray extensive air showers (EAS) on the Earth's surface provides a new method for studying the composition and energy of cosmic rays with energy in the so-called "knee" region. Given the success of the PRISMA-YBJ array, a new type of thermal neutron detector array was installed at the high-altitude cosmic ray observatory in Yangbajing, Tibet. The array consists of 16 EN-detectors and utilizes a new type scintillator based on a compound alloy of ZnS(Ag) and B2O3 with natural boron. This report describes the deployment of the detector array and its operational results. [ABSTRACT FROM AUTHOR]