Primary cosmic-ray proton and helium spectra at the knee energy region measured by the Tibet hybrid AS experiment

M. Amenomori, S. Ayabe, D. Chen, S. W. Cui, Danzengluobu, L. K. Ding, X. H. Ding, C. F. Feng, Z. Y. Feng, X. Y. Gao, Q. X. Geng, H. W. Guo, H. H. He, M. He, K. Hibino, N. Hotta, Haibing Hu, H. B. Hu, J. Huang*, Q. HuangH. Y. Jia, F. Kajino, K. Kasahara, Y. Katayose, C. Kato, K. Kawata, Labaciren, G. M. Le, J. Y. Li, H. Lu, S. L. Lu, X. R. Meng, K. Mizutani, J. Mu, K. Munakata, A. Nagai, H. Nanjo, M. Nishizawa, M. Ohnishi, I. Ohta, H. Onuma, T. Ouchi, Shunsuke Ozawa, J. R. Ren, T. Saito, M. Sakata, T. Sasaki, M. Shibata, A. Shiomi, T. Shirai, H. Sugimoto, M. Takita, Y. H. Tan, N. Tateyama, Shoji Torii, H. Tsuchiya, S. Udo, H. Wang, X. Wang, Y. G. Wang, H. R. Wu, L. Xue, Y. Yamamoto, C. T. Yan, X. C. Yang, S. Yasue, Z. H. Ye, G. C. Yu, A. F. Yuan, T. Yuda, H. M. Zhang, J. L. Zhang, N. J. Zhang, X. Y. Zhang, Y. Zhang, Yi Zhang, Zhaxisangzhu, X. X. Zhou



    2 被引用数 (Scopus)


    A hybrid experiment was carried out to study the cosmic-ray primary composition in the 'knee' energy region. The experimental set-up consists of the Tibet-II air shower array( AS ), the emulsion chamber ( EC ) and the burst detector ( BD ) which are operated simulteneously and provides us information on the primary species. For three-year operation, we have observed 177 γ -families ( ∑Eγ 20 TeV ) accompanying air showers with the shower size Ne × 105. Using this data set and a neural network method to select proton and helium induced events, the primary proton and helium energy spectra are obtained between 1015 and 1016. The proton spectrum, thus obtained, can be expressed by a single power-law function with a differential index of -3.01 ± 0.11 and -3.05 ± 0.12 based on the QGSJET+HD and SIBYLL+HD models, respectively, which are steeper than that extrapolated from the direct observations of -2.74 ± 0.01 vin the energy range below (1014eV. Our experiment suggests that the main component responsible for making the knee structure of the all-particle spectrum is composed of nuclei heavier than helium.

    ホスト出版物のタイトル29th International Cosmic Ray Conference, ICRC 2005
    出版社Tata Institute of Fundamental Research
    出版ステータスPublished - 2005
    イベント29th International Cosmic Ray Conference, ICRC 2005 - Pune
    継続期間: 2005 8 32005 8 10


    Other29th International Cosmic Ray Conference, ICRC 2005

    ASJC Scopus subject areas

    • 核物理学および高エネルギー物理学


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