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

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    2 Citations (Scopus)

    Abstract

    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.

    Original languageEnglish
    Title of host publication29th International Cosmic Ray Conference, ICRC 2005
    PublisherTata Institute of Fundamental Research
    Pages177-180
    Number of pages4
    Volume6
    Publication statusPublished - 2005
    Event29th International Cosmic Ray Conference, ICRC 2005 - Pune
    Duration: 2005 Aug 32005 Aug 10

    Other

    Other29th International Cosmic Ray Conference, ICRC 2005
    CityPune
    Period05/8/305/8/10

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics

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  • Cite this

    Amenomori, M., Ayabe, S., Chen, D., Cui, S. W., Danzengluobu, Ding, L. K., Ding, X. H., Feng, C. F., Feng, Z. Y., Gao, X. Y., Geng, Q. X., Guo, H. W., He, H. H., He, M., Hibino, K., Hotta, N., Hu, H., Hu, H. B., Huang, J., ... Zhou, X. X. (2005). Primary cosmic-ray proton and helium spectra at the knee energy region measured by the Tibet hybrid AS experiment. In 29th International Cosmic Ray Conference, ICRC 2005 (Vol. 6, pp. 177-180). Tata Institute of Fundamental Research.