The energy spectrum of all-particle cosmic rays around the knee region observed with the Tibet-III air-shower array

We have already reported the first result on the all-particle spectrum around the knee region based on data from 2000 November to 2001 October observed by the Tibet-III air-shower array. In this paper, we present an updated result using data set collected in the period from 2000 November through 2004 October in a wide range over 3 decades between 1014 and 1017 eV, in which the position of the knee is clearly seen at around 4 PeV. The spectral index is −2.68 ± 0.02(stat.) below 1 PeV, while it is −3.12 ± 0.01(stat.) above 4 PeV in the case of QGSJET+HD model, and various systematic errors should be carefully done in the very near future.