New possibilities for primary cosmic ray investigation at Chacaltaya

The characteristics of EAS with energies of 10 4 -10 6 GeV are calculated with help the of the CORSIKA 5.62 code for the observation level 536 g cm -2 . The new shower selection parameter α e (r 0 ) was defined by taking into account the detector displacement described in the recent HECRE proposal for Chacaltaya. As proven before, the EAS selection with α e (r 0 ) = const gives the possibility to select constant efficiency showers with given energies not dependent on the atomic number of the initiating primary particle. Similar results could be obtained by selecting showers with a constant value of the Cerenkov light flux at distances of ∼ 200 m from the axis pQ (200 m) = const. This way it is possible to obtain unbiased information about the mass composition and energy spectrum of the primary cosmic radiation at energies of 10 4 -10 6 GeV by selecting EAS with α e (49 m) = const and applying extended complex analysis of the electron and muon components and Cerenkov light flux at the Chacaltaya observation level. The experimental reception noise was taken into account in the performed analysis.