A new study on the energy spectrum and composition of primary cosmic rays at energies ∼ 1014–1016 eV using the GRAPES-3 array at Ooty

Data collected with the 250-detector air shower array and the 560 m2 area tracking muon detector, operated at Ooty in southern India by the GRAPES collaboration, have been analyzed to study the shape of the energy spectrum and the composition around the knee. It is shown that muon multiplicity distributions, observed with the highly modular muon detector, permit a relatively more reliable measurement of the composition of the primary flux which then helps in a more accurate reconstruction of the energy spectrum from the observed shower size spectrum. Some preliminary results are presented here.