Measurement of the cosmic ray proton and helium spectrum with energy above 100TeV by the LHAASO experiment

Abstract

Large High Altitude Air Shower Observatory (LHAASO) consists of three interconnected detectors with the aim to measure several air shower characteristics simultaneously. One of the main scientific goals is to measure the individual cosmic ray spectrum at knee regime. In this paper we introduce the progress of measuring the energy spectrum of proton and helium composition of cosmic rays. According to the number of Cherenkov photons recorded by WFCTA, the energies can be reconstructed and the resolution can achieve 15% for showers produced by protons and helium with energies above 300 TeV. Due to the hybrid observation to the air showers, several parameters can be used to identify the mass compositions of the air shower. The ability of LHAASO to identify the mass composition are studied in detail in the paper.