Primary Cosmic Ray Energy Spectrum Above the ‘‘Knee’’ Measured with PRISMA-32 Array

Abstract

PRISMA-32 (PRImary Spectrum Measurement Array) is working since 2012 in the Scientific & Educational Center NEVOD (NRNU ‘‘MEPhI’’, Moscow). Array area is ${\sim}500$ m${}^{2}$. PRISMA-32 consists of 32 specially developed electron–neutron detectors capable to measure simultaneously electronic and hadronic components of the extensive air showers with energies above $10^{14}$ eV. This feature is very important because hadronic component is a ‘‘skeleton’’ of the shower, and one can use measurements of hadron number along with simulations to recalculate primary energy spectrum independently or/and together with commonly used EAS size. Detailed Monte-Carlo simulation with CORSIKA and GEANT4 was performed and dependence of hadronic number on primary energy was obtained. Experimental data were processed and analyzed. Primary energy spectrum was recalculated from neutron number spectrum and it is in agreement with some other experiments at energies above $10^{16}$ eV. The results of the analysis are presented.