Speaker
Description
The cosmic ray energy spectrum has always been an important tool for investigating fundamental issues related to origin of cosmic rays. The so-called ”knee” around ∼4 PeV, at where the spectral index changes from-2.7 to-3.1, were observed by several experiments. The measurements of the ”knee” by the ground based experiments still have deviations. Most ground-based experiments measure the second particles such as the electromagnetic component and muons in Extensive Air Showers (EAS) to reconstruct the messages of primary cosmic rays, so as Large High Altitude Air Shower Observatory (LHAASO). Electron-Neutron Detector Array (ENDA) was added to measure thermal secondary neutrons generated by high energy hadrons of EAS in conjunction with LHAASO, thereby enhancing the ability to discriminate the mass composition of the primary cosmic rays as well as to understand a stage of the EAS longitudinal development.
In 2023, ENDA was expanded from 16 to 64 detectors so called ENDA-64 in area of 1000 m^2 to measure cosmic rays from 400 TeV to 20 PeV. Coincident events between ENDA-64 and LHAASO are analyzed carefully. In one or two years, we can obtain high statistics of data for studying energy spectrum of light components (H and He) because their hadrons reach observation level at lower energy due to higher energy per nucleon. Hybrid detection by using LHAASO and ENDA can provide a full secondary particle measurement of EAS including electrons, muons, atmospheric Cherenkov light and hadrons which are the main EAS component. In this report, method of data analysis including calibration, data quality check, reconstruction, energy determination and composition separation is described, and results by using full secondary particles are presented.
| Collaboration(s) | on behalf of LHAASO collaboration |
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