Jul 12 – 23, 2021
Europe/Berlin timezone

Measurement of muon contents in cosmic ray shower with LHAASO-KM2A around knee region

Jul 14, 2021, 6:00 PM
1h 30m


Talk CRI | Cosmic Ray Indirect Discussion


Dr Hengying Zhang (Shandong University)


The number of muons observed at the ground from air showers is sensitive to the mass composition of cosmic ray. Large High Altitude Air Shower Observatory is a hybrid extensive air shower array and the KM2A is a sub-array covering an area of 1 km$^2$, consisting of electromagnetic detectors and muon detectors, can measure the muon content and shower size of the air shower simultaneously with high precision for cosmic rays in the knee region. The muon detector of the KM2A is the most powerful muon detector in the current cosmic ray observatory on the ground. In this paper, the experimental data is recorded by the KM2A in 2020. The mean number of muons in air shower is measured by analyzing the signal of muon detectors for the cosmic ray from hundreds of TeV to tens of PeV, where the energy is reconstructed with the shower size and muon number which is weakly dependent on the components of cosmic ray. We investigate the ability to identify cosmic ray components using muon content. Based on the constant intensity cut method, the muon attenuation length is derived by fitting the muon number with same flux in different zenith angle. The relation between attenuation length and muon number in the shower is studied also. In addition, the experiment data in muon abundance is compared with the simulation results of proton and iron. The mean logarithmic mass of the cosmic ray derived from the mean number of muons in same energy interval, together with the mean mass of supposed spectra, are presented with systematic errors from the energy scale and hadronic model.


LHAASO-KM2A; cosmic ray; muon content; mean mass; knee region

Collaboration Lhaaso
Subcategory Experimental Results

Primary authors

Dr Hengying Zhang (Shandong University) Liping Wang (Shandong University) Xiaoting Feng (Shandong University)


Presentation materials