Investigation of the zenith angle dependence of cosmic-ray muons at sea level


Angular distribution of cosmic-ray muons at sea level has been investigated using the Geant4 simulation package. The model used in the simulations was tested by comparing the simulation results with the measurements made using the Berkeley Lab cosmic ray detector. Primary particles’ energy and fluxes were obtained from the experimental measurements. Simulations were run at each zenith angle starting from θ = 0° up to θ = 70° with 5° increment. The angular distribution of muons at sea level has been estimated to be in the form I(θ) = I(0°) cosn (θ), where I(0°) is the muon intensity at 0° and n is a function of the muon momentum. The exponent n = 1.95±0.08 for muons with energies above 1 GeV is in good agreement, within error, with the values reported in the literature.

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Special thanks are extended to Dr H Matis at Lawrence Berkeley National Laboratory for providing the PC board. The authors also would like thank Dr B T Tonguc and former graduate students for their help at various stages of the study. This work has been partially supported by the Sakarya University Scientific Research Project Committee Division under contract number 2007/02/02/003. The numerical calculations reported in this paper were performed at TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure).

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Correspondence to MEHMET BEKTASOGLU.

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BEKTASOGLU, M., ARSLAN, H. Investigation of the zenith angle dependence of cosmic-ray muons at sea level. Pramana - J Phys 80, 837–846 (2013).

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  • Cosmic muon
  • angular dependence
  • Geant4


  • 14.60.Ef
  • 96.50.S−
  • 13.85.Tp