Cosmic-ray spectra of primary protons and high altitude muons deconvolved from observed atmospheric gamma rays

Abstract

We have observed atmospheric gamma rays from 30GeV to 8TeV, using emulsion chambers at balloon altitudes, accumulating the largest total exposure in this energy range to date, SOT ~ 6.66m^2.sr.day. At very high altitudes, with residual overburden only a few g/cm^2, atmospheric gamma rays are mainly produced by a single interaction of primary cosmic rays with overlying atmospheric nuclei. Thus, we can use these gamma rays to study the spectrum of primary cosmic rays and their products in the atmosphere. From the observed atmospheric gamma ray spectrum, we deconvolved the primary cosmic-ray proton spectrum, assuming appropriate hadronic interaction models. Our deconvolved proton spectrum covers the energy range from 200GeV to 50TeV, which fills a gap in the currently available primary cosmic-ray proton spectra. We also estimated the atmospheric muon spectrum above 30GeV at high altitude from our gamma-ray spectrum, almost without reference to the primary cosmic rays, and compared the estimated flux with direct muon observations below 10GeV.

13pages, 11 figures. Accepted for publication in PRD

References in corpus (11)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• Measurements of the Solar Neutrino Flux from Super-Kamiokande's First 300 Days
• EGRET Observations of the Extragalactic Gamma Ray Emission
• A new determination of the extragalactic diffuse gamma-ray background from EGRET data
• Precise Measurement of Cosmic-Ray Proton and Helium Spectra with the BESS Spectrometer
• Flux of Atmospheric Neutrinos
• Measurements of Primary and Atmospheric Cosmic-Ray Spectra with the BESS-TeV Spectrometer
• The Cosmic-Ray Proton and Helium Spectra measured with the CAPRICE98 balloon experiment
• Measurements of Proton, Helium and Muon Spectra at Small Atmospheric Depths with the BESS Spectrometer
• Atmospheric gamma-ray observation with the BETS detectorfor calibrating atmospheric neutrino flux calculations
• A new measurement of the altitude dependence of the atmospheric muon intensity

Cited by in corpus (3)

• Study of cosmic ray interaction model based on atmospheric muons for the neutrino flux calculation
• Observations of High Energy Cosmic-Ray Electrons from 30 GeV to 3 TeV with Emulsion Chambers
• Atmospheric Electron Spectrum above 30 GeV at the high altitude