Measurement of cosmic-ray proton and antiproton spectra at mountain altitude

Energy spectra of atmospheric secondary cosmic-ray protons and antiprotons were measured at mountain altitude, 2770 m above sea level. We observed more than <f>105</f> protons and <f>102</f> antiprotons. Our proton spectrum is generally consistent with other previous measurements. The observed antiproton spectrum suggests that the energy loss due to non-annihilation processes is less significant than that assumed in previous model calculations. [Copyright &y& Elsevier]