Measurement of the absolute vertical intensity and momentum spectrum of cosmic-ray muons at sea level of Beijing district

The absolute vertical intensity and momentum spectrum of cosmic-ray muons at sea level of Beijing district has been measured with a range spectrometer composed by a counter telescope system of four large area scintillation counters (two plastic and two liquid scintillators) and a pile of Pb absorber. In addition, a 70 x 50 x 30 cm3 streamer chamber was used as a track detector for shower rejection. The integral spectrum of the momentum was measured from 0.2 GeV/c to 1.3 GeV/c. The integral flux at 0.3 GeV/c is 9.2 x 10-3sr-1cm-2s-1. The ratio of shower rejection is about 30% obtained by scanning streamer tracks from 1.6 x 104 photographs