The high–energy muon flux at sea level up to 10 TeV derived from an observation of the burst-size spectrum

Bursts produced by high-energy muons in rock have been observed at a depth of 40 m.w.e. underground by the use of two layers of scintillator 20 m2 in area and 2 m apart. The size distribution of bursts with several hundreds to 30 000 relativistic particles was obtained during an observing time of 11 424.13 hours. Following the method of Christy and Kusaka (1941), the energy spectrum of muons up to 10 TeV was derived from the burst-size distribution.