Читать книгу Muography - Группа авторов - Страница 18

The muons that arrive at sea level are the last stage of a multi‐step cascade process. The average muon energy loss in the atmosphere is in the order of 2 GeV. Therefore, sub‐GeV muons originated in the upper atmosphere cannot reach sea level, and the muon energy spectrum varies at different atmospheric depths; in particular, in energy regions lower than 2 GeV. Based on the results of the CAPRICE 94 muon measurements (Boezio et al., 2000), the low‐energy (< 2 GeV) muon flux increases by a factor of 5 if the atmospheric depth is reduced by one half of the value at sea level (500 hPa) (Engel et al. 2001). On the contrary, the flux of muons with higher energies (3–20 GeV) increases only by a factor of 1.5 (Engel et al. 2001).