Low-energy muons in extensive air showers at 800 g cm−2

Abstract

The following results on the low-energy (> 0.6 GeV and > 1.0 GeV) muons in air showers of size 105 to 2 × 107 at Ootacamund (800 g cm−2) are obtained: (1) The average total number of muons [Formula: see text] varies as Ne0.32 ± 0.2 for 105 < Ne < 106, and as Ne0.8 ± 0.15for 106 < Ne < 2 × 107. (2) In showers showing flat electron lateral structure, the [Formula: see text] variation with Ne is similar to (1). However, in steep showers, [Formula: see text] varies as Ne0.75 ± 0.15 in the whole size range 105 to 2 × 107. (3) "Muon-rich" showers of size < 106 have less energy in the electron–photon component compared to "normal" showers. No such difference is found for showers of size > 106. (4) There is a slight indication of a deficiency of muon-rich showers having a flat lateral distribution of electrons in the right ascension interval 15–21 hours for showers of size 106–107. A similar deficit of showers was observed by the Tokyo group for muon-rich showers in the same RA interval.