On the Interaction of Cosmic Radiation with Materials at 32 m.w.e. and 200 m.w.e. Underground

Abstract

Penetrating showers produced in lead and some other phenomena have been studied at 32 m.w.e. and 200 m.w.e. below the top of the atmosphere and at sea level with a counter hodoscope. As much cares as possible were taken to avoid uncertainties of the counter hodoscope study. The threshold energy of the penetrating showers observed was estimated as about 7 Bev taking into account the geometrical condition of the apparatus. The cross section for the penetrating showers at 32 m.w.e. was concluded as (2.8±0.7) 10 ^-31 cm ² /nucleon and about ten times bigger cross section was obtained at 200 m.w.e. Those events which were interpreted as the mixed shower coming from the earth above the apparatus were also studied. The energy involved in this phenomena has been estimated to be very high and the cross section was suggested. Occasionally two or more penetrating particles have traversed the apparatus in parallel with each other without being accompanied with soft components. The intimate association of air showers with these events was concluded.