Cloud chamber evidence for the presence of simultaneous high energy nuclear-active particles at mountain altitudes

Abstract

In an examination of twenty two thousand pictures of penetrating showers recorded with a multiplate cloud chamber, (60 cm×60 cm×20 cm), in a time of operation of 5310 hours, at an altitude of 2.2 km, thirtytwo cases have been obtained in each of which two or more simultaneous parallel high energy nuclear-electromagnetic cascades, (∼100 GeV), are seen developing in the plates of the chamber. The visible energy of the individual cores has been determined by the track length method. It is found that in most of the cases the visible energies of the parallel cascades in a picture are of comparable magnitude. The separation between the cores ranges from 5 to 40 cm, and the corrected distribution looks flat. There is clear indication that about half of the events are associated with dense air showers. The « unassociated » events have been interpreted in terms of local nuclear interactions of particles of energy > 450 GeV in air up to a height of 140 meters above the apparatus. The « associated » events have been explained as being parts of air showers containing about 100 nuclear-active particles of energy > 100 GeV near the core.