Extensive Penetrating Cosmic Ray-Showers

Abstract

The density spectrum of the particles in Auger showers capable of penetrating twenty centimeters of lead has been measured at 3026-meters elevation, and found to be very nearly the same as the density spectrum of the soft component of the showers, the ratio of penetrating to soft particles apparently decreasing slowly with increasing shower density. This ratio has been measured, using the coincidences between four trays of Geiger counters, all shielded by twenty centimeters of lead, and found to be about 2.3 percent. As this value is considerably higher than the value found by other methods, some calculations on the structure of Auger showers are given, in an attempt to explain the discrepancy. It is found that any experiment using coincidences between unshielded trays, horizontally separated by a few meters, is biased strongly toward recording only the cores of the extensive showers. A cloud chamber, tripped by extensive shower counters, is used to study the structure of the extensive showers, and local production of penetrating particles in lead plates within the chamber is definitely established.