The Altitude and Angular Dependence of Cosmic-Ray Air Showers

Abstract

The angular distribution of the axes of large air showers incident upon a typical coincidence counter detector has been computed in detail from the altitude dependence.The distribution may be approximated by the function cos 5>5 0 at 3500 meters elevation and by cos 7 -5 0 at sea level. These distributions have been tested experimentally by comparing the rates of horizontally and vertically oriented counters. The vertical-horizontal counting ratio (R) was measured to be 2.12±0.07 at 3500 meters, and 2.68±0.07 at sea level. Values of R calculated from the above angular distributions are somewhat higher. The difference is attributed principally to scattering of shower particles about the primary axis.

Observations on the Penetrating Component of Extensive Air Showers

“…The direction of the penetrating [L-mesons in air showers should be close to that of the shower axis, but Brown and McKay (1949) and Sitte (1950) working at mountain altitudes found broader zenith angle distributions for the penetrating particles than for the shower electrons at the same altitudes. The present distribution for the penetrating [L-mesons is in agreement with that expected for the shower axes as calculated from the altitude dependence of air showers by Kraybill (1954).…”

“…Since they are detected amongst the electrons within tens of metres from the shower core, few of them can have large angular deviations from the direction of the shower axis. Kraybill (1954) has calculated the zenith angle distribution of shower axes at sea-level using experimental data on the altitude dependence of air showers. He obtained a cosine power law with the power n=7 '5, and his result agrees with direct measurements on the electrons at sea-level by Deutschmann (1947).…”

“…Brown and McKay (1949) working at an altitude of 3260 ill found n =3 for all penetrating particles under 15 cm of lead, except those which appeared to have been generated in the lead shield. They found n=5 for the electron component and Kraybill (1954) the shower axes. They suspected that local production of penetrating particles in the lead shield may have broadened the distribution.…”