Cosmic-Ray Particles

Abstract

Specific Ionization. In a previous experiment, a number of thin straight tracks formed in a Wilson cloud-apparatus were identified as cosmic-ray particle tracks, by means of a Geiger-counter. The specific ionization along these has now been determined and is found not to exceed 36 ion-pairs per cm, in air at 1 atmosphere. This is less than one third the ionization calculated by Kolhörster and Tuwim, whose value is believed to be erroneous, at least for individual tracks, for reasons set forth in this paper.