The Properties of Cosmic Radiation at Very High Altitudes

Abstract

The variation of the vertical cosmic-ray intensity as a function of altitude has been investigated in a series of free-balloon ascents with standardized quadruple-coincidence-counter trains containing various amounts of interposed absorber, to a maximum thickness of 7.5 cm Pb. The curves thus obtained converge at the "top of the atmosphere." A maximum occurs in the curve with 4 cm of Pb, but disappears with 6 cm of Pb. Cosmic-ray absorption curves at various altitudes above that corresponding to an atmospheric pressure of 250 mm of Hg are plotted from the data, as are integral and differential distributions-in-range. The relative stopping powers of carbon and lead are also available from the data.