Diurnal Variation of Cosmic Rays

Abstract

The intensity of cosmic rays at an altitude of 3900 meters was measured hourly over a consecutive period of 240 hours. The procedure eliminated the effects due to the variations of the temperature and possible variations of pressure of the gas in the chamber. The ionization was about 1.5±0.25 percent more between 8 A.M. and 4 P.M. than between 8 P.M. and 4 A.M. If the variation is due to the soft component of the cosmic rays, these results are in satisfactory agreement with the results of other observers. Analysis of the data suggests that the portion of the space in the neighborhood of the sun may emit cosmic rays more copiously than the remote regions. This makes doubtful the inference that the energy in the universe in the form of cosmic rays is comparable with that in the form of light.