Cosmic Rays and the Sunspot Cycle: A Large Cosmic-Ray Decrease accompanying the Solar Maximum of 1957

Abstract

Several obsevations of the general cosmic-ray level at balloon altitudes have been made which show a very large decrease in intensity during the spring and summer of 1957 compared with 1955 and 1956. The obsevations are of two types, the first made with a small Geiger counter vertical telescope of stepping power 0.2 g/cm/sup 2/, and the second with a combination of Geiger counter and ionization chamber. The 1957 measuremente were made at latitudes of 51.2 deg , 55.3 deg , and 58.6 deg in June for comparison with the earlier measurements at latitudes from 51.2 deg to 64.2 deg . The vertical particle flux has decreased at all atmospheric depths less than 300 g/cm/sup 2/, and the change increases with decreasing depth until at high altitudes and high latitudes it almost reaches a factor of two. (W.D.M.)