Cosmic Rays near the North Geomagnetic Pole in the Summers of 1955 and 1956

Abstract

The experiments herein described are a continuation of similar experiments performed in previous years near the north geomagnetic pole. In 1954 low-energy particles were found at high altitudes which had the characteristics of protons with energies down to 150 Mev. In 1955 flights to higher altitudes (4 g ${\mathrm{cm}}^{-2\mathrm{}}$) indicated that these energies extended down to at least 100 Mev for protons. The numbers of both the high-energy particles ($E>\mathrm{}1\mathrm{}$ Bev) and those of low energy, in 1955 were less than in 1954. On one flight in 1955 the very low-energy particles were missing. In 1956, these low-energy particles (