Proton Component of the Primary Cosmic Radiation

The proton component has been extensively studied at high altitudes on a series of 6 Skyhook balloon flights at various latitudes using the C Cerenkov-scintillation counter technique. The intensity of primary protons has been measured at 4^, 41^, 53^, and 55^ geomagnetic latitude. The proton differential energy spectrum has been measured directly in the region 250-750 Mev. It is observed that primary alphas and protons have the same form of rigidity spectrum from 1 Bv to 17 Bv. A series of cutoff rigidities are measured in the vicinity of =53^ and 55^. The intensity and composition of fast splash albedo is determined at =4^, 53^, and 55^. Significant time variations are observed between the three high-latitude flights. Differences observed in the intensity and energy spectra of these three flights are discussed and strong restraints are placed on possible modulating mechanisms.