Chapter 3 - Cosmic Rays at Sea Level

Abstract

This chapter presents the data of cosmic ray particles at sea level. These include charged hadrons, neutrons, gamma rays, electrons, muons, nuclei and antinucleons. The material is presented in this sequence. The flux of nuclei at sea level is almost nonexistent compared to higher altitudes. A separate section is devoted to this subject to summarize the scant information available and is of theoretical nature.. The probability of surviving from the point of production to sea level depends on the particle type, its charge state, energy, zenith angle of propagation, and mean life at rest. Another important component is neutrinos of all kinds. However, because of their small cross section and weak interaction behavior, and major background problems, no cosmic ray neutrino experiments has been carried out in the atmosphere or at sea level. Since the neutrino flux is not significantly different underground as compared to sea level, the neutrino component is studied exclusively deep underground, underwater or under ice, to insure sufficient shielding and adequate background reduction. The different nature of the problems involving atmospheric neutrinos is discussed in the chapter.