ABSTRACT
Cosmic radiation was discovered by Hess in 1912. The composition of a cosmic-ray flux is as follows: (i) nuclear component consist of ∼ 90% protons, ∼ 10% helium nuclei, and ∼ 1% heavier nuclei; (ii) electrons make up ∼ 1% of the nuclei number; (iii) positrons form ∼ 10% of the electrons number; and (iv) the portion of antiprotons is ≥ 10−4 relative to protons. The composition of cosmic rays was experimentally defined in the energy region from few MeV to several TeV [39]. A good agreement between relative occurrences of elements on the Sun and elements in cosmic rays was revealed to point on an unified star mechanism of their production. However, in cosmic radiation, the content of Li,Be, and B nuclei as well as nuclei located immediately before iron are heightened. This excess could be explained assuming the abundance of these elements to have appeared in cosmic rays under motion in cosmic space thanks to spallation reactions on C,N , and Fe nuclei. Then, the ratio of the primary (C,N , and Fe) to secondary (Li,Be, and B) nuclei makes it possible to estimate the time during which cosmic rays are within our galaxy. The result is τ ∼ 106 years. The relative occurrence distribution of elements proves to be almost independent on the energy (except for Fe).
