Deuterium and 3He in cosmic rays

Observation of a large flux of antiprotons in cosmic rays prompted many to postulate new ideas relating to the origin and propagation of cosmic rays in the Galaxy, within the frame work of the secondary hypothesis. Under this hypothesis, cosmic rays traverse a large amount of matter either in the source region or in the interstellar space. As a result, large amount of deuterium and ³He are also produced as a consequence of spallation of helium and heavier nuclei. In this paper we derive the spectra of these isotopes using various models for the propagation of cosmic rays and compare with the existing observations.