The production of the elements Li, Be, B by galactic cosmic rays in space and its relation with stellar observations.

The L-element (Li, Be, B) contamination rate of the interstellar gas by nuclear reactions induced by the Galactic Cosmic Rays (G. C. R.) is calculated using a diffusion model of fast moving particles in the Galaxy. The presence of helium in the G. C. R. flux and in the interstellar gas is taken into account. It is found that most of the stellar and meteoritic data is in agreement with a model which otherwise gives a reasonable account of the G. C. R. observations. This model assumes an injection spectrum in total energy power (w-8.6) diffusing in a leaking galaxy with an escape range of 6.3 g cm-8. The intensity, the composition at the source and the spectral shape have remained the same for the last 1010 years. However a large part of the 7Li must come from another source. Two possibfflties are discussed: a) thermonuclear 7Li ejected from Giant Stars in "dirty" regions of our Galaxy, b) spallative Li generated from an intense low energy component of the G. C. R. The relative merits of both hypotheses are discussed. Key words: galactic cosmic rays - Li, Be and B abundances - interstellar gas.