The Isotopic Composition of Galactic Cosmic Ray Li, Be and B
Abstract
New measurements are reported of the isotopes of cosmic-ray Li, Be, and B and of the elements C, N, and O, with cosmic ray telescopes on board the IMP-7 and IMP-8 satellites during 1973-74 in the energy range 35-210 MeV/nucleon. High mass resolution and stability together with a set of data more extensive than in previous experiments lead to a clear isotopic separation. The measured isotopic and chemical abundances provide a stringent test for models of interstellar propagation and solar modulation. We find not only that for a steady state propagation and solar modulation model all light isotopes and medium element abundances are explained by 5 g/sq cm average pathlengths, as was earlier found from element analysis, but that also these results, taken along with our Be-10 measurements, indicate a longer lifetime for cosmic rays than predicted by the usual assumption of an average interstellar density of 1 to 3 atoms/cu cm.
- Publication:
-
International Cosmic Ray Conference
- Pub Date:
- August 1975
- Bibcode:
- 1975ICRC....1..325G
- Keywords:
-
- Abundance;
- Cosmic Rays;
- Galactic Radiation;
- Isotope Effect;
- Beryllium Isotopes;
- Boron Isotopes;
- Carbon Isotopes;
- Explorer 47 Satellite;
- Explorer 50 Satellite;
- Isotope Separation;
- Lithium Isotopes;
- Nitrogen Isotopes;
- Oxygen Isotopes;
- Tables (Data);
- Space Radiation