The isotopic composition of cosmic rays with 5 ≤ Z ≤ 26.
Abstract
Results are reported for a high-altitude balloon flight which measured the isotopic composition of cosmic rays by using a Cerenkov-range technique to determine the masses of arriving cosmic rays with charges between 5 and 26 for kinetic energies around 450 MeV/amu. Event-selection criteria are discussed, and the mass-determination technique is outlined. Some of the mass histograms resulting from the analysis are presented along with the mean masses calculated from the data, and the derived isotopic compositions. It is found that: (1) C, N, and O are consistent with pure C-12, N-14, and O-16 sources; (2) Mg seems to require some neutron-rich component at the source; (3) Ne appears to require a source isotopic composition that is even more neutron-rich than the universal abundances; and (4) the source may be somewhat enriched in Fe-54. It is suggested that the fundamental nuclear physics which governed the synthesis of solar-system material may also be responsible for cosmic rays, implying that the solar system is probably an average sample of galactic matter.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1976
- DOI:
- 10.1086/154349
- Bibcode:
- 1976ApJ...205..938F
- Keywords:
-
- Abundance;
- Balloon Sounding;
- Cosmic Rays;
- Isotopes;
- Carbon Isotopes;
- Cerenkov Counters;
- Histograms;
- Iron Isotopes;
- Neon Isotopes;
- Oxygen Isotopes;
- Particle Mass;
- Space Radiation