The neutron-rich isotopes of cosmic-ray neon and magnesium

Journal Article · Fri Aug 15 04:00:00 EDT 1980 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/183322· OSTI ID:6735667

Freier, P S; Young, J S; Waddington, C J

A balloon-borne detector flown during the period of minimum activity in the last solar cycle has been used to observe the isotopes of Ne, Na, Mg, and Al in the cosmic radiation, over an energy range approx.390--530 MeV/n. The detector has a mass resolution of 0.4--0.55 amu in this charge range and was calibrated in flight by fast particles. While the Al and Na nuclei are consistent with essentially pure /sup 23/Na and /sup 27/Al beams, both Ne and Mg show appreciable abundances of neutron-rich isotopes. We find relative abundances corrected to the top of the atmosphere for /sup 20/Ne:/sup 21/Ne:/sup 22/Ne of 57:17:26 and for /sup 24/Mg:/sup 25/Mg:/sup 26/Mg of 59:21:20. The neon abundances are in good agreement with those found from three different satellite experiments. The abundances of magnesium are more controversial, and these measurements add evidence that magnesium is also neutron rich. Our ability to reproduce the neon abundances found by others enhances our confidence in the measurement of magnesium, but the statistical weight is still marginal. These abundances, corrected for interstellar propagation, appear significantly different from those of solar-system material, and reflect the special nature of the cosmic-ray sources.

• Research Organization: School of Physics and Astronomy, University of Minnesota, Minneapolis
• OSTI ID: 6735667
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 240:1; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
ALUMINIUM ISOTOPES
BARYONS
COSMIC NUCLEI
COSMIC RADIATION
COSMIC RAY DETECTION
DATA
DETECTION
ELEMENTARY PARTICLES
EXPERIMENTAL DATA
FERMIONS
HADRONS
INFORMATION
IONIZING RADIATIONS
ISOTOPE RATIO
ISOTOPES
MAGNESIUM ISOTOPES
NEON ISOTOPES
NEUTRONS
NUCLEI
NUCLEONS
NUCLEOSYNTHESIS
NUMERICAL DATA
RADIATION DETECTION
RADIATIONS
SODIUM ISOTOPES