Abundances and spectra for cosmic-ray nuclei from lithium to iron for 2 to 150 GeV per nucleon

Journal Article · Fri Dec 15 00:00:00 EST 1978 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156692· OSTI ID:6389184

Orth, C D; Buffington, A; Smoot, G F; Mast, T S

We report measurements of the absolute and relative abundances, differential energy spectra, and spectral indices for cosmic-ray nuclei from Li to Fe for 2--150 GeV per nucleon. These measurements were made using a balloon-borne superconducting magnetic spectrometer with scintillators and optical spark chambers. The abundances of Li, Be, and B for rigidities below 10 GV/c are consistent with an energy-independent mean interstellar pathlength of 41/2 +- 1/2 g cm/sup -2/ for the ''leaky-box'' propagation model. The abundances of all elements above 10 GV/c are consistent with an interstellar path length that decreases with rigidity as R/sup -n/ with an index n=0.6(+0.4, -0.3). All differential source spectra can be fitted by power laws in total energy per nucleon with the same spectral index, which is between 2.5 and 2.6 depending on n. If n is near 0.5 (as for simple diffusion), the source index is 2.54 +- 0.03. Relative abundances at the sources are thus independent of energy, and have ratios to solar abundances as a function of first ionization potential which indicate a source temperature between 10/sup 4/ and 5 x 10/sup 4/ K depending on the equilibrium nature of the injection environment.

• Research Organization: Spaces Sciences Laboratory and Lawrence Berkeley Laboratory, University of California, Berkeley
• OSTI ID: 6389184
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 226:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CHEMICAL COMPOSITION
COSMIC NUCLEI
COSMIC RADIATION
ENERGY SPECTRA
FRAGMENTATION
GAS TRACK DETECTORS
INTERSTELLAR SPACE
IONIZING RADIATIONS
MEASURING INSTRUMENTS
NUCLEI
PRIMARY COSMIC RADIATION
RADIATION DETECTORS
RADIATIONS
SCINTILLATION COUNTERS
SPACE
SPARK CHAMBERS
SPECTRA
SPECTROMETERS