Abundances and Spectra for Cosmic-Ray Nuclei from Li to Fe For 2to 150 GeV/n

Journal Article · Mon Mar 27 04:00:00 EST 1978 · Astrophysical Journal

OSTI ID:893057

Orth, Chalres D; Ruffington, Andrew; Smoot, George F; Mast, Terry 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 to 150 GeV/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 4 1/2 {+-} 1/2 g cm{sup -2} for all propagation models. The abundances of all elements above 10 GV/c are consistent with an interstellar pathlength decreasing with rigidity as R{sup -n} with an index n = 0.6{sub -0.3}{sup +0.4}. 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 energy-independent, 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: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Science
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 893057
• Report Number(s): LBL--7553
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: pt1 Vol. 226; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DIFFUSION
ENERGY SPECTRA
IONIZATION POTENTIAL
MAGNETIC SPECTROMETERS
NUCLEI
NUCLEONS
PHOSPHORS
SPARK CHAMBERS
SPECTRA