Abundances of Cosmic Ray Nuclei for 26 ≤ Z ≤ 40 From HEAO-3 Heavy Nuclei Experiment

Individual elements in the cosmic radiation of even atomic number (Z)in the interval 26≤ Z ≤ 40 have been resolved and their relative abundances measured. The results are inconsistent with a cosmic-ray source whose composition in this charge interval is dominated by r-process nucleosynthesis

Implications of Ultraheavy Cosmic-Ray Source Composition Derived from Observations by the HEAO-3 Heavy Nuclei Experiment

We have derived the contribution of r-process and s-process nucleosynthesis to the Cameron (1980) solar system (SS) abundances for Z~33. In the interval 34 ~Zs; 40 our HEA0-3 data extrapolated to the cosmic-ray source (CRS) fit the solar system mix better than r-process. In the interval 26 < Z < 40 the HEA0-3 results for CRS/SS follow the same general correlation with first ionization potential as for the lighter eiements although there are deviations in detail

Cosmic Ray Abundances of Sn, Te, Xe, and Ba Nuclei Measured on HEAO 3

Elements with even atomic number ( Z) in the interval 50 ~ Z ~ 56 have been resolved in the cosmic radiation using the Heavy Nuclei Experiment on the HEAO 3 satellite. The observation that 50Sn and 56Ba are more abundant than 52Te Elements with even atomic number ( Z) in the interval 50 ~ Z ~ 56 have been resolved in the cosmic radiation using the Heavy Nuclei Experiment on the HEAO 3 satellite. The observation that 50Sn and 56Ba are more abundant than 52Te and 54Xe is inconsistent with a purer-process cosmic-ray source. Adjustment of source abundances for an enhancement of those elements with a low first ionization potential does not change this conclusion and 54Xe is inconsistent with a purer-process cosmic-ray source. Adjustment of source abundances for an enhancement of those elements with a low first ionization potential does not change this conclusion

Cosmic-ray abundances of elements with atomic number 26 ≤ Z ≤ 40 measured on HEAO 3

Individual elements in the cosmic radiation of even atomic number (Z) in the interval 26 ≤ Z ≤ 40 have been resolved and their relative abundances measured. The results are inconsistent with a cosmic-ray source whose composition in this charge interval is dominated by r-process nucleosynthests. The ratios of cosmic-ray source abundances to solar system abundances in this interval follow the same general correlation with first ionization potential as for the lighter elements although there are deviations in detail

Energy Spectra of Ultraheavy Cosmic Rays Results from HEAO-3

The HEAO-3 Heavy Nuclei Experiment measures cosmic-ray energy directly in the interval 400 to ~1200 MeV/amu. Geomagnetic cutoffs can also be derived up to ~15 GV. We present preliminary rigidity spectra of various ultraheavy cosmic-ray elements relative to iron

The Non-Z^2 Response of the Heavy Nuclei Cosmic Ray Detector on HEAO-3

A combination of ion chambers and Cerenkov radiators similar to the Heavy Nuclei Experiment flown on HEAO-3 was calibrated at the Bevalac heavy-ion accelerator using beams of Mn-25 nuclei at kinetic energies up to about 1700 MeV/nucleon and Au-79 nuclei up to about 1000 MeV/nucleon. The data show only a small deviation (about 2-3 charge units at Au) from the Z^2 scaling used previously (Binns et al., 1981, 1982, 1983) to analyze the HNE data. Although at lower energy, the calibration indicates that the published relative abundances of the _(50)Sn/_(56)Ba group and the published upper-limit actinide abundances are not likely to be significantly affected by non-Z^2 effects

The abundance of the actinides in the cosmic radiation as measured on HEAO 3

The HEAO 3 detector of heavy cosmic-ray nuclei has observed one possible actinide nucleus and some 100 nuclei of the platinum-lead group of elements. The resulting upper limit of 3% for the abundance ratio of actinides to platinum-lead nuclides is significantly lower than previous results from other observations. This new limit is inconsistent with freshly synthesized, pure r-process sources for cosmic-ray nuclei in this charge interval but is consistent with a source having a composition similar to the solar system, or to aged r-process material. We observe no events with a charge greater than 96

Abundances of Cosmic Ray Nuclei Heavier than _(50)Sn

Preliminary results are reported from 430 days of exposure of the heavy nuclei experiment on the HEAO-3 spacecraft. These results are confined to the heavy nuclei with Z ≥ 50 and emphasize the conclusions obtained on the relative numbers of actinides and heavy stable elements in the lead-platinum region. The extreme paucity of actinides found is inconsistent with the predictions of a cosmic ray source that is highly enriched in r-process material, but quite consistent with a source whose composition is similar to that of normal solar system material. An upper limit, at the. 95% confidence level, is placed in the ratio of nuclei with Z ≥ 88/(74 ≤ Z ≤87) of 0.03

Cosmic-Ray Abundances of the Even Charge Elements from _(50)Sn to _(58)Ce Measured on HEAO-3

Elements with even atomic number (Z) in the interval 50 ≤ Z ≤ 58 have been resolved in the cosmic radiation using the Heavy Nuclei Experiment on the HEAO-3 satellite. The observation that _(50)Sn and _(56)Ba are more abundant that _(52)Te and _(54)Xe indicates a substantial s-process contribution to the cosmic ray source. A significant abundance of _(58)Ce provides further support for this finding

Primary Proton Spectrum of Cosmic Rays measured with Single Hadrons

The flux of cosmic-ray induced single hadrons near sea level has been measured with the large hadron calorimeter of the KASCADE experiment. The measurement corroborates former results obtained with detectors of smaller size if the enlarged veto of the 304 m^2 calorimeter surface is encounted for. The program CORSIKA/QGSJET is used to compute the cosmic-ray flux above the atmosphere. Between E_0=300 GeV and 1 PeV the primary proton spectrum can be described with a power law parametrized as dJ/dE_0=(0.15+-0.03)*E_0^{-2.78+-0.03} m^-2 s^-1 sr^-1 TeV^-1. In the TeV region the proton flux compares well with the results from recent measurements of direct experiments.Comment: 13 pages, accepted by Astrophysical Journa