Cosmic-ray energy spectra between 10 and several hundred GeV per atomic mass unit for elements from Ar-18 to Ni-28 - Results from HEAO 3

Data from the Heavy-Nuclei Experiment (HNE) flown on HEAO 3 are used to determine the abundances relative to <SUB>26</SUB>Fe of the individual elements <SUB>18</SUB>Ar, <SUB>19</SUB>K, <SUB>20</SUB>Ca, <SUB>21</SUB>Sc, <SUB>22</SUB>Ti, <SUB>23</SUB>V, and <SUB>28</SUB>Ni as a function of energy from 10 to several hundred GeV per amu. It is shown that the primary elements Ni and Fe have nearly constant relative abundances over the interval 10 to ≡500 GeV per amu. While this result implies an energy-independent source composition over this energy interval, it appears that the Ni/Fe ratio at these high energies is appreciably larger than that at ≡1 GeV per amu. Individual secondary elements, which are derived principally from interactions of primary Fe nuclei, display a power-law decrease in relative abundance up to ≡150 GeV per amu.