Energy Spectra of Elements with 18 ≤ Z ≤ 28 Between 10 and 300 GeV/amu

The HEAO-3 Heavy Nuclei Experiment (Binns, et al., 1981) is composed of ionization chambers above and below a plastic Cherenkov counter. We have measured the energy dependence of the abundances of elements with atomic number, Z, between 18 and 28 at very high energies where they are rare and thus need the large area x time of this experiment. We extend the measurements of the Danish French HEAO-3 experiment (Englemann, et al., 19S3) to higher energies, using the relativistic rise of ionization signal as a measure of energy, and determine source abundances for Ar and Ca.