Elemental abundance measurements of Zn, Ga, and Ge from the Cosmic Ray Isotope Spectrometer (CRIS) experiment on the Advanced Composition Explorer (ACE) satellite

We have measured the elemental abundances of galactic cosmic-ray Zn, Ga, and Ge using the CRIS instrument on the NASA-ACE spacecraft. These ultra-heavy (Z$>$29) nuclei are very rare and require an instrument with a large geometrical factor, such as CRIS possesses, exposed over a long period of time to collect a significant sample. Over the 10+ years since launch in 1997 we have collected $\sim $250 nuclei with Z$>$29.~ Abundances for these elements measured over the energy range of $\sim $150 to 600 MeV/nucleon will be presented and implications for the nature of the cosmic ray source will be discussed.