| This work describes a stepwise program of interstellar cosmic ray propagation that is used to study the sensitivity of propagation models of ultra heavy cosmic ray nuclei (UH nuclei). We have evaluated the uncertainties introduced in the predicted abundances by calculating the fragmentation cross sections using different procedures, by varying the input energy, and by varying the escape length of the cosmic ray nuclei. These uncertainties have been compared with the predicted differences introduced by assuming that the source abundances resemble either solar system, pure r-, or pure s-process material. These comparisons allow us to determine how the uncertainties in the above mentioned parameters affect the abundances of the cosmic ray nuclei. We conclude that the uncertainties in nuclear cross sections presently prevent us from drawing any but the broadest conclusions from the measured abundances. |
