Electron Transport Properties for Soft Electron Sources Incident on Conducting and Insulating Materials

In this paper, we have reported on two recent analyses carried out using the code SXRP to treat external electron sources. The first analysis concerned backscatter from Al and Au and was undertaken to critically test the scattering and energy loss characteristics in our material models. We feel the test was successful based on the agreement obtained with published primary backscatter yield data between 0.5 and 20 keV. Since photoemission characteristics are less sensitive to transport parameters than those for backscatter, these tested models, as used by code SXRP, should be especially valid for the problem of photoemission. This has already been indicated by the agreement obtained with the available published photoemission data. The second analysis concerned current and dose profiles in Teflon and was undertaken to test one aspect of a charging calculation by Beers, et al. concerned with the larger problem of spacecraft charging. The points of this analysis were to determine the applicability of code SXRP to specifying internal transport characteristics, but more specifically to see how important straggling is to the above profiles since their falloff behavior deep in the material is important to the applied charging model. Beers, et al. had used the transport code POEM to obtain their current and dose profiles which does not permit an electron to go beyond one CSDA range.