high atomic number (high positive load of the atomic core)
produce more back scattered electrons than the ones that have a
low atomic number. The areas of the sample with a high atomic
number (here stained EPDM-domains) will thus look whiter
than the ones with a low atomic number. Thus, they give more
phase information as compared to secondary electrons. They
have higher energy from the secondary electrons and they
come from the bulk of the sample. The resolution reached by