BACKSCATTERING COEFFICIENTS FOR LOW ENERGY ELECTRONS

Abstract

We present new experimental results of the backscattering coefficient (η) for C, Al, Cu, Ag and Au targets bombarded with low energy electrons (0.6-6 keV) at normal angles of incidence. The present data show a clear monotonic increase in the backscattering coefficient with increasing target atomic number for electrons of primary energy less than 1 keV in contrast with previously published data. A fundamental difference between this study and other reported measurements is that the present data set is collected from in situ cleaned surfaces under ultra high vacuum conditions (10 -10 mbar), while the previously reported studies were carried out under conventional vacuum (10 -5 mbar). Data of η values from mechanically cleaned and in situ Ar ion bombarded samples are compared with other published η data.