Published online by Cambridge University Press: 06 March 2019
Measurements have been made on the FeLII/LIII intensity ratio on oxide free iron surface produced by evaporating a 50 Å Ti film on iron. These results show that the reported increase in the FeLII/LIII ratio with decreasing accelerating voltages is due largely to surface oxide and not self absorption. Also, for the vacuum presently used by soft x-ray spectroscopists the oxide surface on metals contribute strongly to the soft x-ray spectra of the bulk material for accelerating voltages below 4 kV.