Surface effect in measurement of bombarding spectra

The surface effect in the spectrum measurement of radioactive sources bombarding targets was studied. The existence of surface effect was validated by comparative experiments of Mg bombarded-targets using mixed electron and X-ray source and X-ray source. And the effect not only has a relationship to the electrons but also shows some characteristics of the target surface. It is inferred that there is a stopping layer on the Mg bombarded-target surface through the experiment about the variation of spectra with target storage time, and the stopping layer can stop new-state hydrogen atoms diffusing from the target surface. The spectra of radioactive sources bombarding Re target and burnished and unburnished Mg targets indicate that, the stopping layer may be a new-state hydrogen atom enrichmen