Contribution of backscattered electrons to the total electron yield produced in collisions of 8—28 keV electrons with tungsten

摘要

It is shown experimentally that under energetic electron bombardment the backscattered electrons from solid targets contribute significantly (～80%) to the observed total electron yield, even for targets of high backscattering coefficients. It is further found that for tungsten (Z = 74) with a backscattering coefficient of about 0.50, about 20% of the total electron yield is contributed by the total secondary electrons for impact energies in the range of 8-28 keV. The yield of true backscattered electrons at normal incidence (η_0), total secondary electrons (δ) and the total electron yield (δ_(tot)) produced in collisions of 8-28 keV electrons with W have been measured and compared with predictions of available theories. The present results indicate that the constant-loss of primary electrons in the target plays a significant role in producing the secondary electrons and that it yields a better fit to the experiment compared to the power-law.