The absolute emission yields of photon-induced electrons from Al

Fe

Cu

Ta and W foils have been measured by the improved Millikan’s method to detect the photoelectric current in the incident direction. The experimental results show that the yield of photoelectron is decreased with the increasing of the foil’s thickness and there are more radiation-induced electrons emitting from the higher Z materials. A model known as " contribution of range layer" has been suggested. The calculated yields based on the model agree with the experimental data with a relative error of 10% on the average.