[en] For the measurement of radon daughters using alpha spectrometers, it is important to know the difference of detection efficiencies between higher energy α particles and lower one. The detection efficiencies of the ORTEC eight-channel alpha spectrometer working station for higher energy α particle and lower one are measured by an ²⁴¹Am alpha standard source and a radon progeny standard source made by Canada Pylon Company, and the difference between the two was analyzed. The results show that the gross spectrum efficiencies of the two sources are equal within the deviations, and after the correction of the peak overlap the detection efficiency of α particle with higher energy is a little higher than that of the one with lower energy. So using radon progeny standard source is better than using ²⁴¹Am source, because using radon progeny standard source to calibrate a device is more suitable to the practical radon progeny measurement situation than using ²⁴¹Am. (authors)