Application of sourceless efficiency method in measuring ²²⁷Ac in rare earth products

The paper studies the determination method of the specific activity of ²²⁷Ac in rare earth products. By the application of sourceless efficiency method on HpGe-γ ray spectrometer, we have measured the specific activity of ²²⁷Ac in rare earth products of different processes through appropriate analysis of the spectrum. The results show that: firstly, lanthanan products, such as lanthana, is generally accompanied by ²²⁷Ac, which contributes greatly to the contamination of lanthana. Secondly, the existence of ²¹¹Bi, daughter of ²²⁷Ac, could be affirmed when the net counts of the peak at the energy of 351 keV presents high, while the peak at energy of 609 keV low in the spectrum! Thirdly, the influence of ²³⁴Pa could be ignored in the rapid analysis of ²²⁷Ac. (authors)