Background: In the non-destructive measurement

including the analysis of material composition of nuclear forensics

fission product analysis of nuclear terrorism event and large sample activation analysis

there is a big challenge for the detection efficiency calibration. Purpose: This paper analyzed the basic principle of the relative efficiency method of radiation samples with multi-nuclide

and established the relative efficiency fitting method for multi-nuclide. Methods: Through the peak information of the fission products from a special irradiated uranium sample

the efficiency fitting of dual-nuclide (parent-daughter nuclides) and three nuclides (no parent-daughter nuclides) was verified. Results: The study showed that the calibration factor of the self-calibration method with multi-nuclide was consistent with the factor of the parent-daughter nuclides’ decay in the error range of 2%. Conclusion: Results laid the foundation for the non-destructive analysis techniques of the radioactive samples with special shapes. Abstract