Efficiency calibration method for HPGe detector in segmented gamma scanning based on weighted geometric factor

The segmented gamma-scanning (SGS) measurement is a non-destructive analysis technology. It is an important method of qualitative and quantitative analyse for nuclear waste drums. However, the HPGe detectors detection efficiency is related with the location of the radionuclide in the actual measuring process, so it is necessary to do efficiency calibration for different locations. This paper presents the study based on SGS measurement method. The waste drum was filled with uniform polyethylene samples. The radionuclides were approximated as point sources. Seven points were selected in each of the three uniform segments of the drum for efficiency calibration. Shell-source method and geometrical factor method were used to calculate the weighted detection efficiency for calibration of each point. The results show that this method can estimate the nuclide activity at different positions in the drum quickly and accurately with acceptable errors.