Abstract: Aiming at the problem of gamma-ray characteristic peak interference correction in gamma spectrometry during a CNNC Environmental monitoring labs comparison, this paper conducts measurement experiment of uranium, thorium, radium and potassium in soil. When calibrating the efficiency of the spectrometer with natural soil standard source, it is necessary to analyze whether the gamma-ray characteristic peaks are interfered by other rays, and correct the efficiency by modifying the Nuclide activity value when calculating efficiency. When analyzing the nuclide activity of the samples by Gamma-Vision software, the activity correction should be carried out if the nuclide activity calculated by different characteristic rays is quite different. The characteristic peaks (such as ²³⁵U 185.7 keV, ²³⁸U 92.6 keV) used in the calculation of nuclide activity are analyzed, the contribution of the interference peak to the measured energy spectrum (Overlapping Peak) activity is deducted. This method gives qualified ²³⁸U,²²⁶Ra,²³²Th,⁴⁰K and ¹³⁷Cs data in CNNC soil sample comparison.

Key words: gamma spectrometry, gamma-ray characteristic peak interference correct, Gamma-Vision software analysis method