BackgroundIn recent years, the monitoring of Marine radionuclides has faced some challenges, such as the accuracy and reliability of monitoring data, and the cost and efficiency of monitoring methods.PurposeThis study aims to improve the analysis efficiency and accuracy of 134Cs nuclides in seawater.MethodsThe Ammonium Molybdophosphate (AMP) was applied to the adsorbent of 134Cs nuclides in seawater, and a novel synthesis method was developed to enhance the enrichment efficiency of cesium isotopes in seawater. Then, the activity of 134Cs in seawater was analyzed by three methods using the TrueCoinc program to carry out the coincidence summing corrections of the activity results. The second was the sum-peak absolute activity measurement method without the standard source calibration detector, relying on the full-energy peak count rate, the peak count rate and the total net count rate. The third was the sum-peak distance fitting method, which serves as an optimized approach derived from the sum-peak absolute activity method. Finally, experimental measurement was performed to compare and discuss the applicability, advantages, and limitations of these three methods.ResultsComparison results show that the traditional efficiency curve method requires cascade coincidence summing correction for 134Cs nuclides while the TrueCoinc program is used to calculate the correction factors of 7 energy peaks of 134Cs nuclides by combining the parameters of full-energy peak efficiency and total-peak-ratio curve, etc. The calculated results are in good agreement with the true values. According to the peak absolute activity calculation method, the full-energy peak count rate, the peak count rate and the total net count rate need to be calculated. For 134Cs nuclides, only 604 keV and 795 keV with high emission probability are used. Although the 134Cs absolute activity calculation formula is approximated and simplified, the deviation between the verification result and the reference activity is within 6%.ConclusionsThe efficiency curve method is suitable for samples with reference source available in the laboratory, and the sum-peak absolute activity calculation method is suitable for samples with no reference source and less interference nuclides. The improved method does not need the total net counting rate parameter, so the sum-peak absolute activity method has better universality.
ZHU et al. (Sun,) studied this question.