• Collimated LaBr3 detector response function in radioactivity analysis of nuclear waste drums

    分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》

    摘要: The properties of a Lanthanum bromide (LaBr3) detector and its response functions were investigated via experiments and simulations in this paper. The LaBr3 detector had good relative energy resolution and higher efficiency than a high-purity germanium detector. Monte Carlo and other numerical methods were used to calculate the efficiencies of a LaBr3 detector with a square collimation window. A model of the numerical method was established based on a pure geometric model that was consistent with the experimental situation. The results showed that the detector response functions calculated by these methods were in great agreement with experimental results.

  • A novel method for gamma spectrum analysis of low-level and intermediate-level radioactive waste

    分类: 核科学技术 >> 辐射防护技术 提交时间: 2023-06-06

    摘要: The uncertainty of nuclide libraries in the analysis of the gamma spectra of low- and intermediate-level radioactive waste (LILW) using existing methods produces unstable results. To address this problem, a novel spectral analysis method is proposed in this study. In this method, overlapping peaks are located using a continuous wavelet transform. An improved quadratic convolution method is proposed to calculate the widths of the peaks and establish a fourth-order filter model to estimate the Compton edge baseline with the overlapping peaks. Combined with the adaptive sensitive nonlinear iterative peak, this method can effectively subtracts the background. Finally, a function describing the peak shape as a filter is used to deconvolve the energy spectrum to achieve accurate qualitative and quantitative analyses of the nuclide without the aid of a nuclide library. Gamma spectrum acquisition experiments for standard point sources of Cs-137 and Eu-152, a segmented gamma scanning experiment for a 200 L standard drum, and a Monte Carlo simulation experiment for triple overlapping peaks using the closest energy of three typical LILW nuclides (Sb-125, Sb-124, and Cs-134) are conducted. The results of the experiments indicate that (1) the novel method and gamma vision (GV) with an accurate nuclide library have the same spectral analysis capability, and the peak area calculation error is less than 4%; (2) compared with the GV, the analysis results of the novel method are more stable; (3) the novel method can be applied to the activity measurement of LILW, and the error of the activity reconstruction at the equivalent radius is 2.4%; and (4) The proposed novel method can quantitatively analyze all nuclides in LILW without a nuclide library. This novel method can improve the accuracy and precision of LILW measurements, provide key technical support for the reasonable disposal of LILW, and ensure the safety of humans and the environment.