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BackgroundThe targeted acquisition of the radioactive element content or radioactivity in a radioactivity is an important task in geological exploration and radioactive pollution investigation. During the process of targeted gamma radiation sampling, gamma rays from non-target areas significantly interfere with the measurement results.PurposeThis study aims to design a dual-energy targeted gamma radiation sampling probe that uses a cerium bromide scintillation detector on the basis of the difference in the linear attenuation coefficients of the high- and low-energy gamma rays from the same radioactive decay series in the lead shielding layer of the detector.MethodsFirstly, Monte Carlo (MC) numerical simulations were employed to determine the optimal lead shielding layer thickness for the dual-energy targeted gamma radiation sampling probe detecting targets of the 0.609 MeV and 1.764 MeV gamma rays emitted by 214Bi. Then, the directional proportionality coefficients were calculated and applied to obtaining 0.609 MeV gamma ray counts of dual energy γ radiation probe within lead shielded angle. Finally, MC numerical simulations with four types of interfering radiation sources and physical experiments with two radium sources were conducted to validate the results that calculated using the directional proportionality coefficients.ResultsThe simulation result of optimal lead shielding layer thickness for the dual-energy targeted gamma radiation sampling probe is 6 mm, and the calculated directional proportionality coefficients of a and A are 0.268 and 0.451, respectively. Validation results show that the relative error between the counts for the 0.609 MeV gamma rays within the shielded angle and the net peak area counts measured with the dual-energy targeted gamma radiation sampling probe for two radium sources is within ±2.52% with average relative error of 0.63%. The relative errors between the measured uranium content and recommended values in the tested models are all less than 5%.ConclusionsThe dual-energy targeted gamma radiation sampling results for a radioactive mixed standard model and three radioactive models indicated that the designed dual-energy targeted gamma radiation sampling probe is capable of targeted gamma radiation sampling.

The release of pollutants from lead-zinc mining areas poses a significant threat to the environment, making pollution tracing crucial for environmental protection. However, the complexity of carbonate mining areas makes tracing these pollutants challenging. This study used δ34SSO4 and δ18OSO4 isotopes combined with the Stable Isotope Mixing Models in R (SIMMR) to assess anthropogenic sulfate sources in the Daliangzi mining area. The river water types were mainly Ca2+-Mg2+-HCO3−, and SO42−, which are significantly influenced by dolomite dissolution. The δ34SSO4 values ranged from 6.47‰ to 17.96‰ and the δ18OSO4 values ranged from −5.66‰ to 13.98‰. The SIMMR results showed that evaporite dissolution in tributaries, driven by gypsum, contributed 31% of sulfate, while sulfide oxidation, sewage, and atmospheric deposition contributed 19%, 18%, and 24%, respectively. The tailings pond near Xincha Creek has a higher sulfate release potential than the processing plant near Cha Creek. In the mainstream, sulfide oxidation contributed 25%, primarily from mine drainage. Anthropogenic sources, including sulfide oxidation, fertilizers, and sewage, made up about 50% of the total sulfate, with sulfide oxidation accounting for half of this input. The strong correlation between the Zn and SO42− concentrations (R2 = 0.82) and between the Zn and the contribution from the sulfide oxidation (R2 = 0.67) indicates their co-release during sulfide oxidation, making SO42− a proxy for tracing Zn sources. This study highlights the utility of δ34SSO4 and δ18OSO4 with SIMMR in tracing anthropogenic inputs and underscores the significant impact of mining on river systems and the sulfur cycle. [ABSTRACT FROM AUTHOR]

BackgroundAirborne gamma spectrometer is a method to measure ground gamma nuclide activity (specific activity) by installing gamma spectrometer on aircraft. The accuracy of results is affected by flight altitude and terrain fluctuation. At present, altitude correction has been applied to the quantitative analysis of airborne gamma spectrometer, but the correction effect of altitude correction on areas with large terrain fluctuation is not desirable.PurposeThis study aims to propose a 3D terrain correction method based on discrete integral.MethodsFirst of all, the basic characteristics of digital elevation model (DEM) and radiation field distribution were analyzed. Then, the effective detection area of airborne gamma spectrometer was divided into micro grid surface elements, and the contribution of micro elements to the counting rate of full energy peak of the airborne gamma spectrum was calculated. The terrain correction coefficient by discrete integral was realized by the terrain correction of airborne gamma spectrum measurement results, and the accuracy of airborne gamma spectrum measurement results was simultaneously improved. Finally, verification of this method was performed on the measured airborne gamma-ray spectrum data processing.ResultsVerification results show that the influence of terrain on gamma spectrum data is corrected effectively by the proposed method.ConclusionsThe 3D terrain correction method based on discrete integral can improve the consistency between airborne gamma spectrum measurement results and ground measurement results, and has the advantages of fast mesh division, altitude and terrain correction simultaneous.

BackgroundIn the long-term uninterrupted work of the real-time on-line monitoring system of water radioactivity, the spectrum drift, line broadening and shift of peak position are caused by the temperature change of the detector and various electronic components and the aging of components, which leads to the difficulty of spectral line analysis and the error of analytical results.PurposeThis study aims to develop a calibration device for real-time on-line monitoring system of water radioactivity based on cerium bromide detector.MethodsThe device was designed to consists of 137Cs standard source (exemption source), lead block, lead chamber with calibration hole and linear motor. The optimum opening radius of the calibration hole and the optimum thickness of the lead block were obtained by Monte Carlo simulation. The standard 137Cs source was used as the standard reference peak, and the calibration of peak position and peak area, the peak position drift and peak area of 137Cs full-energy peak was analyzed by software with real-time gain calculation and parameters adjustment. Finally, the device was applied to the field application verification.Results & ConclusionsResults of Monte Carlo simulation indicate that the optimum radius of the calibration hole is 2.2 cm and the optimum thickness of the lead block is 5 cm. The verification results shows that the device can limit the change of peak position and peak area to ±1% and ±5%, respectively.

The key to construct the hot-cell is to calculate the buildup factors of radiation-protection glasses. However, there are few reports about the calculation of the buildup factor of radiation-protection glasses. In this article, G-P approximation method coefficients of 5 radiation-protection glasses are calculated according to the chemical composition of radiation-protection glasses and data from ANSI/ANSI-6.4.3. Based on the computed results, buildup factors of these 5 glasses are studied, interpolated and compared with exposure buildup factors calculated by the equivalent thickness of lead for the energy of gamma-ray emitted by nuclides, such as 60Co. The results show that the fitting functions of exposure buildup factors and penetration depth have a high relevancy R2 for a specific energy, the method of equivalent thickness is only appropriate for thin glasses and special attention must be paid to the glass thickness and gamma-ray energy. The results can be used as reference for the construction and shielding performance assessment of the viewing window of the hot-cell.

To analyze samples without using standard, the energy dispersive X-ray fluorescence analysis (EDXRFA) of unknown samples was studied. The ratio R of coherent and incoherent scattering peaks of Kα in the original spectrum of target Rh was got through the measurement of Ti, Fe, Ni, Cu, Zn, Sr, Sn, Pb single element standard samples, then the relationship between R and the effective atomic number of the corresponding single element standard samples was established, and the fitting curve of Zeff-R was obtained. When it comes to solve the unknown samples, measure the unknown samples and get the R, then the effective atomic number of the unknown samples was obtained by substituting the R of unknown samples into the Zeff-R fitting curve, and then the atomic number could be used in the fundamental parameters method iteration to calculate its mass attenuation coefficient. The Ti, Fe, Ni, Cu, Zn, Sr, Sn, Pb single element standard samples were again used to calibrate the instrument and obtain Gi parameter which was applied in the fundamental parameters method iteration of the corresponding element when it comes to solve the unknown samples. In order to verify the reliability of the algorithm, the 15 national soil standard samples were analyzed through the algorithm of this article. The results showed that the calculated content of Ti, Fe, Ni, Cu, Zn were close to the standard content, and some low content element’s content errors were a little larger because of the scattering background and other factors. The results showed that this algorithm could be used in the situ energy dispersive X-ray fluorescence analysis.

BackgroundWith the vigorous development of the nuclear industry and the widespread application of nuclear technology, the radioactivity of inland water has become one of the key objects of radiation environmental monitoring. CeBr3 scintillation detector is one of candidates for water on-line radioactivity measurement system, but its detection efficiency is not high enough.PurposeThis study aims to improve the detection efficiency of the water on-line radioactivity measurement system by optimization of array CeBr3 detector layout, and reduce the detection limit.MethodsFirstly, calculate the optimal number of detectors in the system according to the minimum detectable activity concentration formula was calculated. Then, the Monte Carlo method was used to simulate the number and arrangement of ⌀45 mm×50 mm CeBr3 array detectors to obtain optimized arrangement of detectors. Finally, the water on-line radioactivity measurement system with optimized layout of array CeBr3 detectors was applied to continuous monitoring of the water bodIES of a river basin in Sichuan province.ResultsThe simulation results show that the three CeBr3 detectors placed in triangular arrangement and close to each other achieve a minimum detectable activity concentration of 0.1 Bq·L-1 for 137Cs radioactive source, meeting the design standard of system detection limit.ConclusionsThe monitoring results show that the system can effectively monitor the variations of radioactivity concentration of total α/β and 238U, 232Th and 40K in the water.

In energy dispersive X‐ray fluorescence analysis (EDXRF), many baseline estimation algorithms have been proposed for the accurate characteristic peak area. However, the true value of the characteristic peak area of measured spectrum is unknown and cannot be used to evaluate the accuracy of the baseline estimation algorithms. In this article, an assessment method was proposed based on Monte Carlo simulation, which can obtain the characteristic peak area, and evaluate the accuracy of the baseline estimation algorithms directly. Meanwhile, the accuracy and practicality of four baseline estimation algorithms were evaluated by the assessment method, which include statistics‐sensitive nonlinear iterative peak‐clipping (SINP), fast Fourier transform (FFT), adaptive iteratively reweighted penalized least squares (AirPLS), and automated iterative moving averaging (AIMA). Comparing the relative error of the characteristic peak area, AirPLS gave the best performance for baseline estimation in EDXRF. [ABSTRACT FROM AUTHOR]

An improved shift‐invariant wavelet (S‐I WT) de‐noising algorithm based on LLS operator is proposed for high‐resolution energy dispersive X‐ray fluorescence. Sym8 is chosen as the wavelet basis function and performed noise reduction on the analog signal. Comparison of the de‐noising effect of S‐I WT, improved WT and LLS S‐I WT (where LLS is the log square root operator) method are quantitatively evaluated by using evaluation criteria signal‐to‐noise‐ratio (SNR), root mean square error and Pearson correlation coefficient. Meanwhile, a new evaluation criterion of de‐noising effect, called peak area relative difference, is also proposed to evaluate the counting deviation. The results show that the LLS‐SI WT is simple and reliable, can effectively reduce pseudo‐Gibbs artificial signals and statistical fluctuation. Besides, this method simplifies the calculation, reduces the running time and improves the running efficiency. The LLS‐SI WT is also applied to reduce the noise after adding strong noise to the signal, the SNR has been improved from 14.0040 to 14.7552, and most of the characteristic peak information retains to the greatest extent. [ABSTRACT FROM AUTHOR]