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Method for rapid warning and activity concentration estimates in online waterγ-spectrometry systems

Nuclear Science and Techniques 2024年第3期35卷 1-12页

作者： Meng Wang Yi Gu Mao-Lin Xiong liang-quan ge Qing-Xian Zhang Guo-Qiang Zeng Heng Lu Sheng-liang Guo College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China Applied Nuclear Technology in geosciences Key Laboratory of Sichuan Province (Chengdu University of Technology)Chengdu 610059China Chengdu New Ray Technology Co.Ltd Chengdu 610052China

Onlineγ-spectrometry systems for inland waters,most of which extract samples in situ and in real time,are able to produce reliable activity concentration measurements for waterborne radionuclides only when they are distributed relatively uniformly and enter into a steady-state diffusion regime in the measurement *** protect residents’health and ensure the safety of the living environment,better timeliness is required for this measurement *** address this issue,this study established a mathematical model of the online waterγ-spectrometry system so that rapid warning and activity estimates can be obtained for water under non-steady-state(NSS)*** addition,the detection efficiency of the detector for radionuclides during the NSS diffusion process was determined by applying the computational fluid dynamics technique in conjunction with Monte Carlo *** this basis,a method was developed that allowed the online waterγ-spectrometry system to provide rapid warning and activity concentration estimates for radionuclides in *** analysis of the NSS-mode measurements of^(40)K radioactive solutions with different activity concentrations determined the optimum warning threshold and measurement time for producing accurate activity concentration estimates for *** experimental results show that the proposed NSS measurement method is able to give warning and yield accurate activity concentration estimates for radionuclides 55.42 and 69.42 min after the entry of a 10 Bq/L^(40)K radioactive solution into the measurement chamber,*** times are much shorter than the 90 min required by the conventional measurement ***,the NSS measurement method allows the measurement system to give rapid(within approximately 15 min)warning when the activity concentrations of some radionuclides reach their respective limits stipulated in the Guidelines for Drinking-water Quality of the WHO,suggesting that this method con

关键词： Water radioactivity monitoring Dynamic detection efficiency Rapid warning Activity estimation

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Determination of gross α and β activities in Zouma River based on online HPge gamma measurement system

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Nuclear Science and Techniques 2020年第12期31卷 65-76页

作者： Xian Guan liang-quan ge Guo-Qiang Zeng Xiao-Qin Deng Li-Peng Xu Sheng-liang Guo Key Laboratory of Applied Nuclear Techniques in geosciences of Sichuan Province Chengdu University of TechnologyChengdu 610059China Sichuan Management&Monitoring Center Station of Radioactive Environment Chengdu 610031China Chengdu New Nuclear Tyco Technology Co. LtdChengdu 610052China

This paper describes a low-cost and fast method to evaluate gross α and β^(-) radioactivities in natural water based on an online high-purity germanium detector gamma measurement *** major gamma activities in natural water are provided by natural and artificial radionuclides such as ^(40) K,^(137)Cs,and radionuclides belonging to ^(238)U and ^(232)Th *** main a emitters related to gamma emissions in natural water are ^(224)Ra(240.98 keV)and ^(226)Ra(186.21 keV),and the β^(-) emitters are ^(40) K(1460.85 keV),^(214)Bi(609.31 keV),^(208)Tl(583.19 keV),and ^(214)Pb(351.93 keV).The formula for gross α and β^(-) activity concentration is based on these radionuclides,and the short half-life decay products are considered in the *** detection efficiency of the device across energy region(0–3 MeV)is obtained through Monte Carlo simulation,and a calibration experiment is conducted to verify the simulation *** radioactivity is measured continuously for 114 d in Pixian County and Dongfeng Canal located in the Zouma River,Chengdu,Sichuan Province,China.A comparison of the calculation results and monitoring data from the Sichuan Management and Monitoring Center Station of Radioactive Environment indicates that the percentage and absolute error of a activity concentration is lower than 53%and 0.02 Bq/L,respectively,and that of β-activity concentration is lower than 33.2%and 0.016 Bq/L,*** method can rapidly determine gross α and β^(-) activity concentrations in natural water online.

关键词： Grossαandβ^(-)activity HPge gamma spectrometer Online radioactivity level measurement for natural water Natural radioactivity Water sources of Chengdu

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Evaluation of terrestrial radiation in the Chengdu Plain using 1/250,000-scale geochemical prospecting data

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Nuclear Science and Techniques 2017年第10期28卷 31-36页

作者： Qing-Xian Zhang Jian-Kun Zhao Yi Gu liang-quan ge Yuan-Qing Huang Sichuan-Provincial Key Laboratory of Nuclear Technologyin geosciences Chengdu University of TechnologyChengdu 610059China Sichuan Nuclear geology Institute Chengdu 610061China

Based on the geochemical prospecting data, we have calculated the gamma absorbed dose rates in air 1 m above the ground surface in the Chengdu Plain, analyzed the relationship between the geological conditions and the distribution of the natural radionuclides, and preliminarily studied the influence of the geological conditions on the terrestrial radiation level in the Chengdu Plain. The result shows that the terrestrial radiation level in the Chengdu Plain is slightly lower than the average values of China and varies greatly according to the complex geological conditions.

关键词：成都平原地面辐射地球化学找矿评价天然放射性核素地质条件辐射水平普查数据

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quantitative energy-dispersive X-ray fluorescence analysis for unknown samples using full-spectrum least-squares regression

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Nuclear Science and Techniques 2019年第3期30卷 149-159页

作者： Yong-Li Liu Qing-Xian Zhang Jian Zhang Hai-Tao Bai liang-quan ge The College of Applied Nuclear Technology and Automation Engineering Chengdu University of Technology

The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid *** on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.

关键词： Energy-dispersive X-ray fluorescence analysis Full-spectrum least-squares method Effective atomic number Mass attenuation coefficient Fundamental parameter method

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Implementation of a cusp-like for real-time digital pulse shaper in nuclear spectrometry

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Nuclear Science and Techniques 2017年第7期28卷 79-84页

作者： Jun Liu Jian Yang Guo-Qiang Zeng Kai-Qi Zhang Shi-Long Wei liang-quan ge Chengdu University of Technology Chengdu 610059 China

Pulse shaping,which improves signal-to-noise ratio excellently,has been extensively used in nuclear signal *** paper presents a cusp-like pulse-shaping technique developed through the recursive difference equation in time *** can be implemented in field programmable gate array hardware *** flat-topped cusp-like shaper is developed to optimize the time constant of pulse shaping and reduce the influence of ballistic *** methods of both baseline restoration and pile-up rejection are *** ^(137)Cs energy spectra measured with the digital cusp-like shaper are 6.6% energy resolution,while those by traditional analog pulse shaper are 7.2% energy resolution,under the same *** technique offers flexibility,too,in adjusting the pulse shaper parameters.

关键词：脉冲整形器现场可编程门阵列能量分辨率尖点实时谱仪递归差分方程整形技术

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Analog rise-time discriminator for CdZnTe detector

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Nuclear Science and Techniques 2017年第4期28卷 59-65页

作者： Chuan-Hao Hu Guo-Qiang Zeng liang-quan ge Shi-Long Wei Jian Yang Qiang Li Hong-Zhi Li Chengdu University of Technology Chengdu 610059 China National Ocean Technology Center Tianjin 300112 China

Due to variable time for charge collection,energy resolution of nuclear detectors declines,especially compound semiconductor detectors like cadmium zinc telluride(CdZnTe) *** solve this problem,an analog rise-time discriminator based on charge comparison principle is *** reference charge signal after attenuation is compared with the deconvoluted and delayed current *** is found that the amplitude of delayed current signal is higher than that of the reference charge signal when rise time of the input signal is shorter than the discrimination time,thus generating gating signal and triggering DMCA(digital multi-channel analyzer) to receive the total integral charge *** rise time of the input signal is longer than discrimination time,DMCA remains inactivated and the corresponding total integral charge signal is *** results show that combination of the designed rise-time discriminator and DMCA can reduce hole tailing of CdZnTe detector *** resolution of the system is 0.98%@662 keV,and it is still excellent under high counting rates.

关键词： Analog rise-time discriminator CdZnTe detector Charge comparison principle

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Fast nuclide identification based on a sequential Bayesian method

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Nuclear Science and Techniques 2021年第12期32卷 116-127页

作者： Xiao-Zhe Li Qing-Xian Zhang He-Yi Tan Zhi-Qiang Cheng liang-quan ge Guo-Qiang Zeng Wan-Chang Lai Chengdu University of Technology The College of Nuclear Technology and Automation EngineeringChengdu 610059China

The rapid identification of radioactive substances in public areas is ***,traditional nuclide identification methods only consider information regarding the full energy peaks of the gamma-ray spectrum and require long recording times,which lead to long response *** this paper,a novel identification method using the event mode sequence(EMS)information of target radionuclides is *** EMS of a target radionuclide and natural background radiation were established as two different probabilistic models and a decision function based on Bayesian inference and sequential testing was *** proposed detection scheme individually processes each *** a photon is detected and accepted,the corresponding posterior probability distribution parameters are estimated using Bayesian inference and the decision function is ***,value of the decision function is compared to preset detection thresholds to obtain a detection ***ments on different target radionuclides(137Cs and 60Co)were *** count rates of the regions of interest(ROI)in the backgrounds between[651,671],[1154,1186],and[1310,1350]keV were 2.35,5.14,and 0.57 CPS,*** experimental results demonstrate that the average detection time was 6.0 s for 60Co(with an activity of 80400 Bq)at a distance of 60 cm from the *** average detection time was 7 s for 137Cs(with an activity of 131000 Bq)at a distance of 90 cm from the *** results demonstrate that the proposed method can detect radioactive substances with low activity.

关键词： Natural radiation Nuclide identification Sequential testing Nuclear safety

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Verification of a self-developed CFD-based multi-physics coupled code MPC-LBE for LBE-cooled reactor

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Nuclear Science and Techniques 2021年第5期32卷 84-100页

作者： Zhi-Xing Gu Qing-Xian Zhang Yi Gu liang-quan ge Guo-Qiang Zeng Mu-Hao Zhang Bao-Jie Nie College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

To perform an integral simulation of a pool-type reactor using CFD code,a multi-physics coupled code MPC-LBE for an LBE-cooled reactor was proposed by integrating a point kinetics model and a fuel pin heat transfer model into self-developed CFD *** code verification,a code-to-code comparison was employed to validate the CFD ***,a typical BT transient benchmark on the LBE-cooled XADS reactor was selected for verification in terms of the integral or system *** on the verification results,it was demonstrated that the MPC-LBE coupled code can perform thermal-hydraulics or safety analyses for analysis for processes involved in LBE-cooled pool-type reactors.

关键词： LBE-cooled pool-type reactor Computational fluid dynamics Multi-physics coupling code Safety analysis code Verification

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Investigating the minimum detectable activity concentration and contributing factors in airborne gamma-ray spectrometry

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Nuclear Science and Techniques 2021年第10期32卷 30-38页

作者： Yi Gu Kun Sun liang-quan ge Yuan-Dong Li Qing-Xian Zhang Xuan Guan Wan-Chang Lai Zhong-Xiang Lin Xiao-Zhong Han The College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China Key Laboratory of Applied Nuclear Techniques in geosciences of Sichuan Province Chengdu University of TechnologyChengdu 610059China China Coal geology Group Co. LtdBeijing 100040China

In this study,the theory of minimum detectable activity concentration(MDAC)for airborne gamma-ray spectrometry(AGS)was derived,and the relationship between the MDAC and the intrinsic effi-ciency of a scintillation counter,volume,and energy res-olution of scintillation crystals,and flight altitude of an aircraft was *** verify this theory,experi-mental devices based on NaI and CeBr 3 scintillation counters were prepared,and the potassium,uranium,and thorium contents in calibration pads obtained via the stripping ratio method and theory were *** MDACs of AGS under different conditions were calculated and analyzed using the proposed theory and the Monte Carlo *** relative errors found via a comparison of the experimental and theoretical results were less than 4%.The theory of MDAC can guide the work of AGS in probing areas with low radioactivity.

关键词： Airborne gamma-ray spectrometry(AGS) Minimum detectable activity concentration(MDAC) Sensitivity

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Design study of charge-stripping scheme of heavy ion beams for HIAF-BRing

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Nuclear Science and Techniques 2024年第5期35卷 30-41页

作者： Jun-Jie Zhang Zhi-You Xu Jin-quan Zhang Wen-Wen ge liang-Ting Sun Huan-Yu Zhao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

Charge strippers play an essential role in heavy-ion accelerators by stripping the projectile ions to higher charge states to enhance the acceleration efficiency downstream of the *** the high-energy mode of the booster ring(BRing)of the high-intensity heavy-ion accelerator facility,the pre-accelerated ions from the iLinac will be stripped by a carbon foil to higher charge states and then injected into the *** key parameters of the stripper and stripped ions were calculated,and the influence of stripping on the beam quality was *** get high stripping efficiencies,the foil thicknesses and resultant charge state distributions for the typical ions were determined by the code *** equilibrium thickness was obtained for the U beam,while the stripper thicknesses for the Xe and Kr beams were determined based on a compromise between the stripped charge states and the stripping *** energy loss,energy straggling,and emittance growth due to stripping have a non-negligible impact on the transport of the stripped beams and the injection of the ***,these parameters were simulated by *** addition,the foil’s temperature evolution,which greatly affects the foil lifetime,was simulated by *** maximum temperature of the foil bombarded by the U and Xe beams with the nominal parameters will exceed the safe value in terms of the impact of evaporation on the foil’s *** the foil temperature constraint,the highest tolerable beam intensity and the injected ion number into the ring were derived for different beam *** results of this paper will present important reference data for the optimization design and commissioning of the beamline and injection to the BRing for the stripped ions.

关键词： High-intensity heavy-ion accelerator facility Charge stripper Energy spread Thermal analysis Emittance growth Injection turns

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