目的 利用LabSOCS无源效率刻度软件模拟优化马林杯状源盒,探究HPGe探测器测量惰性气体的探测效率,为核电站惰性气体流出物的测量优化提供参考.方法 利用LabSOCS软件建立了马林杯模型,探究各惰性气体γ射线的探测效率随气体成分、气体密度、马林杯尺寸参数、马林杯体积、测量源盒形状的变化关系.结果 气体成分对马林杯中惰性气体的探测效率几乎没有影响,低能γ射线的探测效率受气体密度影响较大,选择合适的马林杯高度和半径能够使HPGe探测器获得更好的测量结果.对于BE5030HPGe探测器,不同体积的马林杯探测效率最高值均位于半径/高度=0.7位置处,并给出不同体积的马林杯高度和半径的最优值.结论 选择合适的马林杯尺寸能够提高核电站流出物中惰性气体的探测效率.

Objective::To explore the concentration level of radionuclide in mushrooms in northeast China, and to analyze the risk of the effective dose of edible mushrooms to the human body.Methods::A total of 68 samples of 18 species of mushrooms from three regions in northeast China and Beijing as control were collected from 2017 to 2020. The activity of radionuclide in mushrooms was measured by gamma-spectrometry, and the activity was analyzed by statistical analysis. The relationship between 137Cs and 40K content in mushrooms was explored. Results::238U was undetected in all samples. The activity concentration of 226Ra, 232Th, 40K, 137Cs were in range of 1-34.3, 2.26-32.3, 208-2,388 and 0.6-130.3 Bq/kg, respectively. The 137Cs and 40K concentrations in mushrooms were not correlated. The risk analysis of radioactivity in the collected mushrooms showed that the highest effective dose of the 18 kinds of mushrooms was 0.042 mSv. Conclusion::The radionuclide content of mushrooms in northeast China is within the normal range. The mushrooms will not cause risk to human health.

To study the content of radionuclides in coal and to assess its associated radiological impact on the environment for potential radiological risk assessment, a total of 40 coal samples were collected from various mining areas in eight provinces of China. The specific activities of Ra-226, Th-232, K-40, Pb-210, and U-238 were measured in all samples using an HPGe gamma-ray spectrometer, and results were compared with available data from other similar studies. The results reveal that the radium equivalent activity was 74.20 Bq kg(-1), external hazard index was 0.20, internal hazard index was 0.27, representative gamma index was 0.52, and indoor and outdoor annual effective dose rates were 0.16 nSv y(-1) and 0.04 nSv y(-1), respectively. Absorbed gamma dose rate in air was 32.87 nGy h(-1). In general, these values are lower than the respective threshold limits recommended by UNSCEAR, and the radiation risk to the public is extremely small.

Objective:To improve the radionuclide measurement technology by γ-spectrometry throuth a review of the intercomparisons between China and Japan results over the past 20 years.Methods:Before the beginning of each intercomparison, one of participating laboratories was agreed to be responsible for preparing the samples for the intercomparison. By intercomparison of the measurement results arnong the laboratories some potential problems during the sample pre-trement or analysis were found and solved.Results:The intercomparisons had been carried out for 11 times over the past 20 years. Totally 290 measured and analyzed results had been obtained from 20 samples of six categories. The proportion 95.5% of measurement results were in agreement with each other within the deviation range.Conclusions:The measuring and analytical capability of the laboratories involved were tested. The intercomparisons also provide long-term quality assurance measures for the radionuclide measurement and analysis in each laboratory.

This study reports the performances of efficiency calibrations for high-purity-germanium gamma-ray spectrometry using the source-, Laboratory Sourceless Object Calibration Software (LabSOCS)- and ANGLE-based methods in an inter-comparison exercise. Although the results of LabSOCS and ANGLE for (241) Am emitting low-energy gamma rays were not very satisfactory, all of the three efficiency calibration methods passed acceptance criteria. The results confirmed the reliability of the calculation codes ANGLE and LabSOCS as alternative efficiency calibration methods in high-purity-germanium gamma spectrometry. This study is likely to promote the further application of the ANGLE and LabSOCS calculation codes in radioactivity measurements.

Objective Obtain the background data of environmental gamma radiation dose rate in the surrounding areas before the operation of Haiyang Nuclear Power Plant, and provide basis for evaluating the impact on the surrounding environment after the operation of the nuclear power plant. Methods The environmental gamma radiation dose rate was measured by vehicle radiation monitoring system (GR460) within 30 km of Haiyang Nuclear Power Pland and the resultant radiation dose exposure to local residents was also estimated.Results The air absorbed dose rate ranges from 39.6 to 109 nGy/h, and the average is 72.2 nGy/h. There is a significant difference between the mean values of gamma radiated air absorbed dose rates in the regions of 0～5 km, 5～10 km, 10～20 km and 20～30 km of nuclear power plant. The per capita annual effective dose of residents caused by gamma radiation dose rate in outdoor environment is 84.8 μSv. Conclusion The environmental gamma radiation dose rate in the surrounding areas of Haiyang Nuclear Power Plant and the resultant radiation dose exposure to the local residents was were within the normal background level in China.

Eight years since the Fukushima Daiichi nuclear power plant accident (March 11,2011),social impact and health risk remain as major and continuous public concerns.This study analyzes the situation of Fukushima nuclear accident after March 11,2011 and the reports published by international authority organizations.This work also assesses the impact of Fukushima nuclear accident on the environment and human health after eight years and summarizes its lessons for China.

Objective To standardize the operation and data processing in radiological health institutions in China, in order to promote the assessment of γ-spectrometry, improve the measurement and analysis capabilities of each laboratory, and accordingly improve accuracy of environment sample measuring. Methods By collecting the values of 232 Th, 40 K and 137 Cs contents in soil samples from 2015 to 2017, the assessment results of γ-spectrometry laboratores were summarized and analyzed. Results The technical institutions from 25 provinces were involved in the assessment until 2017, including disease control and prevention centers, entry-exit inspection and quarantine agencies, research institutes, universities and companies. The number of participants was increased from 40 to 48, and the qualified rate exceeded 90％, and the excellent rate was no less than 11％ each year. The percentage of relative deviation less than 10％ between the measuring result of 232 Th, 40 K and 137 Cs contents and the reference value was larger than 80％ in 2017. The accuracy became better. However, the number of institutions with U and Z score less than 1 was increased from 11 to 25, suggesting that the precision of measuring result has also been greatly improved. Conclusions Radiological health institutions in China have good measurement and analysis capabilities with regard to γ-spectrometry, which can meet the needs of environmental sample measurement and in-food radionuclide risk monitoring in an emergency of nuclear and radiation. But a few institutions′ measuring results were largely different from the reference values, as a consequence, it is important to strengthen their ability of measurement and analysis.

目的 为了掌握卫生系统对食品中γ放射性核素检测能力现状,发现检测工作中的潜在问题,为今后各实验室改进和提高检测能力提供参考.方法 通过各实验室上报的高纯锗γ能谱仪的性能指标,掌握各实验室的γ放射性核素检测的硬件能力.通过组织检测能力考核,了解各实验室检测人员的技术能力.结果 各实验室γ能谱仪的相对探测效率分布在30％～ 66％,能量分辨率分布在1.60～2.28 keV,测量24 h 50～2 000 keV的积分本底分布在48～420 CPM,检测能力考核结果达到“合格”及“优秀”的占大多数.结论 当前我国卫生系统对食品中γ放射性核素检测能力普遍良好,但部分实验室的仪器性能或人员技术仍有待提高.

目的 建立核辐射事件发生后应急情况下环境样品中放射性核素的γ能谱快速分析方法.方法 通过调研国内外核辐射应急标准,并结合我国实际,制定了在核辐射事件发生后应急情况下,对环境样品样品的采集、预处理、γ能谱测量、出具结果报告的流程.结果 采用2L马林杯样品盒,在测量10 min的情况下,131I和137 Cs的最小可探测活度浓度在102 (Bq/kg)量级.结论 建立了一种测量核辐射应急情况下放射性核素的γ能谱快速分析方法,满足核应急情况下对OIL6中的要求.

Objective To validate the effect of the Laboratory Sourceless Calibration Software (LabSOCS) in the actual sample measurement,and to study the effect of sample self-absorption correction and cascade radiation coincidence correction.Methods Two standard samples from the analytics company were measured using the two gamma spectrometers at our laboratory.The result were calculated using the efficiency generated by LabSOCS.Calculated result of each nuclide were analyzed.Results were compared with the standard value provided in the certificate.Results The LabSOCS may solve the problem of sample self-absorption correction in gamma energy spectrum measurement and analysis.The maximum deviation between the values of 241Am and 109Cd analyzed by LabSOCS and the reference value was less than 4％ for the broad-energy high-purity germanium gamma-ray spectrometers.However,the coincidence additive correction caused by cascade radiation could not be solved directly.Conclusions The research shows that the LabSOCS can solve the problem of sample self-absorption correction by describing the composition and density of the samples accurately.However,when analyzing the nuclides with cascade radiation,the coincidence addition effects should be considered.The flexible simulation method of the LabSOCS can be used to increase the distance from the cascade nuclide sample to the detector and to complete the accurate measurement of the cascade nuclide.

Natural and fallout radioactivity were estimated in topsoil samples collected in eastern region of Shangrao Prefecture, China. The average activity concentrations of 238U, 226Ra, 232Th and 40K in the soil were nearly 2 times the world median value and Chinese average. The 137Cs activity concentration decreased compared with the previously reported value in the same region. The absorbed dose rate and annual effective dose rate estimated in the study area are found to be both higher than the world average values. 238U/226Ra and 232Th/226Ra activity ratios were also considered in this study.

Objective To study the variation in net count rates of natural radionuclides in background of gamma-ray spectrometer,so as to provide a scientific basis for reducing the effect of background fluctuations on sample measurement.Methods The unscheduled background spectrum obtained using two high-purity gamma-ray spectrometers during 2013-2017 were collected,and then the net count rates of 210pb,234Th,212Pb,214pb,208Tl,214Bi,228Ac and 40K were calculated and analyzed by aid of statistical method.Results There was a significant difference in the net count rates of 210Pb,234Th,212Pb,214Pb,208Tl,214Bi,228Ac and 40K in the background spectrum of gamma-ray spectrometer,and the net count rates of 214Pb,214Bi and 40K was significantly higher than those of 210Pb,234Th,212pb,208Tl and 228Ac.There were no significant differences in the net count rates of these eight natural radionuclides from 2013 to 2017,respectively (P ＞ O.05).However,the coefficients of variation in the net count rates for 214pb and 214Bi were both greater than 50％.Conclusions When the activity concentration of natural radionuclides is determined in a sample by gamma-ray spectrometer,it is critical to subtract the background spectrum obtained recently to ensure the accuracy of the measurement,especially for the low activity concentration of natural radionuclide to be measured.

96 aerosol samples were collected in north China and analyzed by gamma spectrometry. The activity concentrations of Pb-210 ranged from 97 to 27,955 μBq/m3, with average of 879, 3389 and 813 μBq/m3 in Beijing, Changbai and Hunchun, respectively. Annual effective dose for inhabitants due inhalation varied from 0.68 to 5.94 μSv. There was a positive correlation between Pb-210 and PM2.5 in Beijing. Seasonal variation of Pb-210 concentration was observed in Changbai and Hunchun. Analysis of their correlation with meteorological parameters could help to assess the effects of present pollutant emission and provide scientific support for prevention strategy.

Activity concentrations of 238U, 226Ra, 228Ra, 137Cs and 40K in 64 mushroom samples collected in China from Yunnan, Fujian and Heilongjiang Provinces, were measured. Gamma-ray emissions were determined by using high-purity germanium (HPGe) γ spectrometry. The range of concentrations (Bq kg-1 dry weight) for 238U, 226Ra, 228Ra, 137Cs and 40K in all investigated mushroom samples were from 0.12 to 12, 0.05 to 7.5, 0.14 to 14, MDC(<0.01) to 339, and 396 to 1880, respectively. Activity concentrations of 137Cs in mushrooms showed some variation between species sampled at the same site. To calculate soil to mushroom transfer factors, levels of radionuclide in 15 paired soil samples and mushrooms were also investigated. The median transfer factors for 238U, 226Ra, 228Ra, 137Cs and 40K were 8.32 × 10-2, 3.03 × 10-2, 6.69 × 10-2, 0.40 and 1.19, respectively. The results were compared with values of other areas.

At present, more than 30 countries and regions have established nuclear power station, and nuclear safety has become a problem that should be paid more attention in the development of nuclear energy in future. From the first nuclear power station of the world to the present, in the past 60 years of nuclear power development, there were once more than 10 nuclear accidents of different scales, especially were Chernobyl nuclear accident in 1986 and the Fukushima nuclear accident in 2011 which were two most serious seven grade nuclear accidents in mankind history. Therefore, nuclear accident, especially serious accident, has enormously affected society. And nuclear leak event could affect strategic direction of nuclear development of many countries, and involve how to ensure nuclear safety under the influence of special event and involve nuclear safety culture. Besides, it also provided valuable experience and lessons for international society about how to deal with nuclear accident. The safety of nuclear electric power generation is basic principle that must be persisted by competent department. And only when the nuclear safety is ensured, it can promote nuclear power to achieve enormous development.

Objective To equip a new type of portable electric refrigeration HPGe gamma spectrometer system and applying it to the field of radiation monitoring.Methods Introducing the portable electric refrigeration HPGe gamma spectrometer system on the aspects of system structure and supporting,and calibrating the system in energy and efficiency.Results This system has the characteristics of portability,high intelligent,and good line energy.We obtained the accurate efficiency calibration curve,which makes radionuclide content in environmental samples analysis more quickly and accurately.Conclusion The portable HPGe gamma spectrometer system has a very good prospect for the application in radiation monitoring,and it can play an important role in the nuclear emergency monitoring.

Objective To improve theγ-spectrometry analysis technology in water sample through the intercomparison conducted among the key laboratories. Methods To take part in the intercomparison of γ-spectrometry analysis in water sample organized by National Institute of Metrology ( NIM ) , the radionuclides of 238 U,226 Ra, 208 Tl, 228 Ac, 40 K, 241 Am, 137 Cs, and 60 Co in water sample were determined. The efficiency of the detector was calibrated renewedly by new standard source in 2015 and a new γ-spectrometry (BE5030) was used for sample measurement. Results Analysis and comparison of the three measurement results and the leading laboratory reference values showed that the results measured by γ-spectrometry ( BE5030 ) were better, especially for the natural radionuclides. The maximum En value between them and NIM reference value was only 0. 71. Conclusions The wide range energy γ-spectrometry (BE5030) has obvious advantages in the measurement and analysis of natural radionuclides. Due to the special structure of the wide range energy detector, its background interference is less in low energy area. This inter-comparison improved the accuracy of sample measurements and analysis, with good result achieved.

目的监测2015年北京地区室外近地面空气气溶胶中γ放射性核素组成与空气污染的关系。方法采用便携式Staplex TF1A型大流量空气采样器采集室外近地面空气气溶胶,滤膜为Whatman公司生产的空气监测用滤膜,使用实验室HPGeγ能谱仪测量分析气溶胶滤膜样品。结果样品中检测出的放射性核素包括 212 Pb和7Be,其中 212 Pb的活度浓度大约在10 -2 Bq/m~3的量级;~7Be的活度浓度大约在10-3Bq/m~3的量级;其他放射性核素均未检出。结论经与空气污染等指数进行分析发现, 212 Pb的近地面空气中放射性核素活度浓度水平与PM2.5、PM10和空气污染指数的相关性有统计学意义,成正相关关系。~7Be的近地面空气中放射性核素活度浓度与空气污染指数的相关性有统计学意义,是弱负相关关系。

目的 比较不同测量时间食品和饮用水中放射性核素的探测限值,为应对核与辐射突发事件提供参考.方法 使用同一台γ谱仪分别测量水、牛奶和菠菜的马林杯样品,每种样品测量的活时间分别为2、4、8、12、24、72 h,将分析得到的探测限值与国际原子能机构(IAEA)推荐的操作干预水平以及世界卫生组织(WHO)推荐的饮用水水质标准进行比较.结果 饮用水和牛奶样品2 ～72小时131 I、137Cs和134Cs测量结果范围分别为0.04～0.30 Bq/kg,0.05～0.34 Bq/kg和0.05～0.36 Bq/kg,新鲜菠菜样品的探测限略高于饮用水和牛奶样品.三种样品2～72 h测量结果均符合相关标准要求,但所得探测限值均随测量时间延长而减小.结论 在时间许可的条件下,尽量采用较长的探测时间可以增强检测能力,提高样品的检出率,但在应急情况下,应当进行代价利益分析,选择与可探测到的最低活度匹配的最佳测量时间.