H-90B微机γ能谱比活度测量仪

本介绍了H-90B微机γ能谱比活度测量仪的研制方案、仪器组成特点及主要技术指标；简述了仪器的工作原理，工作条件及测量方法；最后，介绍了其在现场检测建筑材料放射性比活度方面的应用情况。     

吉林陨石宇成核^26Al修正实验

本文报道了用低本底Ge(Li)γ谱仪重新测量吉林陨石2号和5号样品中宇宙成因核素^24Al的比活度，对以前发表的结果进行了修正。测得的^26Al平均比活度为32．4dpm／kg，与国外报道的平均值在谋差范围内符合，同时，估算和讨论了吉林陨石的宇宙线暴露年龄。     

基于SNIP算法扣除γ能谱本底的探讨及应用

在自然γ能谱全谱分析中,为了分离无用信息及提高解释精度,须进行γ全谱连续本底的自动扣除。介绍了γ能谱本底的来源及特征,探讨了SNIP算法扣除γ能谱本底的数学原理及过程,重点开展了SNIP方法在γ能谱本底扣除中的初步应用。通过对三个不同能量的全能峰的比较分析,指出应根据γ能谱中谱峰宽度的差异,选择合适的变换宽度,以便获得最佳的全谱本底扣除效果。实验证明,该技术可应用于自然γ能谱测井的软件处理平台中。     

青岛市地表天然放射性水平及其主控因素特征

通过对青岛市1500km^2范围内大密度土壤放射性核素（^238U、^232Th和^40K）和地表γ辐射测量,系统深入地研究了其放射性特征、分布规律及其影响因素。结果表明,青岛市土壤中核素^232Th和咏的放射性比活度偏高,而^238U偏低。地表γ辐射吸收剂量率（平均值91．87nGy·h^-1）略高于全国和世界平均值,研究发现地表93．14％的γ辐射来自地面放射性核素^238U、^232Th和^40K）的．γ辐射,其中^232Th和^40K的贡献占81．21％,是主要的贡献者。地质背景是影响地面γ辐射吸收剂量率的主要因素,燕山期各类花岗岩是导致青岛市区-王哥庄-带γ辐射吸收剂量率偏高的主要原因;同时环境因素（路面材料、地貌景观）对地表γ辐射吸收剂量率也存在一定影响。虽然研究区的γ辐射吸收剂量率较高,但其年有效剂量（0．56 mSv）远低于公众照射年剂量当量限值1.0 mSv,人居环境基本不受影响。     

冀北等地区车载γ能谱方法找金的应用研究

车载γ能谱方法找金是寻找隐伏金矿床的物化探新技术。用它可有效地预测区域金成矿远景区。在冀北等地区（４．９１万ｋｍ￣２）采用车载γ能谱测量方法，取得地质体内６３４１６个γ能谱测点数据，按地质体大小使用滑动滤波技术，处理区域地质体中的γ能谱数据并绘制了参数分布特征图件。在深入研究γ能谱参数分布特征所反映的区域金成矿地质环境的基础上，建立了一套与区域金成矿相关的γ能谱组合参数，提取了γ能谱参数特征信息。结合地质资料，研究工作地区的金成矿地质环境，预测了两片远景区，部分地区经验证，见有金矿化。研究结果表明，车载γ能谱方法用于区域找金是一种快速、节资、有效的方法。     

黄河三角洲北侧潮滩的^(7)Be分布及侵蚀特征北大核心CSCD

测定了黄河口三角洲获取的表层样ZK1(高潮滩)、ZK2(潮上带)与ZK3(陆上三角洲)的^(7)Be含量,利用降雨量-^(7)Be大气沉降通量公式估算了黄河三角洲区域的^(7)Be大气沉降量,而后根据^(7)Be的比活度分布、沉积环境以及沉积物粒度探讨了研究区的侵蚀特征。实验结果表明:ZK3的^(7)Be最大可测得深度为6 mm,ZK2为2~4 mm,ZK1为0~2 mm,3个样点的^(7)Be比活度均在0~2 mm内达到最大值。ZK3的^(7)Be比活度随深度呈指数式衰变,且其面积活度值与沉积通量估算值相符,表明ZK3处沉积环境稳定,也验证了沉降公式在黄河三角洲的适用性。进一步结合沉积速率与沉积时间对3个样点进行对比分析发现,黄河三角洲的高潮滩和潮上带在风暴潮来临时分别经历海水和风力的侵蚀作用,2018年11月20日至2019年5月3日样点ZK1处沉积平衡(B)为−0.4 cm,样点ZK2处沉积平衡(B)为−0.2 cm,反映了风蚀作用强度弱于海水侵蚀作用。研究区在冬半年内表现为净侵蚀但整体地势变化平缓,且侵蚀强度应具有冬半年大于夏半年的季节性特征。     

中国和世界几个主要国家航空γ能谱测量评述

本文概述了世界几个主要国家如中国、加拿大、美国和前苏联航空γ能谱测量的发展情况。文内重点介绍了中国航空γ能谱测量的现状和加拿大、美国及前苏联3国在航空γ能谱测量方面的重大事件和主要技术特点，总结了近10多年来世界范围内航空γ能谱能量方面的重大技术进展，找出了我们的差距及其产生的原因，提出了加速发展我国航空γ能谱测量的奋斗目标。     

用γ能谱测量确定铀尾矿氡析出率的可行性

本从氡析出率的理论计算和野外实测的大量分析结果，探讨了γ 能谱测量镭比活度计算铀尾矿氡析出率的可行性。     

γ总量、γ能谱测井曲线的计算机解释初步试验

γ测井曲线的解释是铀矿勘探工作中一项十分重要的经常性工作。在我国,这项工作至今仍停留在手工解释状态,而国外,自六十年代起就开始采用电子计算机解释。它不仅比手工解释大大提高了效率,而且能得到更接近于矿体实际情况的铀含量分布数据,为进一步利用γ测井资料提供了可能性。当磁带记录的数字自动测井仪开始广泛使用时,它将更充分地发挥出高效率的优越性。为了取得经验,我们用TQ-16算法语言编制了γ总量和γ能谱测井曲线解释程序,在七○九计算机上进行了初步实践。对三个模型井的γ总量、γ能谱测井曲线及三个钻孔约273米γ总量测井曲线和208米γ能谱测井曲线的解释均获得了令人满意的结果。此外,考虑目前我国铀矿勘探中尚无磁带记录的数字自动γ测井仪的现状,我们编制     

航空γ能谱测量资料在水成铀矿化综合预测工作中的应用

本文通过对马林诺夫矿床为标准物进行的航空γ能谱测量，以及库伦达盆地、秋雷姆－叶尼寒盆地航空γ能谱资料的解译证实了天然放射性核素再分布区的控矿作用；指出了地台条件下，运用水文地质资料，可发现水成铀矿化形成过程中的一些特征；进一步说明了航空γ能谱研究和水文地质研究之间的互补生。文章最终确定了天然放射性核素再分布区是水成铀矿化的普查标志，1：200000为最佳的研究比例尺。     

运用1∶25万化探数据进行区域天然放射性填图评价

以1∶25万化探数据为切入点,在分析全国各城市天然放射性水平特征的基础上,运用放射性填图评价技术研究了成都平原天然放射性水平分布特征。结果表明:研究区环境天然放射性核素238 U、232 Th、40 K含量频数均呈正态分布,数值均在正常本底范围内;238 U比活度总体上低于全国平均水平,232 Th和40 K比活度总体上高于全国平均水平;研究区天然放射性辐射水平、γ射线照射量率、吸收剂量率、年有效剂量当量均低于世界和全国的平均水平;研究区γ射线内、外照射指数均在国家限量标准控制范围之内。     

Investigation of natural background radiation of sediments in Rameswaram Island,Tamil Nadu,India

The aim of the study is to assess the natural background radiation in and around Rameswaram Island. In this context, samples were collected to measure the gamma radiations of ²³⁸U, ²³²Th, and ⁴⁰K using NaI(Tl) detector-based gamma ray spectrometer. The average activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K are noted to be well below the world average values. The calculated absorbed dose rate, radium equivalent activity, and hazard index values were below the prescribed limit. The grain size of the sediment was analyzed following Trefethen’s nomenclature, and its correlation with the natural background radioactivity was studied. The sample that contained clay show elevated activity of ⁴⁰K. The percentage of heavy minerals shows concomitant variation in natural radioactivity, especially in the activity of ²³⁸U and ²³²Th.     

Distribution of 238U, 232Th and 40K in plutonic rocks of Greece

One hundred and twenty one samples from every major plutonic body (mainly granitic) of Greece have been analyzed by γ-ray spectrometry to determine the specific activities of ²³⁸U, ²³²Th and ⁴⁰K (Bq/kg). The range of the activity concentrations of these radionuclides was 2.3–266.4, 1.8–375.5 and 55.0–1632.0 Bq/kg and their average values were 79.2, 85.3 and 881.4 Bq/kg respectively. Any possible connection between the specific activities of ²³⁸U, ²³²Th and ⁴⁰K and some characteristics of the studied samples (age, rock-type, colour, grain-size, occurrence and chemical composition) is investigated. Samples of particular colour, rock-type, occurrence and chemical composition have been identified for their distinctive levels of natural radioactivity, while age and grain-size do not affect the concentrations of ²³⁸U, ²³²Th and ⁴⁰K. The range of the Th/U ratio was 0.7–12.69. This great variation in the Th/U ratios, especially when it is found among the samples of the same pluton, is also discussed and explained by alteration and tectonic–metamorphic processes.     

Study on the natural radioactivity level of stone coal-bearing strata in East China

Based on γ-radiation dose rate and radon concentration measurements and ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K radionuclide testing, this study identifies the radioactive anomalies of stone coal-bearing strata in East China and evaluates the natural radioactivity levels in the air, solid, water and plant media in the typical area of the regional stone coal-bearing layers. The stone coal-bearing strata in East China occur in the lower Cambrian system along the margin of the Yangtze block; additionally, the radioactive anomaly area is sporadically distributed in the stone coal-bearing layers. The background values of ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K are higher in the stone coal-bearing areas, and the spatial distribution of these natural radionuclides shows significant variability. ²³⁸U and ²²⁶Ra clearly accumulate in the coal, coal gangue and soil and are the main sources of the environmental radiation in coal mines. The γ-radiation shows a higher background value in the stone coal-bearing area, and this radioactive pollution cannot be ignored. Typically, the effective dose of γ-radiation exceeds the limit value of 5 mSv/a, and the total α and total β concentrations of the groundwater are 10–30 times the limit value at some points. The residents near the mining area are subjected to a higher radiation dose, and the groundwater, building materials, and plants have been contaminated by the radioactive pollution sporadically through time. It is necessary to strengthen the monitoring work of radioactive environments and to take appropriate control measures.     

Radiological monitoring and statistical approach of primordial and anthropogenic radionuclides in surface soil of Mami-water site in the Western Cameroon

The study referred to measure activity concentrations of some primordial radionuclides and anthropogenic of ¹³⁷Cs in soil samples of Mami-water in the Menoua subdivision, Dschang employing gamma-ray spectrometry-based characterized Broad Energy Germanium (BE6350) detector and a comparison of radiological and safety impact parameters on human due to primordial radioactivity in soil with some internationally approved values. In addition, statistical analysis of primordial radionuclides of ²²⁶Ra, ²³²Th and ⁴⁰K was performed to evaluate the distribution and the interrelation of radionuclides. Samples were randomly collected from a depth of about 0 to 5 cm from the top surface layer. Each of the sampling points was considered as being overlaid with a grid and subdivided into cells. The observed radioactivity level of ²²⁶Ra, ²³²Th and ⁴⁰K in the investigated soil samples was compared with some published data available in some countries including Cameroon and observed varying within some reported data of radioactivity in soil from bauxite ore deposit. ²³⁵U and ¹³⁷Cs were found in very few samples with a very low average of activity concentrations. In the majority of the samples, the observed radiological safety parameters seem to be greater than the internationally approved values. Consequently, using bricks made of soil as building materials might lead to an increase in radiation risk for the population. Multivariate statistical analysis of activity concentrations of primordial radionuclides performed showed an asymmetrical distribution with more peaked than Gaussian distribution and relatively flatter distribution of radionuclides in soil. In addition, a good positive interrelation between ²²⁶Ra and ²³²Th was observed and a weak negative one observed between ⁴⁰K and ²²⁶Ra–²³²Th.     

Natural radioactivity levels and evaluation of radiological hazards from Beni Haroun dam sediment samples,northeast Algeria

Levels of naturally occurring radioactivity in sediment samples of Beni Haroun dam have been investigated. The activity concentrations of ²³⁸U and ²³²Th decay chains and ⁴⁰K primordial radionuclide have been measured using high-resolution HPGe detector. Activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K radionuclides were found in the ranges 9–66, 14–37, and 177–288 Bq/kg with the mean values 24.67, 25.98, and 208.10 Bq/kg, respectively. Radiological hazard parameters were estimated based on the activity concentrations for ²²⁶Ra, ²³²Th, and ⁴⁰K to find out any radiation hazard associated with the sediments. Correlation studies between pairs of radionuclides were performed and discussed, and the obtained results are compared with international recommended values.     

青岛市地表伽玛辐射特征及环境影响评价

对青岛市1 500 km 2范围内大密度土壤放射性核素和地表γ 辐射测量,系统深入研究了其放射性特征、分布规律及其影响因素。结果表明,青岛市土壤中核素232 Th 和40 K 的放射性比活度偏高,而238U 偏低。地表γ 辐射剂量率( 平均值91. 87 nGy /h) 略高于全国和世界平均值。研究发现,地表 93. 14%的γ 辐射来自地面放射性核素238U、232 Th 和40K 的γ 辐射,其中232 Th 和40K 的贡献占81. 21%,是主要的贡献者。地质背景决定地面γ 辐射剂量率值,燕山期各类花岗岩是导致青岛市区-王哥庄一带γ 辐射剂量率偏高的主要原因; 同时环境因素( 路面材料、地貌景观) 对其剂量率也存在一定影响。虽然研究区的γ 辐射剂量率较高,但其年有效剂量( 0. 56 mSv) 低于公众照射年剂量当量限值 ( 1. 0 mSv) ,人居环境基本不受影响。     

Evaluation of dose parameters and radiological hazards in gravel samples of Konyaaltı Beach,Antalya

It is important to know the distribution and transfer of radionuclides such as uranium, thorium, and potassium, which exist naturally in the environment we live in. For this reason, measurements of these natural radionuclides have been carried out for 15 gravel samples collected from Konyaalt? Beach, Antalya. In order to measure the natural activity concentrations of potassium-40, uranium-238, and thorium-232 radionuclides, we performed the measurements by applying a gamma spectrometry method with a “3?×?3” NaI(Tl) detector, which is a multichannel analytical detector in the Suleyman Demirel University gamma spectrometry laboratory. The minimum, maximum, and mean values for the ²²⁶Ra activity concentration were measured as 19.74 Bq/kg, 37.03 Bq/kg, and 31.64 Bq/kg, respectively. The minimum, maximum, and mean values for the ²³²Th activity concentration were measured as 12.76 Bq/kg, 34.32 Bq/kg, and 26.67 Bq/kg, respectively. The minimum, maximum, and mean values for the ⁴⁰K activity concentration were measured as 196.37 Bq/kg, 421.13 Bq/kg, and 350.42 Bq/kg, respectively. Dose parameters and radiation damage indices were calculated using experimentally measured activity results and the resulting dose and hazard index values were compared with the determined limit values. It can be concluded that no risk may threat in terms of the hazard index values. In addition, all results obtained in terms of calculated dose values except for annual gonadal dose are below the recommended limit values.     

Natural radionuclide survey in the coastal strip of the 290 Ramsar site,Uruguay

An initial on-going survey of the activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K for sand samples collected within the coastal strip of 290 Ramsar site evaluated the external hazard index, the outdoor annual effective dose equivalent and the radium equivalent activity, to elucidate potential risks for the resident inhabitants. The range of mean activity concentrations in the whole area for ²²⁶Ra, ²³²Th and ⁴⁰K were between 4.12?±?0.26 and 48.3?±?1.4, 5.47?±?0.55 and 194?±?13, 77.7?±?4.2 and 445?±?18 Bq kg^?1, respectively. The Barra de Valizas–Aguas Dulces region had the highest activity concentrations of ²²⁶Ra and ²³²Th. The annual effective dose equivalent for this region was higher than the mean worldwide value, whereas it is lower than the recommended values for public exposure.