氡的多参数测量用于非铀矿地质问题

在非铀矿地质问题中,常存在着一种或几种氡的弱异常(如²²²Rn、²²⁰Rn等).在选用测氡方法来解决这类问题时,要求它具有高灵敏度、高测量精度和多测量参数的特点。选用静电α卡法、α杯法的多参数测量技术,在圈定岩脉边界、区分岩脉性质、找寻蓄水构造、确定油田范围的应用中取得了明显的效果,     

用于资源勘查和环境监测的α测氡技术

近一个世纪以来,氡气测量一直是国内外众多学者的重要研究课题,早在二十世纪初叶α测氡就开始试用于地质工作,随着人类对铀矿资源需求程度的变化,特别在上世纪80年代以后,人们将放射性测量重点应用于非铀矿勘探地学领域,氡气测量技术和仪器设备经历了数次重要的发展阶段,用于土壤、空气和水中测量的瞬时法、累积测氡仪器设备已经形成有多个种类和型号.     

主动瞬时活性炭吸附土壤氡气测量方法初探

研究了主动式活性炭吸附土壤氡气测量方法。在氡室条件下,利用设计的取样装置对主动式活性炭吸附法中活性炭吸附能力、取样量、取样速度等影响因素及测量参数开展了实验研究,并进行了该方法与其他3种不同土壤氡气测量方法的野外对比实验,相对于传统的被动式活性炭累积测氡,该方法工作效率高,为土壤氡气测量在勘探找矿、环境监测等领域的应用提供了一种全新的测量方式。     

杯法测氡原理及应用

本文分析了α测氡方法及应用的现状,针对目前存在的问题,通过实验研究,提出了α杯法测氡技术。文中详细论述了α杯法测氡原理、功能、特点、工作方法和应用情况。结果表明:α杯法测氡的灵敏度高、操作简单、效率高、成本低、能够为寻找基岩地下水、探测隐伏地质构造、解决工程地质问题等提供了可靠依据,有进一步推广应用价值。     

氡气测量及其在寻找基岩地下水、地热和工程地质中的应用

应用氡气所测量,特别是静电α卡法,找寻基岩地下水和地热,解决工程地质有关问题,在我国取得了明显的效果.我们研究的静电α卡法是一种累积测氡技术,它具有灵敏度高,成本低,能在浮土覆盖厚,电磁干扰及噪声干扰严重,地形起伏大的山区、城镇工作,为开展水工物探、城市物探等提供了一种有效的物探方法.自82年以来,应用静电α卡法曾在我国廿多个省市,上百个地点进行过找水、找矿、找石油、解决工程地质问题、进行地质填图、考古等试验.结果表明,静电α卡法等测氡技术具有良好的地质效果与经济效益.     

218Po法找盲矿体初见成效

本文首先为寻找盲矿体介绍一种快速测氡方法——²¹⁸Po法。接着概述方法的工作原理、特点,以及找矿效果。然后从氡气运移角度出发,阐述了²¹⁸Po法找盲矿体的可能性。最后着重介绍²¹⁸Po法测量结果的解释方法。由此可以看出:²¹⁸Po法测量不仅可以用来找寻盲矿体,而且利用它的测量结果有可能定量预测盲矿体的埋藏深度与规模。     

寻找新构造裂隙水的新方法——210Po法

为了提高探测地下水的地质效果,近些年来国内外采用了放射性物探方法探测地下水,取得了较好的成果。目前采用的方法主要有γ法和α径迹法^[1]。比较起来,α径迹法的灵敏度较高,探测深度较大,应用于寻找新构造(指晚期构造)裂隙水^[2]的效果比γ法为好。     

四川新先达测控技术有限公司

<正>KJD-2000R测氡仪该仪器是一种新型的连续测氡仪器,属标准测量方法之一,它利用静电收集氡衰变子体进行累积测量,灵敏度高,现场获取结果,体积小、重量轻、测量时间短、探测器无污染、性能稳定。广泛适用于室内测氡、土壤中测氡、水中氡测量、水中镭测量。在地质隐伏断裂揭示、地质工程、建筑测     

关于氡测量标定装置(氡室)和测量单位的统一

本文介绍了作者研制的8505—I型氡室,该氡室可用于准确和快速标定多种测氡装置。作者提出了相应的标定方法,并测定了野外常用的10种氡探测器的标定系数。根据法定计量单位选用了贝克(Bq)和贝克/升(Bq/L)。相应作为各种氡测量的[放射性]活度单位和氡浓度单位。     

华东地区含煤岩系天然放射性水平与生态健康风险评价

本次研究基于地表γ辐射剂量率、氡放射性测量及²³⁸U、²³²Th、²²⁶Ra、⁴⁰K放射性核素测试,识别华东地区含煤岩系的放射性异常地层,评价区域典型煤矿区空气、固体、水体、植物介质的天然放射性水平。结果显示：赋存于石炭系、二叠系的普通煤田与赋存于寒武系的石煤矿区呈现显著差异的天然放射性水平。普通煤田矿区地表γ辐射剂量率、氡放射性测量值总体上处于本底水平范围,矿区固体介质、水体、植物样品核素含量处于正常水平,不存在放射性污染。华东地区石煤分布带,属于放射性γ辐射高背景区,石煤矿区的原煤、煤矸石、土壤、岩石等固体介质的²³⁸U、²²⁶Ra核素富集明显,并显示更为显著的空间变异性。区域石煤条带监测矿区居民源于γ外照射引起的吸收剂量均超过国际标准限值1 mSv/a,总有效剂量均超过了2 mSv/a,地下水总α、总β浓度为限值的10~30倍,放射性污染不容忽视。华东地区石煤矿区公众所受辐射剂量较高,矿区的地下水、建材、植物等介质已经出现零星的放射性污染,应加强石煤矿区放射性环境监测,及时采取适当的控制措施。     

趋势面分析法圈定氡异常

测氡技术能有效圈定煤炭气化燃空区范围。为了准确圈定氡异常的位置和范围,采用趋势面分析方法,以不同次数的多项式拟合氡元素的整体分布趋势;基于拟合度分析和F分布检验确定最佳趋势面多项式的次数,在此基础上进行残差(剩余)分析,识别局部异常,进而圈定氡值异常范围。以内蒙乌兰察布新奥集团煤炭地下气化燃空区测氡数据为例,验证了该分析方法在圈定地下气化燃空区范围方面的可行性。结果表明:该方法圈定的氡异常与验证钻孔点吻合程度好,明显优于使用传统方法圈定氡异常的方法,为低放射性地区氡异常的圈定提供了一种快速、简单并且有效的方法。      

丹凤地区花岗伟晶岩型铀矿区放射性水文地球化学特征及找矿效果

放射性水文地球化学找矿以其快速、简便、经济和高效的优点在丹凤地区花岗伟晶岩型铀矿勘查的各个阶段发挥了重要作用,浅层地下水放射性异常晕与含矿黑云母花岗伟晶岩分布范围一致,可用于圈定铀成矿远景区、普查区和详查区。近矿中深层地下水具有高U-Rn放射性水文地球化学特征,通过工程放射性水文地球化学找矿,可预测盲矿体大致位置,指导揭露工程布置。     

On radon emanation as a possible indicator of crustal deformation

Radon emanation has been monitored in shallow capped holes by a Tracketch method along several active faults and in the vicinity of some volcanoes and underground nuclear explosions. The measured emanation shows large temporal variations that appear to be partly related to crustal strain changes. This paper proposes a model that may explain the observed tectonic variations in radon emanation, and explores the possibility of using radon emanation as an indicator of crustal deformation. In this model the emanation variation is assumed to be due to the perturbation of near-surface profile of radon concentration in the soil gas caused by a change in the vertical flow rate of the soil gas which, in turn, is caused by the crustal deformation. It is shown that, for a typical soil, a small change in the flow rate (3 · 10⁻⁴ cm sec⁻¹) can effect a significant change (a factor of 2) in radon emanation detected at a fixed shallow depth (0.7 m). The radon concentration profile has been monitored at several depths at a selected site to test the model. The results appear to be in satisfactory agreement.     

Comparative analysis of continuous radon sensors in underground environments

Four different continuous radon (²²²Rn)-detection systems have been compared in underground environments, namely three subhorizontal tunnels excavated for groundwater exploitation. Within observational uncertainties, all sensors detected the same concentrations of radon in the air of the tunnels, regardless of the methodology used to measure this radioactive gas. In this sense, the choice of continuous long-term radon monitoring sensors in underground tunnels is constrained by factors such as robustness of the instrumentation, power supply and cost, rather than the sensitivity of the detection methodology. This is particularly important for the monitoring of radon in the context of seismo-volcanic surveillance, where the harsh environmental conditions of the monitoring sites and the absence of electrical power supply are key factors to take into account.     

氡气勘查地球化学技术的研究与应用--氡气异常在百色盆地的指示效果

阐述在我国南方百色地区复杂的地球化学景观条件下，氧气勘查地球化学技术能否有效地发现地下油田的分布范围并准确地圈出它们埋藏位置的应用研究成果。指出在百色盆地不同类型油田上方和周边都有较好的氧气异常显示，且氧气异常分布形态特征与笔者建立的异常模式相吻合。认为氧气勘查地球化学技术在我国南方复杂景观条件下有较好的指示效果。     

A comparison of field and laboratory analytical methods for radon site investigation

Soil-gas radon measurements provide a valuable tool in assessing probable indoor radon levels on a regional basis. However, in Great Britain, seasonal weather changes can cause large changes in soil-gas radon concentration. Although this does not significantly constrain systematic radon potential mapping programmes, it does cause difficulties in responding to ad-hoc requests for site-specific radon investigations. The relationship between soil-gas radon and gamma spectrometry measurements made in the field with radon released from a representative sample of soil in the laboratory has been investigated as part of a program to develop a method of radon potential mapping and site investigation which can be used at any time of the year. Multiple soil and soil-gas samples were collected from sites underlain by bedrocks with widely varying radon potentials. For each geological unit, sites both free of and covered by glacial drift deposits were sampled. Soil and soil-gas samples were taken at the same depth of 60–100 cm. The effectiveness of these radon site investigation procedures has been evaluated by studying the relationship between the soil-gas radon, gamma spectrometry and radon emanation data with an independent estimate of the radon risk. The geologic radon potential (GEORP), which is the proportion of existing dwellings which exceed the UK radon Action Level (200 Bq m⁻³) for a particular combination of solid and drift geology within a defined geographic area, has been used for this study as the independent estimate of radon risk. Soil-gas radon, radon emanation and eU (equivalent uranium by field γ spectrometry) are all good geochemical indicators of radon risk (GEORP) in Derbyshire but only soil-gas radon correlates significantly with GEORP in Northamptonshire. Radon in soil gas discriminates more effectively between sites with different radon potential in Northamptonshire if soil permeability is also taken into account. In general, measurement of soil-gas radon in the field provides the most universally applicable indicator of radon potential. If soil-gas radon concentrations cannot be determined because of climatic factors, for example when the soil profile is waterlogged, measurement of radon emanation in the laboratory or measurement of eU can be used as radon potential indicators in some geological environments. This applies particularly in areas where the soil composition rather than the composition and permeability of the underlying rock or superficial deposits are the dominant controls of radon potential. It appears, therefore, that it may be necessary to use different radon site investigation methods according to the specific factors controlling radon emanation from the ground. In some cases no method will provide a reliable indicator of radon risk under unfavourable climatic conditions.     

Collection of radon decay products — a uranium exploration technique

The spontaneous deposition of short-lived radon decay products onto solid surfaces (“collectors”) provides the basis for a simple and efficient way of prospecting for uranium. The alpha activity of two of the decay products, ²¹⁸Po and ²¹⁴Po, can be measured by conventional counting techniques following the exposure of a collector to a radon source. Laboratory studies have shown: (a) radon decay products can be collected on a wide variety of materials; (b) the number of radon decay products increases with the collector surface area; (c) a negative charge applied to the collectors enhances the number of decay products collected; (d) the shape of the collectors is relatively unimportant; and (e) reproducibility is about ± 5% of the measured value.Field tests on known uranium anomalies involved suspending collectors for an overnight exposure, in either covered holes or inverted containers buried in soil. Subsequent removal of the collectors was immediately followed by counting the alpha activity. Anomalies were readily detected at three different test sites. Replicate measurements at selected sites both on an hour-to-hour and on a day-to-day basis showed remarkably good agreement. Some anomalies were also outlined using activity measurements from collectors suspended above soil aliquots in sealed containers.Because the half-lives of two of the thoron (²²⁰Rn) decay products are much longer than those of the radon (²²²Rn) decay products, a thoron correction can be applied to the original activity measured from the collectors, thus discriminating against thoron in thorium-rich terrains.The counting of radon decay products deposited onto collectors is an effective method for delineating radon anomalies in uranium exploration. The field techniques are simple to apply, and results are available after very short exposure times (about 18 hours) and after short counting intervals (5 minutes).     

应用测氡法勘探岩性油藏

岩性油藏在地表可产生放射性氡异常,呈环状模式。通过典型地区剖析和应用,结合钻探成果证实测氡法效果明显。应用该方法能够评价砂岩体含油性,上部油层的分布和进行含油有利区预测。