AlphaGUARD测氡仪对BG2015R测氡仪标定的探索

氡对地震前后地层应力变化反应较为敏感,是示踪构造与地震活动的一种有效的化学元素。氡观测在我国地震前兆流体观测手段中占很大权重,但由于近年来仪器老化及更新换代较多,许多台站测氡仪的标定工作受到制约,因而影响了氡观测资料的准确性和可靠性。本文利用高精度的AlphaGUARD测氡仪,分别采用含有一定浓度的新鲜井水、固定源对宁德一号井BG2015R测氡仪进行标定实验,其结果是新K值与旧K值相对误差分别为2.83%和1.1%,标定结果符合中国地震台网的观测要求;同时对标定实验中AlphaGUARD测氡仪、BG2015R测氡仪测值进行了均值、一致性等指标计算分析,给出了对两套仪器标定时的取值建议。文中所述的标定实验的流程和方法可以为在网运行测氡仪的标定提供一定的技术参考。     

测氡仪器固体源标定法

引言 目前我国地震水氡观测台网,在观测工作中,用测氡仪器进行定量测量或用绝对单位来表示测值结果时,都必须对所用测氡仪器进行精确的标定。水氡观测技术规范也明确规定了,每年要对台站所用的测氡仪器进行定期标定。另外,测氡仪出现故障,经检修更     

FD-105K测氡仪的技术改造及其标定器的研制

本文较详细地阐述了FD-105K测氡仪技术改造的思路并对测氡仪标定器的研制及应用作了介绍。     

新型流气式固体氡源用于氡仪器标定的实验研究

GD-L2流气式固体氡气源是一种能产生确定量氡气的发生器,它利用连续恒定的空气流过特殊的固体含镭物质,形成稳定氡浓度的气流源,既可标定间歇取样的测氡仪又可以标定连续测氡仪。对固体氡气源的原理、标定方法、安全性能等进行论述,着重对多次标定的结果进行对比分析,提出影响固体氡气源稳定性的因素及其解决方案。通过两年来的标定及实验,认为该装置可以用于FD-125型氡钍分析器及SD-3A型数字化自动测氡仪的检查标定工作。     

宁波站DDL-2与FD-105K测氡仪对比观测研究

测氡仪对比观测研究是探索仪器运行规律和提供可靠地震研究数据的支撑。文章基于使用AlphaGUARD P2000测氡仪作为无源标定仪器对DDL-2测氡仪进行溶解氡的校准实验,开展DDL-2测氡仪氡浓度响应研究以及DDL-2测氡仪和FD-105K测氡仪对比观测研究。结果表明：(1)校准K值的偏差值都在4.827 6%以内,满足目前地震监测观测技术要求和仪器标定要求;(2)DDL-2测氡仪可描述动态的水氡浓度,使用Origin 2018数据分析软件对氡浓度绘制拟合曲线,为氡值变化过程提供数学模型,鼓泡过程中水氡浓度经历迅速上升期、平缓期和稳定期,稳定后氡浓度变化幅度约为5.0 Bq/L,并且变化形态不尽相同;(3)使用Origin 2018对比分析数据,发现DDL-2测氡仪与AlphaGUARD P2000测氡仪较FD-105K测氡仪氡浓度日变化响应更灵敏且氡测值曲线吻合度更高。     

SD-3系列测氡仪检查源在FD-125测氡仪坪曲线测试工作中的实验研究

在FD-125测氡仪检查工作中,需使用α检查源或固体氡气源测试高压-坪曲线来确定及检查最佳工作高压。由于厂家提供α检查源测试高压-计数率坪曲线坪区不明显、氡源故障,造成在FD-125测氡仪检查工作中难以对工作高压进行检查的问题。考虑到SD-3系列测氡仪其工作原理与FD-125测氡仪基本一致,SD-3系列测氡仪故障后所配置α检查源仍然可用,因此,将SD-3测氡仪检查源用于FD-125测氡仪的检查工作,经测试效果较好。     

测氡仪的标定及K值使用中存在的一些问题

观测地下水中氡含量的变化是水文地球化学方法监测预报地震的重要手段之一,也是探索地震孕育、发生的重要窗口。乌鲁木齐流体综合台采用FD-125型测氡仪观测地下水中氡含量的变化进行地震监测预报研究已进行了20多年。在水氡观测中,为保证观测资料的准确可靠,每年都要对测氡仪进行标定。标定得出的K值是测氡仪闪烁室的标准系数,对水氡测值起着纠正偏差的作用。从多年的标定工作和观测资料来看,     

闪烁法测氡仪校准与标定探究

以SD-3A型数字化测氡仪的校准和标定实验数据为依据,具体分析使用标准氡室的方法进行校准和使用固体氡源标定的区别,详细阐述两种方法对仪器比例因子进行修正的差异和原因,对闪烁法测氡仪常数的校准提出建议性方法。     

SD-3A自动测氡仪标定问题的探讨

本文对SD-3A数字化自动测氡仪标定中发现的一些问题进行了探讨并提出建议。     

福州地震台P2000测氡仪试测实验分析

对P2000与FD-125测氡仪进行为期一个半月的同步观测对比,并对P2000测氡仪该装置是否适用于地震氡观测及氡气标定器的刻度校正进行测试实验,根据观测的数据进行归纳和总结.结果表明,P2000测氡仪稳定性较好,操作使用简单,一次性充电可以连续使用十几个小时,较适用于野外观测.缺点是该测氡1次只能测1个水样,如果要测两平行样要六七个小时,时间相对较长.对观测的数据对比分析,发现虽然P2000测氡仪测值低于FD-125氡钍分析器的测值,但整体形态和趋势变化基本一致.     

Radon variation in groundwaters in the Campi Flegrei Caldera (southern Italy) during and after the 1982–1984 bradyseismic crisis

Groundwater Rn concentration has been monitored at several sites in the Campi Flegrei Caldera since the time of the last episode of bradyseismic activity. The results concerning the period 1983–88 indicate that the Rn concentration is spatially variable due to the different chemico-physical characteristics of the waters or structural features. Rn concentration is generally influenced by the long-term changes of meteorological factors. Rainfalls appear to affect the Rn content of the most superficial aquifers. Several short-term spike-like Rn anomalies have been detected both during and after the period of the bradyseismic crisis. They do not show correlation with temporal changes of the pH and/or temperature of waters. A systematic correlation between Rn anomalies and episodic strong rainfall events is also absent. Furthermore, a clear relationship between Rn spikes and both uplift velocity changes and seismic activity has not been found.The overall evidence makes it very difficult to understand the temporal changes of groundwater Rn concentration that have occurred during and after the 1982–84 bradyseismic crisis. Nevertheless, a clear causal relationship between Rn concentration and the dynamics of the bradyseism is observed in some monitored sites. Its appearance may have been favoured by the low Rn concentration in the groundwaters during periods of quiescent activity.     

五大连池地下浅层气体与火山及断裂关系的初步研究

用气体化学方法,在五大连池药泉山、卧虎山、笔架山、老黑山、东、西龙门山之间进行了氡、钍放射性气体测量,布设了12条测线。测量结果,发现Rn、Th浅层气体和某些断裂关系密切。尤其是药泉山周围和老黑山—笔架山之间,氡、钍放射性气体表现出异常高值,Rn、Th的含量大大高于区域背景值。初步认为药泉山周围地区为强构造活动区,Rn、Th等火山断层气和断裂活动及火山活动有密切关系。     

Captive balloon measurements of radon 222 and its daughter ions

Summary An instrument for use with a captive balloon has been developed for the investigation of the vertical distribution of²²²Rn and its daughter ions of high mobility. The system consists of a light weight ion collector of the Gerdien type and an automatic air sampler. Simultaneous collections of²²²Rn and its daughter ions having mobilities of known limits makes it possible to determine the concentration of the radioactive ions relative to the ambient concentration of²²²Rn in different atmospheric conditions in the air layer adjacent to the ground where aircraft and tower measurements are not practicable. Vertical profiles taken over a mountain ridge in a well-mixed atmosphere show almost constant concentrations of²²²Rn and its daughter ions with altitude. In some cases a slight increase in the concentrations of²²²Rn and its daughter ions with altitude has been observed. The radioactive ion concentration relative to the ambient concentration of²²²Rn in the boundary layer is of the order of 3%.     

The effect of CO2 on the measurement of 220Rn and 222Rn with instruments utilising electrostatic precipitation

In some volcanic systems, thoron and radon activity and CO₂ flux, in soil and fumaroles, show a relationship between (²²⁰Rn/²²²Rn) and CO₂ efflux. It is theorized that deep, magmatic sources of gas are characterized by high ²²²Rn activity and high CO₂ efflux, whereas shallow sources are indicated by high ²²⁰Rn activity and relatively low CO₂ efflux. In this paper we evaluate whether the observed inverse relationship is a true geochemical signal, or potentially an analytical artifact of high CO₂ concentrations. We report results from a laboratory experiment using the RAD7 radon detector, known ²²²Rn (radon) and ²²⁰Rn (thoron), and a controllable percentage of CO₂ in the carrier gas. Our results show that for every percentage of CO₂, the ²²⁰Rn reading should be multiplied by 1.019, the ²²²Rn radon should be multiplied by 1.003 and the ²²⁰Rn/²²²Rn ratio should be multiplied by 1.016 to correct for the presence of the CO₂.     

地震地球化学某些前兆机理的模拟实验研究

本文通过氡射气性能的压力实验,氡射气分配系数实验和岩石的溶滤实验等,对地下水氡及其它地震地球化学前兆机理进行了探讨。实验表明:氡射气的最高值发生在岩石严重破裂时;岩石射气性能高低与其本身的铀含量成正比;岩石在压力作用下射出的氡气在水中的分配大于在气相中的分配;岩石在饱和CO_2水中和压力作用下的溶滤程度要比在纯蒸馏水中和常压下大得多。因此,地震前地下水氡浓度和水中离子组分和气体组分会出现异常变化,而这种变化既与应力作用有关,又与地球内部水-气-岩系统在地震孕育过程中的物理化学作用有关     

Summit outgassing as indicated by radon, mercury and pH mapping, Kilauea volcano, Hawaii

Surface geochemical mapping of Rn, Hg and pH on the summit of Kilauea volcano, Hawaii, has shown some of the characteristics of outgassing. Rn concentrations measured in shallow ground gas are highest (10 to 155 units, i.e. up to 0.016 nCi/l²²²Rn) over deep structures associated with the summit caldera, low (1 to 5 units) over the upper rift zones (which are underlain by shallow intrusions) and low to negative (1 to -3 units) over most of the volcanically inactive peripheral areas. High Rn concentrations were measured over peripheral well-developed structures such as the Kaoiki and Koae fault systems (45 and 12 units, respectively). The pattern of Rn values broadly suggests the existence of a summit-wide convection system interrupted locally by specific permeable structures. The low pH (3.5 to 5.6) of soils over the caldera is suggested to be largely due to the sulfurous component of the ground gas. The low concentrations of Hg (5 to 80 ppb) in these soils are postulated as being partly a function of subsurface complexing of Hg with the abundant sulfur. The shallow intrusions below the upper rift zones appear to have outgassed much of their sulfur content, so soils in these areas are only slightly acid (5.6 to 6.2), allowing the accumulation of Hg to concentrations of several thousands of ppb. These conditions change during extrusive (and intrusive) events with the increases in shallow subsurface temperatures and volatiles in ground gas producing an increase in Rn concentration, and a decrease in soil Hg due to volatilization. After such events, Rn concentration decreases, and soil Hg increases significantly.     

呼和浩特地区隐伏断层土壤气氡、汞地球化学特征

根据呼和浩特地区隐伏断层土壤气中氡、 汞的浓度, 探讨了断层的气体地球化学特征及其确定隐伏断层的方法。 在呼和浩特地区8条测线上进行了土壤气中氡、 汞浓度野外现场测量, 共2014个测点。 测量结果表明: 土壤气中氡浓度背景值为2238.7～3715.4 Bq/m³, 土壤气汞浓度背景值为21.1～79.4 ng/m³。 在8个地球化学剖面中有7个在断层带上发现了异常, 其土壤气氡、 汞异常强度一般是背景值的1.7～10.3倍。 根据断层带上土壤气氡、 汞异常特征确定了断层的具体位置。 土壤气氡、 汞测量是隐伏断层探测中非常有效的手段。     

山西地震带北段与张家口——渤海地震带不同深度CO_2和Rn气体通量的差异性

2014年在山西地震带北段和张家口—渤海地震带布设35个测量剖面,测量土壤气CO_2、Rn浓度及深度20 cm、1 m的CO_2和Rn通量。测量结果表明:(1) CO_2、Rn浓度与深度20 cm、1 m的CO_2、Rn通量的平均值和最大值变化趋势大致相同,均呈自西向东的增大趋势;(2)深度20 cm、1 m的CO_2和Rn通量相关性均不明显,但1 m深的CO_2、Rn通量明显较高;(3) CO_2和Rn浓度、通量变化主要与区域复杂的地震活动性和断层活动性有关,主要受到地表化学成分和区域岩石地球化学影响。     

Release of 222Rn from some soils

Measurements have been made of ²²²Rn release from diverse soils in the region surrounding Malaga, Spain. These flux measurements were carried out by two methods. A direct method using a static chamber technique and another indirect method obtained from concentration profile measurements of ²²²Rn in the soil air. The effects of meteorological variables and other parameters on ²²²Rn flux were studied. The factors that most affected the instantaneous value of ²²²Rn release were humidity and soil thermal gradient. The directly measured ²²²Rn fluxes at investigated sites are higher than ²²²Rn fluxes derived by the indirect method.