饮用水室内空气中222Rn的一个来源

近十余年来,关于饮用水中222Rn对室内空气中222Rn浓度贡献,已有一些报道。本文目的是利用住房空间体积、换气速度、用水速度和氡由水向空气的转移效率等,进行综合考虑,预测水中222Rn浓度所致室内空气中的222Rn浓度。     

饮用水中~(222)Rn的测定

~(222)Rn是由~(22?)Ra衰变产生的一种惰性气体.它的衰变是以发射α粒子进行的,但其短寿命子体~(214)Pb和~(214)Bi是γ辐射体,因此一旦达到放射性平衡,~(222)Rn的浓度可以通过其子体的γ谱探测来确定.实验用此方法测定了意大利波代诺内地区饮用水中~222Rn的浓度.方法:选用一种3升铝制的配有硅密封园环的Mainell烧杯.为尽量减少氡的损失和达到放射性平衡,样品必须在避免湍流的条件下收集.井水样品是把烧杯完全浸入水中采集的,而管道水的采集是     

利用液体闪烁测定法定量分析空气中的~(222)Rn和~(220)Rn

研究了应用液体闪烁计数器(LSC)定量分析空气中Rn的基本条件。用含液体闪烁体(LS)的简单装置吸收Rn,以(LSC)测定放射性。在LSC的积分计数法中,采用焠灭校正法作为求得零水平外推值的方法是适用的。能把检出限降到1/10。使用商售大容量的LSC,测定100分钟时,~(222)Rn的检出限为0.1pCi·L~(-1)(2倍标准偏差),对含~(220)Rn比~(222)Rn多的样品,结合使用Bunney曲线法进行~(220)Rn和~(222)Rn的分离是可能的。     

用222Rn测定室内通风率

在过去三年中,对北新泽西州一个独家住宅室内外~(222)Rn浓度进行了监测。用连续监测器收集地下室及户外每小时的~(222)Rn浓度数据,并建立了一个小实验房间作为地下室的延伸部份。原有房间的墙壁是混凝土浇注建成的,新的实验房间的墙壁则是由混凝土预制件建成,以提供更通畅的气孔和增加~(222)Rn对不同气象条件的响应时间。比起原有房间来,实验房间有较大的表面积/体积比和较薄的墙壁。大部份~(222)Rn来自土壤,室内~(222)Rn的主要来源是通过地下室土壤交界面的渗入。在估算~(222)Rn     

浙江部分地区室内222Rn和220Rn水平及剂量估算

Objective To investigate the concentrations of indoor radon (222Rn) and its daughter products as well as indoor thoron (220Rn) in selected houses in Yuhang district and Sanmen county,Zhejiang province,and estimate their annual effective doses to the population.Methods Solid state nuclear track detectors were used in selected dwellings in Yuhang district and Sanmen county,and the detectors were placed in bedrooms or living rooms.Without changing the ventilation habits of residents,These detectors were continuously placed from March to September in 2009.Results Indoor 222 Rn and 220Rn concentrations in low-rise buildings were the highest among all types of houses.The indoor concentration of 222 Rn had no relation with the building age (F = 0.53,P ＞ 0.05),but that of 220 Rn was dependent on the building age (F = 3.56,P ＜ 0.05).Moreover,the investigation demonstrated indoor 220 Rn concentrations in houses with no decoration were higher than in the houses decorated (t = 2.33,P ＜0.05).The average indoor concentrations of 222Rn and 220Rn in Yuhang district were 32.5 Bq/m3 and 314.3 Bq/m3,respectively,and the annual effective doses were 0.88 mSy and 0.42 mSv respectively.The average indoor concentrations of 222Rn and 220Rn in Sanmen county were 26.8 Bq/m3 and 399.5 Bq/m3,and the annual effective doses were 0.72 mSy and 0.53 mSv respectively.Conclusion The concentrations of indoor 222 Rn in some areas of Zhejiang province are at natural background level,and the concentrations of indoor 220Rn in rural areas are relatively higher.The total annual effective dose from 220Rn and its progeny was larger than that from 222Rn and its progeny by 50 percents.     

平凉地区居民住宅中~(222)Rn、~(220)Rn浓度的研究

环境中氡的危害已普遍被人们接受。这里提到的氡通常是指2 2 2 Ｒｎ ,虽然在估算2 2 2 Ｒｎ危害的同时人们已意识到2 2 0 Ｒｎ的危害 ,也给出了2 2 0 Ｒｎ剂量转换因子。但是由于2 2 0 Ｒｎ的半衰期很短 ,迁移距离不足 1ｍ ,加之测量和刻度有一定难度 ,过去对于环境和住宅中2 2 0 Ｒｎ的研究很少。1 991年日本进行了全国范围的氡水平调查 ,首先发现内墙为土木结构的日本传统式建筑物内2 2 0 Ｒｎ的浓度较高[1 ] 。1 993年在甘肃省陇东地区氡浓度调查中也发现了2 2 0 Ｒｎ对2 2 2 Ｒｎ测量干扰的问题[2 ] 。甘肃省陇东地区有相当数量的人口居…     

空气发光计数对用液体闪烁计数测定~(222)Rn的影响

本研究的目的是测量~(222)Rn及其子体产生的空气发光计数随闪烁液体积的变化及空气发光计数对用液体闪烁计数测定~(222)Rn的影响.~(222)Rn的空气样品在测量之前在杯中保持3.5小时,使子体~(218)Po、     

香港室内外~(222)Rn和~(220)Rn子体

人类受到的天然放射性照射中最大贡献来源于Rn衰变产物。在通风差的室内环境,由于蓄积导致Rn浓度的升高,吸入人肺部足以造成辐射危害。香港人大多生活在高层建筑中,由于香港炎热和潮湿的气候,密闭式空调已非罕见。为此,作者在香港大学校园内进行了小规模的调查,测量室内~(222)Rn和~(220)Rn水平。调查使用五段计数滤膜法。以已知流速,一定的采集时间,抽取已知体积的空气样,通过高效率的滤膜。滤膜在一定时间周期内使用ZnS闪烁探头计数,并假设放射性完全由~(222)Rn和~(220)Rn子体贡献。测定收集效率和探头计数效率。在采样时和计     

家庭用水对科罗拉多室内空气中~(222)Rn的贡献

在科罗拉多调查了28间房屋家庭用水对室内空气中~(222)Rn的贡献.在一些房屋中,家庭用水含~(222)Rn量较高,这可能是室内空气中~(222)Rn含量高的主要来源.方法:从家庭水井中采集水样,用液闪分析法测定~(222)Rn浓度,用α径迹探测器测定空气中~(222)Rn.探测器分别放在地下室、居室和浴室,每个采样点的户主填写调查表,内容包括:家庭人口、居住面积、房间高度和用水量.根据调查表中每周的平均用水量计算每天用水量.结果:水中~(222)Rn浓度是3.6kBq·m~(-3)～6.1M-Bq·m~(-3),地下室空气中为67Bq·m~(-3)～5.6kBq·m~(-3),居室是5.9～1300 Bq·m~(-3).在28间中,至少有19间     

甘肃陇东地区室内222Rn、220Rn浓度季节变化的调查分析

目的 研究我国传统住房室内222Rn、220Rn随季节变化的规律.方法 选择甘肃省陇东地区5种不同类型的传统建筑44间及普通砖瓦房5间.采用LD-P型222Rn-220Rn分辨累积探测器,按冬、春、夏、秋4个季节对室内222Rn、220Rn浓度进行测量.结果 室内222Rn浓度随季节变化而变化,不同种类房屋变化规律不同...     

低收入家庭中的~(222)Rn水平

作者报道了对美国全国及匹兹堡地区低收入(年收入低于15000美元)家庭中~(222)Rn浓度的调查结果.在1986年3月至1987年4月期间总共调查了32740个家庭,其中低收入家庭有808个.~(222)Rn浓度用扩散栅活性炭吸附探测器(DBCA)测量.匹兹堡地区的调查对象有三个来源:①那些自新闻媒介得知匹兹堡大学愿免费为送来食品印花认可购买卡(Food stamp anthorization-to-purchase card)副本的家庭测量~(222)Rn浓度消息后,主动送来这一证件副本的低收入家庭有101户;②通过随机选择     

建筑物内气载222Rn衰变产物的有效排除

室内天然~(222)Rn短寿命衰变产物(~(213)Po、~(214)Pb和~(214)Bi)的暴露是一个值得关注的公共卫生问题。这些衰变产物是公众电离辐射暴露的主要原因之一。为寻找减少吸入室内空气中~(222)Rn衰变产物的各种有效方法,应用稳定状态的~(218)Po、~(214)Pb和 ~(214)Bi的浓度和没有吸附在微粒上的核素浓度值,用现代工艺制作的肺模型在78m~3室内对空气处理前后的测量值进行比较。为了降低对射线敏感的支气管组织受照剂量,设想用净化空气的办法,如使空气对流,空气过滤和静电除尘等。这些办法虽然     

某温泉浴室中~(222)Rn及其子体浓度水平调查

人类天然辐射照射剂量的５０％来自氡及其子体，咸宁、蒲圻两处温泉已广泛用于治疗疾病、疗养和浴用。但温泉水中含有较高的放射性一直是人们关注的问题，影响两地旅游业和温泉水的开发利用。本文作者进行了调查，并对氡及其子体所致照射剂量进行了估算和评价。１方法本调...     

西班牙阿斯图里亚斯中部地区室内~（222）Rn浓度

西班牙阿斯图里亚斯中部地区室内２２２Ｒｎ浓度［英］／ＩｇｌｅｓｉａｓＪＭＰ…∥ＨｅａｌｔｈＰｈｙｓ．－１９９６，７０（５）．－６８９～６９４建筑物内２２２Ｒｎ的主要来源是地基土壤、建材及室外空气。当一个地区地壳内的２３８Ｕ浓度达到３６Ｂｑ／ｋｇ数量级...     

222Rn detection at the μBq/m3 range in nitrogen gas and a new Rn purification technique for liquid nitrogen

For the Borexino solar neutrino experiment a concentration line for ²²²Rn from a large volume of nitrogen gas has been constructed. It is based on cryo-adsorption in a charcoal trap of very low intrinsic ²²⁶Ra contamination. Consequently, the blank for activity from the daughter nuclide ²²²Rn is very low. ²²²Rn is recorded with proportional counters. This allows the detection of Rn at concentrations below the μBq/m³ level in gaseous nitrogen.The removal of radon from liquid nitrogen is achieved by direct adsorption in the liquid phase. ²²²Rn – measurements on evaporated nitrogen with and without previous purification are reported.     

磷矿及其生产厂附近地下水和地表水中~(226)Ra和~(222)Rn浓度的评价

磷矿中含有可观的放射性核素,由矿石中天然铀和钍衰变而来。美国磷矿开采中天然铀浓度在5.4～267PCi/g左右。1974年美国磷工业平常生产中所提取的~(226m)Ra 比开采铀工业提取的还多。为测定磷酸盐工厂附近地区地下水源中~(226)Ra和。~(222)Rn 的浓度和地面水中~(226)Ra 的浓度,从而确定饮用这一地区的水是否会造成~(226)Ra 和它的子体对健康的危害,因此对工厂周围地区搜集井水样品和工     

用累积法对中国部分城市室内外222Rn浓度的调查

目的：为了解环境氡的变化规律和对人体的影响，从１９８８年１１月至１９９３年３月，中日合作对我国人口密集的１０个城市的室内外２２２Ｒｎ浓度进行了现场调查。方法：使用日本名古屋大学研制的Ａｌｏｋａ，Ｃｓ－２０１Ｂ型静电累积２２２Ｒｎ探测器。该仪器采样２个月时，探测下限为０，４Ｂｑ·ｍ－３。结果：室外１０个城市年平均值为８．８Ｂｑ·Ｍ－３，其中武汉市为最高（１３．５Ｂｑ·ｍ－３·ａ－１），上海的崇明岛最低（３．３Ｂｑ·ｍ－３·ａ－１）。在西北风的季节里，台湾地区室外２２２Ｒｎ浓度的５０％由陆地气团所贡献。室内１０个城市年平均值为１９．５Ｂｑ·ｍ－３，其中贵阳市最高（３３．９Ｂｑ·ｍ－３·ａ－１），上海的崇明岛最低（９．０Ｂｑ·ｍ－３·ａ－１）。１０个城市由２２２Ｒｎ及其子体所致公众年平均当量剂量为０．６４ｍＳｖ·ａ－１，其中贵阳市最高（１．１２ｍＳｖ·ａ－１），南通市最低（０．３９ｍＳｖ·ａ－１）。结论：以上结果表明，所调查的１０个城市室内２２２Ｒｎ的平均浓度值低于世界均值，２２２Ｒｎ及子体所致居民的平均剂量也低于世界均值。     

Distribution of the 222Rn decay products from a 226Ra solution in a PTB ampoule – Implications for calibration

The spatial distribution of the activity in a flame-sealed PTB ampoule containing ²²⁶Ra solution, incompletely filling the ampoule, was studied by autoradiography and by taking well-collimated gamma-ray spectra in 23 sections of the ampoule. A complex activity profile was observed and used for the Monte Carlo simulation of the ampoule by the GESPECOR code. The computed values of the efficiency transfer factors are in agreement with the experimental data. As a byproduct, the radon partition ratio in the solution–air phases was obtained.     

Comparison of two direct LS methods for measuring 222Rn in drinking water using α/β liquid scintillation spectrometry

Direct liquid scintillation (LS) methods are widely used for surveying ²²²Rn in drinking water. Two direct methods are used that differ in sample composition. In a two-phase sample, water lies below a water-immiscible cocktail, while in a homogeneous sample water is mixed with an emulsifying cocktail. Although these methods were developed in the late 1970s, their performances have not been simultaneously tested. Here, the methods were compared in two ways: by preparing both types of sample similarly from ²²²Rn-bearing groundwater in one emulsifying and in three organic cocktails, and by calibrating the methods with a ²²⁶Ra standard according to their respective procedures. The samples were measured using α/β LS spectrometry. The standard deviations of parallel samples and the repeatability of the measurements were excellent for both methods, except two-phase ²²⁶Ra samples, whose efficiencies decreased slightly over time. This instability was due to interference from ²¹⁰Pb, ²¹⁰Bi and ²¹⁰Po, which accumulated in the ²²⁶Ra standard, and possibly also to the migration of ²¹⁴Pb and ²¹⁴Bi into the aqueous phase and deficient transfer of ²²²Rn from the water to the cocktail.     

α径迹法测定空气中的氡-222——用灯提高检测的灵敏度

用固体径迹探测器α径迹法测量空气中氡-222的浓度虽有简便、经济、可多点同时测定等优点,但在实际应用中还存在若干必须解决的问题。空气中~(222)Rn及其子体(~(218)Po、~(214)Po)所放出的α粒子在硝酸纤维素薄片探测器(以下简称薄片)的不同深度产生的径迹,随浸蚀而扩大,形成刻槽。为了求得~(222)Rn浓度与径迹密度的精确关系,必须严格规定浸蚀时间及