放射性氙测量中的天然源γ谱仪校准技术

基于禁核试核查现场视察的需求,研制了用于放射性氙测量的模拟气体源,实现了¹³³Xe 81.0 keV γ射线的效率校准。放射源基质为聚苯乙烯泡沫颗粒,母体核素为²²⁶Ra,采用不锈钢外壳封装,同时采用碳纤维窗以减少射线的衰减。放射源研制完成后,对其进行气密性和均匀性检验。当放射源达到平衡后,测量²¹⁴Pb的特征X射线的探测效率,然后插值计算得到¹³³Xe 81.0 keV γ射线的探测效率。为检验校准结果的正确性,制作了一个基质和几何尺寸均与²²⁶Ra源相同的¹⁵⁵Eu放射源,并在相同测量条件进行了实验。结果表明,¹⁵⁵Eu 86.5 keV γ射线和²¹⁴Pb 87.3 keV X射线的探测效率之间的相对偏差小于1.0%。     

Natural radionuclides in milk from the vicinity of a former uranium mine

Natural radionuclides in milk from farms in the vicinity of a former uranium mine ?irovski vrh in Slovenia, from a farm on the reference location, in powdered milk purchased from Ljubljana shops and in milk intended for infant food, were determined. In the milk samples, ²³⁸U, ²³⁴U, ²²⁶Ra, ²¹⁰Pb and ²¹⁰Po were determined. After sample preparation, radiochemical separation and preparation of counting sources, ²³⁸U, ²³⁴U, ²²⁶Ra and ²¹⁰Po were measured by alpha spectrometric system equipped with passivated implanted planar silicon detectors (PIPS) and ²¹⁰Pb by a gas-flow proportional counter. Activity concentrations varied from 0.009 to 0.354 Bq/kg dry weight for ²³⁸U, 0.019-0.177 Bq/kg dry weight for ²³⁴U, 0.041-0.110 Bq/kg dry weight for ²²⁶Ra, 0.290-0.652 Bq/kg dry weight for ²¹⁰Pb and 0.055-0.611 Bq/kg dry weight for ²¹⁰Po. Assessed combined annual effective doses per unit of intake were from 8.7 to 13.0 μSv/year for adults and from 195 to 648 μSv/year for infants.     

Studies of Actinium (III) in Various Solutions, (I)

A solvent extraction method using a mixture of 0.1M thenoyltrifluoroacetone and 0.1M tributylphosphate in carbon tetrachloride has been developed for the separation and purification of ²²⁸Ac in ²²⁸Ra solutions. The ²²⁸Ra was first purified by a preliminary extraction cycle. The ²²⁸Ac which had accumulated int his ²²⁸Ra fraction after the purification was separated and purified by a second solvent extraction cycle. Since commercially available ²²⁸Ra solution very often contains ²²⁶Ra, the γ-radioactive decay products of the ²²⁶Ra have to be carefully removed. The ²²⁸Ac thus prepared was found to be pure enough for use as tracer.     

<Superscript>212</Superscript>Pb/<Superscript>212</Superscript>Bi Generator for nuclear medicine

A scheme for producing the α-emitters ²¹²Pb and ²¹²Bi, to be used in a promising method of diagnostics and therapy in oncology – radioimmunotherapy, is proposed. The technology is based on two generators operating in tandem: ²²⁸Th/²¹²Pb and ²¹²Pb/²¹²Bi. The first one is based on separation from an initial solution containing thorium isotopes and gaseous ²²⁰Rn, which secures the purity of the desired products ²¹²Pb and ²¹²Bi. For a ²²⁸Th/²¹²Pb model generator, the efficiency of ²²⁰Rn extraction from solution was ~60%. After conditioning, the ²¹²Pb solution from the ²²⁸Th/²¹²Pb generator was used to charge a column, which functioned as a ²¹²Pb/²¹²Bi generator, with a cation exchanger.     

Thorium partitioning in Greek industrial bauxite investigated by synchrotron radiation and laser-ablation techniques

Typical red-brown (Fe-rich) and high-quality white-grey (Fe-depleted) bauxite samples from active mines of the Parnassos-Ghiona area, central Greece, were investigated. According to XRF and ICP-MS analyses their actinide content, and particularly of Th, is relatively increased. Fe-depleted samples contain up to 62.75 ppm Th corresponding to 220 Bq/kg due to ²²⁸Ac (²³²Th-series), whereas Fe-rich samples are less Th-radioactive (up to 58.25 ppm Th, 180 Bq/kg due to ²²⁸Ac). Powder-XRD patterns showed that Th-enriched (Fe-depleted) bauxite consists mostly of diaspore (AlOOH polymorph), anatase and rutile (TiO₂ polymorphs). SEM-EDS indicated the presence of Ti-Fe-containing phases (e.g. ilmenite, FeTiO₃), chromite (Cr-spinel) and besides LREE-minerals (mostly bastnäsite/parisite-group) and zircon (ZrSiO₄) hosting a part of the bulk Th. The presence of Th in diaspore and in Ti-containing phases (not detected by SEM-EDS as in the case of REE-minerals and zircon) was investigated, into distinct pisoliths of Fe-depleted bauxite, using μ-XRF and μ-XAFS in the SUL-X beamline of the ANKA Synchrotron facility (KIT, Germany). XAFS spectra of Th salts and Th-containing reference materials were obtained as well. Accordingly it was revealed, for the first time in the literature, that Ti-phases, and particularly anatase, host significant amounts of Th. This novel conclusion was complementary supported by LA-ICP-MS analyses indicated an average of 73 ppm Th in anatase grains together with abundant Nb (3356 ppm), Ta (247 ppm) and U (33 ppm). The Th L_III-edge XAFS spectra as compared to reference materials, give also evidence that Th⁴⁺ may not replace Ti⁴⁺ in distorted [TiO₆] fundamental octahedral units of anatase and ilmenite lattice (CN = 6). The occupation of either extraframework sites of higher coordination (CN = 6.9 or even CN = 7.4), according to EXAFS signals evaluation, or of defected/vacant (**) sites is more probable. This is likely explained by the difficulty of Th⁴⁺ to replace directly Ti⁴⁺ in [6]-coordinated (octahedral) sites due to the large difference in the relevant ionic radii (0.940 and 0.605 Å respectively).     

我国膳食中~(90)Sr、~(137)Cs、~(226)Ra、~(228)Ra、~(210)Pb 和~(210)Po含量及其所致内照射剂量

作为1990年全国总膳食调查的放射性物质部分,本文报道了组成我国膳食的各类食品中~(90)Sr、~(137)Cs、~(226)Ra、~(228)Ra、~(210)Pb 和~(210)Po 含量的测定结果;按调查所得膳食组成和食品中核素含量,估算了我国居民(成年男子)当前这些核素经食入所致年摄入量和待积有效剂量当量。结果表明,每年食入所致总待积有效剂量当量约为0.24 mSv,贡献较大的食品是蔬菜、水产品和谷类,贡献较大的核素为~(210)Pb、~(210)Po 和~(228)Ra。这些结果更新了我国膳食中这些核素的资料,补充了来自饮水的数据。文中还讨论了我国膳食组成的地区差异及其对居民摄入量和所致内照射剂量的影响。     

珠江口、大鹏湾和大亚湾海域海水及沉积物中放射性核素水平

本文报道了珠江口、大鹏湾和大亚湾海域海水及沉积物中放射性核素水平。经2013年9月秋季航次和2014年4月冬季航次取样监测,珠江口、大鹏湾和大亚湾海域海水中²²⁶Ra、²³²Th、⁴⁰K和¹³⁷Cs的放射性活度浓度分别为12.8～42.6 Bq/m³(平均21.7±7.3 Bq/m³)、3.2～26.6 Bq/m³ (平均11.8±6.5 Bq/m³)、529.7～974.1 Bq/m³(平均820.6±120.0 Bq/m³)和0.5～3.8 Bq/m³ (平均2.3±1.0 Bq/m³);沉积物中²²⁶Ra、²³²Th、⁴⁰K和¹³⁷Cs的放射性活度浓度分别为16.9～35.0 Bq/kg (平均27.9±7.2 Bq/kg)、22.0～59.8 Bq/kg (平均36.5±11.1 Bq/kg)、326.2～621.0 Bq/kg(平均456.2±100.1 Bq/kg)和0.3～3.5 Bq/kg(平均1.5±0.7 Bq/kg);海水及沉积物中^110mAg的含量均低于检测限。珠江口、大鹏湾和大亚湾海域海水及沉积物中放射性核素水平与我国其它海域相当。     

Nuclear Data Sheets for A = 215

The evaluated spectroscopic data are presented for 12 known nuclides of mass 215 (Hg, Tl, Pb, Bi, Po, At, Rn, Fr, Ra, Ac, Th, Pa). For ²¹⁵Hg, ²¹⁵Tl, ²¹⁵Pb, and ²¹⁵Pa nuclei, no excited states are known. The decay characteristics of ²¹⁵Hg and ²¹⁵Tl are unknown. The decay scheme of ²¹⁵Pb is considered as incomplete. Ordering of γ cascades in the decay of 36.9–s isomer of ²¹⁵Bi and for high–spin states above 2251 keV in ²¹⁵Fr are not established. High–spin excitations, including several isomeric states, are well known in ²¹⁵Bi, ²¹⁵Po, ²¹⁵Rn, ²¹⁵Fr, ²¹⁵Ra, and ²¹⁵Ac. No particle–transfer reaction data are available for any of the A=215 nuclei.     

粤北铀矿山环境水中天然铀、天然钍及226Ra水平调查

2011年,分丰水期和枯水期2次对粤北3个铀矿山所在地区环境水体进行了天然铀、天然钍、226Ra等放射性核素水平的调查测量。饮用水(非受纳水体)采样点11个,样品22个;溪水(受纳水体)采样点10个,样品20个。调查结果表明,饮用水(山泉水)中天然铀、天然钍和226Ra的平均浓度分别为0.74μg/L、0.53μg/L和17.0 mBq/L;溪水中分别为23.4μg/L、0.43μg/L和25.0 mBq/L。     

Radiation dose estimation and mass attenuation coefficients of marble used in Turkey

In this study the natural radioactivity in marble samples used in Turkey was measured by means of gamma spectrometry. The results showed that the specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K ranged from 10 to 92 Bq kg⁻¹, from 4 to 122 Bq kg⁻¹ and from 28 to 676 Bq kg⁻¹, respectively. The radiological hazards in marble samples due to the natural radioactivity were inferred from calculations of radium equivalent activities (Ra_eq), indoor absorbed dose rate in air values, the annual effective dose and gamma and alpha indexes. These radiological parameters were evaluated and compared with the internationally recommended values. The measurements showed that marble samples used in Turkey have low level of natural radioactivity; therefore, the use of these types of marble in dwellings is safe for inhabitants. Mass attenuation coefficients (μ/ρ) were obtained both experimentally and theoretically for different marble samples produced in Turkey by using gamma-ray transmission method. Experimental values showed a good agreement with the theoretical values.     

新疆伊犁燃煤灰放射性核素水平与富集因子分析

为了探明新疆伊犁家用燃煤灰放射性核素比活度本底值,分析了新疆伊犁河谷各矿区的48个有效燃煤炉灰样。分析结果表明:燃煤灰238 U、232 Th、226 Ra和40 K比活度范围分别为11.5~682.0、7.5~88.7、11.4~926.0、LLD~372.0Bg/kg;比活度均值分别为104.4、37.6、126.7、101.7Bq/kg。计算得到41对燃煤与燃煤炉底灰放射性核素238 U、232 Th、226 Ra、40 K的富集因子为0.1~26.6、3.3~309.2、0.4~284.0和1.7~225.5,238 U、232 Th、226 Ra相对富集因子为0.01~19.97、0.06~77.9和0.02~54.5。研究表明,此次调查的家用燃煤灰放射性核素数据与其它地区和国家数据相比为最小,燃煤与家用燃煤灰的富集因子与文献报道的相似,根据联合国电离辐射效应委员会统计的全球煤及煤灰背景值资料,此次数据均在正常值范围内。     

Nuclear Data Sheets for A = 211

The evaluated spectroscopic data are presented for 11 known nuclides of mass 211 (Hg, Tl, Pb, Bi, Po, At, Rn, Fr, Ra, Ac, Th). The ²¹¹Pa nuclide is included here but its identification remains uncertain. For ²¹¹Hg, ²¹¹Tl, ²¹¹Ac and ²¹¹Th nuclei, only the ground–state information is available. Their decay characteristics are mostly unknown. ²¹¹Fr is suggested to decay partially through ε decay mode, but its decay scheme remains poorly known. While high–spin excitations, including several isomers, are well studied in ²¹¹Pb, ²¹¹Bi, ²¹¹Po, ²¹¹At, ²¹¹Rn and ²¹¹Fr, the particle–transfer data are available for only ²¹¹Po and ²¹¹Bi.This evaluation was carried out as part of joint IAEA–ICTP workshop for Nuclear Structure and Decay Data, organized and hosted by the IAEA, Vienna and ICTP, Trieste, August 6–17, 2012. This work supersedes previous A=211 evaluation (2004Br45) published by E. Browne which covered literature before January 2003.     

Analytical Models for Migration of Radionuclides in Geologic Sorbing Media

In safety evaluation of nuclear waste repository systems, the analysis on migration of radionuclides in geologic media is important. In previous analytical models called Band- Release, Step-Release and Impulse-Release for decay chains, nuclide-specific release rate and time-dependence of release rate can not be taken into consideration. In this paper, two new release models are proposed. In Preferential-Release model, both of nuclide-specific release rate and time-dependence of leach are taken into account. Exponential-Release model is a special case of Preferential-Release model, in which no preferentiality in leach is assumed. The obtained analytical solutions for these new models are applicable even to four or more member decay chains and are as simple as those for the previous models.

As an example of the application of the new models, the discharge rates of the four nuclides in the decay chain of ²³⁸Pu→²³⁴U→ ²³⁰Th→²³⁶Ra→ into a surface water body are calculated as a function of time after the start of leach and path length from the repository. By using the result, heavy hazard due to ²³⁸Pu at short distance and ²²⁶Ra at long distance are also discussed briefly.     

基于Fe(OH)3-CaCO3载带的水中228Ra的γ能谱分析方法

建立了一种基于Fe(OH)₃-CaCO₃载带的水中²²⁸Ra的γ能谱分析方法，适用于环境水中²²⁸Ra的分析。采用Fe(OH)₃-CaCO₃共沉淀法富集水中的²²⁸Ra，将富集后的²²⁸Ra采用Ba(Ra)SO₄共沉淀法进一步载带，¹³³Ba示踪法确定²²⁸Ra的全程回收率，使用高纯锗γ谱仪测量与²²⁸Ra达到放射性平衡的衰变子体²²⁸Ac的特征γ能量，从而获得²²⁸Ra的分析结果。通过对5 L水样的加标验证可知，²²⁸Ra回收率为81.8%~87.5%，加标水样测量结果与添加量的相对偏差为1.7%~5.3%，此方法的探测限为57.2 mBq/L。     

γ Spectrometry Analysis Method for 228Ra in Water Based on Fe(OH)3-CaCO3 Carrier

The γ spectrometry analysis method for ²²⁸Ra in water based on Fe(OH)₃-CaCO₃ carrier was developed, which is suitable for the analysis of 228Ra in environmental water. The enrichment method of ²²⁸Ra in water was carried out by Fe(OH)₃-CaCO₃ co-precipitation method. The enriched 228Ra was further loaded by Ba(Ra)SO₄ co-precipitation method, and ²²⁸Ra was determined by ¹³³Ba tracer method. The full recovery rate was measured using high-purity Ge γ spectrometer to measure the characteristic γ energy of the decaying daughter ²²⁸Ac, which reached the radioactive equilibrium with ²²⁸Ra, thereby obtaining the analysis result of 228Ra. Through the calibration of 5 L water sample, it is known that the recovery rate of 228Ra is in the range of 81.8%-87.5%. The relative deviation of the water sample measurement is 1.7%-5.3%, and the detection limit of this method is 57.2 mBq/L.     

燃煤电厂对环境放射性水平的贡献

报道了我国主要原煤及粉煤灰中的天然放射性核素水平，分析了煤在燃烧过程中的除尘灰和飞灰对原煤中的放射性核素浓缩倍数，并与国外进行比较，同时将上海２５０ＭＷ燃煤电厂排放的放射性水平与国外核电站排放的放射性水平进行了比较。     

SRM4350B河泥标准参考物质的比对测量结果分析

本文报道了国内在1982年用γ谱仪对环境放射性样品中多种核素进行同时分析的比对结果。各比对实验室分析了 NBS 的 SRM4350B 河泥标准参考物质中的十种放射性核素(~(60)Co,~(137)Cs,~(152)Eu,~(154)Eu,~(226)Ra,~(40)K,~(232)Th,~(235)U,~(238)U,~(228)Th)。文中对测量结果做了初步分析。     

γ谱无源效率刻度法测量IAEA国际比对样品

利用γ谱无源效率刻度法对IAEA在2010年-2012年间提供的6个水样、3个土壤样和1个生物灰中的~(241)Am、~(133)Ba、~(60)Co、~(134)Cs、~(137)Cs、~(152)Eu、~(228)Ac、~(40)K、~(208)Tl、~(226)Ra、~(214)Bi、~(212)Pb、~(214)Pb、~(238)U等核素进行了活度浓度分析。测试结果与IAEA的参考值相比,报送的41个数据总体接受率为100%。通过比对结果分析,验证了γ谱无源效率刻度方法的实用性和可靠性,为该方法在环境辐射监测中的广泛应用提供了依据。     

Nuclear Data Sheets for A = 228

The experimental data for nuclei in the mass chain A = 228 have been examined, and the results summarized. Where possible, the results are presented in pictorial form. The text contains tables of adopted levels and properties, tables of radiations, comments which point out deficiencies or inconsistencies in the data, and a reference list.For those cases where only tentative or partial decay schemes are given, the reader is encouraged to contact the compiler for more specific detail.Structure information is relatively sparse except for the ²²⁸Th nucleus. Except where noted, Q—values have been adopted from 74WaBG. Data for the decay of the ground states of the A = 232 isotopes have been taken from 70Sc37 since there has been little modification except for the half—life of ²³²Pu (see 73Ja06) and alpha decay of ²³²U (see 71So15 and 72Go33). Data on the alpha decay of A = 228 nuclei have been taken from the compilation for A = 224 (this issue) by Y. A. Ellis. In the drawings, transition intensities per 100 decays of the parent are given.The compilation has been prepared by computer from data sets entered by the compilers into the Evaluated Nuclear Structure Data File (ENSDF). Corrections or additions to the content of this compilation should be addressed to the compiler for inclusion in the ENSDF.     

Measurements of natural radionuclides in soil samples from Upper Egypt

This paper presents the results of natural radioactivity measured for the soil of Qena using gamma-ray spectrometry at ZSR, Hanover University, Germany. Soil samples of radioactive concentrations of ^238U-series （^234Th, ^214pb, and ^214Bi）, 232Th-series （^228Ac, ^212pb, and ^208Tl） and ^40K were analyzed. Three objectives were set： （1） activity levels by surface soft sampling at 0-30 cm depth, （2） dose rates of gamma radiation, radium equivalent, index hazard, and effective dose, and （3） ambient dose rates.