渭河陕西段河流沉积物天然放射性研究

本文对渭河陕西段河流沉积物放射性水平进行了调查.用NaI(Tl)低本底γ谱仪测量了渭河陕西不同段沉积物样品天然放射性核素活度,分析了不同段天然放射性核素的含量特征及其辐射危害.结果表明,渭河陕西段河流沉积物中天然放射性核素水平正常,使用渭河陕西段河流沉积物(河砂)作为建筑材料时,建材中放射性比活度不存在超标问题.     

高放废液总β放射性活度测量

方法采用塑料闪烁晶体β低本底测量装置直接测定了高放废液样品40 keV以上β射线的总β放射性活度。装置的β效率曲线采用与被测样品相同质量厚度、不同β能量的一系列标准源刻度。样品测量的β放射性对装置的总β效率是根据各个样品的放射性核素组成、各核素β射线能量对应于β效率曲线值以及各核素β放射性活度占样品总β放射性活度的比例加权平均计算求得。在测定样品各核素β放射性活度占总β放射性活度的比例时,方法对具有γ衰变的核素采用直接γ能谱法;对纯β衰变核~(90)Sr-~(90)Y,采用了半衰期近似法;对纯β衰变核~(147)Pm,采用了表观冷却时间近似替代法对高放废液样品测量的不确定度约为±15%。测量结果与化学分离各核素测得的结果在误差范围内符合。     

85例正常人发中~(210)Po含量分析

放射性~(210)Po是人们受到天然放射性本底辐射的一种重要α核素,特别是在铀矿山,~(210)Po是使工作人员受到内照射的重要核素之一。由于~(210)Po的生物危害很大,其进入人体内主要途径是胃肠道及呼吸系统。因此,六十年代开始愈来愈引起放射医学研究工作者的重视。近年来,有关~(210)Po在人体内各组织     

湘江衡阳段天然放射性核素水平调查

为了掌握湘江衡阳段天然放射性核素水平及来源,分别于枯水期(11—12月)、丰水期(4—6月),对湘江衡阳段和该段4条主要支流(舂陵水、蒸水、耒水、洣水)水中的U、Th、²²⁶Ra、⁴⁰K、²¹⁰Po、²¹⁰Pb 6种天然放射性元素/核素进行了调查。测量结果表明:与长江水系及洞庭湖水系历年放射性水平均值相比,湘江衡阳段6种天然放射性核素中²²⁶Ra、²¹⁰Po、²¹⁰Pb明显偏高,说明湘江衡阳段的确受到了放射性污染。4条支流中,舂陵水及蒸水放射性核素浓度异常,明显高于汇入前后的湘江水体的放射性活度浓度。因此,这两条支流区域可能存在放射性污染源头,应对这两条支流区域进行更深入的取样调查,找出其污染源。     

^139Ce放射性标准溶液活度测量比对

~(139)Ce属于电子俘获核素,衰变纲图比较明确,γ射线能量为165.864keV,比较适合于γ谱仪重要能区的效率刻度。该核素的活度测量比对在放射性计量工作中有着十分重要的意义。 由国防科工委放射性计量一级站提供的~(139)Ce比对溶液经过高纯错γ谱仪进行放射性杂质检查,     

某矿山天然放射性核素的调查

对某矿山工作场所和生活区分别进行了样品采集,并使用ORTEC公司生产的16000道HPGeγ能谱仪进行了测量。结果表明,该矿山工作场所天然放射性核素的比活度大多高于生活区,其中危害最大的为尾矿坝;某些生活区天然放射性核素的比活度比对照点和国家均值要高,但多数都在国家均值范围内,最高值出现在3号生活区的农田土样中,其天然放射性核素的比活度分别为:a(226Ra)——750.4Bq/kg、a(232Th)——91.5Bq/kg、a(40K)——1202Bq/kg。     

高放废液中钚,镅含量及总α放射性活度的测定

采用经计数堆积、分析器阈值、源自吸收、源底衬对α粒子的反散射及系统死时间等计数效率影响校正后的栅网电离室,测定样品的总α放射性活度;使用Si(Au)半导体α谱仪测定钚、镅等核素的α放射性的比例;借助核燃料钚同位素的丰度及一些核数据,可获得高放废液样品中钚、镅等核素的含量。对于一般高放废液中的总α放射性、钚及镅含量测定的不确定度为±3%。     

用硕大草藨作为河口放射性污染指示物的初步研究

以硕大藨草为材料,采用多核素示踪法研究了该海草作为河口区放射性污染指示物的可能性。结果表明,硕大藨草对~(137)Cs、~(65)Zn、~(60)Co、~(59)Fe、~(54)Mn等核素的积累与核素浓度的相关系数均>0.71;硕大藨草浓集上述核素进入第8天就趋于动态平衡;土壤中的核素经一个月洗脱后,植物体内核素的残留量最低仍达 9.2％,处于可检测范围内。测定了地上茎从海水中及根部从土壤中吸收的核素分别在根部、地下茎、地上茎的浓集系数,结果表明前者的吸收能力大于后者。再通过浓集系数公式的换算,可以同时反映海水、土壤两方面放射性的污染程度。     

放射性滑膜切除术

放射性滑膜切除术是一种治疗多种慢性关节炎的有效方法,与手术、化学药物滑膜切除术相比有明显优势。本文重点介绍放射性滑膜切除术的作用原理、适应证、药物选择、操作方法、临床应用情况及并发症与预后等内容。     

85例正常人发中~(210)Po含量分析

放射性~(210)Po是人们受到天然放射性本底辐射的一种重要α核素,特别是在铀矿山,~(210)Po是使工作人员受到内照射的重要核素之一。 近年来,有关~(210)Po在人体内各组织器官中含量测定,国内外已作了大量工作,人发中~(210)Po含量,不少学者认为可作人体内~(210)Po含量的指示器。     

Radiation Monitoring-An Instrumentation System for Control of Radiation Hazards

The requirements for radiation monitoring from an integrated instrumentation system aspect are developed with emphasis on the detection and control of radiation hazards. General treatment is given to the problems and equipment involved in operational or process monitoring, site monitoring, effluent monitoring and area or personnel monitoring. The types of radiation that are encountered in a nuclear plant and the units of measurement that are used are discussed. A review of the types of monitoring equipment that are presently available to make plant and personnel measurements and their sensitivity and reliability as related to meeting accepted standards for plant personnel and general public protection is given. A typical radiation monitoring system and the basis for the design are described. A brief summary of the status of development of solid state monitors is included.     

Radiation level changes at RAM package surfaces

Abstract

This paper explores design considerations required to meet the regulations that limit radiation level variations at external surfaces of radioactive material (RAM) packages. The radiation level requirements at package surfaces (e.g. TS-R-1 paragraphs 531 and 646) not only invoke maximum radiation levels, but also strict limits on the allowable increase in the radiation level during transport. This paper explores the regulatory requirements by quantifying the amount of near surface movement and/or payload shifting that results in a 20% increase in the radiation level at the package surface. Typical IP-2, IP-3, type A and type B packaging and source geometries are illustrated. Variations in surface radiation levels are typically the result of changes in the geometry of the surface due to an impact, puncture or crush event, or shifting and settling of radioactive contents.     

Characteristics of coherent diffraction terahertz radiation at SDUV-FEL

1IntroductionTheterahertzradiationregimeoftheelectro-magneticwavespectrumisnotwellcoveredbyin-tensesourcesexceptforfewFELfacilities.Abright-nessfarexceedingthatfromablackbodyorsynchro-tronradiationsourcecanbeprovidedbyutilizingfemtosecondelectronbunches.Itcanbeusedforbasicandappliedresearchinmanyfields,suchasmaterialscience,high-Tcmaterials,polymerdynamicsandstructure,biologicalmolecules,phononandsurfacephysics,metrologystandards,etc.[1]Coherentdiffractionradiationisgeneratedbyrelativisticfe…     

Bias factors for radiation creep, growth and swelling

Central to the present concepts of the origin of the radiation-induced creep, growth and swelling phenomena is the relative interaction of interstitials and vacancies with various sinks. Radiation-induced climb of dislocations, which figures in many theories of radiation creep and growth, requires the absorption of an excess of either vacancies or interstitials. On the other hand, radiation swelling requires the absorption of an excess of vacancies to effect void growth. These relative preferences are normally expressed in theoretical models by certain bias factors, or capture efficiencies, usually assumed to be constant. Several attempts have been made to estimate their magnitude theoretically but all are seen to involve errors or physically unrealistic assumptions. We present here a unified treatment in which these various bias factors are estimated in a self-consistent model which incorporates, for the first time, all the essential physics, i.e., defect production, interactions of both vacancies and interstitials with sinks and the presence of two types of sinks. We present quantitative evaluations for the SIPA creep model and for radiation swelling, and compare with previous estimates of these phenomena.     

Prospects and challenges in application of gamma, electron and ion beams in processing of nanomaterials

Application of radiation techniques for nanotechnology has been known for years. X-ray, electron beam and ion beam lithography are good examples of applications. By using electron beams, ion beams and X-rays structures as small as 10 nm can be produced. Ion track membranes with track diameters from 10 nm to 100 nm are used as such or as templates for electroplating of nanowires of metal, semiconductor and magnetic materials. In the near future X-rays, focused ion beams and electron beams will be used for nanolithography and 3D fabrication; heavy ion beams on the other hand can be useful for fabrication of nanopores and nanowires. The use of radiation has proved to be an essential technique in the fabrication of nanostructures with high resolution as the radiation beams can be focused into few nanometer scales or less. Three groups of products could be considered to be fabricated by radiation techniques: nanoparticles, nanogels and nanocomposites. These and other possible fields of radiation processing applications in nanotechnology are discussed in the paper.     

某核电站放射工作人员外周血淋巴细胞微核检测结果分析

对2021年在本院体检的某核电站858名放射工作人员外周血淋巴细胞微核检测结果进行了分析。结果表明,放射工作人员的微核细胞率为4.57‰,微核率为4.89‰;不同年龄段放射工作人员的微核细胞率、微核率差异显著,且随年龄增长呈递增趋势;女性放射工作人员的微核细胞率、微核率均高于男性,但差异无统计学意义;不同放射工龄人员的...     

Multiquadric散乱数据插值方法在γ辐射场可视化中的应用初探

探究γ辐射场分布及其变化规律对于核设施的状态监控以及核辐射的防护研究具有重要意义。获取γ辐射场的空间分布需要解决利用少量、离散且分布不规则的实验数据重构整个辐射场的难题。本文首次将Multiquadric径向基函数散乱数据插值方法应用于γ辐射场的重构,并实现了γ辐射场模拟数据重构及可视化。对于具有轴对称性的γ辐射场,在采样数据点个数相同的条件下,与数据处理软件MATLAB中自带的Spline方法得到的插值结果相比,Multiquadric方法插值结果的平均相对误差仅为前者的9.47%;对于转动π/2对称的γ辐射场,提出了一种采样数据优化方案,重构结果的平均相对误差相较于未优化采样数据的结果降低了约64.51%。     

Nuclear Radiation Sources on Board Oluterpianet Spacecraft

Radioisotope thermal electric generators (RTG's) and radiation heater units (RHU's) are presently being used or considered for sources of electrical power and heat for the Apollo, Pioneer and Viking Projects. Both RTG's and RHU's have considerable merit if proper precautions are taken to compensate for overall system response to the nuclear radiation sources. This paper summarizes the nuclear characteristics of plutonium fuel which gives rise to the radiation from both RTG's and RHU's, gives Monte Carlo estimates of the neutron and gamma isodose profiles from a 2200 watt (th) HELIPAK** thermoelectric generator and concludes with a presentation summary of shield thicknesses required for several sensitive radiation experiments due to combined RTG-RHU fields. This study is a part of a continuing program of analysis at the Jet Propulsion Laboratory on the evaluation of RTG radiation fields on an outerplanet spacecraft.     

Quantitative radiometric measurement of radioactive ores in the natural occurrence

The measurement of gamma radiation of radioactive ores in the natural deposit — directly in the face of a mine working or in a bore hole-permits determination of the radioactive element content in ores without collection of test samples and without chemical analyses.The accuracy of quantitative measurement by gamma rays depends to a considerable degree on correct interpretation of the spectral content of the gamma radiation measured. The gamma-ray spectra of radioactive ores is determined by the process of radiation dispersion and depends on the content of the ore. The intensity of gamma radiation registered by an ore seam depends on the cathode malarial of the counter (tungsten, copper, graphite) as a consequence of the difference in spectral sensitivity of various counters. The relationship of gamma — radiation intensity during measurement with a Geiger counter with various cathodes permits one to characterize the spectral composition of the ore's gamma radiation.In order to express the results in general units, microroentgens per hour, the radiometers are calibrated with an exact standard, but the calibration method does not exclude the radiometer reading dependence on the spectral sensitivity of the counters.In this article are determined the important conversion coefficients connecting gamma-radiation intensity with the content of radioactive elements in ore (see the table) during measurements on the ore seam surface or in borings. During measurements in borings the reverse dissemination of gamma rays having low energy is of great importance.By use of these coefficients calculations of the radioactive element content in ore from counter readings are carried out.