建筑材料放射性检测的国际惯例

建筑物，无论是民用建筑，还是工业建筑，所用建筑材料(建筑主体材料、装饰材料)都不同程度地含有天然放射性物质。因此，关注各种建筑材料的放射性是人类生存、发展的必然。我国是WTO成员国的一员，建筑材料的放射性检测方法，包括建筑材料中核素限量、危害评估体系等理应按国际标准进行检测，使用国际上惯用的技术规则，还应与国际上惯用的建筑材料放射性核素限量及危害评估体系保持同步。     

中子注量探测器在快堆结构材料辐照损伤的应用研究

为评估快堆结构材料的辐照损伤，本文提出了一套快堆结构材料辐照损伤评价方法。根据快堆能谱特点设计中子注量探测器辐照方案，分析探测片特性和反应道截面，选取7种快中子注量探测器。同时采用迭代法在Labview平台中开发了解谱程序。基于俄罗斯碳化硼组件辐照实验数据进行解谱，并结合Lindhard-Robinson模型组件包壳原子平均离位（dpa）计算，同时与SPECTER计算值进行对比。结果表明，本文采取的实验方法得到的dpa与SPECTER计算值偏差在6%以内，符合较好。本文建立了一套完善的快堆结构材料辐照损伤评价体系，对结构材料的辐照损伤监测具有重要意义。     

气态放射性碘捕集方法研究进展

碘的捕集是对气态放射性碘的污染进行监测和治理的有效手段。本文概述了不同种类捕集材料的性能，对几种捕集方法作了比较和初步评估。活性炭浸渍炭常用于捕集气态元素碘和有机碘，但易受温度，湿度，气流速度等条件的影响，ＴＴＦ具有更优良的捕集性能。但价格昂贵；活性炭纤维作为多功能新型高效吸附材料，可能成为活性炭的换代产品。     

用蒙特卡洛方法计算砷化镓中的正电子迁移率

用计算机模拟的方法获得正电子在半导体材料的迁移率，讨论了正电子有效质量，杂质浓度和温度对正电子迁移率的影响。     

聚变α粒子对材料辐照损伤瞬时行为的研究

研究聚变α粒子对第一壁材料辐照损伤随时间的发展与变化，用基于时间序列两体碰撞近似的计算机模拟程序研究数＋ｋｅＶ α粒子对无定形铁材料的辐照损伤，计算了α粒子辐照引起的材料中空位和能量沉积分布及α粒子本身的沉积随时间的演化，还对用时间序列和速度序列两类级联碰撞模拟方法计算的结果作了比较。     

不同材料硬X射线屏蔽性能研究

以X射线荧光单能谱对金属靶材料的二次激发特征X射线作为测试光源,利用高纯锗探测器获取系列能点的实验数据,获得不同材料20～100 keV能谱范围内多能点的X射线透过率测量数据,研究了不同材料X射线屏蔽性能.理论计算的屏蔽效能与基于透过率实验测量的评估结果符合较好,该方法能较好评估材料的屏蔽效能,研究结果为屏蔽材料设计提...     

氢和其它轻元素的同时分析

准确测定材料中的成分及杂质的含量和其深度分布在新材料的研制中有重要作用。近年来，在新材料的研制和改性中经常用各种方法加入不同量的氢成分来改变材料的各种性能。由于卢瑟福背散射(RBS)不能测量H，人们通常用RBS测其它元素，再用α束弹性反冲法测H。两次测量存在截面归一和样品两次受照带来的辐射损伤问题。     

反应堆用石墨材料的氧化

在反应堆运行过程中，冷却剂中含有的氧化性气体杂质以及可能发生的进水事故和进气事故将导致石墨氧化，进而影响反应堆的正常运行和安全。文章主要对近期有关反应堆用石墨的氧化机理、氧化对石墨性能的影响、事故工况下的安全评估以及预防石墨氧化的措施等进行综述，并在此基础上指出，在辐照和氧化共同作用下的石墨材料性能变化是今后有关反应堆石墨研究的一个主要方面。     

离子轰击模拟中子辐照在核材料研究中的应用

简要综述了离子轰击模拟中子辐照对材料，尤其是对堆用Ｚｒ合金的结构和性能影响的相关性，方法特点和研究。讨论了离子品种，能量，辐照剂量，束流密度和温度等实验参量的选择及其对材料组织，结构，力学和耐腐蚀性能等的影响。离子轰击模拟堆内中子辐照研究核材料是１种具有成熟理论体系，高效，安全和经济的好方法。     

α能谱法测定Pu材料中^241Am／Puα活度比

文章介绍用α能谱法测定Ｐｕ材料中＾２４１Ａｍ／Ｐｕα活度比的原理、方法及结果，该测定结果与用ＮａＩ（ＴＩ）γ能谱法测定的结果相一致。     

Effect of the gas mixing technique on the production efficiency of ion beams extracted from an electron cyclotron resonance ion source

In this work the effect of gas mixing on the production efficiency of ion beams extracted from an ECR ion source has been studied with the JYFL 6.4 GHz electron cyclotron resonance ion source (ECRIS). It was found that the gas mixing affects strongly the confinement of ions in the plasma of the ECRIS. The information obtained can be used to minimize the consumption of expensive materials or isotopes and to reduce contamination of the plasma chamber. It was observed that the carbon contamination, which is built up when the MIVOC method is used could be decreased with the aid of the gas mixing technique. The best mixing gas for this purpose was found to be oxygen.     

MC法模拟地层元素测井仪优化中子屏蔽体

利用MC法模拟了D-T中子源发出的粒子通过地层元素测井仪内部屏蔽体结构的过程,获得了不同粒子通过不同材料的屏蔽体后能量和核反应截面的分布,从而得出不同材料在不同厚度下的粒子屏蔽效果。模拟结果表明:采用17 cm厚的三层复合屏蔽体结构,所用材料第一层为10 cm厚的钨镍合金,第二层为5 cm厚含20%碳化硼的聚乙烯,第三层为2 cm厚的铅。三层结构对中子的屏蔽率达到98.47%,对γ光子的屏蔽率达到97.68%。可有效降低仪器内部元素干扰,提高分辨率与精确度。     

Low-energy atomic displacement model of SRIM simulations

Radiation-induced atomic displacement damage is a pressing issue for materials.The present work inves-tigates the number of atomic displacements using the Pri-mary Knock-on Atom(PKA)energy EPKA and threshold displacement energy Ed as two major parameters via low-energy SRIM Binary Collision Approximation(BCA)full cascade simulations.It is found that the number of atomic displacements cannot be uniquely determined by EPKA/Ed or ED/Ed(ED refers to the damage energy)when the energy is comparable with Ed.The effective energy ED,eff pro-posed in the present work allows to describing the number of atomic displacements for most presently studied mona-tomic materials by the unique variable ED,eff/Ed.Never-theless,it is noteworthy that the BCA simulation damage energy depends on Ed,whereas the currently used analyt-ical method is independent of Ed.A more accurate ana-lytical damage energy function should be determined by including the dependence on Ed.     

Synthesis of polymeric micro- and nanostructural materials for application in non-linear optics

The present paper describes a new approach developed for the preparation of micro- and nanostructural materials on the basis of polymeric compositions used as a matrix in non-linear optics. This approach consists in filling the pores of poly(ethylene terephthalate) track membranes (PET TM) from polymeric compositions using an impregnation method. It is shown that depending on the concentration of polymeric compositions in the solution it is possible to form a variety of micro- and nanostructural materials (tubules and wires as well as composite membranes) with a wide spectrum of characteristics. The developed method of producing micro- and nanostructural materials provides a possible way for creating polymeric objects with non-linear optic properties which can be used to design electronic micro- and nanodevices and to obtain chemical and optical sensors.     

电子束辐照对医用一次性防护服材料断裂强力的影响

消毒灭菌是医用一次性防护服（简称医用防护服）生产过程中的重要环节,相比传统环氧乙烷灭菌,辐照灭菌更快速高效。由于医用防护服的防护性能有严格的标准要求,其材料的辐照效应具有重要研究意义。采用电子束加速器分别对聚丙烯（PP）、聚酯纤维（PET）、特卫强（Tyvek）3种材料的医用防护服样品进行不同吸收剂量的辐照处理,并进行不同时间的老化试验。针对GB 19082-2009中与辐照效应相关的主要性能指标进行测试。结果表明,50 kGy以下吸收剂量的电子束辐照对上述3种材料医用防护服的抗渗水性、抗合成血液穿透性、过滤效率等性能影响较小,但对PP和Tyvek材料的医用防护服断裂强力影响较大。通过双因素方差分析研究辐照和老化两种因素对上述3种材料医用防护服断裂强力影响的显著性。结果表明,吸收剂量和老化时间分别有不同的影响,其中吸收剂量对PP材料医用防护服样品断裂强力影响最显著。经验证,提升PP材料医用防护服的初始断裂强力,可使其辐照后性能满足标准。     

Principles for Finding Matrices for Immobilizing High-Level Wastes

The principles for selecting matrices for immobilizing high-level wastes are examined. It is concluded that actinides should be separated and embeeded in the matrix separately from fission products. The minimum significant specific activity, regulated by NRB-99, cannot be used to estimate the storage time. It is suggested that such values be established as a function of the leach rate of radionuclides and matrix materials from matrices. For this, a standard leaching method using pulverized materials must be specified. Two criteria are proposed for comparing matrix materials.     

Development of Fitting Methods Using Geometric Progression Formulae of Gamma-ray Buildup Factors

The gamma ray buildup factors are represented by an approximation method to speed up calculation using the point attenuation kernel method. The fitting parameters obtained by the GP formula and Taylor's formula are compiled in ANSI/ANS 6.4.3, available without any limitation. The GP formula featured high accuracy but required a high-level fitting technique. Thus the GP formula was divided into a curved line and a part representing the base values and used to develop the a fitting method and X_k fitting method. As a result, this methodology showed that (1) when the fitting ranges were identical, there was no change in standard deviation when the unit penetration depth was varied; (2) even with fitting up to 300 mfp, the average standard deviation of 26 materials was 2.9% and acceptable GP parameters were extracted; (3) when the same end points of the fitting were selected and the starting points of fitting were identical with the unit penetration depth, the deviation became smaller with increasing unit penetration depth; and (4) even with the deviation adjusted to the positive side from 0.5 mfp to 300 mfp, the average standard deviation of 26 materials was 5.6%, which was an acceptable value. However, the GP parameters obtained by this methodology cannot be used for direct interpolation using gamma ray energy or materials.     

Radiation dosimetry using three-dimensional optical random access memories

Three-dimensional optical random access memories (3D ORAMs) are a new generation of high-density data storage devices. Binary information is stored and retrieved via a light induced reversible transformation of an ensemble of bistable photochromic molecules embedded in a polymer matrix. This paper describes the application of 3D ORAM materials to radiation dosimetry. It is shown both theoretically and experimentally, that ionizing radiation in the form of heavy charged particles is capable of changing the information originally stored on the ORAM material. The magnitude and spatial distribution of these changes are used as a measure of the absorbed dose, particle type and energy. The effects of exposure on 3D ORAM materials have been investigated for a variety of particle types and energies, including protons, alpha particles and 12C ions. The exposed materials are observed to fluoresce when exposed to laser light. The intensity and the depth of the fluorescence is dependent on the type and energy of the particle to which the materials were exposed. It is shown that these effects can be modeled using Monte Carlo calculations. The model provides a better understanding of the properties of these materials. which should prove useful for developing systems for charged particle and neutron dosimetry/detector applications.     

Calculation of radiation fields in VVER shielding using approximations supporting local balance of materials mass and fission-source neutrons

The possibility of using approximations of geometry, which support the balance of materials mass on each spatial cell of a grid covering the computational region, to calculate radiation fields in VVER shielding by introducing additional mixtures of materials for cells where several initial materials are present is analyzed. The methods of combinatorial geometry, which are implemented in the MCU computer program for solving transfer equations by the Monte Carlo method, are used to specify the 3-D geometry of the shielding and a fuel-element and (or) fuel assembly fission source and the method of ray tracing is used to convert the combinatorial specification into a grid specification. A numerical experiment in which the VVER-1500 radiation shielding is calculated showed that the conservation of the materials mass/number of source neutrons in the grid cells during the conversion ensures rapid convergence of the results when the density of the spatial grid increases. Good agreement is attained between MCU Monte Carlo and KATRIN S_n calculations of VVER-1000 shielding. __________ Translated from Atomnaya énergiya, Vol. 104, No. 6, pp. 328–333, June, 2008.