130Ce(EC+β+)衰变研究及其放射化学分离

利用兰州SFC加速的16O束轰击同位素118Sn ,由熔合蒸发 4n反应产生目标核13 0 Ce。为了消除本底干扰并指定13 0 Ce核 ,采用溶剂萃取法对He - jet带传输系统从靶室传输出来的反应产物进行了离线分离与纯化。将目标核13 0 Ce从大量的靶材料、反应产物及母核中分离出来 ,快速制成薄源后在铅室中进行γ单谱测量及X -γ、γ -γ符合测量。从化学分离后的产物中观察到了半衰期为 2 2 .9min的 10 8条γ射线 ,其中 10 7条是新发现的 ,该活性被指定为13 0 Ce。在此基础上 ,进一步研究这些γ线的级联关系 ,建立了缺中子同位素13 0 Ce较完整的 (EC + β+ )衰变纲图。为118Sn(16O ,4n) 13 0 Ce反应体系建立的放化分离流程的分离时间仅 10min ,化学产额大于70 %。化学分离除去 98%以上的核反应生成的13 0 La ,对其它杂质的去污完全满足13 0 Ce(EC + β+ )衰变研究的要求。     

放射化学分离裂变产物中^79Se的新流程

因加速器质谱法（ＡＭＳ）测定＾７９Ｓｅ半衰期的需要，建立了一个从裂变产物中放化分离＾７９Ｓｅ的新流程。流程以硝基苯萃取－二氧化硫沉淀为主要步骤，避免了经典的ＳｅＢｒ４蒸馏法带来的＾７９Ｂｒ对＾７９Ｓｅ的同量素污染。流程的化学回收率大于６０％，对所要分离的各种放射性核素的去污能力满足要求。采用液闪方法测量＾７９Ｓｅ的放射性活度，并对影响活度测量的各种因素进行了详细的研究。用本流程获得的＾７９Ｓｅ可成     

He—jet带传输及X—γ（t）符合测量装置和^153Er（EC＋β^＋）衰变新γ的测定

介绍了Ｈｅ－ｊｅｔ带传输及Ｘ－γ（ｔ）符合测量装置分离鉴别重缺中子远离核的原理、速度和效率、离线测试了其最佳工作条件；利用该装置在线测量了＾１９５，１９６Ｂｉ、＾１５２，１５４Ｅｒ和＾１５３Ｅｒ的（ＥＣ＋β＾＋）衰变。６条新γ射线被确定Ｅｒ。     

Kinetic study on ligand-exchange reaction between ethylenedicysteine (EC) and 99mTc-glucoheptonate (99mTc-GH)

A detailed kinetic study of ligand-exchange reaction between 99mTc-GH and EC was carried out. The rate constants (k) of ligand-exchange reaction at different EC concentrations and different pH values were calculated. The k values (L@mol-1@min-1) were 3.7×103, 4.1×103, 3.9×103 and 3.9×103 at EC concentrations (?mol@L-1) of 559.7, 279.9, 186.6 and 55.97, respectively, while k values were 3.7×103, 3.4×103, 1.9×103 and 3.1×102 when pH values were 10, 9, 8 and 7, respectively, and k had an increase of the order of magnitude from pH 7 to pH 8. It demonstrated that k of the ligand exchange reaction was pH dependent and pH value of the reaction solution must be equal to or little higher than 8 in order to make the labeling yield of 99mTc-EC higher than 90%.     

Kinetic study on Iigand-exchange reaction between ethylenedicysteine (EC) and ~(99m)Tc-glucoheptonate (~(99m)Tc-GH)

A detailed kinetic study of ligand-exchange reaction between 99mTc-GH and EC was carried out. The rate constants (k) of ligand-exchange reaction at different EC concentrations and different pH values were calculated. The k values (L · mol-1 · min-1) were 3.7 × 103, 4.1 × 103, 3.9 × 103 and 3.9 ×88 103 at EC concentrations (μmol · L-1) of 559.7, 279.9, 186.6 and 55.97, respectively, while k values were 3.7×103, 3.4×103, 1.9×103 and 3.1×88 102 when pH values were 10, 9, 8 and 7, respectively, and k had an increase of the order of magnitude from pH 7 to pH 8. It demonstrated that k of the ligand exchange reaction was pH dependent and pH value of the reaction solution must be equal to or little higher than 8 in order to make the labeling yield of 99mTc-EC higher than 90%.     

The ITER EC H&CD upper launcher: Structural design

Four ITER EC H&CD (Electron Cyclotron Heating and Current Drive) Upper Launchers will be installed in the ITER Tokamak to counteract plasma instabilities by injection of up to 20 MW of millimeter-wave power at 170 GHz. Each Launcher features a structural system which is equipped with eight beam lines in a Front-Steering arrangement. The Launcher development has reached the status of a preliminary design, since the corresponding review meeting was held in November 2009 at the ITER site in Cadarache. All design work is performed by several EU associations being contracted by Fusion for Energy (F4E). The structural design of the Upper Launcher consists of three sub-components: First of all the Blanket Shield Module (BSM), which fills the gap between the regular blankets. The BSM dissipates about 80% of the nuclear heating and envelopes the front mirrors of the mm-wave system. Further the Launcher Mainframe, which provides a rigid structure for precise and secure integration of the mm-wave system to guarantee reliable operation under all potential scenarios. Finally the internals, such as dedicated support structures for the mm-wave system, shielding elements and components for gas and coolant supply. The most challenging design aspects are proper dissipation of nuclear heating in zones of high heat flux, the mechanical integrity during plasma disruptions, the integration of sufficient shielding material and the precise alignment of the mm-wave system under tight space conditions. Furthermore the definition of efficient manufacturing routes with respect to tolerance compliance requires substantial investigation and, though the Launcher is designed for ITER lifetime, potential repair by adequate remote handling procedures must be considered. This paper presents the recent status of the preliminary structural design and outlines future design approaches with the main focus on manufacturing methods, remote handling capability of the sub-components and optimum integration of the internals to bring the EC Launcher towards the final design.     

The ITER EC H&CD upper launcher: Structural system

After approval of the preliminary design of the ITER EC H&CD Upper Launcher, ECHUL-CA, a consortium of several European research institutes, was founded to pool resources for approaching the final design. At the end of 2011 the consortium has signed a 2 years contract with F4E to go ahead with the work on the launcher. The contract deals with design work on both the port plug, forming the structural system, and the mm-wave-system, which injects the RF-power into the plasma. Within the period of this contract all components being part of the Tritium confinement, of which the closure plate, the support flange, the diamond windows and the waveguide feed-throughs are the most outstanding ones, will get the status of the final design.Important steps to be done for the structural system are the optimization of the mechanical behavior of the launcher, leading to minimum deflections of the port plug during plasma disruptions and optimum seismic resistance. To reduce the effect of halo currents it was decided to recess the first wall of 100 mm compared to the regular blanket tangent. This recess requires substantial changes of the cooling system and the thermo-hydraulic design of the launcher. Also the layout of the shielding arrangement and the integration of the mm-wave system need significant revision. Moreover manufacturing aspects and enhanced remote handling capability are taken into account.For the final design also quality aspects must be considered; thus the design is elaborated with respect to applicable codes and standards, material specifications, risk analyses and the RAMI (reliability, availability, maintainability and inspectability) analysis to guarantee maximum performance of the device.This paper outlines the present status of the structural system of the EC H&CD upper launcher and represents the most recent steps towards its final design.     

Near-barrier Fusion Evaporation and Fission of ~(28)Si+~(174)Yb and ~(32)S+~(170)Er

<正>Heavy-ion induced fusion-fission reactions at energies around the Coulomb barrier have attracted much attention~([1-2]),due to many degrees of freedom involved in the interaction processes.It has been experimentally proved that the coupled interactions of some intrinsic motions and relative motion play a significant role in the process that     

The ITER EC H&CD Upper Launcher: Transient mechanical analysis

Four Electron Cyclotron Heating and Current Drive (EC H&CD) Upper Launchers (UL) are foreseen for plasma stabilization purposes in ITER. The mission of the UL is to mitigate neoclassical tearing modes (NTM) and the sawtooth instability by localized heating and current drive with high precision and accuracy. Special attention is to be aimed to the structural design of the UL, because of highly restrictive space requirements. The ECH upper launcher has a length close to 6 m and the nominal gap to the neighbouring components is 20 mm. Electromagnetic perturbations could induce forces on the conductive materials and result in an excessive displacement of the portions that are located far from the fixation.During the last years, the design of the UL has been optimized by means of static simulations of the structure. The peak loads obtained by the electromagnetic simulation of the eddy currents induced during an upward Vertical Displacement Event (VDE) (considered as the worst case disruption scenario for the UL) were used. Static simulations are a fast tool for comparing different structure configurations and optimization of the UL design, but they do not provide a complete picture of the real situation, since they do not take into account for dynamic effects that could lead to larger displacements.In this paper, modal and transient analyses of the structure of the quasi-optical design (Preliminary Design Review status) of the upper launcher are presented. The results of transient and static analysis have been compared together and the Dynamic Amplification Factor (DAF) with respect to the transient loads have been assessed. The transient study and the modal analysis have shown that the EC upper launcher has a stiff structure with relatively high natural oscillation frequencies (compared to the duration of the VDE) and that the dynamic effects do not constitute a critical issue.     

双死时间方法测量电子俘获核素^54Mn的活度

双死时间方法是国际上９０年代提出的１种新的符合方法，与常规符合方法相比，它没有符合线路，计算简单，测量结果有比较好的精度。本工作首次将它用到液闪测量，取得了比较好的结果。     

离子色谱法（IC）测定高放废液中的Na^＋,K^＋离子

应用离子色谱法测定高放废液中的Na~+和K~+离子。先以EDTA螯合树脂预处理柱,除去废液中的过渡金属和重金属离子,再用高效低容量离子交换树脂单柱离子色谱法分析测定Na~+、K~+离子。当Na~+和K~+离子含量为μg/ml水平时,方法精度好于5%。     

Cross section of the reaction (n,d) + (n,np) + (n,pn) at even cadmium and tin isotopes for 14-MeV neutrons

Khar'kov State University. Translated from Atomnaya Énergiya, Vol. 75, No. 3, pp. 233-235, September, 1993.     

Study on Elastic Scattering of ~(21,22,23)Na+~(40) Ca

<正>Reaction with unstable nuclei is a frontier topic in the field of nuclear physics,in which one of the important problems is how the interaction potential of these nuclei is different from that of stable nuclei.By measuring the elastic scattering,the phenomenological optical potential can be extracted to understand the nuclear-nuclear interaction and its reaction mechanism in general.