800MeV质子入射^160、^27Al、^56Fe、^112Cd、^184W与^208Pb靶散裂反应机制

采用改进的量子分子动力学模型（ImQMD05）加统计衰变模型（SDM）来研究800MeV质子入射的散裂反应。采用不同的平均场，研究有效相互作用对散裂反应机制的影响，并给出工程应用上关心的出射中子的双微分截面。     

能量到GeV的质子入射铅靶的散裂产物分布研究(英文)

由中高能质子入射靶引起的散裂碎片的分布关系到散裂靶经长期辐照后的放射性废物的累积。在量子分子动力学模型(QMD)中考虑剩余核的裂变过程(FISSION),利用QMD FISSION模型研究了322,660,759 MeV的质子入射铅靶的散裂产物的分布。计算结果很好地再现了实验测量值。     

Estimate of (n,p) Cross Section for Unstable Nuclide 60Co by Multi-Step Hauser-Feshbach Model with Pre-Equilibrium Correction

Abstract

The cross section of the (n, p) reaction for unstable target nuclide ⁶⁰Co was estimated by a multi-step Hauser-Feshbach model code with pre-equilibrium correction. Parameters used in the model calculations were determined from the fitting of the cross sections to existing experimental data of (n, p), (n, α) and (n, 2n) cross sections and particle emission spectra for the adjacent stable nuclide ⁵⁹Co. The present result for ⁶⁰Co(n, p)⁶⁰Fe was compared with the values estimated from semi-empirical formulae around 14 MeV, The prediction accuracy of the present calculation is considered to satisfy the requirement for the fusion reactor applications. The theoretical model calculations with a reliable parameter set are recommended rather than the semi-empirical formulae for the important activation cross sections of exotic target nuclei including unstable ones.     

~6Li+~(208)Pb光学势灵敏半径的能量相依性

光学势灵敏区域的确定是研究光学势性质的先决要素。本工作利用扰动法,抽取并研究了弱束缚体系~6Li+~(208)Pb光学势灵敏区域的能量相依性。结果表明,该体系光学势实部和虚部的灵敏区域均呈现多峰结构。内部的灵敏区域对应体系库仑势垒的穿透过程,其位置基本不随能量的变化而改变;而外部的灵敏区域则对应体系的表面相互作用过程,并且存在强烈的能量相依性。采用新的灵敏区域重新检测了~6Li+~(208)Pb光学势的性质,结果表明在新的灵敏区域内,~6Li+~(208)Pb光学势虚部表现出传统的阈异常现象,而并非之前所观察到的破裂阈异常现象。     

186W(p,n)186Reg的激发函数和厚靶产额的计算

为计算¹⁸⁶W(p,n)¹⁸⁶Re^g反应的激发函数,收集了EXFOR实验数据库中的一些实验数据并对其进行了分析修正。将修正过的实验数据与EMPIRE程序理论计算得到的数据进行了比对,以此来选择合适的光学模型势和能级密度参数,给出了¹⁸⁶W(p,n)¹⁸⁶Re^g反应截面的推荐值。利用得到的激发函数计算了医用放射性核素¹⁸⁶Re^g的厚靶产额,并给出了相应的推荐值。     

Evaluation of Computational Models for Fission and Spallation Reactions Used in Accelerator Breeding and Transmutation Analysis Code

Computational models for spallation and fission reactions used in an accelerator breeding and transmutation code have been evaluated by performing calculations for thin targets of Bi, Pb, Th and U in the energy range of 50–1,000 MeV. Proton and neutron non-elastic and fission cross sections have been derived from the counts of real collisions and fission events in the targets.

Several fission models in combination with a spallation model are compared with the experimental data due to Steiner et al. and Schimmerling et al. A good agreement has been obtained for a model with the level density parameters a_n = A/10 and a_f/a_n fitted to the data due to Il'inov et al. The mass dependence of the non-elastic cross sections has been calculated also with the use of the best fit model. A good agreement with the experimental data was obtained over a wide range of nuclear masses.     

Study on the Two-Dimensional Density Distribution for Gas Plasmas Driven by Laser Pulse

We perform an experimental study of two-dimensional(2D) electron density profiles of the laser-induced plasma plumes in air by ordinarily laboratorial interferometry. The electron density distributions measured show a feature of hollow core. To illustrate the feature, we present a theoretical investigation by using dynamics analysis. In the simulation, the propagation of laser pulse with the evolution of electron density is utilized to evaluate ionization of air target for the plasma-formation stage. In the plasma-expansion stage, a simple adiabatic fluid dynamics is used to calculate the evolution of plasma outward expansion. The simulations show good agreements with experimental results, and demonstrate an effective way of determining 2D density profiles of the laser-induced plasma plume in gas.     

类镁离子磁四极3s~2 ~1S_0-3s3p ~3P_2(Z=20~103)禁戒跃迁

采用全相对论多组态Dirac-Fock方法,对高离化类镁离子的磁四极3s2 1 S0-3s3p 3 P2(Z=20~103)自旋禁戒跃迁的能级间隔、跃迁波长、跃迁概率和振子强度等光谱跃迁参数进行了系统计算,计算中考虑了重要核的有限体积效应、Breit修正和QED修正,所得结果和最近已有的实验数据进行了比较。结果表明,高原子序数的高电荷离子(Z≥70)磁四极自旋禁戒跃迁几乎可与中性原子的光学允许跃迁相比拟,不仅在天体等离子体中,在ICF和MCF高温激光等离子体中,磁四极自旋禁戒跃迁和其他自旋禁戒跃迁(磁偶极、电四极)一样不容忽视,在双电子复合、不透明度、自由程等理论计算中应考虑其影响。     

热分析法测量中子通量密度的探测器材料选择

热分析法测量中子通量密度是一种新测量方法,它基于热分析技术测量经中子辐照后的探测器材料所放出的退火热量。选择合适的探测器材料是对该方法进行研究的前提,工作的主要内容是根据该测量方法的原理采用多种含10B物质进行实验研究,选出合适的探测器材料。通过对实验结果的对比分析,总结出了热分析法探测器材料需要满足的条件,并初步选定晶体硼与磷灰石的混合物作为热分析法探测器材料,为以后进一步的研究提供参考。