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2003年  第20卷  第3期

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核物理
重子谱现状及兰州CSR可开展的N*研究项目(英文)
邹冰松
2003, 20(3): 167-175. doi: 10.11804/NuclPhysRev.20.03.167
摘要:
概述了重子谱研究现状及在北京正负电子对撞机通过J/Ψ衰变开展重子谱研究的最新进展.探讨了在兰州CSR可开展的核子激发态研究项目. Status of baryon spectroscopy and recent progress of the baryon program from J/Ψ decays at Beijing ElectronPositron Collider (BEPC) are briefly reviewed. Possible N* program at Lanzhou CSR is discussed.
62-76Zn核的低能谱和电磁跃迁的相互作用玻色子模型(英文)
白洪波, 刘凤英, 李岩松, 周光荣, 张进富
2003, 20(3): 176-181. doi: 10.11804/NuclPhysRev.20.03.176
摘要:
采用相互作用玻色子模型研究了62—76Zn核的低能正宇称态的能谱和电磁跃迁.应用一个简单的哈密顿量能够较好地描述它们的能谱和电四极跃迁.研究表明,62—76Zn同位素核基本上属于U(5)到O(6)的过渡核.Spectra and E2 transition rates for the eveneven 62-76Zn isotopes are studied in the framework of the interacting boson model. A schematic Hamiltonian capable of describing their spectra and transition is used. It is found that the eveneven 62-76Zn isotopes are in the transition from U(5) to O(6) dynamical symmetry.
奇A核101Pd和101Ru的负宇称带能谱研究
徐延冰
2003, 20(3): 182-185. doi: 10.11804/NuclPhysRev.20.03.182
摘要:
将具有正宇称的gds组态空间扩大到包含具有负宇称的1h11/2轨道,采用修正的表面δ相互作用(MSDI)对101Pd和101Ru两个奇A核进行了形变HF计算,得到了基态和一些激发态的解.同时,还用近似角动量投影形变Hartree Fock(PDHF)方法对101Pd和101Ru进行了能谱计算,得到其正、负宇称带的解,计算结果与实验谱基本一致. Using modified delta interaction, enlarging the gds configuration space to include the 1h11/2 orbital with negativeparity, the deformed HartreeFock calculations for both nuclei: 101Pd and 101Ru are performed. Their groundstate and some excited configurations are obtained. The approximate angular momentum projected deform HartreeFock (PDHF) method is also applied to nuclei 101Pd and 101Ru, and both of their positive and negative parity bands are obtained...
光致反应中的极化实验和遍举测量
石宗仁, 邢雨, 徐鹍, 顾嘉辉, 蔡翔舟, 沈文庆
2003, 20(3): 186-192. doi: 10.11804/NuclPhysRev.20.03.186
摘要:
以γN→πN′反应为例说明了极化实验的类型、自旋观测量同独立幅度的关系、实验上如何得到自旋观测量及实现完全测量等.也介绍了极化固体靶的原理和结构、靶材料的选取原则和适合遍举测量的4π型谱仪及其国际状况等.光致反应中的极化实验和遍举测量将是使用SLEGS从事核物理实验的重要手段. The relationship between polarization observables and indepedent amplitudes, measurements of polarization observables and complete measurement for γN→πN′ are illustrated. The principle and structure of polarization nucleon solid targets, the principle of choosing target material and 4π detectors suitable for exclusive measurements are discussed. The polarization experiments and exclusive measurements are very singnificant for SLEGS.
钚同位素成分及总质量测量的可行性探讨
师学明, 刘成安
2003, 20(3): 193-196. doi: 10.11804/NuclPhysRev.20.03.193
摘要:
利用MCNP4B程序,通过一个实例探讨了钚的同位素成分及总质量测量的理论可行性.首先利用假想的γ射线源确定出不同能量γ射线穿透容器的相对效率曲线;然后将实际的钚样品放入容器,通过容器外各种特征γ射线强度的测量可以推算出钚的同位素成分;最后测量出系统总中子泄漏数,便可求得钚的总质量. One possible method of measurement of isotopic composition and mass for plutonium is discussed and its feasibility in theory is demonstrated by the MCNP4B package in this paper. The relative efficiency ratio curve for the container where the plutonium sample is put in can be computed by assigning an arbitrary γ ray source in the sample . Once the relative efficiency ratio for the container is known, the isotopic components for plutonium can be induced by assigning the real γ ray source in the sample and...
加速器
HIRFL的辐照治癌终端
朱昆, 张金泉, 唐靖宇, 尹全民, 詹文龙
2003, 20(3): 197-200. doi: 10.11804/NuclPhysRev.20.03.197
摘要:
为了进行重离子束流的肿瘤治疗和生物效应的研究,HIRFL正在建造一个辐照治癌终端.主要介绍了该终端的束流制备方法和束流线的布局、性能参数和束流光学设计计算结果. A new experimental terminal is being constructed at HIRFL for research program of proton and heavy ion therapies and irradiation effects of living things . The beam preparation method and the layout, performance and beam optics calculation of the beam line are presented.
交叉学科
加速器-电子显微镜联机进行材料科学研究的新进展
蒋昌忠, 任峰, 张丽, 石瑛, 范湘军
2003, 20(3): 201-207. doi: 10.11804/NuclPhysRev.20.03.201
摘要:
离子或电子辐照引起的材料微结构演变是一个非常复杂的过程.用加速器 电子显微镜联机装置可原位观察载能离子束辐照及辐照后退火引起的材料微结构演变,并确定相应的辐照条件.介绍了近10年来国际上利用加速器 电子显微镜联机装置开展材料科学研究的最新进展.Ion beam or electronbeam irradiation will lead to the change of material microstructure. By the use of facilities composed of an electron microscope and ion accelerator(s), the microstructure evolvement in material can be insitu studied during the irradiation and following annealing processes. The facilities have been widely used to study many kinds of materials, e.g. metal, alloy, ceramic materials and semiconductor, in the past twenty years. In this paper the development of the Accelerator and Electron ...
缀饰原子的简化波函数(英文)
李书民, 陈激, 周子舫, 张声涛
2003, 20(3): 208-212. doi: 10.11804/NuclPhysRev.20.03.208
摘要:
作为含时薛定谔方程的微扰近似解,在速度规范下给出了激光场中缀饰原子的一个波函数.利用平均激发能近似和完备关系,可将此波函数简化为一个含时的相乘算符作用于无场时的"裸原子"态上.在软光子近似下,平均激发能仅出现在光场频率的一阶和二阶项上.此波函数适用于计算激光辅助的散射过程,特别是重排过程. A wave function for laser dressed atom is derived as a perturbative solution of the timedependent Schrdinger equation in the velocity gauge. With the use of the average excitation energy approximation and the closure approximation, the solution is reduced to a timedependent operator acting on the "bare" atomic state. In softphoton approximation, the average excitation energy only appears in the first and second order terms of field frequency. Such a simplified dressed wave function is useful in...
正电子寿命-动量关联技术
叶邦角, 翁惠民, 周先意, 韩荣典
2003, 20(3): 213-217. doi: 10.11804/NuclPhysRev.20.03.213
摘要:
评述了国际正电子领域的新探测技术———寿命 动量关联技术.介绍了该技术的发展过程,讨论了该技术的分析方法,详细阐述了该技术在Ps形成和热化过程中的应用,并讨论了该技术在Ps化学上的应用.A new detection technique--age momentum correlation in international positron field is reviewed. The recent development is described and the analysis methods are discussed for the technique. The application of the technique in the positronium formation and thermalization processes are systematically summarized. Besides the application of the technique in Ps chemistry is discussed.
低能离子注入小麦种子胚内的射程分布
卫增泉, 袁世斌, 颉红梅, 赵力民, 毛淑红
2003, 20(3): 218-221. doi: 10.11804/NuclPhysRev.20.03.218
摘要:
采用110keV56Fe1+离子束垂直注入小麦种胚后,将小麦沿腹面的纵沟掰开,形成剖面,将剖面水平朝上粘贴在金属铜托上,用扫描电镜在剖面上从胚表面向纵深进行点分析,测定不同深度上由Fe元素激发出的特征X射线强度,由此得到了该种离子注入小麦胚内的最大射程约5μm,最可几射程为0.935μm.并对这种低能离子注入作物种子能诱发突变的机理进行了详细讨论. After embryo of wheat seed was right implanted by 110 keV 56Fe1+ions, the seed was broken into two parts by hand along its abdomen trench to form two crosssections. A halfseed was pasted on a metal holder in keeping the crosssection upwards horizontal. Spot analyses were carried out from embryo surface towards depth on the crosssection under SEM and the intensity of characteristic X rays induced by electrons in Fe elements of the embryo was measured. From this, the maximum range of the ionsi...
正弦平方势与带电粒子的准沟道辐射
胡西多, 邵明珠, 罗诗裕
2003, 20(3): 222-225. doi: 10.11804/NuclPhysRev.20.03.222
摘要:
在经典力学框架内,描述了带电粒子自发辐射的频谱分布与辐射频率;利用正弦平方势讨论了带电粒子准沟道辐射,指出了准沟道辐射与系统的旋转周期解相联系;分析了系统的相平面特征和准沟道粒子进入混沌的可能途径. In the general case the spectral distribution and the radiation frequency are derived for the spontaneous radiation of charged particles. The quasichanneling radiation is described by using a sinesquare potential, and point out that the quasichanneling radiation is related directly to the rotation periodic solution; The properties of the phase plane and the possible model approaching to chaos for the system is analyzed.
ENDF-VI库次级中子数据的能量守恒问题
伊炜伟, 田东风, 孙伟力
2003, 20(3): 226-230. doi: 10.11804/NuclPhysRev.20.03.226
摘要:
在评价核数据库ENDF VI版的出射粒子能量分布数据(即文档5)中,一些核素在阈能附近的次级中子能量分布大多采用简单的近似方法描述,例如三角形分布或矩形分布.这些简单的近似描述,将导致产生散射矩阵的"双峰"现象,或使平均次级中子能量过大而产生负KERMA(ki netic energy release in materials)因子.针对这两个现象,通过细致的分析,讨论了这些现象的产生原因,并试对相关数据做一定的修正,以改善次级中子分布的能量守恒问题. In file 5 of ENDF VI, the arbitrary tabulated function (L=1) was applied to some threshold reactions of some nuclides. The energy distribution of secondary spectrum was given approximately as a triangular shape or rectangular shape at the threshold energy for some nuclides. The triangular shape distributions would cause twopeaked energy distribution near the threshold energy, which must affect the group transfer matrix. The rectangular shape make the E′n too large, that may lead to...