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2004年  第21卷  第4期

邀请报告
多夸克态研究概况
张宗烨
2004, 21(4): 263-265. doi: 10.11804/NuclPhysRev.21.04.263
摘要:
介绍了多夸克态研究的重要性,侧重介绍了最近发现的5夸克态的实验和理论研究现况.
27,28P+28Si总反应截面增强及可能相关的机制
刘祖华, 阮明, 赵跃林, 张焕乔, 杨峰, 马中玉, 林承键, 陈宝秋, 吴岳伟, 詹文龙, 郭忠言, 肖国青, 徐瑚珊, 孙志宇, 李加兴, 陈志强
2004, 21(4): 266-270. doi: 10.11804/NuclPhysRev.21.04.266
摘要:
测量了27,28P和相应同中子异位素在28Si靶上的中能反应截面.测得N=12和13同中子异位素的反应截面在Z=15处突然增大.对Z≤14同中子异位素和28P的实验数据结果可以用改进的光学极限近似的Glauber理论很好地描述.28P的反应截面能够用扩大核芯以改进的Glauber理论来解释.但是,用改进光学极限和少体近似的Glauber理论却低估了27P的实验数据.理论分析表明,扩大的核芯加质子晕可能是响应27P+28Si反应截面增强的机制. The reaction cross sections of~(27,28)P and the corresponding isotones on Si target were measured at intermediate energies. The measured reaction cross sections of the N=12 and 13 isotones show an abrupt increase at Z=15. The experimental results for the isotones with Z≤14 and~(28)P can be described well by the modified Glauber theory of the optical limit approach. The enhancement of the reaction cross section for~(28)P could be explained by the modified Glauber theory with an enlarged core. Theoretical ana...
远离稳定线核研究进展
靳根明, 付芬, 黄熙
2004, 21(4): 271-275. doi: 10.11804/NuclPhysRev.21.04.271
摘要:
近几年在对远离核的实验研究中,观测到了理论预言的新衰变模式,如45Fe的双质子衰变,β-缓发裂变;对中子滴线外一些核的存在可能性也进行了较多的实验探索和理论分析;开始了对人们一直关注的中子集团存在可能性的实验探索.远离核谱学和衰变性质研究逐渐深入,通过对一些远离核第一激发态能量的系统比较和许多远离核β衰变Q值的测量,以及核质量的精确测量,发现在远离核区,原有的一些幻数消失,代之产生了一些新的幻数,对其产生原因的理论分析做了简要的综述. Recently the predicted new decay model, for instance two-proton decay and β~(-)delayed fission have been observed in the investigations of the nuclei far from stability line. The existence of the nuclei located beyond the drip-line has already been studied experimentally and theoretically. It has been started to search for the neutron cluster in experiment by using neutron-rich nuclei. The researches of the spectroscopy and decay properties of the nuclei far from stability line are more and deeper, and...
原子能院的核天体物理研究和串列升级工程进展(英文)
柳卫平, 李志宏, 白希祥, 王友宝, 连钢, 曾晟, 颜胜权, 王保祥, 赵志祥, 张天爵, 唐洪庆, 杨丙凡, 关暇令, 崔保群
2004, 21(4): 276-283. doi: 10.11804/NuclPhysRev.21.04.276
摘要:
在北京串列实验室建立了次级束流实验装置 ,用于放射性核束物理和核天体物理研究 .先后开展了7Be(d ,n) 8B ,11C(d ,n) 12 N ,8Li(d ,p) 9Li和6 He(p ,n) 6 Li核天体物理重要反应的研究 .介绍了串列加速器升级工程的进展情况 .该工程在现有串列加速器的基础上 ,将建立 10 0MeV/ 2 0 0 μA的质子回旋加速器、在线同位素分离器和超导加速段 .在此装置上 ,将可以产生质量数最高为 12 0 ,强度最高为 10 9particles/s的放射性束流 . A secondary beam line (GIRAFFE) at the Beijing Tandem accelerator lab was constructed for yielding low energy secondary beams. The current progress on the study of nuclear astrophysics and nuclear structure is presented. Up to now, We have carried out measurement of~(7)Be(d, n)~( 8)B,~(11)C(d, n)~(12)N,~(8)Li(d, p)~(9)Li, and~(6)He(p, n)~(6)Li reactions. The proposed Beijing radioactive nuclear beam facility (BRIF ) and its current R&D progress are briefly introduced. This facility is based on...
正电子能量转换研究进展
王少阶
2004, 21(4): 284-285. doi: 10.11804/NuclPhysRev.21.04.284
摘要(1001)
摘要:
简要介绍了正电子能量转换的原理、优点、重要应用前景及主要研究领域. The concept of positron energy conversion, the advantages of positrons, the possible applications and main research area of positron energy conversion were reviewed in this paper.
中高能物理
夸克平均场模型研究有限核及超核
申虹
2004, 21(4): 286-288. doi: 10.11804/NuclPhysRev.21.04.286
摘要:
采用组分夸克模型描述重子,首先由自由核子及超子的性质定出模型参数,进一步考虑核介质中重子性质的变化,核介质中的介子平均场直接与重子内部的组分夸克相互作用.夸克平均场模型已被用于研究有限核及超核的性质,能够给出令人满意的有限核及超核的性质,该模型也预言了核介质中核子体积的膨胀及核子有效质量的降低. The quark mean field model, which describes the baryon by using the constituent quark model, is applied to study the properties of finite nuclei and hypernuclei. The meson mean fields couple directly with the quarks and change the properties of baryons in nuclear medium. The quark mean field model provides satisfactory results on the properties of spherical nuclei and hypernuclei. It also predicts an increasing size of the nucleon as well as a reduction of the effective mass in the nuclear environment.
超核物理学进展
李磊, 谭玉红, 王秋玲, 罗延安, 钟显辉, 宁平治
2004, 21(4): 289-293. doi: 10.11804/NuclPhysRev.21.04.289
摘要:
简要评述超核物理学近几年的发展,包括常规超核和非常规超核两个方面.对于包含通常超子的常规超核,重点介绍近来在日本KEK完成的一批超核实验及其理论分析.对其中关于超子杂质效应和超子平均自由路程等实验测量结果进行了理论分析,得到一些有意义的结果.并对奇异数为S=-2的Ξ超核的结构和性质进行了若干研究.对于包含C夸克或B夸克的其他味超核,以及可能的包含pentaquark的θ+超核也做了适当的介绍. Progress and recent status of experimental and theoretical investigations on hypernuclear physics are briefly reviewed, including conventional hypernuclear physics and unconventional hypernuclear physics. We introduce the recent progress of hypernuclear experiments in KEK, Japan and the studies of fine structure in γ-ray spectroscopy of Λ hypernuclei. The spin-flip transition between the ground-state spin doublet of light hypernuclei has been observed and the transition energy provides important..
Dirac粒子的正-反粒子自由度和正-反粒子量子数
王顺金, 周善贵, H.C.Pauli
2004, 21(4): 294-297. doi: 10.11804/NuclPhysRev.21.04.294
摘要:
对Dirac粒子引进了正 反粒子自由度和相应的内部τ空间的算子,把γ矩阵分解成自旋σ算子和正 反粒子τ算子;Dirac方程的解出现了正 反粒子量子数;正 反粒子变换是Dirac粒子的哈密顿量的反对称变换,Dirac粒子负能态能量的负值来自正 反粒子量子数的负值;γ矩阵这种分解是处理物理相互作用的需要. he particle-antiparticle degrees of freedom and the corresponding intrinsic space are introduced to study the dynamical symmetry of the Dirac particle. As a result, the particle-antiparticle quantum number appears naturally and the Dirac particle has five quantum numbers instead of four. An anti-symmetry of the Dirac Hamiltonian and a dual symmetry of its eigen functions are explored. The operator of the Dirac equation in central potentials is found to be the analog of the helicity operator of ...
介子束缚态相对论本征方程的非微扰重整化
王顺金, 周善贵, H.C.Pauli
2004, 21(4): 298-299. doi: 10.11804/NuclPhysRev.21.04.298
摘要:
介子结合态本征方程中δ相互作用可用T矩阵进行非微扰重整化,深入理解重整化的一些基本问题:物理结果与重正化点的选取无关,T矩阵非微扰重整化的物理实质. Nonperturbative T-matrix renormalization of the relativistic eigen equation for meson mass spectra is described and the expressions for eigen mass spectra and eigen wave functions are given.
相对论夸克模型对重夸克偶素质量谱的研究
梅花, 陈洪
2004, 21(4): 300-305. doi: 10.11804/NuclPhysRev.21.04.300
摘要:
介绍了量子场论中基于准势途径的一个相对论夸克模型,并使用这个相对论夸克模型计算了重夸克偶素的质量谱.显示这个相对论夸克模型可较好地拟合实验上肯定的质量谱数据. A relativistic quark model based on the quasipotential approach in quantum field theory is briefly introduced, and by using this model, heavy quarkonium mass spectra are calculated in detail. It is shown that such a model can give results which are in agreement with the observed experimental data on the mass spectra.
U(4)过渡区理论中的介子质量谱
张宇, 潘峰
2004, 21(4): 306-308. doi: 10.11804/NuclPhysRev.21.04.306
摘要:
利用U(4)振动子模型的过渡区理论来描述q q位形介子的结构.对实验数据比较完整的57个介子的质量进行了拟合,并与O(4)极限的计算结果以及唯象QCD理论的计算结果进行了比较.结果表明,利用过渡区理论对介子质量谱的描述比O(4)极限更为精确. A mass formula of q mesons is formulated based on the transitional theory in the U(4) vibron model, in which accurate fitting to 57 experimentally well-established masses of mesons is carried out. The results show that the transitional theory seems to be much better than the O(4) limit consideration in the description of mass spectra of q mesons. A comparison of the results from the transitional theory to those from the O(4) limit calculation and QCD potential model is also shown.
HIRFL-CSRm内靶实验终端CsI(Tl)电磁量能器性能模拟
李文飞, 徐瑚珊, 孙志宇, 肖国青, 詹文龙, 郭忠言, 段利敏, 李加兴, 徐华根, 陈若富, 张雪荧, 贾飞, 祁辉荣, 马越, 张宏斌
2004, 21(4): 309-311. doi: 10.11804/NuclPhysRev.21.04.309
摘要:
基于GEANT4模拟了HIRFL CSRm内靶实验终端的CsI(Tl)电磁量能器系统,给出了CsI电磁量能器的最佳设计参数及可能达到的性能.结果表明,设计的CsI(Tl)电磁量能器系统能够满足所研究的物理要求. Based on the GEANT4, the performance of the electromagnetic calorimeter (EMC) of the internal-target detector at HIRFL-CSRm is simulated. The simulation results show that 1.5%—3% of the energy resolution σ_E/E and 2° of the polar angular resolution σ_θ can be obtained. The invariant mass of the π~0 decay can be reconstructed well. The performance can meet the requirement of studying the proposed physics at HIRFL-CSRm.
HIRFL-CSRm内靶实验终端上TPC性能的Monte-Carlo研究
贾飞, 徐瑚珊, 李文飞, 段利敏, 孙志宇, 徐华根, 陈若富, 马越, 张雪荧
2004, 21(4): 312-314. doi: 10.11804/NuclPhysRev.21.04.312
摘要:
基于Monte Carlo方法对HIRFL CSRm上的TPC的性能进行了模拟.研究了磁场、读出电极几何尺寸、灵敏丝距以及读出电极平面与灵敏丝平面之间的距离等参数对TPC性能的影响,给出了TPC的一些最佳设计参数. Based on Monte-Carlo method the time projection chamben s (TPC s) performance at HIRFL-CSRm has been simulated. We have already studied the effect of magnetic field, wire space, the size of readout pad and the distance between the pad plane and the wire plane on the performance of TPC. At the same time some important results are given for designing TPC.
核结构
A=130区缺中子核122Cs与134Ce高自旋态研究
朱胜江, 禹英男, 甘翠云, 朱凌燕, M.萨哈伊, 肖树冬, 李明亮, 车兴来, 温书贤, 竺礼华, 吴晓光, 李广生
2004, 21(4): 315-319. doi: 10.11804/NuclPhysRev.21.04.315
摘要:
通过重离子核反应与在束γ谱的实验技术,对A=130缺中子核区122Cs与134Ce核的高自旋态进行了研究,所用核反应分别为107Ag(19F,1p3n)与122Sn(16O,4n).实验结果扩展了122Cs与134Ce的能级纲图.在122Cs中发现可能是属于手征二重带的结构,而在134Ce核的高自旋态结构中呈现出重要的具有不同γ形变的形状共存特性.Through heavy ion nuclear reaction and in-beam γ-ray spectroscopy technique, the high spin states of neutron-deficient~(122)Cs and~(134)Ce nuclei in A=130 region have been studied. The~(107)Ag(~(19)F, 1p3n) and~(122)Sn(~(16)O, 4n) reactions were used. The previous level schemes of~(122)Cs and~(134)Ce have been extended. Possible chiral doublet bands in~(122)Cs have been observed and a shape coexistence with different γ values in~(134)Ce are suggested.
双奇核172Re高自旋态实验研究
张玉虎, 王华磊, 周小红, 柳敏良, M.Oshima, Y.Toh, M.Koizimi, A.Osa, A.Kimura, Y.Hatsukawa, T.Morikawa, M.Nakamura, M.Sugawara, H.Kusakari, T.Komatsubara, K.Furuno
2004, 21(4): 320-323. doi: 10.11804/NuclPhysRev.21.04.320
摘要:
利用149Sm(27Al,4nγ)172Re反应布居了形变双奇核172Re的高自旋态,用12套带有BGO反康普顿抑制的高纯锗探测器阵列进行了在束γ实验测量,首次建立了172Re由3个转动带构成的高自旋态能级纲图.研究和讨论了3个转动带的结构特征,基于已有的高自旋态核结构知识并通过系统学比较和分析指出它们的准粒子组态分别为πh11/2 νi13/2,πh9/2 νi13/2和 π1/2-[541] ν1/2-[521].发现前两个转动带在自旋小于18时其转动能级呈现反常的旋称劈裂.High-spin states in the odd-odd~(172)Re have been investigated via the~(149)Sm(~(27)Al, 4nγ)~(172)Re reaction through excitation functions, X-γ and γ-γ coincidence measurements. A level scheme consisting of three rotational bands have been identified for the first time extending the high-spin studies of A≈160 odd-odd nuclei to the currently lightest rhenium isotope. The three bands have been assigned to be built on the πh_(11/2) νi_(13/2), πh_(9/2) νi_(13/2 ) and π1/2~-\ν1/2~-\ configurations ...
α结团模型在形变核区域的推广
任中洲, 许昌
2004, 21(4): 324-325. doi: 10.11804/NuclPhysRev.21.04.324
摘要:
将α结团模型推广至形变核,计算偶偶形变母核α衰变基态到子核基态和子核第一激发态的分支比,显示出α衰变精细结构的测量是提取核形变信息的有效手段.The cluster model of α-decay is extended to deformed nuclei. The branching ratios of α-decays from the ground state of a parent nucleus to the ground state 0~(+) of its deformed daughter nucleus and to the first excited state 2~(+) are calculated in the framework of the cluster model. The results indicate that a measurement of α spectroscopy is a feasible method to extract the information of nuclear deformation.
非常缺中子Re核的负三轴形变研究(英文)
周小红, 张玉虎, 宋立涛, 郑勇, 徐岩冰
2004, 21(4): 326-330. doi: 10.11804/NuclPhysRev.21.04.326
摘要:
利用在束核谱学实验技术,建立了169Re基于9/2-[514]组态的强耦合转动带.该带在已知的奇ARe核中具有最大的低自旋旋称劈列.对于奇ARe中的9/2-[514]转动带,研究了它们的能量旋称劈列和M1跃迁矩阵元相对旋称劈列与核形状偏离轴对称的关系,揭示了非常缺中子的奇ARe核具有相当的负三轴形变. High-spin states in~(169)Re were studied and resulted in the identification of a strongly coupled band based on the 9/2~(-)\ Nilsson state. The 9/2~(-)\ band in~(169)Re shows the largest signature splitting at low spin among the known odd mass Re isotopes. For the 9/2~(-)\ bands in light odd-A Re isotopes, the signature splitting of the Routhians and its relation with the signature dependence of M1 transition matrix elements are investigated in connection with the deviation of nuclear shape from axial symme...
125Cs的能级结构
马英君, 小松原哲郎, 王守宇, Cederwall B, Nyberg J, 张玉虎, 古野兴平, 李容俊, Sletten G, Hagemann G, Jensen H, Gjorup N, 刘运祚
2004, 21(4): 331-333. doi: 10.11804/NuclPhysRev.21.04.331
摘要:
通过116Cd(14N,5n),Ebeam=65MeV的核反应布居了125Cs的高自旋态.利用在束γ谱学实验方法,进行了γ-γ符合测量,使已知的125Cs核能级纲图得到了扩展,并且修正了某些组态的带头激发能.High-spin states in odd-A nucleus~(125)Cs have been studied via the~(116)Cd(~(14)N, 5n) reaction at 65 MeV bombarding energy. γ-γ coincidences were recorded with the NORDBALL detector array at Niels Bohr Institute in Denmark. After careful data analysis, most of the previously-known bands have been confirmed and 5 new rotational sequences have been identified. Spin/parity and configuration assignments are tentatively proposed for all of the observed bands. In addition, the bandheads of the 9/2~(+)and (1/2~...
p-n相互作用对1/2~-[541]带带交叉频率延迟的影响
赵广义, 刘运祚
2004, 21(4): 334-335. doi: 10.11804/NuclPhysRev.21.04.334
摘要:
通过转动框架下的经验近似,提取了A=160区4个核的剩余p n相互作用对1/2-[541]带的带交叉频率延迟的影响.结果表明,对于奇Z核中1/2-[541]带的带交叉频率的延迟,剩余p n相互作用的影响大约占二分之一左右,表明剩余p n相互作用在其中起着很重要的作用.We estimated the effect of residual p-n interaction on the crossing frequency delay of the 1/2~(-)\ band of four odd-Z nuclei through the empirical method. The result shows that about half of the shift in crossing frequency in the 1/2~-\ band is the effect of residual p-n interaction. The residual p-n interaction plays a very important role in the crossing frequency delay of the 1/2~(-)\ band.
171Ta高自旋态能级寿命测量
张振龙, 竺礼华, 吴晓光, 王治民, 贺创业, 王月, 孟锐, 马瑞刚, 崔兴柱, 李广生, 温书贤, 郑勇, A.A.Pastrernak, 周宏余, 刘运祚, 杨春祥
2004, 21(4): 336-338. doi: 10.11804/NuclPhysRev.21.04.336
摘要:
在中国原子能科学研究院的HI 13串列加速器上通过157Gd(19F,5n)171Ta重离子熔合蒸发反应布居了171Ta的高自旋态,以多普勒移动衰减法的峰形分析法分析了171Tah9/2质子1/2[541]转动带的6条能级的寿命,得到了这6条能级的平均寿命值. The high spin states of~(171)Ta have been populated via heavy ion fusion evaporation reaction~(157)Gd(~(19)F, 5n)~(171)Ta at the HI-13 tandem accelerator in China Institute of Atomic Energy. The lifetimes of the high spin states in~(171)Ta have been measured by using the Doppler Shift Attenuation Method (DSAM). Six levels of its h_(9/2) proton 1/2\ band have been analyzed and their lifetimes have been deduced from the experimental data.
奇奇核90Nb的高自旋态研究
崔兴柱, 竺礼华, 吴晓光, 李广生, 温书贤, 王治民, 贺创业, 张振龙, 孟锐, 马瑞刚, 骆鹏, 郑勇, 霍俊德, M. M. Ndontchueng
2004, 21(4): 339-342. doi: 10.11804/NuclPhysRev.21.04.339
摘要:
用能量为80MeV的19F束通过反应76Ge(19F,5n)90Nb布居了90Nb的高自旋态.通过在束γ测量分析90Nb退激γ射线的符合级联关系,发现了19条新的属于90Nb的γ跃迁,建立了90Nb的高自旋态能级纲图.通过经验壳模型计算指定了部分能级的组态,并结合实验DCO比值和与相邻N=49核素的系统比较,确认了新能级的自旋和宇称. The high spin states of~(90)Nb have been populated via reaction~(76)Ge(~(19)F, 5n)~(90)Nb at beam energy of 80 MeV. The de-exciting γ-rays have been measured with in-beam γ-ray spectroscopy method. After γ-γ coincidence analysis, 19 new γ transitions were identified and assigned to~(90)Nb. The new level scheme of~(90)Nb was established. Based on the semi-empirical shell model calculations, the configurations of the levels have been suggested. In addition, the spins and parities of the new levels ...
相互作用玻色子模型中振转过渡区的特征研究
潘峰, J.P.Draayer
2004, 21(4): 343-345. doi: 10.11804/NuclPhysRev.21.04.343
摘要:
详细研究了相互作用玻色子模型中U(5)振动极限到SU(3)转动极限的相变行为.通过对能谱和E2跃迁强度等的分析,说明了在临界点的核具有最大的非刚性. Transitional patterns from the U(5) vibrational limit to the SU(3) rotational limit in the interacting Boson model are studied in detail. The transitional behavior of low-lying energy levels, isomer shifts, E2 transition rates, and some other related quantities across the entire region are investigated. The results show that nuclei in the critical region are most non-rigid.
154Er核三轴超形变核态存在的微观机制
于少英, 安广朋, 图雅
2004, 21(4): 346-348. doi: 10.11804/NuclPhysRev.21.04.346
摘要:
利用TRS方法计算了154Er核的总位能面,讨论了其存在三轴超形变核态的微观机制. Based on TRS theory the total routhian surface for~(154)Er nuclei is calculated, the result indicates it exists TSD state.
164Lu的三轴超形变核态的理论计算
于少英, 王小明
2004, 21(4): 349-350. doi: 10.11804/NuclPhysRev.21.04.349
摘要:
用三维TRS(totalrouthiansurface)自洽理论对奇奇核164Lu的位能面进行了计算,计算结果与实验上得到的ε2=0.38基本一致,从而从理论上确认了164Lu是三轴超形变核,并且指出了存在三轴超形变带的两个组态. Total routhian surface in~(164)Lu nuclei is calculated according to the three dimensional Total Routhian Surface (TRS) theory. The result of the calculation is in agreement with the experiment. At the same time, two TSD bands could be assigned to the configuration(π\(1/2), α=1/2)(ν\(5/2), α=1/2), (π\(1/2), α=1/2)(ν\(3/2), α=-1/2).
原子核配对壳模型——侵入态与原子核形变
罗延安, 潘峰, 宁平治
2004, 21(4): 351-354. doi: 10.11804/NuclPhysRev.21.04.351
摘要:
利用原子核配对壳模型讨论了侵入态对原子核形变的影响.计算结果表明,侵入态具有削弱原子核形变的趋势,对原子核的形变起着重要作用. The influence of intruder level on nuclear deformation is studied within the framework of the nucleon-pair shell model truncated to an SD-pair subspace. The results suggest that the intruder level has a tendency to reduce the deformation and plays an important role in determining the onset of rotational behavior.
RMF理论框架下用粒子数守恒方法处理对关联
郭建友, 孟杰, 张双全
2004, 21(4): 355-357. doi: 10.11804/NuclPhysRev.21.04.355
摘要:
在相对论平均场理论框架下,利用粒子数守恒方法处理对关联,给出了具体的理论公式和数值细节;并以24Ne为例,用该方法研究了它的基态和低激发态性质. Particle-number conserving method is adopted to treat the pairing correlations in the relativistic mean-field theory. The formalism and numerical techniques are presented. As an example, the ground state properties and low-lying excited states in~(24)Ne are studied.
原子核的单粒子共振态
张时声, 孟杰, 周善贵, G.C.Hillhouse
2004, 21(4): 358-359. doi: 10.11804/NuclPhysRev.21.04.358
摘要:
采用基于相对论平均场的耦合常数解析延拓方法研究球形核的单粒子共振态.具体计算了Zr同位素链中巨晕核的核芯核122Zr阈值附近的中子共振态的能量、宽度和波函数,其结果同相应的散射相移法的结果一致. Using analytic continuation in the coupling constant (ACCC) method within the framework of the self-consistent relativistic mean field (RMF) theory, the energies, widths and wave functions for single-particle resonant states close to the continuum threshold are evaluated. Predictions are also compared with corresponding results obtained by the scattering phase shift method.
A≈100和130核区手征双重带的描述
彭婧 孟杰 张双全
2004, 21(4): 360-362. doi: 10.11804/NuclPhysRev.21.04.360
摘要:
利用三轴形变的粒子 转子模型讨论了A≈100和A≈130核区手征双重带.基于粒子空穴组态πh11/2 νh-111/2的计算很好地再现了A≈130核区N=75同中子素的手征双重带实验能谱.通过分析基于组态πg9/2 νg-19/2的约化跃迁几率B(E2)和B(M1)研究A≈100核区可能的手征双重带. The Chiral doublets for nuclei in A≈100 and 130 regions have been studied with the particle-rotor model. The experimental spectra of chiral partner bands for four N=75 isotones in A≈region have been well reproduced by the calculation with the configuration πh_(11/2)νh~(-1)_(11/2). The possible chiral doublets in A≈100 region have been predicted by the particle-rotor model (PRM) with the configuration πg_(9/2) νg~(-1)_(9/2) based on the analysis of the B(M1) and B(E2) transition probabilities.
超重核的球形和变形壳结构
吴哲英, 许甫荣
2004, 21(4): 363-367. doi: 10.11804/NuclPhysRev.21.04.363
摘要:
应用宏观 微观模型系统研究了超重核的形状和结构性质.其中,宏观能是由基于核子密度泛函的连续介质模型计算得到.计算结果很好地再现了超重核的结合能、α衰变能和寿命的实验数据.对单粒子能级的计算和分析表明超重核的壳结构是形变和同位旋相关的.位能曲面的计算结果显示,与其它区域的核相比,超重核的形状不易变化. The structure of superheavy nuclei has been studied by using the macroscopic-microscopic model. The macroscopic energy was calculated with the continuous medium model in which the energy is expressed as a functional of nucleon densities. The deformations and structures of superheavy nuclei were investigated systematically. Calculations reproduce well the available data of experimental α decay energies and half-lifes. The investigation of single-particle levels shows that the shell structure is deformed a...
超重核的壳结构
张炜, 孟杰, 张双全, 耿立升, H.Toki
2004, 21(4): 368-369. doi: 10.11804/NuclPhysRev.21.04.368
摘要:
在相对论连续谱Hartree Bogoliubov(RCHB)理论框架下,在质子数Z=100—140和中子数N=Z+30—2Z+32等偶偶核中进行了超重球形双幻核的探索.采用的有效相互作用为NL1,NL3,NLSH,TM1,TW 99,DD ME1,PK1和PK1R.基于对双核子分离能(S2p和S2n)、双核子能隙(δ2p和δ2n)、壳修正能量(Epshell)、对能(Eppair和Enpair)和有效对能隙(Δp和Δn)等物理量和能shell和En级结构的分析,预言了可能的质子幻数和中子幻数,并观察到在超重核区壳的弱化现象. The magic proton and neutron numbers are searched in the superheavy region with proton number Z=100 —140 and neutron number N=(Z+30) — (2Z+32) by the relativistic continuum Hartree-Bogoliubov (RCHB) theory with interactions NL1, NL3, NLSH, TM1, TW99, DD-ME1, PK1, and PK1R. Based on the two-nucleon separation energies S_(2p )and S_(2n) , the two-nucleon gaps δ_(2p) and δ_(2n), the shell correction energies E~p_(shell) and E~n_(shell), the pairing energies E~p_(pair) and E~n_(pair), and...
核反应
超重核合成中的靶核形变效应
刘祖华, 包景东
2004, 21(4): 370-373. doi: 10.11804/NuclPhysRev.21.04.370
摘要:
利用额外推力模型研究了48Ca+238U超重核合成过程中的靶核形变效应.计算表明,在近垒和垒下能区,靶核形变使超重核合成截面明显增强.对于48Ca+238U反应,由于靶核形变蒸发残余截面增大了几倍.同时与球形靶核相比,形变靶核时蒸发残余激发函数的峰位移向较低能量.Effects of target deformation on the synthesis of superheavy nucleus~(283)112 are investigated in the framework of extra-push model. Our results show that the cross sections of the 3n evaporation residue in the~(48)Ca+~(238)U reaction for the case of β_2=0.275 are several times larger than those of β_2=0. Meanwhile, the peak position of ER excitation function in the case of deformed target is shifted to the lower energy as compared to the one of spherical target.
QMD模型的改进及其在低能重离子反应中的应用
王宁, 李祝霞, 吴锡真
2004, 21(4): 374-378. doi: 10.11804/NuclPhysRev.21.04.374
摘要:
丰中子核以及重核熔合机制的研究以及中能重离子碰撞中多重碎裂的研究都迫切需要一个统一的、自洽的微观动力学模型.经过对量子分子动力学模型进行根本的改进,发展了一个新的、适用于低能以及中能重离子反应的统一描述的微观动力学模型.改进的量子分子动力学(ImQMD)模型能够将整个熔合反应过程中的动力学效应、同位旋效应以及弹靶质量不对称效应等比较全面地、自洽地考虑进来,从而给熔合反应的研究提供了一个新的途径.ImQMD模型能够很好地再现一系列核的基态性质以及10多个熔合反应的激发函数(包括丰中子核熔合体系以及实验最新测量的132Sn+64Ni熔合体系).此外还运用该模型初步探索了重核熔合过程中复合体系的寿命与体系的入射能量、体系大小以及体系的中子质子比的依赖关系. We have developed a new microscopic dynamical model called improved quantum molecular dynamical model (ImQMD). This model can describe the fusion process at energies near the Coulomb barrier as well as the multifragmentation process at intermediate energies in heavy-ion collision (HIC) uniformly. By using this model, fusion cross sections (including some of neutron-rich nuclei reactions and that of newly measured~(132)Sn+~(64)Ni fusion reaction) of tens reactions can be reproduced remarkably well. In fusi...
激发核系统中最大Lyapunov指数、密度涨落以及多重碎裂之间的关系
张英逊, 吴锡真, 李祝霞
2004, 21(4): 379-381. doi: 10.11804/NuclPhysRev.21.04.379
摘要:
基于量子分子动力学模型,系统地研究了从48Ca到298114一系列核素在不同温度下的最大Lyapunov指数、密度涨落以及体系多重碎裂之间的关系.发现最大Lyapunov指数随温度变化有一峰值出现(该峰值所对应的温度为"临界温度"),在该临界温度时体系的密度涨落达到最大,碎块的质量分布能够给出较好的PowerLaw指数.通过对最大Lyapunov指数与密度涨落随时间变化行为的研究,发现密度涨落的时间尺度要大于混沌的时间尺度,意味着混沌的概念可以用来研究体系的多重碎裂过程.最后还给出了有限体系相变的临界温度随体系大小变化的规律. Within a quantum molecular dynamics model we calculate the largest Lyapunov exponent (LLE), the density fluctuation, and the mass distribution of fragments for a series of nuclear systems at different initial temperatures. It is found that the LLE peaks at the temperature ("critical temperature") where the density fluctuation reaches a maximal value and the mass distribution fragments is fitted best by the Fisher s power law from which the critical exponents for mass and charge distribution are obtain...
轻中等质量核非对称裂变研究的新进展
樊铁栓
2004, 21(4): 382-384. doi: 10.11804/NuclPhysRev.21.04.382
摘要:
介绍了轻中等质量核非对称裂变研究的新进展.通过对64,58Ni+12C和78,82,86Kr+12C反应复杂碎片的激发函数测量,发现流行的转动液滴模型和转动有限力程模型均不能复现实验的非对称裂变位垒数据.The excitation functions were measured for complex fragments with atomic number Z=4—25 emitted from the compound nuclei~(70,76)Se and~(90,94,98)Mo produced in the reactions~(64,58)Ni+~(12)C and~(78,82,86)Kr+~(12)C. The extracted mass asymmetric fission barriers have been compared with those calculated from macroscopic nuclear models.
平均最后通过时间和热核裂变速率
贾莹, 包景东
2004, 21(4): 385-386. doi: 10.11804/NuclPhysRev.21.04.385
摘要:
提出利用平均最后通过鞍点时间计算热核裂变速率,结果表明平均最后通过鞍点时间的倒数比平均首次通过断点时间的倒数更接近朗之万数值模拟值. The mean last passage time is introduced to instead of the mean first passage time for studying the decay of an induced-fissioning system. The stationary fission rate determined by the inverse of mean last passage time across the saddle point is agreement with the resulting rate of Langevin simulation and better than that of mean first passage time arriving at the scission point.
19F+27Al深部非弹性碰撞产物的角分布
董玉川, 王琦, 李松林, 段利敏, 吴和宇, 徐华根, 陈若富, 徐瑚珊, 韩建龙, 李志常, 路秀琴, 赵葵, 周平, 刘建成, Sergey Yu-kun
2004, 21(4): 387-388. doi: 10.11804/NuclPhysRev.21.04.387
摘要:
完成了19F+27Al深部非弹性碰撞产物的角分布测量.初步分析了反应产B,C,N,O,F,Ne,Na,Mg和Al的实验室系角分布,展现出深部非弹性反应机制的特点,显示了反应系统随时间的演化过程. Angular distributions of fragments produced in the deep inelastic collision of~(19)F+~(27)Al have been measured for incident energy of 114 MeV at θ_(lab)= 9~(o), 24~(o), 40~(o), 55~(o), 70~(o) and 85~(o). Angular distributions of dissipative products B, C, N, O, F, Ne, Na, Mg and Al are analyzed to provide an evolution process of the intermediate dinuclear system formed in the reaction.
(n,p)和(n,α)激发函数半经验计算方法
樊胜, 阎芳, 张鸿洲, 赵志祥
2004, 21(4): 389-390. doi: 10.11804/NuclPhysRev.21.04.389
摘要:
在En≤20MeV的情况下,忽略了粒子的二次发射过程,认为复合系统的形成截面是能量相关的,得到了理论模型清晰、公式形式简单的半经验计算方法.在靶核23≤A≤209的范围内,利用大量(n,p)和(n,α)反应的截面实验数据对可调参数进行了研究,得到了参数对靶核的N和Z以及入射能量的依赖关系.对得到的参数做了定性的解释,利用普适参数对(n,p)和(n,α)反应的激发函数做了预言,预言值在其误差范围内与实验数据一致. To simplify the calculation, some assumptions are considered at present work. The preequilibrium emission is the first step in the equilibrium process, which is characterized by exciton n=3 and "never come back" are considered at the preequilibrium emission process; the proton and alpha emissions are only competed with the neutron emission, the second particle emission is neglected. A semiempirical method of the cross section for (n, p ) and (n, α) reactions were obtained on the basis of evaporatio...
利用MSDM分析p+208Pb散裂反应产物
樊胜, 阎芳, 张鸿洲, 赵志祥
2004, 21(4): 391-393. doi: 10.11804/NuclPhysRev.21.04.391
摘要:
多步动力学模型(MSDM)研究中、高能质子引起的散裂反应分为3个过程:核内级联、粒子预平衡发射以及通过蒸发粒子和裂变方式的剩余激发核退激发过程.利用Ignatyuk能级密度公式代替MSDM模型中的费米气体能级密度公式,改进其研究质子入射引起散裂产物的形成截面.采用Ignatyuk能级密度公式MSDM研究p+208Pb散裂产物的电荷、质量分布以及产物核形成截面,结果很好地再现了实验数据,且比利用费米气体能级密度的MSDM结果好得多. The level density of Ignatyuk formula is introduced into the Many stages dynamics model ( (MSDM)) instead of Fermi-gas formula to improve the simulation of spallation fragments. The results of (MSDM) with Ignatyuk formula reproduced the experimental data well for the mass and charge distributions, the formation cross sections of isotopic product of proton-induced spallation on~(208)Pb. The calculations are in agreement with the experimental data and better than some simulations by MSDM with Fermi-gas ...
中高能质子入射反应散裂碎片的半经验方法研究
张鸿洲, 樊胜, 孙秀泉
2004, 21(4): 394-397. doi: 10.11804/NuclPhysRev.21.04.394
摘要:
简要分析了质子入射核反应的半经验研究方法,指出半经验研究方法应该建立在独立产额数据之上,而目前半经验研究方法主要是建立在以往的累积产额数据之上.通过对最新的实验得到的独立产额数据并结合MSDM的计算结果的分析,发现描述散裂质量分布的参数应该分为与能量有关和无关两个部分,并指出这与快过程平衡时间的不同有关. We analyzed the former solution of semi-empirical methods, which is first funded by G. Rudstam. On this basis, we pointed out that all the former solutions are basically based on so-called cumulative reaction data not on independent data. On the analysis of newly data measured by GSI, we founded that mass distribution of spalltion production could be divided to two parts: one is independent on induced-energy, but on the mass number of target; one is dependent on energy. Also, we argued that such...
60 MeV/u 18O离子同天然铀反应钡同位素截面的测定
杨维凡, 徐岩冰, 袁双贵, 牛雁宁, 丁华杰
2004, 21(4): 398-399. doi: 10.11804/NuclPhysRev.21.04.398
摘要:
通过60MeV/u18O离子照射天然铀靶产生Ba放射性同位素,使用BaCl2沉淀法从大量铀和其它反应产物混合物中分离出Ba.通过离线γ谱学方法测量了Ba样品的γ射线单谱,根据Ba同位素特征γ射线峰的强度及其它相关数据计算了Ba同位素的生成截面.发现在厚铀靶的情况下,缺中子Ba同位素仍有较高的截面.
The radioactive Ba isotopes were produced by 60 MeV/u~(18)O ion bombardment of natural uranium. Ba was separated from U and the reaction product mixture by BaCl_(2) precipitation. The Ba fraction was measured by off-line γ-ray spectroscopy. The cross sections of the individual Ba isotope were calculation based on the intensities of the character γ-ray peaks of Ba isotopes and other relative information. It was found that the n-deficient Ba isotopes have higher cross sections using the thick uranium targets.
轻核(n,x)反应微分截面的实验测量
张国辉, 陈金象, 唐国有, 施兆民, 陈泽民, Yu.M.Gledenov, M.Sedysheva, G.Khuukhenkhuu
2004, 21(4): 400-403. doi: 10.11804/NuclPhysRev.21.04.400
摘要:
对本课题组十几年来的(n,x)反应实验研究工作进行了评述.介绍了屏栅电离室的特点、构造与工作原理.用屏栅电离室在北京大学4.5MV静电加速器上测量了1—7MeV中子6Li(n,t)4He和10B(n,α)7Li反应的微分截面与截面,对实验结果进行了讨论. Our research work on (n, x) reaction for more than one decade is reviewed. The characteristics, structure, and working principle of the gridded ionization chamber are discussed. Differential cross sections and cross sections of the~(6)Li(n, t)~(4)He and~(10)B(n, α)~(7)Li reactions were measured in the neutron energy range of 1—7 MeV by using the GIC method. Experiments were carried out at the 4.5 MV Van de Graaff accelerator of Peking University. Results of the measurement are discussed.
利用加速器质谱方法测量14N(16O,α)26Al反应截面
何明, 杨耀云, 姜山, Y.Nagashima, T.Takahashi, 刘克新, 董克君, 任小唐, 武绍勇
2004, 21(4): 404-406. doi: 10.11804/NuclPhysRev.21.04.404
摘要:
Al是核天体物理非常重要的一个核素,14N(16O,α)26Al的反应截面可能是天体26Al的一个来源.介绍了利用AMS方法测量14N(16O,α)26Al反应截面的过程,包括靶的照射、化学分离、26Al原子数的AMS方法测量及最后的核反应截面值.The~(26)Al is one of the important nuclide in the astrophysics. The reaction, namely~(14)N(~(16)O, α)~(26)Al, may be one of the origin of the source of~(26)Al in the cosmic. The procedures of the cross section measurement with accelerator mass spectrometry (AMS) method are discussed, In this paper, the irradiation experiment, chemical separation and~(26)Al measurement are described. The results of cross-section (around) sub-barrier energies are also represented.
裂变位垒参数的推荐和裂变位垒参数库
苏宗涤, 王书暖, 冯仁发, 周建明, 史淑梅, 王斌, 朱耀银, 李支文, 黄忠甫, 刘建峰, 戴能雄, 王豫生, 张本爱
2004, 21(4): 407-411. doi: 10.11804/NuclPhysRev.21.04.407
摘要:
通过分析和计算锕系核裂变截面和全套中子反应截面获取了一组锕系核的裂变位垒参数.Fm)在此基础上,广泛收集实验裂变位垒参数,通过比对和评价,推荐了本组的129个核素(109Cd—255的实验裂变位垒参数.此外,对收集的不同裂变位垒参数作了分析与评价,推荐了7组实验和1组模型计算的裂变位垒参数,并组建了中国评价核参数库裂变位垒参数子库(CENPL FBPL). The fission barrier parameters for actinide nuclei were obtained by analysis and calculations of fission cross-sections and complete neutron reaction cross sections. A lot of experimental fission barrier parameters from different authors were collected. A set of fission barrier parameters for 129 nuclei ranging from~(109)Cd~( ) to~(255)Fm were recommended after performing comparisons, evaluations and systematics extrapolations for these extracted fission barrier parameters in model calculations of fissi...
核数据共享研究
于洪伟, 金永利, 葛智刚
2004, 21(4): 412-414. doi: 10.11804/NuclPhysRev.21.04.412
摘要:
科学数据共享的重要性已经引起了我国政府的重视,介绍了中国核数据中心在核数据共享项目进行的研究工作.该研究工作主要包括建立核数据数据库和共享平台的建设两方面的内容.The importance of scientific data sharing has been attracted attention of our government. The research of nuclear data sharing in China Nuclear Data Center are introduced. The work includes research of nucler database and development of online service system.
混合评价核数据库HENDL1.0/MG/MC研制
许德政, 高纯静, 郑善良, 刘海波, 朱晓翔, 李静惊, 吴宜灿, FDS Team
2004, 21(4): 415-418. doi: 10.11804/NuclPhysRev.21.04.415
摘要:
根据世界几个主要核评价数据库,如ENDF/B 6(美国)、JEF 2.2(欧盟)、JENDL 3.2(日本)、BROND 2.2(俄罗斯)、CENDL 2.1(中国)和FENDL 2(IAEA/NDS),兼顾聚变、裂变以及聚变 裂变次临界混合堆设计研究的多种需要,经过甄别、筛选,最后集成为包含213个核素的基本评价文件,名为HENDL1.0/E的核评价数据库.在此基础上,利用目前流行的群常数加工程序系统NJOY和输运截面制备程序TRANSX制作两套用于中子或/和光子输运计算的输运截面工作库:①参考Vitamin J能群结构制作了175群中子和42群光子、中子 光子耦合多群工作数据库HENDL1.0/MG,可用于离散纵标Sn法程序计算;②连续能群结构、紧凑ENDF(ACE)格式中子截面库HENDL1.0/MC,可用于蒙特卡罗方法输运计算,如MCNP.另外还制作了可用于燃耗(嬗变)计算的燃耗库BURNUP.LIB和响应函数库RESPONSE.LIB两个专用数据库.同时,也对HENDL1.0综合评价核数据库的有效性进行了抽样测试、基准检验和初步确认. A Hybrid Evaluated Nuclear Data Library(HENDL) named as HENDL1.0 has been developed by Fusion Design Study (FDS) team of Institute of Plasma Physics, Academia Sinica (ASIPP) to take into account the requirements in design and research relevant to fusion, fission and fusion-fission sub-critical hybrid reactor. HENDL1.0 contains one basic evaluated sub-library naming HENDL1.0/E and two processed working sub-libraries naming HENDL1.0/MG and HENDL1.0/MC, respectively. Through carefully comparing...
氘通量在钯中引发的异常核现象
李兴中, 刘斌, 魏清明
2004, 21(4): 419-421. doi: 10.11804/NuclPhysRev.21.04.419
摘要:
以氚产生、氘通量在钯中引发的核嬗变和热流为例介绍凝聚态核科学(冷聚变)研究动态. Tritium production and the nuclear transmutation induced by deuterium flux inside Pd are described in order to illustrate the condensed matter nuclear science.
冷核聚变十五年
江兴流, 刘锐, 王怀义, 乐小云, 韩丽君, 文雄伟
2004, 21(4): 422-424. doi: 10.11804/NuclPhysRev.21.04.422
摘要:
参考在美国麻省理工学院召开的第十届国际冷核聚变会议(ICCF 10)内容,对冷核聚变研究的现状作一简单介绍.国际原子能委员会(IAEA)分管聚变的官员(1995—2001年)T.J.Dolan在清华召开的ICCF 9国际会议上的总结会上提出五种重要的解释冷聚变现象的理论模型,其中有江兴流提出的涡旋动力学模型.涡旋动力学模型的主要论点在于:局域瞬态非平衡体系产生涡旋,而涡旋的内聚作用和极化效应,使体系内的粒子相互靠近,产生局域极化核反应和高度定向的轴向加速高能粒子.这种局域瞬态非平衡体系出现在电极微突起处或多层膜的非平衡点处.这一理论成功地解释了许多异常放热和核嬗变现象,因而受到了广泛重视.对涡旋动力学作以简单介绍. Many papers published in the 10th International Conference of Cold Fusion( MIT, Massachusetts .Aug. 2003) reveal the experimental results of excess heat with a few of products of nuclear reactions. Over the years it is become clear that there are new effects to be surfaced. Thomas J. Dolan listed several interesting theoretical ideas including the model of vortex dynamics proposed by Xingliu Jiang. This model says that excess heat and nuclear reactions in electrical discharge system and other transient...
瞬态涡旋动力学与非平衡体系中的异常核现象
江兴流, 刘志坚, 文雄伟, 韩丽君
2004, 21(4): 425-427. doi: 10.11804/NuclPhysRev.21.04.425
摘要:
根据实验现象和已发表的数据,对电解过程中的尖端效应、磁自收缩现象、阴极表面电化学双层的高能集中、极化核聚变的产生进行了分析研究.利用CR 39固体径迹探测器记录到电化学系统中高度集中而且准直的10MeV以上的异常高能带电粒子.提出了涡旋动力学理论解释电化学放电过程中的异常现象———过剩热和非平衡系统中的异常核现象. The tip effect, magnetism self-pinch phenomena, high energy concentration on the cathode surface, electrochemical double layer, and polarized nucleus fusion in the process of electrolysis have been studied and discussed. The high concentrated and straight charged particles with energy above 10 MeV in (electrochemistry) systems were recorded by CR-39 solid trace detector. The hypothesis of vortex dynamics is proposed for explaining the peculiarities of excess heat and anomalous nucleus phenomena...
水中碳弧的异常放电现象
王志刚, 江兴流
2004, 21(4): 428-429. doi: 10.11804/NuclPhysRev.21.04.428
摘要:
放电过程中的磁收缩效应产生超高密度的等离子体细丝,有可能发生核聚变反应.在高纯水中,用光谱纯的碳棒作电极,进行低压(-20V)电弧放电实验,收集放电产生的磁屑,并用离子光谱法和中子活化法进行分析,观察到碳屑中铁的含量从几个10-6增加到几百、上千个10-6,而且,同位素的丰度与天然铁的丰度有所变化. There exist various phenomena for electric discharge, such as radiation with wide bands, collective acceleration, electron degeneracy and "linear atom", etc. which occur in dense state of matter.The arcing was created in the gap between two purified carbon rods in deionised water. The original carbon contained a few millionth iron, and the detritus contained up to thousands millionth iron based on the analysis by an (atomic) emission spectroscope (AES). It is deduced that the plasma filaments...