Nuclear fusion rates from resonant states of 3Hedμ molecular ion

We present new theoretical calculations of nuclear fusion rates λ _f ^J from the resonant states of the muonic molecular ion ³Hedμ ⁺⁺ with total angular momenta J=0,1. As a byproduct, new very accurate variational wave functions for these states have been obtained. Using these wave functions, the probability density |Ψ(R=0)|² in a fusion region has been calculated by extrapolating the variational solution to small internuclear distances by means of the multi-channel adiabatic solution. Calculated fusion rates for the states J=0 and J=1 are: λ _f ⁰ =1.9·10⁵s^-1 and λ _f ¹ =0.65·10³s^-1, respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

Fission experiments with secondary beams

Nuclear fission from excitation energies around 11 MeV was studied at GSI, Darmstadt for 76 neutron-deficient actinides and pre-actinides by use of relativistic secondary beams. The characteristics of multimodal fission of nuclei around ²²⁶Th are systematically investigated and related to the influence of shell effects on the potential-energy and on the level density between saddle point and scission. A systematic view on the large number of elemental yields measured gave rise to a new interpretation of the enhanced production of even elements in nuclear fission and allowed for a new understanding of pair breaking in fission.     

卢瑟福散射与原子的有核模型

回顾了卢瑟福散射实验,并从原子的有核模型的建立引出一些思考。     

Average Nuclear Binding Energies in a Lee-Wick Type Model

We find: (i) The Lee-Wick type relativistic mean-field theory with finite nucleon size effect can reproduce the binding energies for all nuclei over the nuclide table quite well. For 1654 nuclei, whose mass numbers range from 16 to 263 and charge numbers range from 8 to 106, the calculated binding energies are near to the corresponding experimental values with a systematical deviation of about 5.74%. (ii) The lowering of the calculated nuclear masses, by including Coulomb energy into the variational calculations, is very small.     

Optical fibre beam delivery of high-energy laser pulses: beam quality preservation and fibre end-preparation

This paper investigates the extension of optical fibre beam delivery to high-brightness applications, in particular laser percussion drilling, where both a good beam quality and high peak power are required. Beam quality preservation through a number of optical fibres is studied both experimentally and by using a ray propagation model. It is determined that in order to achieve the beam quality required for percussion drilling (M²<30) the largest fibre which can be used is 400 μm diameter. The laser-induced damage threshold is measured for a number of 400 μm fibres, and a CO₂ laser-annealing technique is shown to increase the damage threshold by a factor of 10, allowing 28 J, 1 ms pulses to be transmitted.     

核破裂中的激发能的作用

在晶格气体模型的框架中研究了¹²⁹Xe系统在破裂过程中的热力学性质和轻粒子发射性质随核温度和系统的冻结密度的变化规律.计算发现在不同的冻结密度下,¹²⁹Xe破裂过程的物理观测量呈现了不同的温度相关性.在这种情况下,核物质液气相变发生时的临界温度强烈地依赖于系统的冻结密度.当激发能代替温度作为一个自变量时,临界激发能将不再灵敏地依赖于系统的冻结密度.除此之外,由于不同冻结密度而引起的不同粒子发射产额的温度相关性,也随着激发能的应用,出现了几乎一致的激发能依赖性.从这些结果中可以认为,激发能可以作为一个控制核破裂的基本物理量和标度量.     

FST模型中核物质的不可压缩系数

FST模型是近来提出的一个具有手征对称性的核模型.用它研究了零温及有限温核物质的不可压缩系数.并与其它模型得出的结果进行了比较.     

碎裂反应和放射性核束的产生

本总结了中能重离子碰撞产生同位素分布的计算方法和模型,包括参数化公式,擦碎模型和统计擦碎模型。介绍了模型的物理基础和计算方法,并讨论了对擦碎模型和统计擦碎模型的修正。同时用统计擦碎模型探讨了碎裂瓜在产生的同位素分布的同位旋效应。然后介绍了放射性核束的产生方法,并对放射性束流物理的发展前景作了简要介绍。     

Resonant X-ray scattering from a rotating medium: The Nuclear Lighthouse Effect

A coherently excited nuclear state is carried with a rotating sample so that its radiative decay is redirected by the rotation angle that has developed during its lifetime. As a result, the time spectrum of the nuclear decay is mapped to an angular scale. This effect has been observed in nuclear resonant scattering of synchrotron radiation from a rotating ⁵⁷Fe metal foil. Applications with respect to elastic and inelastic nuclear resonant scattering are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

193T1超形变带K=1/2的可能性

分析了脱耦合项对于原子核转动惯量的重要影响.总结了奇质量核K=1/2带转动惯量变化规律的新特点.在此基础上讨论了¹⁹³T1中3条新的超形变带的内部结构.目前尚无足够证据能够确认它们都是K=1/2带.