核子微探针技术的新进展

综述了核子微探针技术在显微分析和显微成像两方面的进展,一些应用新的显微成像技术的实例,说明了它对科学研究所起的重要作用． This paper reviews the recent progress of the nuclear microprobe technology in both micro-analysis and micro-imaging.Some examples of recent applications of its microimaging technology are enclosed to show the potentialities of the technology for a variety of scientific studies.     

核探针技术及其应用

核探针的概念起源于电子探针,它综合了离子束分析技术的特点,已成为很有应用前景的分析工具.本文结合上海新建成的核探针,介绍它们的原理、结构和部分应用. In concept,the scanning nuclear microprobe is similar to the scanning electron micro-probe,but has much higher sensitivity for microanalysis.The main features and the construction of thenew-built Nuclear Microprobe in Shanghai are described.It has been proved to be an ideal tool for mi-croanalysis in the fields of medical and biology,metallurg,microelectronics,archaeology and earthsciences.Its potentiality is demonstrated with examples in the applications of these fields.     

复旦大学核微探针系统

复旦大学现代物理研究所利用国家“211工程”的资助,从英国Oxford Microbeams公司引进了微探针关键部件,建立了新的核微探针实验装置.介绍了该装置各个组成部分,包括束线,靶室,聚集、扫描系统以及数据采集系统等.现已得到线度为μm量级的离子束.A nuclear microprobe was set up at the Institute of Modern Physics of Fudan University.The key parts were imported from Oxford Microbeams Ltd.The hardware system of the microprobe,including beam line,target chamber,focusing system and DAQ system is introduced. About several micrometer could be achieved at present beam spot size.     

核子质量、 半径及夸克凝聚的核物质密度依赖性

简要介绍核物质中核子的质量、 半径及夸克凝聚的密度依赖关系基于QCD模型和QCD有效场论研究的现状, 并具体介绍整体色对称模型（GCM）的研究结果. GCM研究表明, 在小于临界密度的情况下, 核物质中核子的质量随核物质密度的增大而减小, 核子的半径和夸克凝聚随核物质密度的增大而增大. 当达到临界密度时, 核子质量减小为零, 核子半径变为无限大, 夸克凝聚突变为零, 进而提出一个核物质中手征对称性恢复的新机制. The status of the investigations on the nucleon mass, nucleon radius and quark condensate in the framework of QCD inspired models and QCD effective field theories is briefly reviewed. The results in the global color symmetry model (GCM) are described a little detailedly. The calculated results indicate that, before the maximal density is reached, the mass of a nucleon in nuclear matter decreases, the radius of a nucleon and the quark condensate increase very slowly, with the increase of the nuclear matter density. As the maximal nuclear matter density is reached, the mass of the nucleon vanishes gradually. The radius becomes infinite and the quark condensate vanishes suddenly. A new mechanism for the chiral symmetry restoration in nuclear matter is proposed.     

晕核的标度定律

利用重叠函数的渐近归一化常数(ANC)计算了一系列核的价核子处于核外的几率及价核子密度分布的均方根半径〈r2〉1/2. 由于实验上抽取的核ANC近似与模型参数无关,因此由核ANC计算的核外几率和均方根半径是考察晕核的可靠且有效的观察量. 依价核子处于核外的几率大于50%为条件， 证实了一些核为晕核， 且给出了比较宽松的晕核出现的条件. 此外， 还用〈r2〉/R2≥1.5及〈r2〉1/2/rc≥2.0为判据考察了一系列晕核候选者. 最后， 利用r2算符在有限方势阱中的预期值给出了晕核的标度定律. We have extracted the probability for a valence particle being out the binding potential, as well as the root mean square radius of the probability distribution from the measured nuclear asymptotic normalization coefficients. According to the criterion of nuclear halo, i.e., the valence particle has larger than 50% probability being out of the nuclear binding potential, a number of halo nuclei have been confirmed. Based on these results, we have obtained a very relaxed condition for nuclear halo formation. In addition, a number of nuclear halo candidates have been analyzed with the criteria of 〈r2〉/R2≥1.5 and 〈r2〉1/2/rc≥2.0. Furthermore, we present the scaling laws for the dimensionless quantity 〈r2〉/R2 of the nuclear halo in terms of an analytical expressions of the expectation value for the operator r2 in a finite square well potential.     

QCSH:A full quantum computer nuclear shell-model package

The nuclear system is a promising area for demonstrating practical quantum advantage.A comprehensive computation of a nuclear system in a classical computer is beyond the capacity of current classical computers.With the rapid development of hardware,the prospect of using quantum computers in nuclear physics is close at hand.In this paper,we report a full quantum package,QCSH,for solving a nuclear shell model in a quantum computer.QCSH uses the linear combination of the unitary formalism of quant...     

核物质中的夸克凝聚

核物质中的夸克凝聚是在夸克层次研究核物理遇到的基本问题之一,特别是,它与核环境下强子性质的研究紧密相关．近年来,国内外对此开展了若干研究．简要介绍这方面的研究现状和指出存在的问题． Quark condensates in nuclear matter are one of the key problems for the study of nuclear physics at quark lever, and it is related closely to a deeper understanding of the properties of hadrons in nuclear matter. Recently we have seen some investigations made of the above subject. The present status and open problems are described in this paper.     

Superfluid nuclear matter in BCS theory and beyond

Medium polarization eflects are studied for 1S0 pairing in nuclear matter within BHF approach. The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The self-energy corrections are consistently included resulting in a strong depletion of the Fermi surface. The self-energy effects always lead to a quenching of the gap, whereas it is almost completely compensated by the anti-screening effect in nuclear matter.     

Energy Loss Effect in High-Energy Drell-Yan Dimuon Process

By means of the nuclear parton distribution obtained from DGLAP equation,measured Drell-Yan production cross sections for 800 GeV proton incident on a variety of nuclear targets are analyzed within Glauber framework with takes into account energy loss of the beam proton.It is shown that the theoretical results are in good agreement with the FNAL E866．     

深海富钴结核微区X射线荧光光谱分析和数据挖掘

西太平洋富钴结核是近年来新发现的海底固体矿产资源,富含Mn,Fe,Co,Ni和Cu等多种关键金属元素。富钴结核是一种非均质的地球化学和矿物学集合体,粒径约6 cm的结核在生长过程中记录了数千万年的海洋沉积历史,亟需高分辨率的分析技术揭示古海洋环境信息。采用微区X射线荧光光谱仪（μ-XRF）,对C3BC1704富钴结核开展多元素面扫描,获得了原位高分辨率多元素的信号强度数据,评价了μ-XRF技术在富钴结核中的应用质量。元素信号谱峰特征和数据频谱分布结果显示,富钴结核中Mn,Fe,Ti,Co,Ca和Ni等元素信号强度敏感,数据呈现相对较好的正态分布特征,可用于定量或半定量分析;Si,Cu和Al等元素信号较弱,数据呈现左偏的正态分布特征,建议相关数据仅作参考。μ-XRF获得的数据量庞大且彼此独立,本研究将不同元素连接成彼此关联的多维矩阵,实现了数据的位置信息和特征元素之间的数学运算和筛选,了解了金属元素的分布和变化特征,揭示了富钴结核生长过程的环境变化。结果显示,Mn和Fe等元素在生长层中波动剧烈,金属元素在富钴结核中的分布极不均匀,显示出多成因类型的交替微层和7个大的生长周期旋回。C3BC1704富钴结核主体暴露在海水中,金属元素主要来自海水,化学组成指示为典型的水成成因。进一步定量分析结果显示,Mn,Cu和Ni等元素含量从内部向外围呈现同步降低的趋势,Fe,Ti和Co等元素含量则呈现同步升高的趋势,这些特征指示早期偏向于成岩富集环境,晚期则以水成富集为主。富钴结核金属元素的分布和变化特征,清晰呈现了富钴结核的生长结构,揭示了富钴结核生长过程的环境变化,有利于富钴结核的成矿模型的构建。     

X-ray fluorescence determination of major elements in ferromanganese nodules

In this article, the X-ray fluorescence technique is proposed for the quantitative determination of major elements in ferromanganese nodules and crusts, which is a necessary stage of the oceanic ferromanganese deposits investigation and development. The research was performed using a wavelength-dispersive spectrometer S4 Pioneer (Bruker AXS, Germany). Certified reference materials of ferromanganese nodules, cobalt-bearing ferromanganese crusts and pelagic sediments were dried and prepared by two different techniques: the pressing of powder samples on a boric acid substrate and the homogenization by fusion with lithium tetraborate in an electric furnace at 1050°C. For each sample preparation technique, different forms of calibration curves (linear or quadratic) and methods of matrix effect correction (fundamental parameters or empirical intensities coefficients) were examined. The uncertainty of the proposed technique was assessed by analyzing the certified reference material FeMn-1 and by comparison with the atomic absorption spectrometry, flame photometry and spectrophotometry results. Analysis of both fused beads and pressed pellets provides a quantitative determination of the major elements in the oceanic ferromanganese nodules.     

空气中痕量铀的现场光度法测定

作为一种天然放射性金属元素,铀及其化合物可以地气为分散系,以气溶胶形式稳定存在并随空气迁移。气相中铀可经多种途径对人体造成放射性危害,而其浓度变化与该区域核能开发与利用有关。因此,对空气中铀的快速现场检测具有现实意义。采用普通气泵对低品位铀矿石上方的空气进行采样,并以2.0 mol·L-1硝酸溶液对气体进行吸收,向溶液中添加固体试剂包,对溶液中微量铀进行显色后以手持式光度计进行现场光度分析。结果表明：对于普通低品位铀矿石样品,空气中铀含量可用本方法检出,该方法多次测定的RSD为1.72%,其结果与ICP-MS分析结果一致。将该方法用于区分铀矿石和其他矿石,具有成本低廉,操作方便,结果准确可靠等优点。     

微束核反应及其对流体包裹体的应用

本文主要介绍了扫描质子探针中微束核反应分析原理。给出了用８７２ｋｅＶ质子能量的＾１９Ｆ（ｐ,αγ）＾１６Ｏ共振反应测量氟元素的方法,并利用扫描质子探针对地幔流体包裹体内的氟元素含量进行了测量。     

Mössbauer study of ilmenite-limonite concrete for nuclear reactor shield

A heavy type concrete for nuclear reactor shield prepared by adding to the portland cement Egyptian iron ores has been studied. This concrete contains heavy elements and a large amount of water of crystallization that make it more effective than ordinary concrete for neutron and gamma attenuation. The measurement of the Mössbauer parameters allows a deeper understanding of the relations between attenuation and physical properties.     

Use of IR Absorption Laser Spectroscopy at Nuclear Fuel Cycle Plants: Problems and Prospects (Review)

The main stages of the nuclear fuel cycle from extraction of uranium ores to disposal of radioactive waste resulting from the processing of spent nuclear fuel were briefly analyzed. A list of the most probable radioactive substances and toxic chemicals that can be part of emergency emissions at each stage of the nuclear fuel cycle was composed. The basic physical principles of local and remote IR absorption laser technologies for detecting radioactive substances and toxic chemicals in the atmosphere for solving some unique problems of environmental monitoring were considered. The analytical potential of the currently most effective laser technologies for atmospheric monitoring at nuclear fuel cycle plants based on the achievements of diode laser spectroscopy, cavity ringdown laser spectroscopy, and optoacoustic laser spectroscopy using diode and quantum-cascade lasers was discussed. Current trends in the development of laser technologies for atmospheric monitoring in different IR spectral ranges were analyzed.     

Proton beam scanning modular unit for a nuclear microprobe

General ideas underlying the design of a proton beam scanning modular unit intended for a nuclear microprobe consisting of a ferromagnetic x-y scanning system and a dynamic power supply are described. For an H⁺ ion energy of 14 MeV, the unit provides a rectangular scanning raster with a linear size of ±300 μm on the target and a minimal point-to-point switch time of 200 μs. The positioning time does not exceed 40 μs.