HIAF及CiADS项目进展与展望

强流重离子加速器（HIAF）及加速器驱动嬗变研究装置（CiADS）是"十二五"期间国家优先安排建设的16项中的重大科技基础设施。本文介绍了HIAF及CiADS项目意义、科学目标、装置构成及主要特点,对项目实施进展进行了阶段性总结,并对未来发展进行了展望。High Intensity heavy-ion Accelerator Facility (HIAF) and China initiative Accelerator Driven System (CiADS) are among 16 national research facilities built as a priority during China's Twelfth Five Year Plan. In this paper, the scientific feasibility, structures and the features of HIAF and CiADS are briefly summarized. Meanwhile, their present construction progresses are reported and their developments in the near future are outlined.     

HIAF电子冷却装置高精度线圈磁轴测量

强流重离子加速器装置（HIAF）将采用电子冷却技术,降低重离子束流的发射度和动量分散,提高核物理及原子物理实验的精度与亮度。电子冷却装置的冷却段磁场均匀度是影响冷却效率的主要参数,HIAF电子冷却装置采用多个独立高精度线圈串联产生纵向磁场的设计,获得极高的冷却段磁场均匀度。本文介绍了一种测量高精度线圈磁轴偏角的装置,采用定位装置测量线圈的几何对称轴,通过旋转霍尔探头测量线圈中心平面上的径向与轴向磁场分布,再根据磁场测量数据计算出线圈磁轴与几何对称轴之间的偏角。实际测量表明该装置的磁轴偏角测量精度达到±0.10 mrad。测量得到的HIAF电子冷却装置冷却段线圈样品的磁轴偏角为（1.28±0.10）mrad,达到设计要求。     

HIAF BRing及高能外靶实验终端的辐射屏蔽设计

强流重离子加速器（HIAF）是中国科学院近代物理研究所自主研制的一台高能强流重离子加速器,它可以实现p到U的全离子加速。为了保证HIAF运行时的辐射安全,针对该装置的增强器（BRing）及高能外靶实验终端,利用蒙特卡洛程序FLUKA及外推法计算得到了加速p,C及U三种离子时所需的辐射屏蔽。结果表明,加速质子时所需屏蔽厚度最大,并以此为依据给出了全地下结构的屏蔽设计。在此基础上,提出了一种估算高能质子/重离子加速器束流均匀损失时横向屏蔽厚度的方法。结果显示,估算结果与FLUKA计算结果符合较好,验证了该方法的有效性和准确性。High Intensity heavy-ion Accelerator Facility (HIAF) is designed by the Institute of Modern Physics, Chinese Academy of Sciences, which can accelerate particles from proton up to uranium. To guarantee the radiation safety of HIAF during operation, the FLUKA code and extrapolation method were adopted to calculate the shielding thickness. The calculations were based on proton, carbon and uranium particles when losing on the Booster Ring (BRing) and the high-energy experimental terminal. The results indicate that the shielding thickness required for accelerating protons was the largest. Basing on the results, a method for estimating the lateral shielding of a high-energy proton/heavy-ion accelerator was proposed. A good agreement shows between the estimated results and the FLUKA calculated results, the validity and accuracy of the method were verified.     

今日中国物理(五)

 1.朱伟等人提出 EMC效应新模型据《核所信息》报载,华东师大副教授朱伟,中科院上海原子核研究所助理研究员沈建国,研究员邱锡钧和中科院理论物理研究所研究员张肇西,从1983年开始,研究核子内的夸克分布,指出EMC效应(European Muon Collaborotion)涉及到两个不同层次的夸克概念:当人们论述束缚态核子内的夸克时,指的是组份夸克(或叫结构夸克);而论述深度非弹性散射过程中的夸克,则指流夸克.考虑到这两个不同概念之间的区别和联系,他们提出核内组份夸克模型的初步理论,预言核内海夸克不可能增强.其论文于1985年在荷兰《物理通讯》(Phys.Lett)发表.1986年BCDMS国际协作组在第24届国际高能物理会议上所公布的实验结果表明:EMC实验组的原始实验数据在小X(Bjorken光锥变量)区的上升是错误的.     

基于加速器的原子物理学

在简述基于加速器的原子物理学这门分支学科的形成过程和特点的基础上，介绍它的主要内容和最新成果。     

加速器质谱技术在核物理与天体物理中的应用

介绍了利用加速器质谱技术在核物理与核天体物理中的应用研究工作．包括放射性核素半衰期的测定、核反应截面的测量、超重元素的寻找、宇宙射线和太阳中微子性质等方面的研究工作.The application work which has been done and can be done in the nuclear physics and nuclear astrophysics using accelerator mass spectrometry is reviewed. The half-life measurement of long-lived radio isotopes, cross section measurement of nuclear reaction, searching for super heavy elements, cosmic study and solar neutrino detection are the main components which have been discussed     

First beams and experiments at the nuclotron

The new heavy ion superconducting synchrotron - Nuclotron was put into operation and the pilot physics results on relativistic nuclear collisions were obtained.     

HIAF上基于多核子转移反应的综合谱仪的机遇与挑战

丰中子核的结构及奇特衰变性质是核物理基础研究的一个重要课题。在即将开工的大科学工程强流重离子加速器装置（HIAF）上,我们将设计并建造一条专门针对多核子转移反应的综合谱仪。在此谱仪上,研究将主要集中于丰中子新核素的合成、鉴别及其核结构和衰变性质。介绍了此谱仪的动机、概念设计和工作原理,简要讨论了建造此谱仪的机遇和面对的困难。不同于熔合蒸发及弹核碎裂反应,多核子转移反应产物的出射在实验室系并不是0°附近的前冲方向,而是覆盖了25°~80°宽范围的圆锥角,这给收集和分离感兴趣的多核子转移反应产物带来了很大的困难。气体单元必须满足高束流强度、高传输效率、快传输速度的要求,其设计及建造具有挑战性。气体单元是该谱仪成败的最关键因素。The study on the nuclear structure and exotic decay property of neutron-rich nuclides is an important subject in nuclear physics research. In the ongoing big project HIAF (High Intensity heavy-ion Accelerator Facility), a general purpose spectrometer specific to the multinucleon transfer reactions is being designed and will be constructed. In this spectrometer, the researches will be concentrated on synthesis and identification of new neutron-rich nuclides, and on the study of their nuclear structure and decay properties. In this paper, the motivation, conceptual design and working principle of this spectrometer have been introduced, and the opportunities and challenges in the construction have been discussed briefly. Unlike the fusion evaporation and projectile fragmentation reaction products which are emitted in forward directions near 0° in laboratory frame, the outgoing angles of the products from multinucleon transfer reactions cover a wide range of 25° ~80°, thus it is very difficult to collect and separate those products of interest. The requirements of high beam rate, high transmission efficiency and high transport speed make the gas cell be very challenging in design and construction. The gas cell is the key component for the success of this spectrometer.     

HIAF高能辐照终端感生放射性

本工作是基于蒙特卡罗模拟软件FLUKA对高能强流重离子加速器（HIAF）高能辐照终端感生放射性进行初步研究。该终端可运行质子最高能量为9.3 GeV,最大流强是1.45×1012 pps（particle per second）。研究内容包括:（1）预测高能辐照终端内活化物质的放射性活度特性;（2）预测不同冷却时间高能辐照终端内残余剂量率分布。研究结果表明,HIAF正常运行时高能辐照终端内的感生放射性主要受束流垃圾桶活化产生的放射性核素影响。当加速器连续运行100天冷却4小时,垃圾桶表面残余剂量率为2.375 mSv·h-1。终端内空气中13N和15O动态饱和比浓度大于其对应的导出空气浓度。冷却水中13N和15O的活度大于对应的ALI_min。该研究是HIAF辐射防护基础研究以及加速器环境影响评价的一项重要内容。The Monte Carlo code FLUKA was used to predict the induced radioactivity of high-energy irradiation terminal of HIAF. The maximum energy of proton is 9.3 GeV, and the maximum current is 1.45×1012 pps (particle per second). In this study we were to predict:(1) the activity properties of activated substances in the experimental terminal; (2) the residual dose rate distribution in the experimental terminal at different cooling time. The results indicate that the induced radioactivity in the high energy irradiation terminal of the HIAF is mainly affected by the radionuclide induced in the beam dump. The residual dose rate on the surface of the beam dump is 2.375 mSv·h-1, after 100 d irradiation and 4 h cooling. The dynamic saturation ratio of 13N and 15O induced in the air inside the terminal is higher than its corresponding derived air concentration. The activity of 13 N and15O induced in cooling water is higher than its ALI_min. This study is a part of radiation protection basic research and environmental impact assessment for HIAF.     

南开大学奇异性核物理的理论研究

简要介绍了南开大学核物理组在奇异性核物理方面的理论研究工作. 已经完成的工作有核介质内超子平均自由程的理论计算, 奇异性核物理方面已完成的其他4个理论研究课题是, 不同重子杂质对原子核的影响、重味重子超核、核物质内的eta-介子以及K介子原子核的性质.     

放射性束装置给核结构研究带来的新机遇

利用放射性束装置所提供的高强度和高分辨率的短寿命核束流可达到核中质比的极端值 ,新的现象 ,如中子晕、质子晕、中子皮、质子皮、壳的减弱或消失 ,以及在滴线附近对力的重要性和核物质中质子 -中子对的新超导相的可能存在等不断涌现 .对这些现象进行研究和理解 ,然后回到实验上较易达到的稳定区核去检验人们的理解 ,会对进一步研究核结构、核合成、核天文和自然界基本对称性提供新的机遇 .By making use of the facility for radioactive beams which would be able to supply intense high resolution beams of short lived (radioactive) nuclei, the neutron proton ratio can be extended to extreme values, where some new phenomena such as neutron halo, proton halo, neutron skin, proton skin, growing evidence of the fragility or disappearance of shell structure far from stability, the importance of pairing correlation near drip line, and the possible existence of new superconducting phases of...     

High density matter at RHIC

QCD predicts a phase transition between hadronic matter and a quark-gluon plasma at high energy density. The relativistic heavy ion collider (RHIC) at Brookhaven National Laboratory is a new facility dedicated to the experimental study of matter under extreme conditions. Already the first round of experimental results at RHIC indicated that the conditions to create a new state of matter are indeed reached in the collisions of heavy nuclei. Studies of particle spectra and their correlations at low transverse momenta provide evidence of strong pressure gradients in the highly interacting dense medium and hint that we observe a system in thermal equilibrium. Recent runs with high statistics allow us to explore the regime of hard-scattering processes where the suppression of hadrons at large transverse momentum, and quenching of di-jets are observed thus providing further evidence for extreme high density matter created in collisions at RHIC.     

Fragmentation of relativistic gold nuclei in nuclear emulsion

Basic data are presented on the parameters of fragmentation, multiplicities and angular spectra of low energetic targed associated particles in the interction of ¹⁹⁷Au nuclei of 10.7A GeV.     

兰州重离子加速器冷却存储环控制系统

为了完成建设兰州重离子加速器冷却存储环,自主研发设计了其大型分布式控制系统。控制系统从功能上分为三层：业务管理层、前端控制层以及设备控制层。业务管理层主要包含控制管理程序、中心数据库以及同步时间系统;前端控制层主要包含前端服务器、前端控制器以及各其他控制器等;设备控制层主要为微控制单元 (MCU)多功能控制器以及被控设备等。其中中央数据库存储整个加速器的所有控制数据,为变能时控制系统的控制数据切换提供数据支持。从长期运行情况来看,控制系统需要进行相应的改进,但是能基本满足现行的实验需求。