RIBLL束流诊断的发展

描述了重离子加速器放射性次级束流线束流诊断技术的新发展,它包括初级束流在线监测研制的非拦截式法拉第筒,监测低强度初级束流的塑料闪烁探测器,测量放射性次级束流剖面的大面积双维位置灵敏平行板雪崩室等.这些新研制的束流诊断装置的运用,明显提高了设置、调整、确定重离子加速器放射性次级束流线运行参数的速度和准确性,改善了放射性次级束流纯度和质量,并使得重离子加速器放射性次级束流线的运行更简洁、迅速和有效.     

γ射线和PET用晶体单元相互作用特性的研究

γ射线与晶体单元的相互作用特性对于PET探测器的研制有着重要的参考意义. 通过实验测得了不同能量的γ射线在BGO, CsI, NaI 3种闪烁晶体中的探测效率、 能量分辨率等相互作用特性参数, 并与蒙特卡洛模拟结果进行了比较. 结果给出了最适合PET探测器的晶体单元. It’s important for development of PET detector that the interaction effect of γ rays and scintillator units are studied. The detection efficiencies and energy resolutions of γ rays for BGO, CsI and NaI crystal detector units are measured. Geant4 Monte Carlo simulations are compared with the experimental results. The results of the best detection units for PET detector are presented.     

水分子在不同电荷态的重离子作用下的离化作用

运用含时密度泛函理论和局域密度近似方法,计算了水分子H2O在速度为12.5 a0/fs的重离子C+和C2+作用下产生的各种电荷态的水分子离子的几率,平均逃逸电子数和偶极矩的变化随时间的演化.计算结果表明,在重离子势最大时,电偶极矩的变化最大;重离子远离分子时,重离子的电荷态越高,产生高电荷态分子的几率反而越小.     

Topological structure of the solitons solution in SU（3） Dunne-Jackiw-Pi-Trugenberger model

By using C-mapping topological current theory and gauge potential decomposition, we discuss the self-dual equation and its solution in the SU（N） Dunne-Jackiw-Pi-Trugenberger model and obtain a new concrete self-dual equation with a δ function. For the SU（3） case, we obtain a new self-duality solution and find the relationship between the soliton solution and topological number which is determined by the Hopf index and Brouwer degree of C-mapping. In our solution, the flux of this soliton is naturally quantized.     

80MeV/u 20Ne轰击9Be碎裂产物反应总截面的测量

介绍了用透射法测量中能区²⁰Ne打⁹Be靶碎裂产生的次级束与Si靶作用的核反应总截面的方法,以及实验的探测器布局、实验过程和实验结果.并对理论上预言有奇异结构的核¹²N,¹⁷Ne和¹⁷F的实验结果与其相邻核进行了比较.     

Surface Plasmon—Assisted Excitation of Atomic Visible Light Spectral Lines in the Impact of Highly Charged Ions 126Xeq＋ on Solid Surfaces

We measured the visible light spectral lines of sputtering atoms from solid surfaces orAl, Ti, Ni, Ta and Au which are impacted by 150 keV 126Xeq (6 ≤q ≤ 30). It is found that intensities of the light spectral lines are greatly and suddenly enhanced when the charge state of the ion is raised up to a critical value. If assuming that potential energy released from the incident ion due to capturing one electron is enough to excite a surface plasmon, we can estimate the critical charge states and obtain the results very well consistent with the measurements for the above-mentioned target materials. This means that a surface plasmon induced by one electron capture can enhance the excitation of atomic visible light spectral lines in the impact of a highly charged ion on a solid surface.     

RIBLL传输效率研究

利用实验测量和Monte Carlo模拟的方法,研究了RIBLL的传输效率。分析了影响传输效率的主要因素, 发现碎片的动量分布形式对传输效率的模拟结果有重要的影响。 另外通过比较, 发现大部分碎片传输效率的模拟结果稍大于实验测量结果, 两者最大相差约几十倍, 这可以帮助估算次级束流强度, 指导实验设计。 he transmission of RIBLL has been studied by experimental measurement and Monte Carlo simulation methods. The analysis of influence factors of the simulated transmission has been accomplished, and it was found that the momentum distribution of fragments is one of the most important factors influencing the simulation results. Furthermore, through comparing the measured and simulated results, it is found that the simulated result is larger than the measured transmission for most fragments and the maximal difference between them is about several tens of times. This simulation is a good theory tools for estimating the intensity of the secondary beam and designing the experiment in the future.     

超重核研究谱仪的RFQ冷却聚束器RFQ1L

介绍了超重核研究谱仪中RFQ冷却聚束器RFQ1L的结构和运用SIMION程序对离子的冷却、聚束、引出和撇气过程的模拟情况。 模拟显示: 通过仔细选择工作点就完全可以把经过充气反冲质量分离器分离后的低品质束流转化为斑点小、发射度小和能量单一的高品质束流, 为紧接其后的磁铁和激光高效率分析提供条件。The structure and the simulation results about the cooling,bunching,extraction and skimming of the RFQ cooler and buncher RFQ1L, which is an important part of the being built super heavy nuclide research spectrometer, have been introduced. It shows that, by careful choice of its working point, we can obtain an ion beam with small beam spot, small emittance and mono energy, which can satisfy the requirements of the successive analyses by dipole and laser with high efficiencies.     

束流强度探测变压器

兰州重离子加速器冷却储存环工程 (HIRFL CSR)主环和实验环上带电粒子束流强度的测量和监视拟由环型束流变压器实现 .通过对各种磁芯性能的分析和比较 ,束流变压器磁芯材料最终采用环形高磁导率超微晶合金 ,可测量束流脉冲的频率范围为 0 .2 - 2MHz .选择低噪声放大器将感应信号适当放大 ,可以实现对最小流强为 1μA束流的测量. The intensity of a pulsed beam of charged particles in the Cooling Storage Ring Project of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR) will be measured with a toroidal current transformer. By comparing and analyzing the properties of kinds of magnetic cores, a strip wound toroidal core is adopted, which is made of a high-permeability alloy and can measure a pulsed beam with frequency range of 0.2 to 2 MHz. The permeability of Fe-based nanocrystalline alloy varying with frequency is measured...     

中能8B和9C与Si反应总截面的测量

能量为75MeV/u的¹²C初级束轰击2mm厚的初级Be靶,并利用RIBLL从弹核碎片中分离出54.2MeV/u质子滴线核束8B和61.1MeV/u的⁹C,再轰击Si靶,用透射法测量了它们与Si的反应总截面σ_R.并应用Glauber模型进行理论计算,分析结果表明⁸B和⁹C都可能具有质子晕结构.