Study on charge equilibration time of highly charged ions in carbon foils

Charge state distribution of 0.8MeV/u uranium ions after transmission through a thin carbon foil has been studied. It is observed that the charge state distribution is equilibrated after the uranium ions have passed through a 15μg/cm^2 carbon foil. The equilibrated average charge state is 33.72 and the charge equilibration time of uranium ions in carbon foil is less than 5.4fs.     

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.     

RIBLL终端大面积中子探测器阵列研制方案的理论计算

介绍了一种用于丰中子核研究的RIBLL终端大面积中子探测器阵列的研制.利用Geant4软件包对该探测系统的中子探测效率、时间分辨和位置分布等进行了蒙特卡罗模拟,同时对探测器的cross?talk进行了研究.给出了探测器的设计方案.     

Configuration of the valence neutrons of 17B

The reaction cross section of 17B on 12C target at (43.7±2.4) MeV/u has been measured at the Radioactive Ion Beam Line in Lanzhou (RIBLL). The root-mean-square matter radius (Rrms) was deduced to be (2.92±0.10) fm, while the Rrms of the core and the valence neutron distribution are 2.28 fm and 5.98 fm respectively. Assuming a "core plus 2n" structure in 17B, the mixed configuration of (2s1/2) and (1d5/2) of the valence neutrons is studied and the s-wave spectroscopic factor is found to be (80±21)%.     

Study on charge equilibration time of highly charged ions in carbon foils

Charge state distribution of 0.8MeV/u uranium ions after transmission through a thin carbon foil has been studied. It is observed that the charge state distribution is equilibrated after the uranium ions have passed through a 15 $\mu $g/cm$^{2}$ carbon foil. The equilibrated average charge state is 33.72 and the charge equilibration time of uranium ions in carbon foil is less than 5.4fs.     

Property measurement of the CsI (Tl) crystal prepared at IMP

Large-sized CsI(T1) single crystals,～Φ100 mmx350 mm,have been grown successfully,and this CsI(Tl) coupled with PD has been successfully utilized at RIBLL (the Radioactive Ion Beam Line in Lanzhou)to measure the energy of heavy ions as a stopping detector.The performances of CsI(Tl) detector coupled with PD and APD have been tested and compared,including the temperature dependence of scintillating light yield.     

兰州放射性束流线上速度选择器的设计制造及初步调试

描述了一台在兰州放射性次级束流线(RIBLL)前端安装的速度选择器系统, 该系统由2个三组合四极透镜组和1个正交的电磁场组成, 将用于熔合蒸发余核的研究. 介绍了该设备的设计思路、基本参数和本底抑制能力、传输效率、角度接收度以及动量接收度的测量结果. 结果表明该系统达到设计要求, 进行适当改造后可用于Z≤110的超重核素的研究和中重核区滴线核的研究.