Institutional Repository of Institute of Modern Physics, CAS
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X-ray spectrum emitted by the impact of Xe-129(q+) on Mo surface
No full textWe studied the characteristic X-ray spectra produced by the interaction of highly charged ions of X-129(q+) (q =25, 26, 27) with surface of metallic Mo. The experimental result shows that highly charged ions can excite the characteristic X-ray spectra of L-shell of Mo when the beam' s intensity is not more than 120 nA. The X-ray yield of single ion reaches a quantitative level of 10(-8) and increases with the increment of the ion' s kinetic energy and ionic charge (potential energy). By measuring the X-ray spectra of Mo-L alpha(1) the M-level lifetime of Mo atom is estimated by using Heisenberg uncertainty relation
Band properties of the transitional nucleus Pt-189
No full textHigh-spin states in Pt-189 have been studied with the in-beam gamma-spectroscopy method via the Yb-176(O-18, 5n) reaction at beam energies of 88 MeV and 95 MeV. A new level scheme of Pt-189 has been established. Rotational bands based on the upsilon i(13/2)(-1), upsilon f(5/2)(p(3/2)) and upsilon i(13/2)(-2)upsilon f(p(3/2)) configurations, as well as several structures with irregular level spacings, have been observed. Properties of rotational bands have been analyzed in the framework of triaxial particle-rotor model. A gamma similar to -30 degrees triaxial shape and a near prolate shape have been proposed to the upsilon i(13/2)(-1) and uf(5/2)(p(3/2)) bands, respectively. Two Delta I=2 transition sequences with similar energies have been observed, and they have been proposed to be associated with the upsilon i(13/2)(-1)upsilon f(5/2)(p(3/2)) configuration. According to the relevant Nilsson orbitals, the bands built on the upsilon i(13/2)(-1)upsilon f(5/2)(p(3/2)) configuration could be interpreted as a pair of pseudo-spin partner
Nucleon Superfluidity in Asymmetric Nuclear Matter and Neutron Star Matter
No full textWe have investigate the nucleon superfluidity in asymmetric nuclear matter and neutron star matter by using the Brueckner-Hartree-Fock approach and the BCS theory. We have predicted the isospin-asymmetry dependence of the nucleon superfluidity in asymmetric nuclear matter and discussed particularly the effect of microscopic three-body forces. It has been shown that the three-body force leads to a strong suppression of the proton S-1(0) superfluidity in beta -stable neutron star matter. Whereas the microscopic three-body force is found to enhance remarkably the (PF2)-P-3 neutron superfluidity in neutron star matter and neutron stars
Progress on the RFQ1L and LPT
No full textThe SHANS spectrometer is under construction in the Institute of Modern Physics, Chinese Academy of Science. The RFQ cooler and buncher RFQ1L is one of the key devices in the SHANS. To perform direct mass measurement, the Lanzhou Penning Trap LPT is also under construction. In this symposium, the principle of the SHANS, the status of RFQ1L and LPT and some primary test results will be reported
PROJECTILE FRAGMENTATION OF Ar-36,Ar-40 INDUCED REACTIONS
No full textFragment yields for Z >= 5 from projectile fragmentation using primary beams of Ar-36,Ar-40 at 50 MeV/nucleon on Ni-64 target have been measured in RIBLL fragment separator. We compare the fragment cross sections with the predictions of the empirical EPAX parametrization of fragmentation cross-sections and Statistical Abration-Ablation model (SAA) by considering the RIBLL separator transmission rate. Isotope yield ratios between these two reactions were calculated and isoscaling parameters alpha and beta are extracted, their dependences on fragment atomic number Z and neutron number N were presented
Design of a 7 T Superconducting Magnet for Lanzhou Penning Trap
No full textA penning trap system called LPT (LANZHOU PENNING TRAP) is now being developed for precise mass measurements in IMP (Institute of Modern Physics). The most key component of LPT is a superconducting magnet. A Phi 156 mm warm bore and two cylinder good field regions with a distance of 220 mm are required for trapping ions and measurements. As the required homogeneity is better than 0.5 ppm, several complicated coaxial coils are used to produce such a magnetic field. The size and position of these coils are optimized by using a method combining linear program with multiobjective optimization. Superconducting shim coils and passive shim pieces are used to eliminate inevitable winding tolerances and environmental influence. The fringe field is decreased to 5 Gs at 2 m line from the center of the magnet by active shielding coils. The designs of the mechanical structure, the quench protection system are also introduced in this paper
Development of the Super-FRS Superconducting Dipole Proto-type for FAIR Projects
No full text超级碎片分离装置Super-FRS（Super FRagment Separator）是德国GSI在建
的FAIR项目中的一个重要组成部分，它主要由前分离系统与主分离系统组成，束
流通过此装置被注入到低能、高能和加速环等三个区进行相应的科学实验研究。
在该装置上设计有24台二极超导磁铁，其样机由FAIR中国组负责研制。
二极磁铁作为加速器中的主要构成部件，起着偏转粒子的重要作用。磁铁
的工艺结构决定着磁场品质，而磁场品质的好坏又直接影响着束流的传输，为获
得可靠优质的束流，必须对磁体结构进行合理的设计。
本论文从磁场和超导的基本理论出发，根据 FAIR 工程部的总体要求，结合
国内外磁铁设计的经验，详细完整地介绍了 Super-FRS 大型高均匀度
Superferric二极磁铁样机的设计研制过程。文中重点讲述了磁铁的二维及三维
的磁场计算，冲片的结构设计，活极头的优化设计，整体叠压工艺的设计，加工
质量等铁芯的研制。另外也分别对超导线圈的结构及测试，磁场测量系统和一系
列配套系统等几个方面进行了详细讲述。
论文最后通过对磁铁各项性能的实际测量，分析得出磁场的测量结果与计
算结果非常吻合，精度达到了设计要求，其它性能指标也都能满足，证实该大型
超导二极磁铁的研制是成功的
Development of Quench Protection System of Super-FRS Superconducting Dipole Prototype
No full text本文首先通过对 Super-FRS超导磁铁样机的超导线圈的失超性能进行了分析计算，
确定出失超探测和保护系统的参数要求。
Super-FRS 超导二极磁铁样机具有较大的储能(0.5MJ)，采用主动保护方式将能量释
放到磁铁杜瓦外的保护电阻中。采用中心抽头不在一起的两组独立桥式电路进行失超探
测，以避免失超探测的死区。采用 NI PXI-7830R FPGA 模块对失超信号进行采集和处
理，并进行失超逻辑判断，给出失超触发信号。FPGA 模块可独立于操作系统运行，因
此该失超探测系统具有很高的实时性和可靠性。通过失超数据采集模块采集失超前后一
段时间的数据，便于离线失超分析。
通过测试，失超探测系统准确地检测到了超导磁铁失超的发生，失超保护电路在失
超触发信号作用下动作，有效地保护了磁铁
Study on the Influence of Heavy Ion Induced Bystander Effect on the Growth of Bystander Cells and Corresponding Action Mechanisms
No full text目的：
探讨辐射诱导的旁效应影响未受照细胞生长的规律及其作用的分子机制，解释各
种因素在细胞生长方面如何影响旁效应的表现。最后利用旁效应影响细胞生长规律的
假设对重离子辐照治癌中剂量优化进行预测。
材料与方法：
本论文采用中国科学院近代物理研究所兰州重离子研究装置(HIRFL/HIRFL-CSR)
产生的 12C6+离子束对人肝癌 HepG2 细胞进行辐照，以培养基介导法建立旁效应体系并
研究了受照细胞释放信号因子影响未受照细胞生长的规律。用蛋白质组学技术探索了
旁观者细胞蛋白质组图谱的变化并分析了旁效应对未受照细胞生长影响的分子机制。
结果与结论：
1、转移条件培养基建立的旁效应体系排除了受照细胞通过细胞间隙连接传递“信号因
子”给旁观者细胞的可能，但细胞间隙连接可能在旁观者细胞之间传递“信号因
子”和使“信号因子”级联放大方面发挥作用。
2、旁效应对未受照细胞生长的影响主要取决于“信号因子”的浓度。旁观者细胞的
生长与“信号因子”的浓度呈反向依赖的关系，照射强度与受照细胞的释放能力
也呈反向依赖关系。细胞凋亡和促进未凋亡细胞增殖的作用可能同时存在于旁观
者细胞中，两者的动态强度比影响旁观者细胞生长的表现。其分子机制可能与
MAPK信号途径对下游 HSP72 和 HSP27 的作用有关。
3、通过对旁效应“信号因子”作用特性的研究，可以缩小筛选“信号因子”的范围。
NO具有低浓度促进细胞生长，高浓度抑制细胞生长的特性，NO就有可能是旁效
应“信号因子”通路上的一环，与其它“信号因子”协同发挥作用。
4、本论文除了对辐照诱导旁效应的分子机制进行基础研究外，还有一个重要目的是为
重离子束治癌寻求最佳的治疗方案并设计科学合理的治疗计划提供旁效应影响的
理论基础。根据实验结果可以推测，在重离子治癌当中通过降低辐照剂量达到放
疗增敏的做法会使情况复杂化，重离子治癌中，应该利用重离子束在物理学及生
物学上表现出的特性提高单次辐照剂量、减少照射分次的策略以降低辐照诱导的
肿瘤细胞产生的旁效应。辐射治癌中能减小辐射诱导旁效应的影响可能是重离子
治癌的又一特点和优势
大功率开关电源叠层母排方法
No full text本发明涉及一种大功率开关电源B型叠层母排方法，即在大功率开关电源设计中，不用导线连接，而采用铜板连接，用铜板取代导线，铜板与铜板之间铜板之间都是相叠而安装的，完成了滤波电容，功率开关管或整流器多个器件的电气连接。本发明减小了开关柜的体积，又减少了内部连线，达到了抑制电磁干扰的目的