HIRFL–CSR电子冷却装置上的横向电子束温度

从磁场中单电子的轨道运动方程出发,分析并推出了HIRFL-CSR电子冷却装置上的横向电子束温度,并得到了一些重要结论.     

四例基于1,4-双(3-/4-吡啶基)-2,3-二氮杂-1,3-丁二烯的配位聚合物的组装和性质:金属离子对结构的影响

通过水热合成法,合成了4例由混合配体构筑的的过渡金属配位聚合物:{[Zn(4-bpdb)(pnba)₂]·4H₂O}_n(1),[Cd(4-bpdb)(pnba)₂]_n(2),{[Cd₂(3-bpdb)₂(OAc)₄]·5H₂O}_n(3),和{[Co(3-bpdb)(pnba)₂(H₂O)₂]·2H₂O}_n(4)(4-bpdb=1,4-双(4-吡啶基)-2,3-二氮杂-1,3-丁二烯,3-bpdb=1,4-双(3-吡啶基)-2,3-二氮杂-1,3-丁二烯,Hpnba=对硝基苯甲酸,HOAc=乙酸),并且分别用X-射线单晶衍射、元素分析、红外光谱、热差分析、X-射线粉末衍射表征了这4个配合物。晶体结构分析表明,配合物1显示出一维锯齿形链状结构,金属锌(Ⅱ)离子具有稍微变形的四面体配位几何构型。而配合物2和3却展现出一维梯状双链结构,镉(Ⅱ)离子展现出五角双锥几何构型。而配合物4却拥有一维直线型链状结构,其中钴(Ⅱ)离子拥有八面体几何形状。上述结果说明,金属离子的几何构型可能对配合物的结构具有重要的影响。此外,还研究了配合物1~3的荧光性质。     

辅助信息下的逆抽样设计算法

通过将逆抽样设计视为一种特殊的二重抽样,建立了二重抽样和为回归估计的二重抽样的一般形式,得到了逆抽样设计算法下的回归估计.模拟分析的结果表明,以回归估计的形式引入较为合适的辅助信息,能够在估计精度上对逆抽样设计算法做出改进.     

HIRFL-CSR complex

The construction and commissioning of HIRFL-CSR were finished in 2007. From 2000 to 2005 the subsystem and key devices of CSR were successfully fabricated, such as magnet, power supply, UHV system, e-cooler, electric-static deflector with the septum of 0.1 mm, and the fast-pulse kicker with the rise time of 150 ns. After that the CSR commissioning activities were performed in 2006 and 2007, including the accumulation of those heavy ions of C, Ar, Kr and Xe by the combination of stripping injection （STI） or multiple multi-turn injection （MMI） and e-cooling with a hollow e-beam, wide energy-range synchrotron ramping by changing the RF harmonic-number at mid-energy, the beam stacking in the experimental ring CSRe, the RIBs mass-measurement with the isochronous-mode in CSRe by using the time-of-flight method, and the ion beam slow-extraction from CSRm.     

Commissioning of electron cooling in CSRe

The 400 MeV/u 12C6＋ ion beam was successfully cooled by the intensive electron beam near 1 A in CSRe.The momentum cooling time was estimated near 15 s.The cooling force was measured in the cases of difierent electron beam profiles,and the difierent angles between the ion beam and electron beam.The lifetime of the ion beam in CSRe was over 80 h.The dispersion in the cooling section was confirmed as positive close to zero.The beam sizes before cooling and after cooling were measured by the moving screen.The beam diameter after cooling was about 1 mm.The bunch length was measured with the help of the signals from the beam position monitor.The difiusion was studied in the absence of the electron beam.     

大白话 科学化 专业化——基于儿童原始生活经验的物理教学设计策略

"大白话"来源于学生的生活,是儿童对生活的原始体验,起源于自身的感悟或道听途说;或来源于课堂中对现象观察,所获取的初步的感知、操作技能."大白话"在某种程度上阻碍了他们对物理的学习,特别是在八年级起始阶段的物理学习.他们在分析问题或解答物理问题时,大多数依赖的是这些源自于生活感受的原始"大白话"式的体验和思维方式,在他们来到课堂之前,不可能被我们洗成"空白"大脑.     

ADS注入器II的5 MeV高能传输线的设计与搭建

ADS先导专项的注入器Ⅱ计划在将质子束通过一个Cryomodule加速到5 MeV后,进行10 mA连续束流的调试,以验证ADS低能段的强流超导直线加速器技术。为了将50 kW的束流功率沉积到束流垃圾站,需要搭建一条高能束流传输线,从超导段开始传输束流。采用两套三组合四极透镜控制束流包络及垃圾站的束流尺寸,利用诊断真空室进行水平和垂直发射度的测量。为避免束流产生的真空管道损伤,该传输线必须确保束流无损失地传输到垃圾站。A CW 10 mA,5 MeV beam commissioning of CADS Injector Ⅱ is planed recently to test the high power superconduction linac techniques.To transport 50 kW beam from linac to the beam dump,a high energy beam line (HEBT) line is designed and setup.Two Triplet are used to control the beam size along HEBT and at the beam dump.One diagnostics box is used for horizontal and vertical emittance measurement.To avoid damages to the vacuum pipe,beam should be transported to the beam dump without losses.The details of the HEBT design will be described in the paper.     

全剥离离子94mRu44+的衰变研究

在兰州重离子加速器冷却储存环（HIRFL-CSR）上,用等时性质量谱仪首次研究了百微秒量级全剥离离子94mRu44+的衰变。94mRu44+由初级束流112Sn轰击Be靶产生,经过放射性束流线RIBLL2的筛选后注入到等时性设置的实验环CSRe中,并利用安装在实验环中的飞行时间探测器测量离子在CSRe中的循环周期。94mRu44+退激引起的质量改变会带来其循环周期的变化,由此直接观测到了94mRu44+退激到基态的过程。确定了本次实验中衰变事例探测的灵敏区间,并讨论了衰变发生时刻的测量精度。同时,测量了短寿命核素94mRu44+的质量,其半衰期约为100 μs,这是目前储存环质量谱仪测量的最短寿命核素的质量。The decay of the fully stripped ion 94mRu44+ in the order of one hundred microseconds has been studied for the first time by using the Isochronous Mass Spectrometry (IMS) at the HIRFL-CSR facility in Lanzhou. 94mRu44+ was produced via projectile fragmentation of a 112Sn primary beam bombarding on a 9Be production target. After the in-flight separation with RIBLL2, the ions were injected into the experimental ring (CSRe) and then stored there. The revolution times of the stored ions were measured by a Time-of-Flight (TOF) detector. Due to the mass change of a 94mRu44+ ion caused by its de-excitation to the ground state, hence the revolution time change, the decay process of 94mRu44+ could be directly observed in the CSRe. The sensitive window for detection of the decay events and the measurement precision of the decay time have been determined in this work. At the same time, we measured the mass of short-lived 94mRu44+ with the half-life about one hundred microseconds, which is the shortest among nuclides that have been studied by using storage-ring mass-spectrometry.     

SSC-LINAC重离子RFQ动力学模拟与研究

采用多粒子跟踪程序BEAMPATH 对SSC-LINAC 重离子RFQ 直线加速器进行动力学模拟,分别对RFQ 的接受度、高频特性、束流稳定性、空间电荷效应等进行了分析。该RFQ具有很大的纵向接受度,有利于束流在RFQ中的传输;高频特性研究表明,翼间电压设定在理论值以上时,该RFQ都能保持较好的束流特性;束流稳定性分析结果表明,该RFQ具有很大的束流失配容忍度;空间电荷效应研究表明,当束流强度低于0.5 mA时,束流传输不受影响。综合研究结果表明,53.667 MHz重离子RFQ具有较好的动力学特性,满足SSC-LINAC直线加速器的设计要求。The RFQ beam dynamics of a heavy ion linac was investigated in this paper and the BEAMPATH code was employed in this study. The main research was focused on the beam performances depending on longitudinal acceptance, RF properties, beam instability and space charge effect. The RFQ has large longitudinal acceptance in design, which brings the beam performances well. In the RF parameter study, the beam can keep good transmission in the acceleration even the vane voltage is larger than the theoretical value. It is also shown that the RFQ has a large robustness for the mismatch of the input beam by the analysis of the beam instability.Furthermore, the beam evolution is independent on the space charge effect when the beam current is less than 0.5 emA. The preliminary analysis of the beam dynamics shows that the 53.667 MHz heavy ion RFQ has a promising performance, which meets the requirements of SSC-LINAC.     

热屏位置对直拉硅单晶V/G、点缺陷和热应力影响的模拟

为了研究热屏位置对φ200 mm直拉硅单晶V/G、原生点缺陷浓度场以及热应力场的影响,使用CGSim有限元模拟软件进行了系统模拟.结果表明:热屏位置对硅单晶的V/G和原生点缺陷浓度的径向分布规律没有影响;较热屏至晶体侧表面距离相比,其底端至熔体表面距离的影响更大,即随着它的增加,V/G值沿径向普遍增大且由内向外变化程度增强,晶体心部高浓度空位区扩大,最大热应力减小.合理控制热屏底端至熔体表面的距离可有效改善晶体质量.