Ar16+和Ar17+离子与Zr作用产生的X射线谱

将超导离子源提供的10—20keV/q Ar¹⁶⁺和Ar¹⁷⁺离子入射到Zr金属表面，在相互作用中产生的X射线谱表明，高电荷态Ar¹⁶⁺离子在金属表面中性化过程中有可能存在多电子激发，使Ar¹⁶⁺的K壳层电子被激发形成空穴，在退激过程中发射特征Kα-X射线.空心原子Ar的K层发射X射线强度随入射离子的动能而减弱，靶原子Zr的L壳层发射X射线强度随入射离子动能的增加而增强.Ar¹⁷⁺的单离子的Kα-     

Arq+入射金表面激发靶原子Mα-X射线的动能和势能的阈值

在兰州重离子加速器国家实验室 用动能150 keV和1.2 MeV的Ar^q+束流分别入射Au表面, 测量了离子与表面相互作用过程中辐射的X射线谱. 结果表明, 多电荷态Ar^q+激发Au原子的M_α-X射线至少需要2 keV的势能. 本文采用半经典两体碰撞近似, 估算了炮弹离子通过碰撞激发靶原子辐射X射线的动能阈值.     

Ar+, He+，S+离子轰击n-InP单晶表面的机理研究

通过X射线光电子能谱和低能电子衍射实验研究了10～180 eV的Ar⁺、 He⁺、S⁺离子轰击n-InP(100)表面, 发现S⁺离子轰击可以产生In-S组分,减轻离子轰击对表面的物理损伤.对于Ar⁺离子轰击后的表面,经过S⁺离子处理和加热过程以后,表面损伤得到了修复,最终得到了2×2的InP表面,进一步验证了S⁺离子对InP表面的修复作用.     

极板电压与间距对大气压射频氩等离子体放电参数的影响

 基于1维流体力学模型,对大气压射频裸露金属电极氩气放电过程进行了研究。模型中考虑了氩等离子体放电过程中主要发生的激发和电离等7个反应过程,对等离子体反应产生的主要粒子,包括电子、氩原子离子Ar⁺、氩分子离子Ar2⁺和氩激发态Ar^*等,建立连续性方程、动量方程和电流平衡方程。分析了极板电压、极板间距对上述粒子数密度分布的影响。给出了电子,Ar⁺,Ar^*和Ar₂⁺密度随极板电压及间距变化的时空演化过程。得出极板电压或极板间距的改变会使放电空间的电场发生改变,对应一定的极板间距,极板电压有一个最佳值,极板电压和间距的变化会使对应的极板间有一个最佳电场值,而对应最佳电场有一个等离子体气体间最佳反应系数,从而使放电空间粒子数密度发生改变。     

相对论效应对类锂离子能级结构及辐射跃迁性质的影响

利用基于多组态Dirac-Hartree-Fock(MCDHF) 理论方法的相对论原子结构计算程序包GRASP2K, 细致计算了中性锂原子、类锂Be⁺, C³⁺, O⁵⁺, Ne⁷⁺, Ar¹⁵⁺, Fe²³⁺, Mo³⁹⁺, W⁷¹⁺及U^{89 +} 离子基组态及较低的激发组态1s²nl (n = 2---4, l =s,p,d,f) 的精细结构能级, 以及各能级间发生电偶极(E1) 自发辐射跃迁的能量、概率及振子强度. 同时, 在非相对论极限下, 计算了其相关原子参数. 通过对相对论及非相对论计算结果的比较, 系统研究了相对论效应对类锂等电子系列离子能级结构及E1跃迁性质的影响, 揭示了随原子核电荷数Z变化时, 跃迁能、振子强度强烈依赖于量子数n, l, j变化的规律; 同时, 目前的计算结果与其他已有的理论计算及实验测量结果进行了比较.     

不同波长激光辐照对痢疾杆菌生物学效应的影响

分别采用功率密度为1.7W/cm²、照射剂量为2000J/cm²的Ar⁺激光与LD激光辐照高耐药性的志贺氏福氏痢疾杆菌,波长较短的Ar⁺激光(488nm)所引起细菌的致死率与药敏实变率明显高于波长较长的LD激光(808nm),即波长较短的Ar⁺激光的辐照导致细菌耐药性显著降低.     

2s1/2—1d3/2壳层原子核能谱的壳模型分析

本文对2s_1/2-1d_3/2壳层原子核(A=30—40)能谱作了系统分析,计算仅限于由2s_1/2和1d_3/2支壳层产生的情态,但考虑了它们之间的全部组态混合效应。计算是采用多粒子壳模型的Talmi方法,将二体矩阵元当作参数,其值由实验确定。文中详细分析了Si³⁰,Si³¹,P³⁰,P³¹,P³²,S³²,Ar³⁷,Ar³⁸,K³⁸等原子核能谱,理论与实验符合颇好。     

基于RIBLL的核谱学实验研究方法

在兰州近代物理研究所放射性束流线(RIBLL)装置上开展了对极短寿命的远离核的核谱学实验研究.利用能量为69MeV/u的³⁶Ar¹⁷⁺轰击厚度为92.3mg/cm²的^natNi靶,以弹核碎裂方式产生目标核²⁹S.通过RIBLL的分离将它注入到Si(Au)带电粒子探测器中并测量其β延发质子能谱.所得到的²⁹S的β延发质子能谱和寿命与文献值符合得相当一致,证明了本实验所采用的技术路线是可行的.     

离子辐照石墨生成的纳米尺寸Ar泡

用60keV的Ni⁺和Ar⁺在相同实验条件下,先后分别辐照同一块石墨靶,剂量均为10¹⁸/cm².带能量色散X射线分析和电子衍射分析的高分辨透射电子显微镜观察和分析发现,尺寸不同的纳米Ar泡嵌在类玻璃碳薄片中,部分泡内的Ar可能已形成固体结构.     

高离化态硫离子光谱的理论分析

 在考虑组态相互作用的基础上,利用包含相对论修正的Hartree-Fock(HFR)理论对S⁸⁺-S¹³⁺离子的谱线波长及加权振子强度等有关原子参数进行了系统计算,并与最新的实验观测和其它理论计算结果进行了比较。计算结果表明：S⁸⁺-S¹¹⁺的各个原子态在LS耦合下纯度很高,随着离化度的增大,S¹²⁺和S¹³⁺离子的部分原子态能级出现混合,组态相互作用逐渐增强。通过对实验结果的分析,识别出32条实验谱线,其中大多数谱线来自S⁸⁺-S¹³⁺离子的2s²2p^k-2s2p^k+1和2s2p^k+1-2s2p^k+2(k=0,1,2,3,4)之间的跃迁,理论计算结果与实验谱线波长之间的绝对误差大多数都在实验的有效分辨力以内。     

高电荷态ECR离子源——LECR3

研制成功了一台新的高电荷态ECR离子源,该离子源主要为原子物理实验提供各种高电荷态离子束流,是基于中国科学院近代物理研究所14.5GHz高电荷态ECR离子源设计建成的,同时在该离子源中应用多种有利于提高束流强度的技术,设计时考虑到采用双频加热,试图通过试验双频加热模式来提高高电荷态离子的产额,并设计建造了一套束流聚焦分析系统,以提高电荷态分辨率和束流传输效率.     

CEA/Saclay的ECR轻离子离子源

In the beginning of the 90s,T.Taylor and his collaborators demonstrated ECR sources operating at low frequency(i.e.2.45GHz)are able to produce very intense single charge light ion beams. At CEA/Saclay,the SILHI source developments started in 1995.Since 1997 more than 100mA proton or deuteron beams are routinely produced in pulsed or continuous mode.To comply with ADS reliability constraint,important improvements have been performed to increase the installation reliability.Moreover,to optimize the beam transport in the low energy beam line,the extraction system was carefully designed and space charge compensation studies were undertaken.An important step has been reached in 2005 with the development of a permanent magnet source able to produce a total beam of 109mA at 85kV. A new test bench named BETSI,especially dedicated to permanent magnet source developments,is presently under construction.It will allow analysing positive or negative extracted beams up to 50keV and 100mA. In addition,for several years work has been done to optimize the production of negative hydrogen ion beam with such an ECR source.Recent analysis pushed towards the construction of a new set up based on a multicusp magnetic configuration. After a brief overview of the CEA/Saclay source developments,this article will point out on the recent results and present status.     

高电荷态ECR离子源引出束流4D 发射度测量仪设计

为了进一步探究高电荷态电子回旋共振(ECR) 离子源引出束流品质和横向相空间耦合情况,根据中国科学院近代物理研究所高电荷态离子源引出束流发射度测量需求,针对束流流强为1 eμA∼1 emA,能量范围为10∼35 keV/q 的直流或脉冲高电荷态重离子束,设计了一台实时四维Pepper-pot 发射度测量仪。该Pepper-pot 型发射度测量仪具有响应时间快和工作范围宽等特点。针对强流重离子束诊断的特点,在结构与材料选择上做了设计与优化,并对获得图像的处理方法提出了具体的解决办法。For the purpose of on-line beam quality diagnostics and transverse emittance coupling investigation of the ion beams delivered by an Electron Cyclotron Resonance (ECR) ion source, a real-time 4D Pepper Pot type emittance scanner is under development at IMP(Institute of Moden Physics, Chinese Academy of Sciences). The high charge state ECR ion source at IMP could produce CW or pulsed heavy ion beam intensities in the range of 1 eμA∼1 emA with the kinetic energy of 10∼35 keV/q, which needs the design of the Pepper Pot scanner to be optimized accordingly. The Pepper Pot scanner has many features, such as very short response time and wide dynamic working range that the device could be applied. Since intense heavy ion beam bombardment is expected for this device, the structure and the material selection for the device is specially considered during the design, and a feasible solution to analyze the pictures acquired after the data acquisition is also made.     

首次使用核反应法鉴别JUNA深地加速器A/q=2的束流种类

JUNA团队计划利用CJPL所提供的极低本底条件和400 kV高压平台上2.45 GHz ECR离子源产生的毫安量级束流首次在天体物理能区对关键核反应进行直接测量。实验需要10 emA的质子束流和He+束流以及2 emA的He2+束流。使用2.45 GHz离子源产生毫安量级的He2+束流是离子源制造的难点。由于离子源分析磁铁分辨能力有限,无法区分He2+和H+₂离子,本文首次使用核反应法对离子源产生的A/q=2的束流进行了鉴别,结果显示,JUNA项目2.45 GHz ECR离子源无法产生毫安量级的He2+束流。该研究成果为JUNA项目离子源的设计提供了重要的参考依据。JUNA团队另外研制了一台微波频率为14.5 GHz的ECR离子源并成功产生2 emA的He2+束流来满足实验需求。     

单粒子态ECR离子源

介绍了一台2.45GHz电子回旋共振(ECR)单电荷离子源的磁场场形,以及它和总束流的关系.并且比较了国际上现有的几台同类型离子源的磁场场形.由此得出了关于2.45GHzECR离子源磁场场形的一些结论.     

ORNL-HRIBF 6GHzECR离子源的最新结果

Experimental studies were conducted to characterize and improve the performance of the flat-B ECR ion source.The emittance of the source was investigated for the first time.The output beam currents of high-charge-states of Ar(q>8)were nearly doubled by increasing the plasma electrode aperture from 4mm to 6mm in diameter.To investigate possible enhancements with broadband microwave radiation,a"white"Gaussian noise generator was employed with a TWT amplifier to generate microwave radiation with a bandwidth of～200MHz.The performance of the flat-B ECR ion source was found to be much better with narrow bandwidth radiation when the source was operated in the flat-B region.However,the ion beam intensities and charge state distributions were improved with the broadband radiation when the source was tuned off the flat-B region.     

一台14.5GHz新型高磁场高电荷态ECR离子源

自行研制成功一台14.5GHz新型高磁场高电荷态电子回旋共振(ECR)离子源.描述了该离子源结构特点、参数优化及其磁场分布,并给出了调试测量结果.该离子源轴向磁镜场在轴线上的最高磁场可达1.5T,六极永磁体在弧腔内表面磁场可达1.0T.经初步调试,可得到0⁷+140eμA,Ar¹¹+185eμA,Xe²⁶⁺50eμA.所得结果与1998年国际上最好的ECR离子源进行了比较.     

不同磁路电子回旋共振离子源引出实验

空间推进所用的电子回旋共振离子源(ECRIS)应具有体积小、效率高的特点. 本文研究的ECRIS使用永磁体环产生磁场, 有效减小了体积, 该离子源利用微波在磁场中加热电子, 电子与中性气体发生电离碰撞产生等离子体. 磁场在微波加热电子的过程中起关键作用, 同时影响离子源内等离子体的约束和输运. 通过比较四种磁路结构离子源的离子电流引出特性来研究磁场对10 cm ECRIS性能的影响. 实验发现: 在使用氩气的条件下, 特定结构的离子源可引出160 mA的离子电流, 最高推进剂利用率达60%, 最小放电损耗为120 W·A^-1; 所有离子源均存在多个工作状态, 工作状态在微波功率、气体流量、引出电压变化时会发生突变. 离子源发生状态突变时的微波功率、气体流量的大小与离子源内磁体的位置有关. 通过比较不同离子源的引出离子束流、放电损耗、气体利用率、工作稳定性的差异, 归纳了磁场结构对此种ECRIS引出特性的影响规律, 分析了其中的机理. 实验结果表明: 保持输入微波功率、气体流量、引出电压不变时, 增大共振区的范围、减小共振区到栅极的距离, 离子源能引出更大的离子电流; 减小共振区到微波功率入口、气体入口的距离能降低维持离子源高状态所需的最小微波功率和最小气体流量, 提高气体利用率, 但会导致放电损耗增大. 研究结果有助于深化对此类离子源工作过程的认识, 为其设计和性能优化提供参考.     

宽带微波馈入对于具有常规磁场构型的ECR离子源性能的提高

As clearly demonstrated at several laboratories,the performances of electron-cyclotron resonance (ECR)ion sources can be enhanced by increasing the physical sizes(volumes)of embedded ECR zones.En- larged ECR zones have been achieved by engineering the central magnetic field region of these sources so they are uniformly-distributed"volumes"in resonance with single-frequency rf power.Alternatively,the number of ECR surfaces in conventional minimum-B geometry sources can be increased by heating their plasmas with multiple,discrete frequency microwave radiation.Broadband rf power offers a simple,low cost and arguably more effective means for increasing the physical sizes of the ECR zones within the latter source type.In this article,theoretical arguments are made in support of the volume effect and the charge-state enhancing ef- fects of broadband microwave radiation(bandwidth:200MHz)plasma heating are demonstrated by comparing the high-charge-states of Ar ion beams,produced by powering a conventional minimum-B geometry,6.4GHz ECR ion source,equipped with a biased disk,with those produced by conventional bandwidth(bandwidth:～1.5MHz)radiation.     

强流ECR离子源引出系统研究

为了提高强流ECR 离子源的引出束流品质,分别设计了1# 和2# 引出系统,利用束流引出模拟软件PBGUNS 对1# 和2# 引出系统进行了质子束流引出与传输的模拟计算,结合实际测得的发射度数据分析引出系统,发现2# 引出系统比1# 引出系统引出束流品质高。对ECR 离子源引出系统的电势等位线分布等参数引起的球差进行了简单数学推导及MATLAB 绘图,并结合1# 和2# 引出系统束流相图模拟结果证明了球差会使引出束流品质有效发射度增长,通过适当加大电极孔径可改善束流聚焦情况,得到了束流光学聚焦较好的束流引出系统设计。To improve the quality of extracted ion beam from a high current ECR ion source, 1# and 2# extraction systems were designed and tested. The PBGUNS code was used to simulate the 1# and 2# extraction systems of proton ion beam. The emittance measurement results with the two different extraction systems were compared and analyzed with the simulation, the conclusion that more high quality beam extracted from 2# system than 1# system was got. The formula derivation of ECR ion source extraction system spherical aberration and MATLAB drawing was done by the analyzing on the distribution of extraction field equipotentials, effective emittance increasing caused by spherical berration was proved by 1# and 2# extraction systems beam phase space simulation result, beam focusing would be improved if electrode hole size increasing appropriately and a general concept on good optics focusing of ion beam extraction system was proposed finally.