CAS-LIBB单粒子微束装置的微束入射点位置确定和系统定位精度研究

中国科学院离子束生物工程学重点实验室建成了一台单离子微束装置(CAS-LIBB)。CAS-LIBB装置由一台van de Graaff 静电加速器产生能量在2.0-3.0 MeV 的离子。该微束系统主要用于实施对生长在一种薄塑料膜上的细胞核的指定位置投射预定个数离子的技术。系统采用安装在束流末端的石英毛细玻璃管作为瞄准器来实现束流的微化并截取微束。细胞辐射实验中对细胞的识别和定位由一套计算机集成控制程序来完成。本文将从对微束的捕捉和定位（确定离子出口的准确位置），以及该微束系统的定位精度测量方面进行研究和讨论。当采用内径为5 μm,长度为980 μm的毛细管作瞄准器时，系统的定位精度为：91％的实验对象定位在距离预定位置2.4μm的范围内，98％的实验对象定位在距离预定位置3.6μm的范围内。     

基于球面弯晶聚焦结构的桌面型单能X射线源设计及实验EI北大核心CSCD

提出了一种采用球面弯晶聚焦结构获得高亮度桌面型单能X射线的方法。在子午方向利用晶体色散实现单能、在弧矢方向通过球面镜聚焦提高光强。理论建模和光学仿真评估了该结构的色散和聚焦性能,验证了球面弯晶聚焦结构相对于柱面弯晶在聚焦特性上的显著优势。针对Al靶Kα1线单能需求,设计和装调了基于低功率Al靶X射线管的单能装置,并实验验证了其性能。结果显示,当X射线管工作在7 W功率条件下,CCD曝光10 min,Al靶Kα1线全视场光谱的探测器计数大于2×105,能谱展宽约为0.592 eV;引入200μm限束光阑,能谱展宽进一步减小至0.493 eV,探测器计数约为2×104。研究结果证实了该装置可以有效获得高亮度Al靶Kα1谱线,也为精确测量光学器件和系统的光谱特性提供了一种新的获得高亮度单能X射线的技术途径。     

电阻环束流探测器的标定

 电阻环探测技术是一种成熟、实用的在线测试束流技术，它能给出束流的大小和束流质心的位置。在即将投入使用的20MeV直线感应加速器中，该技术将作为一种精确的束流诊断手段。为此设计了一套精密的束流模拟和电阻环标定装置，其束流位置的定位精度达到0.02mm，以之对精心设计的电阻环进行标定。标定的结果表明电阻环对束流质心位置的测试精度达到0.5mm，经标定后的束位置拟合值绝对误差不大于0.2mm。     

高灵敏度等时性回旋加速器束流相位测量系统

介绍了兰州重离子加速器（HIRFL）束流相位测量装置。该装置的研制基于双平衡混频原理，利用了高频信号混频滤波技术，具有较高的测量灵敏度。通过安装在加速器中的容性感应探针探测等时性回旋加速器束流相位历程，对于调束中获取等时场信息并对磁场进行优化,从而提高引出束流强度和束流品质是非常重要的。该装置通过等时场相位优化实验，检验了相位测量数据的可靠性，测量精度达到±0.5°。     

远程激光诱导击穿光谱技术进展

远程激光诱导击穿光谱技术(Remote LIBS)是一种利用高能激光和聚焦手段实现远距离分析物质元素组成的光谱探测技术,是远程探测的一种重要手段。本文对远程LIBS的三种探测方式(开放路径式、光纤光路式和便携式探针式)及相应的系统结构做了总结和分析。传统的开放路径式对激光器、光学系统和检测系统的性能和规格要求严格,一直是远程LIBS的研究热点;光纤光路LIBS优点主要体现在系统光学聚焦结构的简化和等离子体光的有效接收。本文综述了远程LIBS新技术的研究进展,着重分析了飞秒成丝远程LIBS技术及与Raman光谱探测相结合等远程LIBS新技术的特点和优势。新技术大大提高了探测距离,增强了物质识别能力,为扩大远程LIBS的应用做出巨大的贡献。同时,论文详细介绍了远程LIBS技术在深空探测、危害物质检测、工业冶金、文物检测修复等领域的研究现状和应用新进展。远程LIBS技术随着激光技术和光谱检测技术的发展以及对LIBS定标反演的研究,探测距离和应用范围不断扩大,检测精度和准确度也在提升。     

软X射线相位型聚焦波带片的研制

软X射线波带片是软X射线光学中聚焦、色散和成像的重要元件。以激光全息-离子束刻蚀技术制作金的振幅型软X射线聚焦波带片,以此为掩模,利用接触式同步辐射光刻和离子束刻蚀技术在聚酰亚胺衬底上,分别制作出了镍和锗的软X射线相位型聚焦波带片。     

FIB快速加工纳米孔点阵的新方法

纳米尺度的点阵在纳米器件和基础科学研究方面都具有非常重要的应用.目前普遍采用的聚焦离子束和电子束曝光技术可以很方便的在衬底上加工纳米量级的微细结构，但大面积的图形加工过程需要花费太多的机时.介绍一种利用设计图形BMP文件的像素点阵和实际加工区域之间的匹配关系，通过聚焦离子束加工获得所需要的纳米孔点阵的新方法.采用这种方法可以在短时间内获得大面积的纳米点阵结构. 关键词： 聚焦离子束 电子束曝光 纳米孔点阵     

BRISOL放射性核束鉴别装置的研制北大核心CSCD

中国原子能科学研究院已经建成一台"在线同位素分离器"(BRISOL),在线产生并分离出需要的放射性离子束用于天体物理、核结构和材料科学等研究。其中研制的放射性核束鉴别装置,用来测量并鉴别能量30～300 ke V、束流强度在10~4～10^(11)Particle/s放射性离子束(RIB)的种类。介绍了该装置的原理、组成及调试结果。该装置结构紧凑,可在有限空间内完成核素的积累、转运和能谱测量。该装置已经用于"在线同位素分离器"的在线调试,通过在线获取的射线能谱确认了产生的38K+放射性同位素并给出放射性束流的强度。     

半导体单光子雪崩光电二极管的封装发展

半导体单光子雪崩二极管可实现微弱信号的探测,在量子通讯、激光雷达和大气探测等领域具有重要应用。虽然半导体单光子雪崩二极管的性能主要取决于探测芯片设计、流片工艺和外围匹配电路的设计,但后续的封装技术对其探测性能也有重要的影响。聚焦多年来半导体单光子雪崩二极管的封装发展,简要介绍了相应封装形式和技术,以及封装对于雪崩二极管性能的影响,最后对半导体单光子雪崩二极管的封装发展前景做出了展望。     

相关光子定标的符合测量精度分析

采用355nm连续激光泵浦BBO晶体产生参量下转换效应,搭建了相关光子辐射定标实验装置,使用时间数字转换和时间幅度转换两种符合测量方法进行比对测量,定标了不同光子速率下雪崩光电二极管在737nm波段的探测效率,分析了在高光子计数率下死时间和后脉冲等因素对符合测量选取符合门宽和意外符合的影响,比较了不同光子计数速率的测量结果并分析符合测量的修正因素,修正后两种测量结果的相对偏差优于0.25%.采用时间间隔技术测量了不同光子计数率的后脉冲概率,为提高单光子探测器的计数精度和相关光子定标的精度提供依据.     

Elaborate calibration procedure for cell irradiation at the CAS-LIBB single-particle microbeam

Single-particle microbeam is uniquely capable of precisely delivering a preset number of charged particles to individual cells or sub-cellular targets to be determined in vitro. It is crucial to find a reference point that relates the microbeam's location to the microscope's plane, and align individual targets at this reference point for cell irradiation. To choose an appropriate reference point, an approach based on analysing the intensity distribution of fluorescence in a thin scintillator excited by traversing particles is newly developed using the CAS-LIBB single-particle microbeam,which features decisive physical signification and sufficient resolution. As its bonus, this on-line analysis provides precise and fast response to the determination of beam profile and potentially optimizes the microbeam quality by further adjusting hardware setup.     

单离子微束离子入射点定位

 为满足辐射实验的定位精确度要求,提出了一种对微束离子入射点进行捕捉和定位的方案。该方案根据离子束流轰击闪烁体能激发出光信号的特性,结合单离子微束装置的显微图像采集系统,通过对离子激发出的光斑进行图像采集分析实现了对离子入射点的定位。验证实验通过一种CR39膜记录离子辐射径迹, 采用的毛细玻璃管瞄准器内径为5 μm,长度为980 μm。实验得出了运用该方案进行入射点定位时装置的整体定位精度。     

5.5 MV静电加速器终端电压稳定系统

 采用对静电加速器终端电压的稳定性进行控制,以提高单离子束流品质。设计了陷波器、低通放大器、带通放大器、误差放大器等信号处理电路。陷波器为双T形结构,其中心频率为50 Hz,此频率用以滤除工频干扰。带通放大器的中心频率为35 Hz,带宽为60 Hz。误差放大器输出0～10 V的控制信号,控制电晕针放电电流。测试了单离子束能谱和束斑。结果表明：静电加速器终端电压稳定性得到明显改善,其不稳定性小于1%,提高了单离子束束流品质。     

Design of the IMP microbeam irradiation system for 100 MeV/u heavy ions

A state-of-the-art high energy heavy ion microbeam irradiation system is constructed at the Institute of Modern Physics of the Chinese Academy of Sciences. This microbeam system operates in both full current intensity mode and single ion mode. It delivers a predefined number of ions to pre-selected targets for research in biology and material science. The characteristic of this microbeam system is high energy and vertical irradiation. A quadrupole focusing system, in combination with a series of slits, has been designed to optimize the spatial resolution. A symmetrically achromatic system leads the beam downwards and serves simulta-neously as an energy analyzer. A high gradient quadrupole triplet finally focuses a C6+ ion beam to 1 μm in the vacuum chamber within the energy range from 10 MeV/u to 100 MeV/u. In this paper, the IMP microbeam system is described in detail. A systematic investigation of the ion beam optics of this microbeam system is presented together with the associated aberrations. Comparison is made between the IMP microbeam system and the other existing systems to further discuss the performance of this microbeam. Then the optimized initial beam parameters are given for high resolution and high hitting efficiency. At last, the experiment platform is briefly introduced.     

Design of the IMP microbeam irradiation system for 100 MeV/u heavy ions

A state-of-the-art high energy heavy ion microbeam irradiation system is constructed at the Institute of Modern Physics of the Chinese Academy of Sciences. This microbeam system operates in both full current intensity mode and single ion mode. It delivers a predefined number of ions to pre-selected targets for research in biology and material science. The characteristic of this microbeam system is high energy and vertical irradiation. A quadrupole focusing system, in combination with a series of slits, has been designed to optimize the spatial resolution. A symmetrically achromatic system leads the beam downwards and serves simultaneously as an energy analyzer. A high gradient quadrupole triplet finally focuses a C^6＋ ion beam to 1 μm in the vacuum chamber within the energy range from 10 MeV/u to 100 MeV/u. In this paper, the IMP microbeam system is described in detail. A systematic investigation of the ion beam optics of this microbeam system is presented together with the associated aberrations. Comparison is made between the IMP microbeam system and the other existing systems to further discuss the performance of this microbeam. Then the optimized initial beam parameters are given for high resolution and high hitting efficiency. At last, the experiment platform is briefly introduced.     

Sensitive analysis of metal cations in positive ion mode electrospray ionization mass spectrometry using commercial chelating agents and cationic ion-pairing reagents

Metals play a very important role in many scientific and environmental fields, and thus their detection and analysis is of great necessity. A simple and very sensitive method has been developed herein for the detection of metals in positive ion mode ESI-MS. Metal ions are positively charged, and as such they can potentially be detected in positive ion mode ESI-MS; however, their small mass-to-charge (m/z) ratio makes them fall in the low-mass region of the mass spectrum, which has the largest background noise. Therefore, their detection can become extremely difficult. A better and well-known way to detect metals by ESI-MS is by chelating them with complexation agents. In this study eleven different metals, Fe(II), Fe(III), Mg(II), Cu(II), Ru(III), Co(II), Ca(II), Ni(II), Mn(II), Sn(II), and Ag(I), were paired with two commercially available chelating agents: ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedisuccinic acid (EDDS). Since negative ion mode ESI-MS has many disadvantages compared to positive ion mode ESI-MS, it would be very beneficial if these negatively charged complex ions could be detected in the positive mode. Such a method is described in this paper and it is shown to achieve much lower sensitivities. Each of the negatively charged metal complexes is paired with six cationic ion-pairing reagents. The new positively charged ternary complexes are then analyzed by ESI-MS in the positive single ion monitoring (SIM) and single reaction monitoring (SRM) modes. The results clearly revealed that the presence of the cationic reagents significantly improved the sensitivity for these analytes, often by several orders of magnitude. This novel method developed herein for the detection of metals improved the limits of detection (LODs) significantly when compared to negative ion mode ESI-MS and shows great potential in future trace studies of these and many other species.     

离子微束技术及其多学科应用

通过微米孔准直或电磁聚焦技术可将加速器产生的MeV离子束形成微米尺寸的离子束斑(微束), 从而用来研究固体和生物样品的微米空间分辨的材料信息和辐照响应。 结合MeV离子微束的发展历史综述了微束技术和跨学科应用, 包括利用微束开展具有空间分辨的离子束分析、 单粒子效应、 微纳加工和细胞辐射响应等研究。 介绍了中国科学院近代物理研究所的高能重离子微束辐照装置, 该装置成功地将总能量为1 GeV的C离子在大气中聚焦为1 μm×2 μm的微米束斑。 Beam of MeV ions from particle accelerators can be confined by collimators or focused by electrical/magnetic quadruples into micrometer size, and this microbeam can be used to obtain spatial information or radiation effect in solids and biological samples. This paper reviews the technical developments and the multi disciplinary applications of microbeam, including ion beam analysis, single event effect in semiconductor devices, proton beam writing and cellular response to targeted particle irradiations. Finally, the high energy heavy ion microbeam facility at the Institute of Modern Physics of Chinese Academy of Sciences is introduced, which has successfully focused 1 GeV Carbon ions into a beam spot of 1 μm×2 μm in air.     

Study of the aberrations of the IMP heavy ion microbeam irradiation system

A high energy heavy ion microbeam irradiation system is constructed at the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS). A quadrupole focusing system, in combination with a series of slits, has been designed here. The IMP microbeam system is described in detail. The     

Study of the aberrations of the IMP heavy ion microbeam irradiation system

A high energy heavy ion microbeam irradiation system is constructed at the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS). A quadrupole focusing system, in combination with a series of slits, has been designed here. The IMP microbeam system is described in detail. The intrinsic and parasitic aberrations associated with the magnets are simulated. The ion beam optics of this microbeam system is investigated systematically. Then the optimized initial beam parameters are given for high spatial resolution and high hitting rates.     

重离子微束单粒子翻转与单粒子烧毁效应数值模拟

用束径0.4μm的微束重离子数值模拟了单粒子翻转SEU和单粒子烧毁效应SEB.单粒子翻转给出了不同离子注入后漏区的电压(电流)随时间变化规律;计算了CMOSSRAM电路的单粒子翻转;给出了收集电荷随LET值的变化曲线并给出了某一结构器件的临界电荷;VDMOS器件单粒子烧毁给出了不同时刻沿离子径迹场强、电位线、电流和碰撞离化率的变化.