微波离子源聚焦离子束光学系统的研究

设计了一种微波离子源的聚焦离子束光学系统,分析计算了光学系统的束径。并数值模拟了由空间电荷作用造成的束径增宽效应,找出了影响束斑大小的主要因素和减小束径的方法。测试结果表明,在束能在２５ｋｅＶ时,束流为１４８ｎＡ,束径约为２０μｍ左右。     

Accurate location and marking of grain boundaries using focused ion and electron beams

We have investigated the 2×12° symmetric grain boundary of (0 0 1) oriented bicrystalline silicon substrates for high-T_c superconductor applications using scanning focused ion beam (FIB) and electron beam (SEM). We successfully used the focused ion beam to detect and to mark the grain boundary and hence, to increase the accuracy of positioning the Josephson device with respect to the grain boundary of the silicon substrate. Both imaging methods have been compared using channeling effects of focused ion and electron beams in a dual beam system.     

FIBSIM – dynamic Monte Carlo simulation of compositional and topography changes caused by focused ion beam milling

A new simulation program is presented for focused ion beam (FIB) induced sputtering in two-dimensional targets. The model combines dynamic Monte Carlo simulation of the collision cascades with cell-based topography simulation. This approach takes the nonlocal nature of the sputtering process into account, and treats doping, damage formation and compositional changes self-consistently with the evolution of the surface. Two applications are presented: erosion of a sample edge, and milling of a hole into a multilayer target.     

Dynamic binary collision simulation of focused ion beam milling of deep trenches

A new model is presented for the simulation of focused ion beam milling in two-dimensional targets. It combines dynamic Monte Carlo binary collision simulation with cell-based topography simulation, and includes relaxation of cell densities. In the Monte Carlo model advanced algorithms are used for surface treatment, trajectory termination, and collision partner selection. Cell relaxation is performed by minimization of an energy function written in terms of the grid point coordinates, taking the deviation of the cell area from its relaxed value into account, but neglecting viscous forces. Relaxation is limited to areas where nuclear collisions have occurred during cascade simulation. The code is applied to deep trench formation in Si targets by 50 keV Ga focused ion beams. The simulation results indicate the importance of material flow and compare well with experiments.     

离子注入与离子束混合两用机

早在1979年,为了解决应用于高温高真空环境下的轴承的自润滑问题,我们就着手采用     

Submicron-scale patterns on ferromagnetic–antiferromagnetic Fe/NiO layers by focused ion beam (FIB) milling

With the aim of studying the magnetic properties of reduced-dimensionality magnetic systems we have patterned 250 nm- and 500 nm-size square elements on Fe/NiO layers by 30 keV Ga⁺ focused ion beam (FIB) milling, varying beam current and pixel dwell time. By high resolution scanning electron microscope (SEM) imaging and atomic force microscopy (AFM) analysis we found that island size decreases from the nominal value by increasing the beam current and features sharpness improves on increasing the dwell time. The top surface of the isolated features has a pronounced edge bending which may be as high as 9 nm with respect to the flat inner area of the island and decreases as dwell time grows. By varying the ion fluence we found that such a shape is related to a surface swelling effect occurring at low ion fluence in the irradiated areas. The swelling-related damage at the edges is expected to influence the magnetic properties of the patterned features.     

重离子束辐照细胞研究的文献计量学分析

应用文献计量学方法和相应的应用软件,借助Web of Science平台对重离子束辐照细胞这一研究主题的相关文献、作者、期刊、机构以及关键词进行定量和系统考察。结果显示,重离子束辐照细胞研究在1990年之后日益活跃并深入;不同品质的重离子束辐照诱导不同类型细胞会产生不同的生物学效应、旁观者效应及其机制、重离子束辐照细胞生物学效应评估模型、重离子束治疗癌症过程中辐照品质选择与控制模型以及相应的计算机程序是该研究主题的重要内容;引入特定指数推测所得该研究主题重要学术期刊与Nature,Proceedings of the National Academy of Sciences of the United States of America,Cancer Research等期刊之间有较高的共被引频次,表明更多科学前沿的突破性成果和思路应用于该主题研究中;此外,该研究主要集中于少数国家、少数机构、少数作者,并且合作相对较少。     

低能离子注入过程中真空和注入对小麦过氧化物酶同工酶的影响

本文报道了真空处理和低能离子束注入处理对小麦过氧化物酶同工酶的影响。研究发现,经真空处理后的样品,其酶活随着培养时间的延长呈增加的趋势,与对照样保持一致;而且相同取样时间不同样品之间的酶活性随真空时间的延长呈现略为增加的趋势;各剂量的N^ 注入处理后,种子的发芽率未受影响,而剂量较大时种子的芽长增长速度受到了明显的抑制;低剂量处理能刺激过氧化物酶酶活升高,而较高剂量处理则使酶活降低。     

Focusing characteristics of the relativistic electron beam transmitting in ion channel

Based on the beam–plasma system model established in this paper, the trajectory of the electron beam in the ion channel is studied quantitatively through the envelope equation. Under different initial system parameters, the focusing transmission conditions of the beam in the ion channel are discussed. Then, a series of particle-in-cell simulations are performed, which generally versifies the theoretical results and shows some further details of the focusing behavior of the beam. It is found that the deceleration of some electrons around the focusing point or the beam–plasma interaction at the ion channel boundary will result in the generation of the residual electrons,which forms the electron return current that leads to the new instabilities influencing the focusing characteristics of the beam.     

离子束混合生成银-黄铜合金混层及其摩擦性能

黄铜是工业上应用十分广泛的一种合金材料,若能改善其表面的摩擦性能,又保持基体原有的强度,将是具有实际意义的。为此,我们用离子束混合技术将银引入黄铜基体,在表面生成了润滑性能良好的银-黄铜合金混层,并对其摩擦性能、强度及与基体的结合力作了对比试验,然后用AES、SIMS、SEM以及光学显微镜对其混合状态和表面形貌作了分析和     

Production of radioactive 9C ion beam and its optimization

1IntroductionCarbonionbeamhasattractedgrowinginterestintumortreatmentinthepastdecade.Thisisattrib-utedtoexcellentphysicalcharacteristicsofcarbonbeamlikedoselocalizationintheBraggpeakandhighrelativebiologicaleffectivenessoverthepeak.Toenhancetheefficacyofheavyionbeamsintreatingtumors,wehaveevenproposedanovelideausingdelayedβ-particledecaybeamssuchas9Cand8Bfortumortreatment.Theseradioactiveionscanisotropi-callyemitlowenergyα-particlesand/orprotonsaftertheir+β-decay.Besideslocalizingionsinbo…     

B-Ni、B-Fe系离子束混合实验研究

近年来,常用离子束混合法来研究二元金属系统的合金化问题。但是,在用离子束混合法研究类金属-金属二元系统结构变化方面,除掉Si与Pt、Pd等金属的单层膜反冲混合外,迄今还未见有研究资料发表。然而,类金属元素在金属的离子束表面改性中,以及在用其它方法形成非晶态等的研究中,是常用的元素。因此,研究类金属-金属在离子束作用下的结构变化具有现实意义。     

离子注入过程中拟南芥愈伤组织冻害的防护研究

以拟南芥愈伤组织为对象,探讨了 DMSO(二甲亚砜)处理和玻璃化处理两种方法对愈伤组织在注入过程中冻害的防护。结果表明,玻璃化处理较 DMSO 处理能更有效地对冻害进行防护,N+注入量增至200×2.6×1013cm? 时,仍有 60%左右的愈伤组织可以正常分化。此工作对于以活体材料为注入对象的研究有一定的实际意义。     

中国科学院物理研究所的离子束分析及离子注入改性研究

介绍了中国科学院物理研究所离子束研究室的主要设备、分析方法、离子注入材料改性研究以及近年来在半导体材料、高Ｔｃ超导材料、环保等领域中的研究工作。     

Sub-100 keV ion beam generation with a Van De Graaff accelerator using an external DC voltage supply

We present a method to produce stable proton and helium ion beams with energies of 10-100 keV from a 30-year-old Van De Graaff accelerator using an external stabilized DC voltage supply instead of the belt charging system. Requiring no other modifications, this makes an ideal system for ion irradiation with fluences up to 10¹⁵ ions/cm². Such ion energies and fluences are required in the emerging fields such as silicon micromachining using ion irradiation and we give examples of structures created with sizes as small as 200 nm.     

Nonplanar dust acoustic solitary and rogue waves in an ion beam plasma with superthermal electrons and ions

The propagation characteristics of dust acoustic solitary and rogue waves are investigated in an unmagnetized ion beam plasma with electrons and ions following kappa-type distribution in nonplanar geometry. The reductive perturbation method(RPM) is employed to derive the cylindrical/spherical Korteweg–de Vries(KdV) equation, which is further transformed into standard KdV equation by neglecting the geometrical effects. Using new stretching coordinates,nonlinear Schr?dinger equation(NLSE) has been derived from the standard KdV equation to study the different order rational solutions of dust acoustic rogue waves(DARWs). The impact of various physical parameters on the characteristics of dust acoustic solitary waves(DASWs) is elaborated specifically in nonplanar geometry. Further, the effects of ion beam and superthermality of electrons/ions on the characteristics of DARWs are studied. The results obtained in the present investigation may be useful in comprehending a variety of phenomena in Earth's magnetosphere polar cap region where the presence of positive ion beam has been detected and also in other regions of space/astrophysical environments where dust along with superthermal electrons and ions exists.     

75MeV/u￣(12)C离子Bragg曲线及黑色素瘤细胞失活的测量

用双电离室法测定了ＨＩＲＦＬ提供的７５ＭｅＶ／ｕ１２Ｃ离子经不同厚度降能片后的相对剂量，将降能片厚度等效为组织等效材料一水中的深度，得到了碳离子在水介质中的Ｂｒａｇｇ曲线，与计算的Ｂｒａｇｇ曲线进行了比较。同时测定了离子经不同厚度降能片后对黑色素瘤（Ｂ１６）细胞的失活效应，得到了离子束在不同贯穿深度上的Ｂ１６细胞存活数据。     

Mapping ion beam induced current changes in a commercial MOSFET

We demonstrate a novel nuclear microprobe imaging and analysis modality for micrometre-scale field effect transistor devices probed with focused beams of MeV ions. By recording the drain current as a function of time during ion irradiation it is possible to identify current transients induced by the passage of single ions through the sensitive structures of the device. This modality takes advantage of the fact that the ionization produced by the passage of a single ion acts in an equivalent way to a transient change in the gate bias which therefore modulates the drain current as a function of time. This differs from the traditional ion beam induced charge technique where the ionization drifts in an internal electric field and induces a single charge pulse in an electrode applied to the device. Instead a richer variety of phenomena are observed, with different time constants which depend on the proximity of the ion strike to the channel of the device. The signals may be used to examine device function, radiation sensitivity or to count ion impacts within the channel.     

碳离子辐照诱导的甜高梁花粉生活力及花粉母细胞减数分裂的研究

为研究重离子辐照突变株的细胞遗传学变化,以碳离子辐照选育出的甜高粱早熟突变株KFJT-1及其对照品种KFJT-CK为材料,比较研究了两者之间花粉生活力大小以及花粉母细胞减数分裂的差异。结果发现：KFJT-1的花粉生活力以及花粉总数大于KFJT-CK;KFJT-1花粉母细胞减数分裂大多进入第二次减数分裂时,KFJT-CK花粉母细胞集中在第一次减数分裂;在KFJT-1减数分裂末期II,出现了两组分裂时期不一致、3分体以及不均等分裂畸变状况,畸变率仅为4．5％,说明KFJT-1在生长繁殖过程中修复了大部分由于物理诱变造成的染色体畸变,且能稳定遗传。这些结果从生殖细胞水平进一步说明碳离子辐照早熟突变株KFJT-1较未突变株KFJT-CK成熟期早,且各项指标均优于KFJT-CK。