100keV金属表面改性离子注入与混合两用机

叙述了１００ｋｅＶ金属表面改性离子注入与混合两用机的总体结构及各主要部件的技术参数。该机经过调试各项主要指标已达到设计要求，工作稳定可靠，已开始金属材料表面改性实验。     

两种气体离子源氮离子注入细菌的诱变效应比较

低能离子注入作为一种新的诱变育种手段已经得到广泛的应用.对考夫曼气体离子源和双潘宁气体离子源氮离子注入凝结芽孢杆菌的效果进行比较.经研究发现,在相同的引出电压下,考夫曼气体离子源注入的菌体到第三代的遗传稳定性要比双潘宁气体离子源注入的菌体高30%,但突变平均幅度要低2%,以此为依据可以根据不同诱变需要选择合适的离子源.     

钇离子注入不锈钢的抗腐蚀研究

叙述了在复旦大学加速器实验室３０ｋｅＶ同位素分离器上建立的一套离子注入装置。在该装置上已获得几十微安的Ｙ、Ｃｅ、Ｈｏ、Ｓｍ、Ｎｄ、Ｌａ、Ｙｂ等稀土离子束流。被离子注入的面积为φ２０ｍｍ，表面均匀性好于３％，并对Ｙ离子注入不锈钢以改善其抗腐蚀性能进行了初步研究。     

Structure and morphology of ion irradiated Au nanocrystals in SiO2

We have investigated the effect of ion irradiation on the structure and morphology of Au nanocrystals (NCs) fabricated by ion beam synthesis in a thin SiO₂ layer on a Si substrate. Extended X-ray absorption fine structure (EXAFS) spectroscopy measurements show a significant drop in the average Au–Au coordination, as well as a loss of medium and long range order with increasing irradiation dose. Small angle X-ray scattering (SAXS) measurements reveal a concomitant reduction in average NC size. These observations are a consequence of structural disorder and collisional mixing induced by the irradiation. The observed reduction in average Au–Au coordination by EXAFS differs significantly from that estimated from the average NC sizes evaluated using SAXS. This behavior can be explained by the dissolution of Au NCs into the SiO₂ matrix. A significant bond-length contraction indicates that part of this material forms small Au clusters (dimers, trimers, etc.) during irradiation that cannot be detected by SAXS. Combining the results from SAXS and EXAFS measurements, we estimate the volume fraction of such clusters.     

Use of a duoplasmatron ion source for negative ion generation

The use of electronegative species as primary ions considerably enhances the emission of positive secondary ions in SIMS. Considering furthermore that negative primary ions can be required due to instrumental configurations (e.g. the Cameca NanoSIMS 50 requires an opposite polarity of the primary and secondary ions), O⁻ ion bombardment is employed in SIMS analysis. These O⁻ ions are typically created in a duoplasmatron source, which suffers however from its low brightness and which is thus not suited for high resolution imaging applications. The development of new (electro)negative ion sources is thus necessary to optimize the analysis of electropositive elements in terms of lateral resolution and sensitivity.In this paper, we present the performance of a duoplasmatron ion source generating F⁻, Cl⁻, Br⁻ and I⁻ ion beams. In particular, we experimentally determine on a dedicated test bench the brightness of the source in the F⁻, Cl⁻, Br⁻ and I⁻ modes as a function of the gas pressure, the magnetic field strength and the arc current in the source. The obtained results are compared to the performances of the duoplasmatron in the standard O⁻ mode. In this context, a five times higher brightness was found for F⁻ (200 A/cm² sr) compared to the standard O⁻ (42 A/cm² sr).     

聚苯胺的离子注入掺杂研究

研究了聚苯胺的离子注入掺杂对导电性的影响。用红外和紫外谱法探讨了聚苯胺的氧化态，本征态和还原态经离子注入后，其结构可能发生的变化。结果表明，聚苯胺的三种态的离子注入均为还原过程。讨论了离子注入掺杂的导电机制。     

基于磁偏转的真空弧离子源成分诊断

采用磁偏转的方法,对金属氢化物电极真空弧离子源放电产生的等离子体进行了成分诊断。采用了Ti D2电极材料进行放电,测量了在30-80 A弧流情况下的各离子的组分。实验结果表明,弧流越大时等离子体的密度越大,在现有引出结构下,由于等离子体发射面的凹凸变化导致测得的离子信号出现双峰。通过增加栅网可以减少等离子密度,双峰情况会有所减少。另外,随着弧流增大,氘所占比例会有所增加,弧流达到60 A以上氘含量增幅不明显。     

慢正电子束研究N^＋注入金属镍中生成的缺陷

用慢正电子束配合多普勒湮没能谱测量技术研究N~+离子注入镍样品产生的缺陷。由未注入的样品得到了正电子在镍中的扩散参数E_0=4.6keV。比较两个样品的S参数随入射正电子能量变化的曲线给出了95keV、6.4×10~(17)/cm~2剂量的N~+注入镍样品所产生的缺陷分布;缺陷由表面一直延伸到190nm,浓度最大的区域在27—110nm。这些都与由Trim程序的Monte Carlo模拟计算的结果很好地符合。     

铬,钽离子束表面冶金合金的抗腐蚀机制

根据离子束表面冶金的特点，从合金成分、结构、缺陷、元素性质以及表面污染等方面系统地讨论了Ｃｒ、Ｔａ元素加入对金属腐蚀行为的影响。在此基础上，提出它们抑制腐蚀的综合模式，较好地解释了这类表面合金抗腐蚀的机制。     

离子注入技术在植物育种中的应用与研究进展

离子束作为一种新的诱变源,具有突变谱广、突变率高、生理损伤小的特点,并且具有一定的重复性和方向性.文章阐述了离子注入的特点、诱变机理和诱变效应,综述了诱变育种取得的进展,展望了离子注入技术的应用前景.     

Nanopatterning of silica with mask-assisted ion implantation

In the present paper we combined ion implantation and nanosphere lithography to regularly dope, by a mask-assisted process, a SiO₂ substrate with rare earth ions (Er) by ion implantation and to fabricate by sputtering a plasmonic 2D periodic array of Au nanostructures on the silica surface spatially coupled to the implanted Er³⁺ ions. The aim of this work is to study how Er³⁺ emission at 1.5 μm can be affected by the interaction with a plasmonic nanostructure. In particular we have found a variation of the radiative lifetime of the Er³⁺ emission and a change from single exponential to bi-exponential of the luminescence intensity decay.     

Photoluminescence from neodymium silicide thin films formed by MEVVA ion source

Neodymium silicides were synthesized by Nd ion implanted into Si substrates with the aid of a metal vapor vacuum are(MEVVA)ion source.The blender of Nd5Si4 and NdSi2 was formed in a neodymium-implanted silicon thin film during the as-implanted state,but there was only single neodymium silicide compound in the post-annealed state,and the phase changed from NdSi2 to Nd5Si4 with increasing annealing temperature.The blue-violet luminescence excited by ultra-viloet was observed at the room temperature(RT),and the intensity of photoluminescence(PL)increased with increasing the neodymium ion fluence,Moreover,the photoluminescence was closely dependent on the temperature of rapid thermal annealing(RTA),A mechanism of photoluminescence was discussed.     

Oxygen ion source with plasma cathode

An ion source with a plasma cathode has been developed for long lifetime use in ion implanters. In this ion source, a plasma cathode replaces the conventional metallic filament used in a Freeman-type ion source. This ion source consists of two compartments, namely a plasma generator and an ion source chambers interconnected by a tapered narrow duct. The pressure difference between the two parts, maintained by differential pumping, prevents the feed gas from flowing into the plasma generator. With any combination of an argon plasma cathode and a feed gas of either fluoride (AsF₅, PF₅) or oxygen, the lifetime was found to be more than 90 h with an extraction voltage of 40 kV and a correspoding ion current density of 20 mA/cm², and a considerable amount of As⁺, P⁺, O⁺, and O₂⁺ ions were observed in mass spectra.     

Cosmic ion bombardment of the icy moons of Jupiter

A large number of experiments have been performed in many laboratories in the world with the aim to investigate the physico-chemical effects induced by fast ions irradiating astrophysical relevant materials. The laboratory in Catania (Italy) has given a contribution to some experimental works. In this paper I review the results of two class of experiments performed by the Catania group, namely implantation of reactive (H⁺, C⁺, N⁺, O⁺ and S⁺) ions in ices and the ion irradiation induced synthesis of molecules at the interface between water ice and carbonaceous or sulfurous solid materials. The results, discussed in the light of some questions concerning the surfaces of the Galilean moons, contribute to understand whether minor molecular species (CO₂, SO₂, H₂SO₄, etc.) observed on those objects are endogenic i.e. native from the satellite or are produced by exogenic processes, such as ion implantation.The results indicate that:

-

C-ion implantation is not the dominant formation mechanism of CO₂ on Europa, Ganimede and Callisto.

-

Implantation of sulfur ions into water ice produces hydrated sulfuric acid with high efficiency such to give a very important contribution to the sulfur cycle on the surface of Europa and other satellites.

-

Implantation of protons into carbon dioxide produces some species containing the projectile (H₂CO₃, and O-H in poly-water).

-

Implantation of protons into sulfur dioxide produces SO₃, polymers, and O₃ but not H-S bonds.

-

Water ice has been deposited on refractory carbonaceous materials: a general finding is the formation of a noteworthy quantity of CO₂. We suggest that this is the primary mechanism to explain the presence of carbon dioxide on the surfaces of the Galilean satellites.

-

Water ice has been deposited on refractory sulfurous materials originating from SO₂ or H₂S irradiation. No evidence for an efficient synthesis of SO₂ has been found.

     

离子注入甜菜杂交种当代生物效应

以甜菜杂交种为处理材料 ,用N+作为诱变源 ,以 35keV的能量 ,分别以 4 0次、6 0次脉冲 ,注入剂量分别为 4× 10 16 N+/cm2 和 6× 10 16 N+/cm2 进行激发诱变。结果显示 ,甜菜杂交种的产量、含糖率均有明显的提高。     

碳团簇Cn+(n=1-5)注入CR39树脂的吸收光谱研究

利用2×1.7串列加速器产生的团簇离子Cn+(n=l-5)注入到CR39树脂中,树脂的光吸收性质因注入的团簇离子的剂量、剂量率以及团簇中所含原子的个数不同而有不同的变化.该项研究表明团簇与固体相互作用时团簇效应是通过电子阻止来体现的.     

Etching and structure transformations in uncured epoxy resin under rf-plasma and plasma immersion ion implantation

Uncured epoxy resin was spun onto silicon wafer and treated by plasma and plasma immersion ion implantation (PIII) by argon ions with energy up to 20 keV. Ellipsometry, FTIR spectroscopy and optical microscopy methods were used for analysis. The etching, carbonization, oxidation and crosslinking effects were observed. The curing reactions in modified epoxy resin are observed without a hardening agent. A model of structural transformations in epoxy resin under plasma and ion beam irradiation is proposed and discussed in relation to processes in a space environment.     

Fluorine ion transmission through thin biological samples

F^2 beam with 3MeV is used to irradiate thin biological samples(onion inner suface membrane and kidney bean coat)in the transmission measurement ,its current density is 400-800nA/cm^2,Results show that the onion samples can be broken up quickly under ion irradiating;as to kidney bean samples,about 60% of the implanted ions penetrate the samples,most of them lose part of their eneregy,fewer ions are found to be able to transmit through the sample without energy loss.SEM experiments are carried out to study sample‘s damage induced by the ions irradiation.