强流溅射源负离子出束实验研究

在离子源实验台架上，利用200型强流溅射离子源进行8种元素的负离子出束实验研究。这些负离子对应元素的电子亲合势大部分接近或小于零，负离子难以形成。实验中尝试使用不同的靶材料和辅助气体产生负离子，以提高负离子束的束流强度。     

A Monte Carlo computer code for evaluating energy loss of 10 keV to 10 MeV ions in amorphous silicon materials

The basic concepts of a computer simulation code for determining the energy loss of ions in the 10 keV to 10 MeV energy range in amorphous silicon materials were presented and discussed. Data obtained were found in good agreement with those obtained by using a SRIM programme. Electronic and nuclear energy losses were evaluated. Variation of the energy loss as a function of the incident ion energy were studied. This new computer code is a good tool for evaluating stopping powers of various materials for light and heavy ions.     

某型虚拟冲击器的设计及数值模拟

虚拟冲击器能够吸入空气中的气溶胶并收集特定粒径的颗粒。一般来说,常用的虚拟冲击器的切割粒径较大,工作流量也较大,对于某些限制流量的工况可能不适用。在本研究中,开发了一种新型多缝虚拟冲击器,且喷嘴附近注入清洁空气,能够减小气溶胶在冲击器内的损失。通过数值模拟的方法分析该虚拟冲击器的性能,结果表明,即使总流量为36 L/min,也能获得0.08 atm的低压降,利用具有清洁空气的狭缝喷嘴虚拟冲击器,可将切割粒径降到0.2~0.4 μm,并以1.8 L/min的流量收集起来。     

微流体惯性冲击器过滤性能模拟计算

用微流体惯性冲击器收集μm尺寸气溶胶颗粒是一种新型的过滤方式,弥补了现有过滤收集方式的不足,已有学者进行了可行性论证,但气流在现有的T型惯性冲击器内压力损失较大且冲击器的加工工艺较为繁琐。本文设计并研究了一种新型微流体惯性冲击器,采用CFD软件对微流体惯性冲击器的过滤性能进行了数值模拟。建立了数学模型,对气相采用层流模型,对颗粒相采用离散相模型(DPM)。通过模拟计算,分析了不同尺寸的微流体惯性冲击器对粒子收集效率的影响。结果表明,冲击器转折角和尺寸D对收集效率均有较大影响:转折角越小,收集效率越高;当D≤1/2时,效率曲线基本不变。     

A conceptual design of light ion beam fusion reactor—UTLIF(1)

UTLIF(1) is a conceptual design study on a light ion beam driven fusion reactor based on a concept of pin-bundle blanket. The study includes nuclear and structural analyses of the blanket, consideration on materials, tritium handling system and power conversion system designs, pellet and beam driver designs, and economic analysis of the plant. The pin-bundle blanket has been shown to be attractive for light ion beam fusion reactors. Some subjects to be developed have been pointed out from reactor engineering aspects.     

Calibration of Cascade Impactor by Two-Stage Method

A simple method of calibrating the cascade impactor has been developed by applying Hongo et al.'s two-stage method to evaluate the particle-size distribution. The constants ψ and σfor a function representing the impaction efficiency were determined for the UNICO cascade impactor, using the test particles produced by a spinning-disc aerosol generator. The values were ψ=0.35, σ=1.46, respectively.

The validity of the method for the UNICO cascade impactor was confirmed from microphotographic observation of a sample artificial aerosol containing different sizes of uranine methylene-blue particles. Both the mass median aerodynamic diameter and the geometric standard deviation obtained with the method agreed with the microphotographie measurements with relative errors not exceeding 10%.     

Unique capabilities of heavy ion elastic recoil detection with gas ionization detectors

Specific aspects of heavy ion elastic recoil detection (ERD) with gas ionization detectors have been studied using representative measurements. A particular strength of the technique is the detection and direct quantification of elements with atomic numbers in the range Z=2–8, which are often not accessible with other ion beam techniques. Within the wider spectrum of analytical techniques in materials science, heavy ion ERD has unique capabilities, when the particular problem requires in addition the analysis of heavy elements or hydrogen detection. Whenever only heavy element analysis or only hydrogen profiling is of interest, alternative techniques tend to be superior.     

PROTON ELASTIC SCATTERING ANALYSIS OF C,N AND O COMPOSITION IN MATERIALS

Proton elastic scattering at energies around 2.0 MeV was used to determine the concentration of oxygen in a Y-Ba-Cu-O compound, nitrogen in a TiN film on steel substrate, and carbon and oxygen in a thin Mylar film. Proton scattering from light elements in this energy range exhibits non-Rutherford scattering cross section, which is enhanced by a factor of 4 to 7 relative to the Rutherford scattering cross section. Thus the sensitivity for the light element detection is considerably larger than that obtained by He~+ ion scattering. Quantitative analysis by proton scattering is discussed and compared with other methods.     

Influence of external action and structural factors on radiation blistering

A survey of experimental results is presented, pertaining to radiation blistering of a considerable number of materials (stainless steels, alloys with high nickel content, alloys of refractory metals) under helium ion irradiation with energies of 20–100 keV under conditions corresponding to the plasma-wall interaction: bombardment at various angles of incidence and cyclic irradiation in a wide spectrum of ion incidence angles; influence of external action, including thermocycling; influence of preceding neutron and proton irradiation. It has been shown that external factors have a complex influence on blister parameters and erosion coefficients of materials. A study has been carried out on the influence of aluminium coatings, alloying additions, phase state of material and microstructure on the nature and degree of surface erosion. Complex influence of element and phase composition, as well as microstructural changes during heat treatment and welding on radiation erosion have been established.     

固体核径迹对绝缘材料抗反射性能的影响

用HI-13串列加速器提供的³²S离子对聚碳酸酯和CR-39进行了不同密度的辐照,经紫外灯敏化和氢氧化钠蚀刻,样品表面的潜径迹形成具有一定孔径和深度的纳米和微米孔。利用真空蒸发在样品表面镀上金属银和光学材料氟化镁,在可见光波段测量样品镀膜前后的反射率、透过率等光学参数。测量结果表明,固体核径迹技术和镀膜技术可使材料的反射率降低至未处理前的1%以下。     

复合无机离子交换材料及其在水体放射性Cs检测中的应用

离子交换法速度快、能与检测仪器联用,已逐渐成为水体中放射性Cs的主要富集方法。由于单一的离子交换材料无法兼顾抗辐照性、强选择性和高吸附速率等性能,因此研发兼顾各种性能的新型离子交换材料将成为提高水体中放射性Cs富集效率的关键。本文通过总结复合无机离子交换材料在水体放射性Cs富集分离方面的研究进展及相关应用,分析了各类复合无机离子交换材料的优缺点,并针对不同复合无机离子交换材料的制备提出了溶胶 凝胶、多孔支撑体和有机物黏接等改进方法。这为制备更高效的复合无机离子交换材料和提高放射性Cs检测的效率提供了参考,也为离子交换法在其他领域中的应用提供了新的思路。     

Charge ratio mass spectrometry of heavy elements

A simple method of stable element assay at the parts per billion level using a sequence of charge changes at MeV ion energies has been demonstrated. Isotopic ratios and abundances of platinum have been studied using this technique in nickel sulphide and copper samples. Silver isotopic distributions have also been investigated in a number of terrestrial and meteoritic materials. A similar charge changing sequence between electrostatic analyzers at keV ion energies was shown to reduce backgrounds for a mass independent search of fractionally charged particles.The methods described form the bases of a broad band mass spectroscopic system under development at IsoTrace.     

Ion beam induced luminescence of materials

Ion beam interactions with many insulating materials produces strong luminescence and this may be collected and analysed to gain information on the defect structures present. The use of light ions such as H⁺ and He⁺ with MeV energies allows penetration to a depth of several microns in most materials. The variation of ion species and energy allows precise control of ion-induced damage and ionisation within the material. This control of depth, ionisation, and damage can be superior to that of the traditional cathodo-luminescence technique and comparison with spectra from the two methods often yields differences in sensitivity to different emission bands and features.     

He离子辐照对PZT陶瓷和微驱动器力电耦合性能的影响

为研究He离子辐照效应对压电微驱动器的力电耦合性能的影响规律。本文开展了3种不同剂量的He离子辐照实验,结合纳米压痕实验和有限元模拟技术,对辐照前后的PZT材料进行各向异性弹性参数识别;利用电学测量仪测量材料的压电和介电参数,并通过数值模拟研究辐照效应对微驱动器电致变形响应和固有频率的影响。结果表明,随着辐照剂量的增加,PZT压电材料的弹性参数、压电参数和介电参数均发生一定量的衰减,衰减率分别小于10%、4.8%和16.6%;辐照效应下,微驱动器的最大电致输出位移的变化率不超过4.6%,最大拉应力的变化率不超过5.4%,驱动器的前五阶固有频率的变化率不超过1%。      

Off-line studies of the laser ionization of yttrium at the IGISOL facility

A laser ion source is under development at the IGISOL facility, Jyväskylä, in order to address deficiencies in the ion guide technique. The key elements of interest are those of a refractory nature, whose isotopes and isomers are widely studied using both laser spectroscopic and high precision mass measurement techniques. Yttrium has been the first element of choice for the new laser ion source. In this work, we present a new coupled dye-Ti:Sapphire laser scheme and give a detailed discussion of the results obtained from laser ionization of yttrium atoms produced in an ion guide via resistive heating of a filament. The importance of not only gas purity, but indeed the baseline vacuum pressure in the environment outside the ion guide is discussed in light of the fast gas phase chemistry seen in the yttrium system. A single laser shot model is introduced and is compared to the experimental data in order to extract the level of impurities within the gas cell.     

Measurement of He and H depth profiles in tungsten using ERDA with medium heavy ion beams

Elastic recoil detection analysis method (ERDA) with medium heavy analyzing ion beam and its application for the simultaneous measurement of light elements in a very heavy substrate is presented. The availability of cross section data and the method of cross section calculation for recoiled particles are discussed. Different ion species for analyzing beam are discussed with respect to the cross-section data availability, sensitivity of the method, and the depth resolution. Calculations of depth resolution for each element and maximum depth of analysis for tungsten substrate are presented. The influence of the detector geometry and multiple scattering effects on the depth resolution is discussed. An example spectrum measured on tungsten implanted with He seeded D plasma is shown.     

Transmitted ion energy loss distributions to detect cluster formation in silicon

The energy loss distribution of ions transmitted through a 5.7±0.2 μm thick Si crystal was measured and simulated with the Monte Carlo channeling simulation code FLUX. A general resemblance between the measured and simulated energy loss distributions was obtained after incorporation of an energy dependent energy loss in the simulation program. The energy loss calculations are used to investigate the feasibility to detect the presence of light element dopant clusters in a host crystal from the shape of the energy loss distribution, with transmission ion channeling. A curved crystal structure is used as a model for a region in the host crystal with clusters. The presence of the curvature does have a large influence on the transmitted energy distribution, which offers the possibility to determine the presence of dopant clusters in a host crystal with transmission ion channeling.     

Application of the thin layer activation technique to study surface erosion under high voltage electrical spark discharges

The thin layer activation technique using a heavy ion beam has been applied to measure the erosion loss of materials by electrical spark discharges with a discharge current in the mA range. Since the range of heavy ions such as ¹⁴N, ¹⁶O and ²⁰Ne, is about one order less than that of light ions such as p, d and α, the total activity can be generated within a narrow layer by activation with heavy ions. In the present work, a narrow layer of activity of ∼27 μm thickness was produced in copper-based materials by heavy ion induced nuclear reactions using 110 MeV ¹⁶O ions to measure the surface erosion in the range of hundreds of nanometers to few microns. The sensitivity can be enhanced to tens of nanometers using suitable heavy ions.     

A review of ion beam induced charge microscopy

Since its development in the early 1990’s, ion beam induced charge (IBIC) microscopy has found widespread applications in many microprobe laboratories for the analysis of microelectronic devices, dislocations, semiconductor radiation detectors, semi-insulating materials, high power transistors, charge-coupled arrays, solar cells, light emitting diodes, and in conjunction with Single Event Upset imaging. Several modalities of the techniques have been developed, such as lateral IBIC and time-resolved IBIC. The theoretical model of IBIC generation and collection has developed from a one-dimensional model of charge drift and diffusion to a detailed model of the motion of ion charge carriers in semiconductors and insulators. This paper reviews the current state-of-the-art of IBIC theory and applications.     

离子束介导外源DNA导入小麦后代变异系有关分析

离子束技术是一种有效的农作物诱变和介导转基因技术,本研究利用离子束介导转化选育到一批有价值的小麦变异材料.本文对变异材料的农艺性状、品质性状、种子醇溶蛋白图谱进行了深入分析.结果表明,变异材料的株高、主茎穗长、千粒重、叶片性状、蛋白质含量、湿面筋含量与对照相比都发生了明显的变化并达显著水平;变异材料种子醇溶蛋白谱带已发生了确切的变化,且某些材料已稳定,还有的材料醇溶蛋白谱带存在多态性,还在分离之中.研究结果表明离子束介导转基因技术可产生丰富的变异、创造新的种质资源,并为该技术在小麦育种上的应用提供理论依据.