离子辐照单晶Si损伤效应的研究

回顾了低能离子注入单晶Si经由核弹性碰撞引起的损伤特征及其常规的研究方法,介绍了快重离子辐照单晶Si经由电子能损引起的损伤特点及研究现状,并对该领域的研究作了展望. The radiation damage in silicon induced by low energy ion implantation was briefly reviewed together with a short introduction to the common techniques in the area. The damage characteristics of swift heavy ion irradiation in silicon and its investigations were introduced with emphasis on the effects induced by processes of electronic energy losses. It is shown that swift heavy ion can induce defects far beyond the projected range and up to 28 MeV/μm the electronic energy ...     

129Xeq+轰击N型和P型Si表面时的电子发射产额研究

在兰州重离子加速器国家实验室测量了1.8 MeV Xeq+离子分别轰击N型和P型Si两种靶材表面时的电子发射产额。实验中,通过改变入射离子的电荷态,研究了入射离子势能沉积对两种靶材表面电子发射产额的贡献。结果发现同一离子入射时,N型Si表面的电子发射产额高出P型Si表面的电子发射产额约12.5%;对于具有相同入射动能的Xeq+离子,两种靶材表面的电子发射产额均随着入射离子势能的增加而线性增加。此外,还测量了3.4 MeV Xeq+离子分别轰击以上两种靶材时的电子发射产额,得到了类似的结果。本文利用功函数分别从动能电子发射和势能电子发射两个角度对实验结果进行了分析讨论。The electron emissions from N-type Si and P-type Si induced by 1.8 MeV 129Xeq+are measured in the National Laboratory of Heavy Ion Research Facility in Lanzhou,The contribution to electron emission yield from potential energy of incident ions is studied through changing the charge state of incident ions.The results show that for the same incident ion,electron emission yield of N type Si surface is higher than that of P-type Si surface about 12.5%.For incident ions with the same kinetic energy,both electron emission yields of two targets increase linearly with incident ion energy.In addition,the electron emissions induced by 3.4 MeV 129Xeq+from N-type Si and P-type Si mentioned above are measured,which give similar results.The experimental results are analyzed and discussed using work function from two angles of the kinetic electron emission and the potential energy electron emission.     

聚合物材料的快重离子辐照效应

简要介绍了快重离子辐照损伤的特点,通过与低电离辐射粒子辐照在聚合物材料中产生的效应的类比论述了快重离子辐照在聚合物材料中产生的效应及其研究现状 ,并结合快重离子辐照效应的应用展望了该领域未来的发展.The irradiation effects in polymers induced by swift heavy ions were reviewed in comparison with that induced by low ionization particles based on the characteristics of swift heavy ion irradiations. It is shown that bond breaking and cross linking, gas releasing, amorphization and carbonization of polymers depend strongly on the electronic energy loss. Besides special effects such as alkynes production, can be induced under swift heavy ion irradiation. The perspectives...     

纯金属中电子能损效应的实验研究

简要评述了快重离子辐照在纯金属中引起的电子能损效应的实验研究结果 ,特别是强电子能损在金属中引起的辐照缺陷的部分退火、新缺陷的产生 .离子潜径迹的形成和辐照相变等. As swift heavy ions are available for irradiation damage study, it has been tried to evidence whether electronic energy loss might play a role in the damage processes of metallic targets. Experimental investigations showed that, as increase of electronic energy loss, large amount of electronic energy loss can result in radiation annealing of part of defects produced by elastic collisions, defect creation, latent track formation, as well as phase transition, and so on. Pure metals...     

离子径迹模板法制备纳米线

重离子辐照的高分子有机膜,经过适当的处理,可以作为模板制备金属和可溶性盐纳米线,此方法称为离子径迹模板法。介绍了用电化学沉积方法和过饱和溶液法制备金属纳米线和可溶性盐纳米线的基本原理和制各实例,同时还展望了离子径迹模板法制备纳米线的一些可能的应用。The polymer foils irradiated by heavy ions can be used as temptates to prepai nanowires and some inorganic salt nanowires. It is called ＂ion-track template method＂. Compared to other templates, such as AAO template and porous silicon, etched ion-track template is more convenient and flexible. The density of the pores can be easily controlled by changing the ion fluences and the diameter of the pores can be altered through changing the etching condition. The pores of the etched ion-track template are well aligned. We present some examples of preparing metallic nanowires and inorganic salt wires by electrochemical deposition and by supersaturation solution method, respectively. We also introduce some applications of nanowires prepared with ion-track template method.     

快重离子在固体材料中的强电子激发效应

简要介绍了快重离子在固体材料中强电子激发效应的基本特点、研究现状和在HIRFL上获得的部分实验结果,并对今后的研究工作进行了展望。In this paper the outline of intense electronic excitation effects in solid materials induced by swift heavy ions and international research status were briefly reviewed. Few examples of experimental results obtained on HIRFL were presented. And also the developing tendency in the field was looked into the future.     

快重离子引起的塑性形变现象

非晶材料在快重离子轰击下显示了奇异的各向异性的塑性形变 ,这是电子能损所引起的宏观可见的剧烈的原子重排 .这个效应不能发生在具有晶态结构的材料中 ,但发生于所有的非晶材料中 .这一宏观现象隐含了寻找原子尺度上电子激发转换成原子位移的潜在线索 ,因而受到广泛的关注 .在回顾了现象发现的历史之后 ,综述了离子束引起的塑性形变的基本规律、最新结果、实验方法和技术新的进展 ,最后讨论了相关的物理机制和唯象模型. A very peculiar effect occurring when an amorphous material is irradiated with swift heavy ion is the giant plastic deformation phenomenon discovered in the eighties by Klaumunzer[DD(-8/9]¨ It is macroscopically visible atomic rearrangements induced by electronic energy loss. This effect occurs only in truly amorphous solids and can not occur in a crystalline material. This phenomenon gives rise to a wide ranging and lasting research in the field of the interaction of swift heavy...     

金属材料中高能重离子辐照效应的理论描述

简要介绍了高能重离子在金属材料中引起辐照效应的主要理论 ,特别是与电子能损引起的缺陷产生与演化、离子潜径迹形成、辐照相变以及各向异性塑性形变等效应相应的理论描述.Experimental results showed that, for high energy heavy ion irradiations, electronic energy loss could play a dominant role in damage process in solid materials. In order to explain the experimental phenomena and results, a series of theoretical models based on Coulomb explosion or thermal spike mechanisms have been proposed. In the present paper, more attention was paid to theoretical expressions of high energy heavy ion irradiation induced effects in metallic materials ...     

碳离子辐射诱导秀丽隐杆线虫生殖细胞凋亡研究

重离子辐射具有独特的深度剂量分布和较高的相对生物学效应,被认为是理想的放疗手段。重离子的生物学效应在径迹形成过程中由多个物理参量共同决定,而这些物理参量和离子入射深度紧密相关,因此明确离子不同入射深度的生物学效应对重离子肿瘤放疗方案的设计和优化有着重要的理论和应用价值。使用兰州重离子研究装置HIRFL-CSRe 终端的碳离子束作为辐射源,以活体模式动物线虫作为实验对象,以线虫生殖细胞的凋亡水平作为生物学检测终点,研究了10 和20 Gy 碳离子辐射在辐射的入口、坪区和峰区的当代生物学效应和对后代个体基因组不稳定性的影响。结果表明:10 和20 Gy 碳离子辐射在三个不同的辐照区域内均显著增加了辐射当代的线虫生殖腺细胞的凋亡水平,并表现出一定的辐射区域和辐射剂量依赖性。同时,辐射诱导的后代个体基因组不稳定性也表现出一定的辐射区域和辐射剂量相关性。Heavy ion irradiation is a perfect means in radio-therapy due to its special depth dose distribution and high relative biological effects. The biological effects of heavy ion irradiation are determined by some major physical parameters, and vary along the tracks of heavy ions. Therefore, it is very significant for the tumor radio-therapy to investigate the biological effects along whole range of heavy ion radiation. In the present study, Caenorhabditis elegans, a model in vivo, was irradiated by carbon ion beams from HCRFL-CSRe, The level of germ cell apoptosis of worms was used as a checking endpoint for DNA damage, the effects of carbon irradiation located in the entrance, plateau and peak regions on the genomic instability of the irradiated worm and their progeny were detected. The results showed that the 10 and 20 Gy of carbon ion radiations led to the increased germ cell apoptosis in irradiated worms and these effects depend on the worm location along the range of carbon ions and the irradiation dosage. The results also suggested that heavy ion irradiation induced the up-regulated genomic instability in their progeny, and might be related to both the irradiation dose and the irradiated location.     

固体材料中快重离子辐照损伤建立过程中的离子速度效应

快重离子辐照损伤建立过程中的离子速度效应是近年来才发现的,离子速度效应是指快重离子在固体材料中引起辐照损伤的损伤截面, 损伤效率和损伤形貌的离子速度相关性, 简要介绍了固体材料中快重离子辐照损伤建立过程中离子速度效应的发现、研究现状和主要实验结果, 并进行了尝试性评价.     

The temperature of the track

The energy deposition of swift charged particles penetrating solids is accompanied by such processes as particle (electron, atom, ion, molecular ion, photon …) emission and/or a change of the solid along the particle track. The energy, velocity and mass distribution of such secondary particles obtained from thin solids (such as carbon, polyhydrocarbon, isolators and conductors) penetrated by projectiles (e.g. Ar 1.8 MeV) was measured quantitatively. A number of direct and indirect production mechanisms contribute to the internal source of electrons and secondary ions. The analysis of the ejected radicals give information on the emission processes, the temperature, the charge and the time scale of energy deposition near the surface of the solid which, eventually, become responsible for the track formation.     

Latent track creation in fused silica by 200 MeV silver beam

Studies of formation of latent tracks in swift heavy ion irradiated SiO₂ are presented. Fused silica (SiO₂) were irradiated with 200 MeV silver (Ag) ion beam at varying fluences. Radiation-induced effects were studied by ultraviolet(UV)/Visible optical absorption spectroscopy and transmission electron microscopy (TEM). UV/Visible absorption study indicated E′ centers and oxygen deficiency centers having characteristic absorption occurred at 5 eV. The density of these color centers calculated from the absorption peak intensity showed Poisson-type variation with irradiation fluence. The defects are thus entirely confined to the latent tracks created by swift heavy ions in SiO₂. The track radius estimated from optical absorption study was found to be 5.1 nm. Similar results were obtained from TEM studies of the irradiated samples.     

高速H2+离子轰击C靶诱发二次电子的发射行为与入射角的关系

运用Monte-Carlo方法结合半经验理论研究了高速H2+离子轰击C靶诱发二次电子的发射行为与入射角的关系。分别研究了电子发射产额与入射角以及发射统计性与入射角的关系。结果表明，由于H2+上的价电子的影响使得背向电子发射产额不遵守余弦倒数关系。斜入射时候的前向与背向电子产额的比值跟正入射时的情况不同。电子的发射统计跟入射角没有关系。标志偏离Poission分布的值 b，随入射能量的增加而增大。     

Effects of swift heavy ion-irradiation on mica- and coal-based rocks of Lower Himalayas in Sikkim,India

Naturally occurring mica schist and coal sedimentary sequence in Sikkimese Himalaya were collected and investigated by two micro-techniques: scanning electron microscopy/energy dispersive spectrometry and Raman spectroscopy. They were applied to identify the constituents and the structure of the minerals before and after swift heavy ion irradiation. Vibrational data and the constituents of abundantly found mica schist and coal-based rock were acquired at room temperature and were compared with those reported for their analogues in the previous reports.     

低速离子在固体中的电子阻止本领

本文介绍了低速离子在固体材料中电子阻止本领的理论发展情况。着重介绍了有效电荷理论和根据有效电荷理论,由氢离子在材料中的电子阻止截面标度各种重离子在同种材料中电子阻止截面的方法。 用电导理论导出了低速离子贯穿价电子气的阻止截面公式,并给出了一套有效电荷比的经验公式。利用这套公式求得的电子阻止截面Se的值,既符合实验上发现的Se随z_1或z_2振荡的规律,又符合Se随入射离子能量的变化关系。     

Differential and total ionization cross sections due to impact of swift heavy ions

In the present work, the Binary stopping power theory was used to calculate total ionization cross section and differential cross section for energy transfer from a swift heavy ion to the target electrons. The dependence on the projectile charge state is studied. The calculated values are compared with the experimental values collected from the literature.