Effective energy deposition and latent track formation of swift heavy ions in solids

In the present paper, latent track formation in yttrium iron garnet (YIG) produced by high energy Ar ions is briefly reported at first. Then, in the framework of thermal spike model, a phenomenological parameter describing the effective energy transfer from excited electrons to lattice atoms, effective energy deposition Qeff, is deduced. Qeff is a function of ion velocity, electronic energy loss (Se) and mean free path λ of excited electrons in the matter, and is a time moderate term initialized by Waligorski’s function of spatial energy deposition of secondary electrons ejected by incident ions. Size of ion latent track is proportional to Qeff value. From Qeff obtained by use of realistic λ values, the sizes of latent tracks in SiO2, YIG, Ti and Zr produced by given swift heavy ion irradiations are deduced and com- pared with experimental results. It is found that, from the fits to experimental results, the best λ values for SiO2, YIG, Ti and Zr are (6±1), (8±2), (6.1±1.0) and (9.6±1.0) nm, respectively. Moreover, the relationship between experimental damage and Qeff is discussed.

Electronic energy loss and ion velocity correlation effects in track production in swift-ion-irradiated LiNbO_(3):A quantitative assessment between structural damage morphology and energy deposition

The primary motivation for studying how irradiation modifies the structures and properties of solid materials involves the understanding of undesirable phenomena,including irradiation-induced degradation of components in nuclear reactors and space exploration,and beneficial applications,including material performance tailoring through ion beam modification and defect engineering.In this work,the formation mechanism of latent tracks with different damage morphologies in LiNbO_(3)crystals under 0.09-6.17 Me V/u ion irradiation with an electronic energy loss from 2.6-13.2 ke V/nm is analyzed by experimental characterizations and numerical calculations.Irradiation-induced damage is preliminarily evaluated via the prism coupling technique to analyze the correlation between the dark-mode spectra and energy loss profiles of irradiated regions.Under the irradiation conditions of different ion velocities and electronic energy losses,different damage morphologies,from individual spherical defects to discontinuous and continuous tracks,are experimentally characterized.During ion penetration process,the ion velocity determines the spatiotemporal distribution of deposited irradiation energy induced by electronic energy loss,meaning that the two essential factors including electronic energy loss and ion velocity coaffect the track damage.The inelastic thermal spike model is used to numerically calculate the spatiotemporal evolutions of energy deposition and the corresponding atomic temperature under different irradiation conditions,and a quantitative relationship is proposed by comparison with corresponding experimentally observed track damage morphologies.The obtained quantitative relationship between irradiation conditions and track damage provides deep insight and guidance for understanding the damage behavior of crystal materials in extreme radiation environments and selecting irradiation parameters,including ion species and energies,for ion beam technique application in atomic-level defect manipulation,material modification,and micro/nanofabrication.

快重离子电子能损引起的缺陷产生及其后续效应

快重离子与凝聚态物质相互作用是核物理研究的重要领域之一,近年不断有新的现象发现。文章综述了快重离子电子能损效应研究的历史和概况,重点介绍了快重离子辐照引起的缺陷产生和退火、潜径迹的形成、塑性形变、相变等现象以及相关理论模型,对该领域未来发展趋势给出展望。

电子能损的潜径迹形成机制及理论模型的新进展

潜径迹是荷能离子与固体相互作用的一个重要效应 ,可以借助化学蚀刻、电子显微镜、卢瑟福散射和其他方法所显现。通过研究依赖于离子能量和各种靶参数的径迹尺寸的变化可以获得关于微观机制的信息。本文概括地介绍了在电子能损体制下径迹形成的基本现象、观测技术以及所获得的重要的实验结果 。

高能Ar离子辐照聚酯薄膜潜径迹蚀刻

通过对０００ＭｅＶＡｒ离子辐照聚酯（ＰＥＴ）薄膜潜径迹蚀刻过程的研究，给出了表征ＰＥＴ聚合物材料特性的径迹可蚀刻性的能损阈值（ｄＥ／ｄＸ）ｃ，并通过不同方法讨论了ＰＥＴ膜的径迹蚀刻速度和体蚀刻速度。

Structural damage response of lanthanum and yttrium aluminate crystals to nuclear collisions and electronic excitation:Threshold assessment of irradiation damage

A comparative analysis is performed on the structural damage response and associated mechanisms in lanthanum aluminate and yttrium aluminate crystals under various irradiation conditions by a combination of experimental and theoretical approaches.Under low-energy Au~+irradiation,the damage accumulation curve shows a higher damage rate for LaAlO_(3)crystals than YAlO_(3)crystals.The relatively low irradiation tolerance of LaAlO_(3)to the action of nuclear collisions is ascribed to the large amorphization cross-section and effective cross-section for defect-stimulated amorphization.Under swift Ar^(12+),Ni^(19+)and Kr^(17+)irradiation with different ion energies and velocities,the formed highly-disordered/amorphous latent tracks with different morphologies in pristine and predamaged crystals are discussed,and the corresponding electronic energy loss and lattice temperature thresholds are quantitatively determined.Compared to YAlO_(3),LaAlO_(3)exhibits lower sensitivity and higher damage tolerance to the electronic energy loss process,attributing to its relatively high recrystallization efficiency during the rapid quenching process.Furthermore,the introduction of lattice defects into LaAlO_(3)and YAlO_(3)crystals considerably enhances the sensitivity and intensity of thermal spike response to the electronic energy loss,and the induced effective modification of track morphologies demonstrates the synergistic effect between the electronic energy loss and pre-existing defects created by nuclear collisions.In this case,even under the action of electronic energy loss below the threshold,the lattice temperature in the nuclear-collision damaged crystalline system could still meet the criterion for track production.The irradiation energy deposited to atoms and induced lattice temperature evolution discussed in this work provide a deeper insight into the complex processes involved in irradiation-induced latent track behaviors.

重离子生物效应研究中的一些基本物理问题

从原子物理学理论出发，论述了重带电粒子（重离子）与生物介质相互作用的某些物理过程，对重离子生物效应研究中主要涉及的一些基本物理问题进行了讨论．它们是：重离子的能量损失；δ电子的发射；电子输送和径迹晕（或阴影）；浓缩相效应和径迹芯．