AES and XPS studies of a por-Si/SnOx nanocomposite formed using a powerful ion beam of nanosecond duration

The results of the X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and scanning electron microscopy (SEM) investigations of tin-oxide nanolayers on samples of por-Si/SnO _x composites with varying matrix porosity, formed using a powerful ion beam of nanosecond duration, are presented. It is shown that rapid melting and crystallization of the surface leads to the formation of Si nanoparticles with a maximal size of 200 nm. It is established that tin is included in the structure of the nanocomposite in an oxidized state with a small inclusion of metallic β tin. With increasing porosity, the phase composition of the tin nanolayers becomes closer to the state corresponding to the highest tin oxide (SnO₂). It is also shown that, upon an increase in the porosity, the intensity of the tin 4d subvalent line increases, which is, apparently, associated with an enhanced degree of hybridization of tin and oxygen atoms. The changes in the elemental composition of the composite and the depth of tin penetration are estimated from the results of ion etching.     

Modification of carbon films by high-power proton-carbon ion beam of nanosecond duration

The effect of a high-power proton-carbon ion beam on the surface morphology and resistance of carbon films synthesized by plasma-enhanced chemical vapor deposition has been investigated. Possible mechanisms of the surface morphology changes and increase in the carbon film resistance due to irradiation have been discussed.     

Modification of polycrystalline SnO2 and ZnO under the action of a high-power ion beam of nanosecond duration

The modification of polycrystalline oxides (SnO₂ and ZnO) under the action of a nanosecond high-power ion beam (HPIB) with current densities of 50–150 A/cm², which is accompanied by melting of initial particles of the surface layer, is investigated. It is established that submicron-sized particles of tetragonal SnO whose average size is 210 nm are formed on the SnO₂ surface irradiated by an ion beam with a current density of 150 A/cm². These particles have pronounced crystallographic faceting. When ZnO is irradiated by HPIBs with different current densities, a thin Zn film is formed in the sintered surface layer. Possible mechanisms of the observed conversions are discussed.     

Erosion of solid surface under irradiation by high-power submicrosecond ion beams

The erosion of a solid surface under high-power pulsed ion beams is considered. The values of atom yield from an irradiated surface due to the evaporation are obtained by numerical simulation. The effect of beam parameters and target characteristics on atom emission intensity was investigated. The technological capabilities of high-power submicrosecond ion beams for solid surface etching are assessed.     

Structural and phase composition of fullerene films deposited by high-power ion beams

Deposition of carbon films containing C₆₀ and C₇₀ fullerenes is an urgent problem, related to development of nanotechnologies and new nanomaterials. Such films have been obtained by ultrafast deposition of dense ablation plasma on a substrate; the plasma was generated as a result of irradiation of a graphite target by pulsed high-power ion beams. The structural and phase composition of the deposited films has been investigated.     

Model of metal surface erosion under irradiation by high-power pulsed ion beams

The mechanisms of erosion of metal surfaces under the action of submicrosecond (10⁻⁹−10⁻⁶ s) ion beams in the power density range of P = 10⁶−10⁹ W/cm² with a particle energy of 1–2000 keV are considered. It is shown that the collective processes associated with the radiation heating of the surface are of great importance. A model for the erosion is proposed. In accordance with this model, the flow of atoms of the target leaving the surface being irradiated consists of two independent components caused by collisional sputtering and evaporation, respectively. The influence of the irradiation parameters on the erosion coefficient and the ratio between the sputtering and evaporation factors is analyzed.     

Nanostructuring in a system consisting of a thin metal film on a dielectric substrate under irradiation with a high-power ion beam of nanosecond duration

The formation of metal nanoparticles in a system containing a thin metal film on a dielectric substrate and irradiated with a high-power ion beam of nanosecond duration is studied. The nanoparticle formation mechanism is discussed.     

Formation of nanostructured carbon on steel targets irradiated by a high-power ion beam

The effect of the preliminary high-power ion beam treatment of steel targets (12KhN3A, St3, St20, St45) on the morphology and structure of a carbon layer produced by DC discharge plasma enhanced chemical vapor deposition using a C₂H₂/H₂ gas mixture has been investigated. It has been found that carbon nanotubes are formed on the St3 and St20 surface irradiated by the high-power ion beam with the ion current densities 50 and 100 A/cm².     

Diagnosis of high-power nanosecond pulses of microwaves

This article surveys methods for measuring the amplitude, time, energy, spectrum, and structure of the wave field of powerful nanosecond pulses of electromagnetic radiation obtained from relativistic microwave sources. Institute for High-Power Electronics, Siberian Division of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 98–109, December, 1996.     

Deposition of fullerene films from the ablation plasma generated by high-power ion beams on graphite targets

A possibility of deposing carbon films with a high content of C₆₀ and C₇₀ fullerenes from an ablation plasma generated as a result of irradiation of graphite targets by pulsed high-power ion beams is shown. The relative contents of the crystalline diamond-like carbon phase, crystalline fullerene phase, and amorphous carbon phase have been determined by X-ray diffraction analysis for different deposition conditions. The nanohardness and Young’s modulus of the deposited films and their adhesion to the single-crystal silicon substrate have been measured.     

Formation of hollow heavy ion beams in plasma lens

Hollow cylindrical high-energy heavy ion beams are an efficient driver for target irradiation to achieve highly compressed matter. This paper is devoted to the study of how hollow beams form with the use of a plasma lens. Calculations and measurements were performed with a 200 MeV/amu C⁺⁶ beam.     

Laser-triggered quasi-monoenergetic ion beams at a moderate intensity and pulse duration

Plasma produced by short laser pulses from thin homogeneous foils with light and heavy ions is capable of generating quasi-monoenergetic light ions. This happens for the tail of light ions near the front of heavy ions. It was found that this effect is well pronounced for a moderate laser intensity (～10¹⁸ W/cm²) and pulse duration (～1 ps) by using a 2D particle-in-cell simulation of the laser interaction with thin CD₂ foils. Quasi-monoenergetic deuterons form a jet from the rear side of the foil with the energy ～1 MeV. The conversion efficiency to these quasi-monoenergetic ions is 10^?3.     

叠片法测量“闪光二号”加速器的高功率离子束能谱

给出了利用叠片法测量“闪光二号”加速器高功率离子束能谱的基本原理及初步实验结果. 采用Ziegler的拟合公式编制程序计算了不同能量质子和碳离子穿过不同厚度Mylar膜后的能 量损失情况.在偏压法拉第筒阵列各个法拉第筒的准直孔前分别覆盖0—6μm厚的Mylar膜， 根据不同膜厚对应的信号衰减情况(叠片法)，得到了高功率离子束的离子能谱，离子的最高 能量>440keV，平均能量约为270keV，能量为200—300keV之间的离子数目最多，碳离子数和 90keV以下的质子所占总离子数的组分不多于32％.所测量离子能谱和离子数目随时间的分布 关系与二极管的电压和电流符合也较好.还将叠片法的测量结果与利用磁谱仪和采用飞行时 间法等的测量结果进行了比较，三种方法所得的测量结果基本一致. 关键词： 高功率离子束 离子能谱 法拉第筒 叠片法 能量损失     

Surface modification of bismuth and tin under the action of a powerful ion beam of nanosecond duration

Features of bismuth and tin sample morphology during irradiation by a powerful ion beam of nanosecond duration have been studied. It has been established that particles of various shapes are formed on the metal surface due to an increase in the bismuth melt volume during crystallization.     

Energy transmissivity of high-power nanosecond laser pulse focused on glass

The experimental results show that if the pulse energy is low, the damage does not occur and the corresponding transmissivity is 100%. But with the increase of the pulse energy, the damage occurs and the transmissivity decreases to between 100% and 50%, equal to 50% and lower than 50%.The concept of the cut-off time (T_cut) is proposed to give the physics explanation on it, and by taking the free electron density (FED) and the laser-induced damage threshold (LIDT), mathematical simulation of the change law of the T_cut and the corresponding energy transmissivity with the laser energy has been done, respectively. The analysis results indicate that the former definition method can predict all the situations successfully, but the second one cannot predict the situation of the transmissivity being between 100% and 50%, the reasons of this difference also be analyzed.