Power Pulsed Ion Beam Research Articles

Study of the influence of a powerful pulsed ion beam on titanium deeply-doped with aluminum

The work studies the synergy effect of high-intensity implantation of aluminum ions and the subsequent impact of a powerful pulsed ion beam on the microstructure and properties of titanium. Specimens of titanium were implanted for 1 h at a temperature of 1170 K with an ion fluence of 1021 ions/cm2. Layers with a thickness of about 150 μm were obtained. The energy impact was carried out by a powerful nanosecond pulsed ion beams with an ion current density on the target of 100 A/cm2. The paper presents data on changes in the elemental composition, and microstructure of ion-doped and energy-modified layers. It has been established that the additional energy impact on the ion-doped layer of a powerful pulsed beam improves microstructure at depths of about 4.31 μm. The synergistic of high-intensity ion implantation of aluminum and the energy impact of a pulsed ion beam improves the wear resistance of titanium by eighteen folds.

Material Modification by Powerful Pulsed Ion Beams

Material Modification by Powerful Pulsed Ion Beams

Влияние мощного импульсного ионного пучка на топографию поверхности вольфрама

The tungsten surface was processed by high power pulsed ion beam at the TEMP accelerator (Cn+ ions, accelerating voltage 200 ± 10 kV, energy density of a single pulse 2.6 – 3.0 J/cm2). Changes in the relief and structure of the surface of tungsten samples were studied by scanning electron microscopy. After treatment with a powerful pulsed ion beam (MIIP), defects in the form of craters form on the surface of tungsten. The number of craters decreases with an increase in the number of impact pulses. After exposure to 3 pulses, microcraters are forms in the surface layer along the grain boundaries. After 10 pulses, there are practically no cracks on the irradiated surface. An increase in the number of pulses leads to the formation of a more equiaxed ultrafine-grained structure in the near-surface layer of tungsten.

Effect of high-power ion beams on the surface topography and structure of submicrocrystalline titanium alloy subsurface layers

The study covers the topography and structural phase state of VT1-0 and VT6 submicrocrystalline titanium alloy subsurface layers irradiated by high power pulsed carbon ion beams (ion energy is 250 keV, pulse duration is ~100 ns, pulse current density is 150–200 A/cm2; surface energy density of a single pulse is j ~ 3 J/cm2 when irradiating VT1-0 titanium alloy samples and j ~ 1 J/cm2 when processing VT6 titanium alloy samples; pulse number is 1, 5, 10, and 50). The surface of samples was subjected to preliminary mechanical grinding and polishing before irradiation. It was shown that surface defects are formed on the surface of the alloys after irradiation, namely craters of different shapes and geometries with a diameter from fractions of a micron to 80–100 μm. At the same time, the grain structure in the subsurface layer becomes more homogeneous in terms of grain size and equiaxial properties. The initial state of titanium alloys is characterized by a fairly homogeneous structure with an average grain size of ~0,31 μm for VT1-0 and ~0,9 μm for VT6. After one irradiation pulse, grain growth to 0,54 μm in the transverse direction is observed in the subsurface layer of the VT1-0 alloy (j ~ 3 J/cm2), while grain size decreases to ~ 0,54 μm in the VT6 alloy (j ~ 1 J/cm2). After 50 pulses, the average grain size in the subsurface layer reaches ~2,2 μm for the VT1-0 alloy and ~1,6 μm for VT6. It should be noted that a rather uniform structure with equiaxed grains is formed as early as after treating with 1 high power ion beam pulse.

Effect of intense electron and ion irradiation on optical absorption of boron carbide thin films

ABSTRACTThe energetic characteristics of growth and radiation defects (RDs) in boron carbide films deposited by reactive magnetron sputtering on a steel substrate and irradiated with powerful electron and pulsed ion beams were investigated. The relationship between the characteristics of point RDs, the degree of distortion of the electronic structure and the characteristics of interband and exponential absorption was established. The absorption spectra of the films were due to electronic transitions between the defects energy states localized in the band gap and interband transitions. The stability of characteristics to electron irradiation was due to the high concentration of growth defects, distributed along the boundaries between the structural fragments. Short-pulse implantation of carbon ions stimulates partial annealing of intrinsic RDs and their redistribution and formation of thermally stable complexes from defects. Boron carbide films significantly exceed the radiation resistance of sodium calcium silicate glass, but are slightly inferior to the films of aluminum and silicon nitrides, obtained by magnetron deposition.

Radiation Stability of Metal Fe0.56Ni0.44 Nanowires Exposed to Powerful Pulsed Ion Beams

The resistance of Fe0.56Ni0.44 alloy nanowires (fabricated by template synthesis using polymer track membranes) 60 and 100 nm in diameter to radiation with powerful pulsed 85% C+ + 15% H+ ions (E = 20 keV, j = 100 A/cm2, τ = 90 ns) has been investigated. The conclusion that nanosized regions of explosive energy release, so-called thermal spikes, which are thermalized regions of dense cascades of atomic displacements heated to several thousand degrees (in which the thermal pressure can reach several tens of GPa), play an important role in the nanowire structure change is drawn. These are observed as melted nanosized regions on the nanowire surface. Calculations have shown that energy supplied by an ion beam during the action of a single pulse in the used mode (provided that thermal radiation and thermal conductivity serve as energy sinks) can be both sufficient and insufficient to completely melt nanowires depending on their orientation with respect to the ion beam. The bending and failure of nonmelted nanowires is explained by the generation and propagation of post-cascade shock waves.

Effect of powerful pulsed and continuous ion beams on the Al- Cu-Mg alloy structure

The paper considers the results of an electron microscopy study of the VD1 alloy of the Al-Cu-Mg system after cold working and subsequent irradiation with a powerful pulsed ion beam (70% C+ + 30% H+, E = 180 keV) in the pulsed-periodic mode (t = 80 ns, f = 0.1 Hz, j = 200 A/cm2, F = 1-1014 cm-2) and under the conditions of the generation of only one pulse (t = 180 ns, j = 100 A/cm2, F = 2-1015 cm-2). It is established that this irradiation noticeably affects the microstructure of the cold-worked 3 mm thick sheets of VD1 alloy. The initial cellular dislocation structure transforms into a subgrain one. The intensity of structural transformations in the alloy increases with ion current density of a pulse. A similar transformation of a dislocation structure over the entire thickness of the sample is observed under irradiation with continuous Ar+ ion beams (E = 20-40 keV) with not high fluences (1015-1016 cm-2).

Numerical investigation of the change of dislocation density and microhardness in surface layer of iron targets under the high power ion- and electron-beam treatment

The effect of the Low Energy High Current Pulsed Electron Beam (LEHCPEB) and High Power Pulsed Ion Beam (HPPIB) surface treatment on the dislocation density in iron target has been numerically investigated. At typical technological irradiation parameters the major factors for modification of dislocation density are the thermo-stresses in the heat affected zone. Irradiation regimes, within the process of which there is no melting, generate one maximum of dislocation density, at the same time the regimes resulting in melting produce two maximums of dislocation density: one of them is localized inside the layer which has crystallized from melt, and the other one at the melt–solid interface. The increase of enclosed energy density and the reduction of pulse duration make the excited stress wave even more significant for the dislocation modification. This wave causes hardening of the material in deeper layers which may eventually result in the influence on the whole volume of the target.

A gigawatt power pulsed ion beam generator for industrial applications

The results of a comprehensive study of a gigawatt level power pulsed ion beam used for material modification are presented. The ion beam is formed using a diode with self-magnetic insulation. The study was performed using the TEMP-4M accelerator in double pulse formation mode. The ion current density is 30–300A/cm2 (for different designs of diodes), and the beam is composed of protons (15%) and carbon ions (85%). It was shown that a diode with planar configuration generates an ion beam with a fairly homogeneous energy density over a cross section of 80cm2; the energy density is 0.3–0.4J/cm2 and the fluence is 2×1013cm−2 per pulse. A diode with focusing geometry forms an ion beam with an energy density of 2–2.5J/cm2 at the focus and a pulse energy of 80–100J.

Diagnostic Equipment for the TEMP-4M Generator of High-current Pulsed Ion Beams

The results of calibration and optimization of the diagnostic equipment for a gigawatt power pulsed ion beam accelerator are presented. The study was performed using the TEMP-4M accelerator set in the mode of double pulse formation. The first pulse is negative (300 – 600 ns, 100 – 150 kV), followed by the second positive pulse (80 ns, 250 – 300 kV). The ion current density is 30 – 300 A/cm(for different designs of diodes), the ion energy is 250 – 300 keV, and the beam is composed of protons and carbon ions. The calibration of the diagnostic equipment shows that it correctly reflects the accelerator operation in the short-circuit mode (U = 50 – 60 kV), when operating with a resistive load up to 10 Ω (200 – 300 kV) and when operating with a diode. A technique based on the time-of-flight (TOF) method for a quick determination of the beam’s composition (ion type and degree of ionization) was tested. The method allowed for the determination of the absolute values of the ion current density and the energy spectrum for each ion type with an accuracy of ±10%.

Changes in microstructure of cold-worked aluminum-lithium alloy 1441 initiated by powerful pulsed ion beams

The results of an electron microscopy study of alloy 1441 of the Al-Cu-Mg-Li-Zr-Mn system after cold rolling (ɛ = 72%) and subsequent irradiation with a powerful pulsed ion beam (70%C+ + 30%H+) in the pulsed-periodic mode (τ = 80 ns, f = 0.1 Hz) and under the conditions of the generation of only one pulse (τ = 180 ns) are considered. The ion energy was 180 keV. It is shown by transmission electron microscopy that low irradiation doses D = 1 × 1014–2 × 1015 cm−2 of cold-worked alloy 1441 cause a noticeable transformation of a cellular dislocation structure formed in it. It is shown that, as the ion current density increases in the pulse, the intensity of structural transformations in the alloy increases.

The effect of ion current density amplification in a diode with passive anode in magnetic self-isolation mode

The results of a study on gigawatt power pulsed ion beam parameters are presented here. The pulsed ion beam is formed by a diode with an explosive-emission potential electrode, in magnetic self-isolation mode [A. I. Pushkarev, J. I. Isakova, M. S. Saltimakov et al., Phys. Plasmas 17, 013104 (2010)]. The ion current density is 20–40 A/cm2, the energy of the ions is 200–250 keV, and the beam composition is of protons and carbon ions. Experiments have been performed on the TEMP-4M accelerator, set in double-pulse formation mode. To measure the beam parameters, we used a time-of-flight diagnosis. It is shown that the carbon ion current density, formed in a planar diode with graphite potential electrode, is five to seven times higher than the values calculated from the Child–Langmuir ratio. A model of ion current density amplification in a diode with magnetic self-isolation is proposed. The motion of electrons in the anode-cathode gap is simulated using the program CST PARTICLE STUDIO.

A model for the prediction of radiation defect profiles in the semiconductor target (HgCdTe) subjected to high power short pulsed ion beams

A mathematical model to describe processes occurring during the irradiation of semiconductor materials with high power pulsed ion beams is proposed. The model takes account of recombination between vacancies and interstitial atoms and the formation of defect complexes and these processes are analysed and discussed. The effect of an inhomogeneous non-stationary temperature field and mechanical quasi-static and dynamic stress fields on radiation defect profiles is also examined. Spatial profiles of the charge carrier concentration and the implanted ion distribution are calculated and a comparison made with experimental profiles obtained for the semiconductor compound Hg1−xCdxTe. The results show that the defect concentration profiles near the surface are reduced with a large rate of recombination between vacancy and interstitial atoms.

The high power pulsed ion beam mixing of a titanium layer with an aluminum substrate

This paper describes the MPOS application as an ion beam source for Ti film/Al substrate mixing. Single layer 500 nm films of titanium were deposited on aluminum 6061-T6 samples and then irradiated by an ion beam. The ion beam energy was between 200 and 250 keV, the pulse length was 100 ns and the ion current density was between 10 and 150 A/cm2. Characterization of the treated samples was done using the SEM, EDAX and Auger spectroscopy. Numerical calculations of the phase transitions in this system have been done, to estimate the ion current density needed for effective melting and mixing of the films and substrate. According to Auger analysis, significant mixing of the Ti film and Al substrate occurs up to depths of 1.3 μm. Corrosion tests have shown improved corrosion resistance for the mixed layer in comparison with the untreated film.

Pulsed ion beam formation of highly doped GaAs layers

The formation of heavily doped n-GaAs layers using continuous ion implantation and subsequent treatment by powerful pulsed ion beams has been investigated. Using Auger electron spectroscopy (AES), electrical measurements and computer simulations, correlation between donor distributions and electrical activation was established. It is shown that the n +-GaAs layers ( n=10 19–10 20 cm −3) are formed in the deep tail of the impurity atom distributions. Thermal stability of formed supersaturated layers was investigated.

Termomechanical processing of titanium alloys by high power pulsed ion beams

The effect of thermomechanical processing by high power pulsed ion beams (ions of C +and H +, energy, E=300 keV, ion current density in a pulse, j=20–220 A·cm −2, number of pulses, n=1–100, pulse duration, τ=50–100 ns) on the chemical composition and structure of titanium alloy parts surface layers (VT8M, VT9, VT18U and VT25U) were studied. It is shown that ion beam treatment and a post-process annealing allow the modification of the surface layers of the titanium alloy parts with thicknesses up to 100 μm. As a result of this complex treatment, service properties of the titanium alloy details can be improved cardinally. The prospects of high power pulsed ion beam treatment application for aircraft engine building are discussed.

Formation of heavily doped semiconductor layers by pulsed ion beam treatment

The formation of heavily doped Si and GaAs layers using implantation and powerful pulsed ion beams has been investigated. The influence of the depth distribution of energy released by the ions on the temperature profile and the electrically active impurity distribution in Si and GaAs is analyzed. It is shown that as a consequence of the simultaneous action of impurity diffusion processes normal to the surface and decomposition of GaAs at the surface, the heavily doped (8 × 10 19cm −3) layers are formed in the subsurface region (0.1–0.5 μm).

Metastable States and Structural Phase Changes in Metals and Alloys Exposed to High Power Pulsed Ion Beams

Metastable States and Structural Phase Changes in Metals and Alloys Exposed to High Power Pulsed Ion Beams

Pulsed Ion Beam Annealing Of Nickel Thin Films on Silicon

ABSTRACTHigh power pulsed ion beams have been applied to anneal nickel thin films on silicon. RBS and TEM have been performed to study ion beam induced effects. With Ba+ion beams at energy densities greater than 0.7 J/cm2and H+beams above about 1.3 J/cm2, cellular structures were found. At about 0.6 J/cm2for Ba+(about 1.0 J/cm2for H+), epitaxial NiSi2was formed. At lower energy densities, polycrystalline layers containing a mixture of silicide phases were observed. With ion beam annealing, melting starts at the Ni/Si interface and epitaxy was found at energy densities well below that required to melt Ni or crystalline Si.