Quantum Beam Science

Editorial

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2 pages, 162 KiB

Open AccessEditorial

Modifications of Metallic and Inorganic Materials by Using Ion/Electron Beams

by Akihiro Iwase

Quantum Beam Sci. 2022, 6(1), 1; https://doi.org/10.3390/qubs6010001 - 29 Dec 2021

Viewed by 1997

Abstract

Welcome to the Special Issue of Quantum Beam Science entitled “Modifications of Metallic and Inorganic Materials by Using Ion/Electron Beams” [...] Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

Research

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14 pages, 3872 KiB

Open AccessArticle

Nanopore Formation in CeO₂ Single Crystal by Ion Irradiation: A Molecular Dynamics Study

by Yasushi Sasajima, Ryuichi Kaminaga, Norito Ishikawa and Akihiro Iwase

Quantum Beam Sci. 2021, 5(4), 32; https://doi.org/10.3390/qubs5040032 - 18 Nov 2021

Cited by 2 | Viewed by 2740

Abstract

The nanopore formation process that occurs by supplying a thermal spike to single crystal CeO₂ has been simulated using a molecular dynamics method. As the initial condition, high thermal energy was supplied to the atoms in a nano-cylinder placed at the center [...] Read more.

The nanopore formation process that occurs by supplying a thermal spike to single crystal CeO₂ has been simulated using a molecular dynamics method. As the initial condition, high thermal energy was supplied to the atoms in a nano-cylinder placed at the center of a fluorite structure. A nanopore was generated abruptly at around 0.3 ps after the irradiation, grew to its maximum size at 0.5 ps, shrank during the time to 1.0 ps, and finally equilibrated. The nanopore size increased with increasing effective stopping power gSe (i.e., the thermal energy deposited per unit length in the specimen), but it became saturated when gSe was 0.8 keV/nm or more. This finding will provide useful information for precise control of the size of nanopores. Our simulation confirmed nanopore formation found in the actual experiment, irradiation of CeO₂ with swift heavy ions, but could not reproduce crystalline hillock formation just above the nanopores. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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22 pages, 1757 KiB

Open AccessArticle

Modification of SiO₂, ZnO, Fe₂O₃ and TiN Films by Electronic Excitation under High Energy Ion Impact

by Noriaki Matsunami, Masao Sataka, Satoru Okayasu and Bun Tsuchiya

Quantum Beam Sci. 2021, 5(4), 30; https://doi.org/10.3390/qubs5040030 - 27 Oct 2021

Cited by 4 | Viewed by 3137

Abstract

It has been known that the modification of non-metallic solid materials (oxides, nitrides, etc.), e.g., the formation of tracks, sputtering representing atomic displacement near the surface and lattice disordering are induced by electronic excitation under high-energy ion impact. We have investigated lattice disordering [...] Read more.

It has been known that the modification of non-metallic solid materials (oxides, nitrides, etc.), e.g., the formation of tracks, sputtering representing atomic displacement near the surface and lattice disordering are induced by electronic excitation under high-energy ion impact. We have investigated lattice disordering by the X-ray diffraction (XRD) of SiO₂, ZnO, Fe₂O₃ and TiN films and have also measured the sputtering yields of TiN for a comparison of lattice disordering with sputtering. We find that both the degradation of the XRD intensity per unit ion fluence and the sputtering yields follow the power-law of the electronic stopping power and that these exponents are larger than unity. The exponents for the XRD degradation and sputtering are found to be comparable. These results imply that similar mechanisms are responsible for the lattice disordering and electronic sputtering. A mechanism of electron–lattice coupling, i.e., the energy transfer from the electronic system into the lattice, is discussed based on a crude estimation of atomic displacement due to Coulomb repulsion during the short neutralization time (~fs) in the ionized region. The bandgap scheme or exciton model is examined. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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9 pages, 2568 KiB

Open AccessArticle

Effect of Irradiation on Corrosion Behavior of 316L Steel in Lead-Bismuth Eutectic with Different Oxygen Concentrations

by Nariaki Okubo, Yuki Fujimura and Masakatsu Tomobe

Quantum Beam Sci. 2021, 5(3), 27; https://doi.org/10.3390/qubs5030027 - 31 Aug 2021

Cited by 8 | Viewed by 3727

Abstract

In an accelerator-driven system (ADS), the beam window material of the spallation neutron target is heavily irradiated under severe conditions, in which the radiation damage and corrosion co-occur because of high-energy neutron and/or proton irradiation in the lead–bismuth flow. The materials used in [...] Read more.

In an accelerator-driven system (ADS), the beam window material of the spallation neutron target is heavily irradiated under severe conditions, in which the radiation damage and corrosion co-occur because of high-energy neutron and/or proton irradiation in the lead–bismuth flow. The materials used in ADSs must be compatible with the liquid metal (lead–bismuth eutectic (LBE)) to prevent issues such as liquid metal embrittlement (LME) and liquid metal corrosion (LMC). This study considers the LMC behavior after ion irradiation of 316L austenitic steel for self-ion irradiations followed by the corrosion tests in LBE with critical oxygen concentration. The 316L samples were irradiated by 10.5 MeV-Fe³⁺ ions at a temperature of 450 °C, up to 50 displacements per atom (dpa). After the corrosion test performed at 450 °C in LBE with low oxygen concentration, a surface of the nonirradiated area was not oxidized but appeared with locally corrosive morphology, Ni depletion, whereas an iron/chromium oxide layer fully covered the irradiated area. In the case of the corrosion surface with high oxygen concentration in LBE, the surface of the nonirradiated area was covered by an iron oxide layer only, whereas the irradiated area was covered by the duplex layers comprising iron and iron/chromium oxides. It is suggested that irradiation can enhance the oxide layer formation because of the enhancement of Fe and/or oxygen diffusion induced by the radiation defects in 316L steel. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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12 pages, 6297 KiB

Open AccessFeature PaperArticle

Fabrication of Size- and Shape-Controlled Platinum Cones by Ion-Track Etching and Electrodeposition Techniques for Electrocatalytic Applications

by Yuma Sato, Hiroshi Koshikawa, Shunya Yamamoto, Masaki Sugimoto, Shin-ichi Sawada and Tetsuya Yamaki

Quantum Beam Sci. 2021, 5(3), 21; https://doi.org/10.3390/qubs5030021 - 1 Jul 2021

Cited by 3 | Viewed by 3443

Abstract

The micro/nanocone structures of noble metals play a critical role as heterogeneous electrocatalysts that provide excellent activity. We successfully fabricated platinum cones by electrodeposition using non-penetrated porous membranes as templates. This method involved the preparation of template membranes by the swift-heavy-ion irradiation of [...] Read more.

The micro/nanocone structures of noble metals play a critical role as heterogeneous electrocatalysts that provide excellent activity. We successfully fabricated platinum cones by electrodeposition using non-penetrated porous membranes as templates. This method involved the preparation of template membranes by the swift-heavy-ion irradiation of commercially available polycarbonate films and subsequent chemical etching in an aqueous NaOH solution. The surface diameter, depth, aspect ratio and cone angle of the resulting conical pores were controlled in the ranges of approximately 70–1500 nm, 0.7–11 μm, 4–12 and 5–13°, respectively, by varying the etching conditions, which finally produced size- and shape-controlled platinum cones with nanotips. In order to demonstrate the electrocatalytic activity, electrochemical measurements were performed for the ethanol oxidation reaction. The oxidation activity was found to be up to 3.2 times higher for the platinum cone arrays than for the platinum plate. Ion-track etching combined with electrodeposition has the potential to be an effective method for the fabrication of micro/nanocones with high electrocatalytic performance. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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9 pages, 2223 KiB

Open AccessArticle

Phase Transformation by 100 keV Electron Irradiation in Partially Stabilized Zirconia

by Yasuki Okuno and Nariaki Okubo

Quantum Beam Sci. 2021, 5(3), 20; https://doi.org/10.3390/qubs5030020 - 25 Jun 2021

Cited by 4 | Viewed by 3055

Abstract

Partially stabilized zirconia (PSZ) is considered for use as an oxygen-sensor material in liquid lead-bismuth eutectic (LBE) alloys in the radiation environment of an acceleration-driven system (ADS). To predict its lifetime for operating in an ADS, the effects of radiation on the PSZ [...] Read more.

Partially stabilized zirconia (PSZ) is considered for use as an oxygen-sensor material in liquid lead-bismuth eutectic (LBE) alloys in the radiation environment of an acceleration-driven system (ADS). To predict its lifetime for operating in an ADS, the effects of radiation on the PSZ were clarified in this study. A tetragonal PSZ was irradiated with 100 keV electrons and analyzed by X-ray diffraction (XRD). The results indicate that the phase transition in the PSZ, from the tetragonal to the monoclinic phase, was caused after the irradiation. The deposition energy of the lattice and the deposition energy for the displacement damage of a 100 keV electron in the PSZ are estimated using the particle and heavy ion transport code system and the non-ionizing energy loss, respectively. The results suggest that conventional radiation effects, such as stopping power, are not the main mechanism behind the phase transition. The phase transition is known to be caused by the low-temperature degradation of the PSZ and is attributed to the shift of oxygen ions to oxygen sites. When the electron beam is incident to the material, the kinetic energy deposition and excitation-related processes are caused, and it is suggested to be a factor of the phase transition. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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8 pages, 1186 KiB

Open AccessArticle

Effect of 1.5 MeV Proton Irradiation on Superconductivity in FeSe_0.5Te_0.5 Thin Films

by Toshinori Ozaki, Takuya Kashihara, Itsuhiro Kakeya and Ryoya Ishigami

Quantum Beam Sci. 2021, 5(2), 18; https://doi.org/10.3390/qubs5020018 - 4 Jun 2021

Cited by 4 | Viewed by 3444

Abstract

Raising the critical current density J_c in magnetic fields is crucial to applications such as rotation machines, generators for wind turbines and magnet use in medical imaging machines. The increase in J_c has been achieved by introducing structural defects including precipitates [...] Read more.

Raising the critical current density J_c in magnetic fields is crucial to applications such as rotation machines, generators for wind turbines and magnet use in medical imaging machines. The increase in J_c has been achieved by introducing structural defects including precipitates and vacancies. Recently, a low-energy ion irradiation has been revisited as a practically feasible approach to create nanoscale defects, resulting in an increase in J_c in magnetic fields. In this paper, we report the effect of proton irradiation with 1.5 MeV on superconducting properties of iron–chalcogenide FeSe_0.5Te_0.5 films through the transport and magnetization measurements. The 1.5 MeV proton irradiation with 1 × 10¹⁶ p/cm² yields the highest J_c increase, approximately 30% at 5–10 K and below 1 T without any reduction in T_c. These results indicate that 1.5 MeV proton irradiations could be a practical tool to enhance the performance of iron-based superconducting tapes under magnetic fields. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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12 pages, 6571 KiB

Open AccessFeature PaperArticle

Effects of Beam Conditions in Ground Irradiation Tests on Degradation of Photovoltaic Characteristics of Space Solar Cells

by Mitsuru Imaizumi, Takeshi Ohshima, Yosuke Yuri, Kohtaku Suzuki and Yoshifumi Ito

Quantum Beam Sci. 2021, 5(2), 15; https://doi.org/10.3390/qubs5020015 - 20 May 2021

Cited by 4 | Viewed by 4318

Abstract

We investigated the effects of irradiation beam conditions on the performance degradation of silicon and triple-junction solar cells for use in space. The fluence rates of electron and proton beams were varied. Degradation did not depend on the fluence rate of protons for [...] Read more.

We investigated the effects of irradiation beam conditions on the performance degradation of silicon and triple-junction solar cells for use in space. The fluence rates of electron and proton beams were varied. Degradation did not depend on the fluence rate of protons for both cells. A higher fluence rate of electrons caused greater degradation of the Si cell, but the dependence was due to the temperature increase during irradiation. Two beam-area expansion methods, defocusing and scanning, were examined for proton irradiation of various energies (50 keV–10 MeV). In comparing the output degradation from irradiation with defocused and scanned proton beams, no significant difference in degradation was found for any proton energy. We plan to reflect these findings into ISO standard of irradiation test method of space solar cells. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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11 pages, 3987 KiB

Open AccessFeature PaperArticle

Simulation of Two-Dimensional Images for Ion-Irradiation Induced Change in Lattice Structures and Magnetic States in Oxides by Using Monte Carlo Method

by Akihiro Iwase and Shigeru Nishio

Quantum Beam Sci. 2021, 5(2), 13; https://doi.org/10.3390/qubs5020013 - 13 May 2021

Cited by 1 | Viewed by 2500

Abstract

A Monte Carlo method was used to simulate the two-dimensional images of ion-irradiation-induced change in lattice structures and magnetic states in oxides. Under the assumption that the lattice structures and the magnetic states are modified only inside the narrow one-dimensional region along the [...] Read more.

A Monte Carlo method was used to simulate the two-dimensional images of ion-irradiation-induced change in lattice structures and magnetic states in oxides. Under the assumption that the lattice structures and the magnetic states are modified only inside the narrow one-dimensional region along the ion beam path (the ion track), and that such modifications are affected by ion track overlapping, the exposure of oxide targets to spatially random ion impacts was simulated by the Monte Carlo method. Through the Monte Carlo method, the evolutions of the two-dimensional images for the amorphization of TiO₂, the lattice structure transformation of ZrO₂, and the transition of magnetic states of CeO₂ were simulated as a function of ion fluence. The total fractions of the modified areas were calculated from the two-dimensional images. They agree well with the experimental results and those estimated by using the Poisson distribution functions. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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9 pages, 7104 KiB

Open AccessArticle

Desorption of Implanted Deuterium in Heavy Ion-Irradiated Zry-2

by Hideo Watanabe, Yoshiki Saita, Katsuhito Takahashi and Kazufumi Yasunaga

Quantum Beam Sci. 2021, 5(2), 9; https://doi.org/10.3390/qubs5020009 - 26 Apr 2021

Cited by 1 | Viewed by 2623

Abstract

To understand the degradation behavior of light water reactor (LWR) fuel-cladding tubes under neutron irradiation, a detailed mechanism of hydrogen pickup related to the point defect formation (i.e., a-component and c-component dislocation loops) and to the dissolution of precipitates must be elucidated. In [...] Read more.

To understand the degradation behavior of light water reactor (LWR) fuel-cladding tubes under neutron irradiation, a detailed mechanism of hydrogen pickup related to the point defect formation (i.e., a-component and c-component dislocation loops) and to the dissolution of precipitates must be elucidated. In this study, 3.2 MeV Ni³⁺ ion irradiation was conducted on Zircaloy-2 samples at room temperature. Thermal desorption spectroscopy is used to evaluate the deuterium desorption with and without Ni³⁺ ion irradiation. A conventional transmission electron microscope and a spherical aberration-corrected high-resolution analytical electron microscope are used to observe the microstructure. The experimental results indicate that radiation-induced dislocation loops and hydrides form in Zircaloy-2 and act as major trapping sites at lower (400–600 °C) and higher (700–900 °C)-temperature regions, respectively. These results show that the detailed microstructural changes related to the hydrogen pickup at the defect sinks formed by irradiation are necessary for the degradation of LWR fuel-cladding tubes during operation. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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8 pages, 651 KiB

Open AccessArticle

Chromatic Change in Copper Oxide Layers Irradiated with Low Energy Ions

by Takuya Kobayashi, Fumitaka Nishiyama and Katsumi Takahiro

Quantum Beam Sci. 2021, 5(1), 7; https://doi.org/10.3390/qubs5010007 - 10 Mar 2021

Cited by 2 | Viewed by 2681

Abstract

The color of a thin copper oxide layer formed on a copper plate was transformed from reddish-brown into dark blue-purple by irradiation with 5 keV Ar⁺ ions to a fluence as low as 1 × 10¹⁵ Ar⁺ cm⁻². [...] Read more.

The color of a thin copper oxide layer formed on a copper plate was transformed from reddish-brown into dark blue-purple by irradiation with 5 keV Ar⁺ ions to a fluence as low as 1 × 10¹⁵ Ar⁺ cm⁻². In the unirradiated copper oxide layer, the copper valence state of Cu²⁺ and Cu⁺ and/or Cu⁰ was included as indicated by the presence of a shake-up satellite line in a photoemission spectrum. While for the irradiated one, the satellite line decreased in intensity, indicating that irradiation resulted in the reduction from Cu²⁺ to Cu⁺ and/or Cu⁰. Furthermore, nuclear reaction analysis using a ¹⁶O(d, p)¹⁷O reaction with 0.85 MeV deuterons revealed a significant loss of oxygen (5 × 10¹⁵ O atoms cm⁻²) in the irradiated layer. Thus, the chromatic change observed in the present work originated in the irradiation-induced reduction of a copper oxide. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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7 pages, 3274 KiB

Open AccessArticle

Development of Pulsed TEM Equipped with Nitride Semiconductor Photocathode for High-Speed Observation and Material Nanofabrication

by Hidehiro Yasuda, Tomohiro Nishitani, Shuhei Ichikawa, Shuhei Hatanaka, Yoshio Honda and Hiroshi Amano

Quantum Beam Sci. 2021, 5(1), 5; https://doi.org/10.3390/qubs5010005 - 1 Feb 2021

Cited by 5 | Viewed by 3212

Abstract

The development of pulsed electron sources is applied to electron microscopes or electron beam lithography and is effective in expanding the functions of such devices. The laser photocathode can generate short pulsed electrons with high emittance, and the emittance can be increased by [...] Read more.

The development of pulsed electron sources is applied to electron microscopes or electron beam lithography and is effective in expanding the functions of such devices. The laser photocathode can generate short pulsed electrons with high emittance, and the emittance can be increased by changing the cathode substrate from a metal to compound semiconductor. Among the substrates, nitride-based semiconductors with a negative electron affinity (NEA) have good advantages in terms of vacuum environment and cathode lifetime. In the present study, we report the development of a photocathode electron gun that utilizes photoelectron emission from a NEA-InGaN substrate by pulsed laser excitation, and the purpose is to apply it to material nanofabrication and high-speed observation using a pulsed transmission electron microscope (TEM) equipped with it. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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9 pages, 1793 KiB

Open AccessArticle

Irradiation Hardening Behavior of He-Irradiated V–Cr–Ti Alloys with Low Ti Addition

by Ken-ichi Fukumoto, Yoshiki Kitamura, Shuichiro Miura, Kouji Fujita, Ryoya Ishigami and Takuya Nagasaka

Quantum Beam Sci. 2021, 5(1), 1; https://doi.org/10.3390/qubs5010001 - 31 Dec 2020

Cited by 7 | Viewed by 2910

Abstract

A set of V–(4–8)Cr–(0–4)Ti alloys was fabricated to survey an optimum composition to reduce the radioactivity of V–Cr–Ti alloys. These alloys were subjected to nano-indenter tests before and after 2-MeV He-ion irradiation at 500 °C and 700 °C with 0.5 dpa at peak [...] Read more.

A set of V–(4–8)Cr–(0–4)Ti alloys was fabricated to survey an optimum composition to reduce the radioactivity of V–Cr–Ti alloys. These alloys were subjected to nano-indenter tests before and after 2-MeV He-ion irradiation at 500 °C and 700 °C with 0.5 dpa at peak damage to investigate the effect of Cr and Ti addition and gas impurities for irradiation hardening behavior in V–Cr–Ti alloys. Cr and Ti addition to V–Cr–Ti alloys for solid–solution hardening remains small in the unirradiated V–(4–8)Cr–(0–4)Ti alloys. Irradiation hardening occurred for all V–Cr–Ti alloys. The V–4Cr–1Ti alloy shows the highest irradiation hardening among all V–Cr–Ti alloys and the gas impurity was enhanced to increase the irradiation hardening. These results may arise from the formation of Ti(CON) precipitate that was produced by He-ion irradiation. Irradiation hardening of V–Cr–1Ti did not depend significantly on Cr addition. Consequently, for irradiation hardening and void-swelling suppression, the optimum composition of V–Cr–Ti alloys for structural materials of fusion reactor engineering is proposed to be a highly purified V–(6–8)Cr–2Ti alloy. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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14 pages, 5505 KiB

Open AccessArticle

Comprehensive Understanding of Hillocks and Ion Tracks in Ceramics Irradiated with Swift Heavy Ions

by Norito Ishikawa, Tomitsugu Taguchi and Hiroaki Ogawa

Quantum Beam Sci. 2020, 4(4), 43; https://doi.org/10.3390/qubs4040043 - 9 Dec 2020

Cited by 11 | Viewed by 3523

Abstract

Amorphizable ceramics (LiNbO₃, ZrSiO₄, and Gd₃Ga₅O₁₂) were irradiated with 200 MeV Au ions at an oblique incidence angle, and the as-irradiated samples were observed by transmission electron microscopy (TEM). Ion tracks in amorphizable [...] Read more.

Amorphizable ceramics (LiNbO₃, ZrSiO₄, and Gd₃Ga₅O₁₂) were irradiated with 200 MeV Au ions at an oblique incidence angle, and the as-irradiated samples were observed by transmission electron microscopy (TEM). Ion tracks in amorphizable ceramics are confirmed to be homogenous along the ion paths. Magnified TEM images show the formation of bell-shaped hillocks. The ion track diameter and hillock diameter are similar for all the amorphizable ceramics, while there is a tendency for the hillocks to be slightly bigger than the ion tracks. For SrTiO₃ (STO) and 0.5 wt% niobium-doped STO (Nb-STO), whose hillock formation has not been fully explored, 200 MeV Au ion irradiation and TEM observation were also performed. The ion track diameters in these materials are found to be markedly smaller than the hillock diameters. The ion tracks in these materials exhibit inhomogeneity, which is similar to that reported for non-amorphizable ceramics. On the other hand, the hillocks appear to be amorphous, and the amorphous feature is in contrast to the crystalline feature of hillocks observed in non-amorphizable ceramics. No marked difference is recognized between the nanostructures in STO and those in Nb-STO. The material dependence of the nanostructure formation is explained in terms of the intricate recrystallization process. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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11 pages, 2635 KiB

Open AccessArticle

Irradiation Effects of Swift Heavy Ions Detected by Refractive Index Depth Profiling

by Hiroshi Amekura, Rang Li, Nariaki Okubo, Norito Ishikawa and Feng Chen

Quantum Beam Sci. 2020, 4(4), 39; https://doi.org/10.3390/qubs4040039 - 16 Nov 2020

Cited by 2 | Viewed by 2792

Abstract

Evolution of depth profiles of the refractive index in Y₃Al₅O₁₂ (YAG) crystals were studied under 200 MeV ¹³⁶Xe¹⁴⁺ ion irradiation, since the index can be related with the stress change and/or the defect formation by the [...] Read more.

Evolution of depth profiles of the refractive index in Y₃Al₅O₁₂ (YAG) crystals were studied under 200 MeV ¹³⁶Xe¹⁴⁺ ion irradiation, since the index can be related with the stress change and/or the defect formation by the irradiation. Using the prism-coupling and the end-surface coupling methods, various waveguide (WG) modes were detected. Then, the index depth profiles were determined by reproducing the observed WG modes. The index changes were observed at three different depth regions; (i) a sharp dip at 13 μm in depth, which is attributed to the nuclear stopping S_n peak, (ii) a plateau near the surface between 0 and 3 μm in depth, which can be ascribed to the electronic stopping S_e, since S_e has a very broad peak at the surface, and (iii) a broad peak at 6 μm in depth. Since the last peak is ascribed to neither of S_e nor S_n peak, it could be attributed to the synergy effect of S_e and S_n. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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Review

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20 pages, 18557 KiB

Open AccessReview

Control and Modification of Nanostructured Materials by Electron Beam Irradiation

by Shun-Ichiro Tanaka

Quantum Beam Sci. 2021, 5(3), 23; https://doi.org/10.3390/qubs5030023 - 21 Jul 2021

Cited by 4 | Viewed by 4449

Abstract

I have proposed a bottom-up technology utilising irradiation with active beams, such as electrons and ions, to achieve nanostructures with a size of 3–40 nm. This can be used as a nanotechnology that provides the desired structures, materials, and phases at desired positions. [...] Read more.

I have proposed a bottom-up technology utilising irradiation with active beams, such as electrons and ions, to achieve nanostructures with a size of 3–40 nm. This can be used as a nanotechnology that provides the desired structures, materials, and phases at desired positions. Electron beam irradiation of metastable θ-Al₂O₃, more than 10¹⁹ e/cm²s in a transmission electron microscope (TEM), enables the production of oxide-free Al nanoparticles, which can be manipulated to undergo migration, bonding, rotation, revolution, and embedding. The manipulations are facilitated by momentum transfer from electrons to nanoparticles, which takes advantage of the spiral trajectory of the electron beam in the magnetic field of the TEM pole piece. Furthermore, onion-like fullerenes and intercalated structures on amorphous carbon films are induced through catalytic reactions. δ-, θ-Al₂O₃ ball/wire hybrid nanostructures were obtained in a short time using an electron irradiation flashing mode that switches between 10¹⁹ and 10²² e/cm²s. Various α-Al₂O₃ nanostructures, such as encapsulated nanoballs or nanorods, are also produced. In addition, the preparation or control of Pt, W, and Cu nanoparticles can be achieved by electron beam irradiation with a higher intensity. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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23 pages, 4221 KiB

Open AccessReview

Review of Swift Heavy Ion Irradiation Effects in CeO₂

by William F. Cureton, Cameron L. Tracy and Maik Lang

Quantum Beam Sci. 2021, 5(2), 19; https://doi.org/10.3390/qubs5020019 - 16 Jun 2021

Cited by 25 | Viewed by 6227

Abstract

Cerium dioxide (CeO₂) exhibits complex behavior when irradiated with swift heavy ions. Modifications to this material originate from the production of atomic-scale defects, which accumulate and induce changes to the microstructure, chemistry, and material properties. As such, characterizing its radiation response [...] Read more.

Cerium dioxide (CeO₂) exhibits complex behavior when irradiated with swift heavy ions. Modifications to this material originate from the production of atomic-scale defects, which accumulate and induce changes to the microstructure, chemistry, and material properties. As such, characterizing its radiation response requires a wide range of complementary characterization techniques to elucidate the defect formation and stability over multiple length scales, such as X-ray and neutron scattering, optical spectroscopy, and electron microscopy. In this article, recent experimental efforts are reviewed in order to holistically assess the current understanding and knowledge gaps regarding the underlying physical mechanisms that dictate the response of CeO₂ and related materials to irradiation with swift heavy ions. The recent application of novel experimental techniques has provided additional insight into the structural and chemical behavior of irradiation-induced defects, from the local, atomic-scale arrangement to the long-range structure. However, future work must carefully account for the influence of experimental conditions, with respect to both sample properties (e.g., grain size and impurity content) and ion-beam parameters (e.g., ion mass and energy), to facilitate a more direct comparison of experimental results. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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21 pages, 8129 KiB

Open AccessReview

Modification of Critical Current Density Anisotropy in High-T_c Superconductors by Using Heavy-Ion Irradiations

by Tetsuro Sueyoshi

Quantum Beam Sci. 2021, 5(2), 16; https://doi.org/10.3390/qubs5020016 - 21 May 2021

Cited by 16 | Viewed by 4292

Abstract

The critical current density J_c, which is a maximum value of zero-resistivity current density, is required to exhibit not only larger value but also lower anisotropy in a magnetic field B for applications of high-T_c superconductors. Heavy-ion irradiation introduces [...] Read more.

The critical current density J_c, which is a maximum value of zero-resistivity current density, is required to exhibit not only larger value but also lower anisotropy in a magnetic field B for applications of high-T_c superconductors. Heavy-ion irradiation introduces nanometer-scale irradiation tracks, i.e., columnar defects (CDs) into high-T_c superconducting materials, which can modify both the absolute value and the anisotropy of J_c in a controlled manner: the unique structures of CDs, which significantly affect the J_c properties, are engineered by adjusting the irradiation conditions such as the irradiation energy and the incident direction. This paper reviews the modifications of the J_c anisotropy in high-T_c superconductors using CDs installed by heavy-ion irradiations. The direction-dispersion of CDs, which is tuned by the combination of the plural irradiation directions, can provide a variety of the magnetic field angular variations of J_c in high-T_c superconductors: CDs crossing at ±θ_i relative to the c-axis of YBa₂Cu₃O_y films induce a broad peak of J_c centered at B || c for θ_i < ±45°, whereas the crossing angle of θ_i ≥ ±45° cause not a J_c peak centered at B || c but two peaks of J_c at the irradiation angles. The anisotropy of J_c can also modified by tuning the continuity of CDs: short segmented CDs formed by heavy-ion irradiation with relatively low energy are more effective to improve J_c in a wide magnetic field angular region. The modifications of the J_c anisotropy are discussed on the basis of both structures of CDs and flux line structures depending on the magnetic field directions. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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17 pages, 7144 KiB

Open AccessReview

Ion Accelerator Facility of the Wakasa Wan Energy Research Center for the Study of Irradiation Effects on Space Electronics

by Satoshi Hatori, Ryoya Ishigami, Kyo Kume and Kohtaku Suzuki

Quantum Beam Sci. 2021, 5(2), 14; https://doi.org/10.3390/qubs5020014 - 13 May 2021

Cited by 5 | Viewed by 4060

Abstract

The core facility of the Wakasa Wan Energy Research Center (WERC) consists of three ion accelerators: a synchrotron, a tandem accelerator and an ion-implanter. Research on the irradiation effects using these accelerators has been performed on space electronics such as solar cells, radiation [...] Read more.

The core facility of the Wakasa Wan Energy Research Center (WERC) consists of three ion accelerators: a synchrotron, a tandem accelerator and an ion-implanter. Research on the irradiation effects using these accelerators has been performed on space electronics such as solar cells, radiation detectors, image sensors and LSI circuits. In this report, the accelerator facility and ion-irradiation apparatuses at WERC are introduced, focusing on the research on irradiation effects on space electronics. Then, some recent results are summarized. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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20 pages, 15952 KiB

Open AccessReview

Self-Organized Nanostructures Generated on Metal Surfaces under Electron Irradiation

by Keisuke Niwase

Quantum Beam Sci. 2021, 5(1), 4; https://doi.org/10.3390/qubs5010004 - 19 Jan 2021

Cited by 3 | Viewed by 3205

Abstract

Irradiation of high-energy electrons can produce surface vacancies on the exit surface of thin foils by the sputtering of atoms. Although the sputtering randomly occurs in the area irradiated with an intense electron beam of several hundred nanometers in diameter, characteristic topographic features [...] Read more.

Irradiation of high-energy electrons can produce surface vacancies on the exit surface of thin foils by the sputtering of atoms. Although the sputtering randomly occurs in the area irradiated with an intense electron beam of several hundred nanometers in diameter, characteristic topographic features can appear under irradiation. This paper reviews a novel phenomenon on a self-organization of nanogrooves and nanoholes generated on the exit surface of thin metal foils irradiated with high doses of 360–1250 keV electrons. The phenomenon was discovered firstly for gold irradiated at temperatures about 100 K, which shows the formation of grooves and holes with widths between 1 and 2 nm. Irradiation along [001] produces grooves extending along [100] and [010], irradiation along [011] gives grooves along [100], whereas no clear grooves have been observed for [111] irradiations. By contrast, nanoholes, which may reach depths exceeding 20 nm, develop mainly along the beam direction. The formation of the nanostructures depends on the irradiation temperatures, exhibiting an existence of a critical temperature at about 240 K, above which the width significantly increases, and the density decreases. Nanostructures formed for silver, copper, nickel, and iron were also investigated. The self-organized process was discussed in terms of irradiation-induced effects. Full article

(This article belongs to the Special Issue The Modifications of Metallic and Inorganic Materials by Using Energetic Ion/Electron Beams)

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