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Journal Articles

FE-SEM observations of multiple nanohillocks on SrTiO$$_{3}$$ irradiated with swift heavy ions

Kitamura, Akane; Ishikawa, Norito; Kondo, Keietsu; Fujimura, Yuki; Yamamoto, Shunya*; Yamaki, Tetsuya*

Transactions of the Materials Research Society of Japan, 44(3), p.85 - 88, 2019/06

Swift heavy ions can create nanosized hillocks on the surfaces of various ceramics. When these materials are irradiated with swift heavy ions at normal incidence, each ion impact results in the formation of a single hillock on the surfaces. In contrast, irradiation at grazing incidence forms chains of multiple hillocks on the surface, for example, for strontium titanate (SrTiO$$_{3}$$). So far, chains of multiple hillocks have been investigated using atomic force microscopy (AFM). It should be noted that AFM measurements involve systematic errors of several nanometers due to the finite size of the probe tip. Consequently, it is possible that the image of one hillock may merge with that of a neighboring hillock even if the two hillocks are well separated. In contrast to AFM, field-emission scanning electron microscopy (FE-SEM) is a useful technique for obtaining higher-resolution images. In this study, we observed multiple nanohillocks on the surfaces of SrTiO$$_{3}$$ using FE-SEM. Crystals of SrTiO$$_{3}$$(100) and 0.05 wt% Nb-doped SrTiO$$_{3}$$(100) were irradiated with 350 MeV Xe ions, respectively, at grazing incidence, where the angle between the sample surface and the beam was less than 2$$^{circ}$$. On the SrTiO$$_{3}$$ surface, a chain of periodic nanohillocks is created along the ion path. In contrast, black lines accompanied by hillocks are observed on the Nb-doped SrTiO$$_{3}$$ surface.

Journal Articles

Progress of the J-PARC cesiated rf-driven negative hydrogen ion source

Shinto, Katsuhiro; Okoshi, Kiyonori; Shibata, Takanori*; Nammo, Kesao*; Ikegami, Kiyoshi*; Takagi, Akira*; Namekawa, Yuya*; Ueno, Akira; Oguri, Hidetomo

AIP Conference Proceedings 2052, p.050002_1 - 050002_7, 2018/12

In the 2017/2018 campaign, the J-PARC cesiated rf-driven negative hydrogen (H$$^-$$) ion source producing H$$^-$$ beam with the beam current of 47 mA accomplished three long-term operations more than 2,000 hours without any serious issues. On the final day of this campaign, the ion source produced an H$$^-$$ beam current of 72 mA so that the linac commissioning group could demonstrate the beam current of 60 mA at the linac exit. We are also conducting an endurance test of a J-PARC-made antenna at a test bench. The antenna achieved the operation time approximately 1,400 hours.

Journal Articles

Fluoropolymer-based nanostructured membranes created by swift-heavy-ion irradiation and their energy and environmental applications

Yamaki, Tetsuya*; Nuryanthi, N.*; Kitamura, Akane; Koshikawa, Hiroshi*; Sawada, Shinichi*; Voss, K.-O.*; Severin, D.*; Tautmann, C.*

Nuclear Instruments and Methods in Physics Research B, 435, p.162 - 168, 2018/11

 Percentile:100(Instruments & Instrumentation)

We used individual single-ion tracks in fluoropolymers with diameters of tens to hundreds of nanometers; chemical etching and ion-track grafting enabled us to develop ion-track and proton-conductive membranes, respectively. In the ion-track membranes of PVDF, strongly-LET-dependent etching was found, so the pore shape as well as the size was exclusively controlled by the track structures. We performed the ion-track grafting of styrene into ETFE to develop nanostructure-controlled proton exchange membranes (PEMs) for applications in PEM fuel cells. Our ion beam technology to develop fluoropolymer-based nanostructures has the potential to apply in the field of filtration processes and fuel cell devices. This would make it possible to provide new microfiltration technology for water treatment, sterilization, petroleum refining and dairy processing.

Journal Articles

Observation of beam current fluctuation extracted from an RF-driven H$$^-$$ ion source

Shinto, Katsuhiro; Shibata, Takanori*; Miura, Akihiko; Miyao, Tomoaki*; Wada, Motoi*

AIP Conference Proceedings 2011, p.080016_1 - 080016_3, 2018/09

Journal Articles

Research on nanostructure-controlled functional membranes using high-energy ion beams; Fluoropolymer-based porous and ion-exchange membranes

Yamaki, Tetsuya*; Kitamura, Akane; Sawada, Shinichi*; Koshikawa, Hiroshi*

Nippon Kaisui Gakkai-Shi, 72(2), p.62 - 74, 2018/04

This review paper is devoted to two topics, i.e., fluoropolymer-based porous and ion-exchange membranes, both of which include the creation of nanostructure-controlled functional membranes with high-energy ion beams. Latent tracks of the MeV-GeV heavy ions in a polymer foil can sometimes be chemically etched out to form a membrane with micro- and nano-sized through-pores, the so-called ion-track membrane. Our focus is on ion-track membranes of poly (vinylidene fluoride) (PVDF) and cation- and anion-exchange membranes (CEMs and AEMs, respectively).

Journal Articles

Preparation of nano-structure controlled ion-exchange membranes by ion beams and their application to seawater concentration

Yamaki, Tetsuya*; Goto, Mitsuaki*; Sawada, Shinichi*; Koshikawa, Hiroshi*; Kitamura, Akane; Higa, Mitsuru*

QST-M-8; QST Takasaki Annual Report 2016, P. 35, 2018/03

We prepared ion exchange membranes by a heavy-ion-track grafting method, and then used them for seawater concentration process. Both the water uptake and resistance were lower for our ion-track grafted membranes than for the conventional $$gamma$$-ray-grafted membranes. The results would be because local and high-density energy deposition due to the ion beam enabled us to control the membrane structure in a nanometer scale. We demonstrate our membranes are suitable for this application.

Journal Articles

Report of the 17th International Conference on Ion Sources (ICIS 2017)

Shinto, Katsuhiro

Kasokuki, 14(4), p.248 - 250, 2018/01

The 17th International Conference on Ion Sources (ICIS 2017) was held on 15th - 20th October 2017 at Geneva in Switzerland. This conference is held biennially. Most of scientists and engineers for ion sources in the world meet at the conference in order to share results of research and development.

Journal Articles

Effect due to RF discharge from a high intensity H$$^-$$ ion source upon the extracted beam

Shinto, Katsuhiro; Shibata, Takanori*; Wada, Motoi*

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.648 - 650, 2017/12

In J-PARC, peak H$$^-$$ current of several tens mA is extracted from an ion source driven by a solid-state rf amplifier with the frequency of 2 MHz for production of a cesiated hydrogen plasma. In case of the rf-driven ion source for producing the high-intensity H$$^-$$ current, the plasma density in the source chamber is so high that the ion sheath around the beam extraction area can follow the rf oscillation. The H$$^-$$ beam current fluctuation as large as approximately 1 mA was observed at the average beam current of 44 mA measured by a Faraday cup installed downstream of the ion source. The beam exhibited some fluctuation to the transverse motion as well. To further clarify this high frequency oscillation of the beam extraction sheath, we propose a measurement system using a time-resolved and highly sensitive emittance monitor in order to observe the real-time beam fluctuation in the phase space.

Journal Articles

Microfabrication of fluoropolymers using ion beam irradiation

Kitamura, Akane; Kobayashi, Tomohiro*

Hoshasen Kagaku (Internet), (104), p.29 - 34, 2017/10

no abstracts in English

Journal Articles

Formation of carbon alloys by low-energy ion doping and its application for adsorptive desulfurization

Shimoyama, Iwao

Hoshasen To Sangyo, (141), p.7 - 11, 2016/12

Desulfurization is an indispensable process on hydrogen formation from fossil fuel. Adsorptive desulfurization, alternative to conventional hydrogenation desulfurization, requires development of stable activated carbon adsorbents with high performance. I study dopant dependence on thiophene adsorption for carbon alloys prepared by heteroatom doping using low-energy ion beam. I doped nitrogen and phosphorus as dopants of group 15 elements in graphite surfaces, and clarified that phosphorus is superior in thiophene adsorption to nitrogen, and that the effect of phosphorus is higher with room temperature doping than with high temperature doping by about 10 times. X-ray absorption spectroscopy indicated that local structures around phosphorus sites were different between them. I attribute the high adsorption property to formation of curved phosphorus sites prepared by room temperature doping. Above results suggest that the property of carbon alloy can be controlled by low-energy ion beam.

Journal Articles

Present status of JAEA-Tokai tandem accelerator and booster

Matsuda, Makoto; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro

Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1413 - 1417, 2016/11

The tandem accelerator was operated over a total of 140 days and delivered 22 different ions to the experiments in the fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material. Maximum accelerating voltage is keeping up 18 MV and there was used for ten days on this voltage. However, electric discharge was occurred frequently in December and accelerating voltage fell to 12 MV. The damaged acceleration tubes were replaced with the spare tube at the regular maintenance period in March. The superconducting booster was not operated. This paper describes the operational status of the accelerators and the major technical developments.

JAEA Reports

Study on small-sized tailless beam formation using multipole magnetic field (Joint research)

Yokota, Wataru; Yuri, Yosuke; Watanabe, Shinichi*; Oshiro, Yukimitsu*; Kubono, Shigeru*

JAEA-Technology 2016-005, 21 Pages, 2016/03

JAEA-Technology-2016-005.pdf:2.24MB

The Center of Nuclear Science (CNS) of Tokyo University conducts the research on nuclear physics using CNS Radio-Isotope Beam Separator (CRIB) installed at the RIKEN AVF cyclotron. Takasaki Advanced Radiation Research Institute, JAEA has an AVF cyclotron of similar scale and is developing a technology to form a large-area uniform beam by an octupole magnetic field for the research on materials science. They carried out an R&D to increase the cyclotron beam intensity at a target under joint research. The nonlinear beam optics was designed to form a usual cyclotron beam having a large transverse tail into a small-sized tailless distribution so that the beam passes the gas target orifice (6 mm in diameter) of CRIB without a loss. As a result of particle tracking simulations based on the measured beam emittance, it has been found that an octupole magnetic field is effective in tail-folding and a 10-mm-diameter beam can be formed with two octupole magnets added in the present beam line. It has been also found that additional magnets need to be installed and the beam emittance should be reduced for the objective beam size of 6 mm. Moreover, the objective may be attained if the beam path length and configuration of the magnetic lens system are freely chosen.

Journal Articles

The Role of nitric oxide in radiation-induced bystander cell-killing effect

Yokota, Yuichiro; Funayama, Tomoo; Ikeda, Hiroko; Sakashita, Tetsuya; Suzuki, Michiyo; Kobayashi, Yasuhiko

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 67, 2016/02

The role of nitric oxide (NO) in bystander effect was investigated. Human fibroblasts were irradiated with $$gamma$$-rays (LET: 0.2 keV/$$mu$$m) or carbon-ion beam (108 keV/$$mu$$m), and then, co-cultured with the non-irradiated cells. After 24 h culture, the survival rates of non-irradiated cells and the concentrations of nitrate, an oxide of NO, in the medium were measured. The survival rates of non-irradiated cells decreased in dose-dependent and radiation quality-independent manners. Negative relationships between survival rates and nitrite concentrations existed, indicating the amounts of produced NO are an important determinant of bystander effects. Next, a reagent producing two molecules of NO in a half-life of 100 min was added in the culture medium. After incubation of 24 h the survival rates of treated cells did not decrease, suggesting NO produced intracellularly has an important role to lead the bystander effect but is not the signal molecule for intercellular communication.

Journal Articles

Screening of cesium-accumulating mutant of radioresistant bacterium ${it Deinococcus radiodurans}$ by ion beam breeding technology

Sato, Katsuya; Ueda, Ryoshiro*; Hase, Yoshihiro; Narumi, Issey*; Ono, Yutaka

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 100, 2016/02

Journal Articles

Quick measurement of continuous absorption spectrum in ion beam pulse radiolysis; Application of optical multi-channel detector into transient species observation

Iwamatsu, Kazuhiro*; Muroya, Yusa*; Yamashita, Shinichi*; Kimura, Atsushi; Taguchi, Mitsumasa; Katsumura, Yosuke*

Radiation Physics and Chemistry, 119, p.213 - 217, 2016/02

 Times Cited Count:1 Percentile:76.09(Chemistry, Physical)

A quick measurement system of a continuous absorption spectrum covering a wide range from 200 to 950 nm was constructed by employing an optical multi-channel detector. Ion beam pulse radiolysis with 12.5 MeV/u He, 18.3 MeV/u C and 17.5 MeV/u Ne ions were performed with the measurement system. Transient absorption spectrum of (SCN)$$_{2}$$$$^{-}$$ was clearly observed in KSCN aqueous solutions within a few minutes in spite of their very small absorbance, demonstrating high sensitivity of 0.001-0.003 in absorbance in the range from 260 to 660 nm as well as short measurement time of a few minutes. Two different absorption peaks attributed to Br$$_{2}$$$$^{-}$$ and Br$$_{3}$$$$^{-}$$ were observed simultaneously in NaBr aqueous solutions, showing powerfulness of the measurement system in overviewing chemical kinetics under ion beam irradiation especially in not well investigated chemical systems.

Journal Articles

Development of the negative ion beams relevant to ITER and JT-60SA at Japan Atomic Energy Agency

Hanada, Masaya; Kojima, Atsushi; Tobari, Hiroyuki; Nishikiori, Ryo; Hiratsuka, Junichi; Kashiwagi, Mieko; Umeda, Naotaka; Yoshida, Masafumi; Ichikawa, Masahiro; Watanabe, Kazuhiro; et al.

Review of Scientific Instruments, 87(2), p.02B322_1 - 02B322_4, 2016/02

 Times Cited Count:5 Percentile:43.38(Instruments & Instrumentation)

In International Thermo-nuclear Experimental Reactor (ITER) and JT-60 Super Advanced (JT-60 SA), the D$$^{-}$$ ion beams of 1 MeV, 40 A and 0.5 MeV, 22 A are required to produce 3600 s and 100 s for the neutral beam injection, respectively. In order to realize such as powerful D$$^{-}$$ ion beams for long duration time, Japan Atomic Energy Agency (JAEA) has energetically developed cesium (Cs)-seeded negative ion sources (CsNIS) and electro-static multi-aperture and multi-stage accelerators (MAMuG accelerator) which are chosen as the reference design of ITER and JT-60 SA. In the development of the CsNIS, a 100s production of the H$$^{-}$$ ion beam has been demonstrated with a beam current of 15 A by modifying the JT-60 negative ion source. At the higher current, the long pulse production of the negative ions has been tried by the mitigation of the arcing in the plasma inside the ion source. As for the long pulse acceleration of the negative ions in the MAMuG accelerator, the beam steering angle has been controlled to reduce the power loading of the acceleration grids A pulse duration time has been significantly extended from 0.4 s to 60 s at reasonable beam power for ITER requirement. The achieved pulse duration time is limited by the capacity of the power supplies in the test stand. In the range of $$<$$ 60 s, there are no degradations of beam optics and voltage holding capability in the accelerator. It leads to the further extension of the pulse duration time at higher power density. This paper reports the latest results of development on the negative ion source and accelerator at JAEA.

Journal Articles

Induced mutagenesis and breeding of plants

Ono, Yutaka; Yokota, Wataru

Kasokuki, 12(4), p.189 - 192, 2016/01

Journal Articles

Fabrication of Pt nanoparticle incorporated polymer nanowires by high energy ion and electron beam irradiation

Tsukuda, Satoshi*; Takahashi, Ryota*; Seki, Shuhei*; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito; Tanaka, Shunichiro*

Radiation Physics and Chemistry, 118, p.16 - 20, 2016/01

 Percentile:100(Chemistry, Physical)

Polyvinylpyrrolidone (PVP)-Pt nanoparticles (NPs) hybrid nanowires were fabricated by high energy ion beam irradiation to PVP thin films including H$$_{2}$$PtCl$$_{6}$$. Single ion hitting caused crosslinking reactions of PVP and reduction of Pt ions within local cylindrical area along an ion trajectory (ion track); therefore, the PVP nanowires including Pt NPs were formed and isolated on Si substrate after wet-development procedure. The number of Pt NPs was easily controlled by the mixed ratio of PVP and H$$_{2}$$PtCl$$_{6}$$. However, increasing the amount of H$$_{2}$$PtCl$$_{6}$$ led to decreasing the radial size and separation of the hybrid nanowires during the wet-development. Additional electron beam irradiation after ion beam improved separation of the nanowires and controlled radial sizes due to an increase in the density of crosslinking points inner the nanowires.

Journal Articles

Utilization of radiation facilities in Takasaki Advanced Radiation Research Institute under the MEXT grants

Hirota, Koichi

Hoshasen To Sangyo, (139), p.33 - 36, 2015/12

The article describes utilization programs for irradiation facilities for ion beam, $$gamma$$-ray and electron beam in Takasaki Advanced Radiation Research Institute under the MEXT (Ministry of Education, Sports, Culture, Science and Technology) grants. The feature of the facilities and technical support of assistants in the fields of creation of genetic resources, analytical technology, and material development under the grants are introduced. The article also includes recent research activities of development of new flowers, visualization of Li in lithium-ion battery, and development of distortion resistance of fluoro-rubber etc.

Journal Articles

Growth of single-phase nanostructured Er$$_2$$O$$_3$$ thin films on Si (100) by ion beam sputter deposition

Mao, W.*; Fujita, Masaya*; Chikada, Takumi*; Yamaguchi, Kenji; Suzuki, Akihiro*; Terai, Takayuki*; Matsuzaki, Hiroyuki*

Surface & Coatings Technology, 283, p.241 - 246, 2015/12

 Times Cited Count:1 Percentile:91.38(Materials Science, Coatings & Films)

Single-phase nanocrystalline thin films of Er$$_2$$O$$_3$$ (440) has been first prepared using Si (100) substrates by ion beam sputter deposition at 973 K at a pressure of $$<$$ 10$$^{-5}$$ Pa and $${it in}$$-$${it situ}$$ annealing at 1023 K at a pressure of $$approx$$ 10$$^{-7}$$ Pa. Er silicides formed during the deposition are eliminated via the annealing, which results in the single phase and the smooth surface of the Er$$_2$$O$$_3$$ thin films. The epitaxial relationship between Si (100) and Er$$_2$$O$$_3$$ (110) is clarified by X-ray diffraction and reflection high energy electron diffraction.

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