Shimada, Koji; Sueoka, Shigeru
Fisshion, Torakku Nyusureta, (33), p.19 - 21, 2020/10
no abstracts in English
Yamamoto, Yuki*; Ishikawa, Norito; Hori, Fuminobu*; Iwase, Akihiro*
Quantum Beam Science (Internet), 4(3), p.26_1 - 26_13, 2020/09
The lattice constant and the magnetic state of CeO are modified by the irradiation with 200 MeV Xe ions. Under the assumption that these modifications are induced in the narrow one-dimensional region (the ion track) along the ion beam path, the dependence of the lattice constant and the saturation magnetization of CeO on the Xe ion fluence can be analyzed by using the Poisson distribution function. The analysis reveals that the lattice constant inside the ion track, which is larger than outside the ion track is not affected by the overlapping of the ion track. The present result implies that the Poisson distribution function is useful for describing the effect of ion track overlapping on the ion irradiation induced ferromagnetic state in CeO.
Kitamura, Akane; Ishikawa, Norito; Kondo, Keietsu; Yamamoto, Shunya*; Yamaki, Tetsuya*
Nuclear Instruments and Methods in Physics Research B, 460, p.175 - 179, 2019/12
Irradiation at grazing incidence formed chains of multiple hillocks on the surface of strontium titanate (SrTiO) and titanium oxide (TiO). They were observed with an atomic force microscope (AFM), however, the AFM measurement gives resolution errors in a nanometer order due to the curvature of the probe tip. To prevent these errors, a field emission scanning electron microscope (FE-SEM) would be a better option for observation. In this study, we performed SEM observations for the chains of the multiple hillocks. Single crystals of SrTiO and TiO were irradiated with 200 MeV Xe in the tandem accelerator at JAEA-Tokai. It was revealed that a lot of isolated hillocks were formed in a line on these surface. The diameter and the interval of those hillocks are discussed in comparison to AFM observation.
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). 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 using FE-SEM. Crystals of SrTiO(100) and 0.05 wt% Nb-doped SrTiO(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. On the SrTiO 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 surface.
Ishikawa, Norito; Taguchi, Tomitsugu*; Okubo, Nariaki
Nanotechnology, 28(44), p.445708_1 - 445708_11, 2017/11
TEM method is applied to YFeO (YIG) and three fluorides (CaF, SrF and BaF) for observing hillocks. For YIG which is one of the amorphizable materials, hillocks are found to have amorphous feature which is consistent with amorphous feature of ion-tracks. For the fluorides, it is found that the hillocks do not exhibit amorphous feature, and they are composed of nano-crystallites. It is found for the first time that for YIG the hillock diameter is comparable to the ion-track diameter, whereas for the fluorides it is always larger than the ion-track diameter. The results indicate that recrystallization after transient melting plays an important role for formation of hillocks and ion-tracks in fluorides.
Kitayama, Takumi*; Nakajima, Kaoru*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Matsuda, Makoto; Sataka, Masao*; Tsujimoto, Masahiko*; Isoda, Shoji*; Kimura, Kenji*
Nuclear Instruments and Methods in Physics Research B, 354, p.183 - 186, 2015/07
Esaka, Fumitaka; Suzuki, Daisuke; Magara, Masaaki
Analytical Chemistry, 87(5), p.3107 - 3113, 2015/03
The analysis of uranium particles in environmental samples taken from nuclear facilities is a useful tool to unveil undeclared nuclear activities related to the production of nuclear weapons. An efficient method to analyze isotope ratios of individual uranium particles is thermal ionization mass spectrometry (TIMS) combined with a fission track technique. A drawback in the fission track-TIMS technique is so-called particle-mixing. Here, some uranium particles are measured as a single particle and an averaged isotope ratio is obtained, which may lead to misunderstanding conclusions for source identification. In the present study, micro-sampling under a scanning electron microscope has been added to the procedure of the fission track-TIMS technique. The analysis of a mixed sample containing uranium particles in SRM 950a and CRM U100 materials indicated that the problem of particle mixing was almost avoidable with the proposed technique.
Kitabatake, Satomi*; Ushiroda, Tota*; Hirayama, Ryoichi*; Furusawa, Yoshiya*; Funayama, Tomoo; Yokota, Yuichiro; Okahata, Yoshio*; Ito, Atsushi*
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 86, 2015/03
Biological effects of high-LET radiation could be understood in terms of the ion track structure. Therefore the evaluation of the contribution of both core and penumbra regions to biological effects is an important issue for the study of high-LET effects. In the present study, we developed a protocol to make a uniform DNA sheet with insoluble nature in aqueous solution, and explored the applicability to the detection of 8-OHdG distributions after heavy-ion irradiation. Water-insoluble DNA sheet was irradiated with proton and neon ion beams at JAEA-Takasaki. After irradiation DNA samples were incubated with an 8-OHdG antibody followed by with a second antibody containing a fluorescence probe. The preliminary results indicated that upon ion irradiation randomly distributed dot-like fluorescence was observed, suggesting that these dots may be from incident ions.
Takaki, Seiya*; Yasuda, Kazuhiro*; Yamamoto, Tomokazu*; Matsumura, Sho*; Ishikawa, Norito
Nuclear Instruments and Methods in Physics Research B, 326, p.140 - 144, 2014/05
We have investigated atomic structure of ion tracks in CeO irradiated with 200 MeV Xe ions by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). TEM observations under inclined conditions showed continuous ion tracks with diffraction and structure factor contrast, and the decrease in the atomic density of the ion tracks was evaluated. High resolution STEM with high-angle annular dark-field (HAADF) technique showed that the crystal structure of the Ce cation column is retained at the core region of ion tracks, although the signal intensity of the Ce cation lattice is reduced over a region nm in size. Annular bright field (ABF) STEM observation has detected that the O anion column is preferentially distorted at the core region of ion tracks within a diameter of 4 nm.
Yamamoto, Tomokazu*; Shimada, Mikio*; Yasuda, Kazuhiro*; Matsumura, Sho*; Chimi, Yasuhiro; Ishikawa, Norito
Nuclear Instruments and Methods in Physics Research B, 245(1), p.235 - 238, 2006/04
We have investigated the microstructure change and atomic disordering process in magnesium aluminate spinel, MgO AlO with =1.1 and 2.4, irradiated with swift heavy ions of 200-MeV Xe and 350-MeV Au. Transmission electron microscopy techniques of bright-field (BF) and high-resolution (HR) imaging, as well as high angular resolution electron channeling X-ray spectroscopy (HARECXS) are employed in quantitative analysis of irradiation-induced structural change. Ion tracks show columnar dark contrast of 4-7 nm in diameter at the incident surface in BF images. Strong strain contrast often arises among plural ion tracks formed closely. Clear lattice fringes are observed in HR images even inside the ion tracks. It indicates that the spinel crystals are not amorphized but partially disordered along the ion tracks. Quantitative HARECXS analysis shows that cation disordering progresses with ion fluence. It is revealed that the disordered regions are extended over 122 nm in diameter along the ion tracks.
Kobayashi, Yasuhiko; Funayama, Tomoo; Wada, Seiichi; Sakashita, Tetsuya; Kakizaki, Takehiko; Hamada, Nobuyuki*; Yokota, Yuichiro; Furusawa, Yoshiya*
KEK Proceedings 2005-5, p.6 - 8, 2005/10
no abstracts in English
Nippon Shashin Gakkai-Shi, 68(1), p.56 - 59, 2005/02
In order to detect undeclared activities of nuclear facilities, Japan Atomic Energy Research Institute (JAERI) has developed analytical methods for safeguards environmental samples. As for particle analysis of safeguards environmental sample analysis which can determine isotope ratios of nuclear materials for individual particles, secondary ion mass spectrometry (SIMS) is known as a powerful method. However, it is difficult to analyze particles having diameter below 1 m due to its detection limit. To overcome the problem, JAERI is developing an analytical method using fission track (FT) technique. The outline of the method is described in this report.
Lee, C. G.; Iguchi, Kazunari; Inagawa, Jun; Suzuki, Daisuke; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Dai-26-Kai Kaku Busshitsu Kanri Gakkai (INMM) Nippon Shibu Nenji Taikai Rombunshu, p.171 - 178, 2005/00
Particle analysis by FT-TIMS method is effective for safeguards environmental samples because the isotope ratios of sub-micrometer particles can be determined. The FT-TIMS method developed by the authors, in which the particles are confined in the detector, has merits such as high detection efficiency and the possibility as a screening method for uranium particles according to their enrichment by controlling the etching time. However, it was found that a part of uranium particles contained in a detector may dissolve during the etching process of the detector. In order to overcome the problem, we are developing a novel sample preparing method in which the FT detector and the particle layer are separated. In the conventional FT sample of separated type, the detection process of particles of interest is time-consuming and complicated due to the discrepancy in position between tracks and particles. In contrast, the discrepancy was solved by fixing a part of a detector and a particle layer in our method, which improved the detection efficiency of particles containing fissile materials.
Magara, Masaaki; Usuda, Shigekazu; Sakurai, Satoshi; Watanabe, Kazuo; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Kono, Nobuaki; Inagawa, Jun; et al.
Proceedings of INMM 46th Annual Meeting (CD-ROM), 8 Pages, 2005/00
JAERI has been developing analytical techniques for ultra-trace amounts of nuclear materials in the environmental samples in order to contribute to the strengthened safeguards system. Development of essential techniques for bulk and particle analysis of the environmental swipe sample has been established as an ultra-trace analytical method of uranium and plutonium. In January 2003, JAERI was qualified as a member of the IAEA network analytical laboratories for environmental samples. Since then, JAERI has conducted the analysis of domestic and the IAEA samples. From Japanese fiscal year 2003, the second phase of the project was started for the development of advanced techniques, such as analyzing minor actinides and fission products as well as uranium and plutonium, particle analysis using fission-track technique, more efficient particle analysis using ICP-TOFMS and screening by X-ray fluorescent analysis. This paper deals with the progress in the development of the new techniques, applications and future perspective.
Hoshasen Kagaku, (77), p.2 - 7, 2004/05
no abstracts in English
Esaka, Fumitaka; Watanabe, Kazuo; Fukuyama, Hiroyasu; Onodera, Takashi; Esaka, Konomi; Inagawa, Jun; Iguchi, Kazunari; Suzuki, Daisuke; Lee, C. G.; Magara, Masaaki; et al.
Dai-25-Kai Kaku Busshitsu Kanri Gakkai Nippon Shibu Nenji Taikai Rombunshu, p.128 - 135, 2004/00
Japan Atomic Energy Research Institute (JAERI) was qualified as a member of the IAEA network analytical laboratories (NWALs) for particle and bulk analyses of safeguards environmental samples in January 2003. The particle analysis gives more detailed information on nuclear facility operation than the bulk analysis because the isotope ratios of nuclear materials in the samples collected inside nuclear facilities (swipe samples) can be determined for individual particles. We applied, as a method for uranium isotope ratio measurement, secondary ion mass spectrometry (SIMS) to particle analysis. Prior to the SIMS analysis, the particles in a swipe sample are recovered onto a carrier by impaction. The carriers with the recovered particles are then screened by total reflection X-ray fluorescence spectrometry. We integrated these techniques into a standard procedure, which is applied to domestic and IAEA swipe samples routinely.
Taguchi, Mitsumasa; Kojima, Takuji
JAERI-Review 2003-033, TIARA Annual Report 2002, p.141 - 142, 2003/11
no abstracts in English
Koizumi, Hitoshi*; Taguchi, Mitsumasa; Kojima, Takuji; Ichikawa, Tsuneki*
JAERI-Review 2003-033, TIARA Annual Report 2002, p.143 - 144, 2003/11
no abstracts in English
Kobayashi, Yasuhiko; Funayama, Tomoo; Wada, Seiichi; Taguchi, Mitsumasa; Watanabe, Hiroshi
Nuclear Instruments and Methods in Physics Research B, 210(1-4), p.308 - 311, 2003/09
A method for detecting the ion hit tracks on the mammalian cultured cells at the irradiation time was established. The cells were attached to the ion track detector CR-39 (100 m thick), then irradiated with 13.0 MeV/u 20Ne or 11.5 MeV/u 40Ar ion beams. Immediately after the irradiation, the cells were refilled with medium, then the CR-39 was etched from the opposite side of the cell with alkaline-ethanol solution at 37C. With the 15 min etching treatment, we obtained the accurate information about the spatial distribution of irradiated ions without significant effect on the cell growth. The continuous observation of the individual cell growth indicated that the growth of ion hit cell was reduced compared with that of non-irradiated one.
Yanase, Nobuyuki; Isobe, Hiroshi*; Sato, Tsutomu*; Sanada, Yukihisa*; Matsunaga, Takeshi; Amano, Hikaru
Journal of Radioanalytical and Nuclear Chemistry, 252(2), p.233 - 239, 2002/05
no abstracts in English