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Journal Articles

Fluorine analysis of human enamel around fluoride-containing materials under different pH-cycling by $$mu$$-PIGE/PIXE system

Komatsu, Hisanori*; Yamamoto, Hiroko*; Matsuda, Yasuhiro*; Kijimura, Taiki*; Kinugawa, Michihiko*; Okuyama, Katsushi*; Nomachi, Masaharu*; Yasuda, Keisuke*; Sato, Takahiro; Oikawa, Masakazu*

Nuclear Instruments and Methods in Physics Research B, 269(20), p.2274 - 2277, 2011/10

 Times Cited Count:18 Percentile:78.97(Instruments & Instrumentation)

Journal Articles

Quantitative analysis of cisplatin sensitivity of human esophageal squamous cancer cell lines using in-air micro-PIXE

Tanaka, Naritake*; Kimura, Hitoshi*; Faried, A.*; Sakai, Makoto*; Sano, Takaaki*; Inose, Takanori*; Soda, Makoto*; Okada, Koji*; Nakajima, Masanobu*; Miyazaki, Tatsuya*; et al.

Cancer Science, 101(6), p.1487 - 1492, 2010/06

 Times Cited Count:12 Percentile:31.84(Oncology)

We examined the intracellular localization of cisplatin, a key chemotherapeutic agent, in esophageal cancer cell lines and determined their sensitivity to cisplatin using in-air micro-PIXE. Two human esophageal squamous cell carcinoma (ESCC) cell lines, TE-2 and TE-13, were examined for their response to cisplatin using MTT assay, flow cytometry and DNA fragmentation assays. Real-time reverse transcription-polymerase chain reaction was also used to evaluate the mRNA expression of multidrug resistance protein 2 (MRP2) in both cell lines. Platinum localizations of intracellular and intranuclear were measured using in-air micro-PIXE. TE-2 cells were more sensitive to cisplatin than TE-13 cells. The results of this study suggest that in-air micro-PIXE could be a useful quantitative method for evaluating the cisplatin sensitivity of individual cells. Finally, we speculate that MRP2 in the cell membrane may play an important role in regulating cisplatin sensitivity of ESCC cells.

Journal Articles

Fabrication of nanowires by varying energy microbeam lithography using heavy ions at the TIARA

Kamiya, Tomihiro; Takano, Katsuyoshi; Ishii, Yasuyuki; Sato, Takahiro; Oikawa, Masakazu*; Okubo, Takeru; Haga, Junji*; Nishikawa, Hiroyuki*; Furuta, Yusuke*; Uchiya, Naoyuki*; et al.

Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2317 - 2320, 2009/06

 Times Cited Count:7 Percentile:47.19(Instruments & Instrumentation)

Journal Articles

Transient current mapping obtained from silicon photodiodes using focused ion microbeams with several hundreds of MeV

Hirao, Toshio; Onoda, Shinobu; Oikawa, Masakazu*; Sato, Takahiro; Kamiya, Tomihiro; Oshima, Takeshi

Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2216 - 2218, 2009/06

 Times Cited Count:11 Percentile:59.93(Instruments & Instrumentation)

Single-Event Effects (SEEs) are triggered when an energetic heavy ion traverses a sensitive area in electric devices. Since the SEEs occur due to dense charge which is created along to ion track within the order of picoseconds, the measurement of such a high speed current signals is very important. Furthermore, the size of dense charge and their concentration depend on LET as well as energy of incident ions. This means that the transient currents induced in electronic devices by incidence of ions with various energies and LETs should be investigated to clarify the mechanism of SEEs for electronic devices. Especially, the evaluations using heavy ions with high energies more than a several hundred MeVs are very important to understand the mechanism of SEEs observed in space. For this aim, we have developed an irradiation system of focused heavy ion microbeams at a several hundreds of MeVs at JAEA. In this paper, we study transient currents induced in Si photodiodes using the focused heavy ion microbeam irradiation system. The mapping of charge collected from the photodiodes irradiated with 260 MeV $$^{20}$$Ne$$^{7+}$$ ion microbeams, which is firstly observed in the world, will be presented. In addition, the difference in transient currents induced by ions at several hundred MeVs from ions at tens MeVs is discussed using TCAD (Technology Computer Aided Design) and GUN theorem.

Journal Articles

Quick change of ion species of heavy-ion microbeam by cocktail beam acceleration technique with the JAEA AVF cyclotron

Kurashima, Satoshi; Yoshida, Kenichi; Oikawa, Masakazu*; Sato, Takahiro; Miyawaki, Nobumasa; Yuyama, Takahiro; Okumura, Susumu; Kashiwagi, Hirotsugu; Ishibori, Ikuo; Nara, Takayuki; et al.

Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2024 - 2027, 2009/06

 Times Cited Count:10 Percentile:56.83(Instruments & Instrumentation)

A heavy-ion microbeam with energy of hundreds of MeV is utilized for research in biotechnology and materials science at the JAEA AVF cyclotron facility. Beam users need microbeams providing a wide range of linear energy transfer (LET). In order to vary LET widely, we have to change the ion species and/or energy. A cocktail beam acceleration technique is frequently used to change the ion species quickly. Ion species and energy can be changed by slightly shifting the acceleration frequency. The cocktail acceleration technique has been applied to microbeam production for quick change of ion species of a microbeam. As a result, we have succeeded to reduce considerably microbeam changing time to within 30 minutes between a 260 MeV Ne and a 520 MeV Ar. No deterioration of a microbeam spot size has been confirmed using a secondary electron microscope image of a copper mesh.

Journal Articles

Characteristics of focusing high-energy heavy ion microbeam system at the JAEA AVF cyclotron

Oikawa, Masakazu*; Sato, Takahiro; Kamiya, Tomihiro; Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro*; Sakai, Takuro; Yokota, Wataru

Applied Radiation and Isotopes, 67(3), p.484 - 487, 2009/03

 Times Cited Count:5 Percentile:41.12(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Development of micromachining technology in ion microbeam system at TIARA, JAEA

Kamiya, Tomihiro; Nishikawa, Hiroyuki*; Sato, Takahiro; Haga, Junji; Oikawa, Masakazu*; Ishii, Yasuyuki; Okubo, Takeru; Uchiya, Naoyuki; Furuta, Yusuke*

Applied Radiation and Isotopes, 67(3), p.488 - 491, 2009/03

 Times Cited Count:4 Percentile:30.6(Chemistry, Inorganic & Nuclear)

Development of a mask-less ion beam lithography technique for fabricating micro- or nano-meter sized structures has been started at the microbeam systems in the ion accelerator facility of JAEA Takasaki (TIARA) in collaboration with Shibaura Institute of Technology. In order to obtain a high precision measure for microbeam size estimation and lens system optimization, or for improvement of spatial resolution down to 100 nm level, we applied this lithography technique itself combined with the electroplating process to make a Ni relief pattern as an optimum resolution standard to be used in secondary electron imaging. In this work, using this standard, the smallest beam size could be obtained. This paper also discuses on the scattering of ions in the materials influenced to the resolution using a Monte Carlo simulation code.

Journal Articles

Developments for reduction of beam energy spread and formation of a few hundreds MeV class heavy-ion microbeam at a cyclotron

Kurashima, Satoshi; Miyawaki, Nobumasa; Oikawa, Masakazu*; Sato, Takahiro; Yoshida, Kenichi; Kashiwagi, Hirotsugu; Okumura, Susumu; Fukuda, Mitsuhiro*; Kamiya, Tomihiro; Yokota, Wataru

JAEA-Conf 2008-012, p.48 - 50, 2009/03

no abstracts in English

Journal Articles

Fast single-ion hit system for heavy-ion microbeam at TIARA cyclotron

Yokota, Wataru; Sato, Takahiro; Oikawa, Masakazu*; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Kamiya, Tomihiro

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 180, 2008/11

A fast single-ion hit system is being developed at the TIARA cyclotron using focused microbeam of several hundreds MeV with a spot of about 1 $$mu$$m in diameter. In order to achieve the goal hit rate of over 10/s, a magnetic scanner for the microbeam formation technique was replaced with a fast electrostatic scanner. The results of irradiation experiments show that the hit rate is higher than 10/s, the irradiation area is wider than 1000 $$mu$$m$$times$$1000 $$mu$$m and the targeting accuracy is independent of hit rate. In addition, a test operation of quick change of ion species of microbeam was carried out applying the cocktail beam acceleration technique. Ion species was successfully changed in 30 minutes while the microbeam formation takes about 8 hours including cyclotron tuning. The result strongly indicates that we will be able to provide a different microbeam for plural ion species in an irradiation experiment by turns.

Journal Articles

Ni electroplating on a resist micro-machined by proton beam writing

Uchiya, Naoyuki*; Furuta, Yusuke*; Nishikawa, Hiroyuki*; Watanabe, Toru*; Haga, Junji; Sato, Takahiro; Oikawa, Masakazu; Ishii, Yasuyuki; Kamiya, Tomihiro

Microsystem Technologies, 14(9-11), p.1537 - 1540, 2008/10

 Times Cited Count:17 Percentile:64.39(Engineering, Electrical & Electronic)

Journal Articles

Intracellular changes of metal elements by fucoidan extracted from brown seaweed; ${it Cladosiphon okamuranus}$

Nagamine, Takeaki*; Takada, Hisashi*; Kusakabe, Takahiko*; Nakazato, Kyomi*; Sakai, Takuro; Oikawa, Masakazu*; Kamiya, Tomihiro; Arakawa, Kazuo; Iha, Masahiko*

Biological Trace Element Research, 124(1), p.60 - 69, 2008/07

 Times Cited Count:2 Percentile:6.92(Biochemistry & Molecular Biology)

This study was undertaken to elucidate the intracellular changes of metal elements after the administration of fucoidan extracted from ${it Cladosiphon okamuranus}$. TRL1215 cells (normal rat liver cell line) were treated with 0, 0.1, or 1.0 mg/mL fucoidan. The cellular distribution of elements was analyzed using in-air micro-PIXE induced X-ray emission. In fucoidan-treated cells, the focal accumulation of Br (BrdU) was correlated spatially with phosphorous-rich region, suggesting that Br was localized within the nucleus. Al distribution provided a spatial association with Br map. These data suggest that fucoidan binding Al us postulated to be transferred into the nucleus.

Journal Articles

Subcellular changes of essential metal shown by in-air micro-PIXE in oral cadmium-exposed mice

Nakazato, Kyomi*; Nagamine, Takeaki*; Suzuki, Keiji*; Kusakabe, Takahiko*; Moon, H. D.*; Oikawa, Masakazu*; Sakai, Takuro; Arakawa, Kazuo

Biometals, 21(1), p.83 - 91, 2008/02

 Times Cited Count:15 Percentile:29.46(Biochemistry & Molecular Biology)

To clarify the relation of essential metals to cadmium (Cd) toxicity, we evaluated metallothionein expression and analyzed the subcellular distribution of essential metals using in-air micro-PIXE. Four mice were dosed orally with 100 mg/L of Cd in drinking water for 1.5 or 2 years. Compared to the control, the Cd-exposed mice markedly accumulated zinc in the liver and renal cortex. Elemental maps showed that a large amount of Cd was spatially combined with zinc in the 1.5y-Cd mouse. The data suggest that zinc may contribute to protect against oral-administrated Cd toxicity.

Journal Articles

Characterization of homoionic Fe$$^{2+}$$-type montmorillonite; Potential chemical species of iron contaminant

Kozai, Naofumi; Inada, Koichi*; Adachi, Yoshifusa*; Kawamura, Sachi*; Kashimoto, Yusuke*; Kozaki, Tamotsu*; Sato, Seichi*; Onuki, Toshihiko; Sakai, Takuro; Sato, Takahiro; et al.

Journal of Solid State Chemistry, 180(8), p.2279 - 2289, 2007/08

 Times Cited Count:14 Percentile:48.32(Chemistry, Inorganic & Nuclear)

Fe$$^{2+}$$-montmorillonite with Fe$$^{2+}$$ ions occupying cation exchange sites is an ideal transformation product in bentonite buffer material. We previously prepared a Fe$$^{2+}$$-montmorillonite sample using a FeCl$$_{2}$$ solution under an inert gas condition. This study attempted to determine the potential contaminant iron chemical species in the sample. It was found that a small amount of Cl$$^{-}$$ ions remained dispersed throughout the sample. The Cl$$^{-}$$ ion retention may be due to the adsorption of FeCl$$^{+}$$ in the initial FeCl$$_{2}$$ solution and the subsequent containment of the Cl$$^{-}$$ ions that are dissociated from the FeCl$$^{+}$$ during excess salt removal treatment. The latter may be explained by the slow release of the remaining Cl$$^{-}$$ ions from the collapsed interlayer of the montmorillonite or the transformation of a minor fraction of the remaining FeCl$$^{+}$$ to iron (III) hydroxide chloride complexes having low solubility.

Journal Articles

Improvement in beam quality of the JAEA AVF cyclotron for focusing heavy-ion beams with energies of hundreds of MeV

Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu; Oikawa, Masakazu*; Yoshida, Kenichi; Kamiya, Tomihiro; Fukuda, Mitsuhiro*; Sato, Takahiro; Nara, Takayuki; Agematsu, Takashi; et al.

Nuclear Instruments and Methods in Physics Research B, 260(1), p.65 - 70, 2007/07

 Times Cited Count:10 Percentile:59.19(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Focusing high-energy heavy ion microbeam system at the JAEA AVF cyclotron

Oikawa, Masakazu*; Sato, Takahiro; Sakai, Takuro; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Kurashima, Satoshi; Okumura, Susumu; Fukuda, Mitsuhiro*; Yokota, Wataru; Kamiya, Tomihiro

Nuclear Instruments and Methods in Physics Research B, 260(1), p.85 - 90, 2007/07

 Times Cited Count:40 Percentile:92.35(Instruments & Instrumentation)

A high-energy heavy ion microbeam system has been developed in an ion accelerator facility, TIARA of JAEA Takasaki. This was the first trial to focus heavy ion beams with an energy range of a few tens MeV/n from an AVF cyclotron accelerator in the world. The focusing system equipped with a quadruplet quadrupole magnet lens, multi beam collimators and beam scanners has been optimized following almost the same way as that of previously developed microbeam system in TIARA. However the ion beams from the cyclotron accelerator has a larger energy variation $$Delta$$E/E and also has a larger beam current instability $$Delta$$I/I than those of electro-static machine in general. We had to overcome these biggest problems in microbeam forming. This paper will outline the new focusing system we have developed in TIARA, and show the results of 1 $$mu$$m resolution by secondary electron mapping method and of single ion hit experiment for the track detectors and semiconductor test devices.

Journal Articles

Focused microbeam formation for heavy ion beam from AVF cyclotron, 2

Yokota, Wataru; Sato, Takahiro; Oikawa, Masakazu*; Sakai, Takuro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Kamiya, Tomihiro; Fukuda, Mitsuhiro*

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 185, 2007/02

The paper reports the progress in the development of the focusing microbeam formation technique in fiscal 2005, which is under way at the TIARA for application to research fields of biotechnology and semiconductor for space use. A 2-$$mu$$m-diameter microbeam was successfully attained using 260 MeV-$$^{20}$$Ne$$^{7+}$$ in fiscal 2004. The 1.7-$$mu$$m diameters on average were obtained at several experiments in the following fiscal year. This suggested that the microbeams might be usable for a several-hour experiment. The irradiation in the atmosphere was therefore tested for the first time. Furtheremore, a method to reduce an effect of vibration of apparatuses on the beam size was discussed, because 0.6-$$mu$$m amplitude in vibtation of the focusing lens was observed with a laser displacement sensor.

Journal Articles

1-D crosslinked polymer nanowires prepared by single particle nanofabrication techniques

Seki, Shuhei*; Tsukuda, Satoshi*; Tagawa, Seiichi*; Sugimoto, Masaki; Sato, Takahiro; Oikawa, Masakazu*; Sakai, Takuro

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 145, 2007/02

no abstracts in English

Journal Articles

Decrease in charge collection efficiency obtained for 6H-SiC n$$^{+}$$p diodes by Ni ion incidence

Oshima, Takeshi; Onoda, Shinobu; Oikawa, Masakazu*; Sato, Takahiro; Hirao, Toshio; Kamiya, Tomihiro; Ito, Hisayoshi

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 13, 2007/02

no abstracts in English

Journal Articles

Degradation of charge collection efficiency obtained for 6H-SiC n$$^{+}$$p diodes irradiated with gold ions

Oshima, Takeshi; Sato, Takahiro; Oikawa, Masakazu; Onoda, Shinobu; Hishiki, Shigeomi; Hirao, Toshio; Kamiya, Tomihiro; Yokoyama, Takuro*; Sakamoto, Airi*; Tanaka, Reisaburo*; et al.

Materials Science Forum, 556-557, p.913 - 916, 2007/00

 Times Cited Count:4 Percentile:76.87

no abstracts in English

Journal Articles

Developments at JAEA AVF cyclotron facility for heavy-ion microbeam

Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Ishibori, Ikuo; Yoshida, Kenichi; Sato, Takahiro; Kashiwagi, Hirotsugu; Yuri, Yosuke; Agematsu, Takashi; Nara, Takayuki; et al.

Proceedings of 18th International Conference on Cyclotrons and Their Applications (CYCLOTRONS 2007), p.131 - 133, 2007/00

We have been improving the beam quality of the JAEA (Japan Atomic Energy Agency) AVF cyclotron to form a several-hundred-MeV heavy-ion microbeam by a magnetic focusing lens. An energy spread ${it $Delta$E/E}$ of the order of 10$$^{-3}$$, obtained by ordinary acceleration using a fundamental dee voltage, makes it difficult to focus an ion beam to a spot size of 1 $$mu$$m in diameter with focusing lens because of the chromatic aberration. A flat-top acceleration system using the fifth-harmonic frequency of the acceleration frequency was installed in the cyclotron in order to reduce ${it $Delta$E/E}$ to the order of 10$$^{-4}$$. In addition, developments of a new center region, an energy spread measurement system using an analyzing magnet and a high performance beam buncher are in progress. The energy spread of the 260 MeV $$^{20}$$Ne$$^{7+}$$ beam has been reduced to 0.05% by the flat-top acceleration, and the microbeam with a spot size of approximately 1 $$mu$$m has been successfully formed.

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