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Journal Articles

Development of radiation-resistant optical fiber for application to observation and laser spectroscopy under high radiation dose

Ito, Chikara; Naito, Hiroyuki; Nishimura, Akihiko; Oba, Hironori; Wakaida, Ikuo; Sugiyama, Akira; Chiyatani, Keiji

Journal of Nuclear Science and Technology, 51(7-8), p.944 - 950, 2014/07

 Times Cited Count:12 Percentile:75.09(Nuclear Science & Technology)

In the Fukushima Daiichi Nuclear Power Station, it is necessary to survey the locations and conditions of fuel debris inside reactor pressure vessels or primary containment vessels under water and radiation environment in preparation for removing fuel debris. An optical fiber is well known for features such as signal transmission, light weight, superior insulation performance, water resistance and electromagnetic noise resistance. These features allow the optical fiber to simplify the instrumentation systems for in-vessel inspection, as long as provide that the optical fiber can be used under high radiation dose environment. The radiation resistance of an optical fiber was improved by increasing the amount of hydroxyl up to 1000 ppm in pure silica fiber. The improved optical fibers were irradiated with $$gamma$$-ray up to 1 $$times$$ 10$$^{6}$$ Gy using a $$^{60}$$Co source. They indicated a large peak around 600 nm and a peak tail from ultraviolet region, but no large absorption in infrared region except a hydroxyl absorption peak of 945 nm. We have confirmed that the optical fiber containing 1000 ppm hydroxyl has enough radiation resistance for radiation induced transmission losses and the infrared imaging is effective for observation under high radiation doses.

Journal Articles

Hexavalent chromium reduction by an actinobacterium ${it Flexivirga alba}$ ST13$$^{rm T}$$ in the family ${it Dermacoccaceae}$

Sugiyama, Tomoyasu*; Sugito, Hironori*; Mamiya, Ko*; Suzuki, Yoshinori*; Ando, Katsuhiko*; Onuki, Toshihiko

Journal of Bioscience and Bioengineering, 113(3), p.367 - 371, 2012/03

 Times Cited Count:24 Percentile:68.56(Biotechnology & Applied Microbiology)

An isolated strain ${it Flexivirga alba}$ ST13$$^{rm T}$$ was examined for the reducing activity of hexavalent chromium (Cr(VI)). XANES analysis of the precipitate shows the presence of Cr(OH)$$_{3}$$, indicating the bacterial reduction of Cr(VI) to trivalent chromium (Cr(III)). The bacterial Cr(VI) reduction was more efficient in minimal medium supplemented with molasses than with glucose. These results strongly suggest that the isolate ${it F.alba}$ ST13$$^{rm T}$$ is a novel actinobacterium with Cr(VI) reducing activity that is stimulated by molasses.

Journal Articles

Possible existence of magnetic polaron in nearly ferromagnetic semiconductor $$beta$$-US$$_2$$

Ikeda, Shugo*; Sakai, Hironori; Tateiwa, Naoyuki; Matsuda, Tatsuma; Aoki, Dai*; Homma, Yoshiya*; Yamamoto, Etsuji; Nakamura, Akio; Shiokawa, Yoshinobu*; Ota, Yuki*; et al.

Journal of the Physical Society of Japan, 78(11), p.114704_1 - 114704_10, 2009/11

 Times Cited Count:10 Percentile:56.76(Physics, Multidisciplinary)

Journal Articles

Generation of stable and low-divergence 10-MeV quasimonoenergetic electron bunch using argon gas jet

Mori, Michiaki; Kondo, Kiminori; Mizuta, Yoshio*; Kando, Masaki; Kotaki, Hideyuki; Nishiuchi, Mamiko; Kado, Masataka; Pirozhkov, A. S.; Ogura, Koichi; Sugiyama, Hironori*; et al.

Physical Review Special Topics; Accelerators and Beams, 12(8), p.082801_1 - 082801_5, 2009/08

 Times Cited Count:21 Percentile:77.68(Physics, Nuclear)

The pointing stability and divergence of a quasimonoenergetic electron bunch generated in a self-injected laser-plasma acceleration regime using 4 TW laser is studied. A pointing stability of 2.4 mrad root-mean-square (RMS) and a beam divergence of 10.6 mrad (RMS) were obtained using an argon gas-jet target for 50 sequential shots, while these values were degraded by a factor of three at the optimum condition using helium. The peak electron energies were 8.5$$pm$$0.7 MeV and 24.8$$pm$$3.6 MeV using argon and helium, respectively. The experimental results indicate that the different propagation condition could be generated with the different material, although it is performed with the same irradiation condition.

Journal Articles

Application of laser-accelerated protons to the demonstration of DNA double-strand breaks in human cancer cells

Yogo, Akifumi; Sato, Katsutoshi; Nishikino, Masaharu; Mori, Michiaki; Teshima, Teruki*; Numasaki, Hodaka*; Murakami, Masao*; Demizu, Yusuke*; Akagi, Takashi*; Nagayama, Shinichi*; et al.

Applied Physics Letters, 94(18), p.181502_1 - 181502_3, 2009/05

 Times Cited Count:95 Percentile:94.5(Physics, Applied)

Journal Articles

Focusing and spectral enhancement of a repetition-rated, laser-driven, divergent multi-MeV proton beam using permanent quadrupole magnets

Nishiuchi, Mamiko; Daito, Izuru; Ikegami, Masahiro; Daido, Hiroyuki; Mori, Michiaki; Orimo, Satoshi; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Pirozhkov, A. S.; et al.

Applied Physics Letters, 94(6), p.061107_1 - 061107_3, 2009/02

 Times Cited Count:54 Percentile:87.76(Physics, Applied)

A pair of conventional permanent magnet quadrupoles is used to focus a 2.4 MeV laser-driven proton beam at a 1 Hz repetition rate. The magnetic field strengths are 55 T/m and 60 T/m for the first and second quadrupoles respectively. The proton beam is focused to a spot size (full width at half maximum) of 2.7$$times$$8 mm$$^{2}$$ at a distance of 650 mm from the source. This result is in good agreement with a Monte Carlo particle trajectory simulation.

JAEA Reports

Horonobe Underground Research Laboratory project overview of the pilot borehole investigation of the ventilation shaft (PB-V01); Geological investigation

Funaki, Hironori; Tokiwa, Tetsuya; Ishii, Eiichi; Hatsuyama, Yoshihiro*; Matsuo, Shigeaki*; Tsuda, Kazuyasu*; Koizumi, Akira*; Ishikawa, Taiki*; Daijo, Yuichi*; Sugiyama, Kazutoshi*

JAEA-Data/Code 2008-013, 65 Pages, 2008/08

JAEA-Data-Code-2008-013.pdf:6.38MB

We conducted geological investigation of the pilot borehole of the ventilation shaft in Horonobe during October 2007 and March 2008. This report describes the field operations (core description, core photograph, and core sampling) and laboratory measurements (modal analysis and X-ray diffraction analysis), equipments as well as processing procedures, and shows the obtained results. The information obtained from this investigation will be reflected in spring water control plan on shaft excavation and additional plan of drainage treatment facilities.

Oral presentation

Metamagnetic transition of heavy fermion U$$_2$$Zn$$_{17}$$

Ikeda, Shugo; Haga, Yoshinori; Tateiwa, Naoyuki; Matsuda, Tatsuma; Sakai, Hironori; Dung, N. D.; Yamamoto, Etsuji; Nakamura, Akio; Yamada, Tsutomu*; Sugiyama, Kiyohiro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Pressure effect of the paramagnet $$beta$$-US$$_2$$

Ikeda, Shugo; Sakai, Hironori; Matsuda, Tatsuma; Tateiwa, Naoyuki; Aoki, Dai*; Homma, Yoshiya*; Yamamoto, Etsuji; Nakamura, Akio; Shiokawa, Yoshinobu*; Ota, Yuki*; et al.

no journal, , 

no abstracts in English

Oral presentation

Pointing stabilization of electron beam driven by 4TW laser

Mori, Michiaki; Mizuta, Yoshio*; Kondo, Kiminori; Nishiuchi, Mamiko; Kado, Masataka; Kando, Masaki; Pirozhkov, A. S.; Kotaki, Hideyuki; Ogura, Koichi; Sugiyama, Hironori*; et al.

no journal, , 

The collimatability of quasi-monoenergetic electron beam production in the self-injected laser-plasma acceleration regime is studied. The collimation of electron beam drived by terawatt femtosecond laser (4.1 TW, 40 fs) is measured at two species of gas material (Helium gasjet and Argon gasjet). We measured 3.2 mrad pointing stability and beam divergence of 11 mrad (r.m.s.) at Argon gasjet for 50 sequencial shots. At such condition, the peak electron energy is 9.1$$pm$$1.0 MeV with 80% reproducebility. For Helium, the pointing stability is three times larger than that of Argon. It is considered that the laser channel formation is important role for stable electron beam generation.

Oral presentation

Pointing stability of quasi-monoenergetic electron bunch accelerated by laser wakefield

Mori, Michiaki; Mizuta, Yoshio*; Kondo, Kiminori; Nishiuchi, Mamiko; Kado, Masataka; Kando, Masaki; Pirozhkov, A. S.; Kotaki, Hideyuki; Ogura, Koichi; Sugiyama, Hironori*; et al.

no journal, , 

The stability and collimatability of quasi-monoenergetic electron beam production in the self-injected laser-plasma acceleration regime are studied. The collimation of electron beam drived by terawatt femtosecond laser (4.5 TW, 40 fs) is measured at two species of gas material (Helium gasjet and Argon gasjet). We measured 3.2 mrad pointing stability and beam divergence of 11 mrad (r.m.s.) at Argon gasjet for 50 continuous shots. At such condition, the peak electron energy is 9.1$$pm$$1.6 MeV. For Helium, the pointing stability is three times larger than that of Argon. It is considered that the laser channel formation is important role for stable electron beam generation.

Oral presentation

Proton acceleration and laser-plasma interaction diagnostics with J-KAREN laser

Pirozhkov, A. S.; Mori, Michiaki; Yogo, Akifumi; Kiriyama, Hiromitsu; Ogura, Koichi; Sagisaka, Akito; Ma, J.*; Orimo, Satoshi; Nishiuchi, Mamiko; Sugiyama, Hironori*; et al.

no journal, , 

Oral presentation

Transportation of the laser-driven MeV proton beam for the application; Spatial focusing and spectral enhancement with PMQs

Nishiuchi, Mamiko; Daito, Izuru; Mori, Michiaki; Orimo, Satoshi; Ogura, Koichi; Sagisaka, Akito; Sakaki, Hironao; Hori, Toshihiko; Yogo, Akifumi; Pirozhkov, A. S.; et al.

no journal, , 

From our previous research, we have successfully produce MeV proton beam by 1Hz repetition rate stabely from the interaction between the femto-second TW laser with solid target. Produced proton beam exhibits lower emittance. The number of proton beam is 10$$^{13}$$. However, it shows large divergence angle of 10 degree. The energy spectrum exhibits 100% energy spread. These are problematic for some specific applications. In this study we transported the laser-driven proton beam with permanent quadrapole magnet for the future application. We successfully obtain focused proton beam as well as the monochromatic proton beam. Those spatial distribution at the focus point as well as the spectral information is well reproduced by the montecalro simulation.

Oral presentation

Production of radioisotope from lithium using laser induced proton beams

Ogura, Koichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Orimo, Satoshi; Sagisaka, Akito; Nishiuchi, Mamiko; Mori, Michiaki; Yogo, Akifumi; Pirozhkov, A. S.; Sugiyama, Hironori*; et al.

no journal, , 

Protons with energies up to 3 MeV have been generated by the irradiation of a 7.5 $$mu$$m thickness target by a 1 Hz table top laser with intensity of 700mJ. These protons were used to induce the nuclear reaction 7Li(p,n)7Be. Simultaneously, energy of proton was detected by a time of flight method.

Oral presentation

Energetic proton beam generation driven by J-KAREN laser

Mori, Michiaki; Ogura, Koichi; Yogo, Akifumi; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Pirozhkov, A. S.; Sagisaka, Akito; Orimo, Satoshi; Tampo, Motonobu; Daito, Izuru; et al.

no journal, , 

Experimental studies of laser-driven ion acceleration aimed at ion therapy for cancer treatment are being conducted at the PMRC of JAEA using the J-KAREN Ti:Sapphire laser system at JAEA's APRC. In recent experiments thin foil targets have been irradiated with focused 38 fs laser pulses at the 1.8J laser energy. The energy spectrum of the proton beam is observed to extend to a cut-off value in excess of 7-MeV. Our results expose the prospects and challenges associated with developing a laser-driven ion therapy facility.

Oral presentation

Laser driven ion acceleration by J-KAREN laser at JAEA

Nishiuchi, Mamiko; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; Orimo, Satoshi; Tampo, Motonobu; Daito, Izuru; et al.

no journal, , 

no abstracts in English

Oral presentation

Proton generation from a thin-foil target by using a high-intensity laser

Sagisaka, Akito; Mori, Michiaki; Pirozhkov, A. S.; Yogo, Akifumi; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Tampo, Motonobu; Sakaki, Hironao; Hori, Toshihiko; et al.

no journal, , 

no abstracts in English

Oral presentation

Towards the laser-driven proton accelerator for cancer therapy; Benchmark test of the PARMILA code at the transport and irradiation test beam line

Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Yogo, Akifumi; Pirozhkov, A. S.; Sagisaka, Akito; Orimo, Satoshi; Mori, Michiaki; et al.

no journal, , 

no abstracts in English

Oral presentation

7-MeV class proton beam generation driven by J-KAREN laser

Mori, Michiaki; Ogura, Koichi; Yogo, Akifumi; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Pirozhkov, A. S.; Sagisaka, Akito; Orimo, Satoshi; Tampo, Motonobu; Daito, Izuru; et al.

no journal, , 

no abstracts in English

Oral presentation

Activity produced by laser induced proton beams

Ogura, Koichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Orimo, Satoshi; Sagisaka, Akito; Nishiuchi, Mamiko; Mori, Michiaki; Yogo, Akifumi; Pirozhkov, A. S.; Sugiyama, Hironori*; et al.

no journal, , 

Ultrashort and high intensity laser can induce high energy protons. Proton beams have a wide range of applications such as in the production of radioisotopes and proton therapy. An energy of the proton beam has a wide distribution. The distribution of activity in depth is calculated while laser induced protons are injected into an iron plate.

29 (Records 1-20 displayed on this page)